Widhalm, L.Adachi, I.Aihara, H.Aushev, T.Bakich, A.M.Balagura, V.Barberio, E.Bay, A.Bedny, I.Bhardwaj, V.Bitenc, U.Blyth, S.Bozek, A.Bračko, M.Brodzicka, J.Browder, T.E.Chao, Y.Chen, A.Chen, W.T.Cheon, B.G.Chistov, R.Cho, I.-S.Choi, Y.Dalseno, J.Dash, M.Drutskoy, A.Eidelman, S.Goldenzweig, P.Golob, B.Ha, H.Haba, J.Hayasaka, K.Hayashii, H.Hazumi, M.Heffernan, D.Hoshi, Y.Hou, W.-S.Hsiung, Y.B.Hyun, H.J.Iijima, T.Inami, K.Ishikawa, A.Ishino, H.Itoh, R.Iwasaki, M.Iwasaki, Y.Kah, D.H.Kang, J.H.Kapusta, P.Katayama, N.Kawai, H.Kawasaki, T.Kichimi, H.Kim, S.K.Kim, Y.J.Kinoshita, K.Korpar, S.Križan, P.Krokovny, P.Kumar, R.Kuo, C.C.Kuroki, Y.Kuzmin, A.Kwon, Y.-J.Lee, J.Lee, J.S.Lee, M.J.Lee, S.E.Lesiak, T.Lin, S.-W.Liu, C.Liventsev, D.Mandl, F.Matyja, A.McOnie, S.Mitaroff, W.Miyake, H.Miyata, H.Miyazaki, Y.Mizuk, R.Moloney, G.R.Nakano, E.Nakao, M.Natkaniec, Z.Nishida, S.Nitoh, O.Noguchi, S.Ogawa, S.Ohshima, T.Okuno, S.Ozaki, H.Pakhlov, P.Pakhlova, G.Palka, H.Park, C.W.Park, H.Park, K.S.Peak, L.S.Pestotnik, R.Piilonen, L.E.Sahoo, H.Sakai, Y.Schneider, O.Seidl, R.Sekiya, A.Senyo, K.Shapkin, M.Shibuya, H.Shiu, J.-G.Singh, J.B.Somov, A.Stanič, S.Starič, M.Sumiyoshi, T.Suzuki, S.Y.Takasaki, F.Tamura, N.Tanaka, M.Taylor, G.N.Teramoto, Y.Tikhomirov, I.Trabelsi, K.Uehara, S.Uglov, T.Unno, Y.Uno, S.Urquijo, P.Usov, Y.Varner, G.Vervink, K.Wang, C.H.Wang, M.-Z.Wang, P.Watanabe, Y.Wedd, R.Won, E.Yabsley, B.D.Yamamoto, H.Yamashita, Y.Zhang, Z.P.Zhilich, V.Zupanc, A.Zyukova, O.2010-11-052010-11-052010-11-05200810.1103/PhysRevLett.100.2418012-s2.0-45549098438https://infoscience.epfl.ch/handle/20.500.14299/56939WOS:000256942400017We present a measurement of the branching fraction B(Ds+→μ+νμ ) using a 548fb-1 data sample collected by the Belle experiment at the KEKB e+e- collider. The Ds momentum is determined by reconstruction of the system recoiling against DKγX in events of the type e+e-→Ds*DKX, Ds*→Dsγ, where X represents additional pions or photons from fragmentation. This full-reconstruction method provides high resolution in the neutrino momentum and thus good background separation, equivalent to that achieved by experiments at the tau-charm factories. We obtain the branching fraction B(Ds+→μ+νμ)=[6.44±0.76(stat)±0.57(syst)] ×10-3, implying a Ds decay constant of fDs=[275±16(stat) ±12(syst)]MeV. © 2008 The American Physical Society.text::journal::journal article::research article