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

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 integrat...

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Bibliographic Details
Authors: Calvo Gomez, Miriam, Golobardes Ribé, Elisabet, Vilasis-Cardona, Xavier, LHCb Collaboration - CERN
Format: article
Publication Date:2023
Country:España
Institution:Universitat Ramon Llull (URL)
Repository:DAU Arxiu Digital de la Universitat Ramon Llull
OAI Identifier:oai:dau.url.edu:20.500.14342/6041
Online Access:http://hdl.handle.net/20.500.14342/6041
https://doi.org/10.1103/PhysRevD.110.092007
Access Level:Open access
Keyword:Particle decays
Particle interactions
Leptons
Quarks
Polarization
Hadron colliders
Gran col·lisionador d'hadrons (França i Suïssa)
530.1
539
Description
Summary: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.