First observation of the decay D0→K−π+μ+μ− in the ρ0–ω region of the dimuon mass spectrum

• Published in: Physics letters. B 2016-06, Vol.757 (C), p.558-567
• Main Authors: Andreotti, M., Andrews, J.E., Back, J.J., Barschel, C., Barter, W., Bay, A., Beddow, J., Belyaev, I., Ben-Haim, E., Brodzicka, J., Bursche, A., Calabrese, R., Calvi, M., Cardinale, R., Cauet, Ch, Cenci, R., Charles, M., Charpentier, Ph, Chrzaszcz, M., Clarke, P.E.L., Coco, V., De Bruyn, K., De Simone, P., Decamp, D., Dosil Suárez, A., Dufour, L., Durante, P., Eitschberger, U., Evans, H.M., Fiorini, M., Frank, M., Frosini, M., Gallas Torreira, A., Gandelman, M., Gao, Y., Göbel, C., Gregson, S., Griffith, P., Harnew, N., He, J., Humair, T., John, M., Joram, C., Kandybei, S., Kanso, W., Ketel, T., Klimaszewski, K., Kreps, M., Kuonen, A.K., Langhans, B., Lefèvre, R., Lindner, R., Longstaff, I., Malinin, A., Martinez Santos, D., McNulty, R., Meier, F., Monteil, S., Morawski, P., Morello, M.J., Neri, N., Neubert, S., Nikitin, N., Okhrimenko, O., Oldeman, R., Palombo, F., Panman, J., Papanestis, A., Patel, M., Pepe Altarelli, M., Pistone, A., Polycarpo, E., Price, J.D., Prouve, C., Rauschmayr, N., Richards, S., Romanovsky, V., Sanmartin Sedes, B., Santovetti, E., Satriano, C., Sciascia, B., Shcheglov, Y., Skidmore, N., Skwarnicki, T., Soler, F.J.P., Sridharan, S., Stagni, F., Stoica, S., Sutcliffe, W., Szczekowski, M., T'Jampens, S., Ukleja, A., Uwer, U., Vallier, A., van Veghel, M., Veneziano, G., Vesterinen, M., Volyanskyy, D., Voong, D., Walsh, J.
• Format: Article
• Language: English
• Subjects: High Energy Physics - Experiment; Physics; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2016.04.029

A study of the decay D0→K−π+μ+μ− is performed using data collected by the LHCb detector in proton–proton collisions at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 2.0 fb−1. Decay candidates with muon pairs that have an invariant mass in the range 675–875 MeV/c2 are considered. This region is dominated by the ρ0 and ω resonances. The branching fraction in this range is measured to beB(D0→K−π+μ+μ−)=(4.17±0.12(stat)±0.40(syst))×10−6. This is the first observation of the decay D0→K−π+μ+μ−. Its branching fraction is consistent with the value expected in the Standard Model.