Measurement of the mass and production rate of Xi(-)(b)( )baryons
The first measurement of the production rate of Ξ − b baryons in p p collisions relative to that of Λ 0 b baryons is reported, using data samples collected by the LHCb experiment, and corresponding to integrated luminosities of 1, 2 and 1.6 fb − 1 at √ s = 7 , 8 and 13 TeV, respectively. In the...
| Autores: | , , , , , , , , , , |
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| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2019 |
| País: | España |
| Recursos: | Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya) |
| Repositorio: | Recercat. Dipósit de la Recerca de Catalunya |
| OAI Identifier: | oai:recercat.cat:2445/171232 |
| Acesso em linha: | https://hdl.handle.net/2445/171232 |
| Access Level: | acceso abierto |
| Palavra-chave: | Barions Quarks Gran Col·lisionador d'Hadrons Baryons Large Hadron Collider (France and Switzerland) |
| Resumo: | The first measurement of the production rate of Ξ − b baryons in p p collisions relative to that of Λ 0 b baryons is reported, using data samples collected by the LHCb experiment, and corresponding to integrated luminosities of 1, 2 and 1.6 fb − 1 at √ s = 7 , 8 and 13 TeV, respectively. In the kinematic region 2 < η < 6 and p T < 20 GeV / c , we measure f Ξ − b f Λ 0 b B ( Ξ − b → J / ψ Ξ − ) B ( Λ 0 b → J / ψ Λ ) = ( 10.8 ± 0.9 ± 0.8 ) × 10 − 2 [ √ s = 7 , 8 TeV ], f Ξ − b f Λ 0 b B ( Ξ − b → J / ψ Ξ − ) B ( Λ 0 b → J / ψ Λ ) = ( 13.1 ± 1.1 ± 1.0 ) × 10 − 2 [ √ s = 13 TeV ], where f Ξ − b and f Λ 0 b are the fragmentation fractions of b quarks into Ξ − b and Λ 0 b baryons, respectively; B represents branching fractions; and the uncertainties are due to statistical and experimental systematic sources. The values of f Ξ − b / f Λ 0 b are obtained by invoking SU(3) symmetry in the Ξ − b → J / ψ Ξ − and Λ 0 b → J / ψ Λ decays. Production asymmetries between Ξ − b and ¯ Ξ + b baryons are also reported. The mass of the Ξ − b baryon is also measured relative to that of the Λ 0 b baryon, from which it is found that m ( Ξ − b ) = 5796.70 ± 0.39 ± 0.15 ± 0.17 MeV / c 2 , where the last uncertainty is due to the precision on the known Λ 0 b mass. This result represents the most precise determination of the Ξ − b mass. |
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