The 23rd International Conference on Few-Body Problems in Physics (FB23) will be held in Beijing, China on September 22-27, 2024, with Sept. 22 for registration.
This is the 23rd edition in the conference series which began in 1959 in London and was most recently held in Caen (2018) and Chicago (2015). The FB23 was originally scheduled in 2021 which was postphoned due to the pandemic.
Following the tradition the FB23 will cover a broad range of topics - in both theory and experiment - with the aim of bringing together diverse communities to generate and share brilliant ideas in few-body physics.
The subjects to be covered will include:
Ø Few-body aspects of atomic and molecular physics
Ø Hadrons and related high-energy physics
Ø Neutrinos and their interactions with matter
Ø Strange and exotic matter, including hypernuclear physics
Ø Few-nucleon systems, including QCD inspired approaches
Ø Few-body aspects of nuclear physics and nuclear astrophysics
Ø Interdisciplinary aspects of few-body physics and techniques
In addition to plenary and parallel sessions, a dedicated poster session will be organized. Keynote speakers will be encouraged to make their talks accessible to the entire community. All invited and contributed presentations, including posters, will be included in the conference proceedings.
As the conference is supported in part by the IUPAP, FB23 will be conducted in accordance with IUPAP principles. In particular, no bona fide scientists will be excluded from participation on the grounds of national origin, nationality, or political considerations unrelated to sciences.
FADDEEV MEDAL AWARD
FB23 will also be the venue for the presentation of the Faddeev Medal, which has recently been established jointly by the European (ERCFBP) and American (GFB) few-body communities. The 2024 edition of the award will include a formal announcement of the winner of the medal and a presentation by the winner at a dedicated session.
Following the tradition the FB23 will cover a broad range of topics - in both theory and experiment - with the aim of bringing together diverse communities to generate and share brilliant ideas in few-body physics.
PROCEEDINGS
Following the tradition of the FB conference series, the Proceedings will be published by journal. The relevant information on submission procedures will be published later on the Proceedings page of the website http://fb23.ihep.ac.cn .
I describe the new approach to derive consistently regularized nuclear forces and currents in chiral EFT using the symmetry-preserving gradient flow method.
The Thomas Jefferson National Accelerator Facility (also known as JLab) is a User Facility of the Office of Science of the U.S. Department of Energy, a premium nuclear physics facility at the forefront of exploring the nature of matter. JLab’s Energy Upgraded Continuous Electron Beam Accelerator Facility (CEBAF) can deliver electrons up to 11 GeV with high polarizations onto unpolarized and polarized targets in experimental Halls: A, B and C. In the newest experimental Hall D, electron beams up to 12 GeV impinged onto a diamond radiator are used to generate linearly polarized photon beams. The experimental programs at JLab are among the highest priorities in the 2023 Nuclear Science Advisory Committee (NSAC) Long Range Plan (LRP) for Nuclear Science. In this talk, I will present selected recent results from JLab and discuss some of the plans presented in the 2023 NSAC LRP. This work is supported in part by the U.S. Department of Energy under Contract No. DE-FG02-03ER4123.
The LHCb experiment is one of the four large experiments at the large hadron collider. It effectively covers the dominant kinematic region of b- and c-hadrons, and the detector is specifically designed to efficiently detect and identify the decay products of the heavy hadrons, making it an excellent laboratory for heavy hadron physics. LHCb keeps making significant contributions to hadron physics studies, marked by the discovery of 67 new hadrons so far, in particular the pentaquark states, the doubly charmed baryon and the fully charmed tetraquark state etc. In this talk, the recent progress on hadron physics from the LHCb experiment will be presented, including both hadron spectroscopy and hadron production results.
Quantum sensing technologies are opening new avenues to achieve unprecedented sensitivity and spatial resolution. Atomic Magnetometers are delivering important applications in biomedicine and fundamental physics. We propose a novel set-up consisting of multiple atomic magnetometers coupled together via a feedback magnetic field. We find the system exhibits rich nonlinear dynamics, including limit cycles, quasi-periodic orbits and chaos. We discuss the implications of these phenomena to quantum sensing.
This talk will present three recent studies conducted using data samples collected by the BESIII detector at center-of-mass energies ranging from 3.51 to 4.95 GeV. The investigations encompass hidden-charm, open-charm, and baryon final states. Specifically, the studies include the following: 1) Investigation of e+ e- -> K+ K- psi(2S), measuring the Born cross-sections and searching for new tetraquark candidates Z±cs in the decays Z±cs→K±ψ(2S); 2) Exploration of e+e−→D+sDs1(2536)− and e+e−→D+sD∗s2(2573)−, which reveals absolute branching fractions of Ds1(2536)−→D*0barK− and D∗s2(2573)−→D0barK− that challenge predictions based on the assumption of the Ds1(2536) and D∗s2(2573) being dominated by a bare csbar component, along with the discovery of intriguing resonant structures in the cross-section line shapes; 3) Examination of e+e- -> K Xi Lambda (Sigma), where the Born cross-sections are measured, and the first evidence of ψ(4160)→K−Ξ¯+Λ is observed.
Since 2003, many hadrons that do not fit into the conventional quark model of qqbar mesons and qqq baryons have been discovered experimentally. Because most (if not all) of these states are located to the thresholds of pair of conventional hadrons, they have been conjectured to be hadronic molecules. There have been extensive theoretical and experimental studies to verify or refute the molecular picture from different perspectives. In the past few years, we have proposed using femtoscopy to directly extract the underlying hadron-hadron interactions, which are key for forming hadronic molecules. In this talk, I will provide a pedagogic introduction to femtoscopy and its recent applications in understanding the nature of a few key candidates of hadronic molecules, such as Ds0*(2317), Pc(4457/4440), and Zc(3900)/Zcs(3985).
With the description that for a pure molecule state the effective range $r_0$ should satisfy the condition of $r_0 > 0$ and the fact that $r_0$ could be matched with the couplings related to momentum term in contact field theory, we can fit the low energy couplings up to NLO in the contact effective theory describing the 3 $P_c$ pentaquarks observed by LHCb in 2019 and finally get the effective range $r_0$. By comparing the sign of $r_0$, the spin of $P_c (4440)$ and $P_c (4457)$ could be distinguished, providing the conclusion that under the molecule picture, it's more natural to take $P_c(4440)$ as the $J^P=\frac{1}{2}^-$ $D^* \Sigma_c$ molecule and $P_c(4457)$ the $J^P=\frac{3}{2}^-$ one.
Whether the $N\bar{N}$ interaction could form a state or not is a long standing question, even before the observation of the $p\bar{p}$ threshold enhancement in 2003. The recent high statistic measurement in the $J/\psi \to \gamma 3(\pi^+\pi^-)$ channel would provide a good opportunity to probe the nature of the peak structures around the $p\bar{p}$ threshold in various processes. By constructing the $N\bar{N}$ interaction respecting chiral symmetry, we extract the pole positions by fitting the $p\bar{p}$ and $3(\pi^+\pi^-)$ invariant mass distributions of the $J/\psi \to \gamma p \bar p$ and $J/\psi \to \gamma 3(\pi^+\pi^-)$ processes. The threshold enhancement in the $p\bar{p}$ invariant mass distribution is from the pole on the third Riemann sheet, which more couples to the isospin triplet channel. The broader structure in the $3(\pi^+\pi^-)$ invariant mass comes from the pole on the physical Riemann sheet, which more couples to the isospin singlet channel. Furthermore, the large compositeness indicates that there should exit $p\bar{p}$ resonance based on the current experimental data. In addition, we also see a clear threshold enhancement in the $n\bar{n}$ channel, but not as significant as that in $p\bar{p}$ channel, which is useful and compared with further experimental measurement.
The strong attractive interaction of the ϕ meson and the proton is reported by ALICE collaboration recently. The corresponding scattering length is given as Re(f0)=0.85±0.34(stat)±0.14(syst)fm and Im(f0)=0.16±0.10(stat)±0.09(syst)fm. The fact that the real part is significant in contrast to the imaginary part indicates a dominate role of the elastic scattering, whereas the inelastic process is less important. In this work, such scattering processes are inspected based on a unitary coupled-channel approach inspired by Bethe-Salpeter equation. The ϕp scattering length is calculated based on this approach, and it is found that the experimental value of the ϕp scattering length can be obtained only if the attractive interaction of the ϕ meson and the proton is taken into account. A significant outcome of such attractive interaction is a two-pole structure in the ϕp scattering amplitude. One of the pole, locating at (1969−i283)~MeV might correspond to N(1895)1/2− or N(1875)3/2− listed in the review of the Particle Data Group(PDG). The other one, locating at 1949−i3~MeV should be a ϕN bound state, which has no counterpart in the PDG data.
