Data tables for Lorentz and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>C</mml:mi><mml:mi>P</mml:mi><mml:mi>T</mml:mi></mml:math>violation

Kostelecký, V. Alan; Russell, Neil

doi:10.1103/revmodphys.83.11

Cited by 1,161 publications

(1,203 citation statements)

References 110 publications

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“…This possibility is interesting on its own right and has received a great deal of attention recently, the prototypical models describing the possible patterns of Lorentz symmetry breaking being the Einstein-aether [19] and the ghost condensate [20] theories. A major issue in this kind of theories is the possible transmission of Lorentz breaking to the fields of the Standard Model (SM) which would be unacceptable as Lorentz invariance is tested to a very high precision in the SM sector [21]. Nevertheless, this problem is completely unrelated to DE and may be addressed using some dynamical mechanisms [22,23,24].…”

Section: Introductionmentioning

confidence: 99%

Technically natural dark energy from Lorentz breaking

Blas¹,

Sibiryakov²

2011

J. Cosmol. Astropart. Phys.

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We construct a model of dark energy with a technically natural small contribution to cosmic acceleration, i.e. this contribution does not receive corrections from other scales in the theory. The proposed acceleration mechanism appears generically in the low-energy limit of gravity theories with violation of Lorentz invariance that contain a derivatively coupled scalar field Θ. The latter may be the Goldstone field of a broken global symmetry. The model, that we call ΘCDM, is a valid effective field theory up to a high cutoff just a few orders of magnitude below the Planck scale. Furthermore, it can be ultraviolet-completed in the context of Hořava gravity. We discuss the observational predictions of the model. Even in the absence of a cosmological constant term, the expansion history of the Universe is essentially indistinguishable from that of ΛCDM. The difference between the two theories appears at the level of cosmological perturbations. We find that in ΘCDM the matter power spectrum is enhanced at subhorizon scales compared to ΛCDM. This property can be used to discriminate the model from ΛCDM with current cosmological data.

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Section: Introductionmentioning

confidence: 99%

Technically natural dark energy from Lorentz breaking

Blas¹,

Sibiryakov²

2011

J. Cosmol. Astropart. Phys.

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“…Analogous observations can be made for the various terms inside the Γ µ structure of (15). There are very stringent bounds on the various coefficients appearing in (15), coming from a plethora of precision experiments [22], including antimatter factories of interest to this conference. Our model with the H-torsion coupling to fermions is obtained from (15) by setting all SME coefficients to zero except b 0 which is to be identified with the temporal component of the constant…”

Section: Current Era Of the Universe And Compatibility Of H-torsion Wmentioning

confidence: 72%

“…The coupling of the RHN to the torsion has non trivial CP violating effects in its decay to Higgs and active neutrinos, leading to a lepton asymmetry, which is estimated. Finally, Section 4 demonstrates the compatibility of the model with current era phenomenology, which implies stringent bounds on torsion and other Lorentz and CPT violating parameters [22], within the Standard Model extension (SME) framework [23], which the effective low energy theory of this model belongs to.…”

Section: Theoretical Motivations For Lorentz and Cpt Violationmentioning

confidence: 99%

Proceedings of the 12th International Conference on Low Energy Antiproton Physics (LEAP2016)

Hiyama¹,

Kanai²,

Ulmer

et al. 2017

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I review briefly string-inspired models of the Early Universe in which the Robertson-Walker geometry is extended to involve appropriate torsion fields that are constant in the frame of a cosmological observer. Fermion fields in such geometries are described by Lagrangians that fall in the simplest Lorentz-and CPT-violating extensions of the Standard Model (SME), in which the fermions couple to a constant axial vector background b µ γ 5 , with the b µ "axion-like" field associated to torsion. In the talk I also review mechanisms to suppress the torsion in the current era, compatible with the existing stringent upper bounds, which are of relevance to searches for CPT violation of interest to this conference. KEYWORDS:Early Universe, Torsion, Strings, Standard Model Extension, CPT Violation Theoretical motivations for Lorentz and CPT ViolationBaryogenesis/Leptogenesis, that is processes in the early Universe that lead to the observed matter-antimatter asymmetry in the Cosmos, represent a long-standing unresolved issue in cosmology [1]. Many approaches to the problem proposed in the literature [2] but no consensus has emerged on the potential mechanisms. Many of them predict lepton number violation, and in particular some of them entail [3] a µ → e − γ interaction with predictions on the corresponding branching ratio which may be falsified at the next generation experiments, but others are more difficult to falsify.A standard measure of the abundance of baryons over that of antibaryons is defined by the ratiowhere n B is the number density of baryons, nB is the number density of antibaryons and n γ is the density of photons (proportional to the entropy density s). This number was determined with accurate measurements of the CMB radiation by the experiments WMAP [5] and Planck [6]. However, there is no experimental evidence for primordial antimatter in the visible universe. Similarly, the generation of an asymmetry between leptons and antileptons is known as leptogenesis. This is expected to be of the same order of magnitude as Y ∆B . If B, the net baryon number, is conserved in Nature, the matter asymmetry can only originate from an asymmetric initial condition B 0. However, such an asymmetry would rapidly diminish during inflation, and extreme fine tuning of the initial condition would become necessary. This is highly unsatisfactory from a theoretical point of view. Consequently a mechanism for the dynamical generation of a baryon asymmetry is required. In the seminal paper [7], Sakharov identified three sufficient conditions that must be satisfied in order to produce a net baryon number.(1) The theory must allow for interactions that violate B conservation. These interactions must become effective at high energy scales in order to guarantee the stability of the proton. (2) Both discrete symmetries C (charge conjugation) and CP (where P denotes parity) are violated.In fact C violation is not enough, as correlations between the spins of particles and antiparticles 1

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“…This bound state is also considered for observation of the gravitational quantum states [6]. All of these systems, among others, are used in the Standard Model Extension framework for Lorentz and CPT tests [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Studies of discrete symmetries in decays of positronium atoms

Czerwiński

Curceanu

Dulski

et al. 2018

EPJ Web of Conferences

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Abstract.A positronium -a bound state of electron and positron -is an eigenstate of parity and charge conjugation operators which decays into photons. It is a unique laboratory to study discrete symmetries whose precision is limited, in principle, by the effects due to the weak interactions expected at the level of 10 −14 and photon-photon interactions expected at the level of 10 −9 . The Jagiellonian Positron Emission Tomograph (J-PET) is a detector for medical imaging as well as for physics studies involving detection of electronpositron annihilation into photons. The physics case covers the areas of discrete symmetries studies and genuine multipartite entanglement. The J-PET detector has high angular and time resolution and allows for determination of spin of the positronium and the momenta and polarization vectors of annihilation quanta. In this article, we present the potential of the J-PET system for studies of discrete symmetries in decays of positronium atoms.

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Data tables for Lorentz andCPTviolation

Cited by 1,161 publications

References 110 publications

Technically natural dark energy from Lorentz breaking

Technically natural dark energy from Lorentz breaking

Proceedings of the 12th International Conference on Low Energy Antiproton Physics (LEAP2016)

Studies of discrete symmetries in decays of positronium atoms

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