The electric dipole moment of the deuteron from the QCD θ-term

Abstract

The two-nucleon contributions to the electric dipole moment (EDM) of the deuteron, induced by the QCD θ-term, are calculated in the framework of effective field theory up-to-and-including next-tonext-to-leading order. In particular we find for the difference of the deuteron EDM and the sum of proton and neutron EDM induced by the QCD θ-term a value of (−5.4 ± 3.9)θ × 10 −4 e fm. The by far dominant uncertainty comes from the CP-and isospin-violating πN N coupling constant.PACS. 11.30.Er Charge conjugation, parity, time reversal, and other discrete symmetries -13.40.Em Electric and magnetic moments -24.80.+y Nuclear tests of fundamental interactions and symmetries -21.10.Ky Electromagnetic moments

Nuclear electric dipole moments in chiral effective field theory

“…The results for the phenomenological potentials considered are also shown in table 1 and agree (where a comparison is possible) with those in refs. [9][10][11][12][13][14][15][16][17]. The values from chiral and phenomenological potentials are in excellent agreement.…”

“…The concept of probing the QCD θ-term and BSM physics using EDMs of light nuclei has attracted much attention in recent years [8][9][10][11][12][13][14][15][16][17][18][19][20] and is the basic idea underlying plans for EDM measurements in dedicated storage rings [21][22][23][24][25]. The main advantage of light nuclei is that the associated nuclear physics is theoretically well under control, such that these systems can be used to probe the underlying CP-violating mechanism.…”

“…The various sources of CP violation at the energy scale Λ χ ∼ 1 GeV induce, in principle, an infinite set of CP-violating terms in the effective low-energy pion-nucleon Lagrangian that, however, can be ordered by a power-counting scheme [8,15,16,18,26]. It was concluded that the leading EDM contributions for nucleons and light nuclei can be expressed in terms of seven interactions:…”

“…the θ-term and dimension-six sources) are expected to contribute to all CP-violating operators in eq. (1.1), but at different strengths based on the field content and chiral-symmetry properties of the source [10,15,16,18,19]. Different sources therefore yield different hierarchies of nucleon and nuclear EDM contributions which can explicitly be probed by EDM measurements.…”

“…Other irreducible CP-conserving and CP-violating current operators only contribute toJ µ at N 2 LO as discussed in [15,16,18] and are thus irrelevant for this work. For 2N operators we use the definitions…”