@article{b4a55f3704684ebca44931579e2687ad,
title = "First Observation of D+ →ημ+νμ and Measurement of Its Decay Dynamics",
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.",
author = "{BESIII Collaboration} and M. Ablikim and Achasov, {M. N.} and P. Adlarson and S. Ahmed and M. Albrecht and A. Amoroso and Q. An and Anita and Bai, {X. H.} and Y. Bai and O. Bakina and {Baldini Ferroli}, R. and I. Balossino and Y. Ban and K. Begzsuren and Bennett, {J. V.} and N. Berger and M. Bertani and D. Bettoni and F. Bianchi and J. Biernat and J. Bloms and A. Bortone and I. Boyko and Briere, {R. A.} and H. Cai and X. Cai and A. Calcaterra and Cao, {G. F.} and N. Cao and Cetin, {S. A.} and Chang, {J. F.} and Chang, {W. L.} and G. Chelkov and Chen, {D. Y.} and G. Chen and Chen, {H. S.} and Chen, {M. L.} and Chen, {S. J.} and Chen, {X. R.} and Chen, {Y. B.} and Cheng, {W. S.} and G. Cibinetto and F. Cossio and Cui, {X. F.} and Dai, {H. L.} and Dai, {J. P.} and Dai, {X. C.} and Muchnoi, {N. Yu} and Nikolaev, {I. B.}",
note = "Publisher Copyright: {\textcopyright} 2020 authors. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.",
year = "2020",
month = jun,
day = "12",
doi = "10.1103/PhysRevLett.124.231801",
language = "English",
volume = "124",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "23",
}