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. s. w., 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. s. w., 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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