Population of ${}^{13}\mathrm{Be}$ in a nucleon exchange reaction

The neutron-unbound nucleus ${}^{13}\mathrm{Be}$ was populated with a nucleon exchange reaction from a 71 MeV/u secondary ${}^{13}\mathrm{B}$ beam. The decay-energy spectrum was reconstructed using invariant mass spectroscopy based on ${}^{12}\mathrm{Be}$ fragments in coincidence with neutrons. The data could be described with an $s$-wave resonance at $E_r=0.73\left(9\right)\mathrm{MeV}$ with a width of ${\mathrm{\Gamma }}_r=1.98\left(34\right)\mathrm{MeV}$ and a $d$-wave resonance at $E_r=2.56\left(13\right)\mathrm{MeV}$ with a width of ${\mathrm{\Gamma }}_r=2.29\left(73\right)\mathrm{MeV}$. The observed spectral shape is consistent with previous one-proton removal reaction measurements from ${}^{14}\mathrm{B}$.

Figure 1

Decay-energy spectrum of ${}^{13}\mathrm{Be}$ fit with two components. The solid black line is the sum of simulated decay-energy spectra from an $s$-wave resonance (short-dashed blue line) and a $d$-wave resonance (long-dashed red line) with parameters listed in the text. The insert shows the energy-dependent resolution (dotted purple line) and the overall efficiency (solid green line).

Figure 2

Decay-energy spectrum of ${}^{13}\mathrm{Be}$ fit with three components. The solid black line is the sum of simulated decay-energy spectra from an $s$-wave resonance (short-dashed blue line) and two $d$-wave resonances (long-dashed red line and dot-dashed green line) with parameters listed in the text.