Measurement of the Λ b 0 → J/ψ Λ angular distribution and the Λ b 0 polarisation in pp collisions

Journal article

This paper presents an analysis of the Λb0→ J/ψΛ angular distribution and the transverse production polarisation of Λb0 baryons in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The measurements are performed using data corresponding to an integrated luminosity of 4.9 fb−1, collected with the LHCb experiment. The polarisation is determined in a fiducial region of Λb0 transverse momentum and pseudorapidity of 1 < pT< 20 GeV/c and 2 < η < 5, respectively. The data are consistent with Λb0 baryons being produced unpolarised in this region. The parity-violating asymmetry parameter of the Λ → pπ− decay is also determined from the data and its value is found to be consistent with a recent measurement by the BES III collaboration.

Authors: Aaij, R; Abellán Beteta, C; Ackernley, T; Adeva, B; Adinolfi, M

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer
• Journal: Journal of High Energy Physics
• Volume: 2020
• Issue: 6
• Article number: 110
• Publication date: 2020-06-17
• Acceptance date: 2020-05-20
• DOI: 10.1007/jhep06(2020)110
• EISSN: 1029-8479
• ISSN: 1126-6708
• Language: English
• Keywords: Polarization; Flavor physics; Hadron-Hadron scattering (experiments); B physics; Heavy quark production