New constraints on R_p violating couplings via susy accompanied neutrino exchange mechanism of neutrinoless double beta decay

We consider ββ_0v decay induced by light Majorana neutrino exchange between decaying nucleons, accompanied by, in particular, the slepton exchange inside a nucleon. This contribution to ββ_0v is generated from the R_p violating terms and the mixing of the standard light neutrinos with neutral heavy particles or light sterile neutrinos. To determine the unknown mixing factor Δ, we take into account the four-neutrino model with three ordinary neutrinos and one sterile neutrino. Imposing the current experimental lower half-life limit, a set of constraints on λ′₃₁₁λ₁₂₃ and λ′₃₁₁λ₁₃₃ is obtained. Comparing with the limits on the products of the individual bounds on λ and λ′, we find that the former is stronger while the latter is weaker.