Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $S$-factor and scattering-parameter extractions from ${}^{3}\mathrm{He}
  +{}^{4}\mathrm{He} \rightarrow {}^{7}\mathrm{Be} + \gamma$   Previous studies of the reaction ${}^{3}\mathrm{He} +{}^{4}\mathrm{He}
\rightarrow {}^{7}\mathrm{Be} + \gamma$ have focused on providing the best
central value and error bar for the $S$ factor at solar energies. Measurements
of this capture reaction, the ${}^{3}\mathrm{He}$-${}^{4}\mathrm{He}$
scattering phase shifts, as well as properties of ${}^{7}\mathrm{Be}$, have
been used to constrain employed theoretical models. Here we show that much more
information than was previously appreciated can be extracted from
angle-integrated capture data alone. We use the next-to-leading-order (NLO)
amplitude in an effective field theory (EFT) for the reaction to perform the
extrapolation. At this order the EFT describes the reaction using an s-wave
scattering length and effective range, the asymptotic properties of the final
bound states, and short-distance contributions to the $E1$ capture amplitude.
We extract the multi-dimensional posterior of all these parameters via a
Bayesian analysis. We find that properties of the ${}^{7}\mathrm{Be}$ ground
and excited states are well constrained. The total $S$ factor $S(0)=
0.578^{+0.015}_{-0.016}$ keV~b, while the branching ratio for excited- to
ground-state capture at zero energy, $Br(0)=0.406^{+0.013}_{-0.011}$, both at
68\% degree of belief. This $S(0)$ is broadly consistent with other recent
evaluations, including the previously recommended value $S(0)=0.56 \pm 0.03$ eV
b, but has a smaller error bar. We also find significant constraints on the
scattering parameters, and we obtain constraints on the $S(E)$'s angular
dependence. The path forward seems to lie with better measurements of the
scattering phase shift and $S(E)$'s angular dependence, together with better
understanding of the asymptotic normalization coefficients of the ${}^7$Be
bound states' wave functions. Data on these could further reduce $S(0)$'s
uncertainty.

23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs