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arXiv 2303.09581hep-phhep-exhep-latnucl-exnucl-th
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矢量介子在代数模型中的光前波函数

Light-front Wave Functions of Vector Mesons in an Algebraic Model

B. Almeida-Zamora, J. J. Cobos-Martínez, A. Bashir, K. Raya, J. Rodríguez-Quintero, J. Segovia

AI总结:

本文首次将代数模型扩展至矢量介子,计算了ρ、φ、J/ψ和Υ(1S)的领先扭度光前波函数,揭示了轻与重矢量介子在谱密度和波函数形状上的显著差异。

摘要:

受最近一个代数模型发展的启发,该模型为最低态赝标量介子(既包括轻夸克扇区也包括重夸克扇区)的内部结构提供了充分且统一的描述,我们首次将其扩展到矢量介子情形。该代数模型通过出现在协变夸克-反夸克束缚态振幅(即Bethe-Salpeter振幅)的Nakanishi积分表示中的谱密度函数来描述介子结构。我们通过它们与部分子分布振幅的联系,计算了ρ(770)、φ(1020)、J/ψ和Υ(1S)介子的领先扭度光前波函数。在我们呈现的结果中,以下内容特别值得关注:(i)横向光前波函数可以从相应的部分子分布振幅代数地获得,而纵向光前波函数则并非如此,后者需要一个中间步骤,即必须从特定的部分子分布振幅推导出谱密度函数;(ii)推导出的谱密度函数在轻矢量介子和重矢量介子之间显示出显著差异,后者比前者更窄;这些函数也不是正定的,尽管整个曲线上的积分大于零,正如预期的那样;(iii)具有轻夸克成分的矢量介子的纵向和横向光前波函数表现出陡峭的x和p⊥²依赖性,而J/ψ和Υ(1S)介子的光前波函数则其特征在于在x范围内分布狭窄,但相对而言,在所描绘的p⊥²范围内衰减要平缓得多。

英文摘要:

Inspired by the recent development of an algebraic model which provides an adequate and unified description of the internal structure of the lowest-lying pseudo-scalar mesons, belonging both to the light quarks sector and to the one of heavy quarks, we perform its first extension to the vector-meson case. The algebraic model describes meson's structure in terms of the spectral density function that appears in a Nakanishi integral representation of the covariant quark-antiquark bound-state amplitude, \emph{i.e.}, the Bethe-Salpeter amplitude. We compute the leading-twist light-front wave functions of the $ρ(770)$, $ϕ(1020)$, $J/ψ$ and $Υ(1S)$ mesons through their connection with the parton distribution amplitudes. Among the results we present, the following are of particular interest: (i) transverse light-front wave functions can be obtained algebraically from the corresponding parton distribution amplitudes, whereas that is not the case for longitudinal light-front wave functions, which requires an intermediate step where a spectral density function must be derived from the particular parton distribution amplitude; (ii) the derived spectral density functions show marked differences between light and heavy vector mesons, the latter being narrower as compared to the former; these are also non-positive definite, although the integral over the entire curve is larger than zero as expected; and (iii) the longitudinal and transverse light-front wave functions of vector mesons with light quark content exhibit steep $x$- and $p_\perp^2$-dependence, while those of the $J/ψ$ and $Υ(1S)$ mesons are characterized by narrow distributions in the $x$-range but, comparatively, much more gradual fall-offs with respect to the $p_\perp^2$-range depicted.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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