Neutrinos and collider physics

Abstract

We review the collider phenomenology of neutrino physics and the synergetic aspects at energy, intensity and cosmic frontiers to test the new physics behind the neutrino mass mechanism. In particular, we focus on seesaw models within the minimal setup as well as with extended gauge and/or Higgs sectors, and on supersymmetric neutrino mass models with seesaw mechanism and with Rparity violation. In the simplest type-I seesaw scenario with sterile neutrinos, we summarize and update the current experimental constraints on the sterile neutrino mass and its mixing with the active neutrinos. We also discuss the future experimental prospects of testing the seesaw mechanism at colliders and in related low-energy searches for rare processes, such as lepton flavor violation and neutrinoless double beta decay. The implications of the discovery of lepton number violation at the Large Hadron Collider for leptogenesis are also studied.

Global constraints on a heavy neutrino

“…This scenario is very strongly constrained (see, for example, Refs. [2][3][4][5][94][95][96][97][98][99][100][101]). However, constraints using the ν 4 decay products are model-specific.…”

“…Because we focus on an fourth neutrino with mass m 4 10 eV, the associated oscillations are typically too rapid to resolve experimentally. 5 Even so, the oscillations of the three light neutrinos would be "non-unitary," meaning the oscillation probability for only three light neutrinos is distinctly different from the oscillation probability for three light neutrinos and one heavy neutrino [83,85]. If ν 4 has a negligible probability of decaying along its length of flight (and if the light neutrinos do not decay), then the probability for the oscillation ν α → ν β is…”

“…For example, we note that some analyses, e.g., Refs. [2,3,5], include both constraints from experimental searches for specific decay products of the heavy neutrino, and constraints that assume that the heavy neutrino does not decay visibly, such as searches for the kinematic signatures of a heavy neutrino in meson decay. Here, we pay close attention to the assumptions regarding the decay of the heavy neutrino in order to present self-consistent results.…”

Radiatively induced Fermi scale and unification

“…This would naturally lead to Dirac masses for neutrinos. More generally, various seesaw scenarios can also be realized in this setup and studied in connection with collider phenomenology [20]. For example, one could gauge the full chiral symmetry subgroup SUð2Þ L × SUð2Þ R [or even the entire SUð4Þ χ ].…”

Surveying the SO(10) model landscape: The left-right symmetric case

“…As a first approach, we will take the two-step breaking from SOð10Þ with the left-right symmetry group SUð3Þ C × SUð2Þ L × SUð2Þ R × Uð1Þ B−L at an intermediate scale, because some of its minimal realizations have been analyzed extensively in the literature, see e.g. [11][12][13]28,[40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57]. Other two-step breaking chains, such as those that go through SUð5Þ, may lead to similar situations with added difficulties such as three-way gauge coupling unification and rapid proton decay.…”