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LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., & Ruiz Vidal, J. (2021). Updated search for B-c(+) decays to two charm mesons. J. High Energy Phys., 12(12), 117–23pp.
Abstract: A data set corresponding to an integrated luminosity of 9 fb(-1) of proton-proton collisions collected by the LHCb experiment has been analysed to search for D-(s)(()*())+ ((D) over bar)(*)0 decays. The decays are fully or partially reconstructed, where one or two (8) missing neutral pions or photons from the decay of an excited charm meson are allowed. Upper limits for the branching fractions, normalised to B+ decays to final states with similar topologies, are obtained for sixteen B-c(+) decay modes. For the decay B-c(+) -> D-s(+)(D) over bar (0), an excess with a significance of 3.4 standard deviations is found.
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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). Precision measurement of the B-c(+) meson mass. J. High Energy Phys., 07(7), 123–21pp.
Abstract: A precision measurement of the B-c(+) meson mass is performed using proton- proton collision data collected with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to a total integrated luminosity of 9.0 fb(-1). The B-c(+) mesons are reconstructed via the decays B-c(+)-> J/psi pi(+), B-c(+)-> J/psi pi(+)pi(-)pi(+), B-c(+)-> J/psi pp<overbar>pi(+), B-c(+)-> J/psi D-s(+), B-c(+)-> J/psi (DK+)-K-0 and B-c(+)-> B-s(0)pi(+). Combining the results of the individual decay channels, the B-c(+) mass is measured to be 6274.47 +/- 0.27 (stat) +/- 0.17 (syst) MeV/c(2). This is the most precise measurement of the B-c(+) mass to date. The difference between the B-c(+) and B-s(0) meson masses is measured to be 907.75 +/- 0.37 (stat) +/- 0.27 (syst) MeV/c(2).
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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). Study of the psi(2)(3823) and chi(c1)(3872) states in B+->(J/psi pi(+)pi(-))K(+)decays. J. High Energy Phys., 08(8), 123–29pp.
Abstract: The decays B+-> J/psi pi(+)pi(-)K(+)are studied using a data set corresponding to an integrated luminosity of 9 fb(-1)collected with the LHCb detector in proton-proton collisions between 2011 and 2018. Precise measurements of the ratios of branching fractions with the intermediate psi(2)(3823), chi(c1)(3872) and psi(2S) states are reported. The values areBB+->psi 2(“>3823K+xB psi 2(”>3823 -> J/psi pi+pi-BB+->chi c1>3872K+xB chi c1>3872 -> J/psi pi+pi-=>3.56 +/- 0.67 +/- 0.11x10-2,BB+->psi 2>3823K+xB psi 2>3823 -> J/psi pi+pi-BB+->psi>2SK+xB psi>2S -> J/psi pi+pi-=>1.31 +/- 0.25 +/- 0.04x10-3,BB+->chi c1>3872K+xB chi c1>3872 -> J/psi pi+pi-BB+->psi>2SK+xB psi>2S -> J/psi pi+pi-= where the first uncertainty is statistical and the second is systematic. The decay of B+->psi(2)(3823)K(+)with psi(2)(3823)-> J/psi pi(+)pi(-)is observed for the first time with a significance of 5.1 standard deviations. The mass differences between the psi(2)(3823), chi(c1)(3872) and psi(2S) states are measured to be m chi c1>3872-m psi 2>3823=47. 50 +/- 0.53 +/- 0.13MeV/c2,m psi 2 2S=185.49 +/- 0.06 +/- 0.03MeV/c2, resulting in the most precise determination of the chi(c1)(3872) mass. The width of the psi(2)(3823) state is found to be below 5.2 MeV at 90% confidence level. The Breit-Wigner width of the chi(c1)(3872) state is measured to be Gamma chi c13872BW=0.96-0.18+0.19 +/- 0.21MeV={0.96}_{-0.18}<^>{+0.19}\pm 0.21\;\mathrm{MeV} which is inconsistent with zero by 5.5 standard deviations.
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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). Search for the doubly heavy Xi bc0 baryon via decays to D(0)pK(-). J. High Energy Phys., 11(11), 095–21pp.
Abstract: A search for the doubly heavy Xi bc0 baryon using its decay to the D(0)pK(-) final state is performed using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the LHCb experiment between 2016 and 2018, corresponding to an integrated luminosity of 5.4 fb(-1). No significant signal is found in the invariant mass range from 6.7 to 7.2 GeV/c(2). Upper limits are set at 95% credibility level on the ratio of the Xi bc0 production cross-section times its branching fraction to D(0)pK(-) relative to that of the Lambda b0 -> D0pK- decay. The limits are set as a function of the Xi bc0 mass and lifetime hypotheses, in the rapidity range from 2.0 to 4.5 and in the transverse momentum region from 5 to 25 GeV/c. Upper limits range from 1.7 x 10(-2) to 3.0 x 10(-1) for the considered Xi bc0 mass and lifetime hypotheses.
