2021/04/26 by Janardan Prasad Singh, Singh, Janardan Prasad
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th) #hep-ph #nucl-th
paper · pdf · doi:10.48550/arxiv.2104.12371
22 pages, 26 figures and 3 tables; some text added but no changes in final results and conclusions; version accepted for publication in Nucl. Phys. A
arxiv created 2022/06/30 · arxiv updated 2022/07/01
We have calculated coupling constants of a neutral pion with the lowest two nucleon resonances. This includes both the diagonal as well as non-diagonal coupling constants involving a nucleon resonance and a nucleon. For this, we first calculate vacuum-to-pion correlation function of the interpolating fields of two nucleons and then take its matrix elements with respect to a nucleon spinor and/or a nucleon resonance spinor(s). Using different QCD sum rules obtained from different matrix elements we eliminate unwanted coupling constants and solve for the desired ones. This is a simple extension of the projected correlation function approach used in the literature where we use multiple of states involving those of a nucleon and its resonances. We have also checked the stability of our results with respect to variation of different QCD and phenomenological input parameters.