Currently, the $DD^{\ast}$, $D\bar{K}$ and $D^{\ast}\bar{K}$ systems are studied from both theoretical and experimental sides. The three hadronic molecules $T_{cc}^+$, $D^\ast_{s0}(2317)$ and $D_{s1}(2460)$ are found in the above three two-body systems. We consider chiral effective field theory, get the interactions of $DD^{\ast}$, $D\bar{K}$, $D^{\ast}\bar{K}$ systems on lattice, find a model-independent three-body bound state in $DD^*\bar{K}$ system.
We study the baryon-baryon interactions with strangeness $S = -2$ and corresponding momentum correlation functions in leading order covariant chiral effective field theory. The relevant low energy constants are determined by fitting to the latest HAL QCD simulations, taking into account all the coupled channels. Extrapolating the so-obtained strong interactions to the physical point and considering both quantum statistical effects and the Coulomb interaction, we calculate the $\Lambda\Lambda$ and $\Xi^-p$ correlation functions with a spherical Gaussian source and compare them with the recent experimental data. We find remarkable agreement between our predictions and the experimental measurements by using the source radius determined in proton-proton correlations, which demonstrates the consistency between theory, experiment, and lattice QCD simulations. Moreover, we predict the $\Sigma^+\Sigma^+$, $\Sigma^+\Lambda$, and $\Sigma^+\Sigma^-$ interactions and corresponding momentum correlation functions. We further investigate the influence of the source shape and size of the hadron pair on the correlation functions studied and show that the current data are not very sensitive to the source shape. Future experimental measurement of the predicted momentum correlation functions will provide a non-trivial test of not only SU(3) flavor symmetry and its breaking but also the baryon-baryon interactions derived in covariant chiral effective field theory.
Highly excited Rydberg atoms exhibit strong and long-range interactions, opening new possibilities for scalable quantum information processing. Rydberg atom array is highly programmable and capable of achieving high-fidelity quantum operations, making it an excellent candidate for large-scale quantum computers. Moreover, the interactions between Rydberg atoms provide a new avenue for deterministic control of photonic quantum states. In principle, distributed quantum information processing can be achieved by combining these technologies in Rydberg atomic arrays and Rydberg quantum photonics. We plan to use Rydberg single-atom arrays to realize high-fidelity local quantum computing modules and connecting these modules through Rydberg quantum photonics techniques. In this talk, I will present our recent efforts along this direction. We have demonstrated defect-free, programmable two-dimensional arrays of hundreds of atoms, efficient manipulation of Rydberg states, single qubit gate fidelity of ~99.9%, and two-qubit gate fidelity of ~95%. Furthermore, we have achieved on-demand generation of near-optimal Rydberg single photons, with purity and indistinguishability both exceeding 99%, realizing quantum photonic logic gates with 99.8% fidelity. We also implemented Rydberg quantum entanglement filters, extracting high-fidelity quantum entanglement from input states with extremely low fidelity.
Non-Hermitian skin effect (NHSE) is a distinctive phenomenon in systems described by non-Hermitian Hamiltonians, where “bulk” eigenstates are spatially localized at the boundary of systems. In this talk, I will introduce a mechanism for particle separation based on their occupation conditions in the unit cells, which arises from the interplay between different skin accumulating channels and interactions between particles. Namely, at single-particle level, a directional reversal of NHSE can be induced by a destructive interference of non-reciprocity of different sublattices, which is eliminated for hardcore bosons (or fermions) that fully occupy a unit cell. In this way, “paired” and “unpaired” particles tend to accumulate toward opposite directions, which is demonstrated by both static eigensolutions and dynamical evolution.
Bound states in the continuum (BICs) are localized modes residing in the radiation continuum. They were first predicted for single-particle states, and became a general feature of many wave systems. In many-body quantum physics, it is still unclear what would be a close analog of BICs, and whether interparticle interaction may induce BICs. Here, we predict a novel type of multiparticle states in the interaction-modulated Bose-Hubbard model that can be associated with the BIC concept. Under periodic boundary condition, by constructing multiparticle Wannier states via projection position operator, a so-called quasi-BIC appears as a bound pair residing in a standing wave formed by the third particle. Under open boundary condition, such a hybrid state becomes an eigenstate of the system. We demonstrate that the Thouless pumping of the quasi-BICs can be realized by modulating the onsite interactions in space and time [1]. Surprisingly, while the center-of-mass of the quasi-BIC is shifted by a unit cell in one cycle, the bounded pair moves into bound pair moves in the opposite direction with the standing waves [2]. This is in stark contrast to Thouless pumping of bound states or topologically resonant pumping [3], where all particles move in the same direction. Our work not only paves an avenue to construct multiparticle BICs, but also may provide a new possibility to realize the Hilbert space fragmentation, many-body scars, and ergodicity breaking.
References
[1] Huang, B.; Ke, Y.; Liu, W.; and Lee, C.: “Topological pumping induced by spatiotemporal modulation of interaction” Phys. Scr. 99, 065997 (2024)
[2] Huang, B.; Ke, Y.; Zhong, H.; Kivshar, Y.; and Lee, C.: “Interaction-induced multiparticle bound states in the continuum” arXiv:2312.15664
[3] Ke, Y.; Qin, X.; Kivshar, Y.; and Lee, C.: “Multiparticle Wannier states and Thouless pumping of interacting bosons” Phys. Rev. A 95, 063630 (2017)
Quantum matter interacting with gauge fields, an outstanding paradigm in modern physics, underlies the description of various physical systems. Engineering artificial gauge fields in ultracold atoms offers a highly controllable access to the exotic many-body phenomena in these systems. Here we implement a triangular flux ladder in the momentum space of ultracold 133Cs atoms with tunable interactions. We reveal how the competition between interaction and flux in the frustrated triangular geometry gives rise to flux-dependent localization and biased chiral dynamics. For the latter in particular, the symmetry between the two legs is dynamically broken, which can be attributed to frustration. We then characterize typical dynamic patterns using complementary observables. Our work opens the avenue toward exploring correlated transport in frustrated geometries, where the interplay between interactions and gauge fields plays a key role.
In interacting many-body systems with chemical reactions, a key question is about how two-body decay depends on quantum correlations in interacting many-body systems. Here, we present a number of universal relations that directly connect two-body losses to other physical observables, including the momentum distribution and density correlation functions. These relations, which are valid for arbitrary microscopic parameters, such as the particle number, the temperature, and the interaction strength, unfold the critical role of contacts, a fundamental quantity of dilute quantum systems, in determining the reaction rate of quantum reactive particles in a many-body environment. Generalizations to reduced dimensions will also be discussed.
We present the determination of the charm quark mass, the masses and decay constants of charmed mesons using thirteen 2+1 flavor full-QCD gauge ensembles at five different lattice spacings $a\in[0.05,0.11]$ fm, 8 pion masses $m_{\pi}\in(130,360)$ MeV, and several values of the strange quark mass, which facilitate us to do the chiral and continuum extrapolation. These ensembles are generated through the stout smeared clover fermion action and Symanzik gauge actions with the tadpole improvement. Using QED-subtracted $D_s$ meson mass and non-perturbative renormalization, we predict the charm quark mass in the continuum with physical light and strange quark masses to be $m_c(m_c)=1.289(17)$ GeV in $\overline{\textrm{MS}}$ scheme, with the systematic uncertainties from lattice spacing determination, renormalization constant, and fit ansatz included. Predictions of the open and close charm mesons using this charm quark mass agree with the experimental value at 0.4\% level uncertainty. We obtained $D_{(s)}$ decay constants and also by far the most precise $D_{(s)}^*$ decay constants $f_{D^*}=0.2304(30)$ GeV and $f_{D^*_s}=0.2724(34)$ GeV, with the charm quark improved vector current normalization.
At BESIII, the R value is measured with the corresponding c.m. energy going from 2.2324 to 3.6710 GeV by measuring the inclusive hadronic cross section. An accuracy of better than 2.6% below 3.1 GeV and 3.0% above is achieved in the R values. Besides, the measurements of normalized differential cross sections of inclusive hadrons as a function of hadron momentum are performed at BESIII, for pi0, Ks, eta etc, which provide crucial information for the fragmentation Function (FF) describing the hadronization process.
We propose a novel method to probe light-quark dipole moments by examining the azimuthal asymmetries between a collinear pair of hadrons in semi-inclusive deep inelastic lepton scattering off an unpolarized proton target at the Electron-Ion Collider. These asymmetries provide a means to observe transversely polarized quarks, which arise exclusively from the interference between the dipole and the Standard Model interactions, thereby depending linearly on the dipole couplings. We demonstrate that this novel approach can enhance current constraints on light-quark dipole operators by an order of magnitude, free from contamination of other new physics effects. Furthermore, it allows for a simultaneous determination of both the real and imaginary parts of the dipole couplings, offering a new avenue for investigating potential $CP$-violating effects at high energies.
