Wehle S, Adachi I, Adamczyk K, Aihara H, Asner D M, Atmacan H, Aulchenko V, Aushev T, Ayad R, Babu V, Behera P, Berger M, Bhardwaj V, Biswal J, Bozek A, Bračko M, Browder T E, Campajola M, Cao L, Chang M-C, Chen A, Cheon B G, Chilikin K, Cho K, Choi Y, Choudhury S, Cinabro D, Cunliffe S, Dash N, De Nardo G, Di Capua F, Dubey S, Eidelman S, Epifanov D, Ferber T, Fulsom B G, Garg R, Gaur V, Gabyshev N, Garmash A, Giri A, Goldenzweig P, Greenwald D, Guan Y, Haba J, Hartbrich O, Hayasaka K, Hayashii H, Hedges M T, Higuchi T, Hou W-S, Hsu C-L, Iijima T, Inami K, Inguglia G, Ishikawa A, Itoh R, Iwasaki M, Iwasaki Y, Jacobs W W, Jia S, Jin Y, Joffe D, Kahn J, Kaliyar A B, Karyan G, Kichimi H, Kim D Y, Kim K T, Kim S H, Kim Y-K, Kinoshita K, Komarov I, Korpar S, Kotchetkov D, Kroeger R, Krokovny P, Kuhr T, Kulasiri R, Kumar R, Kumara K, Kuzmin A, Kwon Y-J, Lange J S, Lee J Y, Lee S C, Li Y B, Libby J, Liptak Z, Liventsev D, Luo T, MacNaughton J, Masuda M, Matsuda T, McNeil J T, Merola M, Metzner F, Miyata H, Mizuk R, Mohanty G B, Moon T J, Mussa R, Nakao M, Natochii A, Nayak M, Niebuhr C, Niiyama M, Nisar N K, Nishida S, Ogawa K, Ogawa S, Ono H, Onuki Y, Pakhlov P, Pakhlova G, Park H, Park S-H, Pedlar T K, Pestotnik R, Piilonen L E, Podobnik T, Popov V, Prencipe E, Prim M T, Resmi P K, Ritter M, Rostomyan A, Rout N, Russo G, Sahoo D, Sakai Y, Sandilya S, Sangal A, Santelj L, Savinov V, Schneider O, Schnell G, Schueler J, Schwanda C, Schwartz A J, Seino Y, Senyo K, Sevior M E, Shapkin M, Shiu J-G, Shwartz B, Solovieva E, Starič M, Strube J F, Sumiyoshi T, Sutcliffe W, Takizawa M, Tamponi U, Tanida K, Tao Y, Tenchini F, Trabelsi K, Uchida M, Uglov T, Unno Y, Uno S, Ushiroda Y, Vahsen S E, Van Tonder R, Varner G, Varvell K E, Vorobyev V, Wang C H, Wang M-Z, Wang P, Wang X L, Won E, Xu X, Yang S B, Ye H, Yin J H, Yuan C Z, Zhang Z P, Zhilich V, Zhukova V, Zhulanov V
Deutsches Elektronen-Synchrotron, 22607 Hamburg.
SOKENDAI (The Graduate University for Advanced Studies), Hayama 240-0193.
Phys Rev Lett. 2021 Apr 23;126(16):161801. doi: 10.1103/PhysRevLett.126.161801.
We present a measurement of R_{K^{}}, the branching fraction ratio B(B→K^{}μ^{+}μ^{-})/B(B→K^{}e^{+}e^{-}), for both charged and neutral B mesons. The ratio for the charged case R_{K^{+}} is the first measurement ever performed. In addition, we report absolute branching fractions for the individual modes in bins of the squared dilepton invariant mass q^{2}. The analysis is based on a data sample of 711 fb^{-1}, containing 772×10^{6} BB[over ¯] events, recorded at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. The obtained results are consistent with standard model expectations.
我们给出了带电和中性B介子的R_{K^{}}的测量结果，即分支比B(B→K^{}μ^{+}μ^{-})/B(B→K^{}e^{+}e^{-})。带电情况的比率R_{K^{+}}是有史以来首次进行的测量。此外，我们报告了双轻子不变质量平方q^{2}区间内各个模式的绝对分支比。该分析基于在KEKB非对称能量e^{+}e^{-}对撞机上，利用Belle探测器在ϒ(4S)共振处记录的711 fb^{-1}的数据样本，其中包含772×10^{6}个BB[上划线]事件。所得结果与标准模型预期一致。
