Related papers: New physics facing LFU and LFV tests in B physics
The anomalies in the $B$-meson sector, in particular $R_{K^{(*)}}$ and $R_{D^{(*)}}$, are often interpreted as hints for physics beyond the Standard Model. To this end, leptoquarks or a heavy $Z'$ represent the most popular SM extensions…
The RK measurement by LHCb suggests non-standard lepton-universality violation (LUV) to occur in b to s l+ l- decays, with effects in muons rather than electrons. It is intriguing that a number of other measurements of b to s l+ l-…
The LHCb experiment at the Large Hadron Collider specialises in high-precision measurements of flavour physics with hadrons containing $b$ and $c$ quarks. Lepton flavour universality tests provide an accurate and clear approach to…
The search for lepton flavour violation in charged lepton decays is highly sensitive to physics beyond the Standard Model. Among the possible processes, $\mu$-decays are considered to have the largest discovery potential in most of the…
Quark and lepton flavor signals are studied in four supersymmetric models, namely the minimal supergravity model, the minimal supersymmetric standard model with right-handed neutrinos, SU(5) supersymmetric grand unified theory with…
We examine various scenarios that involve a light ${\cal O}(1 TeV)$ leptoquark state and select those which are compatible with the current experimental values for $\mathcal{B}(B_s\to \mu\mu)$, $\mathcal{B}(B\to…
Deviation from the standard model prediction is observed in many semileptonic $B$ decays mediated via $b \to c$ charged current interactions. In particular, current experimental measurements of the ratio of branching ratio $R_D$ and…
We address the $B$-physics anomalies within a two scalar leptoquark model. The low-energy flavor structure of our set-up originates from two $SU(5)$ operators that relate Yukawa couplings of the two leptoquarks. The proposed scenario has a…
At present, there are several hints of lepton flavor non-universality. The LHCb Collaboration has measured $R_K\equiv{\cal B}(B^+ \to K^+ \mu^+ \mu^-)/{\cal B}(B^+ \to K^+ e^+ e^-)$, and the BaBar Collaboration has measured $R(D^{(*)})…
Lepton universality, meaning the equal coupling of the electroweak gauge bosons to the different lepton flavours, is a central property of the Standard Model (SM). Tests of lepton universality in ratios of rates of $b\to s\ell^+\ell^-$…
Lepton Flavor Violating (LFV) processes are clear signals of physics beyond the Standard Model. We investigate the possibility of measuring this kind of processes at present and foreseeable future muon-electron colliders, taking into…
We argue that radiative lepton flavor violating (RLFV) decays $P \to \gamma \ell_1 \overline{\ell}_2$ of $P =B^0_q$, $\bar{D}^0$, and $K^0$ meson states are robust probes of new physics models. In particular, they could be used to put…
One of the key assumptions of the Standard Model of fundamental particles is that the interactions of the charged leptons, namely electrons, muons, and taus, differ only because of their different masses. While precision tests comparing…
Measurements of the ratio of $B \to K^* \mu \mu $ to $B \to K^* e e $ branching fractions, $R_{K^*}$, by the LHCb collaboration strengthen the hints from previous studies with pseudoscalar kaons, $R_K$, for the breakdown of lepton…
We study (semi)leptonic rare charm decays and its opportunities in searches for physics beyond the Standard Model (BSM). In particular, we analyse the impact of potential BSM physics in $c\to ull'$ transitions, notably branching ratios,…
We review the current status and implications of the anomalies (i.e. deviations from the Standard Model predictions) in semi-leptonic $B$ meson decays, both in the charged and in the neutral current. In $b\to s\ell^+\ell^-$ transitions…
This report introduces two recent measurements of semileptonic $b$-hadron decays at the LHCb experiment, including a test of Lepton Flavour Universality (LFU) using $\bar{B}^0 \to D^{(*)+} l^- \bar{\nu}_l$ decays where $l\in\{\mu,\tau\}$,…
Motivated by the recent measurement of the lepton flavour nonuniversality ratio $R_{K^*}$ by the LHCb Collaboration, we study the implications of vector leptoquarks on the observed anomalies associated with the $\bar B \to \bar K^* l^+ l^-$…
I review the recent theoretical progress on the study of tree-level semileptonic $b\to c$ decays. After briefly reviewing the latest developments on the exclusive determinations of $|V_{cb}|$, I discuss the hints on lepton flavor…
In the coming years, experiments underway will increase the sensitivity to charged lepton flavor violation by four orders of magnitude. These experiments will stringently probe weak scale physics. I review the status of global symmetries in…