Observations of exotic structures in the J/ψ p channel, which we refer to as charmonium-pentaquark states, in Λ0b → J/ψ K− p decays are presented. The data sample corresponds to an integrated luminosity of 3 fb^−1 acquired with the LHCb detector from 7 and 8 TeV pp collisions. An amplitude analysis of the three-body final state reproduces the two-body mass and angular distributions. To obtain a satisfactory fit of the structures seen in the J/ψ p mass spectrum, it is necessary to include two Breit-Wigner amplitudes that each describe a resonant state. The significance of each of these resonances is more than 9 standard deviations. One has a mass of 4380 ± 8 ± 29 MeV and a width of 205 ± 18 ± 86 MeV, while the second is narrower, with a mass of 4449.8 ± 1.7 ± 2.5 MeV and a width of 39 ± 5 ± 19 MeV. The preferred J^P assignments are of opposite parity, with one state having spin 3/2 and the other 5/2.

Aaij, R., Adeva, B., Adinolfi, M., Affolder, A., Ajaltouni, Z., Akar, S., et al. (2015). Observation of J/ψ p Resonances Consistent with Pentaquark States in Λ0b → J/ψ K− p Decays. PHYSICAL REVIEW LETTERS, 115(7), 1-15 [10.1103/PhysRevLett.115.072001].

Observation of J/ψ p Resonances Consistent with Pentaquark States in Λ0b → J/ψ K− p Decays

Capriotti, L.;CARBONE, ANGELO;FERRARI, FABIO;GALLI, DOMENICO;MUSSINI, MANUEL;PATRIGNANI, CLAUDIA;PERAZZINI, STEFANO;VAGNONI, VINCENZO MARIA;ZANGOLI, MARIA;ZUCCHELLI, STEFANO
2015

Abstract

Observations of exotic structures in the J/ψ p channel, which we refer to as charmonium-pentaquark states, in Λ0b → J/ψ K− p decays are presented. The data sample corresponds to an integrated luminosity of 3 fb^−1 acquired with the LHCb detector from 7 and 8 TeV pp collisions. An amplitude analysis of the three-body final state reproduces the two-body mass and angular distributions. To obtain a satisfactory fit of the structures seen in the J/ψ p mass spectrum, it is necessary to include two Breit-Wigner amplitudes that each describe a resonant state. The significance of each of these resonances is more than 9 standard deviations. One has a mass of 4380 ± 8 ± 29 MeV and a width of 205 ± 18 ± 86 MeV, while the second is narrower, with a mass of 4449.8 ± 1.7 ± 2.5 MeV and a width of 39 ± 5 ± 19 MeV. The preferred J^P assignments are of opposite parity, with one state having spin 3/2 and the other 5/2.
2015
Aaij, R., Adeva, B., Adinolfi, M., Affolder, A., Ajaltouni, Z., Akar, S., et al. (2015). Observation of J/ψ p Resonances Consistent with Pentaquark States in Λ0b → J/ψ K− p Decays. PHYSICAL REVIEW LETTERS, 115(7), 1-15 [10.1103/PhysRevLett.115.072001].
Aaij,R.; Adeva, B.; Adinolfi, M.; Affolder, A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Cartelle, P....espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/515564
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