Research output: Contribution to journal › Article › peer-review
Test of lepton flavor universality by the measurement of the B0 →d∗-τ+ντ branching fraction using three-prong τ decays. / The LHCb Collaboration.
In: Physical Review D, Vol. 97, No. 7, 072013, 25.04.2018.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Test of lepton flavor universality by the measurement of the B0 →d∗-τ+ντ branching fraction using three-prong τ decays
AU - The LHCb Collaboration
AU - Aaij, R.
AU - Adeva, B.
AU - Adinolfi, M.
AU - Ajaltouni, Z.
AU - Akar, S.
AU - Albrecht, J.
AU - Alessio, F.
AU - Alexander, M.
AU - Alfonso Albero, A.
AU - Ali, S.
AU - Alkhazov, G.
AU - Alvarez Cartelle, P.
AU - Alves, A. A.
AU - Amato, S.
AU - Amerio, S.
AU - Amhis, Y.
AU - An, L.
AU - Anderlini, L.
AU - Andreassi, G.
AU - Andreotti, M.
AU - Andrews, J. E.
AU - Appleby, R. B.
AU - Archilli, F.
AU - D'Argent, P.
AU - Arnau Romeu, J.
AU - Artamonov, A.
AU - Artuso, M.
AU - Aslanides, E.
AU - Auriemma, G.
AU - Baalouch, M.
AU - Babuschkin, I.
AU - Bachmann, S.
AU - Back, J. J.
AU - Badalov, A.
AU - Baesso, C.
AU - Baker, S.
AU - Balagura, V.
AU - Baldini, W.
AU - Baranov, A.
AU - Barlow, R. J.
AU - Barschel, C.
AU - Barsuk, S.
AU - Barter, W.
AU - Baryshnikov, F.
AU - Batozskaya, V.
AU - Battista, V.
AU - Bay, A.
AU - Beaucourt, L.
AU - Beddow, J.
AU - Shekhtman, L.
N1 - Funding Information: We express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); MOST and NSFC (China); CNRS/IN2P3 (France); BMBF, DFG and MPG (Germany); INFN (Italy); NWO (The Netherlands); MNiSW and NCN (Poland); MEN/IFA (Romania); MinES and FASO (Russia); MinECo (Spain); SNSF and SER (Switzerland); NASU (Ukraine); STFC (United Kingdom); NSF (U.S.). We acknowledge the computing resources that are provided by CERN, IN2P3 (France), KIT and DESY (Germany), INFN (Italy), SURF (The Netherlands), PIC (Spain), GridPP (United Kingdom), RRCKI and Yandex LLC (Russia), CSCS (Switzerland), IFIN-HH (Romania), CBPF (Brazil), PL-GRID (Poland) and OSC (U.S.). We are indebted to the communities behind the multiple open-source software packages on which we depend. Individual groups or members have received support from AvH Foundation (Germany), EPLANET, Marie Skłodowska-Curie Actions and ERC (European Union), ANR, Labex P2IO, ENIGMASS and OCEVU, and Région Auvergne-Rhône-Alpes (France), RFBR and Yandex LLC (Russia), GVA, XuntaGal and GENCAT (Spain), Herchel Smith Fund, the Royal Society, the English-Speaking Union and the Leverhulme Trust (United Kingdom). Publisher Copyright: © 2018 CERN, for the LHCb Collaboration. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP.
PY - 2018/4/25
Y1 - 2018/4/25
N2 - The ratio of branching fractions R(D∗-)≡B(B0→D∗-τ+ντ)/B(B0→D∗-μ+νμ) is measured using a data sample of proton-proton collisions collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb-1. The τ lepton is reconstructed with three charged pions in the final state. A novel method is used that exploits the different vertex topologies of signal and backgrounds to isolate samples of semitauonic decays of b hadrons with high purity. Using the B0→D∗-π+π-π+ decay as the normalization channel, the ratio B(B0→D∗-τ+ντ)/B(B0→D∗-π+π-π+) is measured to be 1.97±0.13±0.18, where the first uncertainty is statistical and the second systematic. An average of branching fraction measurements for the normalization channel is used to derive B(B0→D∗-τ+ντ)=(1.42±0.094±0.129±0.054)%, where the third uncertainty is due to the limited knowledge of B(B0→D∗-π+π-π+). A test of lepton flavor universality is performed using the well-measured branching fraction B(B0→D∗-μ+νμ) to compute R(D∗-)=0.291±0.019±0.026±0.013, where the third uncertainty originates from the uncertainties on B(B0→D∗-π+π-π+) and B(B0→D∗-μ+νμ). This measurement is in agreement with the Standard Model prediction and with previous measurements.
AB - The ratio of branching fractions R(D∗-)≡B(B0→D∗-τ+ντ)/B(B0→D∗-μ+νμ) is measured using a data sample of proton-proton collisions collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb-1. The τ lepton is reconstructed with three charged pions in the final state. A novel method is used that exploits the different vertex topologies of signal and backgrounds to isolate samples of semitauonic decays of b hadrons with high purity. Using the B0→D∗-π+π-π+ decay as the normalization channel, the ratio B(B0→D∗-τ+ντ)/B(B0→D∗-π+π-π+) is measured to be 1.97±0.13±0.18, where the first uncertainty is statistical and the second systematic. An average of branching fraction measurements for the normalization channel is used to derive B(B0→D∗-τ+ντ)=(1.42±0.094±0.129±0.054)%, where the third uncertainty is due to the limited knowledge of B(B0→D∗-π+π-π+). A test of lepton flavor universality is performed using the well-measured branching fraction B(B0→D∗-μ+νμ) to compute R(D∗-)=0.291±0.019±0.026±0.013, where the third uncertainty originates from the uncertainties on B(B0→D∗-π+π-π+) and B(B0→D∗-μ+νμ). This measurement is in agreement with the Standard Model prediction and with previous measurements.
KW - SIMULATION
KW - LEPTOQUARKS
KW - ENERGY
UR - http://www.scopus.com/inward/record.url?scp=85046270882&partnerID=8YFLogxK
U2 - 10.1103/PhysRevD.97.072013
DO - 10.1103/PhysRevD.97.072013
M3 - Article
AN - SCOPUS:85046270882
VL - 97
JO - Physical Review D
JF - Physical Review D
SN - 2470-0010
IS - 7
M1 - 072013
ER -
ID: 13331304