1992/10/20 by Tae-Sun Park, Park, Tae-Sun, Dong-Pil Min +3
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/9210248
11 pages, LaTeX file, SNUTP 92-82
arxiv created 1992/10/20 · arxiv updated 2009/11/30
We develop a systematic chiral perturbation expansion for the calculation of meson-exchange currents in nuclei and apply the formalism to nuclear axial currents. We summarize the principal results of such a calculation to one loop order on nuclear axial-charge transitions which provides a strong support to the conjecture of ``chiral filter phenomenon" in nuclear medium. The use of heavy baryon chiral perturbation theory enables us to obtain a remarkably simple result valid next to the leading order in chiral counting. The dominant role of a soft-pion exchange in axial-charge transitions in heavy nuclei is confirmed. An important, \it albeit indirect, consequence of our result on the empirically observed enhancement in axial-charge transitions in heavy nuclei is pointed out.