On the Weak Decay of Composite System based on Majorana Partners
  In a composite model of leptons and quarks, composite particles with heavy Majorana particles appear provided that the V-rishon is regarded as a Majorana particle. In this paper, the decay mode of such "Majorana partners" is isestigated. It is shown that the life time of Majorana partners are fairly long. Our model suggests that a new mechanism of proton decay is possible, where the X and Y bosons in GUTs are not necessary. 
M. Aoki and K. Koike