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We demonstrate that a nonzero strangeness contribution to the spacelikeelectromagnetic form factor of the nucleon is evidence for astrange-antistrange asymmetry in the nucleon's light-front wave function, thusimplying different nonperturbative contributions to the strange and antistrangequark distribution functions. A recent lattice QCD calculation of the nucleonstrange quark form factor predicts that the strange quark distribution is morecentralized in coordinate space than the antistrange quark distribution, andthus the strange quark distribution is more spread out in light-front momentumspace. We show that the lattice prediction implies that the difference betweenthe strange and antistrange parton distribution functions, $s(x)-\bar{s}(x)$,is negative at small-$x$ and positive at large-$x$. We also evaluate thestrange quark form factor and $s(x)-\bar{s}(x)$ using a baryon-mesonfluctuation model and a novel nonperturbative model based on light-frontholographic QCD. This procedure leads to a Veneziano-like expression of theform factor, which depends exclusively on the twist of the hadron and theproperties of the Regge trajectory of the vector meson which couples to thequark current in the hadron. The holographic structure of the model allows usto introduce unambiguously quark masses in the form factors and quarkdistributions preserving the hard scattering counting rule at large-$Q^2$ andthe inclusive counting rule at large-$x$. Quark masses modify the Reggeintercept which governs the small-$x$ behavior of quark distributions,therefore modifying their small-$x$ singular behavior. Both nonperturbativeapproaches provide descriptions of the strange-antistrange asymmetry andintrinsic strangeness in the nucleon consistent with the lattice QCD result.

Nonperturbative strange-quark sea from lattice QCD, light-front holography, and meson-baryon fluctuation models