Search for $B^+ \to \mu^+\, \nu_\mu$ and $B^+ \to \mu^+\, N$ with inclusive tagging

M. t. Prim , F. u. Bernlochner , P. Goldenzweig , M. Heck , I. Adachi , K. Adamczyk , H. Aihara , S. Al Said , D. m. Asner , H. Atmacan , V. Aulchenko , T. Aushev , R. Ayad , V. Babu , A. m. Bakich , V. Bansal , P. Behera , C. Beleño , V. Bhardwaj , B. Bhuyan , T. Bilka , J. Biswal , A. Bobrov , A. Bozek , M. Bračko , N. Braun , T. e. Browder , M. Campajola , L. Cao , D. Červenkov , P. Chang , V. Chekelian , A. Chen , B. g. Cheon , K. Chilikin , H. e. Cho , K. Cho , Y. Choi , S. Choudhury , D. Cinabro , S. Cunliffe , Z. Doležal , S. Eidelman , D. Epifanov , J. e. Fast , T. Ferber , B. g. Fulsom , R. Garg , V. Gaur , A. Garmash , A. Giri , O. Grzymkowska , Y. Guan , J. Haba , T. Hara , K. Hayasaka , H. Hayashii , W.-S. Hou , T. Iijima , K. Inami , G. Inguglia , A. Ishikawa , M. Iwasaki , Y. Iwasaki , S. Jia , Y. Jin , D. Joffe , K. k. Joo , A. b. Kaliyar , G. Karyan , T. Kawasaki , H. Kichimi , C. Kiesling , C. h. Kim , D. y. Kim , K. t. Kim , S. h. Kim , K. Kinoshita , P. Kodyš , S. Korpar , D. Kotchetkov , P. Križan , R. Kroeger , P. Krokovny , T. Kuhr , R. Kulasiri , R. Kumar , T. Kumita , A. Kuzmin , Y.-J. Kwon , K. Lalwani , J. s. Lange , I. s. Lee , J. k. Lee , J. y. Lee , S. c. Lee , P. Lewis , C. h. Li , L. Li Gioi , J. Libby , K. Lieret , D. Liventsev , P.-C. Lu , T. Luo , J. Macnaughton , M. Masuda , T. Matsuda , D. Matvienko , M. Merola , F. Metzner , K. Miyabayashi , R. Mizuk , G. b. Mohanty , R. Mussa , M. Nakao , G. de Nardo , K. j. Nath , Z. Natkaniec , M. Nayak , M. Niiyama , N. k. Nisar , S. Nishida , K. Nishimura , S. Ogawa , H. Ono , Y. Onuki , P. Pakhlov , G. Pakhlova , B. Pal , S. Pardi , H. Park , S.-H. Park , S. Patra , S. Paul , T. k. Pedlar , R. Pestotnik , L. e. Piilonen , V. Popov , E. Prencipe , M. Ritter , A. Rostomyan , M. Rozanska , G. Russo , D. Sahoo , Y. Sakai , L. Santelj , V. Savinov , O. Schneider , G. Schnell , J. Schueler , C. Schwanda , Y. Seino , K. Senyo , M. e. Sevior , V. Shebalin , J.-G. Shiu , B. Shwartz , F. Simon , A. Sokolov , E. Solovieva , M. Starič , J. f. Strube , M. Sumihama , T. Sumiyoshi , W. Sutcliffe , M. Takizawa , U. Tamponi , Y. Tao , F. Tenchini , Karim Trabelsi (1) , M. Uchida , T. Uglov , Y. Unno , S. Uno , Y. Ushiroda , Y. Usov , S. e. Vahsen , R. van Tonder , G. Varner , K. e. Varvell , A. Vinokurova , Biao Wang , C. h. Wang , M.-Z. Wang , P. Wang , S. Watanuki , E. Won , S. b. Yang , H. Ye , J. h. Yin , Y. Yusa , Z. p. Zhang , V. Zhilich , V. Zhukova , V. Zhulanov

1 IJCLab - Laboratoire de Physique des 2 Infinis Irène Joliot-Curie

We report the result for a search for the leptonic decay of B+→μ+νμ using the full Belle data set of 711 fb−1 of integrated luminosity at the Υ(4S) resonance. In the Standard Model leptonic B-meson decays are helicity and CKM suppressed. To maximize sensitivity an inclusive tagging approach is used to reconstruct the second B meson produced in the collision. The directional information from this second B meson is used to boost the observed μ into the signal B meson rest-frame, in which the μ has a monochromatic momentum spectrum. Though its momentum is smeared by the experimental resolution, this technique improves the analysis sensitivity considerably. Analyzing the μ momentum spectrum in this frame we find B(B+→μ+νμ)=(5.3±2.0±0.9)×10−7 with a one-sided significance of 2.8 standard deviations over the background-only hypothesis. This translates to a frequentist upper limit of B(B+→μ+νμ)<8.6×10−7 at 90% CL. The experimental spectrum is then used to search for a massive sterile neutrino, B+→μ+N, but no evidence is observed for a sterile neutrino with a mass in a range of 0 - 1.5 GeV. The determined B+→μ+νμ branching fraction limit is further used to constrain the mass and coupling space of the type II and type III two-Higgs-doublet models.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]

M. t. Prim, F. u. Bernlochner, P. Goldenzweig, M. Heck, I. Adachi, et al.. Search for $B^+ \to \mu^+\, \nu_\mu$ and $B^+ \to \mu^+\, N$ with inclusive tagging. Physical Review D, 2020, 101, pp.032007. ⟨10.1103/PhysRevD.101.032007⟩. ⟨hal-03098932⟩