Measurement of the mass and production rate of Ξb- baryons

LHCb Collaboration

doi:10.1103/PhysRevD.99.052006

Measurement of the mass and production rate of Ξ_b^- baryons

LHCb Collaboration

Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

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Abstract

The first measurement of the production rate of Ξ_b^- baryons in pp collisions relative to that of Λ_b⁰ 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 pT<20 GeV/c, we measure

(f_Ξb-/f_Λb0)(ℬ(Ξ_b^-→J/ψΞ^-)/ℬ(Λ_b⁰→J/ψΛ))=(10.8±0.9±0.8)×10^-2 [√s=7,8 TeV],
(f_Ξb-/f_Λb0)(ℬ(Ξ_b^-→J/ψΞ^-)/ℬ(Λ_b⁰→J/ψΛ))=(13.1±1.1±1.0)×10^-2 [√s=13 TeV],

where f_Ξb- and f_Λb0 are the fragmentation fractions of b quarks into Ξ_b^- and Λ_b⁰ baryons, respectively; B represents branching fractions; and the uncertainties are due to statistical and experimental systematic sources. The values of f_Ξb-/f_Λb0 are obtained by invoking SU(3) symmetry in the Ξ_b^-→J/ψΞ^- and Λ_b⁰→J/ψΛ 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_b⁰ baryon, from which it is found that m(Ξ_b^-)=5796.70±0.39±0.15±0.17 MeV/c², where the last uncertainty is due to the precision on the known Λ_b⁰ mass. This result represents the most precise determination of the Ξ_b^- mass.

Original language	English
Article number	052006
Number of pages	13
Journal	Physical Review D
Volume	99
Issue number	5
DOIs	https://doi.org/10.1103/PhysRevD.99.052006
Publication status	Published - 22 Mar 2019

ASJC Scopus subject areas

Physics and Astronomy (miscellaneous)

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10.1103/PhysRevD.99.052006

Aaij_et_al_Measurement_of_the_mass_and_production_Physical_Review_D_2019
Checked for eligibility: 14/05/2019 DOI: https://doi.org/10.1103/PhysRevD.99.052006
Final published version, 345 KBLicence: Creative Commons: Attribution (CC BY)

Cite this

@article{cabee3383b9342dd95ea817d83a1c56f,

title = "Measurement of the mass and production rate of Ξb- baryons",

abstract = "The first measurement of the production rate of Ξb- baryons in pp collisions relative to that of Λb0 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 pT<20 GeV/c, we measure (fΞb-/fΛb0)(ℬ(Ξb-→J/ψΞ-)/ℬ(Λb0→J/ψΛ))=(10.8±0.9±0.8)×10-2 [√s=7,8 TeV],(fΞb-/fΛb0)(ℬ(Ξb-→J/ψΞ-)/ℬ(Λb0→J/ψΛ))=(13.1±1.1±1.0)×10-2 [√s=13 TeV], where fΞb- and fΛb0 are the fragmentation fractions of b quarks into Ξb- and Λb0 baryons, respectively; B represents branching fractions; and the uncertainties are due to statistical and experimental systematic sources. The values of fΞb-/fΛb0 are obtained by invoking SU(3) symmetry in the Ξb-→J/ψΞ- and Λb0→J/ψΛ decays. Production asymmetries between Ξb- and Ξb+ baryons are also reported. The mass of the Ξb- baryon is also measured relative to that of the Λb0 baryon, from which it is found that m(Ξb-)=5796.70±0.39±0.15±0.17 MeV/c2, where the last uncertainty is due to the precision on the known Λb0 mass. This result represents the most precise determination of the Ξb- mass.",

author = "{LHCb Collaboration} and R. Aaij and {Abell{\'a}n Beteta}, C. and B. Adeva and M. Adinolfi and Aidala, {C. A.} and Z. Ajaltouni and S. Akar and P. Albicocco and J. Albrecht and F. Alessio and M. Alexander and {Alfonso Albero}, A. and G. Alkhazov and {Alvarez Cartelle}, P. and Alves, {A. A.} and S. Amato and S. Amerio and Y. Amhis and L. An and L. Anderlini and G. Andreassi and M. Andreotti and Andrews, {J. E.} and F. Archilli and P. D'Argent and {Arnau Romeu}, J. and A. Artamonov and M. Artuso and K. Arzymatov and E. Aslanides and M. Atzeni and B. Audurier and S. Bachmann and Back, {J. J.} and S. Baker and S. Bifani and R. Calladine and G. Chatzikonstantinidis and N. Farley and P. Griffith and P. Ilten and C. Lazzeroni and L. Pescatore and J. Plews and D. Popov and A. Sergi and Slater, {M. W.} and Watson, {N. K.} and T. Williams and Zarebski, {K. A.}",

year = "2019",

month = mar,

day = "22",

doi = "10.1103/PhysRevD.99.052006",

language = "English",

volume = "99",

journal = "Physical Review D",

issn = "2470-0010",

publisher = "American Physical Society (APS)",

number = "5",

}

TY - JOUR

T1 - Measurement of the mass and production rate of Ξb- baryons

AU - LHCb Collaboration

AU - Aaij, R.

