Related papers: Four-fermion operators, $Z$-boson exchange, and $\…
While electron and muon dipole moments are well-established precision probes of physics beyond the standard model, it is notoriously challenging to test realistic new-physics (NP) scenarios for the $\tau$ lepton. Constructing suitable…
If physics beyond the Standard Model (BSM) explains the $4.2\sigma$ difference between the Standard-Model and measured muon anomalous magnetic moment, $a_{\mu}$, minimal flavor violation predicts a shift in the analog quantity for the…
We investigate the effects of possible new four-Fermi operators on $e^+$ $e^-$ annihilation experiments. They represent a class of new physics, which has the potential to change the parameters of the $Z$ boson and at the same time…
The recently completed calculation of the full electroweak O(alpha) corrections to the charged-current four-fermion production processes e+e- --> nu_tau tau+ mu- anti-nu_mu, u anti-d mu- anti-nu_mu, and u anti-d s anti-c is briefly…
We present a comprehensive investigation into the anomalous magnetic dipole moment ($a_\tau$) and electric dipole moment ($d_\tau$) of the $\tau$ lepton using the $\gamma\gamma \to \tau^+\tau^-$ process at future lepton colliders, with the…
The calculation of the full electroweak O(alpha) corrections to the charged-current four-fermion production processes e+e- --> nu_tau tau+ mu- anti-nu_mu, u anti-d mu- anti-nu_mu, and u anti-d s anti-c is briefly reviewed. The calculation…
Anomalous contributions to the electric and magnetic dipole moments of the $\tau$ lepton from new physics scenarios have brought renewed interest in the development of new charge-parity violating signatures in $\tau$-pair production at…
An analysis of electroweak corrections to the anomalous dipole moments of lepton from some special two-loop diagrams where a closed neutralino/chargino loop is inserted into relevant one-loop diagrams of the standard model is presented in…
We study the constraints that can be placed on anomalous $\tau$-lepton couplings at the LHC. We use an effective Lagrangian description for physics beyond the standard model which contains the $\tau$-lepton anomalous magnetic moment,…
In the Standard Model Effective Field Theory (SMEFT), operators involving the top quark are generally difficult to probe, and can generate sizable loop contributions to the electroweak precision observables, measured by past and future…
Precise measurement of the Electric Dipole Moment (EDM) and anomalous magnetic moment ($g$-2) of particles are important tests of Beyond Standard Model (BSM) physics. It is generally believed that the tau lepton couples more strongly to BSM…
We report a measurement of the electric dipole moment of the $\tau$ lepton ($d_\tau$) using an 833~fb$^{-1}$ data sample collected near the $\Upsilon(4S)$ resonance, with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider.…
We discuss new-physics searches and symmetry tests with dipole moments, emphasizing the role of polarization observables. As a primary benchmark, we consider polarized photon fusion in the $e^+ e^-$ environment of the Super Tau-Charm…
Electroweak processes with four fermions in the final state were measured extensively at LEP-2 in e+e- collisions with centre-of-mass energies up to 209 GeV. By combining the results obtained by Aleph, Delphi, L3 and Opal, the predictions…
A calculation of weak dipole moments of charged fermions of the Standard Model (SM) at the one-loop level, in the context of a general effective extended neutral current model with flavor changing $Z^\prime f_i \bar{f}_j$ vertices, is…
The anomalous magnetic ($\tilde{a}_\tau$) and electric dipole ($\tilde{d}_\tau$) moment of tau lepton described in $\tau\bar{\tau}\gamma$ vertices are studied via $\mu^{+}\mu^{-} \rightarrow \tau^+\bar{\tau}^-$ process at the Muon colliders…
Four-fermion operators may have large anomalous scaling and become relevant operators in some strongly interacting gauge theories. We present a detailed model which illustrates some of the implications of such operators for the generation…
The chirality-flipping operators of light fermions are currently poorly constrained by experimental analyses due to the lack of interference with Standard Model (SM) amplitudes in traditional observables. In this work, we propose to…
We perform a model-independent analysis of the magnetic and electric dipole moments of the muon and electron. We give expressions for the dipole moments in terms of operator coefficients of the low-energy effective field theory (LEFT) and…
We study gravity with torsion in extra dimensions and derive an effective four-dimensional theory containing four-fermion contact operators at the fundamental scale of quantum gravity in the TeV range. These operators may have an impact on…