Phenomenology of the simplest linear seesaw mechanism
Aditya Batra, Praveen Bharadwaj, Sanjoy Mandal, Rahul Srivastava, J. W. F. Valle
Abstract
A bstract The linear seesaw mechanism provides a simple way to generate neutrino masses. In addition to Standard Model particles, it includes quasi-Dirac leptons as neutrino mass mediators, and a leptophilic scalar doublet seeding small neutrino masses. Here we review its associated physics, including restrictions from theory and phenomenology. The model yields potentially detectable μ → eγ rates as well as distinctive signatures in the production and decay of heavy neutrinos ( N i ) and the charged Higgs boson ( H ± ) arising from the second scalar doublet. We have found that production processes such as e + e − → NN , e − γ → NH − and e + e − → H + H − followed by the decay chain $$ {H}^{\pm}\to {\ell}_i^{\pm }N $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>H</mml:mi> <mml:mo>±</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:msubsup> <mml:mi>ℓ</mml:mi> <mml:mi>i</mml:mi> <mml:mo>±</mml:mo> </mml:msubsup> <mml:mi>N</mml:mi> </mml:math> , $$ N\to {\ell}_j^{\pm }{W}^{\mp } $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>N</mml:mi> <mml:mo>→</mml:mo> <mml:msubsup> <mml:mi>ℓ</mml:mi> <mml:mi>j</mml:mi> <mml:mo>±</mml:mo> </mml:msubsup> <mml:msup> <mml:mi>W</mml:mi> <mml:mo>∓</mml:mo> </mml:msup> </mml:math> leads to striking lepton number violation signatures at high energies which may probe the Majorana nature of neutrinos.