Exploring the potential of FCC-hh to search for particles from $B$ mesons

Abstract

The Future Circular Collider (FCC-hh) is a proposed successor of the Large Hadron Collider (LHC). FCC-hh would push both the energy and intensity frontiers of searches for new physics particles. In particular, due to higher energy and luminosity than at the LHC, at FCC-hh there would be produced around 30 times larger amount of B mesons and 120 times of W bosons, which then may decay into feebly interacting particles. In this paper we demonstrate the potential of FCC-hh by studying its sensitivity to heavy neutral leptons (HNLs) with masses m N < m B . We consider various locations of a displaced decay volume embedded in the planned infrastructure of FCC-hh. We demonstrate that FCC-hh may substantially improve the reach of the parameter space of HNLs as compared to the searches proposed at the LHC.

The present and future status of heavy neutral leptons

“…The two configurations of the setup, the one with detectors covering |η| < 1.5 (the mid-η 1 experiment) and another one 1.5 < |η| < 2.6 (the mid-η 2 experiment), are shown in figure 21. Due to the large solid angle coverage and small mean γ factors of HNLs flying in the direction of these detectors, such configurations may extend the exclusion region by an order of magnitude and larger beyond that of SHiP and LHC-based experiments, which is also well below the FCC-ee reach for m N < m B [514].…”

“…[144] and references therein as well as section 2.3. Colourful lines: estimated sensitivities of the main detectors at the HL-LHC [85,451,723,724] and NA62 [139], compared to the sensitivities of selected proposed experiments (FASER2 [484], DUNE [600], MATHUSLA [482], SHiP [515,595], CODEX-b [480], see [64] for a more comprehensive list) as well as selected future colliders (ILC [523,725], FCC-ee or CEPC [506,516,726], FCC-hh [85,507,514,727], muon colliders [728], LHeC and FCC-he [519], where DV indicates displaced vertex searches). The curves from [506,723,726] have been re-scaled to an integrated luminosity consistent with [85,451,516].…”

“…The curves from [506,723,726] have been re-scaled to an integrated luminosity consistent with [85,451,516]. The sensitivity of future colliders could be considerably improved with dedicated long-lived particle detectors [510,511,514,729]. Cartan theory [289].…”

“…The curves from[506,723,726] have been re-scaled to an integrated luminosity consistent with[85,451,516]. The sensitivity of future colliders could be considerably improved with dedicated long-lived particle detectors[510,511,514,729].Brown band: lower bound on the total HNL mixing U U U e 2 2 2 + + m t from the requirement to explain the light neutrino properties [40]. The band width indicates the range obtained by varying the lightest neutrino mass and light neutrino mass ordering.…”

First evaluation of meson and τ lepton spectra and search for heavy neutral leptons at ILC beam dump

“…Among studies of the future HNL searches, we include projected sensitivities at FASER2 [72], NA62 [1], DUNE [40], SHiP [8], and MATHUSLA [42] in figures 5, 7, and 8 to compare to the sensitivities at the ILC beam dump experiment. Other experiments including LHCb [73,74], Codex-b [75], Belle II [66], Dark-Quest [76], IceCube [77], ATLAS and CMS at HL-LHC [68,71,78], and FCC-hh [79] can also search for the HNLs beyond the current experimental constrains.…”