Observation of a Λb0 − Λ ̄b0 production asymmetry in proton-proton collisions at √s = 7 and 8 TeV

The LHCb collaboration

doi:10.1007/JHEP10(2021)060

Observation of a Λb0 − Λ ̄b0 production asymmetry in proton-proton collisions at √s = 7 and 8 TeV

The LHCb collaboration

Science Park 105
University of Warwick
University of Zurich
University of Liverpool
Universidade de Santiago de Compostela
University of Bristol
Clermont-Auvergne University
University of Michigan, Ann Arbor
Sezione INFN di Milano
University of Cincinnati
Fakultät Physik
University of Dortmund
European Organization for Nuclear Research
SUPA
University of Glasgow
University of Barcelona
Department of Physics and Astronomy
University of Manchester
Petersburg Nuclear Physics Institute (PNPI)
University of Cambridge
Instituto de Biofisica da UFRJ
Université Paris-Saclay
Istituto Nazionale di Fisica Nucleare, Sezione di Firenze
Sezione INFN di Ferrara
University of Heidelberg
Kurchatov Institute
Syracuse University
Yandex School of Data Analysis
Aix-Marseille Université
Institute of Physics
ENAC-IIC-GEL
Centro Brasileiro de Pesquisas Fisicas
Imperial College London
Sezione di Genova
University of Genoa
National University of Science and Technology “MISIS”
RWTH Aachen University
Faculty of Physics and Applied Computer Science
Agh University of Science and Technology Faculty of Computer Science
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa

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

18 Citations (Scopus)

Abstract

This article presents differential measurements of the asymmetry between Λb0 and Λ¯b0 baryon production rates in proton-proton collisions at centre-of-mass energies of s = 7 and 8 TeV collected with the LHCb experiment, corresponding to an integrated luminosity of 3 fb⁻¹. The Λb0 baryons are reconstructed through the inclusive semileptonic decay Λb0 → Λc+μ⁻ν¯ _μX. The production asymmetry is measured both in intervals of rapidity in the range 2.15 < y < 4.10 and transverse momentum in 2 < p_T< 27 GeV/c. The results are found to be incompatible with symmetric production with a significance of 5.8 standard deviations for both s = 7 and 8 TeV data, assuming no CP violation in the decay. There is evidence for a trend as a function of rapidity with a significance of 4 standard deviations. Comparisons to predictions from hadronisation models in Pythia and heavy-quark recombination are provided. This result constitutes the first observation of a particle-antiparticle asymmetry in b-hadron production at LHC energies. [Figure not available: see fulltext.]

Original language	English
Article number	60
Journal	Journal of High Energy Physics
Volume	2021
Issue number	10
DOIs	https://doi.org/10.1007/JHEP10(2021)060
Publication status	Published - 1 Oct 2021

Keywords

B physics
Hadron-Hadron scattering (experiments)
Hard scattering
Heavy quark production
proton-proton scattering

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10.1007/JHEP10(2021)060

Cite this

@article{5f6deb86825d4255915482ae4fd6954a,

title = "Observation of a Λb0 − Λ{\= }b0 production asymmetry in proton-proton collisions at √s = 7 and 8 TeV",

abstract = "This article presents differential measurements of the asymmetry between Λb0 and Λ¯b0 baryon production rates in proton-proton collisions at centre-of-mass energies of s = 7 and 8 TeV collected with the LHCb experiment, corresponding to an integrated luminosity of 3 fb−1. The Λb0 baryons are reconstructed through the inclusive semileptonic decay Λb0 → Λc+μ−ν¯ μX. The production asymmetry is measured both in intervals of rapidity in the range 2.15 < y < 4.10 and transverse momentum in 2 < pT< 27 GeV/c. The results are found to be incompatible with symmetric production with a significance of 5.8 standard deviations for both s = 7 and 8 TeV data, assuming no CP violation in the decay. There is evidence for a trend as a function of rapidity with a significance of 4 standard deviations. Comparisons to predictions from hadronisation models in Pythia and heavy-quark recombination are provided. This result constitutes the first observation of a particle-antiparticle asymmetry in b-hadron production at LHC energies. [Figure not available: see fulltext.]",

keywords = "B physics, Hadron-Hadron scattering (experiments), Hard scattering, Heavy quark production, proton-proton scattering",

author = "\{The LHCb collaboration\} and R. Aaij and Abdelmotteleb, \{A. S.W.\} and \{Abell{\'a}n Beteta\}, C. and T. Ackernley and B. Adeva and M. Adinolfi and H. Afsharnia and Aidala, \{C. A.\} and S. Aiola and Z. Ajaltouni and S. Akar and J. Albrecht and F. Alessio and M. Alexander and \{Alfonso Albero\}, A. and Z. Aliouche and G. Alkhazov and \{Alvarez Cartelle\}, P. and S. Amato and Amey, \{J. L.\} and Y. Amhis and L. An and L. Anderlini and A. Andreianov and M. Andreotti and F. Archilli and A. Artamonov and M. Artuso and K. Arzymatov and E. Aslanides and M. Atzeni and B. Audurier and S. Bachmann and M. Bachmayer and Back, \{J. J.\} and \{Baladron Rodriguez\}, P. and V. Balagura and W. Baldini and \{Baptista Leite\}, J. and Barlow, \{R. J.\} and S. Barsuk and W. Barter and M. Bartolini and F. Baryshnikov and Basels, \{J. M.\} and S. Bashir and G. Bassi and F. Fleuret and E. Maurice and Niel, \{E. M.\}",

