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LHCb Collaboration(Aaij, R. et al), Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2021). Angular analysis of B0 -> D*- D*s+ with D*s+ -> Ds + gamma decays. J. High Energy Phys., 06(6), 177–30pp.
Abstract: The first full angular analysis of the B0 -> D-Ds+ decay is performed using 6 fb(-1) of pp collision data collected with the LHCb experiment at a centre-of-mass energy of 13 TeV. The Ds+-> Ds+gamma and D*- -> D<overbar></mml:mover>0- vector meson decays are used with the subsequent Ds+ -> K+K-pi (+) and D<overbar></mml:mover>0 -> K+pi (-) decays. All helicity amplitudes and phases are measured, and the longitudinal polarisation fraction is determined to be f(L) = 0.578 +/- 0.010 +/- 0.011 with world-best precision, where the first uncertainty is statistical and the second is systematic. The pattern of helicity amplitude magnitudes is found to align with expectations from quark-helicity conservation in B decays. The ratio of branching fractions [B(B0 -> D-Ds+) x B(Ds+-> Ds+gamma)]/B(B-0 -> D(*-)Ds+) is measured to be 2.045 +/- 0.022 +/- 0.071 with world-best precision. In addition, the first observation of the Cabibbo-suppressed B-s -> D(*-)Ds+ decay is made with a significance of seven standard deviations. The branching fraction ratio B(B-s -> D(*-)Ds<mml:mo>+)/B(B-0 -> D(*-)Ds<mml:mo>+) is measured to be 0.049 +/- 0.006 +/- 0.003 +/- 0.002, where the third uncertainty is due to limited knowledge of the ratio of fragmentation fractions.<fig id=“Figa” position=“anchor”><graphic position=“anchor” specific-use=“HTML” mime-subtype=“JPEG” xmlns:xlink=“http://www.w3.org/1999/xlink” xlink:href=“MediaObjects/13130202116089FigaHTML.jpg” id=“MO1”></graphic
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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.
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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 the B0s → D*+ D*- decay. J. High Energy Phys., 07(7), 119–19pp.
Abstract: The first observation of the B-s(0) -> D*+ D*- decay and the measurement of its branching ratio relative to the B-0 -> D*+ D*(-) decay are presented. The data sample used corresponds to an integrated luminosity of 9 fb(-1) of proton-proton collisions recorded by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV between 2011 and 2018. The decay is observed with more than 10 standard deviations and the time-integrated ratio of branching fractions is determined to be [GRAPHICS] . where the first uncertainty is statistical, the second systematic and the third due to the uncertainty of the fragmentation fraction ratio f(s)/f(d). The B-s(0) -> D*(+) D*(-) branching fraction is calculated to be [GRAPHICS] . where the fourth uncertainty is due to the B-0 -> D*(+) D*(-) branching fraction. These results are calculated using the average B-s(0) meson lifetime in simulation. Correction factors are reported for scenarios where either a purely heavy or a purely light B-s(0) eigenstate is considered.
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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 ratio of branching fractions B(B+c → B0sπ+)/B(B+c → J/ψπ+). J. High Energy Phys., 07(7), 066–19pp.
Abstract: The ratio of branching fractions of B-c(+) -> B-s(0)pi(+) and B-c(+) -> J/psi pi(+) decays is measured with proton-proton collision data of a centre-of-mass energy of 13TeV. The data were collected with the LHCb experiment during 2016-2018, corresponding to an integrated luminosity of 5.4 fb(-1). The B-s(0) mesons are reconstructed via the decays B-s(0) -> J/psi phi and B-s(0) -> D-s(-)pi(+). The ratio of branching fractions is measured to be B(B-c(+) -> B-s(0)pi(+))/B(B-c(+) -> J/psi pi(+)) = 91 +/- 10 +/- 8 +/- 3 where the first uncertainty is statistical, the second is systematic and the third is due to the knowledge of the branching fractions of the intermediate state decays.
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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 and branching fraction measurement of the Λb0 → Ds- p decay. J. High Energy Phys., 07(7), 075–23pp.
Abstract: The first observation of the Lambda(0)(b) -> D-s(-) p decay is presented using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of root s = 13TeV, corresponding to a total integrated luminosity of 6 fb(-1). Using the Lambda(0)(b) -> Lambda(+pi-)(c) decay as the normalisation mode, the branching fraction of the Lambda(0)(b) -> D-s(-) p decay is measured to be B (Lambda(0)(b) -> D-s(-) p) = (12.6 +/- 0.5 +/- 0.3 +/- 1.2) x 10(-6), where the first uncertainty is statistical, the second systematic and the third due to uncertainties in the branching fractions of the Lambda(0)(b) -> Lambda(+pi-)(c), D-s(-) -> K-K+pi(-) and Lambda(+)(c) -> pK(-)pi(+) decays.
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