Abstract
An effective field theory calculation of the np→dγ cross section accurate to 1% for center of mass energies E≲1 MeV is presented. At these energies, which are relevant for big-bang nucleosynthesis, isovector magnetic dipole transitions M1 V and isovector electric dipole transitions E1 V give the dominant contributions. The M1 V amplitude is calculated up to next-to-next-to-leading order (N 2 LO), and the contribution from the associated four-nucleon–one-photon operator is determined from the cold neutron capture rate. The E1 V amplitude is calculated up to N 4 LO. The four-nucleon–one-photon operator contribution to E1 V is determined from the related deuteron photodisintegration reaction γd→np .
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