AU - Abellán Beteta, C.

AU - Adeva, B.

AU - Adinolfi, M.

AU - Aidala, C. A.

AU - Ajaltouni, Z.

AU - Akar, S.

AU - Albicocco, P.

AU - Albrecht, J.

AU - Alessio, F.

AU - Alexander, M.

AU - Alfonso Albero, A.

AU - Alkhazov, G.

AU - Alvarez Cartelle, P.

AU - Alves, A. A.

AU - Amato, S.

AU - Amerio, S.

AU - Amhis, Y.

AU - An, L.

AU - Anderlini, L.

AU - Andreassi, G.

AU - Andreotti, M.

AU - Andrews, J. E.

AU - Archilli, F.

AU - D'Argent, P.

AU - Arnau Romeu, J.

AU - Artamonov, A.

AU - Artuso, M.

AU - Arzymatov, K.

AU - Aslanides, E.

AU - Atzeni, M.

AU - Audurier, B.

AU - Bachmann, S.

AU - Back, J. J.

AU - Baker, S.

AU - Bifani, S.

AU - Calladine, R.

AU - Chatzikonstantinidis, G.

AU - Farley, N.

AU - Griffith, P.

AU - Ilten, P.

AU - Lazzeroni, C.

AU - Pescatore, L.

AU - Plews, J.

AU - Popov, D.

AU - Sergi, A.

AU - Slater, M. W.

AU - Watson, N. K.

AU - Williams, T.

AU - Zarebski, K. A.

PY - 2019/3/22

Y1 - 2019/3/22

N2 - The first measurement of the production rate of Ξb- baryons in pp collisions relative to that of Λb0 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 pT<20 GeV/c, we measure (fΞb-/fΛb0)(ℬ(Ξb-→J/ψΞ-)/ℬ(Λb0→J/ψΛ))=(10.8±0.9±0.8)×10-2 [√s=7,8 TeV],(fΞb-/fΛb0)(ℬ(Ξb-→J/ψΞ-)/ℬ(Λb0→J/ψΛ))=(13.1±1.1±1.0)×10-2 [√s=13 TeV], where fΞb- and fΛb0 are the fragmentation fractions of b quarks into Ξb- and Λb0 baryons, respectively; B represents branching fractions; and the uncertainties are due to statistical and experimental systematic sources. The values of fΞb-/fΛb0 are obtained by invoking SU(3) symmetry in the Ξb-→J/ψΞ- and Λb0→J/ψΛ decays. Production asymmetries between Ξb- and Ξb+ baryons are also reported. The mass of the Ξb- baryon is also measured relative to that of the Λb0 baryon, from which it is found that m(Ξb-)=5796.70±0.39±0.15±0.17 MeV/c2, where the last uncertainty is due to the precision on the known Λb0 mass. This result represents the most precise determination of the Ξb- mass.

AB - The first measurement of the production rate of Ξb- baryons in pp collisions relative to that of Λb0 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 pT<20 GeV/c, we measure (fΞb-/fΛb0)(ℬ(Ξb-→J/ψΞ-)/ℬ(Λb0→J/ψΛ))=(10.8±0.9±0.8)×10-2 [√s=7,8 TeV],(fΞb-/fΛb0)(ℬ(Ξb-→J/ψΞ-)/ℬ(Λb0→J/ψΛ))=(13.1±1.1±1.0)×10-2 [√s=13 TeV], where fΞb- and fΛb0 are the fragmentation fractions of b quarks into Ξb- and Λb0 baryons, respectively; B represents branching fractions; and the uncertainties are due to statistical and experimental systematic sources. The values of fΞb-/fΛb0 are obtained by invoking SU(3) symmetry in the Ξb-→J/ψΞ- and Λb0→J/ψΛ decays. Production asymmetries between Ξb- and Ξb+ baryons are also reported. The mass of the Ξb- baryon is also measured relative to that of the Λb0 baryon, from which it is found that m(Ξb-)=5796.70±0.39±0.15±0.17 MeV/c2, where the last uncertainty is due to the precision on the known Λb0 mass. This result represents the most precise determination of the Ξb- mass.

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U2 - 10.1103/PhysRevD.99.052006

DO - 10.1103/PhysRevD.99.052006

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