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Статья

Ablikim, M.
Observation of D*+&sub(s)*>*h'*m*n&sub(*m), Precision Test of Lepton Flavor Universality with D*+&sub(s)*>*h&sup(('))l*+*n&sub(l), and First Measurements of D*+&sub(s)*>*h&sup(('))*m*+*n&sub(*m) Decay Dynamics / M.Ablikim, O.Bakina, I.Boyko, G.Chelkov, D.Dedovich, I.Denysenko, P.Egorov, A.Guskov, Y.Nefedov, S.Pogodin, A.Sarantsev, A.Zhemchugov, [a.o.] // Physical Review Letters [Electronic resource]. – 2024. – Vol. 132, No. 9. – P. 091802. – URL: https://doi.org/10.1103/PhysRevLett.132.091802. – Bibliogr.: 71.

By analyzing 7.33 fb−1 of eþe− annihilation data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we report the observation of the semileptonic decay Dþ s → η0μþν μ, with a statistical significance larger than 10σ, and the measurements of the Dþ s → ημþνμ and Dþ s → η0μþν μ decay dynamics for the first time. The branching fractions of Dþ s → ημþν μ and Dþ s → η0μþν μ are determined to be ð2.235 *( 0.051stat *( 0.052systÞ% and ð0.801 *( 0.055stat *( 0.028systÞ%, respectively, with precision improved by factors of 6.0 and 6.6 compared to the previous best measurements. Combined with the results for the decays Dþ s → ηeþνe and Dþ s → η0eþνe, the ratios of the decay widths are examined both inclusively and in several lþνl four-momentum transfer ranges. No evidence for lepton flavor universality violation is found within the current statistics. The products of the hadronic form factors fηð0Þ þ;0ð0Þ and the c → s Cabibbo-Kobayashi-Maskawa matrix element jV csj are determined. The results based on the two-parameter series expansion are fη þ;0ð0ÞjV csj ¼ 0.452 *( 0.010stat *( 0.007syst and fη0 þ;0ð0ÞjV csj ¼ 0.504 *( 0.037stat *( 0.012syst , which help to constrain present models on fηð0Þ þ;0ð0Þ. The forward-backward asymmetries are determined to be hAη FBi ¼ −0.059 *( 0.031stat *( 0.005syst and hAη0 FBi ¼ −0.064 *( 0.079stat *( 0.006syst for the first time, which are consistent with the theoretical calculation.



ОИЯИ = ОИЯИ (JINR)2024
Спец.(статьи,препринты) = С 346.6е1 - Рождение прямых лептонов в соударениях элементарных частиц. Новые лептоны. Тау- лептон