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.

Test of lepton flavor universality by the measurement of the B0 →d∗-τ+ντ branching fraction using three-prong τ decays / Aaij, R., Adeva, B., Adinolfi, M., Ajaltouni, Z., Akar, S., Albrecht, J., Alessio, F., Alexander, M., Alfonso Albero, A., Ali, S., Alkhazov, G., Alvarez Cartelle, P., Alves, A.A., Amato, S., Amerio, S., Amhis, Y., An, L., Anderlini, L., Andreassi, G., Andreotti, M., et al.. - In: PHYSICAL REVIEW D. - ISSN 2470-0010. - 97:7(2018), pp. N/A-N/A. [10.1103/PhysRevD.97.072013]

Test of lepton flavor universality by the measurement of the B0 →d∗-τ+ντ branching fraction using three-prong τ decays

Bizzeti A.;
2018

Abstract

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.
2018
97
7
N/A
N/A
Test of lepton flavor universality by the measurement of the B0 →d∗-τ+ντ branching fraction using three-prong τ decays / Aaij, R., Adeva, B., Adinolfi, M., Ajaltouni, Z., Akar, S., Albrecht, J., Alessio, F., Alexander, M., Alfonso Albero, A., Ali, S., Alkhazov, G., Alvarez Cartelle, P., Alves, A.A., Amato, S., Amerio, S., Amhis, Y., An, L., Anderlini, L., Andreassi, G., Andreotti, M., et al.. - In: PHYSICAL REVIEW D. - ISSN 2470-0010. - 97:7(2018), pp. N/A-N/A. [10.1103/PhysRevD.97.072013]
Aaij, R.; Adeva, B.; Adinolfi, M.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Alfonso Albero, A.; Ali, S.; Alkhazov, G.; Alvar...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1209760
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