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Dominant $2πγ$-exchange nucleon-nucleon interaction: Spin-spin and tensor potentials

N. Kaiser
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Abstract

We calculate at two-loop order in chiral perturbation theory the electromagnetic corrections to the two-pion exchange nucleon-nucleon interaction that is generated by the isovector spin-flip $ππNN$ contact-vertex proportional to the large low-energy constant $c_4\simeq 3.4 $GeV$^{-1}$. We find that the respective $2πγ$-exchange potentials contain sizeable isospin-breaking components which reach up to -4% of corresponding isovector $2π$-exchange potentials. The typical values of these novel charge-independence breaking spin-spin and tensor potentials are $-0.11 $MeV and $0.09 $MeV, at a nucleon distance of $r=m_π^{-1}=1.4 $fm. The charge-symmetry breaking spin-spin and tensor potentials come out a factor of 2.4 smaller. Our analytical results for these presumably dominant isospin-violating spin-spin and tensor NN-forces are in a form such that they can be easily implemented into phase-shift analyses and few-body calculations.

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N. Kaiser. 2006-10-24. Dominant $2πγ$-exchange nucleon-nucleon interaction: Spin-spin and tensor potentials. https://doi.org/10.1103/physrevc.74.067001

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