Related papers: Precision Tests in e+e- and gamma-gamma processes …
The diphoton channel at lepton colliders, $e^+e^- (\mu^+\mu^-) \to \gamma \gamma$, has a remarkable feature that the leading new physics contribution comes only from dimension-eight operators. This contribution is subject to a set of…
We systematically study potential effects of Beyond the Standard Model physics in the $e^+ e^- \rightarrow Z H$ process. To this end, we include all relevant dimension-6 Standard Model Effective Field Theory operators and work to…
We show that the $m_W$ measurement is a direct probe of New Physics (NP) contributing to lepton and missing transverse momentum ($\ell+MET$), independently from indirect tests via the electroweak fit. Such NP modifies the kinematic…
We explore the indirect sensitivities to decoupled new physics of prospective precision electroweak measurements, triple-gauge-coupling measurements and Higgs physics at future $e^+e^-$ colliders, with emphasis on the ILC250 and FCC-ee. The…
Lepton flavor violation is one of the cleanest probes of physics beyond the standard model. In this work, we explore the sensitivity of the process $e^+ e^- \to \tau \mu$ to new physics above the TeV scale at the proposed circular…
New-physics (NP) constraints on first-generation quark-lepton interactions are particularly interesting given the large number of complementary processes and observables that have been measured. Recently, first hints for such NP effects…
We consider the possibility of fingerprinting the presence of heavy additional Z' bosons that arise naturally in extensions of the standard model such as E_6 models and left-right symmetric models, through their mixing with the standard…
We present a brief overview of the recent theoretical progress to describe the K_{l2} and K_{l3} decays. We discuss the interesting probes of the Standard Model offered by these decays such as the extraction of |V_{us}| and the test of the…
A search is presented for physics beyond the standard model (SM) using electron or muon pairs with high invariant mass. A data set of proton-proton collisions collected by the CMS experiment at the LHC at $\sqrt{s} =$ 13 TeV from 2016 to…
We present numerical results on the recently completed $O(\alpha^2)$ initial state corrections to the process $e^+e^- \rightarrow \gamma^*/Z^*$, which is a central process at past and future high energy and high luminsoity colliders for…
The amplitude of a Compton-like process nu_i gamma^* -> nu_j gamma^* with virtual photons is calculated in the standard GWS theory with lepton mixing. The contribution of this process to the high energy neutrino scattering on the nucleus…
The electron and muon magnetic moments have played, and continue to play, important roles in testing the fundamental mathematical description of physical reality called the Standard Model of particle physics (SM). The electron magnetic…
Data from the Large Electron Positron collider (LEP) at CERN on hadron production in gamma-gamma interactions exceed the predictions of the standard model by an order of magnitude at the highest observed transverse momenta in three…
Results from heavy flavour electroweak physics at LEP1 are reviewed together with measurements of 2-fermion processes at LEP2. For the former measurements the emphasis is on analyses of heavy quark forward-backward asymmetries, A_FB^b,c,…
We investigate the sensitivity of future linear collider experiments to CP violating $WW\gamma$ couplings in the process $e^{+}e^{-} \to \nu\bar{\nu}\gamma$. We consider several sets of machine parameters: centre of mass energies $\sqrt{s}$…
Single- and multi-photon events with missing energy are selected in 619/pb of data collected by the L3 detector at LEP at centre-of-mass energies between 189GeV and 209GeV. The cross sections of the process e^+e^- -> nu nu gamma (gamma) are…
At $e^+e^-$ and $ep$ colliders, the large fluxes of almost on-shell photons accompanying the lepton beams lead to the photoproduction of jets. As the centre-of-mass energy is increased, regions of smaller $x$ in the parton densities are…
Models with large extra dimensions as well as unparticle models could give rise to new phenomena at collider experiments due to real emission or virtual exchange of gravitons or unparticles. In this paper we present the common…
Precision experimental tests of the Standard Model of particle physics (SM) are one of our best hopes for discovering what new physics lies beyond the SM (BSM). Key in the search for new physics is the connection between theory and…
Extensions of the Standard Model (SM) of Particle Physics can be probed either through precision measurements of SM observables or via direct searches for processes beyond the SM (BSM). This proceeding focuses on precision measurements in…