自1977年发现以来，$Ξ(2030)$的自旋-宇称尚未被实验完全确定。最新的粒子数据组（PDG）列表表明它可能是一个$J=5/2$的重子。因此，研究$Ξ(2030)$的质量谱和衰变性质已成为当前确定其自旋-宇称的热点课题。由于三夸克模型无法解释$Ξ(2030)$，我们先前基于其质量谱研究提出它可能是一个主要由$\ar{K}^{}Σ$组成的分子，具有$J^P=5/2^{+}$。为验证其分子态解释，本工作提出研究$Ξ(2030)$的强衰变，假设它是一个主要由$\ar{K}^{}Σ$组成的$P$-波$J^P=5/2^{+}$介子-重子分子。我们计算了$Ξ(2030)$所有实验测量的两体和三体末态衰变宽度，包括$Ξ(2030) \ o \ar{K}Λ, \ar{K}Σ, πΞ, πΞ^{*}$和$Ξ(2030) \ o ππΞ, π\ar{K}Σ, π\ar{K}Λ$。结果表明，总衰变宽度和分宽度在误差范围内与实验值吻合良好。这支持$Ξ(2030)$是一个自旋-宇称$J^P = 5/2^{+}$、主要由$\ar{K}^{*}Σ$组成的分子。与实验中心值相比，我们的结果略小，这表明$Ξ(2030)$可能包含除介子-重子分子成分外的额外成分，例如三夸克结构。
英文摘要：
Since its discovery in 1977, the spin-parity of $Ξ(2030)$ has not been fully determined experimentally. The latest Particle Data Group (PDG) listing suggests it may be a baryon with $J=5/2$. Therefore, studying the mass spectrum and decay properties of $Ξ(2030)$ has become a current hot topic to definitively establish its spin-parity. As the three-quark model fails to explain $Ξ(2030)$, we previously proposed it may be a molecule primarily composed of $\bar{K}^{}Σ$ with $J^P=5/2^{+}$, based on its mass spectrum study. To verify its molecular state interpretation, this work proposes studying the strong decays of $Ξ(2030)$ assuming it is a $P$-wave $J^P=5/2^{+}$ meson-baryon molecule predominantly composed of $\bar{K}^{}Σ$. We calculated all experimentally measured two-body and three-body final state decay widths of $Ξ(2030)$, including $Ξ(2030) \to \bar{K}Λ, \bar{K}Σ, πΞ, πΞ^{*}$, and $Ξ(2030) \to ππΞ, π\bar{K}Σ, π\bar{K}Λ$. The results indicate that both the total decay width and partial decay widths agree well with experimental values within the error margins. This supports that $Ξ(2030)$ is a molecule with spin-parity $J^P = 5/2^{+}$, predominantly composed of $\bar{K}^{*}Σ$. Compared to the experimental central values, our results are slightly smaller, which suggests that $Ξ(2030)$ may contain additional components besides meson-baryon molecular components, such as three quark structures.
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Studying the Triple Higgs Self-Coupling Via e+e- --> b bar b HH, t bar t HH at Future Linear e+e- Colliders
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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）
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Implication of the observed $ψ(3770)\to p\bar{p}π^0$ for studying the $p\bar{p}\to ψ(3770)π^0$ process
Lanzhou University（兰州大学）；Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所）；School of Physical Science and Technology, Lanzhou University（兰州大学物理科学与技术学院）；Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）
LEP上明显过量的$Z \rightarrow b \bar b$事件可能是标准模型之外的新物理的指示。然而，无论是在双希格斯偶态模型还是最小超对称标准模型中，任何解释都会导致顶夸克的一种重要的新衰变模式，并抑制$t \rightarrow W b$分支分数，这与在Tevatron上观察到的情况相反。在双希格斯模型中，$Z \rightarrow b \bar b$ +一个主要衰变为$b \bar b$的轻玻色子的分支分数至少是$^{-4}$的10阶。
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Improved method for CKM constraints in charmless three-body B and B_s decays
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Many decays of light baryons consisting of light $u,d,s$ quarks have been measured, and these measurements will help us to understand the decay properties of light baryons. In this work, we study two-body nonleptonic weak decays of light baryon octet $(T_8)$ and baryon decuplet $(T_{10})$ by the topological diagram approach (TDA) under the SU(3) flavor symmetry for the first time. We find that (1) the TDA and the SU(3) irreducible representation approach (IRA) match consistently in $T_{10}\to T^{(')}_{8,10}P_8$ ($P_8$ is the light pseudoscalar meson octet); (2) almost all relevant not-yet-meas…
Vectorlike fermions are an important target for hadron collider searches. We show that the vectorlike quarks may predominantly decay via higher-dimensional operators into a quark plus a couple of other Standard Model fermions. Pair production of vectorlike quarks of charge 2/3 at the LHC would then lead to a variety of possible final states, including $t\bar t + 4τ$, $t\bar bν+ 3τ$, $t\bar t + 4μ$, $t\bar bν+ 3μ$ or $t\bar t + 4b$. Additional channels ($b\bar b + 4τ$, $6b$, etc.) arise in the case of a vectorlike quark of charge $-1/3$. If the vectorlike quark decays into three light quarks, t…
Determining the Quantum Numbers of Simplified Models in $t\bar{t}X$ production at the LHC
简化的模型为表征和探索大类紫外线理论的新物理学提供了一条途径。在本文中，我们研究了大型强子对撞机探测新型光共振$X$的自旋和宇称量子数的能力，该共振主要通过$t\bar t X$通道与各种简化模型中的第三代夸克耦合。在评估了大型强子对撞机发现$X$的潜力后，我们提出了几个对新共振的自旋和CP性质敏感的运动学变量。我们展示了如何利用半轻子通道中的微分分布的分析可以区分各种可能性。我们发现，从赝标量或（轴向）矢量的潜在的歧视是特别有前途的标量。
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Truncating the low-lying modes of the lattice Dirac operator results in an emergence of the chiral-spin symmetry $SU(2)_{CS}$ and its flavor extension $SU(2N_F)$ in hadrons. These are symmetries of the quark - chromo-electric interaction and include chiral symmetries as subgroups. Hence the quark - chromo-magnetic interaction, which breaks both symmetries, is located at least predominantly in the near - zero modes. Using as a tool the expansion of propagators into eigenmodes of the Dirac operator we here analytically study effects of a gap in the eigenmode spectrum on baryon correlators. We fi…
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The charmoniumlike state $Y(4260)$ is described as predominantly a $D_1 \bar{D}$ molecule in a coupled-channel quark model [Phys.\,Rev.\,D\,\textbf{96},\,114022\,(2017)]. The heavy quark spin symmetry (HQSS) thus implies the possible emergence of its heavy quark spin partners with molecular configuration as $D_1 \bar{D}^*$ and $D_2^* \bar{D}^*$ below these charmed mesons' thresholds. We analyze the probabilities of various intermediate charmed meson loops for $J^{PC}=1^{--}$ exotic state $Y(4360)$ and find that the channel $D_1 \bar{D}^*$ couples more strongly around its mass regime, and the c…
