Perturbative QCD Prediction of the Hyperon EDM from CP-violating Dipole Interactions

Abstract

Electric dipole moment (EDM) of baryons provides a sensitive probe of CP-violating interactions beyond the Standard Model. Motivated by the recent BESIII measurement on the $\Lambda$-hyperon EDM [1], we present the first perturbative QCD analysis of the $\Lambda$ EDM form factor to elucidate its origin in CP-violating quark dipole interactions. In particular, we derive a QCD factorization formula that relates the $\Lambda$ EDM form factor to quark EDMs and chromo-electric dipole moments (CEDMs) through convolutions with the light-cone distribution amplitudes of $\Lambda$. These connections allow us to extract constraints on CP-violating dipole couplings from current and future hyperon EDM measurements. Our numerical analysis demonstrates that the $\Lambda$ EDM exhibits unique sensitivity to the strange-quark CEDM, providing complementary information to that obtained from the neutron EDM.

Comments: 9 pages, 2 figures; version published in PRL