Observation of a Λ0 b − Λ0b production asymmetry in proton-proton collisions at √s = 7 and 8 TeV

LHCb collaboration, R.H. O'Neil

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

This article presents differential measurements of the asymmetry between Λ0
b and Λ0 b 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 Λ0b baryons are reconstructed through the inclusive semileptonic decay Λ0b → Λ+c μ−νμX. 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.
Original languageEnglish
Article number60
Pages (from-to)1-36
Number of pages36
Journal Journal of High Energy Physics
Issue number10
Publication statusPublished - 7 Oct 2021

Keywords / Materials (for Non-textual outputs)

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


Dive into the research topics of 'Observation of a Λ0 b − Λ0b production asymmetry in proton-proton collisions at √s = 7 and 8 TeV'. Together they form a unique fingerprint.

Cite this