|
LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., Remon Alepuz, C., et al. (2023). Search for the rare hadronic decay Bs0 → p(p)over-bar. Phys. Rev. D, 108(1), 012007–12pp.
Abstract: A search for the rare hadronic decay B-s(0) -> p (p) over bar is performed using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb(-1). No evidence of the decay is found and an upper limit on its branching fraction is set at B(B-s(0) -> p (p) over bar) < 4.4(5.1)x 10(-9) at 90% (95%) confidence level; this is currently the world's best upper limit. The decay mode B-0 -> p<(p)over bar> is measured with very large significance, confirming the first observation by the LHCb experiment in 2017. The branching fraction is determined to be B(B-0 -> p (p) over bar) = (1.27 +/- 0.15 +/- 0.05 +/- 0.04) 10(-8), where the first uncertainty is statistical, the second is systematic and the third is due to the external branching fraction of the normalization channel B-0 -> K+pi(-). The combination of the two LHCb measurements of the B-0 -> p (p) over bar branching fraction yields B(B-0 -> p (p) over bar) (1.27 +/- 0.13 +/- 0.05 +/- 0.03) x 10(-8).
|
|
|
LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., & Ruiz Vidal, J. (2023). Direct CP violation in charmless three-body decays of B± mesons. Phys. Rev. D, 108(1), 012008–17pp.
Abstract: Measurements of CP asymmetries in charmless three-body decays of B-+/- mesons are reported using proton-proton collision data collected by the LHCb detector, corresponding to an integrated luminosity of 5.9 fb(-1). The previously observed CP asymmetry in B-+/- -> pi(K+K-)-K-+/- decays is confirmed, and CP asymmetries are observed with a significance of more than five standard deviations in the B-+/- -> pi(+/-)pi(+)pi and B-+/- -> (KK+K-)-K-+/- decays, while the CP asymmetry of B-+/- -> K-+/-pi(+)pi(-) decays is confirmed to be compatible with zero. The distributions of these asymmetries are also studied as a function of the three-body phase space and suggest contributions from rescattering and resonance interference processes. An indication of the presence of the decays B+ -> pi(+) chi(c0) (1P) in both B+ ->pi(+)pi(+)pi and B+ ->pi+K+K- decays is observed, as is CP violation involving these amplitudes.
|
|
|
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). Measurement of the mass difference and relative production rate of the Ωb- and Ξb- baryons. Phys. Rev. D, 108(5), 052008–16pp.
Abstract: The mass difference between the Omega -b and Xi -b baryons is measured using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb-1, and is found to be mo Omega -bthorn – mo Xi -bthorn 1/4 248.54? 0.51ostatthorn ? 0.38osystthorn MeV=c2. The mass of the Omega -b baryon is measured to be mo Omega -bthorn 1/4 6045.9 ? 0.5ostatthorn ? 0.6osystthorn MeV=c2. This is the most precise determination of the Omega -b mass to date. In addition, the production rate of Omega -b baryons relative to that of Xi -b baryons is measured for the first time in pp collisions, using an LHCb dataset collected at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 6 fb-1. Reconstructing beauty baryons in the kinematic region 2 < <eta> < 6 and pT < 20 GeV=c with their decays to a J=psi meson and a hyperon, the ratio f Omega- b f Xi- b tation fractions of b quarks into Omega -b and Xi -b baryons, respectively, and B represents the branching fractions of their respective decays. Bo Omega- b -> J=psi Omega -thorn x Bo Xi- b -> J=psi Xi -thorn 1/4 0.120 ? 0.008ostatthorn ? 0.008osystthorn, is obtained, where f Omega- b and f Xi -b are the fragmen-
|
|
|
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). Measurement of the Prompt D0 Nuclear Modification Factor in p-Pb Collisions at √SNN=8.16 TeV. Phys. Rev. Lett., 131(10), 102301–12pp.
Abstract: The production of prompt D0 mesons in proton-lead collisions in both the forward and backward rapidity regions at a center-of-mass energy per nucleon pair of √SNN= = 8.16 TeV is measured by the sNN LHCb experiment. The nuclear modification factor of prompt D0 mesons is determined as a function of the transverse momentum pT, and the rapidity in the nucleon-nucleon center-of-mass frame y*. In the forward rapidity region, significantly suppressed production with respect to pp collisions is measured, which provides significant constraints on models of nuclear parton distributions and hadron production down to the very low Bjorken-x region of similar to 10-5. In the backward rapidity region, a suppression with a significance of 2.0-3.8 standard deviations compared to parton distribution functions in a nuclear environment expectations is found in the kinematic region of pT 6 GeV/c and -3.25 < y* < -2.5, corresponding to x similar to 0.01.
|
|
|
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). Observation and branching fraction measurement of the decay Ξb- → Λ0 bπ-. Phys. Rev. D, 108(7), 072002–16pp.
