Measurements of the B+, B-0, B-s(0) meson and Lambda(0)(b) baryon lifetimes

Measurements of b-hadron lifetimes are reported using p p collision data, corresponding to an integrated luminosity of 1.0 fb(-1), collected by the LHCb detector at a centre-of-mass energy of 7 TeV. Using the exclusive decays B+ -> J/psi K+, B-0 -> J/psi K* (892)(0), B-0 -> J/K-s(0), Lambda(0)(b) -> J/psi Lambda and B-s(0) -> J/psi phi the average decay times in these modes are measured to be tau(B+) -> J/psi K+ = 1.637 +/- 0.004 +/- 0.003 p s, tau(B0) -> J/psi K*(0) = 1.524 +/- 0.006 +/- 0.004 p s, tau(0)(B) -> J/psi K-s(0) = 1.499 +/- 0.013 +/- 0.005 ps, tau Lambda(0)(b) -> J/psi Lambda = 1.415 +/- 0.027 +/- 0.006 ps, tau(0)(Bs) -> J/psi phi = 1.480 +/- 0.011 +/- 0.005 ps, where the first uncertainty is statistical and the second is systematic. These represent the most precise lifetime measurements in these decay modes. In addition, ratios of these lifetimes, and the ratio of the decay-width difference, Delta Gamma(d), to the average width, Gamma(d), in the B-0 system, Delta Gamma(d)/Gamma(d) = -0.044 +/- 0.025 +/- 0.011, are reported. All quantities are found to be consistent with Standard Model expectations.

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Vladislav Balagura, Aurelio Bay, Marc-Olivier Bettler, Frédéric Blanc, Joël Bressieux, Daniel Hugo Cámpora Pérez, Lucía Castillo García, Peter Clarke, Victor Coco, Greig Alan Cowan, Adam Davis, Michel De Cian, Hans Dijkstra, Mirco Dorigo, Frédéric Guillaume Dupertuis, Paolo Durante, Christoph Frei, Luis Alberto Granado Cardoso, Guido Haefeli, Pierre Jaton, Chitsanu Khurewathanakul, Ilya Komarov, Yiming Li, Johan Luisier, Pietro Marino, Maurizio Martinelli, Raluca Anca Muresan, Bastien Luca Muster, Tatsuya Nakada, Matthew Needham, Niko Neufeld, Luca Pescatore, Cédric Potterat, Jessica Prisciandaro, Albert Puig Navarro, Barinjaka Rakotomiaramanana, Gerhard Raven, Julien Rouvinet, Olivier Schneider, Liang Sun, Frédéric Teubert, Mark Tobin, Minh Tâm Tran, Jian Wang, Jean Wicht, Songmei Wu, Yi Zhang, Lei Zhang
Springer, 2014
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https://infoscience.epfl.ch/record/199032?ln=fr

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Luminosité

En astronomie, la luminosité est la quantité totale d'énergie émise par unité de temps (le flux énergétique), par une étoile, une galaxie, ou n'importe quel autre objet céleste. Elle s'exprime en pr

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Luminosité solaire

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Measurement of the CKM angle gamma from a combination of B-+/- -> Dh(+/-) analyses

Vladislav Balagura, Aurelio Bay, Marc-Olivier Bettler, Frédéric Blanc, Joël Bressieux, Peter Clarke, Victor Coco, Greig Alan Cowan, Adam Davis, Michel De Cian, Hans Dijkstra, Frédéric Guillaume Dupertuis, Vincent Fave, Christoph Frei, Guido Haefeli, Plamen Hristov Hopchev, Pierre Jaton, Anne Keune, Ilya Komarov, Yiming Li, Johan Luisier, Maurizio Martinelli, Raluca Anca Muresan, Bastien Luca Muster, Tatsuya Nakada, Matthew Needham, Niko Neufeld, Cédric Potterat, Jessica Prisciandaro, Barinjaka Rakotomiaramanana, Gerhard Raven, Julien Rouvinet, Christophe Salzmann, Olivier Schneider, Liang Sun, Frédéric Teubert, Mark Tobin, Minh Tâm Tran, Jian Wang, Jean Wicht, Songmei Wu, Yi Zhang, Lei Zhang

