A resonance search has been made in the K0s p and K0s pbar 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 K0s p, 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 6x10^{-5}.

S. CHEKANOV, M.D., NIAK, ., ARNECKI, M.A. (2004). Evidence for a narrow baryonic state decaying to K0s-(anti)proton in deep inelastic scattering at HERA. PHYSICS LETTERS. SECTION B, 591, 7-22 [10.1016/j.physletb.2004.04.024].

Evidence for a narrow baryonic state decaying to K0s-(anti)proton in deep inelastic scattering at HERA

BASILE, MAURIZIO;CIFARELLI, LUISA;CONTIN, ANDREA;PALMONARI, FEDERICO;RINALDI, LORENZO;SARTORELLI, GABRIELLA;ZICHICHI, ANTONINO;
2004

Abstract

A resonance search has been made in the K0s p and K0s pbar 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 K0s p, 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 6x10^{-5}.
2004
S. CHEKANOV, M.D., NIAK, ., ARNECKI, M.A. (2004). Evidence for a narrow baryonic state decaying to K0s-(anti)proton in deep inelastic scattering at HERA. PHYSICS LETTERS. SECTION B, 591, 7-22 [10.1016/j.physletb.2004.04.024].
S. CHEKANOV, M. DERRICK, S. MAGILL, S. MIGLIORANZI, , B. MUSGRAVE, J. REPOND, R. YOSHIDA, M.C.K. MATTINGLY, N. PAVEL, A.G. YAGÜES MOLINA, P. ANTONIOLI...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/20312
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