Precision Measurement of the Mass and Lifetime of the Xi(0)(b) Baryon

Using a proton-proton collision data sample corresponding to an integrated luminosity of 3 fb(-1) collected by LHCb at center-of-mass energies of 7 and 8 TeV, about 3800 Xi(0)(b) -> Xi(+)(c)pi(-), Xi(+)(c) -> pK(-)pi(+) signal decays are reconstructed. From this sample, the first measurement of the Xi(0)(b) baryon lifetime is made, relative to that of the Lambda(0)(b) baryon. The mass differences M(Xi(0)(b)) - M(Lambda(0)(b)) and M(Xi(+)(c)) - M(Lambda(+)(c)) are also measured with precision more than 4 times better than the current world averages. The resulting values are tau(Xi b0)/tau(Lambda b0) = 1.006 +/- 0.018 +/- 0.010, M(Xi(0)(b)) - M(Lambda(0)(b)) = 172.44 +/- 0.39 +/- 0.17 MeV/c(2), M(Xi(+)(c)) - M(Lambda(+)(c)) = 181.51 +/- 0.14 +/- 0.10 MeV/c(2), where the first uncertainty is statistical and the second is systematic. The relative rate of Xi(0)(b) to Lambda(0)(b) baryon production is measured to be f(Xi b0) B(Xi(0)(b) -> Xi(+)(c)pi(-)) B(Xi(+)(c) -> pK(-)pi(+))/f(Lambda b0) B(Lambda(0)(b) -> Lambda(+)(c)pi(-)) B(Lambda(+)(c) -> pK(-)pi(+)) = (1.88 +/- 0.04 +/- 0.03) x 10(-2), where the first factor is the ratio of fragmentation fractions, b -> Xi(0)(b) relative to b -> Lambda(0)(b). Relative production rates as functions of transverse momentum and pseudorapidity are also presented.

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Concepts associés

Chargement

Publications associées

Chargement

Résumé

Official source

https://infoscience.epfl.ch/record/202523?ln=fr

À propos de ce résultat

Concepts associés (13)

Concepts associés

Chargement

Publications associées (116)

Chargement

Afficher plus

Publications associées

Chargement

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

Luminosité solaire

vignette|Evolution de la luminosité solaire au cours du temps. En astrophysique, la luminosité solaire, égale à celle du Soleil et notée L, est l'unité de luminosité conventionnellement utilisée pou

Radioactivité

vignette|Pictogramme signalant la présence de matière radioactive. (☢) vignette|La maison de Georges Cuvier, au Jardin des plantes de Paris, où Henri Becquerel découvrit la radioactivité en 1896. La

First Observation of the Doubly Charmed Baryon Decay Xi(++)(cc) -> Xi(+)(c)pi(+)

Liupan An, Guido Andreassi, Vladislav Balagura, Aurelio Bay, Violaine Bellée, Federico Betti, Marc-Olivier Bettler, Frédéric Blanc, Maxim Borisyak, Chunhui Chen, Peter Clarke, Victor Coco, Tommaso Colombo, Greig Alan Cowan, Adam Davis, Michel De Cian, Hans Dijkstra, Mirco Dorigo, Paolo Durante, Dipanwita Dutta, François Fleuret, Christoph Frei, Sebastiana Gianì, Olivier Göran Girard, Elena Graverini, Xiaoxue Han, Plamen Hristov Hopchev, Thibaud Humair, Axel Kuonen, Vladimir Macko, Pietro Marino, Maurizio Martinelli, Katharina Müller, Tatsuya Nakada, Tara Nanut, Matthew Needham, Niko Neufeld, Preema Rennee Pais, Luca Pescatore, Anton Petrov, Guillaume Max Pietrzyk, Cédric Potterat, Jessica Prisciandaro, Renato Quagliani, Gerhard Raven, Federico Leo Redi, Olivier Schneider, Maxime Schubiger, Evgenii Shmanin, Pavol Stefko, Maria Elena Stramaglia, Liang Sun, Frédéric Teubert, Mark Tobin, Minh Tâm Tran, Zheng Wang, Mingkui Wang, Yi Wang, Jian Wang, Jean Wicht, Zhirui Xu, Hang Yin, Lei Zhang, Yi Zhang, Yu Zheng

The doubly charmed baryon decay Xi(++)(cc) -> Xi(+)(c)pi(+) is observed for the first time, with a statistical significance of 5.9 sigma, confirming a recent observation of the baryon in the Lambda K-+(c)-pi(+)pi(+) final state. The data sample used corresponds to an integrated luminosity of 1.7 fb(-1), collected by the LHCb experiment in pp collisions at a center-of-mass energy of 13 TeV. The Xi(++)(cc) mass is measured to be 3620.6 +/- 1.5(stat) +/- 0.4(syst) +/- 0.3(Xi(+)(c)) MeV/c(2) and is consistent with the previous result. The ratio of branching fractions between the decay modes is measured to be [B(Xi(++)(cc) -> Xi(+)(c)pi(+)) x B(Xi(+)(c) -> pK(-)pi(+))]/[B(Xi(++)(cc) -> Lambda K-+(c)-pi(+)pi(+)) x B(Lambda(+)(c) -> pK(-)pi(+))] = 0.035 +/- 0.009 (stat) +/- 0.003 (syst).

AMER PHYSICAL SOC2018

Chargement

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

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

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.

Springer2014

Chargement

First Observation of a Baryonic B-c(+) Decay

Liupan An, Aurelio Bay, Marc-Olivier Bettler, Frédéric Blanc, Joël Bressieux, 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, Guido Haefeli, Xiaoxue Han, Pierre Jaton, Chitsanu Khurewathanakul, Ilya Komarov, Yiming Li, Pietro Marino, Maurizio Martinelli, Bastien Luca Muster, Tatsuya Nakada, Matthew Needham, Niko Neufeld, Luca Pescatore, Cédric Potterat, Jessica Prisciandaro, Barinjaka Rakotomiaramanana, Gerhard Raven, Julien Rouvinet, Olivier Schneider, Liang Sun, Frédéric Teubert, Mark Tobin, Minh Tâm Tran, Maria Vieites Diaz, Jian Wang, Jean Wicht, Songmei Wu, Zhirui Xu, Lei Zhang, Yi Zhang

A baryonic decay of the B-c(+) meson, B-c(+) -> J/psi p (p) over bar pi(+) is observed for the first time, with a significance of 7.3 standard deviations, in pp collision data collected with the LHCb detector and corresponding to an integrated luminosity of 3.0 fb(-1) taken at center-of-mass energies of 7 and 8 TeV. With the B-c(+) -> J/psi pi(+) decay as the normalization channel, the ratio of branching fractions is measured to be B(B-c(+) -> J/psi p (p) over bar pi(+)) /B(B-c(+) -> J/psi pi(+)) = 0.143(-0.034)(+0.039) (stat) +/- 0.013 (syst). The mass of the B-c(+) messon is determined as M(B-c(+)) = 6274.0 +/- 0.4 (sysst) MeV/c(2), using the B-c(+) -> J/psi p (p) over bar pi(+) channel.

Amer Physical Soc2014

Chargement

Afficher plus