Given the masses of various atomic particles
m_p = 1.0072 u, m_n = 1.0087 u, m_e = 0.000548 u,
= 0, m_d = 2.0141 u, where p proton,
n neutron,
e electron, antineutrino and
d deuteron. Which of the following process is
allowed by momentum and energy
conservation?