Gauge invariance in the presence of a cutoff - Nuclear TheoryReportar como inadecuado

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Abstract: We use the method of gauging equations to construct the electromagneticcurrent operator for the two-nucleon system in a theory with a finite cutoff.The employed formulation ensures that the two-nucleon T-matrix andcorresponding five-point function, in the cutoff theory, are identical to theones formally defined by a reference theory without a cutoff. A feature of ourapproach is that it effectively introduces a cutoff into the reference theoryin a way that maintains the long-range part of the exchange current operator;for applications to effective field theory EFT, this property is usuallysufficient to guarantee the predictive power of the resulting cutoff theory. Inaddition, our approach leads to Ward-Takahashi WT identities that are linearin the interactions.From the point of view of EFT-s where such a WT identity is satisfied in thereference theory, this ensures that gauge invariance in the cutoff theory ismaintained order by order in the expansion.

Autor: A. N. Kvinikhidze, B. Blankleider, E. Epelbaum, C. Hanhart, M. Pavón Valderrama


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