We measure the tau-to-light-lepton ratio of inclusive B-meson branching fractions R(Xτ/ℓ)B(B→Xτν)/B(B→Xℓν), where ℓ indicates an electron or muon, and thereby test the universality of charged-current weak interactions. We select events that have one fully reconstructed B meson and a charged lepton candidate from 189 fb-1 of electron-positron collision data collected with the Belle II detector. We find R(Xτ/ℓ)=0.228±0.016(stat)±0.036(syst), in agreement with standard-model expectations. This is the first direct measurement of R(Xτ/ℓ).

First Measurement of R (Xτ/ℓ) as an Inclusive Test of the b →cτν Anomaly / Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Aihara, H., Akopov, N., Aloisio, A., Asner, D.M., Atmacan, H., Aushev, T., Aushev, V., Aversano, M., Babu, V., Bahinipati, S., Bambade, P., Banerjee, S., Bansal, S., Barrett, M., Baudot, J., Baur, A., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 132:21(2024). [10.1103/PhysRevLett.132.211804]

First Measurement of R (Xτ/ℓ) as an Inclusive Test of the b →cτν Anomaly

Aloisio A.;Campajola M.;De Nardo G.;Di Capua F.;Gaudino G.;Giordano R.;Merola M.;Mirra M.;Pardi S.;Russo Guido;
2024

Abstract

We measure the tau-to-light-lepton ratio of inclusive B-meson branching fractions R(Xτ/ℓ)B(B→Xτν)/B(B→Xℓν), where ℓ indicates an electron or muon, and thereby test the universality of charged-current weak interactions. We select events that have one fully reconstructed B meson and a charged lepton candidate from 189 fb-1 of electron-positron collision data collected with the Belle II detector. We find R(Xτ/ℓ)=0.228±0.016(stat)±0.036(syst), in agreement with standard-model expectations. This is the first direct measurement of R(Xτ/ℓ).
2024
First Measurement of R (Xτ/ℓ) as an Inclusive Test of the b →cτν Anomaly / Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Aihara, H., Akopov, N., Aloisio, A., Asner, D.M., Atmacan, H., Aushev, T., Aushev, V., Aversano, M., Babu, V., Bahinipati, S., Bambade, P., Banerjee, S., Bansal, S., Barrett, M., Baudot, J., Baur, A., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 132:21(2024). [10.1103/PhysRevLett.132.211804]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/968992
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