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LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., & Ruiz Vidal, J. (2022). Evidence for a New Structure in the J/psi p and J/psi(p)over-bar Systems in B-s(0) -> J/psi p(p)over-bar Decays. Phys. Rev. Lett., 128(6), 062001–11pp.
Abstract: An amplitude analysis of flavor-untagged B-s(0) -> J=psi p (p) over bar decays is performed using a sample of 797 +/- 31 decays reconstructed with the LHCb detector. The data, collected in proton-proton collisions between 2011 and 2018, correspond to an integrated luminosity of 9 fb(-1). Evidence for a new structure in the J=psi p and J=psi(p) over bar systems with a mass of 4337(-4-2)(+7+2) MeV and a width of 29(-12-14)(+26+14) MeV is found, where the first uncertainty is statistical and the second systematic, with a significance in the range of 3.1 to 3.7 sigma, depending on the assigned J(P) hypothesis.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2018). Evidence for an etac(1S)pi- resonance in B0 etac(1S)K+pi- decays. Eur. Phys. J. C, 78(12), 1019–23pp.
Abstract: A Dalitz plot analysis of /30 ric(1S)K+7decays is performed using data samples of pp collisions collected with the LHCb detector at centre -of -mass energies of./7 = 7, 8 and 13 TeV, corresponding to a total integrated luminosity of 4.7 fb-1. A satisfactory description of the data is obtained when including a contribution representing an exotic qc (1 S).7-- resonant state. The significance of this exotic resonance is more than three standard deviations, while its mass and width are 4096 20 is MeV and 152 +58 -P6 MeV, respectively. The spin -parity assignments JP = 0+ and JP = 1- are both consistent with the data. In addition, the first measurement of the B -> ric(1S)K+71-branching fraction is performed and gives B(B -> = (5.73 0.24 0.13 0.66) x 10-4, where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Evidence for CP Violation in B+ -> p(p)over-barK(+) Decays. Phys. Rev. Lett., 113(14), 141801–9pp.
Abstract: Three-body B+ -> p (p) over barK(+) and B+ -> p (p) over bar pi(+) decays are studied using a data sample corresponding to an integrated luminosity of 3.0 fb(-1) collected by the LHCb experiment in proton-proton collisions at center-of-mass energies of 7 and 8 TeV. Evidence of CP violation in the B+ -> p (p) over barK(+) decay is found in regions of the phase space, representing the first measurement of this kind for a final state containing baryons. Measurements of the forward-backward asymmetry of the light meson in the p (p) over bar rest frame yield A(FB)(p (p) over barK(+), m(p (p) over bar) < 2.85 GeV/c(2)) = 0.495 +/- 0.012 (stat) +/- 0.007 (syst) and A(FB)(p<(p)over bar>pi(+), m(p (p) over bar) < 2.85 GeV/c(2)) = -0.409 +/- 0.033 (stat) +/- 0.006 (syst). In addition, the branching fraction of the decay B+ -> <(Lambda)over bar>(1520)p is measured to be B(B+ -> (Lambda) over bar (1520)p) = (3.15 +/- 0.48 (stat) +/- 0.07 (syst) +/- 0.26 (BF)) x 10(-7), where BF denotes the uncertainty on secondary branching fractions.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., Ruiz Valls, P., & Sanchez Mayordomo, C. (2016). Evidence for Exotic Hadron Contributions to Lambda(0)(b) -> J/psi p pi(-) Decays. Phys. Rev. Lett., 117(8), 082003–10pp.
Abstract: A full amplitude analysis of Lambda(0)(b) -> J/psi pi(-) decays is performed with a data sample acquired with the LHCb detector from 7 and 8 TeV pp collisions, corresponding to an integrated luminosity of 3 fb(-1). A significantly better description of the data is achieved when, in addition to the previously observed nucleon excitations N -> p pi(-), either the P-c(43800)(+) and P-c(4450)(+) -> J/psi p states, previously observed in Lambda(0)(b) -> J/psi pK(-) decays, or the Z(c)(4200)(-) -> J/psi pi(-) state, previously reported in B-0 -> J/psi K+pi(-) decays, or all three, are included in the amplitude models. The data support a model containing all three exotic states, with a significance of more than three standard deviations. Within uncertainties, the data are consistent with the P-c(4380)(+) and P-c(4 450)(+) production rates expected from their previous observation taking account of Cabibbo suppression.
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LHCb Collaboration(Aaij, R. et al), Jaimes Elles, S. J., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., et al. (2023). Evidence for Modification of b Quark Hadronization in High-Multiplicity pp Collisions at √s=13 TeV. Phys. Rev. Lett., 131(6), 061901–11pp.
Abstract: The production rate of B-s(0) mesons relative to B-0 mesons is measured by the LHCb experiment in pp collisions at a center-of-mass energy root s = 13 TeV over the forward rapidity interval 2 < y < 4.5 as a function of the charged particle multiplicity measured in the event. Evidence at the 3.4 sigma level is found for an increase of the ratio of B-s(0) to B-0 cross sections with multiplicity at transverse momenta below 6 GeV=c, with no significant multiplicity dependence at higher transverse momentum. Comparison with data from e(+)e(-) collisions implies that the density of the hadronic medium may affect the production rates of B mesons. This is qualitatively consistent with the emergence of quark coalescence as an additional hadronization mechanism in high-multiplicity collisions.
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