标题： 中间能量重离子碰撞中电场的估算 显示英文标题

标题： Estimation of electric field in intermediate-energy heavy-ion collisions

摘要： 我们估算了中间碰撞能头碰头重离子碰撞中电场的时空分布$\sqrt{s_{\rm NN}} = {\mathcal O}(3 \;-\; 10\;{\rm GeV})$。 利用一个强子级联模型（JAM；Jet AA 微观输运模型），我们数值表明产生的场强度为$eE = {\mathcal O}((30 \;-\; 60\;{\rm MeV})^2)$，这一强度高于QED的施温格极限，并且与强子/QCD尺度相比也非忽略不计，在强子阻止作用下可以持续很长时间$\tau = {\mathcal O}(10\;{\rm fm}/c)$。 我们展示出所产生的场在非微扰意义上非常强，因为非微扰参数（例如Keldysh参数）足够大。 这与高能碰撞$\sqrt{s_{\rm NN}} \gtrsim 100 \;{\rm GeV}$形成对比，高能碰撞中的场存在时间极短，因此是微扰性的。 我们的结果表明电磁场可能对中间能量重离子碰撞中的强子/QCD过程具有现象学影响，并且重离子碰撞可以作为探索非微扰强场物理的新工具。 显示英文摘要

摘要： We estimate the spacetime profile of the electric field in head-on heavy-ion collisions at intermediate collision energies $\sqrt{s_{\rm NN}} = {\mathcal O}(3 \;-\; 10\;{\rm GeV})$. Using a hadronic cascade model (JAM; Jet AA Microscopic transport model), we numerically demonstrate that the produced field has strength $eE = {\mathcal O}((30 \;-\; 60\;{\rm MeV})^2)$, which is supercritical to the Schwinger limit of QED and is non-negligibly large compared even to the hadron/QCD scale, and survives for a long time $\tau = {\mathcal O}(10\;{\rm fm}/c)$ due to the baryon stopping. We show that the produced field is nonperturbatively strong in the sense that the nonperturbativity parameters (e.g., the Keldysh parameter) are sufficiently large. This is in contrast to high-energy collisions $\sqrt{s_{\rm NN}} \gtrsim 100 \;{\rm GeV}$, where the field is extremely short-lived and hence is perturbative. Our results imply that the electromagnetic field may have phenomenological impacts on hadronic/QCD processes in intermediate-energy heavy-ion collisions and that heavy-ion collisions can be used as a new tool to explore strong-field physics in the nonperturbative regime.