Related papers: Constraining new interactions with leptonic tau de…
The tau neutrino is probably the least studied particle in the SM, with only a handful of interaction events being identified so far. This can in part be attributed to their small production rate in the SM, which occurs mainly through D_s…
We quantitatively discuss the possibility of deriving model-independent constraints on the general four-fermion contact interaction couplings, from the currently available data on the two-fermion production processes $e^+e^-\to\mu^+\mu^-$,…
In the L_{\mu} - L_{\tau} model the 3.6$\sigma$ discrepancy between the predicted and measured values of the anomalous magnetic moment of positive muons can be explained by the existence of a new dark boson Z' with a mass in the sub-GeV…
In this work we perform a non-linear extension of the $U(1)_{\rm Y}$ sector of the Standard Model leading to novel quartic effective interactions between the neutral gauge bosons. We study the induced effects through high-energy processes…
Using the general connection between the upper limit on the neutrino mass and the upper limits on certain types of non-Standard Model interaction that can generate loop corrections to the neutrino mass, we derive constraints on some…
We consider nonstandard interactions of neutrinos with electrons arising from a new light spin-1 particle with mass of tens of GeV or lower and couplings to the neutrinos and electron. This boson is not necessarily a gauge boson and is…
We review the physics of purely leptonic decays of $\pi^\pm$, $K^\pm$, $D^{\pm}$, $D_s^\pm$, and $B^\pm$ pseudoscalar mesons. The measured decay rates are related to the product of the relevant weak-interaction-based CKM matrix element of…
The Belle Collaboration has measured the complete set of angular coefficient functions for the decays ${\bar B} \to D^*\,(D\,\pi)\,\ell\,{\bar \nu}_{\ell}$, where $\ell = e,\,\mu$, in four bins of the variable $w={m_B^2+m_{D^*}^2-q^2 \over…
The most general form of the hamiltonian for the muon decay is presented. We assume that it arises as a result of the exchange of intermediate bosons with a momentum $q$ and naturally should depend on this momentum. That allows us to…
Leptophilic interactions can only be observed at the LHC in four-lepton final states. If these interactions are mediated by a resonance in the di-leptonic channel with renormalizable couplings, the mediator must have spin 1. We study the…
Contribution from new gauge bosons in the 3 - 3 - 1 models to the anomalous magnetic moment of the muon, mass difference of the kaon system and rare kaon decay are calculated and numerically estimated. Bounds on masses of new gauge bosons:…
In a truly model-independent approach, we reexamine a minimal extension of the Standard Model (SM) through the introduction of an additional $U(1)$ symmetry leading to a new neutral gauge boson ($Z'$), allowing its kinetic mixing with the…
Several models of dark matter motivate the concept of hidden sectors consisting of SU(3)_C x SU(2)_L x U(1)_Y singlet fields. The interaction between our and hidden matter could be transmitted by new abelian U'(1) gauge bosons A' mixing…
We present a comprehensive investigation on the possibility of the search for new force mediator $X$ boson in $e^+e^-$ collision and $J/\psi$ decay at the BESIII experiment. The typical interactions of $X$ boson coupling to leptons and…
The doubly charged scalar boson (H^{\pm\pm}) is introduced in several models of the new physics beyond the standard model. The H^{\pm\pm} has Yukawa interactions with two left-handed charged leptons or two right-handed charged leptons…
New interactions with Lorentz scalar structure, arising from physics beyond the standard model of electroweak interactions, will induce effective pseudoscalar interactions after renormalization by weak interaction loop corrections. Such…
We study the five-body decays $\mu^- \to e^- e^+ e^- \nu_{\mu} \bar{\nu}_{e}$ and $\tau^- \to \ell^- \ell'^+\ell'^-\nu_{\tau}\bar{\nu}_{\ell}$ for $\ell, \ell'=e, \mu$ within the Standard Model (SM) and in a general effective field theory…
A measurement of the polarization of W bosons in semi-leptonically decaying W pairs produced at 189 GeV is presented. Rates of longitudinally and transversely polarized W bosons and correlation between two W bosons are studied. The spin…
The exclusive (B -> K_2 l^+ l^-) decay is studied using the most general, model independent four-fermion interaction. The sensitivity of the ratio of the decay widths when K_2 meson is longitudinally and transversally polarized, the…
We constrain $C\!P$-violating charged and neutral anomalous triple gauge couplings using LHC measurements and projections of diboson and VBF $Vjj$ production, both with subsequent leptonic decays. For triple gauge couplings involving $W$…