scholarly journals Neutron Electric Dipole Moment on the Lattice

2018 ◽  
Vol 175 ◽  
pp. 01014 ◽  
Author(s):  
Boram Yoon ◽  
Tanmoy Bhattacharya ◽  
Rajan Gupta

For the neutron to have an electric dipole moment (EDM), the theory of nature must have T, or equivalently CP, violation. Neutron EDM is a very good probe of novel CP violation in beyond the standard model physics. To leverage the connection between measured neutron EDM and novel mechanism of CP violation, one requires the calculation of matrix elements for CP violating operators, for which lattice QCD provides a first principle method. In this paper, we review the status of recent lattice QCD calculations of the contributions of the QCD Θ-term, the quark EDM term, and the quark chromo-EDM term to the neutron EDM.

2008 ◽  
Vol 23 (17n20) ◽  
pp. 1397-1408 ◽  
Author(s):  
JEN-CHIEH PENG

The neutron electric dipole moment (EDM) provides unique information on CP violation and physics beyond the Standard Model. We first review the history of experimental searches for neutron electric dipole moment. The status of future neutron EDM experiments, including experiments using ultra-cold neutrons produced in superfluid helium, will then be presented.


2007 ◽  
Vol 85 (6) ◽  
pp. 597-606
Author(s):  
A Ritz

We dicuss the utility of precision probes for flavour-diagonal CP-violation, namely, searches for electric dipole moments of nucleons, atoms, and molecules, in looking for new physics thresholds that manifest themselves primarily through higher dimensional operators. After reviewing the status of the electric dipole moment (EDM) constraints, we consider first the sensitivity to a generic class of dimension-five operators generated at a supersymmetric threshold, through their contribution to CP- and flavour-violating observables. Such thresholds can be probed by EDMs up to a scale of order 108 GeV depending on the flavour structure. We then turn to consider the possibility that electroweak baryogenesis is made feasible by the introduction of dimension-six operators at a TeV-scale threshold. The EDM costraints on dimension-six couplings of the Higgs to the fermions currently still allow a reasonable window in parameter space for these models, but the next generation of experiments should provide a conclusive test. PACS Nos.: 11.30.Er, 12.60.Fr, 12.60.Jv


2002 ◽  
Vol 17 (23) ◽  
pp. 1489-1497 ◽  
Author(s):  
C. Q. GENG ◽  
J. N. NG ◽  
T. H. WU

We study the CP violating effects in the decay of η → π+π- γ. We show that to have CP violation in the decay, one has to consider both linear and circular photon polarizations. In the standard model, the polarizations are vanishingly small. However, model independently, i.e. using only experimental constraint imposed by the limit on Br (η → π+ π-), it can be up to O(10%). We also explore various possible operators and we find that the tensor type operator, possibly arising from a nonzero CP violating electric dipole moment of the strange quark, can induce a sizable linear photon polarization.


2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Vincenzo Cirigliano ◽  
Emanuele Mereghetti ◽  
Peter Stoffer

Abstract We define a regularization-independent momentum-subtraction scheme for the C P -odd three-gluon operator at dimension six. This operator appears in effective field theories for heavy physics beyond the Standard Model, describing the indirect effect of new sources of C P-violation at low energies. In a hadronic context, it induces permanent electric dipole moments. The hadronic matrix elements of the three-gluon operator are non-perturbative objects that should ideally be evaluated with lattice QCD. We define a non-perturbative renormalization scheme that can be implemented on the lattice and we compute the scheme transformation to $$ \overline{\mathrm{MS}} $$ MS ¯ at one loop. Our calculation can be used as an interface to future lattice-QCD calculations of the matrix elements of the three-gluon operator, in order to obtain theoretically robust constraints on physics beyond the Standard Model from measurements of the neutron electric dipole moment.


2012 ◽  
Vol 27 (16) ◽  
pp. 1230015 ◽  
Author(s):  
TAKESHI FUKUYAMA

This is a theoretical review of exploration of new physics beyond the Standard Model (SM) in the electric dipole moment (EDM) in elementary particles, atoms and molecule. EDM is a very important CP violating phenomenon and sensitive to new physics. Starting with the estimations of EDM of quarks–leptons in SM, we explore new signals beyond SM. However, these works drive us to wider frontiers where we search fundamental physics using atoms and molecules and vice versa. Paramagnetic atoms and molecules have great enhancement factor on electron EDM. Diamagnetic atoms and molecules are very sensitive to nuclear P and T odd processes. Thus EDM becomes the keyword not only of New Physics but also of unprecedented fruitful collaborations among particle, atomic and molecular physics. This review intends to help such collaborations over a wide range of physicists.


2018 ◽  
Vol 191 ◽  
pp. 02003
Author(s):  
Alexey S. Zhevlakov ◽  
Mikhail Gorchtein ◽  
Astrid N. Hiller Blin ◽  
Valery E. Lyubovitskij

The data for the upper limit on the electric dipole moment of the neutron (nEDM) can be explained by using different mechanisms beyond the Standard Model (SM). The nEDM can be generated by a CP-violating transition of η and η′ mesons into pion pairs. We derive the upper limits for the rates of the CP-violating decays η(η′) → 2π are by orders of magnitude more stringent than those from existing experiments so far.


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