Related papers: Tau as a Probe for New Physics
We study two and three meson decays of the tau lepton within the framework of the Resonance Chiral Theory, that is based on the following properties of QCD: its chiral symmetry in the massless case, its large-N_C limit, and the asymptotic…
We have investigated the electromagnetic moments of the tau lepton in $e^{+}e^{-} \rightarrow e^{+}\gamma^{*} \gamma^{*} e^{-}\rightarrow e^{+}\tau \bar{\tau}e^{-}$ process at the CLIC. We have obtained 95% confidence level bounds on the…
The spin correlations in the pair of $\tau$ leptons produced in the high-energy proton-proton collisions are studied. The invariant mass of the $\tau$-lepton pair is chosen close to $Z$-boson mass, in these conditions $Z$-boson exchange…
Exclusive semi-leptonic decays of the tau lepton offer a clean probe to study the hadronization of QCD currents in its non-perturbative regime and learn about resonance dynamics, which drives strong interactions in these processes. In this…
Testing New-Physics (NP) scenarios that couple predominantly to the third generation is notoriously difficult experimentally, as exemplified by comparing limits for the $\tau$ lepton dipole moments to those of electrons and muons. In this…
Precise measurements of the lepton properties provide stringent tests of the Standard Model structure and accurate determinations of its parameters. We overview the present status of a few selected topics: lepton universality, QCD tests and…
The tau is the only known lepton that can decay hadronically. From this class of decays, high precision measurements of several quantities can be extracted: the CKM matrix element $V_{us}$, the mass of the strange quark, etc. Also, as a…
The polarizability measures how the system responds to an applied electrical field. Computationally, there are many different ways to evaluate this tensorial quantity, some of which rely on the explicit use of the external perturbation and…
The $\tau$ lepton arising from the scalar tau ($\st$) decay is naturally polarized. $\ptau$ depends on the left--right mixing of the $\st$ and the gaugino--higgsino mixing of the neutralino. The polarization $\ptau$ could be measured from…
We revisit the status of the new-physics interpretations of the anomalies in semileptonic $B$ decays in light of the new data reported by Belle on the lepton-universality ratios $R_{D^{(*)}}$ using the semileptonic tag and on the…
Low energy tau pair production, at B factories and on top of the $\Upsilon$ resonances, allows for a detailed investigation on the CP violation at the electromagnetic tau pair production vertex. High statistic available at low energies…
We study the longitudinal polarization of the tau lepton in B -> D tau nu decay. After discussing possible sensitivities of tau decay modes to the tau polarization, we examine the effect of charged Higgs boson on the tau polarization in B…
The proposed high-luminosity B/Flavor factories offer new opportunities for the improved determination of the fundamental physical parameters of standard heavy leptons. Compared to the electron or the muon case, the magnetic properties of…
We study the four-top final state at the LHC as a probe for New Physics (NP) effects due to new particles that couple predominantly to the top quark and whose masses are below the top-quark-pair production threshold. We consider simple NP…
Compton scattering results are used to probe proton structure via measurement of higher order polarizabilities. Values for $\alpha_{E2}^p,\beta_{E2}^p,\alpha_{E\nu}^p,$ $\beta_{E\nu}^p$ determined via dispersion relations are compared to…
Spin polarizabilities provide information on the internal structure of hadrons in the presence of weak external electromagnetic fields, and are actively studied by Compton scattering experiments. They provide finer detail than the regular…
A review of Lorentz and CPT tests performed in atomic systems is presented. A theoretical framework extending QED in the context of the standard model is used to analyze a variety of systems. Experimental signatures of possible Lorentz and…
We revisit the constraints on semileptonic operators derived from the mono-$\tau$ high-$p_T$ events in $pp$ collisions at LHC. Like in previous studies, we obtain limits on the New Physics couplings from the CMS data much stronger than from…
Charge-parity ($C\!P$) violation in the tau-charm energy region is a promising area for sensitive tests of Standard Model (SM) predictions and searches for new, beyond the SM physics. A future Tau-Charm Facility that operates at…
Searches for permanent electric dipole moments of fundamental particles and systems with spin are the experiments most sensitive to new CP violating physics and a top priority of a growing international community. We briefly review the…