论文标题
$λ$（$ \barλ$）的全球和本地两极化在LHC的Alice的PB-PB碰撞中
Global and local polarization of $Λ$ ($\barΛ$) hyperons in Pb--Pb collisions in ALICE at the LHC
论文作者
论文摘要
$λ$和$ \ \barλ$ hyperons（$ p _ {\ rm h} $）的全球两极分化已在$ \ snn = $ \ snn = $ 2.76 TEV和5.02 TEV中测量的Alice在大型Hadron Collider（LHC）中。在两个碰撞能量下，超子全局极化与零一致。 $λ$和$ \ \barλ$ hyperons的本地两极化沿梁（$ z $）方向，$ p _ {\ rm z} $，也已在$ \ snn = 5.02 $ tev的pb-pb碰撞中测量。 $ p _ {\ rm z} $，根据第二个谐波对称平面的超子发射角的函数，表现出第二个谐波正弦调制，如椭圆流所致。据报道，不同碰撞中心的全球和局部超子极化的测量值是在半个碰撞中的横向动量的函数。这些结果显示了LHC处的Pb-pb碰撞中的非零超子$ p _ {\ rm z} $的第一个实验证据。
The global polarization of the $Λ$ and $\barΛ$ hyperons ($P_{\rm H}$) has been measured in Pb--Pb collisions at $\sNN=$ 2.76 TeV and 5.02 TeV in ALICE at the Large Hadron Collider (LHC). The hyperon global polarization is found to be consistent with zero at both collision energies. The local polarization of the $Λ$ and $\barΛ$ hyperons along the beam ($z$) direction, $P_{\rm z}$, has also been measured in Pb--Pb collisions at $\sNN=5.02$ TeV. The $P_{\rm z}$, measured as a function of the hyperon emission angle relative to the second harmonic symmetry plane, exhibits a second harmonic sine modulation, as expected due to elliptic flow. The measurements of global and local hyperon polarization are reported for different collision centralities and as a function of transverse momentum in semicentral collisions. These results show the first experimental evidence of a non-zero hyperon $P_{\rm z}$ in Pb--Pb collisions at the LHC.
