Heavy quark probes

Another approach to study the structure of the hadronic matter is via the study of heavy quarks. Thanks to its large mass, the dynamics of the heavy quark is controlled by pertrubative QCD, and presents a clean test of the gluonic content of the hadron. For this reason, the mesons containing heavy quarks (quarkonia and open-flavour mesons) since their discovery have been extensively used as a probe of hadronic matter formed in proton-nuclear and heavy ion collisions. Recently we solved a long standing puzzle of large suppression of ψ(2S) meson in pA collisions, and described in the same framework the suppression of different quarkonia (J/ψ, ψ(2S), Υ) in a wide energy range, from RHIC to LHC. Now we are working on extension of our framework to the case of heavy ion collisions at LHC, which presents a new challenge in view of Quark-Gluon Plasma formation at later stages of heavy ion collisions.

Exotic baryons

The interest to the heavy quark physics has recently increased after discovery of tetra- and pentaquarks containing heavy quarks. Though a few exotic baryons have been observed, it is expected that the list of exotic hadrons could be quite extensive in view of possible combinations of heavy and light quarks. My research in this area is focused on understanding the structure and production mechanisms of exotic baryons. For the case of pentaquarks, recently we suggested a novel production mechanism in proton-nucleus collisions. Compared to the original mechanism via Λ_b decays, where pentaquarks were discovered, the suggested mechanism does not possess electroweak intermediaries and for this reason has considerably larger cross-section. Angular distribution of the produced pentaquarks could give a comprehensive information about the cc dipole inside the pentaquark. The suggested process can be studied both in collider as well as in fixed-target experiments, and additionally allows to check the existence of partners of pentaquarks from flavour multiplets predicted in various models. Now we are working on extension of the suggested framework to other production mechanisms.

Selected papers

1. ``GPDs from charged current meson production in ep experiments'', M. Siddikov and I. Schmidt, arXiv:1709.01405 [hep-ph].
2. ``Suppression versus enhancement of heavy quarkonia in pA collisions'', B. Z. Kopeliovich, I. Schmidt and M. Siddikov, Phys. Rev. C 95, no. 6, 065203 (2017)[arXiv:1701.07134 [hep-ph]].
3. ``Loop corrections to pion and kaon neutrino production'', M. Siddikov and I. Schmidt, Phys. Rev. D 95, no. 1, 013004 (2017) [arXiv:1611.07294 [hep-ph]].
4. ``Production of pentaquarks in pA-collisions'', I. Schmidt and M. Siddikov. Phys. Rev. D 93, no. 9, 094005 (2016)[arXiv:1601.05621 [hep-ph]].
5. ``Survival of charmonia in a hot environment'', B. Z. Kopeliovich, I. K. Potashnikova, I. Schmidt and M. Siddikov, Phys. Rev. C 91, no. 2, 024911 (2015)[arXiv:1409.5147 [hep-ph]].
6. ``Higher-twist contributions to neutrino-production of pions'', B. Z. Kopeliovich, I. Schmidt and M. Siddikov, Phys. Rev. D 89, no. 5, 053001 (2014)[arXiv:1401.1547 [hep-ph]].
7. ``Bethe-Heitler type radiative corrections to deeply virtual neutrino production of mesons'', B. Z. Kopeliovich, I. Schmidt and M. Siddikov, Phys. Rev. D 87, no. 3, 033008 (2013) [arXiv:1301.7014 [hep-ph]].
8. ``Flavor structure of generalized parton distributions from neutrino experiments'', B. Z. Kopeliovich, I. Schmidt and M. Siddikov, Phys. Rev. D 86, 113018 (2012)[arXiv:1210.4825 [hep-ph]]

Publication list in Inspire Hep