The BESIII experiment has collected 10 billion J/psi events, 2.6 billion psi(3686) events, and about 20 fb^-1 psi(3770) data. Various dark sectors produced in e+e- annihilation and hadron decay processes can be searched for at BESIII. In this talk, we report the search for invisible dark photon decay using initial state radiation, invisible muonic Z’ boson decay, sigma invisible decay, and search for axion-like particles with a light scalar or vector particle in the decay of J/psi.
The halo phenomenon is a hot topic in the nuclear structure study from both the theoretical and experimental points of view. Deep insights into the nucleon-nucleon interaction are needed to understand this phenomenon. Many neutron or proton-halo nuclei are observed in neutron or proton-rich nuclei by the experiments. With the strangeness quark included, the hyperon could influence the halo phenomenon, providing new insights into the baryon-baryon interaction. In this talk, we will investigate the hyperon halo orbits in light and heavy neutron-rich hypernucleus [1, 2]. We will also explore the possibility of a hyperon halo with a multi-hyperon hypernucleus. The lack of experiment data for the hyperon-hyperon interaction provides a chance to discuss the influence of the ambiguity of the hyperon-hyperon interaction on the multi-hyperon halo.
[1] Ying Zhang, Hiroyuki Sagawa, and Emiko Hiyama, Hyperon halo structure of C and B isotopes, Phys. Rev. C 103, 034321 (2021).
[2] Ying Zhang, Hiroyuki Sagawa, and Emiko Hiyama, Prediction of Exotic Hyperon Halos in Neutron-Rich Zr Hypernuclei, Prog. Theor. Exp. Phys. 2022, 023D01 (2022).
Moiré physics has flourished since the realization of twisted bilayer graphene at magic angles. Thanks to the high controllability and clean environment, ultracold atoms are ideal platforms for studying moiré physics. In this talk, I will present our recent progress in this direction. Using spin-dependent optical lattices for Rb87, Jing Zhang's group at Shanxi University first realized the moiré lattice in 2023. Our theoretical analysis contributed to explaining the new phases found in the experiment. Recently, we have further investigated the single-particle energy spectrum as a function of the twisting angle. We found beautiful fractal patterns and explained such behaviors by mapping the twisted bilayer optical lattice into an extended Hofstadter model. We have also extended the moiré physics to three dimensions. We emphasize a key distinction of three-dimensional moiré physics: in three dimensions, the twist operation generically does not commute with the rotational symmetry of the original lattice, unlike in two dimensions, where these two always commute. Therefore, the moiré crystal can possess a different crystal structure compared with the original lattice. We show that various crystal structures can be generated by twisting a simple cubic lattice. This capability of changing crystal structure by twist offers a broad range of tunability of band dispersion, including topological or flat bands, which can lead to richer few-body and many-body effects after adding interactions. I will also discuss possible scenarios in the two-body sector.
We theoretically investigate the heteronuclear Efimov universality in three-body systems, specifically 87Rb87Rb40K and 133Cs133Cs6Li, which exhibit repulsive intraspecies interactions. Our study focuses on the three-body recombination (TBR) rates with J=0 symmetry on the positive side of the interspecies scattering length. We utilize the R-matrix propagation method within a hyperspherical coordinate framework, employing the Lennard-Jones potential to model atomic interactions. Our findings reveal one Efimov recombination minimum for the RbRbK system and two for the CsCsLi system. These Efimov features, in conjunction with experimental observations, provide an opportunity to test the universality of Efimov states. Additionally, our study highlights the impact of finite-range effects and non-resonant intraspecies scattering lengths in heteronuclear mixtures, offering valuable insights into the universality of three-body parameters in systems with positive intraspecies scattering lengths.
Complex adaptive learning behavior is intelligent. It is adaptive, learns in feedback loops, and generates hidden patterns as many individuals, elements or particles interact in complex adaptive systems (CASs). CASs highlight adaptation in life and lifeless complex systems cutting across all traditional natural and social sciences disciplines. However, discovering a universal law in CASs and understanding the formation mechanism, such as quantum entanglement or complex quantum coherent adaptation, remains highly challenging. Quantifying the uncertainty of CASs by probability waves, the authors explore the inherent logical relationship between Schrödinger's wave equation in quantum mechanics and Shi’s trading volume-price probability wave equation in finance. The authors find a non-localized wave equation in quantum mechanics if cumulative observable in a time interval represents momentum or momentum force in Skinner-Shi (reinforcement-frequency-interaction) coordinates. It supports the assumption that a universal law or an invariance of interaction exists in quantum mechanics and finance. The authors conclude that quantum entanglement is a coherent interaction between opposite, adaptive, and complementary forces instead of a superposition of two coherent states that mainstream Copenhagen interprets. The interactively coherent forces generate particles with two opposite properties in a bipartite complex adaptive quantum system, suggesting the second revolution in quantum theory.
Keywords: complex adaptive systems, complex adaptive learning, universal law, non-localized wave equation, interactively coherent entanglement, interactively coherent adaptation
PACS: 89.75.-k (Complex Systems); 89.65.Gh (Economics, Econophysics, Financial Markets, Business and Management); 03.65.Ud (Entanglement and Quantum Nonlocality)
The Gailitis-Damburg oscillations are the near threshold singularities of cross-sections of reactive scattering predicted to exist in some atomic systems [1, 2, 3]. Namely, above the threshold of excited state of neutrally charged atom an infinite series of logarithmically spaced maxima and minima of cross-section can arise. Although this phenomenon was predicted in the early 1960s, there is no strong experimental confirmation and only a few recent computational studies devoted to improving the conditions of experiments with antimatter have observed the signs of it [4, 5, 6].
We present the results of our theoretical study of the behavior of cross sections of low-energy scattering in the systems e+pe- and e-pe-. Our computational experiment is based on solution of the Merkuriev-Faddeev equations in the total orbital momentum representation [7, 8] and the recently obtained original theoretical results on the wave function asymptote for the three-body Coulomb system in the presence of particle-atom dipole potential [9]. The latter is critically important for obtaining the reliable results at sufficiently small above threshold energies [10]. We have observed the existence of the Gailitis-Damburg oscillations in the partial cross sections [11]. Surprisingly, some of the obtained results contradict the theory of Gailitis and Damburg. We discuss it in our talk.
References
1. M. Gailitis and R. Damburg, Sov. Phys. JETP 17, 1107 (1963)
2. M. Gailitis and R. Damburg, Proc. Phys. Soc. 82, 192 (1963)
3. P. G. Burke, R-Matrix Theory of Atomic Collisions (Springer, Heidelberg, 2011).
4. C.-Y. Hu, D. Caballero, and Z. Papp, Phys. Rev. Lett. 88, 063401 (2002)
5. I. I. Fabrikant, A. W. Bray, A. S. Kadyrov, and I. Bray, Phys. Rev. A 94, 012701 (2016)
6. M. Valdes, M. Dufour, R. Lazauskas, and P.-A. Hervieux, Phys. Rev. A 97, 012709 (2018)
7. V. V. Kostrykin, A. A. Kvitsinsky, and S. P. Merkuriev, Few Body Syst. 6, 97 (1989)
8. V. A. Gradusov, V. A. Roudnev, E. A. Yarevsky, and S. L. Yakovlev, Commun. Comput. Phys. 30, 255 (2021)
9. V. A. Gradusov, S. L. Yakovlev, Theor. Math. Phys. to appear (2024)
10. V. A. Gradusov, S. L. Yakovlev, Theor. Math. Phys. 217(2), 1777 (2023)
11. V. A. Gradusov, S. L. Yakovlev, JETP Letters, 119(3), 151 (2024)
Financial support from Russian Science Foundation grant No. 23-22-00109 is acknowledged.
We present a theoretical study of resonance lifetimes in a two-component three-body system, specifically examining the decay of three-body resonances into a deep dimer and an unbound particle. Utilising the Gaussian expansion method together with the complex scaling method, we obtain the widths of these resonances from first principles. We focus on mass ratios in the typical range for mixtures of ultracold atoms and reveal an intriguing dependence of the resonance widths: as the mass ratio increases, the widths show oscillations on top of an overall decaying behavior. In particular, for some mass ratios the resonance width vanishes, meaning that the resonance becomes in fact stable. Notably, near the mass ratio for Caesium-Lithium mixtures, we obtain nearly vanishing widths of the resonances which validates to treat them in the bound state approximation. In addition, we perform our analysis on the resonance widths in both one and three dimensions and find a qualitatively similar dependence on the mass ratio.
In this talk, we will introduce a new color basis system and confinement mechanism for multi-quark systems within QCD’s string-like framework. This approach extends the color Hilbert space for $QQ\bar{Q}\bar{Q}$ states to include a "hidden color" state that mixes with two-meson states, leading to an attractive potential sufficient for bound state formation. Using a realistic Hamiltonian model, we calculate the mass spectrum of tetraquarks via the complex scaling method, incorporating full coupling to two-meson thresholds. The results will be compared with those from the traditional color-dependent linear confinement potential to explore the impact on tetraquark spectra.
