The longitudinal polarization fraction of the D* meson is measured in B0→D*-τ+ντ 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 FLD* is measured in two q2 regions, below and above 7 GeV2/c4, where q2 is defined as the squared invariant mass of the τντ system. The FLD∗ values are measured to be 0.52±0.07±0.04 and 0.34±0.08±0.02 for the lower and higher q2 regions, respectively. The first uncertainties are statistical and the second systematic. The average value over the whole q2 range is FLD∗=0.41±0.06±0.03. These results are compatible with the Standard Model predictions.

Measurement of the D* longitudinal polarization in B0 →d*-τ+ντ decays

Bassi G.
Membro del Collaboration Group
;
Kleijne N.
Membro del Collaboration Group
;
Morello M. J.
Membro del Collaboration Group
;
Passaro D.
Membro del Collaboration Group
;
Pica L.
Membro del Collaboration Group
;
Ribatti R.
Membro del Collaboration Group
;
Riccardi D.
Membro del Collaboration Group
;
2024

Abstract

The longitudinal polarization fraction of the D* meson is measured in B0→D*-τ+ντ 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 FLD* is measured in two q2 regions, below and above 7 GeV2/c4, where q2 is defined as the squared invariant mass of the τντ system. The FLD∗ values are measured to be 0.52±0.07±0.04 and 0.34±0.08±0.02 for the lower and higher q2 regions, respectively. The first uncertainties are statistical and the second systematic. The average value over the whole q2 range is FLD∗=0.41±0.06±0.03. These results are compatible with the Standard Model predictions.
2024
Settore FIS/01 - Fisica Sperimentale
Settore PHYS-01/A - Fisica sperimentale delle interazioni fondamentali e applicazioni
Particle decays; Particle interactions; Leptons; Quarks; Polarization; Hadron colliders
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/149546
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