Central production of ${\rho }^0$ in $pp$ collisions with single proton diffractive dissociation at the LHC

Abstract

We consider the $pp\to pp{\rho }^0{\pi }^0$ and $pp\to pn{\rho }^0{\pi }^{+}$ processes at LHC energies. Our description is based on the nonperturbative framework of tensor pomeron and tensor reggeon exchanges. We discuss the Drell-Hiida-Deck type mechanism with centrally produced ${\rho }^0$ meson associated with a very forward/backward $\pi N$ system. The considered processes constitute an inelastic (non-exclusive) background to the $pp\to pp{\rho }^0$ reaction in the case when only the centrally produced ${\rho }^0$ meson decaying into ${\pi }^{+}{\pi }^{-}$ is measured, the final state protons are not observed, and only rapidity-gap conditions are checked experimentally. We compare our results for the $\gamma {\pi }^{+}\to {\rho }^0{\pi }^{+}$ reaction with the experimental data obtained by the H1 collaboration at HERA. We present several differential distributions for the $pp\to pn{\rho }^0{\pi }^{+}$ reaction and estimate the size of the proton dissociative background to the exclusive $pp\to pp{\rho }^0$ process. The ratio of integrated cross sections for the inelastic $pp\to pN{\rho }^0\pi$ processes, where $pN{\rho }^0\pi$ stands for $pn{\rho }^0{\pi }^{+}$ plus $pp{\rho }^0{\pi }^0$, to the reference reaction $pp\to pp{\rho }^0$ is of order of (7--10)\%. We present also the ratios of the ${\rho }^0$ rapidity and transverse momentum distributions for the inelastic $pp\to pN{\rho }^0\pi$ versus the elastic $pp\to pp{\rho }^0$ reaction. Our results may be used to investigate the $\gamma \pi \to {\rho }^0\pi$ process at LHC energies.

Comments: 16 pages, 8 figures