Measurement of the parity-violating asymmetry parameter alpha_b and the helicity amplitudes for the decay Lambda_b->J/psi+Lambda with the ATLAS detector

A measurement of the parity-violating decay asymmetry parameter, alpha_b, and the helicity amplitudes for the decay Lambda_b->J/psi(mu mu)+Lambda(p pi) is reported. The analysis is based on 1400 Lambda_b and anti-Lambda_b baryons selected in 4.6/fb of proton-proton collision data with a center-of...

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Veröffentlicht in:	Physical review. D 2014, Vol.89
Hauptverfasser:	Aad, G., Albrand, S., Brown, J., Clement, B., Collot, J., Crépé-Renaudin, S., Dechenaux, B., Delsart, P.A., Gabaldon, C., Genest, M.H., Hostachy, J.Y., Le, B.T., Ledroit-Guillon, F., Lleres, A., Lucotte, A., Malek, F., Monini, C., Stark, J., Trocmé, B., Wu, M., Rahal, G., Barnovska, Z., Berger, N., Delmastro, M., Di Ciaccio, L., Doan, T.K.O., Elles, S., Goy, C., Hryn'Ova, T., Jézéquel, S., Keoshkerian, H., Lafaye, R., Leveque, J., Lombardo, V.P., Massol, N., Przysiezniak, H., Sauvage, G., Sauvan, E., Schwoerer, M., Todorov, T., Wingerter-Seez, I., Zitoun, R., Abdel Khalek, S., Augé, E., Bassalat, A., Becot, C., Binet, S., Bourdarios, C., Charfeddine, D., de La Taille, C., de Vivie de Regie, J.B., Duflot, L., Escalier, M., Fayard, L., Fournier, D., Grivaz, J.-F., Guillemin, T., Henrot-Versillé, S., Hrivnac, J., Iconomidou-Fayard, L., Idarraga, J., Kado, M., Lounis, A., Makovec, N., Matricon, P., Poggioli, L., Puzo, P., Renaud, A., Rousseau, D., Rybkin, G., Schaffer, A.C., Scifo, E., Serin, L., Simion, S., Tanaka, R., Tran, H.L., Zerwas, D., Zhang, Zhiqing, Alio, L., Barbero, M., Bertella, C., Clémens, J. C., Coadou, Y., Djama, F., Feligioni, L., Hoffmann, D., Hubaut, F., Knoops, E. B. F. G., Le Guirriec, E., Li, B., Madaffari, D., Mochizuki, K., Monnier, E., Muanza, S., Nagai, Y., Pralavorio, P., Rozanov, A., Serre, T., Talby, M., Tannoury, N.
Format:	Artikel
Sprache:	eng
Schlagworte:	High Energy Physics - Experiment Physics
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Zusammenfassung:	A measurement of the parity-violating decay asymmetry parameter, alpha_b, and the helicity amplitudes for the decay Lambda_b->J/psi(mu mu)+Lambda(p pi) is reported. The analysis is based on 1400 Lambda_b and anti-Lambda_b baryons selected in 4.6/fb of proton-proton collision data with a center-of-mass energy of 7 TeV recorded by the ATLAS experiment at the LHC. By combining the Lambda_b and anti-Lambda_b samples under the assumption of CP conservation, the value of alpha_b is measured to be 0.30+/-0.16(stat)+/-0.06(syst). This measurement provides a test of theoretical models based on perturbative QCD or heavy-quark effective theory.
ISSN:	2470-0010 2470-0029
DOI:	10.1103/PhysRevD.89.092009