Neutron EDM from Electric and Chromoelectric Dipole Moments of Quarks

Abstract

Using QCD sum rules, we calculate the electric dipole moment of the neutron d_n induced by all CP violating operators up to dimension five. We find that the chromoelectric dipole moments of quarks \tilde d_i, including that of the strange quark, provide significant contributions comparable in magnitude to those induced by the quark electric dipole moments d_i. When the theta term is removed via the Peccei-Quinn symmetry, the strange quark contribution is also suppressed and d_n =(1\pm 0.5)[1.1e(\tilde d_d + 0.5\tilde d_u)+1.4(d_d-0.25d_u)].

Figures (2)

• Figure 1: Various classes of diagrams contributing to the CP-odd structure $\{F\sigma\gamma_5,\slash{\!\!\!p}\}$.
• Figure 2: The neutron EDM function $\nu(M^2($GeV$^2))$ is plotted according to the sum rules (a) and (b).