论文标题
在$ \ sqrt {s} = 200 $ gev in Rhic-star的$λ（\barλ）$ hyperon $λ（\barλ）$ hyperon的纵向旋转转移的测量
Measurement of longitudinal spin transfer of the $Λ(\barΛ)$ hyperon in polarized p+p collisions at $\sqrt{s}=200$ GeV at RHIC-STAR
论文作者
论文摘要
由于EMC实验在1980年代后期对质子的自旋结构的第一个令人惊讶的结果以来，在理解质子自旋的起源方面取得了很多进展。但是，海夸克对质子旋转的贡献，例如，奇怪的夸克（反夸克）的螺旋分布，$ s（\ bar {s}）$，仍然受到实验数据的约束。 Since the $s(\bar{s})$ is expected to carry a substantial fraction of the spin of the $Λ(\barΛ)$ hyperon, measurements of the longitudinal spin transfer, $D_{LL}$, of the $Λ(\barΛ$) hyperon can thus shed light on the helicity distribution of the $s(\bar{s})$ and the longitudinally polarized fragmentation功能。在这些程序中，我们将使用2015年RHIC-Star收集的数据（pseudo-rapities $ |η|）介绍$λ（\barλ$）$ d_ {ll} $分析的状态。 <1.2 $和横向动量高达$ 8.0 $ gev $/c $。还研究了$ d_ {ll} $作为$λ（\barλ）$ hyperon的纵向动量分数的函数。该数据集大约是用于先前发布的$ d_ {ll} $结果的2009年数据的两倍。
Since the first surprising results on the spin structure of the proton by the EMC experiment in the late 1980s, much progress has been made in understanding the origin of the proton spin. However, the sea quark contribution to the proton spin, for example, the helicity distributions of the strange quark (anti-quark), $s(\bar{s})$, is still not well constrained by experimental data. Since the $s(\bar{s})$ is expected to carry a substantial fraction of the spin of the $Λ(\barΛ)$ hyperon, measurements of the longitudinal spin transfer, $D_{LL}$, of the $Λ(\barΛ$) hyperon can thus shed light on the helicity distribution of the $s(\bar{s})$ and the longitudinally polarized fragmentation functions. In these proceedings, we will present the status of the $Λ(\barΛ$) $D_{LL}$ analysis using data collected at RHIC-STAR in 2015, for the pseudo-rapidity $|η| < 1.2$ and transverse momenta up to $8.0$ GeV$/c$. The $D_{LL}$ as a function of the longitudinal momentum fraction of the $Λ(\barΛ)$ hyperon in the jet is also investigated. This data set is about twice as large as the 2009 data used for the previously published $D_{LL}$ results.
