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تسجيل مستخدم جديدA Bayesian analysis of light-front models and the nucleons charmed sigma term
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We present the results of a recent analysis to study the nucleons charm sigma term, $sigma_{coverline{c}}$. We construct a minimal model in terms of light-front variables and constrain the range of possibilities using extant knowledge from deeply inelastic scattering (DIS) and Bayesian parameter estimation, ultimately computing $sigma_{coverline{c}}$ in an explicitly covariant manner. We find a close correlation between a possible nonperturbative component of the charm structure function, $F^{coverline{c}}_{2,, mathrm{IC}}$, and $sigma_{coverline{c}}$. Independent of prescription for the covariant relativistic quark-nucleon vertex, we determine $sigma_{coverline{c}}$ under several different scenarios for the magnitude of intrinsic charm (IC) in DIS, namely $langle x rangle_{c+overline{c}} = 0.1%$, $0.35%$, and $1%$, obtaining for these $sigma_{coverline{c}} = 4 pm 4$, $12 pm 13$, and $32 pm 34$ MeV, respectively. These results imply the existence of a reciprocity between the IC parton distribution function (PDF) and $sigma_{coverline{c}}$ such that new information from either DIS or improved determinations of $sigma_{c overline{c}}$ could significantly impact constraints to the charm sector of the proton wave function.
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