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Title: Observation of J/ψp Resonances Consistent with Pentaquark States in Λ0b→J/ψK−p Decays
Author: Badalov, Alexey
Calvo Gómez, Míriam
Garrido Beltrán, Lluís
Gascón Fora, David
Graciani Díaz, Ricardo
Graugés Pous, Eugeni
Marin Benito, Carla
Picatoste Olloqui, Eduardo
Rives Molina, Vicente José
Vilasis-Cardona, Xavier
LHCb Collaboration
Keywords: Física de partícules
Particle physics
Issue Date: 12-Aug-2015
Publisher: American Physical Society
Abstract: Observations of exotic structures in the J / ψ p channel, which we refer to as charmonium-pentaquark states, in Λ 0 b → 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 p p 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 .
Note: Reproducció del document publicat a:
It is part of: Physical Review Letters, 2015, vol. 115, num. 7, p. 072001
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ISSN: 0031-9007
Appears in Collections:Articles publicats en revistes (Electrònica)
Articles publicats en revistes (Física Quàntica i Astrofísica)

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