Related papers: Tau-lepton Physics at the FCC-ee circular e$^+$e$^…
The FCC-ee phase of a Future Circular Collider is generating great interest due to its versatility, allowing the study of various electroweak thresholds, $Z$, $WW$, $ZH$, and $t \bar{t}$. Electroweak precision physics is complemented by…
The feasibility of observing ditauonium, the bound state of two tau leptons, at $e^+e^-$ colliders (BES III at $\sqrt{s} = 3.78$ GeV, Belle II at $\sqrt{s} = 10.6$ GeV, a future super tau-charm factory (STCF) at $\sqrt{s} \approx…
The anomalous magnetic moment of the tau lepton, $a_{\tau}$, represents a fundamental test of the Standard Model (SM) and a high-sensitivity probe for New Physics in the third generation of leptons. Due to the tau's extremely short…
The future lepton colliders proposed for the High Energy and Precision Frontier set stringent demands on theory. The most ambitious, broad-reaching and demanding project is the FCC-ee. We consider here the present status and requirements on…
A production of a pair of tau leptons in PbPb collisions at the FCC-hh collider is examined. The 95\% C.L. exclusion limits, as well as 3$\sigma$ and 5$\sigma$ sensitivity limits on the anomaly magnetic moment of the tau lepton $a_\tau$ and…
The feasibility of observing true tauonium, the bound state of two tau leptons, $\mathcal{T}_0\equiv(\tau^+\tau^-)_0$, via photon-photon collisions at $e^+e^-$ colliders and at the LHC, is studied. The production cross sections of the…
The production of $\tau\mu$ pairs in electron-positron collisions offers a powerful probe of lepton flavor violation. In this work, we calculate the $e^+ e^- \to \tau \mu$ cross section within the framework of the Standard Model Effective…
The Future Circular Collider in the $\mathrm{e^{+}e^{-}}$ configuration offers the opportunity to significantly improve SM measurements with dedicated runs at the Z-pole, WW threshold, ZH (240 GeV), and $\mathrm{t}\bar{\mathrm{t}}$…
This paper presents the prospects for a precise measurement of the branching fraction of the leptonic $B_{c}^+\to \tau^+ \nu_\tau$ decay at the Future Circular Collider (FCC-ee) running at the $Z$-pole. A detailed description of the…
In this paper, we present detailed studies on the feasibility at $pp$, $e^-p$ and $e^+e^-$ colliders for model-independent sensitivity estimates on the total cross-section and on the anomalous $\tau^+\tau^-\gamma$ interaction through the…
The next-generation lepton colliders, such as CEPC, FCC-ee, and ILC will make precision measurement of the Higgs boson properties. We first extract the Higgs coupling precision from Higgs observables at CEPC to illustrate the potential of…
We study the possibility of probing the existence of a light, invisible, axion-like particle (ALP) $a$ in leptonic decays of the $Z$ boson at the proposed high-energy $e^+e^-$ colliders, CEPC and FCC-ee. Both projects plan to run at the $Z$…
The associated production of a Higgs boson with a $Z$ boson in the collisions of electron and positron beams at Future Circular Collider (FCC-ee) have been studied. Here, the $Z$ boson decays into dileptons, while the Higgs boson decays to…
High-precision measurements of the lepton's electromagnetic dipole moments provide a powerful probe for testing the Standard Model. A non-zero value of the $\tau$ lepton's electric(weak) dipole moment ($d_{\tau}^{\gamma}$, $d_{\tau}^{Z}$)…
The FCC (Future Circular Collider) study represents a vision for the next large project in high energy physics, comprising an 80-100 km tunnel that can house a future 100 TeV hadron collider. The study also includes a high luminosity e+e-…
The expected precision on measuring the $\sigma(e^+ e^- \rightarrow ZH) \times Br(H\rightarrow W^+W^-)$ in the fully leptonic decay mode at the Future Circular Collider (FCC) is presented. We consider two FCC-ee scenarios: $\sqrt{s} =240$…
The lighter scalar tau lepton $\sti$ may be the lightest scalar lepton and therefore would be found earlier in future collider experiments. We point out the impact of the measurement of the mass and the mixing angle of $\st$ to discriminate…
The electron-positron stage of the Future Circular Collider, FCC-ee, is a frontier factory for Higgs, top, electroweak, and flavour physics. It is designed to operate in a 100 km circular tunnel built at CERN, and will serve as the first…
Measurements in $W^+W^-$ events at LEP2 and in $B$ hadron semileptonic decays at B factories and LHCb provide intriguing hints of a violation of lepton universality in the charged current coupling of tau leptons relative to those for…
In this work we assess the potential of discovering new physics by searching for lepton-flavour-violating (LFV) decays of the $Z$ boson, $Z\to \ell_i \ell_j$, at the proposed circular $e^+e^-$ colliders CEPC and FCC-ee. Both projects plan…