标题： 精确的$Z^2$标度在重离子碰撞的高能极限中的对产生 显示英文标题

标题： Exact $Z^2$ scaling of pair production in the high-energy limit of heavy-ion collisions

摘要： 两中心狄拉克方程在两个碰撞的重离子外部电磁场中，当离子以光速运动时被精确求解，得到了自由电子-正电子对产生的非微扰振幅。 我们找到了该解在大但有限碰撞能量下的适用条件，并用它来解释最近的实验结果。 观测到的正电子产率与入射粒子和靶核电荷的平方成比例，这是非微扰电荷依赖性的精确抵消的结果，并且在大耦合情况下也成立。 其他可观测量会对非微扰相位敏感。 显示英文摘要

摘要： The two-center Dirac equation for an electron in the external electromagnetic field of two colliding heavy ions in the limit in which the ions are moving at the speed of light is exactly solved and nonperturbative amplitudes for free electron-positron pair production are obtained. We find the condition for the applicability of this solution for large but finite collision energy, and use it to explain recent experimental results. The observed scaling of positron yields as the square of the projectile and target charges is a result of an exact cancellation of a nonperturbative charge dependence and holds as well for large coupling. Other observables would be sensitive to nonperturbative phases.