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Impact of polarization observables and Bc→τν on new physics explanations of the b→cτν anomaly.
- Source :
-
Physical Review D: Particles, Fields, Gravitation & Cosmology . Apr2019, Vol. 99 Issue 7, p1-1. 1p. - Publication Year :
- 2019
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Abstract
- The combined analysis of the BABAR, Belle, and LHCb data on B→Dτν, B→D∗τν and Bc→J/Ψτν decay observables shows evidence of physics beyond the Standard Model (SM). In this article, we study all the one- and two-dimensional scenarios which can be generated by adding a single new particle to the SM. We put special emphasis on the model-discriminating power of FL(D) and of the τ polarizations, and especially on the constraint from the branching fraction BR(Bc→τν). We critically review this constraint and do not support the aggressive limit of BR(Bc→τν)<10% used in some analyses. While the impact of FL(D∗) is currently still limited, the BR(Bc→τν) constraint has a significant impact: depending on whether one uses a limit of 60%, 30% or 10%, the pull for new physics (NP) in scalar operators changes drastically. More specifically, for a conservative 60% limit a scenario with scalar operators gives the best fit to data, while for an aggressive 10% limit this scenario is strongly disfavored and the best fit is obtained in a scenario in which only a left-handed vector operator is generated. We find a sum rule for the branching ratios of B→Dτν, B→D∗τν and Λb→Λcτν which holds for any NP contribution to the Wilson coefficients. This sum rule entails an enhancement of BR(Λb→Λcτν) over its SM prediction by (24±6)% for the current R(D(*)) data. [ABSTRACT FROM AUTHOR]
- Subjects :
- *BRANCHING ratios
*PHYSICS
*EXPLANATION
Subjects
Details
- Language :
- English
- ISSN :
- 24700010
- Volume :
- 99
- Issue :
- 7
- Database :
- Academic Search Index
- Journal :
- Physical Review D: Particles, Fields, Gravitation & Cosmology
- Publication Type :
- Periodical
- Accession number :
- 136358024
- Full Text :
- https://doi.org/10.1103/PhysRevD.99.075006