In this study, we try to extract $ωn$, $ωp$ and $ϕ$N scattering lengths from the differential cross-section data of near-threshold $ω$ and $ϕ$ photoproductions not only to the energy at threshold t$_{thr}$, but also in t to t = 0. The incoherent data of $ω$ and $ϕ$ photoproductions on deuterium target for scattering length extractions are provided by CBELSA/TAPS Collaboration and LEPS Collaboration respectively, where the deuteron is usually approximated as a weakly bound state of a quasi-free neutron plus a quasi-free proton. Under the Vector Meson Doninance model and the assumption of energy independence of the differential cross-section, we obtained the $|α_{ωn^{*}}|$ and $|α_{ωp^{*}}|$ of loosely bound neutron and proton in the deuteron to be 0.709 $\pm$ 0.078 fm and 0.621 $\pm$ 0.022 fm respectively at threshold t$_{thr}$ (1.258 $\pm$ 0.130 fm and 1.056 $\pm$ 0.032 fm respectively in t to t = 0) for the first time by fitting the near-threshold data of $γ$d $\rightarrow$ $ω$n(p) and $γ$d $\rightarrow$ $ω$p(n). For a comparison study, we also extracted the scattering length $|α_{ωp}|$ of the free proton from the $ω$ photoproduction on the hydrogen target by CBELSA/TAPS Collaboration. With the near-threshold and incoherent $ϕ$ photoproduction data of $γ$d $\rightarrow$ $ϕ$pn by LEPS Collaboration, we obtained scattering length $|α_{ϕN}|$ of the bound nucleon inside the deuteron to be 0.109 $\pm$ 0.008 fm at threshold t$_{thr}$ and 0.276 $\pm$ 0.010 fm in t to t = 0, respectively. The obtained $|α_{ωp}|$ and $|α_{ϕN}|$ are basically in agreement with the experimental indications and the theoretical predictions within the current uncertainties.
$J/ψN$ photoproduction on deuterium as a test for exotic baryons
我们扩展了以前的研究光生奇异重子共振的反应$γ+ d \to J/ψ+ n + p$,它允许同时调查的反应$γ+ p \to P_c^+ \to J/ψ~p$ \hbox{($n$ spectator)}和$γ+ n \to P_c^0 \to J/ψ~n$ \hbox{($p$ spectator).}这里$P_c^+$是一个奇异的重子与夸克内容$c \bar c uud$,和$P_c^0$是它的假设的同位旋伙伴与夸克内容$c \bar c ddu$。我们发现:如果$J/ψ~n$光生过程由与$c\bar c$对的光子耦合主导,则\hbox{(1) The}光生过程的横截面应等于$J/ψ~p$光生过程的横截面。在这种情况下,这两个过程通过同位旋反射是相等的。(2)如果一个$P_c^+$候选者是真正的$c \bar c u u d$共振,它的同位旋伙伴$P_c^0 = c \bar c d d u$应该具有相同的质量(同样通过同位旋反射)。(3)在没有费米运动的情况下,从氘核光生$P_c$的截面应该接近两个相等截面之和:$σ(γp \to P_c^+)$(旁观者$n$)和$σ(γn \to P_c^0)$(旁观者$p$)。(4)费米运动的影响是显著的。它们包括涂抹、形状因子抑制和外壳脱落。结果是共振明显更宽,并且氘的峰值截面预计将大大小于$γp$的两倍。
K0 photoproduction on the deuteron and the extraction of the elementary amplitude
研究了氘核上光生K_0的过程,包括YN和KN终态相互作用(FSI),以及π介子介导的γ d --> pi NN --> KYN过程。在阈值区,内含截面的YN再散射效应较大。极化观测值在较大的K介子和超子角下显示出相当大的FSI效应。结果表明,在FSI效应可以忽略的准自由散射区,提取基元γ N -> KY振幅是可能的。此外,在该区域中的截面是大的,表明在该运动学区域中的测量是有利的。
First Extraction of the $ϕ$-$^{4}\mathrm{He}$ scattering length from near-threshold $ϕ$ photoproduction on helium-4
