Search for a narrow baryonic state decaying to $p{K}_S^0$ and $\bar{p}{K}_S^0$ in deep inelastic scattering at HERA

Abstract

A search for a narrow baryonic state in the $p{K}_S^0$ and $\bar{p}{K}_S^0$ system has been performed in $ep$ collisions at HERA with the ZEUS detector using an integrated luminosity of 358 pb${}^{-1}$ taken in 2003-2007. The search was performed with deep inelastic scattering events at an $ep$ centre-of-mass energy of 318 GeV for exchanged photon virtuality, $Q^2$, between 20 and 100 $\mathrm{Ge}{\mathrm{V}}^2$. Contrary to evidence presented for such a state around 1.52 GeV in a previous ZEUS analysis using a sample of 121 pb${}^{-1}$ taken in 1996-2000, no resonance peak was found in the $p(\bar{p})K_S^0$ invariant-mass distribution in the range 1.45-1.7 GeV. Upper limits on the production cross section are set.

Comments: 16 pages, 4 figures, accepted by Phys. Lett. B. Minor changes from journal reviewing process, including a small correction to figure 4