Abstract
There is growing evidence for deviation from the standard model predictions in the ratios between semi-tauonic and semi-leptonic $B$ decays, known as the $R(D^{(*)})$ puzzle. If the source of this non-universality is new physics, it is natural to assume that it also breaks CP symmetry. In this paper we study the possibility of measuring CP violation in semi-tauonic $B$ decays, exploiting interference between excited charm mesons. Given the current values of $R(D^{(*)})$, we find that our proposed CP-violation observable could be as large as about 10%. We discuss the experimental advantages of our method and propose carrying it out at Belle II and LHCb.
Highlights
Within the standard model (SM) of particle physics, the electroweak (EW) interactions obey flavor symmetry and exhibit lepton flavor universality (LFU)
In this paper we suggest a new method to study CP violation in B → DÃÃð→ DðÃÞπÞτ−ντ decays
Our motivation is based on the so-called RðDðÃÞÞ anomaly of lepton flavor nonuniversality in B → DðÃÞτ−ντ decays
Summary
Within the standard model (SM) of particle physics, the electroweak (EW) interactions obey flavor symmetry and exhibit lepton flavor universality (LFU). More recent calculations of RðDÃÞ [14,15,16] reduce this tension somewhat, but do not solve the puzzle Another b → cτνratio was recently measured by LHCb [17], RðJ=ψ. The object of this paper is to introduce and explore a new observable that incorporates strong phases, and is sensitive to CP violation in models that break lepton universality in b → cτν transitions. We discuss an alternative that is applicable for both leptonic and semihadronic τ− decays It does not require measurement of angular variables, does benefit from even partial angular information that is experimentally obtainable.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