Abstract: The decay E-b -> A0bx-- is observed using a proton-proton collision data sample collected at center-of-ffiffimass energy p s 1/4 13 TeV with the LHCb detector, corresponding to an integrated luminosity of 5.5 fb-1. This process is mediated by the s -> uu over bar d quark-level transition, where the b quark in the E-b baryon is a spectator in the decay. Averaging the results obtained using the two A0b decay modes, A0b -> A thorn c x-- and A0b -> A thorn c x--x- thorn x--, the relative production ratio is measured to be ofE-b =fA0b thorn BoE-b -> A0bx-- thorn 1/4 o7.3 ⠂ 0.8 ⠂ 0.6 thorn x 10-4. Here the uncertainties are statistical and systematic, respectively, and fE-bofA0b thorn is the fragmentation fraction for a b quark into a E-b (A0b) baryon. Using an independent measurement of fE-b =fA0b, the branching fraction BoE-b -> A0bx-- thorn 1/4 o0.89 ⠂ 0.10 ⠂ 0.07 ⠂ 0.29 thorn % is obtained, where the last uncertainty is due to the assumed SU(3) flavor symmetry in the determination of fE-b =fA0b.
|
|
|
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). Precision Measurement of CP Violation in the Penguin-Mediated Decay B0s → φφ. Phys. Rev. Lett., 131(17), 171802–12pp.
Abstract: A flavor-tagged time-dependent angular analysis of the decay B0s -> phi phi is performed using pp collision integrated luminosity of 6 fb-1. The CP-violating phase and direct CP-violation parameter are measured to s = -0.042 +/- 0.075 +/- 0.009 rad and l lambda l = 1.004 +/- 0.030 +/- 0.009, respectively, assuming the same values for all polarization states of the phi phi system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using pp collisions at center-of-mass energies of 7 and 8 TeV, yielding phi sss over bar s = -0.074 +/- 0.069 rad and l lambda l = 1.009 +/- 0.030. This is the most precise study of time-dependent CP violation in a penguindominated B meson decay. The results are consistent with CP symmetry and with the standard model predictions.
|
|
|
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). Observation of New Baryons in the Ξb- π+π- and Ξb0π+π- Systems. Phys. Rev. Lett., 131(17), 171901–11pp.
Abstract: The first observation and study of two new baryonic structures in the final state Xi(0)(b)pi(+)pi(-) and the confirmation of the Xi(b)(6100)(-) state in the Xi(-)(b)pi(+)pi(-) decay mode are reported using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb(-1). In addition, the properties of the known Xi(b)*(0), Xi(b)'(-) and Xi(b)*(-) resonances are measured with improved precision. The new decay mode of the Xi(0)(b) baryon to the Xi(+)(c) pi(-) pi(+) pi(-) final state is observed and exploited for the first time in these measurements.
|
|
|
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). Observation of a J/ψΛ Resonance Consistent with a Strange Pentaquark Candidate in B- → J/ψΛ(p)over-bar Decays. Phys. Rev. Lett., 131(3), 031901–11pp.
Abstract: An amplitude analysis of B- -> J/psi Lambda(p) over bar decays is performed using 4400 signal candidates selected on a data sample of pp collisions recorded at center-of-mass energies of 7, 8, and 13 TeV with the LHCb detector, corresponding to an integrated luminosity of 9 fb(-1). A narrow resonance in the J/psi Lambda system, consistent with a pentaquark candidate with strangeness, is observed with high significance. The mass and the width of this new state are measured to be 4338.2 +/- 0.7 +/- 0.4 MeV and 7.0 +/- 1.2 +/- 1.3 MeV, where the first uncertainty is statistical and the second systematic. The spin is determined to be 1/2 and negative parity is preferred. Because of the small Q-value of the reaction, the most precise single measurement of the B- mass to date, 5279.44 +/- 0.05 +/- 0.07 MeV, is obtained.
|
|
|
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). Measurement of the Ratios of Branching Fractions R(D*) and R(D0). Phys. Rev. Lett., 131(11), 111802–13pp.
Abstract: The ratios of branching fractions R(D*) = B((B) over bar -> D* tau(-) (v) over bar (tau))/B((B) over bar -> D*.mu(-)(v) over bar mu) and R(D-0) = B(B- -> D(0)t-mu(-)(v) over bar mu) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb(-1) of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode tau(-) -> mu(-)v(tau)(v) over bar mu. The measured values are R(D) = 0.281 +/- 0.018 +/- 0.024 and R(D-0) = 0.441 +/- 0.060 +/- 0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is rho = -0.43. The results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in 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). Evidence of a J / ψK0S Structure in B0 → J / ψφK0S Decays. Phys. Rev. Lett., 131(13), 131901–11pp.
Abstract: An amplitude analysis of B0 -> J=psi phi K0S decays is performed using proton-proton collision data, corresponding to an integrated luminosity of 9 fb-1, collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. Evidence with a significance of 4.0 standard deviations of a structure in the J=psi K0S system, named T theta psi s1o4000 thorn 0, is seen, with its mass and width measured to be 3991 thorn 12 thorn 9 -10 -17 MeV=c2 and 105 thorn 29 thorn 17 -25 -23 MeV, respectively, where the first uncertainty is statistical and the second systematic. The T theta psi s1 o4000 thorn 0 state is likely to be the isospin partner of the T theta psi s1 o4000 thorn thorn state, previously observed in the J=psi K thorn system of the B thorn -> J=psi phi K thorn decay. When isospin symmetry for the charged and neutral T theta psi s1 o4000 thorn states is assumed, the signal significance increases to 5.4 standard deviations.
|
|