The longitudinal polarization fraction of the D* meson is measured in B0 → D*− τ+ ν_τ decays, where the τ lepton decays to three charged pions and a neutrino, using proton-proton collision data collected by the LHCb experiment at center-of-mass energies of 7, 8 and 13 TeV and corresponding to an integrated luminosity of 5 fb^−1. The D* polarization fraction F_L^D* is measured in two q^2 regions, below and above 7 GeV^2/c^4, where q^2 is defined as the squared invariant mass of the τ ν_τ system. The F_L^D* values are measured to be 0.52 ± 0.07 ± 0.04 and 0.34 ± 0.08 ± 0.02 for the lower and higher q^2 regions, respectively. The first uncertainties are statistical and the second systematic. The average value over the whole q^2 range is: F_L^D* = 0.41 ± 0.06 ± 0.03. These results are compatible with the Standard Model predictions.

Aaij, R., Abdelmotteleb, A. . ., Abellan Beteta, C., Abudinén, F., Ackernley, T., Adeva, B., et al. (2024). Measurement of the D* longitudinal polarization in B0 → D*− τ+ ν_τ decays. PHYSICAL REVIEW D, 110(9), 1-18 [10.1103/physrevd.110.092007].

Measurement of the D* longitudinal polarization in B0 → D*− τ+ ν_τ decays

Carbone, A.;Ferrari, F.;Galli, D.;Patrignani, C.;Spedicato, E.;Villa, A.;
2024

Abstract

The longitudinal polarization fraction of the D* meson is measured in B0 → D*− τ+ ν_τ decays, where the τ lepton decays to three charged pions and a neutrino, using proton-proton collision data collected by the LHCb experiment at center-of-mass energies of 7, 8 and 13 TeV and corresponding to an integrated luminosity of 5 fb^−1. The D* polarization fraction F_L^D* is measured in two q^2 regions, below and above 7 GeV^2/c^4, where q^2 is defined as the squared invariant mass of the τ ν_τ system. The F_L^D* values are measured to be 0.52 ± 0.07 ± 0.04 and 0.34 ± 0.08 ± 0.02 for the lower and higher q^2 regions, respectively. The first uncertainties are statistical and the second systematic. The average value over the whole q^2 range is: F_L^D* = 0.41 ± 0.06 ± 0.03. These results are compatible with the Standard Model predictions.
2024
Aaij, R., Abdelmotteleb, A. . ., Abellan Beteta, C., Abudinén, F., Ackernley, T., Adeva, B., et al. (2024). Measurement of the D* longitudinal polarization in B0 → D*− τ+ ν_τ decays. PHYSICAL REVIEW D, 110(9), 1-18 [10.1103/physrevd.110.092007].
Aaij, R.; Abdelmotteleb, A.  S.  W.; Abellan Beteta, C.; Abudinén, F.; Ackernley, T.; Adeva, B.; Adinolfi, M.; Adlarson, P.; Afsharnia, H.; Agapopoulo...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/1002613
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