The pp -> pp gamma reaction has been measured at a beam energy of 310 MeV by detecting both final protons in the PROMICE-WASA facility and identifying a missing-mass peak. For those events where the pp excitation is less than 3 MeV, the final diproton is almost purely in the 1S0 state and, under these conditions, there is complete coverage in the photon c.m. angle theta_gamma. The linear behaviour observed in cos^2(theta_gamma) shows that there is almost no influence of an E2 multipole at this energy, though the E1 and M2 must be rather similar in size.
@article{arxiv.0812.4250,
title = {Hard bremsstrahlung in the pp -> pp gamma reaction},
author = {A. Johansson and C. Wilkin},
journal= {arXiv preprint arXiv:0812.4250},
year = {2010}
}
Comments
An error in Eq.(1) is corrected. The conclusions of the paper are not changed in any significant way. Phys.Lett.B 673 (2009) 5 + erratum to appear