TY  - JOUR
AU  - Penalva, N.
AU  - Hernandez, E.
AU  - Nieves, J.
PY  - 2021
DA  - 2021//
TI  - New physics and the tau polarization vector in b -> c tau barnutau decays
T2  - J. High Energy Phys.
JO  - Journal of High Energy Physics
SP  - 118
EP  - 37pp
VL  - 06
IS  - 6
PB  - Springer
KW  - Beyond Standard Model
KW  - CP violation
AB  - For a general H-b -> Hc tau nu <overbar></mml:mover>tau decay we analyze the role of the tau polarization vector P μin the context of lepton flavor universality violation studies. We use a general phenomenological approach that includes, in addition to the Standard Model (SM) contribution, vector, axial, scalar, pseudoscalar and tensor new physics (NP) terms which strength is governed by, complex in general, Wilson coefficients. We show that both in the laboratory frame, where the initial hadron is at rest, and in the center of mass of the two final leptons, a P -></mml:mover> component perpendicular to the plane defined by the three-momenta of the final hadron and the tau lepton is only possible for complex Wilson coefficients, being a clear signal for physics beyond the SM as well as time reversal (or CP-symmetry) violation. We make specific evaluations of the different polarization vector components for the Lambda (b) -> Lambda (c), <mml:mover accent="true">B<mml:mo stretchy="true"><overbar></mml:mover>c -> eta (c), J/psi and <mml:mover accent="true">B<mml:mo stretchy="true"><overbar></mml:mover> -> D-(*) semileptonic decays, and describe NP effects in the complete two-dimensional space associated with the independent kinematic variables on which the polarization vector depends. We find that the detailed study of P μhas great potential to discriminate between different NP scenarios for 0(-) -> 0(-) decays, but also for Lambda (b) -> Lambda (c) transitions. For this latter reaction, we pay special attention to corrections to the SM predictions derived from complex Wilson coefficients contributions.
SN  - 1029-8479
UR  - https://arxiv.org/abs/2103.01857
UR  - https://doi.org/10.1007/JHEP06(2021)118
DO  - 10.1007/JHEP06(2021)118
LA  - English
N1  - WOS:000664505100002
ID  - Penalva_etal2021
ER  -