Coulomb Dissociation of 27P at 498 A MeVan indirect measurement of the astrophysical 26Si(p,γ) reaction

Abstract

The astrophysical 26 Si(p,¿)27 P reaction is studied using the Coulomb dissociation technique. We performed a 27 P Coulomb Dissociation experiment at GSI, Darmstadt (28-May-5 June 2007) using the ALADIN-LAND setup which allows complete-kinematic studies. A secondary 27 P beam at 498 AMeV impinging a 515mg/cm2 Pb target. The relative energy of the outgoing system (26 Si+p) is measured obtaining the resonant states of the 27 P. Four states are measured at 0.36±0.07, 0.88±0.09, 1.5±0.2, 2.1±0.3 MeV and there is evidence of a higher state at around 3.1 MeV. The angular distributions were also measure to be compared to the theoretical calculations and as a crosscheck of the measurements. The total cross section obtained for relative energies between 0 a 3 MeV has been measured and yields 55±7 mb. The resonance strength and radiative widths for the di¿erent resonant states are calculated and compare to previous measurements and theoretical predictions. Astrophysical implications about the competition of our reaction and the ß decay of the are also explained concluding that in stellar conditions the capture reaction dominates.