arXiv subjects

Hans O. U. Fynbo

Publications and source records attributed to Hans O. U. Fynbo.

3 recordsLinked to original sources

arXiv2020

Experimental study of the $^{11}\text{B}(p,3α)γ$ reaction at $E_p = 0.5-2.7$ MeV

Our understanding of the low-lying resonance structure in $^{12}$C remains incomplete. We have used the $^{11}\text{B}(p,3α)γ$ reaction at proton energies of $E_p=0.5-2.7$ MeV as a selective probe of the excitation region above the $3α$ threshold in $^{12}$C. Transitions to individual levels in $^{12}$C were identified by measuring the 3$α$ final state with a compact array of charged-particle detectors. Previously identified transitions to narrow levels were confirmed and new transitions to broader levels were observed for the first time. Here, we report cross sections, deduce partial $γ$-decay widths and discuss the relative importance of direct and resonant capture mechanisms.

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arXiv2018

Three-body effects in the Hoyle-state decay

We use a sequential $R$-matrix model to describe the breakup of the Hoyle state into three $α$ particles via the ground state of $^8\mathrm{Be}$. It is shown that even in a sequential picture, features resembling a direct breakup branch appear in the phase-space distribution of the $α$ particles. We construct a toy model to describe the Coulomb interaction in the three-body final state and its effects on the decay spectrum are investigated. The framework is also used to predict the phase-space distribution of the $α$ particles emitted in a direct breakup of the Hoyle state and the possibility of interference between a direct and sequential branch is discussed. Our numerical results are compared to the current upper limit on the direct decay branch determined in recent experiments.

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arXiv2014

Consistency of 8B neutrino spectra

We identify and quantify systematic effects not accounted for in two previous measurements of the alpha-alpha relative-energy distribution in the beta decay of 8B, which can explain the apparent disagreement with respect to two newer measurements. This settles a current dispute concerning the shape of the 8B neutrino spectrum of importance to solar-neutrino studies.

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