Extraction of the neutron structure function F2n from inclusive scattering data on composite nuclei

Abstract We consider a generalized convolution, linking structure functions (SF) F N 2 for nucleons, F A 2 for a physical nucleus and f PN , A for a nucleus, composed of point-nucleons. In order to extract F 2 n we employ data on F 2 p , A and the computed f PN , A . Only for Q 2 ≈3.5 GeV 2 do data permit the extraction of F 2 A ( x ,3.5) over a sufficiently wide x -range. Applying Mellin transforms, the above relation between SF turns into an algebraic one, which one solves for the Mellin transform of the unknown F 2 n . We present inversion methods leading to the desired F 2 n , all using a parametrization for C ( x , Q 2 )= F 2 n ( x , Q 2 )/ F 2 p ( x , Q 2 ). Imposing motivated constraints, the simplest parametrization leaves one free parameter C ( x =1, Q 2 ). For Q 2 =3.5 GeV 2 its average over several targets and different methods is 〈 C (1,3.5)〉=0.54±0.03. We argue that for the investigated Q 2 , C ( x →1,3.5) is determined by the nucleon-elastic (NE) part of SF. A calculation of the latter comes close to the extracted value. Both are close to the SU (6) limit u V ( x ,3.5)=2 d V ( x ,3.5) for parton distribution functions.