相关论文: A Model of Universality Violation Revisited
The Standard Model of particle physics currently provides our best description of fundamental particles and their interactions. The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak…
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…
We explore the unitarity violation of the CKM matrix in the model in which the third generation fermions are subjected to the separate SU(2)$_L$ gauge interaction. With the recent LEP and SLC data at $Z$-pole and low-energy neutral current…
The number of leptons may or may not be a conserved quantity. The Standard Model predicts that it is (in perturbative processes), but there is the well known possibility that new physics violates lepton number in one or two units. The first…
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 have not…
The most severe constraints on quark-lepton four-fermion contact interactions come from the agreement of atomic parity violation measurements with the Standard Model. In this letter I note that for contact interactions which arise in…
Motivated by recent experimental measurements on flavour physics, in tension with Standard Model predictions, we perform an updated analysis of New Physics violating Lepton Flavour Universality, by using the effective Lagrangian approach…
The possibility of additional quarks and leptons beyond the three generations already established is discussed. The make-up of this Report is (I) Introduction: the motivations for believing that the present litany of elementary fermions is…
We study a model with partial quark-lepton universality that can naturally arise in grand unified theories. We find that constraints on the model can be reduced to a single condition on the Dirac CP phase $\delta$ in the neutrino sector.…
In this talk I will present the work that we did in \cite{1}\cite{2}\cite{3}\cite{4}\cite{5} related to observed lepton universality violation by Babar, Belle and LHCb in R($D^{(*)}$) and $R_{K^{(*)}}$ as well as the reported deviation in…
An important prediction of the standard model is the universality of the gauge interactions of the three generation of charged leptons. Violation of this universality would be a clean evidence of new physics (NP) beyond the standard model.…
In this addendum to arXiv:2101.07811 we discuss the implications of the recent CMS analysis of lepton flavour universality violation in non-resonant di-lepton pairs for first generation leptoquarks. As CMS finds more electron events than…
Lepton number violation and its relation to neutrino masses is investigated in several versions of the $SU(3)_c\otimes SU(3)_L\otimes U(1)_x$ model. Spontaneous and explicit violation and conservation of the lepton number are considered. In…
We calculate a number of observables related to particle-antiparticle mixing and the branching ratios for the most interesting rare and CP-violating K and B decays in the Standard Model (SM3) extended by a fourth generation of quarks and…
In the Standard Model extended by sterile neutrinos, modified W-l-nu couplings arise, which are able to induce a tree-level enhancement to lepton flavour universality violation in kaon decays. The additional mixing between the active…
We present a short overview of recent work on the topic of flavour violation in the presence of a sequential fourth generation (4G) of quarks and leptons. We discuss the implications of this simple extension of the Standard Model (SM3) for…
In the absence of a fundamental principle preventing charged lepton flavour violation, one expects that extensions of the Standard Model accommodating neutrino masses and mixings should also allow for charged lepton flavour violating…
The phase convention independent measure of CP violation for three generations of leptons is evaluated at different energy scales. Unlike in the quark sector, this quantity does not vary much between the weak and the grand unification…
Leptoquarks are prime candidates for explaining the intriguing hints for lepton flavour universality violation. In particular, the $SU(2)_L$ doublet of scalar leptoquarks $S_2$ is capable of providing an explanation for the tensions between…
We interpret anomalies, deviations, from the standard model as being in fact due to effects not given by perturbation, because the top Yukawa coupling is after all so large that not by perturbation effects become important. Most of the…