With the establishment and maturation of the experimental programs searching for new
physics with sizeable couplings at the LHC, there is an increasing interest in the broader …

Neutrinoless double-beta decay is a forbidden, lepton-number-violating nuclear transition
whose observation would have fundamental implications for neutrino physics, theories …

The existence of nonzero neutrino masses points to the likely existence of multiple Standard
Model neutral fermions. When such states are heavy enough that they cannot be produced …

Abstract Particles beyond the Standard Model (SM) can generically have lifetimes that are
long compared to SM particles at the weak scale. When produced at experiments such as …

The Majorana nature of neutrinos is strongly motivated from the theoretical and
phenomenological point of view. A plethora of neutrino mass models, known collectively as …

Neutrinoless double beta decay (0 ν β β) is a crucial test for lepton number violation.
Observation of this process would have fundamental implications for neutrino physics …

We for the first time map the range of active-sterile neutrino mixing angles in which
leptogenesis is possible in the type I seesaw model with three heavy neutrinos with …

We study the prospects for discovering heavy neutral leptons at Forward Search Experiment
(FASER), the newly proposed detector at the LHC. Previous studies showed that a relatively …

This report, as part of the 2021 Snowmass Process, summarizes the current status of collider
physics at the Energy Frontier, the broad and exciting future prospects identified for the …

We present the activities of the" New Physics" working group for the" Physics at TeV
Colliders" workshop (Les Houches, France, 30 May-17 June, 2011). Our report includes new …