$pp\to pp{\pi }^0$ near threshold in pionless effective theory

The total cross section of the $pp\to pp{\pi }^0$ reaction near threshold is calculated in pionless effective field theory with a di-baryon and external pions. The amplitudes for a leading one-body and subleading contact neutral pion production vertex are obtained including the initial and final state interactions. After estimating a low-energy constant in the contact vertex, we compare our results for the total cross section with the experimental data.