Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10/136, A-1040 Vienna, Austria.
Phys Rev Lett. 2012 Nov 9;109(19):192301. doi: 10.1103/PhysRevLett.109.192301. Epub 2012 Nov 7.
Expansion dynamics at the yoctosecond time scale affect the evolution of the quark gluon plasma (QGP) created in heavy ion collisions. We show how these dynamics are accessible through Hanbury Brown-Twiss (HBT) intensity interferometry of direct photons emitted from the interior of the QGP. A detector placed close to the beam axis is particularly sensitive to early polar momentum anisotropies of the QGP. Observing a modification of the HBT signal at the proposed FoCal detector of the LHC ALICE experiment would allow us to measure the isotropization time of the plasma and could provide first experimental evidence for photon double pulses at the yoctosecond time scale.
在皮秒时间尺度上的膨胀动力学影响了在重离子碰撞中产生的夸克胶子等离子体（QGP）的演化。我们展示了如何通过从 QGP 内部发射的直接光子的汉伯里·布朗-特威斯（HBT）强度干涉测量来探测这些动力学。放置在接近束轴的探测器对 QGP 的早期极动量各向异性特别敏感。在 LHC ALICE 实验的 FoCal 探测器中观察到 HBT 信号的这种变化，将使我们能够测量等离子体的各向同性化时间，并为皮秒时间尺度上的光子双脉冲提供第一个实验证据。