In this talk, I will discuss recent progress towards achieving self-consistency in the light-front quark model. Typically, observables are computed using the good (or plus) current; however, computations using other currents, such as the transverse or minus current, often suffer from inconsistencies, resulting in different values. Self-consistency can be achieved in the standard light-front quark model by following the Bakamjian-Thomas construction. I will demonstrate this for observables such as decay constants. Additionally, I will review some progress in constructing a realistic light-front wave function, which is crucial for understanding the structure of mesons.
We propose a chiral quark model that incorporates vector mesons and apply it to the study of the hadron spectrum. We consider the contributions of vector mesons within the framework of hidden local symmetry. Our results demonstrate a significant improvement in the masses of ground state baryons, including the nucleon, $\Lambda_c$, and $\Lambda_b$. We successfully reproduce the masses of all 45 experimentally confirmed ground states of mesons and baryons. Furthermore, our predictions for 21 ground states align well with the results obtained from lattice QCD analyses. This work represents the first successful achievement of all 45+21 ground states of mesons and baryons using a single set of parameters.
The observation of the $T_{c\bar{s}}(2900)$ indicates the potential existence of strange double charm pentaquarks based on the heavy antidiquark symmetry. We systematically study the mass spectra of strange double charm pentaquarks with strangeness $S=-1$ in both molecular and compact structures for quantum numbers $J^{P}=1/2^{-}$, $3/2^{-}$, $5/2^{-}$. By constructing the interpolating currents, the mass spectra can be extracted from the two-point correlation functions in the framework of QCD sum rule method. In the molecular picture, we find that the $\Xi_c^{'+}D^{\ast +}$, $\Xi_{c}^{\ast +}D^{\ast +}$, $\Xi_{cc}^{\ast ++}\bar{K}^{\ast 0}$ and $\Omega_{cc}^{\ast +}\rho^{+}$ may form molecular strange double charm pentaquarks. In both pictures, the masses of the $J^P=1/2^-, 3/2^-$ pentaquarks locate within the $4.2-4.6~\mathrm{GeV}$ and $4.2-4.5~\mathrm{GeV}$ regions, respectively. As all of them are above the thresholds of their strong decay channels, they behave as a broad state, making them challenging to be detected in experiment. On the contrary, the strange double charm pentaquark with $J^P=5/2^-$ lies below its strong decay channel, which may be a very narrow state and easy to be identified in experiment. The best observed channel is its semi-leptonic decay to double charm baryon. As the result, we strongly suggest experiments to search for $J^P=5/2^-$ strange double charm pentaquarks as a first try.
The effects of three-nucleon force (3NF) have been actively studied by using the nucleon-deuteron (Nd) scattering states. The differential cross sections of the elastic Nd scattering at the energy below 150 MeV can be well reproduced by the Faddeev calculation based on modern nucleon-nucleon (NN) interactions and 3NF. On the other hand, the data at 250 MeV was underestimated by the calculations with 3NF by 50%. And this large discrepancy between the data and the theory was also shown in the 2H(p, p)pn inclusive breakup reaction at forward angular region [1].
Now, we are working on the ONOKORO project, which aims to understand the formation of various clusters (d, t, 3He, alpha) within nuclei. In this project, a detailed understanding of knockout reactions is important, and the measurement of the pd breakup reaction as an elementary process plays an important part because deuteron cluster is rather fragile [2]. We had carried out new inclusive pd breakup reaction measurements at RCNP, Osaka university as part of this project.
We injected 230MeV proton beam onto the deuterated poly-ethylene (CD2) target which is used as a deuteron target, and detected scattered protons by using Grand-Raiden spectrometer (for theta_LAB = 27 – 61 degree) or LAS spectrometer (for theta_LAB = 27 – 98 degree). We got the numbers of yield of breakup reaction which is summed up to 10MeV excitation energy, and then deduced the angular distributions of the differential cross sections of inclusive breakup reactions. From the comparison, the theoretical calculation [2] was shown to reproduce experimental data well.
[1] S. Kuroita, et al., Few-Body Systems 50, 287 (2011).
[2] Y. Chazono, et al., PRC 106, 064613(2022).
An inner electron can generate a strong electromagnetic field at the nucleus, leading to the mixing of nuclear levels—a phenomenon known as nuclear hyperfine mixing (NHM). This effect can significantly alter nuclear properties, particularly the lifetimes of nuclear excited states. For instance, the lifetime of the $^{229}$Th isomer is reduced by five orders of magnitude, from $10^3$ seconds to $10^{-2}$ seconds, due to NHM [1]. Our recent findings reveal a novel NHM mechanism in the $^{205}$Pb isomer, where its lifetime is shortened by four orders of magnitude, from 15 minutes to 32 milliseconds [2].
The NHM effect greatly enhances the coupling between the nucleus and the electromagnetic field, resulting in the observed reductions in lifetime. This enhancement also extends to interactions with external laser fields. Under currently achievable intense laser fields, NHM can induce highly nonlinear responses in the $^{229}$Th nucleus, enabling very efficient nuclear isomeric excitation and nuclear high harmonic generation [3].
[1] V. M. Shabaev et al., Phys. Rev. Lett. 128, 043001 (2022).
[2] W. Wang and X. Wang, Phys. Rev. Lett. 133, 032501 (2024).
[3] H. Zhang, T. Li, and X. Wang, under review.
Multiphoton ionization of atoms and molecules, involving one or more intermediate states, has been extensively studied for several decades and remains a topic of significant interest. With advancements in attosecond laser techniques, intrinsic timing information in ionization processes has become accessible. In this work, we revisit the role of spin-orbit effects in resonance-enhanced multiphoton ionization (REMPI). Although it was proposed nearly 40 years ago that spin-orbit coupling could substantially alter the angular distribution of final photoelectrons, direct experimental evidence has been limited. Here, we present the first direct observation of the subtle but impactful role of spin-orbit interactions in the dynamics of REMPI. Additionally, we report femtosecond-scale dynamics of the spin-orbit effect and uncover an unusual time-dependence in the phase evolution of the photoelectron partial waves. Explaining these phenomena requires further theoretical advancements.
After obtaining eigenvalues and eigenfunctions of a particle in a a one dimensional box in the presence of Dunkl operator, we expand the calculations for a three-body systems and for two different Fermion case and Boson case we discuss some new transition that have not seen before.
An investigation considering the emergence of Rayleigh-Taylor (RT) and Kelvin-Helmholtz (KH) instabilities, which occur in initially immiscible configuration of homogeneous Bose-Einstein condensates confined in a two-dimensional circular box, will be reported. For the binary mixture, it has been considered the rubidium isotopes $^{85}$Rb and $^{87}$Rb. As verified, more sound wave generations are found to appear in the RT instability than in the KH instability. Further, it will be also reported instabilities that occur in the binary mixture when centrally and axially phase separated states are submitted to sudden transitions from immiscible to miscible regimes by reducing the inter-species interactions. In all the reported cases, it will be shown the associated kinetic energy spectra as functions of the wave number $k$, which roughly follow the $k^{-5/3}$ and $k^{-3}$ scaling behaviors at specific time intervals.
Since the discovery of the $\chi_{c1}(3872)$ (aka $X(3872)$) state, many states compatible with tetraquarks have been observed, and many theoretical models have been proposed to explain these observations. However, there is still no consensus on the nature of tetraquark states. Further experimental studies of tetraquark states will help to test the theoretical model.
The LHCb experiment, with its large heavy-flavour data samples and high-performance detector, offers unique opportunities to explore the nature of tetraquark states.
This presentation highlights recent progress in tetraquark research at LHCb.
Scattering amplitudes involving three-particle scattering processes are investigated within the isobar approximation which respects constraints from two- and three-body unitarity. The particular system considered is the $D^0D^{*+}-D^+D^{*0}$, where the $D^{*+}$~$(D^{*0})$ enters as a $p$-wave $D^+\pi^0$ or $D^0\pi^+$~($D^0\pi^0$ or $D^+\pi^-$) resonance. The interaction potentials in the coupled-channel $D^0D^{*+}-D^+D^{*0}$ system contain the $\sigma$, $\rho$, $\omega$ and $\pi$-exchange. The analytic continuation of the amplitudes across the three-body unitary cuts is investigated to search for poles on the unphysical Riemann sheets. Associated with an unstable particle $D^{*+}$~$(D^{*0})$ is a complex two-body unitarity cut, through which one can further analytically continue into another unphysical Riemann sheet. Dynamical singularities emerged from the $\pi$-exchange potential are stressed. The pole generated from the $D^0D^{*+}-D^+D^{*0}$ interaction and its line shape in $D^0D^0\pi^+$ break-up production are in agreement with double-charmed tetraquark $T_{cc}^+$ observed by the LHCb Collaboration.
The Schrodinger equation with a Yukawa type of potential is solved analytically. When different boundary conditions are taken into account, a series of solutions are indicated as Bessel function, the first kind of Hankel function and the second kind of Hankel function, respectively. Subsequently, the scattering processes of $K \bar{K}^*$ and $D \bar{D}^*$ are investigated. In the $K \bar{K}^*$ sector, the $f_1(1285)$ particle is treated as a $K \bar{K}^*$ bound state, therefore, the coupling constant in the $K \bar{K}^*$ Yukawa potential can be fixed according to the binding energy of the $f_1(1285)$ particle. Consequently, a $K \bar{K}^*$ resonance state is generated by solving the Schrodinger equation with the outgoing wave condition, which lie at $1417-i18$MeV on the complex energy plane. It is reasonable to assume that the $K \bar{K}^*$ resonance state at $1417-i18$MeV might correspond to the $f_1(1420)$ particle in the review of Particle Data Group(PDG). In the $D \bar{D}^*$ sector, since the $X(3872)$ particle is almost located at the $D \bar{D}^*$ threshold, the binding energy of it equals to zero approximately. Therefore, the coupling constant in the $D \bar{D}^*$ Yukawa potential is determined, which is related to the first zero point of the zero order Bessel function. Similarly to the $K \bar{K}^*$ case, four resonance states are produced as solutions of the Schrodinger equation with the outgoing wave condition. It is assumed that the resonance states at $3885-i1$MeV, $4328-i191$MeV and $4772-i267$MeV might be associated with the $Zc(3900)$, the $\chi_{c1}(4274)$ and $\chi_{c1}(4685)$ particles, respectively. As to the resonance state at $4029-i108$ MeV, no counterpart has been found in the PDG data. It is noted that all solutions are independent on the isospin.
This talk is based on [Eur.Phys.J.C 84 (2024) 8, 800]. A novel approach is proposed to probe the nature of the double charm tetraquark through the prompt production asymmetry between $T_{\bar{c}\bar{c}}^-$ and $T_{cc}^+$ in pp collisions. When comparing the compact tetraquark picture and hadronic molecular picture, we find that the former one exhibits a significantly larger production asymmetry, enabling the unambiguous determination of the tetraquark’s internal structure. Additionally, distinctive differences in the transverse momentum and rapidity distributions of $T_{\bar{c}\bar{c}}^-$ and $T_{cc}^+$ cross sections emerge, particularly at $p_T$ ≈ 2 GeV and y ≈ ±6 at a center-of-mass energy of 14 TeV. This work can be extended to the exploration of other double heavy tetraquark candidates, offering a versatile approach to advance our understanding of exotic hadrons.
The proton is the simplest element of matter and the deuteron is the simplest compound nucleus; however, the measurements of their charge radii present significant puzzles. These puzzles are still unresolved, as they originate from the fact that the radii measured with high precision in muonic spectroscopy differ from those measured in ordinal-atom spectroscopy and electron scattering.
To obtain the most reliable proton and deuteron charge radii for electron scattering, a new ultra-low energy electron scattering facility has been built at RARiS, Tohoku University. We have almost finished data taking for the proton and deuteron radius measurements, and analysis is ongoing. I will talk about the current status of our experiment.
Necessity of the three-nucleon forces (3NFs) have come to light in various nuclear phenomena, for example, binding energies of nuclei, and equation of state in nuclear matters. As numerically exact solutions of the Faddeev equations using 2N- and 3N-forces are now attainable for observables in nucleon-deuteron (Nd) scattering, intricate information of the 3NFs can be extracted by directly comparing high precision data obtained in Nd experiments and theoretical calculations. Various performances of deuteron-proton (d-p) elastic scattering experiments at 70-300 MeV/nucleon (MeV/N) have confirmed clear signatures of 3NF effects in results of the cross sections below 135 MeV/N, whereas data of spin observables and cross sections at 250 MeV/N or above have suggested deficiencies in the spin dependent parts and high momentum transfer regions of current 3NF models.
In view of determining the 3NFs, we now plan to measure the spin correlation coefficients for polarized deuteron-polarized proton scattering at 100 MeV/nucleon. This scattering experiment will be performed at RIKEN RIBF facility, using the polarized deuteron beam provided via the polarized ion source and the polarized proton target system based on triplet dynamic nuclear polarization method. Polarized cross sections of particles scattered in left, right, up, and down directions will be measured with a detector system (KuJyaku) incorporating multi-wired drift chambers and plastic scintillators. Data taken will be utilized to fix the low energy constants in chiral effective field theory.
The polarized proton target and the KuJyaku detector system, both of which have been newly developed for the polarized deuteron-polarized proton scattering experiment, underwent a beam test at RIKEN using unpolarized deuteron beam in January 2024.
In this conference, detailed explanations on the new d-p elastic scattering experiments and results on the experiment in January will be given.
The optical nonlinearities of most materials are exceedingly small, which often requires fairly intense light fields with many photons to observe notable nonlinear effects. On the other hand, the possibility to enhance optical nonlinearities to the level of individual photons holds a number of interesting prospects, scientifically as well as technologically. Here, two-dimensional, atomically thin systems of quantum emitters offer a promising approach to enter this regime of quantum nonlinear optics.
This talk will focus on two complementary platforms based on (i) ultracold atoms in optical lattices and (ii) excitons in Moiré superlattices of twisted bilayer quantum materials. In particular, I will outline different ideas of how the interaction between such spatially confined quantum emitters can be exploited to enhance nonlinearities and generate strong effective interactions between lattice-polaritons. Perspectives and implications for experiments and potential applications will also be discussed.
Ultracold atomic and molecular gases are important platforms for studying quantum effects. One advantage of ultracold atomic and molecular gases over other systems is that the interparticle interactions are tunable. This is due to the fact that scattering resonances can be induced between ultracold atoms or molecules using the external field. In the vicinity of resonance, interatomic interactions can be modulated from repulsion to attraction, and from strong interactions to no interactions. In this talk, we will introduce theoretical researches on the use of electric fields to induce resonant scattering in ultracold atomic and molecular gases.
Properties of near-threshold exotic hadrons in the spectrum of heavy quarks are sensitive to multi-body effects that are particularly relevant for states containing charmed quarks. I will discuss few-body effects in heavy flavour hadronic molecules at the example of the tetraquark Tcc+ state discovered recently by the LHCb collaboration and studied on the lattice.
We study the decays $\bar B^0 \to \bar K^0 \, X$, $B^- \to K^- \, X$, $\bar B^0_s \to \eta (\eta')\, X$, $\bar B^0 \to \bar K^{*0} \, X$, $B^- \to K^{*-} \, X$ , $\bar B_s^0 \to \phi \, X$, with $X \equiv X(3872)$, from the perspective of the $X(3872)$ being a molecular state made from the interaction of the $D^{*+} D^-, D^{*0} \bar D^0$ and $c.c.$ components. We consider both the external and internal emission decay mechanisms and find an explanation for the $\bar K^0 \, X$ and $K^- \, X$ production rates, based on the mass difference of the charged and neutral $D^* \bar D$ components. We also find that the internal and external emission mechanisms add constructively in the $\bar B^0 \to \bar K^0 \, X$, $B^- \to K^- \, X$ reactions, while they add destructively in the case of $\bar B^0 \to \bar K^{*0} \, X$, $B^- \to K^{*-} \, X$ reactions. This feature explains the decay widths of the present measurements and allows us to make predictions for the unmeasured modes of $\bar B^0_s \to \eta (\eta')\, X(3872)$ and $B^- \to K^{*-} \, X(3872)$. The future measurement of these decay modes will help us get a better perspective on the nature of the $X(3872)$ and the mechanisms present in production reactions of that state.
The work of Eur. Phys. J. C 83 (2023) 983 will be presented, in which we perform a fit to the LHCb data on the $T_{cc}(3875)$ state in order to determine its nature. We use a general framework that allows to have the $D^0 D^{*+}$, $D^+ D^{*0}$ components forming a molecular state, as well as a possible nonmolecular state or contributions from missing coupled channels.
