Related papers: Unambiguously Testing Positivity at Lepton Collide…
We discuss the sensitivity of the $\gamma \gamma \to \tau^+ \tau^-$ process in ultraperipheral Pb+Pb collisions on the anomalous magnetic ($a_{\tau}$) and electric ($d_{\tau}$) moments of $\tau$ lepton at LHC energies. We derive the…
Optical resonators provide a powerful tool for testing aspects of Lorentz invariance. Here, we present a reanalysis of an experiment where a path asymmetry was created in an optical ring resonator by introducing a dielectric prism in one…
Effective field theories in flat space and in anti-de Sitter space are constrained by causality and unitarity, often in the form of positivity bounds. Similar bounds have been harder to demonstrate in cosmological backgrounds, where the…
A complete list of operators contributing at the lowest order to Quartic Neutral Gauge Boson Couplings involving photons and Z-bosons, is presented. We show that, for the couplings we consider, the lowest order contribution is from…
Positivity constraints have proved to be important for spin observables of exclusive reactions involving polarized initial and final particles. Attention is focused in this note on the photoproduction of pseudoscalar mesons from spin 1/2…
We establish the bounds on Wilson coefficients of the Higgs effective field theory (HEFT) mandated by unitarity and analyticity. These positivity constraints can be projected into the space of the standard model effective field theory…
We present the complete set of positivity bounds on the Higgs Effective Field Theory (HEFT) at next-to-leading order (NLO). We identify the 15 operators that can be constrained by positivity, as they contribute to $s^2$-growth in the…
We perform a detailed study of the process $e^+e^-\to\gamma\nu_l\bar\nu_l$ and its sensitivity to anomalous gauge boson couplings of the $\gamma WW$ vertex. We concentrate on LEP II energies, $\sqrt{s}=200$ GeV, and energies appropria- te…
We study the sensitivity to physics beyond the standard model of precise top-quark pair production measurements at future lepton colliders. A global effective-field-theory approach is employed, including all dimension-six operators of the…
Dimuonium ($\mu^+ \mu^-$) is one of the pure QED bound systems of leptons, together with positronium and ditauonium. The former had been observed in experiment in 1951, while the search for dimuonium and ditauonium ($\tau^+ \tau^-$) are…
We examine the contributions of various couplings in general ZZH and gammaZH interactions arising from new physics to the Higgs production process e+e- --> HZ, followed by the decay of the Z into a charged-lepton pair. We take into account…
We propose to probe light-quark dipole interactions at lepton colliders using the azimuthal asymmetry of a collinear dihadron pair $(h_1h_2)$ produced in association with another hadron $h'$. This asymmetry, arising from quantum…
We consider the possibility that dark matter (DM) only interacts with the Standard Model leptons, but not quarks at tree level, and analyze the future lepton collider prospects of such leptophilic DM in the monophoton and mono-$Z$ (both…
Astrophysical bounds severely limit the possibility of observing collider signals of gravity with less than 3 flat extra dimensions. However, small distortions of the compactified space can lift the masses of the lightest graviton…
We investigate the measurement of non-standard ZZV (V = {\gamma}, Z) couplings through Z-boson pair production at the $e^+ e^-$ colliders. We adopt Standard Model Effective Field Theory (SMEFT) approach to study these anomalous neutral…
$SU(2)_L$-invariance links charged dilepton and dineutrino couplings. Phenomenological implications are worked out for flavor changing neutral currents involving strange, charm, beauty and top quark transitions in a model-independent way.…
We present the first study of the production of a Standard Model Higgs boson at a lepton collider in association with a pair of W bosons, $e^+_{} e^-_{} \to W^+_{} W^-_{} H$, in the inverse seesaw model. Taking into account all relevant…
We consider an extension of the Standard Model with two right-handed singlet fermions with mass at the electroweak scale that induce neutrino masses, plus a generic new physics sector at a higher scale $\Lambda$. We focus on the effective…
The phenomenological constraints on extra neutral gauge bosons at present and at future colliders are reviewed. Special attention is paid to the influence of radiative corrections, systematic errors, and kinematic cuts on the Z'…
In the Standard Model, the couplings between gauge bosons are tightly constrained by the principles of gauge symmetry and renormalizability. However, the presence of anomalous couplings suggests the possibility of new physics beyond the…