论文标题
手性扰动理论中核子散射的前向双重康普顿散射：减去函数和非极化结构函数的力矩
Forward doubly-virtual Compton scattering off the nucleon in chiral perturbation theory: the subtraction function and moments of unpolarized structure functions
论文作者
论文摘要
核子上的前向双重康普顿散射（VVC）包含有关核子结构的大量信息，与原子光谱和电子散射中两光子交换效应的计算有关。我们报告了手性扰动理论中低能VVC（$χ$ pt）的完整近级领先阶（NLO）计算。在这里，我们专注于未铝的VVCS振幅$ T_1（ν，Q^2）$和$ T_2（ν，Q^2）$，以及相应的结构功能$ f_1（x，q^2）$和$ f_2（x，x，q^2）$。在可能的情况下，我们的结果与低能结构量（例如核子极化能力）的“数据驱动”分散评估面临。我们发现，在非常低的动量转移$ Q $的情况下，分散评估有重大分歧；例如，在零动量转移的极化性斜率中。通过扩大逆核质量质量的能力的结果，我们重现了已知的“重 - 巴里昂”表达式。这是对我们计算的检查，并证明了明显的Lorentz-Invariant（B $χ$ PT）和重型 - 巴里昂（HB $χ$ PT）框架之间的差异。
The forward doubly-virtual Compton scattering (VVCS) off the nucleon contains a wealth of information on nucleon structure, relevant to the calculation of the two-photon-exchange effects in atomic spectroscopy and electron scattering. We report on a complete next-to-leading-order (NLO) calculation of low-energy VVCS in chiral perturbation theory ($χ$PT). Here we focus on the unpolarized VVCS amplitudes $T_1(ν, Q^2)$ and $T_2(ν, Q^2)$, and the corresponding structure functions $F_1(x, Q^2)$ and $F_2(x,Q^2)$. Our results are confronted, where possible, with "data-driven" dispersive evaluations of low-energy structure quantities, such as nucleon polarizabilities. We find significant disagreements with dispersive evaluations at very low momentum-transfer $Q$; for example, in the slope of polarizabilities at zero momentum-transfer. By expanding the results in powers of the inverse nucleon mass, we reproduce the known "heavy-baryon" expressions. This serves as a check of our calculation, as well as demonstrates the differences between the manifestly Lorentz-invariant (B$χ$PT) and heavy-baryon (HB$χ$PT) frameworks.
