FCC-hh: The Hadron Collider

Lepton collider indirect signatures of dark CP-violation

“…In order to illustrate such a phenomenology, we have defined several BPs, each embedding CP-violation, over the I(2+1)HDM parameter space, with varying mass splittings and coupling strengths in the inert sector, all compliant with available experimental data, from relic density, (in)direct DM searches and colliders. For three such BPs, we have quantified CP-violation effects entering three asymmetries which can all be defined in the qq → Z * → ZZ channel and measured at both the LHC (f = q) by the end of its lifetime (i.e., after the High Luminosity LHC [58,59] runs) and at future lepton colliders (f = e) such as the FCC-ee, ILC, CLiC or CEPC running at current design luminosities. Finally, we have illustrated that the hadronic cross sections are typically larger than the leptonic ones, so that it is quite possible that a first evidence of a CPviolating I(2+1)HDM will occur at the LHC rather than at the FCC-ee, ILC, CLiC or CEPC.…”

Neutrinoless double beta decay versus other probes of heavy sterile neutrinos

“…ATLAS and CMS have also conducted searches for the LNV same-sign dilepton + jets channel, W ± → ± N, N → ± jj [58,59]. Above the Z boson mass limits can be improved in future by ATLAS and CMS during the high luminosity (L = 3 ab −1 ) LHC phase (HL-LHC) and by a future √ s = 27 or 100 TeV Future Circular Collider (FCC-hh) [60,61]. Around the Higgs mass, there are also some limits from the SM Higgs decay to sterile neutrinos [62].…”

Doubly charged Higgs boson production at hadron colliders

“…We briefly remark that the O(100) zb cross sections at √ s = 100 TeV are incredibly tiny. However, the proposed integrated luminosity goals for such potential machines are of L = 30 − 50 −1 ab [51][52][53][54][55], indicating that O(3 − 5) triplet pairs with masses of O(10) TeV could be produced in such a collider.…”

“…In light of these impediments to studying the canonical Type II Seesaw model, we revisit the modeling of triplet Higgs boson production at current and proposed [51][52][53][54][55] hadron collider facilities. Though our work holds for all mass eigenstates arising from the scalar triplet field∆, for conciseness, we limit our investigation to the pair and associated production of the doubly charged scalar ∆ ±± .…”