Related papers: What is the scale of new physics behind the muon $…
Motivated by the long-standing discrepancy between the Standard Model prediction and the experimental measurement of the muon magnetic dipole moment, we have recently proposed to interpret this muon $g-2$ anomaly in terms of the loop effect…
Motivated by the recent hints of lepton flavour non-universality in $B$-meson semi-leptonic decays, we study the constraints of perturbative unitarity on the new physics interpretation of the anomalies in $b \to c \ell \bar \nu$ and $b \to…
Assuming that the scale of new physics exceeds the weak scale, we have considered all possible origins of deviations from the Standard Model in $\gmu2$. If the underlying theory can be treated perturbatively, then to account for an effect…
The long-standing muon g-2 anomaly can be explained by heavy new physics particles through chirally enhanced contributions. It has been recently proposed that a muon collider running at center-of-mass energies of several TeV could test…
A non-universal $U(1)_{X}$ extension to the Standard Model composed of two scalar doublets and two scalar singlets together with three additional quark singlets and two lepton singlets and three generations of right-handed and Majorana…
In this paper we study the implications of the recent high precision measurement of (g-2)_{\mu} by BNL on new heavy physics beyond the SM in a model independent way. We find that if the new physics responsible for the muon anomaly is due to…
We comprehensively study all viable new-physics scenarios that resolve the muon $(g-2)_\mu$ anomaly with only Standard Model singlet particles coupled to muons via renormalizable interactions. Since such models are only viable in the MeV --…
The longstanding muon g-2 anomaly may indicate the existence of new particles that couple to muons, which could either be light (< GeV) and weakly coupled, or heavy (>> 100 GeV) with large couplings. If light new states are responsible,…
While the muon $g-2$ anomaly can be successfully explained by some new physics models, most of them are severely constrained by the $\mu \to e \gamma$ bound. This tension is more transparent from the effective field theory perspective, in…
We study two-to-two scattering amplitudes of a scalar particle of mass $m$. For simplicity, we assume the presence of $\mathbb{Z}_2$ symmetry and that the particle is $\mathbb{Z}_2$ odd. We consider two classes of amplitudes: the fully…
We present a comprehensive reassessment of perturbative unitarity bounds in the dimension-six Standard Model Effective Field Theory, exploiting a new formalism based on spinor-helicity techniques to derive partial-wave unitarity bounds for…
The $4.2\sigma$ discrepancy in the $(g-2)$ of the muon provides a hint that may indicate that physics beyond the standard model is at play. A multi-TeV scale muon collider provides a natural testing ground for this physics. In this paper,…
Two next generation muon $g-2$ experiments at Fermilab in the US and at J-PARC in Japan have been designed to reach a four times better precision from 0.54 ppm to 0.14 ppm and the challenge for the theory side is to keep up in precision as…
The long-standing $4.2 \, \sigma$ muon $g-2$ anomaly may be the result of a new particle species which could also couple to dark matter and mediate its annihilations in the early universe. In models where both muons and dark matter carry…
We consider a flavour conserving two Higgs doublet model that consists of a type I (or X) quark sector and a generalized lepton sector where the Yukawa couplings of the charged leptons to the new scalars are not proportional to the lepton…
A secluded U(1) sector with weak admixture to photons, O(10^{-2}-10^{-3}), and the scale of the breaking below 1 GeV represents a natural yet poorly constrained extension of the Standard Model. We analyze g-2 of muons and electrons together…
In very high energy scattering events production of multiple Higgs and electroweak gauge bosons becomes possible. Indeed the perturbative cross section for these processes grows with increasing energy, eventually violating perturbative…
The long-standing discrepancy of muon $g-2$ is a hint of new physics beyond the standard model of particle physics. In this letter we show that heavy new physics contribution can be fully tested at a muon collider with center-of-mass energy…
We consider a type I or type X two Higgs doublets model with a modified lepton sector. The generalized lepton sector is also flavor conserving but with the new Yukawa couplings completely decoupled from lepton mass proportionality. The…
We investigate the possibility to interpret the muon $g-2$ anomaly in terms of a massive spin-2 particle, $G$, which can be identified as the first Kaluza-Klein graviton in the generalized Randall-Sundrum model. In particular, we obtain the…