A selection of recent results from the Belle II and LHCb experiments are presented.
Non-leptonic B decays are great probes of CP violation and the most precise probes for the CKM angles. These determinations use golden modes, data and/or isospin symmetry to reduce the theoretical uncertainties, as non-leptonic decays remain notoriously challenging to calculate from QCD principles. At the same time, there is a wealth of experimental data that can be exploited to obtain...
We consider various modes based on $c\to s e \nu$ in order to see what precision of LQCD results for relevant hadronic matrix elements and of the experimental data are needed to probe the effects of physics beyond the SM.
$c\to s e \nu$ case is good for many reasons, including the fact that all of its couplings to physics BSM are strongly constrained by the measured high-pT tails of the...
The non-observation of baryon number violation suggests that the scale of baryon-number violating interactions at zero temperature is comparable to the GUT scale. However, the pertinent measurements involve hadrons made of the first-generation quarks, such as protons and neutrons. One may entertain the idea that new flavor physics breaks baryon number at a much lower scale, but only in the...
In this talk, we discuss inclusive decays of heavy hadrons containing a b-quark, specifically focusing on Lambda-b baryons within the framework of the heavy quark expansion (HQE). By utilising recent lattice QCD calculations of exclusive form factors, we aim to identify the regions in the plane of non-perturbative parameters—namely the kinetic and Darwin terms—that are consistent with small...
The theoretical predictions for the $D-\bar{D}$ mixing parameters fall significantly short of experimental measurements, with discrepancies spanning several orders of magnitude. This divergence is largely attributed to the Glashow–Iliopoulos–Maiani (GIM) mechanism, which suppresses leading-order contributions. However, higher-order corrections and nonperturbative effects have the potential to...
In this talk, I will review the bounds that can be inferred on New Physics couplings to heavy sterile neutrinos $N$ from the recent measurements performed by the Belle collaboration of the angular analysis of $B \to D^*\ell\nu$ decays, with $\ell=e,\mu$. Indeed, a sterile neutrino N may lead to competing $B \to D^*\ell N$ decays and Belle might have measured an incoherent sum of these two...
For several years, many long-standing anomalies in rare $b \to s\ell \bar\ell$ decays have raised questions about possible hints of physics beyond the Standard Model (SM). These anomalies appear not only in branching ratios of $B\to K$, $B\to K^*$, and $B_s\to \phi$ in both high- and low-$q^2$ regions (with $q^2$ the invariant mass of the dilepton pair), but also in angular observables such as...
Any study of leptoquark (LQ) searches at colliders must include constraints on the parameter space from low-energy physics. I show that radiative corrections to the leptoquark-fermion couplings can be large and have a particularly simple pattern: If only one LQ species is present, the radiative corrections are universal and deplete all LQ-fermion couplings probed at high energies (in on-shell...
We derive a generalisation of the Boyd-Grinstein-Lebed (BGL) parametrization. Most form factors (FFs) in $b$-hadron decays exhibit additional branch cuts --- namely subthreshold and anomalous branch cuts --- beyond the "standard'' unitarity cut. These additional cuts cannot be adequately accounted for by the BGL parametrization. For instance, these cuts arise in the FFs for $B\to D^{(*)}$,...
The fact that the quark and charged-lepton mass spectrum is hierarchical remains a tantalising hint that beyond-SM physics might be at play. I will review work I completed with Baker and Cox on a systematic analysis of 1-loop generation of the bottom and tau masses, which are, of course, known to be suppressed compared to the fundamental electroweak scale. Note that both of those species have...
