Spectroscopic factor of the 7He ground state

The neutron spectroscopic factor SnSn of the 7He ground state is extracted from an R-matrix analysis of a recent measurement of the 7Li(d, 2He)7He reaction with good energy resolution. The width extracted from a deconvolution of the spectrum is Γ=183(22) keVΓ=183(22) keV (full width at half maximum, FWHM). The result Sn=0.64(9)Sn=0.64(9) is slightly larger than predictions of recent ‘ab initio’ Green's function Monte Carlo and fermionic molecular dynamics calculations.