This talk is based on [Phys.Rev.D 110 (2024) 1, 014001]. Recently entanglement suppression was proposed to be one possible origin of emergent symmetries. Here we test this conjecture in the context of heavy meson scatterings. The low-energy interactions of $D^{(*)}\bar D^{(*)}$ and $D^{(*)} D^{(*)}$ are closely related to the hadronic molecular candidates $X(3872)$ and $T_{cc}(3875)^+$, respectively, and can be described by a nonrelativistic effective Lagrangian manifesting heavy-quark spin symmetry, which includes only constant contact potentials at leading order. We explore entanglement suppression in a tensor-product framework to treat both the isospin and spin degrees of freedom. Using the $X(3872)$ and $T_{cc}(3875)^+$ as inputs, we find that entanglement suppression indeed leads to an emergent symmetry, namely, a light-quark spin symmetry, and as such the $D^{(*)}\bar D^{(*)}$ or $D^{(*)} D^{(*)}$ interaction strengths for a given total isospin do not depend on the total angular momentum of light (anti)quarks. The $X(3872)$ and $T_{cc}(3875)^+$ are predicted to have five and one isoscalar partner, respectively, while the corresponding partner numbers derived solely from heavy-quark spin symmetry are three and one, respectively. The predictions need to be confronted with experimental data and lattice quantum chromodynamics results to further test the entanglement suppression conjecture.
Nucleon-nucleon interaction, or nuclear force, is the crucial input for ab-initio calculation of modern nuclear physics. It plays a fundamental role in understanding all nuclear structure and reaction phenomena. Nuclear force is the residue of strong interaction among nucleons, including protons and neutrons, which are bound into a large variety of nucleus of diverse nature depending on the number of protons and neutrons, known as Chart of Nuclides. So far, three approaches are widely accepted when dealing with this issue: phenomenological nuclear force, chiral nuclear force and lattice quantum chromodynamics. In the present talk, we construct relativistic chiral nuclear force up to next-to-next-to leading order based on covariant chiral effective field theory, the results of which are in good agreement with experimental data.
To explore the properties of H-like dibaryon $\Lambda_c \Lambda_c(0^+)$, we proceed ab-initio calculation on lattice. Two Wilson-Clover ensembles are used with the same setup at $m_\pi \approx 303 \,$MeV and lattice spacing $a\approx0.07746\,$fm. We find the coupling between $\Lambda_c\Lambda_c$ and $\Xi_{cc}N$ or $\Sigma_c\Sigma_c$ couldn't convert the repulsion between two $\Lambda_c$s into attraction. Therefore single channel is considered. A discretized modification on L$\mathrm{\ddot{u}}$scher equation is firstly proposed in this work. Phase shift also shows the weak interaction and scattering length $a_0$ is $-1.43(49)\,$fm. Under this quark mass, we find no bound state relying on our calculation.
Halo nuclei are interesting nuclear systems at the edge of stability. In an EFT treatment (halo EFT) they can be described as a more tightly bound core plus the more loosely bound halo nucleons. The so-called two-neutron ($2n$) halo nuclei consisting of the core and two halo neutrons are a special class within the halo nuclei. Prominent examples are $^6$He and $^{11}$Li. In the EFT description they form an effective three-body system. Interesting observables related to these nuclei are inter alia neutron-neutron ($nn$) distributions measured following the knockout of the halo's core as well as the $E1$ strength distribution parameterizing the Coulomb dissociation cross section.
In the first part of the talk, I will focus on the $nn$ distributions following the knockout. They can be well described in the EFT. The basis is a three-body description of the ground state using the Faddeev equations. The knockout does not need to be treated explicitly, but the subsequent final-state interactions (FSIs) are taken into account by using Moller operators. I focus on kinematic conditions where all non-$nn$ FSIs are suppressed. The results are discussed in the context of studying the $nn$ interaction [Göbel et al., Phys. Rev. C 104 (2021)] as well as of investigating the universality of ($2n$) halo nuclei [Göbel et al., Phys. Rev. C 110 (2024)].
In the second part, I will talk about the $E1$ strength distribution of $^6$He. I will present a finite-range approach to the EFT as an alternative to the commonly used zero-range approach. This avoids the treatment of some peculiarities of zero-range EFTs related to energy-dependent potentials in the case of interactions parameterized by more than one effective-range expansion parameter. The zero-range and the finite-range results will be compared and some preliminary results for the NLO $E1$ distribution with FSIs will be shown.
Recent experimental measurements of the breakup of $^8{\rm B}$ proton-halo nucleus on a lead target at deep sub-barrier energies by Pakou et al.[1] and Yang et al.[2], have shown that the breakup channel is the main reaction channel at these energies. Further, these works indicated the effect of Coulomb polarization on the proton halo state, with the correlation information revealing that the prompt breakup dominating mechanism occurs predominantly on the outgoing trajectory. This was further investigated in [3], in which it was emphasized the role of the continuum states of
the projectile for the breakup to occur on the outgoing trajectory. By investigating the possible universality of such behavior for weakly-bound projectiles on heavy targets, we have followed a theoretical analysis, using continuum-continuum coupled channel calculations, considering the total fusion and breakup cross-sections in the interaction of the neutron-halo $^{11}$Be projectile on the same lead target $^{208}$Pb. In this case, with a confirmation of the same behavior, we further verified that such a feature emerges from the enhancement of the breakup cross-section, due to the continuum-continuum couplings coming exclusively from its Coulomb component. Therefore, by assuming that these couplings are delaying the breakup process (which is also in line with Refs.[4,5]), even without a full dynamical calculation, which could provide more support to our conclusion, we claim that such behavior should be associated with the projectile breaking up on the outgoing trajectory. In resume, we have shown in Ref.[6], which is being presented here, that the importance of the breakup channel over the total fusion channel, at energies below the Coulomb barrier, can also be extended to neutron-halo projectile on heavy targets. Based on the available investigations, one could anticipate this may be a universal feature in the breakup of weakly bound projectiles on heavy targets.
Corresponding author (Email): lauro.tomio@unesp.br
References:
[1] A. Pakou et al. Phys. Rev C 102, 031601 (2020).
[2] L. Yang et al. Nature Comm. 13, 7193 (2022).
[3] B. Mukeru, L.V. Ndala and M. L. Lekala, Pramana J. Phys. 95, 106 (2021).
[4] A. Dias-Torres and D. Quraishi, Phys. Rev. C 97, 024611 (2018).
[5] S. Kalkal et al., Phys. Rev. C 93, 044605 (2016).
[6] B. Mukeru, T. Sithole and L. Tomio, to appear in J. Phys. G (2024).
Neutron scattering off neutron halos can provide important information about the internal structure of nuclei close to the neutron drip line. In this work, we use halo effective field theory to study the $s$-wave scattering of a neutron and the spin-parity $J^P=\frac{1}{2}^+$ one-neutron halo nuclei $^{11}\rm Be$, $^{15}\rm C$, and $^{19}\rm C$ at leading order. In the $J=1$ channel, the only inputs to the Faddeev equations are their one-neutron separation energies. In the $J=0$ channel, the neutron-neutron scattering length and the two-neutron separation energies of $\rm ^{12}Be$, $\rm ^{16}C$ and $\rm ^{20}C$ enter as well. The numerical results show that the total $s$-wave cross sections in the $J=1$ channel at threshold are of the order of a few barns. In the $J=0$ channel, these cross sections are of the order of a few barns for $n$-$^{11}\rm Be$ and $n$-$^{19}\rm C$ scattering, and about 60 $\rm mb$ for the $n$-$^{15}\rm C$ scattering. The appearance of a pole in $p\cot\delta$ close to zero in all three cases indicates the existence of a virtual Efimov state close to threshold in each of the $^{12}\rm Be$, $^{16}\rm C$, and $^{20}\rm C$ systems. Observation of this pole would confirm the presence of Efimov physics in halo nuclei. The dependence of the results on the neutron-core scattering length is also studied.
The peculiar thermal relaxation property of neutron stars is characterized by significantly prolonged thermal relaxation time. By combining neutron star cooling simulations, we propose a simple analytical model to explain the peculiar thermal relaxation. We find that the introduction of neutron $^3P_2$ superfluidity and the dUrca process lead to these peculiar thermal relaxations. The former originates from the re-coupling of the neutron star's core and crust following the PBF process, while the latter results from the delayed thermal coupling between the neutron star's inner core and outer crust. The peculiar thermal relaxation properties of neutron stars can be used to constrain the internal physics of neutron stars, particularly the superfluid properties.
The proposed STCF is a symmetric electron-positron beam collider designed to provide e+e− interactions at a centerof-mass energy from 2.0 to 7.0 GeV. The peaking luminosity is expected to be 0.5×10^35 cm−2s−1. STCF is expected to deliver more than 1 ab−1 of integrated luminosity per year. The huge samples could be used to make precision measurements of the properties of XYZ particles; search for new sources of CP violation in the strange-hyperon and tau−lepton sectors; make precise independent mea-surements of the Cabibbo angle (theta)c) to test the unitarity of the CKM matrix; search for anomalous decays with sensitivities extending down to the level of SM-model expectations and so on. In this talk, the physics interests will be introduced as well as the the recent progress on the project R&D.
