Evidence for a narrow baryonic state decaying to K(S)(0)p and K-S(0)(p)over-bar in deep inelastic scattering at HERA

Evidence for a narrow baryonic state decaying to K(S)(0)p and K-S(0)(p)over-bar in deep inelastic scattering at HERA

A resonance search has been made in the K0Sp and K0Sp̄ invariant-mass spectrum measured with the ZEUS detector at HERA using an integrated luminosity of 121 pb-1. The search was performed in the central rapidity region of inclusive deep inelastic scattering at an ep centre-of-mass energy of 300-318...

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Bibliographic Details
Main Authors: Chekanov, S, Derrick, M, Loizides, J, Magill, S, Miglioranzi, S, Musgrave, B, Repond, J, Yoshida, R, Mattingly, M, Pavel, N, Antonioli, P, Bari, G, Basile, M, Bellagamba, L, Boscherini, D, Bruni, A, Bruni, G, Romeo, G, Cifarelli, L, Cindolo, F, Contin, A, Corradi, M, De Pasquale, S, Giusti, P, Iacobucci, G
Format: Journal article
Language:English
Published: 2004
Description
Summary:A resonance search has been made in the K0Sp and K0Sp̄ invariant-mass spectrum measured with the ZEUS detector at HERA using an integrated luminosity of 121 pb-1. The search was performed in the central rapidity region of inclusive deep inelastic scattering at an ep centre-of-mass energy of 300-318 GeV for exchanged photon virtuality, Q2, above 1 GeV2. Recent results from fixed-target experiments give evidence for a narrow baryon resonance decaying to K+n and K0Sp, interpreted as a pentaquark. The results presented here support the existence of such state, with a mass of 1521.5±1.5(stat.)+2.8-1.7(syst.) MeV and a Gaussian width consistent with the experimental resolution of 2 MeV. The signal is visible at high Q2 and, for Q2>20 GeV2, contains 221±48 events. The probability of a similar signal anywhere in the range 1500-1560 MeV arising from fluctuations of the background is below 6×10-5. © 2004 Elsevier B.V. All rights reserved.

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