note = "Publisher Copyright: {\textcopyright} 2021, The Author(s).",

year = "2021",

month = oct,

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doi = "10.1007/JHEP10(2021)060",

language = "English",

volume = "2021",

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T1 - Observation of a Λb0 − Λ ̄b0 production asymmetry in proton-proton collisions at √s = 7 and 8 TeV

AU - The LHCb collaboration

AU - Aaij, R.

AU - Abdelmotteleb, A. S.W.

AU - Abellán Beteta, C.

AU - Ackernley, T.

AU - Adeva, B.

AU - Adinolfi, M.

AU - Afsharnia, H.

AU - Aidala, C. A.

AU - Aiola, S.

AU - Ajaltouni, Z.

AU - Akar, S.

AU - Albrecht, J.

AU - Alessio, F.

AU - Alexander, M.

AU - Alfonso Albero, A.

AU - Aliouche, Z.

AU - Alkhazov, G.

AU - Alvarez Cartelle, P.

AU - Amato, S.

AU - Amey, J. L.

AU - Amhis, Y.

AU - An, L.

AU - Anderlini, L.

AU - Andreianov, A.

AU - Andreotti, M.

AU - Archilli, F.

AU - Artamonov, A.

AU - Artuso, M.

AU - Arzymatov, K.

AU - Aslanides, E.

AU - Atzeni, M.

AU - Audurier, B.

AU - Bachmann, S.

AU - Bachmayer, M.

AU - Back, J. J.

AU - Baladron Rodriguez, P.

AU - Balagura, V.

AU - Baldini, W.

AU - Baptista Leite, J.

AU - Barlow, R. J.

AU - Barsuk, S.

AU - Barter, W.

AU - Bartolini, M.

AU - Baryshnikov, F.

AU - Basels, J. M.

AU - Bashir, S.

AU - Bassi, G.

AU - Fleuret, F.

AU - Maurice, E.

AU - Niel, E. M.

PY - 2021/10/1

Y1 - 2021/10/1

N2 - This article presents differential measurements of the asymmetry between Λb0 and Λ¯b0 baryon production rates in proton-proton collisions at centre-of-mass energies of s = 7 and 8 TeV collected with the LHCb experiment, corresponding to an integrated luminosity of 3 fb−1. The Λb0 baryons are reconstructed through the inclusive semileptonic decay Λb0 → Λc+μ−ν¯ μX. The production asymmetry is measured both in intervals of rapidity in the range 2.15 < y < 4.10 and transverse momentum in 2 < pT< 27 GeV/c. The results are found to be incompatible with symmetric production with a significance of 5.8 standard deviations for both s = 7 and 8 TeV data, assuming no CP violation in the decay. There is evidence for a trend as a function of rapidity with a significance of 4 standard deviations. Comparisons to predictions from hadronisation models in Pythia and heavy-quark recombination are provided. This result constitutes the first observation of a particle-antiparticle asymmetry in b-hadron production at LHC energies. [Figure not available: see fulltext.]

AB - This article presents differential measurements of the asymmetry between Λb0 and Λ¯b0 baryon production rates in proton-proton collisions at centre-of-mass energies of s = 7 and 8 TeV collected with the LHCb experiment, corresponding to an integrated luminosity of 3 fb−1. The Λb0 baryons are reconstructed through the inclusive semileptonic decay Λb0 → Λc+μ−ν¯ μX. The production asymmetry is measured both in intervals of rapidity in the range 2.15 < y < 4.10 and transverse momentum in 2 < pT< 27 GeV/c. The results are found to be incompatible with symmetric production with a significance of 5.8 standard deviations for both s = 7 and 8 TeV data, assuming no CP violation in the decay. There is evidence for a trend as a function of rapidity with a significance of 4 standard deviations. Comparisons to predictions from hadronisation models in Pythia and heavy-quark recombination are provided. This result constitutes the first observation of a particle-antiparticle asymmetry in b-hadron production at LHC energies. [Figure not available: see fulltext.]

KW - B physics

KW - Hadron-Hadron scattering (experiments)

KW - Hard scattering

KW - Heavy quark production

KW - proton-proton scattering

U2 - 10.1007/JHEP10(2021)060

DO - 10.1007/JHEP10(2021)060

M3 - Article

AN - SCOPUS:85117519560

SN - 1126-6708

VL - 2021

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 10

M1 - 60

ER -

Observation of a Λb0 − Λ ̄b0 production asymmetry in proton-proton collisions at √s = 7 and 8 TeV

Abstract

Keywords

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