The study of light hadron decays has yielded significant insights into the fundamental properties of matter and the strong interactions between quarks. With the unprecedented statistics of 10 billion J/psi events collected with the BESIII detector, a wide range of processes involving light hadrons, including both light meson and hyperons, were explored for the new decay modes, new mechanisms and hyperon polarizations. In this talk, the recent significant progresses on the light hadron decays achieved at the BESIII experiment were highlighted.
Hadron spectroscopy studies can provide insights into the internal structure and dynamics of hadrons, thus improving our knowledge of the non-perturbative regime of QCD. The large b- and c-hadron yields at LHCb and the good performance of the LHCb detector make it an excellent laboratory for such studies, providing unique opportunities for both the precise measurement of properties of established hadrons and the search for new ones. This talk will present the recent experimental studies on conventional hadron spectroscopy at LHCb.
The LHCb experiment collected the world's largest sample of charmed hadrons in proton-proton collisions during LHC Run 1 and Run 2. With this data set, LHCb is offering an unprecedented opportunity to enhance our understanding of these particles through searching for new decay channels [1], measurement of b-baryon properties [2], measurement of the mass and production [3]. This presentation will discuss recent results based on beauty baryon decays at centre-of-mass energies of 7, 8 and 13TeV.
[1] R. Aaij et al. (LHCb Collaboration), J. High Energy Phys. 07 (2024) 140
[2] R. Aaij et al. (LHCb Collaboration), arXiv:2406.12111
[3] R. Aaij et al. (LHCb Collaboration), Eur. Phys. J. C 84, 237 (2024)
In the work of prediction [Phys. Rev. C60, 045203], it was found that the hidden color (CC) channel plays an important role in forming nonstrange d* bound state and which is consistent with the COSY experiment. In the above work, the proposed chiral quark model were utilized in dynamically solving the resonating group method (RGM) equations for scattering processes and bound states. In this talk, we make an extension and perform a systematical exploration on the possible and interesting dibaryon candidates with different strangeness, examining the effect from CC channel in forming each dibaryon candidate [Symmetry 15 (2023) 446].
Motivated by the recent progress in developing high-precision relativistic chiral nucleon-nucleon interactions, we study the antinucleon-nucleon interaction at the leading order in the covariant chiral effective field theory. The phase shifts and inelasticities with $J\leq 1$ are obtained and compared to their non-relativistic counterparts. For most partial waves, the descriptions of phase shifts and inelasticities in the leading-order covariant chiral effective field theory are comparable to those in the next-to-leading order non-relativistic chiral effective field theory, confirming the relatively faster convergence observed in the nucleon-nucleon sector. In addition, we search for bound states/resonances near the $\bar{N}N$ threshold and find several structures that can be associated with those states recently observed by the BESIII Collaboration.
In cluster models, the light nuclei are treated as few-body systems composed of alpha-clusters and valence nucleons, providing significant successful description for the states with well developed clustering structure. However, the shell-like states with melted alpha clusters is more general in low lying states, and the cluster breaking effect becomes significant above the 3N+N threshold. In this contribution, we discuss the formulation and dissolution of alpha-clusters in light nuclei, via extended cluster models with full consideration of cluster melting due to Pauli blocking in low-lying states and the breaking of alpha clusters in high-excited states. The wave functions for ground and excited states are effectively optimized via a newly proposed Control Neural Network method, and the spectra of light nuclei calculated fit well with experimental data. The melting and breaking mechanism of alpha-clusters are then manifested in various states by looking into the wave functions and observables of corresponding nuclei.
Experimental exploration of neutron dripline is very challenging, and neon is the heaviest nucleus measured neutron dripline experimentally. Prediction of dripline heavier nuclei than neon is currently depends on theoretical approaches. However, there exist strong model-dependence in the prediction of the dripline in theoretical approach. Nuclear Lattice Effective Field Theory is one of the ab initio approach to explore the quantum many-body systems. In this talk, I will give a talk about the nuclear properties of Oxygen isotopes near the neutron dripline using lattice Monte Carlo simulations.
Accessing continuum information in nuclear physics is challenging, especially in an ab initio setup. We present recent progress on this topic using finite-volume dependences. Finite-volume dependencies in nuclear physics are well-established analytical tools for numerical simulations. They reveal real-world properties from discrete energy levels in artificial finite boxes. In this talk, I briefly review Lüscher's original idea and then introduce recent developments for systems with long-range Coulomb forces and clusters. This progress allows the extraction of Asymptotic Normalization Constants in nuclear lattice simulations with minimum assumptions. We present two interesting applications to 20Ne and 16O ground-states.
Studies of pentaquark states can improve our understanding of the strong interaction at the low-energy region. In 2015, the first candidates for pentaquark states were observed at LHCb. Since then, significant experimental and theoretical efforts have focused on pentaquark research. However, the internal structure and dynamics of tetraquarks remain a topic of active debate, calling for more experimental input. The LHCb experiment, with its unique detector design and large dataset, is well-suited for pioneering pentaquark studies. In this talk, we present recent results on pentaquark states at LHCb.
In our work, we dynamically generate the bound states with the chiral unitary approach with the coupled channels, and evaluate the correlation functions for each channel. Then we address the inverse problem starting from these correlation functions to determine the scattering observables related to the system, including the existence of the bound state and its molecular nature. Assuming the correlation functions to correspond to real measurements, we make a fit to the data within a general framework to extract the information contained in these correlation functions. The bootstrap method is used to determine the uncertainties of the different observables, and we find that, assuming errors of the same order than in present measurements of correlation functions, one can determine the scattering length and effective range of all channels with a very good accuracy.
Femtoscopic correlations with the $π^0π^0$ pair are measured in photoprodution at $E_{\gamma}$=1.3−2.4 GeV to extract the space-time geometry of the pion emission region. The $π^0π^0$ photoprodution experiment was carried out at Spring-8 BL31LEP with a linearly polarized photon beam using a 4π electromagnetic calorimeter BGOegg. Enhancement due to quantum statistics arising from Bose-Einstein correlations at small relative momenta is observed. The Gaussian radius of the pion source is extracted at several photon beam energy bins. And the strength of the $π^0π^0$ correlations in the case where the $π^0N$ sequential decays are suppressed is greater than that in the case where the $π^0N$ sequential decays are note suppressed. Including strong final-state interaction (FSI) for $π^0π^0$ through resonances may provide more interesting information about possible existence of bound states and scattering parameters of the involved channels in the interactions.
We investigate the nucleon self energy through the sixth chiral order in the covariant SU(2) chiral perturbation theory (χPT) in the single baryon sector using the extended-mass-on-shell(EOMS) scheme. It is found that the EOMS scheme exhibits quite satisfactory convergence behavior through O(q^6) around physical point. We also predict the pion mass dependence of the nucleon mass to the accuracy of O(q^6), which is in satisfactory agreement with the recent lattice results over a wide range of pion mass.
Scattering reactions can be used to study the properties of hadron resonances. The traditional analysis method is to fit experimental data by adjusting the quantum number and parameters of the resonance. I would introduce a new method, which is the application of neural networks (NN), to study hadron resonances. The advantage of the NN method is that it can give quantitative probabilities in category classification of quantum numbers and potentially more stable in parameter determination. I would introduce the procedures of NN application and show its feasibility in the study of Sigma resonances through the K-p->piSigma reaction.
We will demonstrate the physical significance of the study of the semileptonic decay. The various theoretical tools such as the quark model will be explained.
We will dispay our prediction for several observables that can be tested in experiment.
Recently, the femtoscopic technique provided insights into the previously experimentally inaccessible strong interaction between hadron pairs, including strangeness or charm. The ALICE Collaboration has, for the first time, extended such measurements to three-hadron and hadron-nucleus systems. Such studies provide a pivotal input to a better understanding of exotic nuclei and three-body dynamics, including genuine three-body interactions. The latter, especially those containing hyperons, constitute an essential ingredient in the calculations of the equation of state of neutron stars.
The measurements of three-hadron correlation functions, including p-p-p and p-p-Λ triplets, will be presented in this talk. All results were obtained by analysing high-multiplicity pp collisions at sqrt(s) = 13 TeV measured by ALICE at the LHC. The three-body effects in these systems were modelled using pertinent calculations employing hyperspherical harmonics and state-of-the-art two-body interactions. Hadron-nucleus correlations, such as p-d systems, also provide access to the three-body dynamics. It was found that in small systems effective two-body calculations fail for the p-d system, which can be modelled satisfactorily only if theoretical calculations account for the underlying three-nucleon dynamics.
