First Observation of D+ →ημ+νμ and Measurement of Its Decay Dynamics

Date Issued
12-06-2020
Author(s)
Ablikim, M.
Achasov, M. N.
Adlarson, P.
Ahmed, S.
Albrecht, M.
Amoroso, A.
An, Q.
Anita,
Bai, X. H.
Bai, Y.
Bakina, O.
Baldini Ferroli, R.
Balossino, I.
Ban, Y.
Begzsuren, K.
Bennett, J. V.
Berger, N.
Bertani, M.
Bettoni, D.
Bianchi, F.
Biernat, J.
Bloms, J.
Bortone, A.
Boyko, I.
Briere, R. A.
Cai, H.
Cai, X.
Calcaterra, A.
Cao, G. F.
Cao, N.
Cetin, S. A.
Chang, J. F.
Chang, W. L.
Chelkov, G.
Chen, D. Y.
Chen, G.
Chen, H. S.
Chen, M. L.
Chen, S. J.
Chen, X. R.
Chen, Y. B.
Cheng, W. S.
Cibinetto, G.
Cossio, F.
Cui, X. F.
Dai, H. L.
Dai, J. P.
Dai, X. C.
Dbeyssi, A.
De Boer, R. B.
Dedovich, D.
Deng, Z. Y.
Denig, A.
Denysenko, I.
Destefanis, M.
De Mori, F.
Ding, Y.
Dong, C.
Dong, J.
Dong, L. Y.
Dong, M. Y.
Du, S. X.
Fang, J.
Fang, S. S.
Fang, Y.
Farinelli, R.
Fava, L.
Feldbauer, F.
Felici, G.
Feng, C. Q.
Fritsch, M.
Fu, C. D.
Fu, Y.
Gao, X. L.
Gao, Y.
Gao, Y.
Gao, Y. G.
Garzia, I.
Gersabeck, E. M.
Gilman, A.
Goetzen, K.
Gong, L.
Gong, W. X.
Gradl, W.
Greco, M.
Gu, L. M.
Gu, M. H.
Gu, S.
Gu, Y. T.
Guan, C. Y.
Guo, A. Q.
Guo, L. B.
Guo, R. P.
Guo, Y. P.
Guo, Y. P.
Guskov, A.
Han, S.
Han, T. T.
Han, T. Z.
Hao, X. Q.
DOI
Abstract
By analyzing a data sample corresponding to an integrated luminosity of 2.93 fb-1 collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we measure for the first time the absolute branching fraction of the D+→ημ+νμ decay to be BD+→ημ+νμ=(10.4±1.0stat±0.5syst)×10-4. Using the world averaged value of BD+→ηe+νe, the ratio of the two branching fractions is determined to be BD+→ημ+νμ/BD+→ηe+νe=0.91±0.13(stat+syst), which agrees with the theoretical expectation of lepton flavor universality within uncertainty. By studying the differential decay rates in five four-momentum transfer intervals, we obtain the product of the hadronic form factor f+η(0) and the c→d Cabibbo-Kobayashi-Maskawa matrix element |Vcd| to be f+η(0)|Vcd|=0.087±0.008stat±0.002syst. Taking the input of |Vcd| from the global fit in the standard model, we determine f+η(0)=0.39±0.04stat±0.01syst. On the other hand, using the value of f+η(0) calculated in theory, we find |Vcd|=0.242±0.022stat±0.006syst±0.033theory.
Volume
124