Puzzle for the Vector Meson Threshold Photoproduction

by Prof. Igor Strakovsky (George Washington University)

Friday 15 Nov 2024, 10:00 → 12:00 Asia/Shanghai

122 Multidisciplinary Building

Abstract:

High-statistics total cross sections for the vector meson photoproduction at the threshold: gamma p--> omega p, gamma p --> phi p and gamma p --> J/psi p allows one to extract the absolute value of vector meson nucleon scattering length using Vector Meson Dominance model. The ``young’’ vector meson hypothesis may explain the fact that the obtained scattering length value for the nucleon phi-meson compared to the typical hadron size of approximately 1 fm indicates that the proton is more transparent for the phi-meson compared to the omega-meson and is much less transparent than the J/psi-meson. The extended analysis of Upsilon-meson photoproduction using quasi-data from the QCD approach is in perfect agreement with the light-meson findings using experimental data.
Recent high statistical J/psi photoproduction cross sections measured by the GlueX Collaboration allow us to search for the exotic Pc(4312) state observed by the LHCb Collaboration. The fits show that destructive interference involving a S-wave resonance and associated non-resonance background produces a sharp dip structure approximately 77 MeV below the LHCb mass, in the same location as a similar structure is seen in the data. The interference between open charm and gluon exchange may (by some accident) produce a dip, but there is room for resonance.

 

About the Speaker:

Prof. Igor Strakovsky is an experimentalist in fundamental nuclear and particle physics. He received a doctoral degree from the Petersburg Nuclear Physics Institute (PNPI) in 1984 and has been a full research professor at The George Washington University(GW) since 2009. His research centers on hadronic and electromagnetic physics and nuclear structure. Currently, his main experimental focus is on Jefferson Lab, and he is on the PIs of GW's Jefferson Lab Group. In particular, Dr. Strakovsky is a co-spokesperson of the K-Long Facility (KLF) project. KLF can provide a link to understanding the formation of our universe within several microseconds after the Big Bang.

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