First Direct Measurement of an Astrophysical <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi></mml:math>-Process Reaction Cross Section Using a Radioactive Ion Beam
G. Lotay, S. A. Gillespie, M. Williams, T. Rauscher, M. Alcorta, A. M. Amthor, C. Andreoiu, D. Baal, G. C. Ball, S. S. Bhattacharjee, Hadi Behnamian, V. Bildstein, C. Burbadge, W. N. Catford, D. T. Doherty, N. E. Esker, F. H. Garcia, A. B. Garnsworthy, G. Hackman, S. Hallam, Kevan Hudson, S. Jazrawi, Eva Kasanda, A. Kennington, Yeo Hyung Kim, A. Lennarz, R. S. Lubna, C. R. Natzke, Nobuya Nishimura, B. Olaizola, C. Paxman, A. Psaltis, C. E. Svensson, J. Williams, B. Wallis, D. Yates, D. Walter, B. Davids
Abstract
We have performed the first direct measurement of the ^{83}Rb(p,γ) radiative capture reaction cross section in inverse kinematics using a radioactive beam of ^{83}Rb at incident energies of 2.4 and 2.7A MeV. The measured cross section at an effective relative kinetic energy of E_{cm}=2.393 MeV, which lies within the relevant energy window for core collapse supernovae, is smaller than the prediction of statistical model calculations. This leads to the abundance of ^{84}Sr produced in the astrophysical p process being higher than previously calculated. Moreover, the discrepancy of the present data with theoretical predictions indicates that further experimental investigation of p-process reactions involving unstable projectiles is clearly warranted.