This title appears in the Scientific Report :
2014
Electric Dipole Moments of Light Nuclei in Chiral Effective Field Theory
Electric Dipole Moments of Light Nuclei in Chiral Effective Field Theory
Electric dipole moments (EDMs) break parity (P) and time-reversal (T) symmetry and thus, by the CPT theorem, CP-symmetry. Once measured, they will be unambiguous signs of new physics since CP violation from the complex phase of the Cabibbo-Kobayashi-Maskawa matrix in the Standard Model predicts EDMs...
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Personal Name(s): | Bsaisou, Jan (Corresponding Author) |
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Contributing Institute: |
Theorie der Starken Wechselwirkung; IAS-4 Theorie der starken Wechselwirkung; IKP-3 |
Published in: | 2014 |
Imprint: |
2014
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Physical Description: |
196 p. |
Dissertation Note: |
Bonn, Diss., 2014 |
Document Type: |
Dissertation / PhD Thesis |
Research Program: |
Hadron Structure and Dynamics (HSD) |
Subject (ZB): | |
Publikationsportal JuSER |
Electric dipole moments (EDMs) break parity (P) and time-reversal (T) symmetry and thus, by the CPT theorem, CP-symmetry. Once measured, they will be unambiguous signs of new physics since CP violation from the complex phase of the Cabibbo-Kobayashi-Maskawa matrix in the Standard Model predicts EDMs that are experimentally inaccessible in the foreseeable future. The theta-term of Quantum Chromodynamics (QCD) and extensions of the Standard Model such as supersymmetry and multi-Higgs scenarios comprise P- and T-violating interactions which are capable of inducing significantly larger EDMs. The extensions of the Standard Model give rise to a set of effective non-renormalizable operators of canonical dimension six at energies > 1 GeV when the heavy degrees of freedom are integrated out. The effective dimension-six operators are known as the quark EDM, the quark-chromo EDM, four-quark left-right operator, the gluon-chromo EDM and the four-quark operator. Starting from the QCD theta-term and this set of P- and T-violating effective dimension-six operators, we present a scheme to derive the induced effective Lagrangians at energies below Lambda-QCD ~ 200 MeV within the framework of Chiral Perturbation Theory (ChPT) for two quark flavors in the formulation of Gasser and Leutwyler. The differences among the sources of P and T violation manifest themselves at energies below Lambda-QCD in specific hierarchies of coupling constants of P- and T-violating vertices. We compute the relevant coupling constants of P- and T-violating hadronic vertices which are induced by the QCD theta-term with well-defined uncertainties as functions of the physical parameter theta-bar. The relevant coupling constants induced by the effective dimension-six operators are given as functions of yet unknown Low Energy Constants (LECs) which can not be determined within the framework of ChPT itself. Since the required supplementary input from e.g. Lattice QCD is not yet available, we present Naive Dimensional Analysis (NDA) estimates of the coupling constants. These estimates prove to be sufficient to reveal certain hierarchies of coupling constants.The different hierarchies of coupling constants translate into different hierarchies of the nuclear contributions to the EDMs of light nuclei. We calculate within the framework of ChPT the two-nucleon contributions to the EDM of the deuteron up to and including next-to-next-to leading order and the two-nucleon contributions to the EDMs of the helion (3He nucleus) and the triton (3H nucleus) up to and including next-to-leading order. These computations comprise thorough investigations of the uncertainties of the results from the P- and T-violating component as well as the P- and T-conserving component of the nuclear potential. We present quantitative predictions of the nuclear contributions to the EDMs of the deuteron, the helion and the triton induced by the QCD theta-term as functions of theta-bar with well-defined uncertainties. The EDM predictions for the effective dimension-six sources are given as function of the yet unknown LECs with NDA estimates. We present several strategies to falsify the QCD theta-term as a relevant source of P and T violation by a suitable combination of measurements of several light nuclei and, if needed, supplementary lattice QCD input. If the QCD theta-term fails these tests, one or several of the effective dimension-six sources encoding physics beyond the Standard Model are most likely the source(s) of P and T violation. We demonstrate how particular effective dimension-six sources can be tested by EDM measurements of light nuclei with eventually supplementary Lattice QCD input. |