One-loop nonbirefringent effects on the electromagnetic vertex in the Standard Model Extension

Moyotl, A.; Novales‐Sánchez, H.; Toscano, J. J.; Tututi, E. S.

doi:10.1142/s0217751x14501073

Cited by 24 publications

(15 citation statements)

References 48 publications

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“…The essential observation 6 As shown in Refs. [119,120], nonconservation of Lorentz symmetry allows for a richer structure of this parametrization.…”

Section: With Both Cases Taken Intomentioning

confidence: 99%

Effects of universal extra dimensions on top-quark electromagnetic interactions

Montaño

Novales‐Sánchez

Toscano

2019

J. Phys. G: Nucl. Part. Phys.

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Universal extra dimensions, presumably observable at some high-energy scale, would modify lowenergy observables, being particularly relevant for physical processes forbidden at tree level by the Standard Model. We address the Kaluza-Klein contributions from the 5-dimensional Standard Model to the anomalous magnetic moment and to branching ratios of electromagnetic decays of the top quark. In accordance with present bounds on the compactification scale, contributions to both quantities are found to be at least 3 orders of magnitude below Standard-Model predictions.

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“…The essential observation 6 As shown in Refs. [119,120], nonconservation of Lorentz symmetry allows for a richer structure of this parametrization.…”

Section: With Both Cases Taken Intomentioning

confidence: 99%

Effects of universal extra dimensions on top-quark electromagnetic interactions

Montaño

Novales‐Sánchez

Toscano

2019

J. Phys. G: Nucl. Part. Phys.

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“…As one example, the apparent anomaly discrepancy can be reproduced in unified models with vector-like leptons having couplings g ≃ 1=2 and masses ≃150 GeV, yielding concomitant signals at the LHC [56]. Calculations of one-loop corrections to the anomaly in special Lorentz-violating models have also been performed [57]. Here, we consider a different idea, based on the result (42) showing that the presence of Lorentz violation can shift the measured value of ω AE a .…”

Section: Boostmentioning

confidence: 99%

Laboratory tests of Lorentz andCPTsymmetry with muons

2014

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The prospects are explored for testing Lorentz and CPT symmetry in the muon sector via the spectroscopy of muonium and various muonic atoms, and via measurements of the anomalous magnetic moments of the muon and antimuon. The effects of Lorentz-violating operators of both renormalizable and nonrenormalizable dimensions are included. We derive observable signals, extract first constraints from existing data on a variety of coefficients for Lorentz and CPT violation, and estimate sensitivities attainable in forthcoming experiments. The potential of Lorentz violation to resolve the proton radius puzzle and the muon anomaly discrepancy is discussed.

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“…For the inverse to be found, we use a suitable basis of tensor operators, a procedure that turned out to be successful in several theoretical scenarios [61,62]. Thus, we propose the following Ansatz :…”

Section: Maxwell Electrodynamics Modified By a Cpt-odd Dimension-mentioning

confidence: 99%

Maxwell electrodynamics modified by a CPT -odd dimension-five higher-derivative term

et al. 2019

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In this paper, we consider an electrodynamics of higher derivatives coupled to a Lorentz-violating background tensor. Specifically, we are interested in a dimension-five term of the CPT -odd sector of the nonminimal Standard-Model Extension. By a particular choice of the operatorkAF , we obtain a higher-derivative version of the Carroll-Field-Jackiw (CFJ) term, 1 2 κλµν A λ Dκ Fµν , with a Lorentz-violating background vector Dκ. This modification is subject to being investigated. We calculate the propagator of the theory and from its poles, we analyze the dispersion relations of the isotropic and anisotropic sectors. We verify that classical causality is valid for all parameter choices, but that unitarity of the theory is generally not assured. The latter is found to break down for certain configurations of the background field and momentum. In an analog way, we also study a dimension-five anisotropic higher-derivative CFJ term, which is written as κλµν A λ Tκ(T ·∂) 2 Fµν and is directly linked to the photon sector of Myers-Pospelov theory. Within the second model, purely timelike and spacelike Tκ are considered. For the timelike choice, one mode is causal, whereas the other is noncausal. Unitarity is conserved, in general, as long as the energy stays real -even for the noncausal mode. For the spacelike scenario, causality is violated when the propagation direction lies within certain regimes. However, there are particular configurations preserving unitarity and strong numerical indications exist that unitarity is guaranteed for all purely spacelike configurations. The results improve our understanding of nonminimal CPT-odd extensions of the electromagnetic sector.Here, we also stated the general structure of individual terms. A generic dimensionless background tensor with a set X of Lorentz indices is indicated by n X whereÔ X is a field operator with the same set of Lorentz indices. The mass dimension of the background has been extracted explicitly to show the dependence on the scales M QG and M . The remaining Lagrange density δL other contains all additional contributions that have not been taken into account previously. These could be nonperturbative in nature. According to the perturbative series of Eq. (1), the nonminimal SME is a natural extension of the higher-derivative Lorentz-invariant contributions in the same sense as the minimal SME is an extension of the SM. Searching for physics beyond the SM via an effective theory, there is a priori no reason why such nonminimal terms should be discarded. Interpreting these terms as theories that are valid within a certain energy range only, power-counting nonrenormalizability is not considered to be a problem.Due to the arguments explained above, individual terms have an energy dependence of the form (E/M QG ) d−4 and (E/M ) d−4 , respectively. Nonminimal contributions grow with energy, i.e., after a certain point they dominate the minimal ones. Therefore, they might be essential in experiments involving particles of high energies, e.g., cosmic rays. From the ...

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One-loop nonbirefringent effects on the electromagnetic vertex in the Standard Model Extension

Cited by 24 publications

References 48 publications

Effects of universal extra dimensions on top-quark electromagnetic interactions

Effects of universal extra dimensions on top-quark electromagnetic interactions

Laboratory tests of Lorentz andCPTsymmetry with muons

Maxwell electrodynamics modified by a CPT -odd dimension-five higher-derivative term

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