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-fΛb0B(Ξb-→J/ψΞ-)B(Λb0→J/ψΛ)=(10.8±0.9±0.8)×10-2 [s=7,8 TeV], fΞb-fΛb0B(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.

Original language	English
Article number	052006
Journal	Physical Review D
Volume	99
Issue number	5
DOIs	https://doi.org/10.1103/PhysRevD.99.052006
Publication status	Published - 1 Mar 2019

ASJC Scopus subject areas

Physics and Astronomy (miscellaneous)

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@article{741bee5d2c93423eaadf5f6e08386d96,

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-fΛb0B(Ξb-→J/ψΞ-)B(Λb0→J/ψΛ)=(10.8±0.9±0.8)×10-2 [s=7,8 TeV], fΞb-fΛb0B(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 V. Balagura and W. Baldini and A. Baranov and Barlow, {R. J.} and Barrand, {G. C.} and S. Barsuk and W. Barter and M. Bartolini and F. Baryshnikov and V. Batozskaya and B. Batsukh and A. Battig and V. Battista and A. Petrov and S. Strokov",

note = "Funding Information: We thank M. Voloshin for interesting and helpful discussions on theoretical aspects of this work. We express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); MOST and NSFC (China); CNRS/IN2P3 (France); BMBF, DFG and MPG (Germany); INFN (Italy); NWO (Netherlands); MNiSW and NCN (Poland); MEN/IFA (Romania); MSHE (Russia); MinECo (Spain); SNSF and SER (Switzerland); NASU (Ukraine); STFC (United Kingdom); and NSF (USA). We acknowledge the computing resources that are provided by CERN, IN2P3 (France), KIT and DESY (Germany), INFN (Italy), SURF (Netherlands), PIC (Spain), GridPP (United Kingdom), RRCKI and Yandex LLC (Russia), CSCS (Switzerland), IFIN-HH (Romania), CBPF (Brazil), PL-GRID (Poland) and OSC (USA). We are indebted to the communities behind the multiple open-source software packages on which we depend. Individual groups or members have received support from AvH Foundation (Germany); EPLANET, Marie Sk{\l}odowska-Curie Actions and ERC (European Union); ANR, Labex P2IO and OCEVU, and R{\'e}gion Auvergne-Rh{\^o}ne-Alpes (France); Key Research Program of Frontier Sciences of CAS, CAS PIFI, and the Thousand Talents Program (China); RFBR, RSF and Yandex LLC (Russia); GVA, XuntaGal and GENCAT (Spain); the Royal Society and the Leverhulme Trust (United Kingdom); Laboratory Directed Research and Development program of LANL (USA).",

year = "2019",

month = mar,

day = "1",

doi = "10.1103/PhysRevD.99.052006",

language = "English",

volume = "99",

journal = "Physical Review D",

issn = "2470-0010",

publisher = "American Physical Society",

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 - Balagura, V.

AU - Baldini, W.

AU - Baranov, A.

AU - Barlow, R. J.

AU - Barrand, G. C.

AU - Barsuk, S.

AU - Barter, W.

AU - Bartolini, M.

AU - Baryshnikov, F.

AU - Batozskaya, V.

AU - Batsukh, B.

AU - Battig, A.

AU - Battista, V.

AU - Petrov, A.

AU - Strokov, S.

N1 - Funding Information: We thank M. Voloshin for interesting and helpful discussions on theoretical aspects of this work. We express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); MOST and NSFC (China); CNRS/IN2P3 (France); BMBF, DFG and MPG (Germany); INFN (Italy); NWO (Netherlands); MNiSW and NCN (Poland); MEN/IFA (Romania); MSHE (Russia); MinECo (Spain); SNSF and SER (Switzerland); NASU (Ukraine); STFC (United Kingdom); and NSF (USA). We acknowledge the computing resources that are provided by CERN, IN2P3 (France), KIT and DESY (Germany), INFN (Italy), SURF (Netherlands), PIC (Spain), GridPP (United Kingdom), RRCKI and Yandex LLC (Russia), CSCS (Switzerland), IFIN-HH (Romania), CBPF (Brazil), PL-GRID (Poland) and OSC (USA). We are indebted to the communities behind the multiple open-source software packages on which we depend. Individual groups or members have received support from AvH Foundation (Germany); EPLANET, Marie Skłodowska-Curie Actions and ERC (European Union); ANR, Labex P2IO and OCEVU, and Région Auvergne-Rhône-Alpes (France); Key Research Program of Frontier Sciences of CAS, CAS PIFI, and the Thousand Talents Program (China); RFBR, RSF and Yandex LLC (Russia); GVA, XuntaGal and GENCAT (Spain); the Royal Society and the Leverhulme Trust (United Kingdom); Laboratory Directed Research and Development program of LANL (USA).

PY - 2019/3/1

Y1 - 2019/3/1

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-fΛb0B(Ξb-→J/ψΞ-)B(Λb0→J/ψΛ)=(10.8±0.9±0.8)×10-2 [s=7,8 TeV], fΞb-fΛb0B(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-fΛb0B(Ξb-→J/ψΞ-)B(Λb0→J/ψΛ)=(10.8±0.9±0.8)×10-2 [s=7,8 TeV], fΞb-fΛb0B(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.

UR - http://www.scopus.com/inward/record.url?scp=85064410812&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85064410812&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.99.052006

DO - 10.1103/PhysRevD.99.052006

M3 - Article

AN - SCOPUS:85064410812

VL - 99

JO - Physical Review D

JF - Physical Review D

SN - 2470-0010

IS - 5

M1 - 052006

ER -