Institute of Modern Physics, Chinese Academy of Sciences(中国科学院近代物理研究所);School of Nuclear Science and Technology, University of Chinese Academy of Sciences(中国科学院大学核科学与技术学院);State Key Laboratory of Heavy Ion Science and Technology, Institute of Modern Physics, Chinese Academy of Sciences(中国科学院近代物理研究所重离子科学和技术国家重点实验室)
On the Extraction of Cross Sections for pi0 and eta Photoproduction off Neutrons from Deuteron Data
本文讨论了从氘核数据中提取中性赝标介子离中子光生截面的过程。主要的陈述是,质子和中子靶的末态相互作用(FSI)修正通常是不相等的,但对于π 0的产生,有一些特殊情况,它们必须是相同的,并且在入射光子能量和π极角θ^* 的参数空间中有很大的区域,它们碰巧非常相似。由于这种激发的特定的同位旋结构,在Delta(1232)3/2+共振的能量范围内,对于$π_0$的产生,对两个靶核子的校正实际上是相同的。同样在$Δ$ -等压线范围以上,质子和中子修正因子之间的大差异仅在极端前向角($θ^*$ < 20度)下预测,但结果在较大角下相似。讨论了gp-> pi 0 p和gn-> pi 0 n修正因子的数值结果。并给出了gd--> pi 0 pn截面的模型描述。
Mechanisms of high energy polarized photoproduction of $π^{-}Δ^{++}$
Center for Exploration of Energy and Matter, Indiana University(印第安纳大学能量与物质探索中心);Department of Physics, Indiana University(印第安纳大学物理系);AGH University of Krakow, Faculty of Physics and Applied Computer Science(克拉科夫AGH科技大学物理与应用计算机科学学院);Departament de Física Quàntica i Astrofísica and Institut de Ciències del Cosmos, Universitat de Barcelona(巴塞罗那大学量子天体物理学系与宇宙科学研究所);Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina(墨西拿大学数学、信息学、物理与地球科学系);INFN Sezione di Catania(意大利国家核物理研究所卡塔尼亚分部);Departamento de Física Interdisciplinar, Universidad Nacional de Educación a Distancia (UNED)(西班牙国立远程教育大学跨学科物理系);Center for Theoretical Physics - A Leinweber Institute, Massachusetts Institute of Technology(麻省理工学院莱因韦伯理论物理中心);Theory Center, Thomas Jefferson National Accelerator Facility(托马斯·杰斐逊国家加速器设施理论中心);Department of Physics, Old Dominion University(老道明大学物理系)
Extraction of Meson Resonances from Three-pions Photo-production Reactions
我们研究了从核子上的三π介子光生反应的Dalitz图分析中提取的介子共振性质的模型依赖性。在Phys. Rev. D 84,114019(2011)中开发的酉模型中,我们生成Dalitz图分布作为数据来执行同量异位素模型拟合,这与之前对三π介子产生反应的大多数分析相似。结果表明,两种模型的共振位置吻合较好,但在分叉点附近存在共振极点。从这两个模型中提取的共振振幅的残差和通常的Breit-Wigner程序只对窄宽度的孤立共振一致。对于重叠共振,大多数提取的残留物可能完全不同。我们的研究结果表明,即使有高精度的数据,共振提取应该是基于模型的振幅参数化的三粒子么正性条件的约束。
The Nucleon Axial Form Factor from Elementary Target Data
Lawrence Livermore National Laboratory(劳伦斯利弗莫尔国家实验室);York University(约克大学);University of Rochester(罗切斯特大学);SLAC National Accelerator Laboratory(斯坦福直线加速器中心);Stanford University(斯坦福大学);Aligarh Muslim University(阿里加尔穆斯林大学);William & Mary(威廉与玛丽学院);Fermi National Accelerator Laboratory(费米国家加速器实验室);University of California at Davis(加州大学戴维斯分校);Centro Brasileiro de Pesquisas Físicas(巴西物理研究中心)
Physics-Informed Global Extraction of the Universal Small-$x$ Dipole Amplitude
Central China Normal University(华中师范大学);Institute of Particle Physics, Central China Normal University(华中师范大学粒子物理研究所);Artificial Intelligence and Computational Physics Research Center, Central China Normal University(华中师范大学人工智能与计算物理研究中心);Fudan University(复旦大学);Institute of Modern Physics, Fudan University(复旦大学现代物理研究所);Shanghai Research Center for Theoretical Nuclear Physics, NSFC and Fudan University(上海理论核物理中心(国家自然科学基金委与复旦大学));Shandong University(山东大学)