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arXiv 1008.4422nucl-th
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氘靶非相干光生φ的理论研究

Theoretical study of incoherent phi photoproduction on a deuteron target

Takayasu Sekihara, Alberto Martinez Torres, Daisuke Jido, Eulogio Oset

摘要:

我们研究了氘核中的光生π介子,注意到从束缚质子到自由质子的截面的修正,目的是与LEPS的最新结果进行比较。为了这个目的,我们考虑费米运动的单次散射和再散射的φ占φ吸收的第二个核子,以及再散射的质子。我们发现,双散射的贡献是远远小于典型的截面的γ p到φ p在自由空间中,这意味着一个非常小的屏蔽在氘核中的φ生产。另一方面,从质子再散射的贡献,被发现是不可忽略的相比,在自由空间中的γ p到φ p的截面,并导致一个适度的减少的φ光生截面上的氘核在前进的角度,如果LEPS设置被考虑在内。费米运动允许在自由情况下相空间禁止的区域中的单次散射的贡献。特别是,我们发现,为转移的动量平方接近最大值,费米运动的急剧变化的形状的d σ/ dt,到这一点的比,这个截面的自由一个变得非常敏感的t的精确值选择,或在实验分析中使用的箱的大小。因此,t的这个特定区域似乎并不最适合发现氘核中可能的φ吸收效应。该反应的理论研究作为一个函数的t和实验的角切割在LEPS的效果进行了讨论,为今后的实验分析的反应提供了指导方针。

英文摘要:

We study the photoproduction of phi mesons in deuteron, paying attention to the modification of the cross section from bound protons to the free ones with the aim of comparing with recent results at LEPS. For this purpose we take into account Fermi motion in single scattering and rescattering of the phi to account for phi absorption on a second nucleon as well as the rescattering of the proton. We find that the contribution of the double scattering is much smaller than the typical cross section of gamma p to phi p in free space, which implies a very small screening of the phi production in deuteron. The contribution from the proton rescattering, on the other hand, is found to be not negligible compared to the cross section of gamma p to phi p in free space, and leads to a moderate reduction of the phi photoproduction cross section on a deuteron at forward angles if LEPS set up is taken into account. The Fermi motion allows contribution of the single scattering in regions forbidden by phase space in the free case. In particular, we find that for momentum transferred squared close to the maximum value, the Fermi motion changes drastically the shape of d sigma / dt, to the point that the ratio of this cross section to the free one becomes very sensitive to the precise value of t chosen, or the size of the bin used in an experimental analysis. Hence, this particular region of t does not seem the most indicated to find effects of a possible phi absorption in the deuteron. This reaction is studied theoretically as a function of t and the effect of the experimental angular cuts at LEPS is also discussed, providing guidelines for future experimental analyses of the reaction.

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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