|
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). Test of Lepton Universality in b → sl+l- Decays. Phys. Rev. Lett., 131(5), 051803–13pp.
Abstract: The first simultaneous test of muon-electron universality using B+ -> K(+)l(+)l(-) and B-0 -> K*(0)l(+) l(-) decays is performed, in two ranges of the dilepton invariant-mass squared, q(2). The analysis uses beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb(-1). Each of the four lepton universality measurements reported is either the first in the given q(2) interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.
|
|
|
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). Search for the rare decays W+ → Ds+γ and Z → D0 γ at LHCb. Chin. Phys. C, 47(9), 093002–13pp.
Abstract: A search for the rare decays W+ -> D-s(+)gamma and Z -> D-0 gamma and is performed using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of 13TeV, corresponding to an integrated luminosity of 2.0fb(-1). No significant signal is observed for either decay mode and upper limits on their branching fractions are set using W+ -> mu(+)nu and Z ->mu(+)mu(-)decays as normalization channels. The upper limits are and at 95% confidence level for W+ -> D-s(+)gamma and Z -> D-0 gamma the and decay modes, respectively. This is the first reported search for Z -> D-0 gamma the decay, while the upper limit on the Z -> D-0 gamma branching fraction improves upon the previous best limit.
|
|
|
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). Amplitude analysis of B0 -> D0bar Ds+ pi- and B+ -> D- Ds+ pi+ decays. Phys. Rev. D, 108(1), 012017–30pp.
Abstract: Resonant contributions in B0 & RARR; over bar D0D+s & pi;- and B+ & RARR; D-D+s & pi;+ decays are determined with an amplitude analysis, which is performed both separately and simultaneously, where in the latter case isospin symmetry between the decays is assumed. The analysis is based on data collected by the LHCb detector in proton-proton collisions at center-of-mass energies of 7, 8, and 13 TeV. The full data sample corresponds to an integrated luminosity of 9 fb-1. A doubly charged spin-0 open-charm tetraquark candidate together with a neutral partner, both with masses near 2.9 GeV, are observed in the Ds & pi; decay channel.
|
|
|
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). First Observation of a Doubly Charged Tetraquark and Its Neutral Partner. Phys. Rev. Lett., 131(4), 041902–12pp.
Abstract: A combined amplitude analysis is performed for the decays B0-+ D0D thorn s & pi;- and B thorn -+ D-D thorn s & pi; thorn , which are related by isospin symmetry. The analysis is based on data collected by the LHCb detector in proton -proton collisions at center-of-mass energies of 7, 8, and 13 TeV. The full data sample corresponds to an integrated luminosity of 9 fb-1. Two new resonant states with masses of 2.908 ⠂ 0.011 ⠂ 0.020 GeV and widths of 0.136 ⠂ 0.023 ⠂ 0.013 GeV are observed, which decay to D thorn s & pi; thorn and D thorn s & pi;- respectively. The former state indicates the first observation of a doubly charged open-charm tetraquark state with minimal quark content 1/2cs over bar ud over bar ⠃, and the latter state is a neutral tetraquark composed of 1/2cs over bar u over bar d ⠃ quarks. Both states are found to have spin-parity of 0 thorn , and their resonant parameters are consistent with each other, which suggests that they belong to an isospin triplet.
|
|
|
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). J/ψ and D0 production in √s_NN=68.5 GeV PbNe collisions. Eur. Phys. J. C, 83(7), 658–11pp.
Abstract: The firstmeasurement of J/psi and D-0 production in PbNe collisions by the LHCb experiment in its fixed-target configuration is reported. The production of J/psi and D-0 mesons is studied with a beam of lead ions with an energy of 2.5 TeV per nucleon colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy of root s(NN) = 68.5 GeV. The J/psi/D-0 production crosssection ratio is studied as a function of rapidity, transverse momentum and collision centrality. These data are compared with measurements from pNe collisions at the same energy and showno difference in the observed J/psi suppression trend when comparing pNe and PbNe peripheral collisions with PbNe central collisions.
|
|