261 research outputs found
New Implications of Lorentz Violation
In this proceedings, I summarize two recently discovered theoretical
implications that Lorentz violation has on physical systems. First, I discuss
new models for neutrino oscillations in which relatively simple combinations of
Lorentz-violating parameters can mimic the major features of the current
neutrino oscillation data. Second, I will present results on Yang-Mills
instantons in Lorentz-violating background fields. An explicit solution is
presented for unit winding number in SU(2).Comment: 8 pages, proceedings for 2003 Coral Gables Conference, Ft.
Lauderdale, F
Computer program for obtaining thermodynamic and transport properties of air and products of combustion of ASTM-A-1 fuel and air
A computer program for determining desired thermodynamic and transport property values by means of a three-dimensional (pressure, fuel-air ratio, and either enthalpy or temperature) interpolation routine was developed. The program calculates temperature (or enthalpy), molecular weight, viscosity, specific heat at constant pressure, thermal conductivity, isentropic exponent (equal to the specific heat ratio at conditions where gases do not react), Prandtl number, and entropy for air and a combustion gas mixture of ASTM-A-1 fuel and air over fuel-air ratios from zero to stoichiometric, pressures from 1 to 40 atm, and temperatures from 250 to 2800 K
Lorentz-Violating Extension of the Standard Model
In the context of conventional quantum field theory, we present a general Lorentz-violating extension of the minimal SU(3) x SU(2) x U(1) standard model including CPT-even and CPT-odd terms. It can be viewed as the low-energy limit of a physically relevant fundamental theory with Lorentz-covariant dynamics in which spontaneous Lorentz violation occurs. The extension has gauge invariance, energy-momentum conservation, and covariance under observer rotations and boosts, while covariance under particle rotations and boosts is broken. The quantized theory is hermitian and power-counting renormalizable, and other desirable features such as microcausality, positivity of the energy, and the usual anomaly cancellation are expected. Spontaneous symmetry breaking to the electromagnetic U(1) is maintained, although the Higgs expectation is shifted by a small amount relative to its usual value and the field acquires a small expectation. A general Lorentz-breaking extension of quantum electrodynamics is extracted from the theory, and some experimental tests are considered. In particular, we study modifications to photon behavior. One possible effect is vacuum birefringence, which could be bounded from cosmological observations by experiments using existing techniques. Radiative corrections to the photon propagator are examined. They are compatible with spontaneous Lorentz and CPT violation in the fermion sector at levels suggested by Planck-scale physics and accessible to other terrestrial laboratory experiments
Yang-Mills Instantons with Lorentz Violation
An analysis is performed of instanton configurations in pure Euclidean
Yang-Mills theory containing small Lorentz-violating perturbations that
maintain gauge invariance. Conventional topological arguments are used to show
that the general classification of instanton solutions involving the
topological charge is the same as in the standard case. Explicit solutions are
constructed for general gauge invariant corrections to the action that are
quadratic in the curvature. The value of the action is found to be unperturbed
to lowest order in the Lorentz-violating parameters.Comment: 16 page
Superfield Realizations of Lorentz and CPT Violation
Superfield realizations of Lorentz-violating extensions of the Wess-Zumino
model are presented. These models retain supersymmetry but include terms that
explicitly break the Lorentz symmetry. The models can be understood as arising
from superspace transformations that are modifications of the familiar one in
the Lorentz-symmetric case.Comment: 10 page
Exact calculation of the radiatively-induced Lorentz and CPT violation in QED
Radiative corrections arising from the axial coupling of charged fermions to
a constant vector b_\mu can induce a Lorentz- and CPT-violating Chern-Simons
term in the QED action. We calculate the exact one-loop correction to this term
keeping the full b_\mu dependence, and show that in the physically interesting
cases it coincides with the lowest-order result. The effect of regularization
and renormalization and the implications of the result are briefly discussed.Comment: LaTex, 8 pages; minor correction
Sensitivity of CPT Tests with Neutral Mesons
The sensitivity of experiments with neutral mesons to possible indirect CPT
violation is examined. It is shown that experiments conventionally regarded as
equivalent can have CPT reaches differing by orders of magnitude within the
framework of a minimal CPT- and Lorentz-violating extension of the standard
model.Comment: 4 pages REVTeX, published in Physical Review Letter
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