Probes of New Physics in the Era of High Luminosity Flavor Experiments
Final Report Abstract
During the DFG Research Fellowship at Cornell, we worked on a broad set of topics enabling probes for physics that goes beyond our current understanding in the era of the high luminosity flavor experiments LHCb and Belle II, including charm, beauty, and kaon physics. The recent discovery of CP violation in charm decays makes charm physics a “hot topic” and opens up a whole new field, as we are now sensitive to the difference between matter and antimatter in regions we have not been before. We put forward one of the first theory interpretations of the new experimental results and showed how to move forward, by providing the methodology to solve the complete correlated U-spin system. We made further advances for the theory predictions of CP violation in charmed baryon and multibody decays, which is very important as LHCb gathers a huge amount of data on these decays. Likewise, in b-physics we performed a general comprehensive SU(3)F analysis of decays of beauty baryon antitriplets to a member of the light baryon octet and a singlet, in which we also discuss isospin breaking effects and Σ–Λ mixing. The observation of the isospin violating decay Λb → ΣJ/ψ may be around the corner at LHCb. From exclusive semileptonic B meson decays, we extracted the state-of-the-art value of Vcb , which is an important ingredient for the unitarity test of the Cabibbo-Kobayashi-Maskawa triangle. Furthermore, we provided the up to date Standard Model prediction of the observable R(D∗) which can by used to test lepton-flavor universality in b → cτ ν vs. b → clν decays. On top of that, we found a new universality relation for various hadronic decays, such as Bc → J/ψτ ν, Bc → ηc τ ν, and Bs → D(∗)s τ ν, that share the same underlying parton level transition, and that can be used to probe for operators with a different Lorentz structure than present in the Standard Model. In Kaon physics, we worked on the statistical methodology of Standard Model tests employing different measurements of the Cabibbo angle. Future precision tests and additional extractions of the Cabibbo angle from various decay channels can use our method for an improved search for New Physics. We know for very solid reasons that the Standard Model is not the end of the story and that New Physics must exist. The high luminosity flavor experiments and theoretical flavor physics will be key players for future discoveries. It will help us to explore the nature of the yet unknown, and to find answers to the big questions of particle physics.
Publications
- “The emergence of the ∆U = 0 rule in charm physics,” JHEP 1907, 020 (2019)
Y. Grossman and S. Schacht
(See online at https://doi.org/10.1007/JHEP07(2019)020) - “The Vcb puzzle: An update,” Phys. Lett. B 795, 386 (2019)
P. Gambino, M. Jung and S. Schacht
(See online at https://doi.org/10.1016/j.physletb.2019.06.039) - “Relations between b → cτν Decay Modes in Scalar Models”. JHEP
S. Schacht and A. Soni
(See online at https://doi.org/10.1007/JHEP10(2020)163) - “SU(3)F analysis for beauty baryon decays,” JHEP 2003, 165 (2020)
A. Dery, M. Ghosh, Y. Grossman and S. Schacht
(See online at https://doi.org/10.1007/JHEP03(2020)165)
