Asymmetry and Angular Distribution of Deuteron Photodisintegration in the 20–60 MeV Range

Abstract

Although deuteron photodisintegration has been studied extensively both experimentally and theoretically in the last fifty years, it continues to provide vital testing ground between new measurements and recent calculations incorporating corrections due to meson exchanges, isobar effects, and relativistic corrections, etc. The differences between theory and experimental measurements point to a need for new measurements employing polarized gamma rays. Recently such measurements on the cross section α(θ, φ) and polarization asymmetry Σ(θ) have been reported by De PASCALE et al. [1] in the 20–60 MeV gamma-ray energy range. We have attempted to fit their data by using the amplitude method of RUSTGI et al. [2]. The interaction Hamiltonian H′ for El, Ml, and E2 multipoles is written as

$$ H' = - e{E_x}A,\,A = \frac{1}{2}\left( {{{\vec{1}}_E} \cdot \vec{r}} \right) + \frac{i}{8}\left( {\vec{k} \cdot \vec{r}} \right)\left( {{{\vec{l}}_E} \cdot \vec{r}} \right) + \frac{{{f^2}}}{{4m}}\left[ {\frac{1}{3}\left( {{\phi_0}{{\vec{\sigma }}_1} \cdot {{\vec{\sigma }}_2} + {\phi_2}{S_{{12}}}} \right)\vec{r} + \left( {2{\mu_v}\phi - {\phi_1}} \right)\left[ {{{\vec{\sigma }}_1}\left( {{{\vec{\sigma }}_2} \cdot \vec{r}} \right) + {{\vec{\sigma }}_2}\left( {{{\vec{\sigma }}_1} \cdot \vec{r}} \right)} \right]} \right] \cdot {\vec{1}_E} + \frac{3}{2}\frac{{{f^2}}}{M}{\alpha_s}\left[ {{{\vec{\sigma }}_1}\left( {\vec{r} \cdot {{\vec{\sigma }}_2}} \right) - {{\vec{\sigma }}_2}\left( {\vec{r} \cdot {{\vec{\sigma }}_1}} \right)} \right] \cdot {\vec{1}_E} + \frac{{{f^2}}}{{2M}}\frac{1}{\mu } $$

(1)

$$ x\left[ {{\phi_0}\left[ {\left( {{{\vec{\sigma }}_2} \cdot \vec{\nabla }} \right)\left( {{{\vec{\sigma }}_1} \cdot \vec{r}} \right) + \left( {{{\vec{\sigma }}_1} \cdot \vec{\nabla }} \right)\left( {{{\vec{\sigma }}_2} \cdot \vec{r}} \right)} \right]\vec{r} + \frac{1}{3}\left[ {\left( {3{\phi_1} + {\phi_2}} \right)\left( {{{\vec{\sigma }}_1} \cdot {{\vec{\sigma }}_2}} \right) + {\phi_2}{S_{{12}}}} \right] \cdot \nabla } \right] \cdot {\vec{1}_E} - \frac{1}{{8{M^2}}}\left[ {\left( {2{\mu_v} - 1} \right)\left( {{{\vec{\sigma }}_1} + {{\vec{\sigma }}_2}} \right) + 2\left( {{\mu_s} - 1} \right)\left( {{{\vec{\sigma }}_1} + {{\vec{\sigma }}_2}} \right)} \right]x{\vec{P}_r} \cdot {\vec{1}_E} + \frac{h}{{2Mc}}\left[ {\left( {\frac{1}{2}{\mu_v} + {g_1} + {h_1}} \right)\left( {{{\vec{\sigma }}_1} - {{\vec{\sigma }}_2}} \right) + \frac{1}{2}\left( {{\mu_s} - \frac{1}{2}} \right)\left( {{{\vec{\sigma }}_1} + {{\vec{\sigma }}_2}} \right) + \left( {{g_{{II}}} + {h_{{II}}}} \right)T_{{12}}^{{\left( - \right)}}} \right] \cdot {\vec{1}_H} $$

(2)

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