Study of narrow baryonic pentaquark candidates with the ZEUS detector at HERA

Abstract

The three pentaquark candidates Theta^+(1530), Xi(1862) and Theta^0_c(3100) have been studied in ep collisions at a centre-of-mass energy sqrt{s}=300-318 GeV using the full luminosity of the HERA-I data. Searches for narrow baryonic states in the decay channels K^0_s p, K^+ p, Xi^- pi^{+-}, anti-XI^+ pi^{+-} and D^{*+-}p^{-+} are reported. The results support the existence of a narrow resonance decaying into K^0_s p and K^0_s anti-p, consistent with the Theta(1530) state. No signals are seen in the K^+ p, Xi^- pi^{+-}, anti-Xi^+ pi^{+-} and D^{*+-}p{-+} channels.