FCC-ee: The Lepton Collider

Abstract

Centre d'études et d'expertise sur les risques, l'environnement, la mobilité et l'aménagement

Taming of preasymptotic small x evolution within resummation framework

“…The gluon Green's function needs to be convoluted with the impact factors, which will provide for the suitable initial conditions for the evolution. The predictions will be made for the energies which potentially could be achieved in the future high energy e + e − machines, for example like planned FCC-ee [56,57] or CLIC [58,64]. The diagram for the process of the γ * γ * scattering is indicated in Fig.…”

“…For the purpose of this analysis, we shall consider γ * γ * scattering [12,13]. Such process could be realized in the future e + e − collider, such as FCC-ee [56,57], or CLIC [58], with doubly tagged electrons in the final state. We compute this process using the BFKL resummed solution, and quantify the length of the preasymptotic regime.…”

Probing long-lived particles at Higgs factories

“…where β t i is the speed of the X i in the transverse direction with γ i its boost, and τ X is the lifetime of X. R I (R O ) is the inner (outer) radius of the inner detector, and L d is its half length. d res = 5 µm is the inner-tracker spatial resolution for both CEPC and FCC-ee [12,37]. As long as one of the LLPs travels inside the IT window, and decays before it leaves [38] while the geometries of the IDEA detectors of the FCC-ee are reproduced from Ref.…”

“…Other than the high-luminosity run at the LHC there are also proposals for the next generation e − e + colliders, such as CEPC [11], FCC-ee [12], and ILC [13]. These future colliders, if they can be approved, all involve an important phase of operation as a Higgs factory running at center-of-mass energies √ s = 240−250 GeV.…”

The effects of O(α2) initial state QED corrections to e+e− → γ⁎/Z⁎ at very high luminosity colliders

“…with σ e + e − (s ) the scattering cross section without the ISR QED corrections, α ≡ α(s) the fine structure constant and z = s /s, where s is the invariant mass of the produced (off-shell) γ/Z boson. These results are of phenomenological importance for the precision measurements of the Z resonance, high luminosity ZH production, and tt production at LEP1, and for future planned e + e − colliders such as ILC and CLIC [10], the FCC ee [11,12], the CEPC [13], and also for muon colliders [14].…”