%0 Journal Article %T Delta L >= 4 lepton number violating processes %A Fonseca, R. M. %A Hirsch, M. %J Physical Review D %D 2018 %V 98 %N 1 %I Amer Physical Soc %@ 2470-0010 %G English %F Fonseca+Hirsch2018 %O WOS:000439791500005 %O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=3675), last updated on Thu, 09 Aug 2018 00:17:13 +0000 %X We discuss the experimental prospects for observing processes which violate lepton number (Delta L) in four units ( or more). First, we reconsider neutrinoless quadruple beta decay, deriving a model independent and very conservative lower limit on its half- life of the order of 10(41) ys for Nd-150. This renders quadruple beta decay unobservable for any feasible experiment. We then turn to a more general discussion of different possible low-energy processes with values Delta L >= 4. A simple operator analysis leads to rather pessimistic conclusions about the observability at low-energy experiments in all cases we study. However, the situation looks much brighter for accelerator experiments. For two example models with Delta L = 4 and another one with Delta L = 5, we show how the LHC or a hypothetical future pp collider, such as the FCC, could probe multilepton number violating operators at the TeV scale. %R 10.1103/PhysRevD.98.015035 %U http://arxiv.org/abs/1804.10545 %U https://doi.org/10.1103/PhysRevD.98.015035 %P 015035-12pp