Heavy quark currents in ultra-high energy neutrino interactions

TL;DR

This paper analyzes heavy quark effects in ultra-high energy neutrino interactions, revealing a strong left-right asymmetry and providing simplified formulas for structure functions using gluon density, with implications for cross section calculations.

Contribution

It introduces a detailed analysis of heavy quark contributions, deriving practical formulas for structure functions and highlighting the dominance of certain components at ultra-high energies.

Findings

$F_L$ significantly exceeds $F_R$, leading to $xF_3 oughly F_T$.

The scalar component $F_S$ dominates the structure function $F_2$ at low $Q^2$, with a hierarchy $F_S \\gg F_L \\gg F_R$.

The total cross section is evaluated within the color dipole BFKL formalism.

Abstract

We discuss heavy quark contributions to the neutrino-nucleon total cross section at very high energies, well above the real top production threshold. The top-bottom weak current is found to generate strong left-right asymmetry of neutrino-nucleon interactions. We separate contributions of different helicity states and make use of the $\bkappa$-factorization to derive simple and practically useful formulas for the left-handed ($F_L$) and right-handed ($F_R$) components of the conventional structure function $2xF_3=F_L-F_R$ in terms of the integrated gluon density. We show that $F_L\gg F_R$ and, consequently, $xF_3\approx F_T$, where $F_T$ is the transverse structure function. The conventional structure function $F_2=F_S+F_T$ at $Q^2\ll m_t^2$ appears to be dominated by its scalar (also known as longitudinal) component $F_S$ and the hierarchy $F_S\gg F_L\gg F_R$ arises naturally. We evaluate the total neutrino-nucleon cross section at ultra-high energies within the color dipole BFKL formalism.