Enhanced Production of Λ_{b}^{0} Baryons in High-Multiplicity pp Collisions at sqrt[s]=13  TeV

• Published in: Physical review letters Vol. 132; no. 8; p. 081901
• Main Authors: Aaij, R, Abdelmotteleb, A S W, Abellan Beteta, C, Abudinén, F, Ackernley, T, Adeva, B, Adinolfi, M, Adlarson, P, Agapopoulou, C, Aidala, C A, Ajaltouni, Z, Akar, S, Akiba, K, Albicocco, P, Albrecht, J, Alessio, F, Alexander, M, Alfonso Albero, A, Aliouche, Z, Alvarez Cartelle, P, Amalric, R, Amato, S, Amey, J L, Amhis, Y, An, L, Anderlini, L, Andersson, M, Andreianov, A, Andreola, P, Andreotti, M, Andreou, D, Anelli, A A, Ao, D, Archilli, F, Argenton, M, Arguedas Cuendis, S, Artamonov, A, Artuso, M, Aslanides, E, Atzeni, M, Audurier, B, Bacher, D, Bachiller Perea, I, Bachmann, S, Bachmayer, M, Back, J J, Bailly-Reyre, A, Baladron Rodriguez, P, Balagura, V, Baldini, W, Baptista de Souza Leite, J, Barbetti, M, Barbosa, I R, Barlow, R J, Barsuk, S, Barter, W, Bartolini, M, Baryshnikov, F, Basels, J M, Bassi, G, Batsukh, B, Battig, A, Bay, A, Beck, A, Becker, M, Bedeschi, F, Bediaga, I B, Beiter, A, Belin, S, Bellee, V, Belous, K, Belov, I, Belyaev, I, Benane, G, Bencivenni, G, Ben-Haim, E, Berezhnoy, A, Berkey, J L M, Bernet, R, Bernet Andres, S, Bernstein, H C, Bertella, C, Bertolin, A, Betancourt, C, Betti, F, Bex, J, Bezshyiko, Ia, Bhom, J, Bieker, M S, Biesuz, N V, Billoir, P, Biolchini, A, Birch, M, Bishop, F C R, Bitadze, A, Bizzeti, A, Blago, M P, Blake, T, Blanc, F, Blank, J E
• Format: Journal Article
• Language: English
• Published: United States 23-02-2024
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.132.081901

The production rate of Λ_{b}^{0} baryons relative to B^{0} mesons in pp collisions at a center-of-mass energy sqrt[s]=13  TeV is measured by the LHCb experiment. The ratio of Λ_{b}^{0} to B^{0} production cross sections shows a significant dependence on both the transverse momentum and the measured charged-particle multiplicity. At low multiplicity, the ratio measured at LHCb is consistent with the value measured in e^{+}e^{-} collisions, and increases by a factor of ∼2 with increasing multiplicity. At relatively low transverse momentum, the ratio of Λ_{b}^{0} to B^{0} cross sections is higher than what is measured in e^{+}e^{-} collisions, but converges with the e^{+}e^{-} ratio as the momentum increases. These results imply that the evolution of heavy b quarks into final-state hadrons is influenced by the density of the hadronic environment produced in the collision. Comparisons with several models and implications for the mechanisms enforcing quark confinement are discussed.