Possible evidence of extended objects inside the proton

Abstract

Recent experimental determinations of the Nachtmann moments of the inelastic structure function of the proton, ${F}_{2}^{p}{(x,Q}^{2}),$ obtained at Jefferson Lab, are analyzed for values of the squared four-momentum transfer ${Q}^{2}$ ranging from $\ensuremath{\approx}0.1$ to $\ensuremath{\approx}2(\mathrm{GeV}{/c)}^{2}.$ It is shown that such inelastic proton data exhibit a new type of scaling behavior and that the resulting scaling function can be interpreted as a constituent form factor consistent with the elastic nucleon data. These findings suggest that at low momentum transfer the inclusive proton structure function originates mainly from the elastic coupling with extended objects inside the proton. We obtain a constituent size of $\ensuremath{\approx}0.2--0.3\mathrm{fm}.$