Speaker
Summary
We study [1] the suppressions of high transverse momentum single hadron and dihadron productions in high-energy heavy-ion collisions based on the framework of a next-to-leading-order perturbative QCD parton model combined with the higher-twist energy loss formalism [2,3]. Our model can provide a consistent description for the nuclear modification factors of single hadron $R_{AA}$ and dihadron $I_{AA}$ in central and non-central nucleus-nucleus collisions at RHIC and the LHC energies.
We quantitatively extract the value of jet quenching parameter $\hat{q}$ via a global $\chi^2$ analysis, and obtain the scaled jet quenching parameter ${\hat{q}}/{T^3} = 4.1 \sim 4.4$ at $T = 378$~MeV for 0.2 TeV Au+Au collisions and ${\hat{q}}/{T^3} = 2.6 \sim 3.3$ at $T = 486$~MeV for 2.76 TeV Pb+Pb collisions, which are consistent with the results from JET Collaboration [4]. We also get the ${\hat{q}}/{T^3} = 2.5 $ at $T=516$~MeV for 5.02 TeV Pb+Pb collisions, ${\hat{q}}/{T^3} = 3.5$ at $T= 469$~MeV for 5.44 TeV Xe+Xe collisions only via single hadron productions and provide the predictions for the dihadron $I_{AA}$ of these two collisions. The above numerical analysis shows that ${\hat{q}}/{T^3}$ has some temperature dependence: it decreases as one increases the temperature, which can be understood as decreasing jet-medium interaction strength with increasing temperature.
Here are some other interesting results that the dihadron $I_{AA}$ are typically larger than single hadron $R_{AA}$ given the same nucleus-nucleus collision conditions and the values of $I_{AA}$ also increase as one increases the trigger hadron $p_T$. These results can be explained by that high $p_T$ single hadrons mainly come from surface bias emission jets, while high $p_T$ dihadrons come from a combination of surfacial and tangential jets as well as punching-through jets [5,6]. And with increasing trigger hadron $p_T$, the contribution from punching-through jets increases [7]. On average in a A + A event, the total energy loss for jets in the surface bias case is larger than in the case with punching-through jets.
References
[1] M. Xie, S. Y. Wei, G. Y. Qin and H. Z. Zhang, arXiv:1901.04155 [hep-ph].
[2] H. Zhang, J. F. Owens, E. Wang and X. N. Wang, Phys. Rev. Lett. 103, 032302 (2009).
[3] X. f. Guo and X. N. Wang, Phys. Rev. Lett. 85, 3591 (2000).
[4] K. M. Burke et al. [JET Collaboration], Phys. Rev. C 90, no. 1, 014909 (2014).
[5] H. Zhang, J. F. Owens, E. Wang and X. N. Wang, Phys. Rev. Lett. 98, 212301 (2007).
[6] J. G. Milhano and K. C. Zapp, Eur. Phys. J. C 76, no. 5, 288 (2016).
[7] H. z. Zhang, J. F. Owens, E. Wang and X.-N. Wang, J. Phys. G 35, 104067 (2008).
