“A new B-flavour anomaly in Bd,s->K0 anti-K0: anatomy and interpretation” by M. Algueró, A. Crivellin, S. Descotes-Genon, J. Matias and M. Novoa-Brunet. has been submitted to the arXiv.
We identify a new anomaly in an observable that we called L, constructed upon the longitudinal amplitudes of the non-leptonic decays Bd->K0* anti K0* versus Bs->K0* anti K0*. This observable is protected from leading order infrared divergences in hard-scattering and weak annihilation diagrams and exihibits a 2.6 sigma tension with data.
We establish a parallelism with RK of semileptonic B decays interchanging leptons by quarks and we identify the dominant Wilson coefficient in an EFT approach that could explain the anomaly with a 25% NP contribution.
In the Media
Latest Fermilab reuslts at diari ARA
April 9, 2021
Pere Masjuan is quoted in an article in the diari Ara about the lastest Fermilab’s Muon g-2 experiment results.
New experimental results
LHCb results strengthen hints of a violation of lepton flavour universality
April 7, 2021
LHCb has overcome the 3 sigma barrier in the tension between the measurement of the observable RK and the prediction of the SM, reaching 3.1 sigmas. This observable tests the universality (or not) of leptonic flavor. The SM predicts a value of 1 very accurately for this observable.