Related papers: A Challenge to Lepton Universality in B Meson Deca…

Model independent tests for symmetry violations in tau decays are important for determining whether the tau lepton is elementary or, instead, macroscopic. Such tests are also significant steps towards resolving the outstanding "e - mu -…

The pure lepton decay of the polarized muon is considered, accounting for a new tensor interaction which is outside of the Michel local interactions. This interaction leads to new energy distribution and polarization of the final charged…

Since its discovery in the 1930s, the muon has played an important role in our quest to understand the sub-atomic theory of matter. The muon was the first second-generation standard-model particle to be discovered, and its decay has…

Two topics have recently risen to prominence within the ongoing searches of beyond-Standard Model effects in $b$ and $c$ decays: observables that test lepton flavor universality (LFU) as well as lepton flavor violation (LFV). A coherent set…

The ratio of branching fractions of the decays $\Lambda^{0}_{b}\to pK^{-}e^{+}e^{-}$ and $\Lambda^{0}_{b}\to pK^{-}\mu^{+}\mu^{-}$, $R^{-1}_{pK}$, is measured for the first time using proton-proton collision data corresponding to an…

Motivated by the measurements of $b\to s\ell^+\ell^-$ transitions, including $R(K)$ and $R(K^*)$, we examine lepton flavour (universality) violation in $B$ decays and its connections to $\mu\to e\gamma$ in generic leptoquark models.…

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…

The Standard Model of Particle Physics has proven to be tremendously successful as the fundamental theory that describes the elementary particles that compose our Universe, as well as the interactions among them. Despite the countless…

These proceedings review the status of New Physics contributions to flavour violating $B$ decays. The anomalies in charged and neutral current $B$ decays related to lepton flavour universality violation have received a substantial amount of…

Decays of B mesons to states involving tau leptons can be used as a tool to search for the effects of new physics, such as those involving a charged Higgs boson. The experimental status of the decays B -> tau nu and B -> D^(*) tau nu is…

The observation of neutrino oscillation as well as the recent experimental result on lepton flavor universality (LFU) violation in $B$ meson decays are indications of new physics beyond the Standard Model. Many theoretical models, which are…

$\tau$ is playing an important role in the current B-physics indications from experiments of lepton flavor universality violations(LFUV). This suggests it be given increasing attention theoretically in the coming years, given also the fact…

This Thesis presents my personal contributions to two distinct fields, namely the recent experimental anomalies in B-meson decays, and the longstanding quest for a theoretical explanation of lepton masses and mixings, under a unifying…

Leptoquarks are ubiquitous in several extensions of the Standard Model and seem to be able to accommodate the universality-violation-driven $B$-meson-decay anomalies and the $(g-2)_\mu$ discrepancy interpreted as deviations from the…

Present measurements of b->c tau nu and b->u tau nu transitions differ from the standard model predictions of lepton flavor universality by almost 4sigma. We examine new physics interpretations of this anomaly. An effective field theory…

Using a sample of 122 million Upsilon(3S) decays collected with the BaBar detector at the PEP-II asymmetric energy collider at the SLAC National Accelerator Laboratory, we measure the ratio…

We present a measurement of the ratio $R_\mu = \mathcal{B}(\tau^-\to \mu^-\bar\nu_\mu\nu_\tau) / \mathcal{B}(\tau^-\to e^-\bar\nu_e\nu_\tau)$ of branching fractions $\mathcal{B}$ of the $\tau$ lepton decaying to muons or electrons using…

We present the first comprehensive tests of light-lepton universality in the angular distributions of semileptonic $B^0$-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay…

The study of muon properties and decays played a crucial role in the early years of particle physics and contributed over decades to build and consolidate the Standard Model. At present, searches for muon decays beyond the Standard Model…

It has been recently proposed that neutrino mass could originate from Yukawa interactions of leptons with new colored particles. This raises the interesting possibility of testing mass generation through copious production of those…