Nuclear Physics Seminar

Abstract: The production of eta_c in diffractive ep and eA collisions has been suggested as a golden probe of the C-odd QCD interaction, the odderon. Previous studies of this process have considered a linearised Bartels-Kwiecinski-Praszalowicz odderon [1-3], which is appropriate in the dilute regime where the x region probed in the proton is not too small. In this work [4], we explore this process in the dense regime, i.e., at low-x values in the proton or in large nuclei where effects of gluon saturation may become important. We treat the energy evolution of the odderon using the running coupling Balitsky-Kovchegov equation which incorporates saturation effects and present numerical estimates for eta_c production in diffractive ep and eA (Au, Cu, Al) at the Electron-Ion Collider (EIC). As the initial condition for odderon evolution, we adopt a Jeon-Venugopalan model [5] based odderon, with the overall normalisation being fixed by a group theoretic constraint [6,7] which gives us an upper bound for the size of the odderon, as well as the cross-section. By studying the dependence of eta_c production on different kinematics and nuclear size, and the relative sizes of the QCD and QED contributions, we aim to identify the ideal scenario to get a signal for the odderon at the EIC.


References:
1) R. Engel, D. Y. Ivanov, R. Kirschner, and L. Szymanowski, Eur. Phys. J. C 4, 93 (1998)
2) J. Czyzewski, J. Kwiecinski, L. Motyka, and M. Sadzikowski, Phys. Lett. B 398, 400 (1997)
3) A. Dumitru and T. Stebel, Phys. Rev. D 99, 094038 (2019)
4) S. Benic, D. Horvatic, A. Kaushik, and E. Vivoda, in preparation
5) S. Jeon and R. Venugopalan, Phys. Rev. D 71, 125003 (2005)
6) T. Lappi, A. Ramnath, K. Rummukainen, and H. Weigert, Phys. Rev. D 94, 054014 (2016)
7) N. Kaiser, Journal of Physics A: Mathematical and General 39, 15287 (2006)