Latest measurements of $ΔηΔφ$ correlations of identified particles show differences in particle production between baryons and mesons. The correlation functions for mesons exhibit the expected peak dominated by effects of mini-jet fragmentation and are reproduced well by general purpose Monte Carlo generators. For baryon pairs (where both particles have the same baryon number) a surprising near-side anti-correlation structure is observed instead of a peak, implying that two such particles are rarely produced with similar momentum. These results present a challenge to the contemporary models and there is no definite theoretical explanation of the observation. In this proceedings an overview of the latest baryon correlation measurements yielding startling results are presented.
Factorization and angular distribution asymmetries in charmful baryonic B decays
我们检验了广义因式分解方法的有效性,并计算了$\bar B^0\to Λ\bar p D^{(*)+}$中有趣的三体重子衰变的角关联。利用从重子$B$衰变中提取的类时重子形状因子,我们得到了与BELLE合作组最近的数据相一致的${\cal B}(\bar B^0\to Λ\bar p D^+,Λ\bar p D^{*+})=(1.85\pm 0.30,2.75\pm 0.24)\times 10^{-5}$,这表明基于因子分解的理论方法仍然有效.对于角分布的不对称性,我们发现${\cal A}_θ(\bar B^0\to Λ\bar p D^+,Λ\bar p D^{*+})=(-0.030\pm 0.002\,,+0.150\pm 0.000)$,这是与目前的测量一致。此外,我们预测,${\cal A}_θ(\bar B^0\to p\bar p D^{0},p\bar p D^{*0})=+0.04\pm 0.01$ .未来在BELLE和LHCb以及super-BELLE上对这些角关联的精确探索对于证明目前在迷人的三体重子衰变中的因式分解方法是重要的。
Analysis of angular distribution asymmetries and the associated $C\!P$ asymmetries in three-body decays of bottom baryons
我们引入了一组代表角分布不对称性的观测量,它可以被看作是角分布的前后不对称性的推广,可以作为一种有效的工具来寻找底重子和粲重子三体衰变中的$C\!P$破坏.我们建议在(1)包含$Λ^0$、$Σ^\pm$或$Λ_c^+$的衰变(如$Λ_b\to Λ^0 D$和$Λ_b\toΛ^0ρ(770)^0$)和(2)包含相反宇称中间共振的底重子三体衰变中寻找这种$C\!P$不对称性。典型的例子包括$Ξ_b^-\to p K^- K^-$、$Λ_b^0\to p K_Sπ^-$和$Λ_b^0\to p π^0π^-$,其中最后一个衰变通道被用作玩具模型来说明基本思想。
Searching for $C\!P$ violation through two-dimensional angular distributions in four-body decays of bottom and charmed baryons
本文提出通过底强子和粲强子四体衰变中的二重角分布来寻找$C\!P$破坏。二重角分布中的两个极角是相关的,中间共振的干涉是其中的一个重要来源。这些干涉将在二重角分布中留下轨迹,利用这些轨迹可以研究$C\!P$破坏。特别注意的情况下,所有的中间共振是不同的,这是唯一的四体衰变。建议通过对二次角分布的分析来寻找类似$Λ_b^0\to p π^-π^+π^-$的四体衰变中的$C\!P$破坏。本文提出的方法也可广泛应用于其它四体衰变过程。
Studying strangeness and baryon production mechanisms through angular correlations between charged $Ξ$ baryons and identified hadrons in pp collisions at $\sqrt{s}$ = 13 TeV
本文利用 ALICE 探测器在 $\sqrt{s}=13$ TeV pp 碰撞中测量带电 $Ξ$ 重子与已鉴别强子的角关联,研究了奇异性与重子产生机制,发现现有 Monte Carlo 模型均无法完全描述数据,为产生机制提供了严格约束。
Studying baryon number transport dynamics via hyperon-kaon correlations in $p + \mathrm{Au}$ collisions at $\sqrt{s_{_{\rm NN}}}=20$, $39$ and $62$ GeV
Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), Fudan University(核物理与离子束应用教育部重点实验室,复旦大学)
Studying charm hadronisation into baryons with azimuthal correlations of $Λ_{\rm c}^{+}$ with charged particles in pp collisions at $\mathbf{\sqrt{\it s} = 13}$ TeV
本研究利用ALICE探测器在13 TeV pp碰撞中首次测量$Λ_{\rm c}^{+}$重子与带电粒子的方位角关联,发现其关联低动量粒子多于D介子,且蒙特卡洛模型无法预测,暗示粲重子产生时强子化过程可能不同。
Insight into particle production mechanisms via angular correlations of identified particles measured with ALICE in pp collisions at $\mathbf{\sqrt{\textit s}}=7$ TeV