Measurement of the isospin asymmetry in B → K()μ+μ− decays

• Published in: The journal of high energy physics 2012-07, Vol.2012 (7), Article 133
• Main Authors: Adametz, A., Adrover, C., Ajaltouni, Z., Alessio, F., Barter, W., Benson, S., Benton, J., Bifani, S., Blusk, S., van den Brand, J., Cardini, A., Ciezarek, G., Clemencic, M., Collins, P., Cook, A., Coombes, M., D’Ambrosio, C., De Bonis, I., Dzhelyadin, R., Eidelman, S., Eisele, F., Ekelhof, R., El Rifai, I., Falabella, A., Furcas, S., Gandini, P., Gersabeck, M., Gándara, M. Grabalosa, Cardoso, L. A. Granado, Greening, E., Haefeli, G., Hansmann-Menzemer, S., Henrard, P., Morata, J. A. Hernando, Hicks, E., Hopchev, P., Huse, T., Jacobsson, R., Jansen, F., Kandybei, S., Karacson, M., Kim, Y. M., Kochebina, O., Komarov, I., Kozlinskiy, A., Kreps, M., Krocker, G., Krokovny, P., Kruse, F., Kvaratskheliya, T., Lafferty, G., Lambert, R. W., Leflat, A., Liles, M., Lindner, R., Liu, B., Asamar, E. Lopez, Magnin, J., Martin, L., Martinelli, M., Santos, D. Martinez, Needham, M., Goicochea, J. M. Otalora, Owen, P., Palutan, M., Pappagallo, M., Parkes, C., Parkinson, C. J., Patel, G. D., Perego, D. L., Valls, B. Pie, Popov, D., Rangel, M. S., Redford, S., Ricciardi, S., Rinnert, K., Robbe, P., Romanovsky, V., Silva, J. J. Saborido, Sedes, B. Sanmartin, Santacesaria, R., Schiller, M., Schmelling, M., Skwarnicki, T., Smith, N. A., Souza, D., Sparkes, A., Spradlin, P., Stahl, S., Storaci, B., Subbiah, V. K., Szczekowski, M., Teubert, F., Tournefier, E., Voong, D., Vorobyev, A., Voss, H., Watson, N. K., Wright, S., Zavertyaev, M.
• Format: Article
• Language: English
• Subjects: Asymmetry; Classical and Quantum Gravitation; Decay; Elementary Particles; Gran Col·lisionador d'Hadrons; Gravitació; Gravitation; Hadrons; High energy physics; High Energy Physics - Experiment; Large Hadron Collider (France and Switzerland); Luminosity; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Quantum theory; Relativitat (Física); Relativity (Physics); Relativity Theory; String Theory; Teoria quàntica; Teoria quàntica de camps
• ISSN: 1029-8479; 1126-6708; 1029-8479
• DOI: 10.1007/JHEP07(2012)133

A bstract The isospin asymmetries of B  →  K (∗) μ + μ − decays and the partial branching fractions of B 0  →  K 0 μ + μ − and B +  →  K ∗+ μ + μ − are measured as a function of the di-muon mass squared q 2 using an integrated luminosity of 1.0 fb −1 collected with the LHCb detector. The B  →  Kμ + μ − isospin asymmetry integrated over q 2 is negative, deviating from zero with over 4 σ significance. The B  →  K ∗ μ + μ − decay measurements are consistent with the Standard Model prediction of negligible isospin asymmetry. The observation of the decay B 0  →  K S μ + μ − is reported with 5.7 σ significance. Assuming that the branching fraction of B 0  →  K 0 μ + μ − is twice that of B 0  →  K S μ + μ − , the branching fractions of B 0  →  K 0 μ + μ − and B  →  K ∗+ μ + μ − are found to be (0 . 31 −0.06 ) × 10 −6 and (1 . 16 ± 0 . 19) × 10 −6 , respectively.