Eur. Phys. J. A (2018) 54: 138
https://doi.org/10.1140/epja/i2018-12577-3

Regular Article - Experimental Physics

The partial widths of the 16.1 MeV 2⁺ resonance in ¹²C

Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Aarhus, Denmark

^* e-mail: mm@phys.au.dk

Received: 30 May 2018
Accepted: 30 July 2018
Published online: 27 August 2018

Abstract

The 16.1 MeV resonance in ¹²C situated slightly above the proton threshold can decay by proton, , and emission. The partial width for proton emission cannot be directly measured due to the low proton energy and the small branching ratio. Instead it must be indirectly derived from other observables. However, due to several inconsistent data the derived partial width varies by almost a factor 2 depending on the data used. Here we trace the majority of this inconsistency to different measurements of the cross sections. We have remeasured this cross section using modern large area silicon strip detectors allowing to measure all final state particles, which circumvents a normalization issue affecting some of the previous measurements. Based on this we determine eV. We discuss the implications for other observables related to the 16.1 MeV resonance and for isospin symmetry in the A = 12 system. In addition, we conclude that the dataset currently used for the NACRE and NACRE II evaluation of the ¹¹B(p, ) reaction should be scaled by a factor of 2/3. This impacts the reaction rate accordingly.