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

TL;DR

This study investigates potential narrow baryonic pentaquark states in ep collisions at HERA, confirming the Theta(1530) candidate but finding no evidence for other hypothesized pentaquarks in various decay channels.

Contribution

First comprehensive search for multiple pentaquark candidates in ep collisions at HERA, with results supporting Theta(1530) existence and setting limits on others.

Findings

Support for Theta(1530) as a narrow resonance

No evidence for other pentaquark states in studied channels

Constraints on the production of non-observed pentaquarks

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.