A
bstract
The future muon collider has the potential to discover feebly interacting particles in a wide range of masses above the electroweak scale. It is particularly suitable to search for heavy ...neutral leptons (HNLs), as their production cross section
σ
∼
m
W
−
2
is not suppressed by the new physics scale. We demonstrate that with the capacity to observe up to 10
5
events in the previously unexplored TeV mass range, the muon collider provides the means to measure the fraction of lepton number violating (LNV) processes with precision at the level of a percent. This capability enables elucidating the nature of HNLs, allowing us to differentiate between Majorana, Dirac, and non-minimal scenarios featuring multiple degenerate HNLs. We link the observed fraction of LNV processes to the parameters of the model with three degenerate HNLs, which could be responsible for generating baryon asymmetry in the Universe. Additionally, we present a simple estimate for the number of signal events, as well as analyze the feasibility of vector boson fusion processes in searches for HNLs.
Searches for new physics at SND@LHC Boyarsky, Alexey; Mikulenko, Oleksii; Ovchynnikov, Maksym ...
The journal of high energy physics,
03/2022, Volume:
2022, Issue:
3
Journal Article
Peer reviewed
Open access
A
bstract
SND@LHC is an approved experiment equipped to detect scatterings of neutrinos produced in the far-forward direction at the LHC, and aimed to measure their properties. In addition, the ...detector has a potential to search for new feebly interacting particles (FIPs) that may be produced in proton-proton collisions. In this paper, we discuss signatures of new physics at SND@LHC for two classes of particles: stable FIPs that may be detected via their scattering, and unstable FIPs that decay inside the detector. We estimate the sensitivity of SND@LHC to probe scatterings of leptophobic dark matter and decays of neutrino, scalar, and vector portal particles. Finally, we also compare and qualitatively analyze the potential of SND@LHC and FASER/FASER
ν
experiments for these searches.
A
bstract
The extension of the Standard Model with two gauge-singlet Majorana fermions can simultaneously explain two beyond-the-Standard-model phenomena: neutrino masses and oscillations, as well as ...the origin of the matter-antimatter asymmetry in the Universe. The parameters of such a model are constrained by the neutrino oscillation data, direct accelerator searches, big bang nucleosynthesis, and requirement of successful baryogenesis. We show that their combination still leaves an allowed region in the parameter space below the kaon mass. This region can be probed by the further searches of NA62, DUNE, or SHiP experiments.
A
bstract
The Future Circular hadron 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.
Future searches for new physics beyond the Standard Model are without doubt in need of a diverse approach and experiments with complementary sensitivities to different types of classes of models. One ...of the directions that should be explored is feebly interacting particles (FIPs) with masses below the electroweak scale. The interest in FIPs has significantly increased in the last ten years. Searches for FIPs at colliders have intrinsic limitations in the region they may probe, significantly restricting exploration of the mass range
m
FIP
<
5
-
10
GeV/c
2
. Beam dump-like experiments, characterized by the possibility of extremely high luminosity at relatively high energies and the effective coverage of the production and decay acceptance, are the perfect option to generically explore the “coupling frontier” of the light FIPs. Several proposals for beam-dump detectors are currently being considered by CERN for implementation at the SPS ECN3 beam facility. In this paper, we analyse in depth how the characteristic geometric parameters of a beam dump experiment influence the signal yield. We apply an inclusive approach by considering the phenomenology of different types of FIPs. From the various production modes and kinematics, we demonstrate that the optimal layout that maximises the production and decay acceptance consists of a detector located on the beam-axis, at the shortest possible distance from the target defined by the systems required to suppress the beam-induced backgrounds.
Can we use heavy nuclei to detect relic neutrinos? Mikulenko, Oleksii; Cheipesh, Yevheniia; Cheianov, Vadim ...
The European physical journal. A, Hadrons and nuclei,
09/2023, Volume:
59, Issue:
9
Journal Article
Peer reviewed
Open access
Recent analysis of the viability of solid state-based relic neutrino detectors has revealed the fundamental necessity for the use of heavy,
A
>
100
,
β
-decayers as neutrino targets. Of all heavy ...isotopes,
and
stand out for their sufficiently low decay energies, reasonable half-life times and stable daughter nuclei. However, the crucial bit of information, that is the soft neutrino capture cross-section is missing for both isotopes. The main reason for that is a particular type of
β
-decay, which precludes a simple link between the isotope’s half-life time and the neutrino capture rate. In light of the necessity for a reliable estimate of the capture rate – unimpeded by potentially devastating theoretical uncertainties – prior to using the isotope in a full-scale experiment, we propose an experimental method to bypass this difficulty and obtain the capture cross-section of a soft neutrino by a given isotope from the isotope’s
β
-spectrum.
We discuss the phenomenology of a pair of degenerate GeV-scale Heavy Neutral Leptons within the Left-Right Symmetric Model (LRSM) framework, with the third fermion serving as a dark matter candidate. ...We highlight the potential of the recently approved SHiP experiment to test the existence of the light DM species, and the signatures of lepton number violation as a possible experimental probe of the model in various experiments. Our findings include concrete predictions, in some part of the model's parameter space, for the effective right-handed couplings \((V^{R}_{e})^2:(V^{R}_{\mu})^2:(V^{R}_{\tau})^2 = 0.16:0.47:0.38\) (normal neutrino hierarchy), \(0.489 : 0.22 : 0.30\) (inverted hierarchy) of the degenerate pair.
The future muon collider has the potential to discover feebly interacting particles in a wide range of masses above the electroweak scale. It is particularly suitable to search for heavy neutral ...leptons (HNLs), as their production cross section \(\sigma \sim m_W^{-2}\) is not suppressed by the new physics scale. We demonstrate that the muon collider, with the capacity to observe up to \(10^5\) events in the previously unexplored TeV mass range, provides the means to measure the fraction of lepton number violating (LNV) processes with precision at the level of a percent. This capability enables elucidating the nature of HNLs, allowing us to differentiate between Majorana, Dirac, and non-minimal scenarios featuring multiple degenerate HNLs. We link the observed fraction of LNV processes to the parameters of the model with three degenerate HNLs, which could be responsible for generating baryon asymmetry in the Universe. Additionally, we present a simple estimate for the number of signal events, as well as analyze the feasibility of vector boson fusion processes in searches for HNLs.
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