未来电子-离子对撞机上的双π⁰产生与广义分布振幅
Di-$π^0$ Production and Generalized Distribution Amplitudes at Future Electron-Ion Colliders
AI总结：
本文提出在未来电子-离子对撞机上通过γ*γ→h₁h₂子过程研究强子广义分布振幅，并利用等效光子近似计算双π⁰产生，表明e-p和e-Au碰撞可获得高于或相当于Belle II的事例率，从而实现高精度检验。
AI中文摘要：
广义分布振幅（GDAs）为强子的三维结构提供了重要见解，描述了从夸克-反夸克对到强子对跃迁所对应的振幅。目前，强子GDAs可以在正负电子对撞中进行探测，其实验可行性已在Belle和BESIII等装置上得到验证。在本研究中，我们提出，强子GDAs也可以在即将建成的电子-离子对撞机（EICs）上通过电子-强子碰撞进行研究，具体通过子过程γ*γ→h₁h₂来实现。在这一框架下，由离子发射的准实光子具有与离子电荷平方成正比的光子通量。因此，我们预期EICs中的截面将显著大于正负电子对撞中的截面。我们采用等效光子近似（EPA）给出了双π⁰产生的数值计算。我们的结果表明，在相同的运动学区域内，EIC上的电子-质子（e-p）碰撞可以产生与Belle II相当的事例率，而电子-金（e-Au）碰撞预计将产生更多的事例。这种提高的事例率有助于在EIC上对双π⁰ GDAs进行高精度检验。
英文摘要：
Generalized distribution amplitudes (GDAs) offer valuable insights into the three-dimensional structure of hadrons, delineating the amplitudes associated with the transition from a quark-antiquark pair to a hadron pair. Currently, hadron GDAs can be probed in electron-positron collisions, with experimental feasibility demonstrated at facilities such as Belle and BESIII. In this study, we put forth the proposition that hadron GDAs can also be investigated in electron-hadron collisions at forthcoming Electron-Ion Colliders (EICs), specifically through the subprocess $γ^*γ\to h_1 h_2$. In this framework, a quasi-real photon, emitted by the ion, exhibits a photon flux proportional to the square of the ion's electric charge. Consequently, we anticipate that the cross sections in EICs will be substantially larger than those in electron-positron collisions. We present numerical calculations pertaining to di-$π^0$ production employing the equivalent photon approximation (EPA). Our findings suggest that, within the same kinematic region, electron-proton ($e$-$p$) collisions at the EIC could yield an event rate comparable to that of Belle II, while electron-gold ($e$-Au) collisions are expected to generate an even greater number of events. This enhanced event rate facilitates a high-precision examination of di-$π^0$ GDAs at the EIC.
