论文标题
重型离子碰撞中的自旋极化和对齐
Spin polarization and alignment in heavy-ion collisions
论文作者
论文摘要
我们报告了来自Fair，RHIC和LHC Energies的超子（$p_λ$）全局自旋极化的测量值。 $p_λ$继续遵循$ \ sqrt {s _ {\ mathrm nn}} $ <7.7 GEV的趋势越来越大，表明即使在Hadronic主导区域中，巨大的涡旋也普遍存在。 Isobar碰撞的局部自旋极化（$ p_ {z，2} $）的新测量遵循与以前的RHIC和LHC能量相同的模式。可观察到的可观察到的是由预测的Baryonic旋转厅效应，净局部极化（$ p_ {z，2}^{\ mathrm {net}} $），在$ \ sqrt {s _ {\ athrm nn}} $ = 19.6 $ = 19.6和27 gev中显示了au+au碰撞中的负值。第一个$ p_ {z} $测量相对于200 GEV RHIC ISOBAR碰撞中的三阶谐波的测量显示了非零的正弦调制，表明介质中存在复杂的涡旋结构。令人惊讶的是各种向量介子（$ k^{*0} $，$ k^{*0} $，$ k^{*\ pm} $，$ ϕ $和$队汇和$ j/ψ$）的旋转对齐方式（$ρ_{00} $）令人惊讶。几种物种的$ρ_{00} $中的大偏差对该理论构成了挑战。
We report the measurements of global spin polarization of hyperons ($P_Λ$) from FAIR, RHIC and LHC energies. The $P_Λ$ continue to follow an increasing trend at $\sqrt{s_{\mathrm NN}}$ < 7.7 GeV indicating that enormous vorticity prevail even in hadronic dominant region. New measurements of local spin polarization ($P_{z,2}$) from isobar collisions follow the same pattern observed in previous RHIC and LHC energies. An observable motivated by predicted baryonic Spin Hall Effect, the net local polarization ($P_{z,2}^{\mathrm{net}}$), shows negative value in Au+Au collisions at $\sqrt{s_{\mathrm NN}}$ = 19.6 and 27 GeV. The first $P_{z}$ measurement with respect to third order harmonic in 200 GeV RHIC isobar collisions show a non-zero sine modulation, indicating the presence of complex vortical structure in the medium. Surprising new patterns of spin alignment ($ρ_{00}$) for various vector mesons ($K^{*0}$, $K^{*\pm}$, $ϕ$ and $J/ψ$) emerged at both RHIC and LHC energies. The large deviation in $ρ_{00}$ of several species poses challenge to the theory.
