Related papers: Probing $\tau$ lepton dipole moments at future Lep…
LEP precision on electroweak measurements was sufficient not to hamper the extraction of Higgs couplings at the LHC. But the foreseen permille-level Higgs measurements at future lepton colliders might suffer from parametric electroweak…
In this work we study the potential of the processes $e^+e^- \to e^+\gamma^* e^- \to e^+\tau \bar\nu_\tau \nu_e $ and $e^+e^- \to e^+\gamma^* \gamma^* e^- \to e^+\nu_\tau \bar\nu_\tau e^- $ at a future high-energy and high-luminosity linear…
We describe recent work on the physics of the Higgs boson at future muon colliders. Starting from the low energy muon collider at the Higgs boson pole we extend our discussion to the multi-TeV muon collider and outline the physics case for…
Electric dipole moments are extremely sensitive probes of physics beyond the Standard Model. A vibrant experimental program is in place, with the goal of improving existing bounds on the electron and neutron electric dipole moments by one…
One of the key assumptions of the Standard Model of fundamental particles is that the interactions of the charged leptons, namely electrons, muons, and taus, differ only because of their different masses. While precision tests comparing…
We investigate the prospects of the search for a nonzero $\tau$ EDM form factor $d_\tau(s)$ in $\tau$ pair production by $e^+ e^-$ collisions at BEPC-II collider energies. We compute the expectation values and covariances of simple and…
Muons offer a unique opportunity to build a compact high-energy electroweak collider at the 10 TeV scale. A Muon Collider enables direct access to the underlying simplicity of the Standard Model and unparalleled reach beyond it. It will be…
In a previous work \cite{Buttazzo:2020ibd}, it has been pointed out that heavy new physics (NP) contributions to lepton dipole moments and high-energy cross-sections of lepton pairs into Higgs and $\gamma/Z$ bosons are connected, if the…
A search for beyond the standard model spin-0 bosons, $\phi$, that decay into pairs of electrons, muons, or tau leptons is presented. The search targets the associated production of such bosons with a W or Z gauge boson, or a top…
Precise measurements of the lepton properties provide stringent tests of the Standard Model and accurate determinations of its parameters. We overview the present status of tau physics, highlighting the most recent developments, and discuss…
We analyze different observables to study the magnetic dipole moment of the tau pairs produced by photon linear colliders. We use the circular polarized photon beam and study distributions of polarized $\tau$ final pairs to define sensibly…
We obtain limits on the electromagnetic and weak dipole moments of the tau-lepton in the framework of a Left-Right symmetric model (LRSM) and a class of $E_6$ inspired models with an additional neutral vector boson $Z_\theta$. Using as an…
Expected precisions of measurements of the elastic scattering cross sections are estimated for $\mu^+ \mu^+$ and $\mu^+ e^-$ colliders, which are recently proposed as future realistic possibilities ($\mu$TRISTAN). Comparing with…
A search for a pair of low-mass pseudoscalars $a$ that promptly decay into $\tau$-leptons is presented using 140 fb$^{-1}$ of proton-proton collision data at $13$ TeV centre-of-mass energy recorded with the ATLAS detector at the Large…
We study the observability for a lepton flavor-changing decay of a Higgs boson $h\to \mu\tau$ at hadron colliders. Flavor-changing couplings of a Higgs boson exist at tree level in models with multiple Higgs doublets. The $h\mu\tau$…
The Higgs-portal lepton flavor violation is studied in a vectorlike lepton model. For evading the constraints from rare $Z\to \ell^\pm_i \ell^\mp_j$ decays, we introduce two triplet vectorlike leptons, $(1,3)_{-1}$ and $(1,3)_{0}$. The…
Among the post-LHC generation of particle accelerators, the muon collider represents a unique machine with capability to provide very high energy leptonic collisions and to open the path to a vast and mostly unexplored physics programme.…
We summarize the potential of muon colliders to probe fundamental physics. $W^+W^-$, \bar tt, and $Zh$ threshold measurements could determine masses to precisions $\Delta M_W = 6$ MeV, $\Delta m_t = 70$ MeV, and $\Delta m_h = 45$ MeV, to…
We calculate the total cross sections and probabilities of electromagnetic productions of electron, muon and tauon pair productions simultaneously. At the Large Hadron Collider (LHC), the available electromagnetic energy is sufficient to…
In a two Higgs doublet model with extra Yukawa couplings, we assess the new physics contributions to charged lepton electric dipole moment. We focus especially on muon (and tau) EDM where in the coming decade several experiments $-$ Muon…