CP violation with a GeV-scale Majorana neutrino in Λb → (Λc+, p+)π+ μ- μ- decays

We explore the possibility of CP violation in baryonic Lambda(b) -> (Lambda(+)(c), p(+))pi(+) mu(-) mu(- ) decays which are mediated by two Majorana sterile neutrinos and are vertical bar Delta L vertical bar = 2 lepton-number-violating processes. Appreciable CP asymmetry can be obtained if there are two on-shell Majorana neutrinos that are quasidegenerate in mass with the mass difference of the order of average decay widths. We find that, given the present constraints on the heavy to light mixing element vertical bar V-mu N vertical bar, the Lambda(b) -> p(+) pi(+) mu(-) mu(- ) and Lambda(b) -> Lambda(+)(c) pi(+) mu(-) mu(- ) decay rates are suppressed but could be within the experimental reach at the LHC. If searches of the modes are performed, then experimental limits on the rates can be translated to constraints on the Majorana neutrino mass m(N) and heavy to light mixing clement squared vertical bar V-mu N vertical bar(2). We show that the constraints on the (m(N), vertical bar V-mu N vertical bar(2)) parameter space coming from the vertical bar Delta L vertical bar = 2 baryonic decays are complementary to the bounds coming from other processes.

Automated summary

The study investigates the CP violation in baryonic Lambda(b) decays mediated by Majorana neutrinos, showing that experimental searches could provide constraints on neutrino mass and mixing elements. The results suggest that the constraints from baryonic decays are complementary to bounds from other processes in the parameter space.