Neutron polarizabilities investigated by quasi-free Compton scattering from the deuteron

Measuring Compton scattered photons and recoil neutrons in coincidence, quasifree Compton scattering by the neutron has been investigated at MAMI (Mainz) at ${\ensuremath{\theta}}_{\ensuremath{\gamma}}^{\mathrm{lab}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}136\ifmmode^\circ\else\textdegree\fi{}$ in an energy range from 200 to 400 MeV. From the data a polarizability difference of ${\ensuremath{\alpha}}_{n}\ensuremath{-}{\ensuremath{\beta}}_{n}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}9.8\ifmmode\pm\else\textpm\fi{}3.6(\mathrm{stat}{)}_{\ensuremath{-}1.1}^{+2.1}(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}2.2(\mathrm{model})$ in units of ${10}^{\ensuremath{-}4}{\mathrm{fm}}^{3}$ has been determined. In combination with the polarizability sum ${\ensuremath{\alpha}}_{n}+{\ensuremath{\beta}}_{n}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}15.2\ifmmode\pm\else\textpm\fi{}0.5$ deduced from photoabsorption data, the first precise results for the neutron electric and magnetic polarizabilities, ${\ensuremath{\alpha}}_{n}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}12.5\ifmmode\pm\else\textpm\fi{}1.8(\mathrm{stat}{)}_{\ensuremath{-}0.6}^{+1.1}(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}1.1(\mathrm{model})$ and ${\ensuremath{\beta}}_{n}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2.7\ensuremath{\mp}1.8(\mathrm{stat}{)}_{\ensuremath{-}1.1}^{+0.6}(\mathrm{syst})\ensuremath{\mp}1.1(\mathrm{model})$, are obtained.