LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., et al. (2020). Observation of New Xi(0)(c) Baryons Decaying to Lambda K-+(c)-. Phys. Rev. Lett., 124(22), 222001–11pp.
Abstract: The Lambda K-+(c)- mass spectrum is studied with a data sample of pp collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 5.6 fb(-1) collected by the LHCb experiment. Three Xi(0)(c) states are observed with a large significance and their masses and natural widths are measured to be m[Xi(c)(2923)(0)] = 2923.04 +/- 0.25 +/- 0.20 +/- 0.14 MeV, Gamma[Xi(c)(2923)(0)] = 7.1 +/- 0.8 +/- 1.8 MeV, m[Xi(c)(2939)(0)] = 2938.55 +/- 0.21 +/- 0.17 +/- 0.14 MeV, Gamma[Xi(c)(2939)(0)] = 10.2 +/- 0.8 +/- 1.1 MeV, m[Xi(c)(2965)(0)] = 2964.88 +/- 0.26 +/- 0.14 +/- 0.14 MeV, Gamma[Xi(c)(2965)(0)] = 14.1 +/- 0.9 +/- 1.3 MeV, where the uncertainties are statistical, systematic, and due to the limited knowledge of the Lambda(+)(c) mass. The Xi(c)(2923)(0) and Xi(c)(2939)(0) baryons are new states. The Xi(c)(2965)(0) state is in the vicinity of the known Xi(c)(2970)(0) baryon; however, their masses and natural widths differ significantly.
|
Gisbert, H., & Ruiz Vidal, J. (2020). Improved bounds on heavy quark electric dipole moments. Phys. Rev. D, 101(11), 115010–5pp.
Abstract: New bounds on the electric dipole moment (EDM) of charm and bottom quarks are derived using the stringent limits on their chromo-EDMs. The new limits, vertical bar d(c)vertical bar < 1.5 x 10(-21) e cm and vertical bar d(b)vertical bar < 1.2 x 10(-20) e cm, improve the previous ones by about 3 orders of magnitude. These indirect bounds have implications for different models of new physics, including two-Higgs-doublet, leptoquarks, and supersymmetry models.
|
LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., et al. (2020). Measurement of CP-Averaged Observables in the B-0 -> K-star 0 mu(+)mu(-) Decay. Phys. Rev. Lett., 125(1), 011802–13pp.
Abstract: An angular analysis of the B-0 -> K-0 (-> K+pi(-))mu(+)mu(-) decay is presented using a dataset corresponding to an integrated luminosity of 4.7 fb(-1) of pp collision data collected with the LHCb experiment. The full set of CP-averaged observables are determined in bins of the invariant mass squared of the dimuon system. Contamination from decays with the K+ pi(-) system in an S-wave configuration is taken into account. The tension seen between the previous LHCb results and the standard model predictions persists with the new data. The precise value of the significance of this tension depends on the choice of theory nuisance parameters.
|
LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., et al. (2020). Measurement of the branching fraction of the decay B-s(0) -> (KSKS0)-K-0. Phys. Rev. D, 102(1), 012011–15pp.
Abstract: A measurement of the branching fraction of the decay B-s(0) -> (KSKS0)-K-0 is performed using proton- proton – collision data corresponding to an integrated luminosity of 5 fb(-1) collected by the LHCb experiment between 2011 and 2016. The branching fraction is determined to be B(B-s(0) -> (KSKS0)-K-0) = [8.3 +/- 1.6(stat) +/- 0.9(syst) +/- 0.8(norm) +/- 0.3(f(s)/f(d))] x 10(-6), where the first uncertainty is statistical, the second is systematic, and the third and fourth are due to uncertainties on the branching fraction of the normalization mode B-0 -> phi K(S)(0 )and the ratio of hadronization fractions f(s)/f(d). This is the most precise measurement of this branching fraction to date. Furthermore, a measurement of the branching fraction of the decay B-s(0) -> (KSKS0)-K-0 is performed relative to that of the B-s(0) -> (KSKS0)-K-0 channel, and is found to be B(B-s(0) -> (KSKS0)-K-0)/B(B-s(0) -> (KSKS0)-K-0) = [7.5 +/- 3.1(stat) 0.5(syst) +/- 0.3(f(s)/f(d))1 x 10(-2).
|
LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., et al. (2020). Search for CP violation and observation of P violation in Lambda(0)(b) -> p pi(-) pi(+) pi(-) decays. Phys. Rev. D, 102(5), 051101–12pp.
Abstract: A search for CP violation in the Lambda(0)(b) -> p pi(-) pi(+) pi(-) decay is performed using LHCb data corresponding to an integrated luminosity of 6.6 fb(-1) collected in pp collisions at center-of-mass energies of 7, 8 and 13 TeV. The analysis uses both triple product asymmetries and the unbinned energy test method. The highest significances of CP asymmetry are 2.9 standard deviations from triple product asymmetries and 3.0 standard deviations for the energy test method. Once the global p-value is considered, all results are consistent with no CP violation. Parity violation is observed at a significance of 5.5 standard deviations for the triple product asymmetry method and 5.3 standard deviations for the energy test method. The reported deviations are given in regions of phase space.
|
