$Nd\to{^3H}\gamma$ with Effective Field Theory

Abstract

The cross section of neutron-deuteron radiative capture $n d\to {^3H}\gamma$ is calculated at energies relevant to Big-Bang nucleosynthesis ($ 20 \leq E \leq 200 $ Kev) with pionless Effective Field Theory. At these energies, magnetic transition M1 gives the dominant contribution. The M1 amplitude is calculated up to next-to-next-to leading order(N$^2$LO) with insertion of three-body force. Results are in good agreement within few percent theoretical uncertainty in comparison with available calculated data below E=200 Kev.