An amplitude analysis of B^{-}→J/ψΛp[over ¯] decays is performed using 4400 signal candidates selected on a data sample of pp collisions recorded at center-of-mass energies of 7, 8, and 13 TeV with the LHCb detector, corresponding to an integrated luminosity of 9  fb^{-1}. A narrow resonance in the J/ψΛ system, consistent with a pentaquark candidate with strangeness, is observed with high significance. The mass and the width of this new state are measured to be 4338.2±0.7±0.4  MeV and 7.0±1.2±1.3  MeV, where the first uncertainty is statistical and the second systematic. The spin is determined to be 1/2 and negative parity is preferred. Because of the small Q-value of the reaction, the most precise single measurement of the B^{-} mass to date, 5279.44±0.05±0.07  MeV, is obtained.

Observation of a J/ψΛ Resonance Consistent with a Strange Pentaquark Candidate in B−→J/ψΛ\overline{p} Decays / R. Aaij, A. . .A.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 131:3(2023 Jul 17), pp. 031901.1-031901.11. [10.1103/PhysRevLett.131.031901]

Observation of a J/ψΛ Resonance Consistent with a Strange Pentaquark Candidate in B−→J/ψΛ\overline{p} Decays

M. Lazzaroni;C. Mancuso;D. Marangotto;A. Merli;N. Neri;M. Petruzzo;E. Spadaro Norella;G. Tonani;
2023

Abstract

An amplitude analysis of B^{-}→J/ψΛp[over ¯] decays is performed using 4400 signal candidates selected on a data sample of pp collisions recorded at center-of-mass energies of 7, 8, and 13 TeV with the LHCb detector, corresponding to an integrated luminosity of 9  fb^{-1}. A narrow resonance in the J/ψΛ system, consistent with a pentaquark candidate with strangeness, is observed with high significance. The mass and the width of this new state are measured to be 4338.2±0.7±0.4  MeV and 7.0±1.2±1.3  MeV, where the first uncertainty is statistical and the second systematic. The spin is determined to be 1/2 and negative parity is preferred. Because of the small Q-value of the reaction, the most precise single measurement of the B^{-} mass to date, 5279.44±0.05±0.07  MeV, is obtained.
Settore FIS/01 - Fisica Sperimentale
17-lug-2023
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/1025175
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