55566455
WISPy Cold Dark Matter
Very weakly interacting slim particles (WISPs), such as axion-like particles (ALPs) or hidden photons (HPs), may be non-thermally produced via the misalignment mechanism in the early universe and survive as a cold dark matter population until today. We nd that, both for ALPs and HPs whose dominant interactions with the standard model arise from couplings to photons, a huge region in the parameter spaces spanned by photon coupling and ALP or HP mass can give rise to the observed cold dark matter. Remarkably, a large region of this parameter space coincides with that predicted in well motivated models of fundamental physics. A wide range of experimental searches { exploiting haloscopes (direct dark matter searches exploiting microwave cavities), helioscopes (searches for solar ALPs or HPs), or light-shining-through-a-wall techniques { can probe large parts of this parameter space in the foreseeable future.
118294407
Illuminating WISPs with Photons
Physics beyond the Standard Model naturally gives rise to very light and weakly interacting particles, dubbed WISPs (Weakly Interacting Slim Particles). A prime example is the axion, that has eluded experimental detection for more than thirty years. In this talk we will review some of the strongly motivated candidates for such particles, the observational hints for them and the present status of searches with photon regeneration experiments, as well as possible future improvements.
119184475
Effects of heavy bosonic excitations on QED vacuum
We discuss the contribution of axion-like excitations (ALE) to the vacuum birefringence in the limit mA ≳ ω, where mA is the mass of the excitation and ω the energy of test photons interacting with an external (intense) magnetic field. The relevance of this term with respect to the QED contribution depends on the ratio gA/mA and, from present bounds on the mass and the coupling constant gA, we find that in the present low energy regime, it ranges from 10-14 to 102 suggesting an interesting alternative to explore.
119160303
Chiral anomaly beyond Lorentz invariance
The chiral anomaly in the context of an extended standard model with Lorentz invariance violation is studied. Taking into account bounds from measurements of the speed of light, we argue that the chiral anomaly and its consequences are general results valid even beyond the relativistic symmetry.
117024657
Electrodynamics with an Infrared Scale and PVLAS experiment
We consider an infrared Lorentz violation in connection with recent results of PVLAS experiment. Our analysis is based in a relation that can be established, under certain conditions, between an axial-like-particle theory and electrodynamics with an infrared scale. In the PVLAS case, the conditions imply two dispersion relations such that the infrared scale $|\vec \theta|$, the inverse axion-photon coupling constant $M^{-1}$ and the external magnetic field ${\vec B}$ can be connected through the formula $|{\vec \theta}|= {|\vec B|}/M$. Our analysis, which only requires a non-dynamical (auxiliar) axial-like field leads to $|{\vec\theta}| \leq 5.4 \times 10^{-7}$ meV and $M^{-1} \sim 1.2 \times 10^{-3}$ GeV $^{-1}$.
119351968
CPT/Lorentz Invariance Violation and Quantum Field Theory
Departamento de Fisica, Universidad de Santiago de ChileCasilla 307, Santiago 2, ChileE-mail: fmendez@lauca.usach.clAnalogies between the noncommutative harmonic oscillator and noncommutative ﬁelds are ana-lyzed. Following this analogywe construct examples of quantum ﬁelds theories with explicit CPTand Lorentz symmetry breaking. Some applications to baryogenesis and neutrino oscillation arealso discussed.Fifth International Conference on Mathematical Methods in Physics — IC2006April 24-28 2006Centro Brasilerio de Pesquisas Fisicas, Rio de Janeiro, Brazil
118605658
Geometric Representation of Interacting Non-Relativistic Open Strings using Extended Objects
Non-relativistic charged open strings coupled with Abelian gauge fields are quantized in a geometric representation that generalizes the Loop Representation. The model consists of open-strings interacting through a Kalb-Ramond field in four dimensions. The geometric representation proposed uses lines and surfaces that can be interpreted as an extension of the picture of Faraday's lines of classical electromagnetism. This representation results to be consistent, provided the coupling constant (the "charge" of the string) is quantized. The Schr\"odinger equation in this representation is also presented.
117936607
Covariance of the selfdual vector model
The Poisson algebra between the fields involved in the vectorial selfdual action is obtained by means of the reduced action. The conserved charges associated with the invariance under the inhomogeneous Lorentz group are obtained and its action on the fields. The covariance of the theory is proved using the Schwinger-Dirac algebra. The spin of the excitations is discussed.
53942626
Interacting particles and strings in path and surface representations
Nonrelativistic charged particles and strings coupled with Abelian gauge fields are quantized in a geometric representation that generalizes the loop representation. We consider three models: the string in self-interaction through a Kalb-Ramond field in four dimensions, the topological interaction of two particles due to a BF term in $2+1$ dimensions, and the string-particle interaction mediated by a BF term in $3+1$ dimensions. In the first case one finds that a consistent ``surface representation'' can be built provided that the coupling constant is quantized. The geometrical setting that arises corresponds to a generalized picture of the lines of Faraday: quantum states are labeled by the shape of the string, from which emanate ``Faraday's surfaces.'' In the other models, the topological interaction can also be described by geometrical means. It is shown that the open-path (or open-surface) dependence carried by the wave functional in these models can be eliminated through a unitary transformation, except by the remaining dependence on the boundary of the path (or surface). This feature is closely related to the presence of anomalous statistics in the $2+1$ model, and to a generalized ``anyonic behavior'' of the string in the other case.
16377160
Topological sectors and gauge invariance in massive vector-tensor theories in D≥4
Abstract A family of locally equivalent models is considered. They can be taken as a generalization to d + 1 dimensions of the Topological Massive and “Self-dual” models in 2+1 dimensions. The corresponding 3+1 models are analized in detail. It is shown that one model can be seen as a gauge fixed version of the other, and their space of classical solutions differs in a topological sector represented by the classical solutions of pure BF model. The topological sector can be gauged out on cohomologically trivial base manifolds but on general settings it may be responsible of the difference in the long distance behaviour of the models. The presence of this topological sector appears explicitly in the partition function of the theories. The generalization of this models to higher dimensions is shown to be straightfoward.
118915291
Canonical equivalence between massive spin 1 theories
The model of Cremmer-Scherck and Proca are considered in dimensions greater than 3+1. It is obtained that the Proca model correspond to a gauged fixed version of the Cremmer-Scherck one, and we show their canonical equivalence.