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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. (2019). Measurement of the ratio of branching fractions of the decays0(2S) and arrange Lambda. J. High Energy Phys., 03(3), 126–16pp.
Abstract: Using pp collisions corresponding to 3 fb integrated luminosity, recorded by the LHCb experiment at centre- of- mass energies of 7 and 8 TeV, the ratio of branching fractions B (0b ! (2 S) ) =B (0b ! J= ) = 0 : 513 0 : 023 (stat) 0 : 016 (syst) 0 : 011 (B) is determined. The first uncertainty is statistical, the second is systematic and the third is due to the external branching fractions used.
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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. (2019). Amplitude analysis of B-s(0) -> K-S(0) K-+/-pi(-/+) decays. J. High Energy Phys., 06(6), 114–28pp.
Abstract: The first untagged decay-time-integrated amplitude analysis of B 0 s ! K 0 S K decays is performed using a sample corresponding to 3: 0 fb of pp collision data recorded with the LHCb detector during 2011 and 2012. The data are described with an amplitude model that contains contributions from the intermediate resonances K 9892) 0;+, K 2 91430) 0;+ and K 0 91430) 0;+, and their charge conjugates. Measurements of the branching fractions of the decay modes B 0 s ! K 9892) K and B 0 s ! K 9892) 0 K 0 are in agreement with, and more precise than, previous results. The decays B 0 s ! K 0 91430) K and B 0 s ! K 0 91430) 0 K 0 are observed for the fi rst time, each with signi fi cance over 10 standard deviations.
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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. (2019). Measurement of CP observables in the process B-0 -> DK*0 with two- and four-body D decays. J. High Energy Phys., 08(8), 041–30pp.
Abstract: Measurements of CP observables in B-0 -> DK0 decays are presented, where D represents a superposition of D-0 and D0 states. The D meson is reconstructed in the two-body final states K+pi(-), pi K-+(-), K+K- and pi(+)pi(-), and, for the first time, in the fourbody final states K+pi(-)pi(+)pi(-), pi K-+(-)pi(+)pi(-) and pi(+)pi(-)pi(+)pi(-). The analysis uses a sample of neutral B mesons produced in proton-proton collisions, corresponding to an integrated luminosity of 1.0, 2.0 and 1.8 fb(-1) collected with the LHCb detector at centre-of-mass energies of ,8 and 13 TeV, respectively. First observations of the decays B-0 -> D(pi K-+(-))K-0 and B-0 -> D(pi(+)pi(-)pi(+)pi(-))K-0 are obtained. The measured observables are interpreted in terms of the CP -violating weak phase 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. (2019). Observation of the Lambda(0)(b) -> chi(c1) (3872)pK(-) decay. J. High Energy Phys., 09(9), 028–20pp.
Abstract: Using proton-proton collision data, collected with the LHCb detector and corresponding to 1.0, 2.0 and 1.9 fb(-1) of integrated luminosity at the centre-of-mass energies of 7, 8, and 13 TeV, respectively, the decay Lambda(0)(b) -> chi(c1)(3872)pK(-) with chi(c1)(3872) -> J/psi pi(+)pi(-) is observed for the first time. The significance of the observed signal is in excess of seven standard deviations. It is found that (58 +/- 15)% of the decays proceed via the two-body intermediate state chi(c1)(3872)Lambda(1520). The branching fraction with respect to that of the Lambda(0)(b) -> psi(2S)pK(-) decay mode, where the psi(2S) meson is reconstructed in the J/psi pi(+)pi(-) final state, is measured to be: B(Lambda(0)(b) -> chi(c1)(3872)pK(-))/B (Lambda(0)(b) -> psi(2S)pK(-)) x B(chi(c1)(3872) -> J/psi pi(+)pi(-))/B(psi(2S) -> J/psi pi(+)pi(-)) = (5.4 +/- 1.1 +/- 0.2) x 10(-2), where the first uncertainty is statistical and the second is systematic.
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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. (2019). Study of the B-0 (770)degrees K-*(892)(0) decay with an amplitude analysis of B-0 ((+-))(K+pi(-)) decays. J. High Energy Phys., 05(5), 026–31pp.
Abstract: An amplitude analysis of B-0 ((+-))(K+-) decays is performed in the two-body invariant mass regions 300 < m((+-)) < 1100 MeV/c(2), accounting for the (0), , f(0)(500), f(0)(980) and f(0)(1370) resonances, and 750 < m(K+-) < 1200 MeV/c(2), which is dominated by the K-*(892)(0) meson. The analysis uses 3 fb(-1) of proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The CP averages and asymmetries are measured for the magnitudes and phase differences of the con- tributing amplitudes. The CP-averaged longitudinal polarisation fractions of the vector-vector modes are found to be fK*0 = 0.164 +/- 0.015 +/- 0.022 and fK*0 = 0.68 +/- 0.17 +/- 0.16, and their CP asymmetries, AK*0 = -0.62 +/- 0.09 +/- 0.09 and AK*0 = -0.13 +/- 0.27 +/- 0.13, where the first uncertainty is statistical and the second systematic.
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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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