Related papers: Tree-level new physics in $R(K^{(*)})$
Rare decays mediated by $b \to s \nu \bar \nu$ transitions have been reported by the Belle II experiment. The branching ratio of the decay $B^+ \to K^+ \nu \bar \nu$ is found to be enhanced with respect to the standard model value. If taken…
Tree-level Flavor-Changing Neutral Currents (FCNC) are characteristic of models with extra vector-like quarks. These new couplings can strongly modify the B^0 CP asymmetries without conflicting with low--energy constraints. In the light of…
We describe the form factors for B to rho lepton neutrino and B to K* gamma decays with just two parameters and the two form factors for B to pi lepton neutrino with a further two or three parameters. The parametrizations are consistent…
We critically analyze the body of results that hints to the existence of New Physics from possible violations of lepton universality observed by the LHCb experiment in the $\mu/e$ ratios $R_{K}$ and $R_{K^*}$ to the $g-2$ lepton anomalies.…
Updated standard model predictions for $D_{(s)} \to P l^+ l^-$, $l=e,\mu$, $P=\pi,K$ and inclusive decays are presented. Model-independent constraints on $|\Delta C|=|\Delta U|=1$ Wilson coefficients are worked out. New physics (NP)…
We study the left-right asymmetric model based on SU(3)_C \otimes SU(2)_L \otimes SU(3)_R \otimes U(1)_X gauge group, which improves the theoretical and phenomenological aspects of the known left-right symmetric model. This new gauge…
A model-independent analysis for the exclusive, rare B -> pi^+ pi^- l^+ l^- decay is presented. The dependence of the various physically measurable asymmetries and CP violating asymmetry on the new Wilson coefficients is studied in detail.…
The apparent absence of new heavy states at the LHC below the TeV scale points that there is a gap in the electroweak energy spectrum. This scenario is conveniently described through the electroweak effective theory, an effective…
The introduction of mirror fermions with masses between the weak scale and 1 TeV could offer a dynamical origin to the standard-model electro-weak symmetry breaking mechanism. The purpose of this work is to study the dynamics needed in…
Naturalness demands that the quadratic divergence of the one-loop top contribution to the Higgs mass be cancelled at a scale below 1 TeV. This can be achieved by introducing a fermionic (spin-1/2) top partner, as in, for example, Little…
Employing the SU(2) isospin symmetry of strong interactions and estimates borrowed from effective field theory, we explore the impact of new physics on the decays $B^\pm\to \phi K^\pm$ and $B_d\to \phi K_S$ in a model-independent manner. To…
We present HPQCD's improved scalar, vector and tensor form factors for $B \to K$ semileptonic decays, using the heavy-HISQ formalism for more accurate normalisation of the weak currents. Working with masses close to the physical $b$ on the…
We propose a scheme where the three relevant physics scales related to the supersymmetry, electroweak, and baryon minus lepton (B-L) breakings are linked together and occur at the TeV scale. The phenomenological implications in the Higgs…
We study extensions of the Standard Model where the charged current weak interactions are governed by the CKM matrix and where all tree-level decays are dominated by their Standard Model contribution. We constrain both analytically and…
Electroweak interactions need three Nambu-Goldstone bosons to provide a mass to the W and the Z gauge bosons but they also need an ultra-violet moderator or new physics to unitarize the gauge boson scattering amplitudes. In this talk, I…
We scrutinize the recently further strengthened hints for new physics in semileptonic $B$-meson decays, focusing on the 'clean' ratios of branching fractions $R_K$ and $R_{K^\ast}$ and examining to which pattern of new effects they point…
Motivated by the $\sim 2\sigma$ discrepancy between the experimental value for $R_b$ and the theoretical prediction of the Standard Model, we examine the effect of new physics on the $Z$-$b$-$\overline{b}$ vertex. Using general results for…
The recent measurements on $R_D$, $R_{D^*}$ and $R_{J/\psi}$ by three pioneering experiments, BaBar, Belle and LHCb, indicate that the notion of lepton flavour universality is violated in the weak charged-current processes, mediated through…
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…
Based on the low-energy effective Hamiltonian with the generalized factorization, we calculate the new physics contributions to branching ratios and CP-violating asymmetries of the charmless hadronic decays $B_s \to h_1 h_2$ in the standard…