Speaker
Description
We study the production of $2\pi^+2\pi^-$ in ultraperipheral heavy-ion collisions at RHIC and LHC energies. The recent H1 preliminary data [1] are utilized to improve the description of the poorly known $\gamma p \to 4\pi^\pm p$ process. Predictions for photon-nucleus interactions were calculated for various excited states of $\rho$ meson. We will present an agreement of theory with the available STAR data at RHIC [2]. The comparison of $2\pi^+2\pi^-$ invariant mass spectrum and nuclear total cross section shows that $\rho(1570)$ plays a crucial role [3] in correctly describing existing experimental data. STAR data for the four-pion state were interpreted as the decay of $\rho(1700)$ resonance. New H1 data allows us to verify this reasoning. Nuclear predictions will also be given for LHC energy at the central and forward regions of rapidities.
[1] H1 Collaboration, S. Schmitt, 26th International Workshop on Deep
Inelastic Scattering and Related Subjects (DIS 2018): Port Island, Kobe,
Japan, April 16-20, 2018,
[2] STAR Collaboration, B.I. Abelev et al., Phys. Rev. C81 (2010) 044901,
[3] M. Kłusek-Gawenda and J. Daniel Tapia Takaki, Acta Phys. Polon. B51
(2020) 6, 1393.
