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.
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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.
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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 observables in B+/- -> DK+/- and B+/- -> D pi+/- with D -> KS0 K+/- pi-/+ decays. J. High Energy Phys., 06(6), 058–25pp.
Abstract: Measurements of CP observables in B-+/- -> DK +/- and B-+/- -> D pi (+/-) decays are presented, where D represents a superposition of D-0 and D<overbar>0 states. The D meson is reconstructed in the three-body final states KS0K +/- pi -/+ and KS0K -/+ pi +/-. The analysis uses samples of B mesons produced in proton-proton collisions, corresponding to an integrated luminosity of 1.0, 2.0, and 6.0 fb(-1) collected with the LHCb detector at centre-of-mass energies of <mml:msqrt>s</mml:msqrt> = 7, 8, and 13 TeV, respectively. These measurements are the most precise to date, and provide important input for the determination of the CKM angle gamma.
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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 Lambda(0)(b) -> J/psi Lambda angular distribution and the Lambda(0)(b) polarisation in pp collisions. J. High Energy Phys., 06(6), 110–30pp.
Abstract: This paper presents an analysis of the Lambda(0)(b) -> J/psi Lambda angular distribution and the transverse production polarisation of Lambda(0)(b) baryons in proton-proton collisions at centre-of-mass energies of 7, 8 and 13TeV. The measurements are performed using data corresponding to an integrated luminosity of 4.9 fb(-1), collected with the LHCb experiment. The polarisation is determined in a fiducial region of Lambda(0)(b) transverse momentum and pseudorapidity of 1 < p(T) < 20 GeV/c and 2 < eta < 5, respectively. The data are consistent with Lambda(0)(b) baryons being produced unpolarised in this region. The parity-violating asymmetry parameter of the Lambda -> p pi(-) decay is also determined from the data and its value is found to be consistent with a recent measurement by the BES III collaboration.
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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.
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