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arXiv 0905.4943nucl-th
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手征有效理论中NN相互作用的减重整化直到次次领头阶:S波

Subtractive renormalization of the NN interaction in chiral effective theory up to next-to-next-to-leading order: S waves

C. -J. Yang, Ch. Elster, D. R. Phillips

摘要:

我们扩展我们的减法重整化方法,以评估的1 S 0和3S 1 - 3D 1 NN散射相移的次次领头阶(NNLO)的手征有效理论。我们表明,如果能量依赖的接触项采用NN势,1 S 0相移可以通过进行两个减法Lippmann-Schwinger方程。这些减法使用的知识的散射长度和1 S 0相移在特定的能量,以消除低能量常数的接触相互作用从散射方程。对于J=1耦合通道,可以通过三个减法来实现类似的重正化,这三个减法采用3S 1散射长度、特定能量处的3S 1相移和3S 1 - 3D 1广义散射长度的知识。在这两个通道中,类似的方法可以应用于具有动量相关接触项的势,除了在这种情况下,其中一个减法必须由一个实验数据的拟合代替。这种方法允许在李普曼-施温格方程中使用任意高的截止值。我们研究的NNLO S波相移截止高达5 GeV,并表明,存在的NN潜在的线性能量依赖创建虚假的极点在散射振幅。因此,结果与经验数据相冲突,在相当大的部分所考虑的截止范围。我们还确定了使用的截止大于1 GeV时,动量依赖的接触相互作用的问题。通过对NN势的两π交换部分进行谱函数正则化,这些问题得到了改善,但没有消除

英文摘要:

We extend our subtractive-renormalization method in order to evaluate the 1S0 and 3S1-3D1 NN scattering phase shifts up to next-to-next-to-leading order (NNLO) in chiral effective theory. We show that, if energy-dependent contact terms are employed in the NN potential, the 1S0 phase shift can be obtained by carrying out two subtractions on the Lippmann-Schwinger equation. These subtractions use knowledge of the the scattering length and the 1S0 phase shift at a specific energy to eliminate the low-energy constants in the contact interaction from the scattering equation. For the J=1 coupled channel, a similar renormalization can be achieved by three subtractions that employ knowledge of the 3S1 scattering length, the 3S1 phase shift at a specific energy and the 3S1-3D1 generalized scattering length. In both channels a similar method can be applied to a potential with momentum-dependent contact terms, except that in that case one of the subtractions must be replaced by a fit to one piece of experimental data. This method allows the use of arbitrarily high cutoffs in the Lippmann-Schwinger equation. We examine the NNLO S-wave phase shifts for cutoffs as large as 5 GeV and show that the presence of linear energy dependence in the NN potential creates spurious poles in the scattering amplitude. In consequence the results are in conflict with empirical data over appreciable portions of the considered cutoff range. We also identify problems with the use of cutoffs greater than 1 GeV when momentum-dependent contact interactions are employed. These problems are ameliorated, but not eliminated, by the use of spectral-function regularization for the two-pion exchange part of the NN potential

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