We propose a variant of seesaw mechanism by introducing extra singlet neutrinos, with which we show how the low scale leptogenesis is realized without imposing the tiny mass splitting between two heavy Majorana neutrinos required in the resonant leptogenesls. Thus, the so-called gravitino problem encountered in the typical supersymmetric seesaw model can be avoided. It is showed that an introduction of the new singlet fermion leads to a new contribution which can enhance the lepton asymmetry for certain range of parameter space.
Bibliographical noteFunding Information:
SKK is supported in part by the KOSEF SRC program through CQUeST with Grant No. R11-2005-021 and in part by the KRF Grant funded by the Korean Government (MOEHRD) (KRF-2006-003-C00069). CSK is supported in part by CHEP-SRC and in part by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD) No. KRF-2005-070-C00030.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Physics and Astronomy(all)