The nuclear reaction $^6$He+p was investigated at 8 MeV/u. $^6$He is a halo nucleus, and it has a three-body $\alpha$+n+n structure. It is the lightest halo nucleus and is bound by about 1 MeV against the $\alpha$+n+n breakup. Moreover, there is no core excitation in $^6$He and the interactions between the $^6$He constituents (i.e. the alpha particle and the neutrons) with the target (proton) are well known. The study of the elastic and neutrons transfer reactions for the $^6$He+p system could shed important properties on the transfer mechanisms and on the halo structure. The reaction was performed using a new developed exotic beam at CRIB (CNS, university of Tokyo). The $^7$Li(d,$^3$He)$^6$He reaction was used to produce the radioactive $^6$He beam: the $^7$Li primary particles were accelerated with the AVF cyclotron (RIKEN) at an energy of 8.3 MeV/u and the intensity and energy of the secondary $^6$He beam were 10$^5$ pps and 8 MeV/u respectively. The detection set-up for the charged particles was composed of 6 silicon telescopes at different angles and at a distance around 150 mm from the CH$_2$ target. We have measured simultaneously the $^6$He(p,p)$^6$He, $^6$He(p,t)$^4$He and $^6$He(p,d)$^5$He reactions in a wide angular range allowing a full description of the reaction processes. The breakup of the $^6$He was also observed. By investigating the 1n and 2n transfer reactions information on the halo structure could be inferred. The (p,t) and (p,d) reactions can be described in the DWBA formalism using $^6$He+p CDCC scattering wave-functions. Preliminary results will be presented.
The dynamics of the three-nucleon system can be extensively studied in the deuteron-proton (dp) breakup reaction. Experimental studies of the dp system allow for the observation of effects of various dynamical components, such as three-nucleon force (3NF) and Coulomb force. Measurements of cross sections as well as polarized observables (e.g. vector and tensor analyzing powers [1]) allow testing theoretical calculations based on various approaches [2 - 5] to model the interaction in three-nucleon systems. Additionally, studies of the $^1$H(d, pp)n reaction at low energy (e.g. 50 MeV/nucleon) are essential for testing predictions of Chiral Effective Field Theory (ChEFT) [6].
The presentation will focus on the effects of the 3NF and the Coulomb force in the differential cross section of the dp breakup reaction measured in the wide range of energies between 50 and 170 MeV/nucleon [8 - 11]. The data collected at 50 MeV/nucleon will be compared to predictions of ChEFT [7]. Furthermore, there will be information about the ongoing and planned projects conducted at the Cyclotron Center Bronowice, PAS, Kraków, Poland.
The validity range of the time-honored effective range expansion can be very limited due to the presence of a left-hand cut close to the two-particle threshold. Such a left-hand cut arises in the two-particle interaction involving a light particle exchange with a mass small or slightly heavier than the mass difference of the two particles, a scenario encountered in a wide range of systems. This can hinder a precise extraction of low-energy scattering observables and resonance poles. To address this issue, we propose a new parameterization for the low-energy scattering amplitude that accounts for the left-hand cut. The parameterization is like a Pad\'e approximation but with nonanalytic terms from the left-hand cut and can be regarded as an extension of the effective range expansion. It is ready to be applied to a broad class of scatterings and, in particular, should be invaluable in understanding various near-threshold hadron resonances. As byproducts, we also show that the parameterization can be used to extract the couplings of the exchanged particle to the scattering particles, and derive expressions for amplitude zeros caused by the interplay between the short- and long-range interactions.
Motivated by the recent BESIII report on $J/\psi\rightarrow\gamma K^S_0K^S_0\pi^0$ decay, we firstly perform a disperisve analysis to study the final-state-interactions (FSIs) in the three-body unitarity and try to gain some insights into the nature of long-standing puzzles of isos-scalar pseudo-scalar $\eta(1405/1475)$ which is related the radially excited states of $\eta-\eta'$ and pseudo-scalar glueballs. The two-body FSIs are established from the low-energy meson-meson scattering data within the Muskhelishvili-Omnes framework and then the generic three-body FSIs below 1.6GeV are learned by the Khrui-Trieman framework. The experimental data are described and the pole structure of $\eta(1405/1475)$ by analytical continuation will also be reported.
Charmed hadron decays offer an excellent environment for studying non-perturbative QCD. In addition, these decays involving scalar and vector mesons as final state particles play a crucial role in investigating the nature of scalar mesons, like a0 and f0, as well as examining the decay of vector mesons, like phi.
The BESIII experiment has collected 7.33 fb^-1 and 20 fb^-1 at 4.128-4.226 GeV and 3.773 GeV, respectively. In this talk, we will report our findings on the Lambda_c->Lambda a0(980) decay in Lambda_c->Lambda pi eta, as well as the measurements of the D(s)-> SP, SV, VP decays, in the amplitude analyses of D(s) three- and four-body decays. This includes the discovery of a new a0-like triplet and investigation of the W-annihilation-free decay D->K*eta. In addition, we will report our recent measurement of branching fraction of phi decays in charmed meson decays, revealing a result significant deviated from the PDG value. Furthermore, we will present our studies of D->S semi-leptonic decays, D(s)-> a0(980)/f0(980)/f0(500)/phi l nu, including the measurements of D->f0(980)/f0(500)/phi transition form factors.
The Similarity Renormalization Group (SRG) is a potent method explored for decoupling nuclear potentials, aimed at reducing computational demands in observable calculations. Its versatility and robustness in handling nuclear interactions offer a gateway to deeper insights into the renormalization process. These transformations, similar to the renormalization group, are typically unitary in nature, ensuring well-defined operations. Notably, they impose cutoffs on energy disparities instead of individual states, effectively removing off-diagonal matrix elements in the Hamiltonian matrix. As these cutoffs decrease, the Hamiltonian tends towards a band diagonal form.
One crucial advantage of SRG transformations is the decoupling of low-energy nuclear physics from high-energy one within the inter-nucleon interaction. This separation is pivotal for evaluating two-body observables and few-body binding energies and scattering observables like phase-shifts and scattering cross section. Simultaneously, SRG transformations induce many-body forces as it decouple the high-energy states in the Nuclear Hamiltonian. Despite its successful application in nuclear structural calculations, the SRG-transformed interaction has yet to be extensively utilized in addressing continuum problems in scattering reactions. My aim is to investigate whether employing the SRG method offers advantages in studying nuclear scattering reactions, probing its potential benefits in this domain and study the effects of these 3-body induced forces when taken into account.
Structure and correlations of nuclei at and beyond the neutron drip line have attracted lots of attention in the last decades. Strongly correlated neutrons may also form neutron clusters (e.g., 3n, 4n). Despite many experimental and theoretical efforts, the properties of these neutron clusters still remain elusive. To study the structure of the extremely neutron-rich nuclei and the correlations between the constituent neutrons, we are now developing a new neutron detector array, Advanced Multi-neutron Detection Array (AMDA), aiming for high-resolution and high-efficiency multi-neutron detection. A prototype array has been built, which is composed of four detector units each consisting of the BC408 plastic scintillator with a size of 2cm2cm100cm and SiPM. The time and position resolution, and the attenuation length have been determined from the cosmic ray test.
The structure of neutron-rich nuclei in the neutron-drip-line region is one of the frontiers of nuclear physics. By directly detecting the neutrons emitted during their decay, the structure and multi-neutron correlations of the nucleus can be investigated, which is not only important for advancing our understanding of the structure and interactions of the finite nuclei, but also helps to gain new insights into the properties of neutron-rich matter.
One essential yet challenging task for multi-neutron detection experiments is to distinguish true multi-neutron events from the background signals (so-called crosstalks). A neural network-based multi-neutron identification algorithm is developed, which significantly improves the four-neutron detection efficiency (>10 times) compared with the traditional algorithm while keeping the energy resolution at a comparable level.
We use the continuum discretized coupled channel method to investigate the breakups of 6Li and 7Li on different target masses when the continuum resonant states are included and excluded in the coupling matrix elements. Our intention is to study the dynamic differences and/or similarities due to their different properties, other than the ground-state binding energy. To this end, keeping the same ground state binding energy, the different calculations will be performed whereas the breakup, fusion and elastic scattering cross sections will be investigated in detail. Our preliminary results reveal that for heavy target the breakup cross sections are enhanced at energies below and suppressed above the Coulomb barrier. On the other hand, for the lighter target small enhancements are observed below the barrier. For the lighter and heavy targets, the fusion cross sections are suppressed below and enhanced at energies above the Coulomb barrier due to these coupling.
Nucleons, fundamental blocks of the world, carry almost all mass of the visible Universe. In Standard Model, nucleons are bound states of quarks and gluons via strong interaction which is described by quantum chromodynamics (QCD). Nucleons are members of a large family of baryons. Non-perturbative features of QCD, confinement and dynamical chiral symmetry broken, are the key to understand baryon properties. Dyson-Schwinger equations (DSEs) are a powerful tool of non-perturbative QCD, which have made numerous progress in recent years. In the talk, I will present latest results of DSEs on baryon properties by rigorously solving a Poincaré-covariant Faddeev equation without a diquark assumption, e.g., mass spectrum from light to heavy systems, nucleon tensor charges, nucleon electromagnetic form factors, and etc.