Relativistic Structure of the Deuteron: 1. Electro-disintegration and Y-scaling

Realistic solutions of the spinor-spinor Bethe-Salpeter equation for the deuteron with realistic interaction kernel including the exchange of π, σ, ω, ρ, η and δ mesons, are used to systematically investigate relativistic effects in inclusive quasi-elastic electron-deuteron scattering within the relativistic impulse approximation. Relativistic y-scaling is considered by generalising the non relativistic scaling function to the relativistic case, and it is shown that y-scaling does occur in the usual relativistic scaling variable resulting from the energy conservation in the instant form of dynamics. The present approach of y-scaling is fully covariant, with the deuteron being described by −+ 1 waves. It is demonstrated that if the negative relative energy states 1 P 1 , 3 P 1 are disregarded, the concept of covariant momentum distributions N(p 0 , p), with p 0 = M D /2 − p 2 + m 2 , can be introduced, and that calculations of electro-disintegration cross section in terms of these distributions agree within few percents with the exact calculations which include the 1 P 1 , 3 P 1 states, provided the nucleon three momentum |p| ≤ 1GeV /c; in this momentum range, the asymptotic relativistic scaling function is shown to coincide with the longitudinal covariant momentum distribution.