A combination of three LHCb measurements of the CKM angle gamma is presented. The decays B-+/- -> DK +/- and B-+/- -> D pi(+/-) are used, where D denotes an admixture of D-0 and (D) over bar (0) mesons, decaying into K+K-, pi(+)pi(-), K-+/-pi(-/+), K-+/-pi(-/+)pi(+/-)pi(-/+), or K-S(0)pi(+)pi(-) final states. All measurements use a dataset corresponding to 1.0 fb-1 of integrated luminosity. Combining results from B-+/- -> DK +/- Dill decays alone a best-fit value of gamma = 72.0 degrees is found, and confidence intervals are set gamma is an element of [56.4, 86.7]degrees at 68% CL, gamma is an element of [42.6, 99.6]degrees at 95% CL. The best-fit value of gamma found from a combination of results from B-+/- -> D pi(+/-) decays alone, is gamma = 18.9 degrees, and the confidence intervals gamma is an element of [7.4, 99.2]degrees boolean OR [167.9, 176.4]degrees at 68% CL are set, without constraint at 95% CL The combination of results from B1 DKI and B -> DTC decays gives a best-fit value of y = 72.6 degrees and the confidence intervals gamma is an element of [55.4, 82.3]degrees at 68% CL, gamma is an element of [40.2, 92.7]degrees at 95% CL are set. All values are expressed modulo 180 degrees, and are obtained taking into account the effect of D-0-(D) over bar (0) mixing. (C) 2013 CERN. Published by Elsevier B.V. All rights reserved.

Elsevier Science Bv2013

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Measurement of the lifetime of the B-c(+) meson using the B-c(+) -> J/psi pi(+) decay mode

Liupan An, Aurelio Bay, Marc-Olivier Bettler, Frédéric Blanc, Peter Clarke, Victor Coco, Greig Alan Cowan, Adam Davis, Michel De Cian, Hans Dijkstra, Mirco Dorigo, Frédéric Guillaume Dupertuis, Paolo Durante, Christoph Frei, Sebastiana Gianì, Elena Graverini, Guido Haefeli, Xiaoxue Han, Pierre Jaton, Chitsanu Khurewathanakul, Ilya Komarov, Yiming Li, Alessandro Mapelli, Pietro Marino, Maurizio Martinelli, Bastien Luca Muster, Tatsuya Nakada, Matthew Needham, Niko Neufeld, Luca Pescatore, Cédric Potterat, Jessica Prisciandaro, Barinjaka Rakotomiaramanana, Gerhard Raven, Federico Leo Redi, Julien Rouvinet, Olivier Schneider, Liang Sun, Frédéric Teubert, Mark Tobin, Minh Tâm Tran, Maria Vieites Diaz, Jian Wang, Zhirui Xu, Yi Zhang, Lei Zhang

The difference in total widths between the B-c(+) and B+ mesons is measured using a data sample corresponding to an integrated luminosity of 3.0 fb(-1) collected by the LHCb experiment in 7 and 8 TeV centre-of-mass energy proton-proton collisions at the LHC. Through the study of the time evolution of B-c(+) -> J/psi pi(+) and B+ -> J/psi K+ decays, the width difference is measured to be Delta Gamma = Gamma(Bc+) - Gamma(Bc+) = 4.46 +/- 0.14 +/- 0.07 mm(-1) c, where the first uncertainty is statistical and the second systematic. The known lifetime of the B+ meson is used to convert this to a precise measurement of the B-c(+) clifetime, tau(Bc+) = 513.4 +/- 11.0 +/- 5.7 fs, where the first uncertainty is statistical and the second is systematic. (C) 2015 The Authors. Published by Elsevier B.V.

Elsevier Science Bv2015

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Precision Measurement of CP Violation in B-S(0) -> J/Psi K+K- Decays

The time-dependent CP asymmetry in B-S(0) -> J/Psi K+K- decays is measured using pp collision data, corresponding to an integrated luminosity of 3.0 fb(-1), collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. In a sample of 96 000 B-S(0) -> J/Psi K+K- decays, the CP-violating phase phi(s) is measured, as well as the decay widths GL and GH of the light and heavy mass eigenstates of the B-s(0)-(B) over bar (0)(s) system. The values obtained are phi(s) = -0.058 +/- 0.049 +/- 0.006 rad, Gamma(s) equivalent to (Gamma(L) + Gamma(H))/2 = 0.6603 +/- 0.0027 +/- 0.0015 ps(-1), and Delta Gamma(s) equivalent to Gamma(L)-Gamma(H) = 0.0805 +/- 0.0091 +/- 0.0032 ps(-1), where the first uncertainty is statistical and the second, systematic. These are the most precise single measurements of those quantities to date. A combined analysis with B-s(0) -> J/Psi pi(+)pi(-) decays gives phi(s) = -0.010 +/- 0.039 rad. All measurements are in agreement with the standard model predictions. For the first time, the phase phi(s) is measured independently for each polarization state of the K+K- system and shows no evidence for polarization dependence.

Amer Physical Soc2015

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