Topic
Symmetry (physics)
About: Symmetry (physics) is a research topic. Over the lifetime, 26435 publications have been published within this topic receiving 500189 citations. The topic is also known as: symmetry (physics) & physical symmetry.
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TL;DR: In this paper, the minimal set of Higgs scalars, for models based on the local gauge group SU(3c⊗SU(3)L), were studied, and the exact tree-level scalar mass matrices resulting from symmetry breaking were calculated at the minimum of the most general scalar potential.
Abstract: We study the minimal set of Higgs scalars, for models based on the local gauge group SU(3)c⊗SU(3)L⊗U(1)X, which do not contain particles with exotic electric charges. We show that only two Higgs SU(3)L triplets are needed in order to properly break the symmetry. The exact tree-level scalar mass matrices resulting from symmetry breaking are calculated at the minimum of the most general scalar potential, and the gauge bosons are obtained, together with their couplings to the physical scalar fields. We show how the scalar sector introduced is enough to produce masses for fermions in a particular model. By using experimental results we constrain the scale of new physics to be above 1.5 TeV.
108 citations
TL;DR: In this paper, the general algebraic relations between space inversion, time reversal, and the internal symmetry group are analyzed within the framework of a Lorentz-invariant local field theory.
Abstract: The general algebraic relations between space inversion, time reversal, and the internal symmetry group are analyzed within the framework of a Lorentz-invariant local field theory. The problem of unitary representations of the full Poincar\'e group including the space and time reflection operators has been studied by Wigner, and the representations are classified into 4 cases. It is shown that, with the added assumption of the local field theory, Wigner's cases 2,3, and 4 either do not not occur or can be reduced to his case 1. The concept of minimal group extension is introduced and the related mathematical analysis is given. The symmetry properties under space inversion, time reversal, and other discrete operators such as charge conjugation are analyzed separately for each of the three known interactions: strong, electromagnetic, and weak.
108 citations
TL;DR: In this paper, the possibility of a small modification of spinor Quantum Electro-Dynamics is reconsidered, in which Lorentz and CPT non-covariant kinetic terms for photons and fermions are present.
Abstract: The possibility of a small modification of spinor Quantum Electro-Dynamics is reconsidered, in which Lorentz and CPT non-covariant kinetic terms for photons and fermions are present. The corresponding free field theory is carefully discussed. The finite one-loop parity-odd induced effective action is unambiguously calculated using the physical cutoff method, which manifestly encodes the maximal residual symmetry group allowed by the presence of the Lorentz and CPT breaking axial-vector. This very same induced effective action, which is different from those ones so far quoted in the Literature, is also re-derived by means of the dimensional regularization, provided the maximal residual symmetry is maintained in the enlarged D-dimensional space-time. As a consequence, it turns out that the requirement of keeping the maximal residual symmetry at the quantum level just corresponds to the physical renormalization prescription which naturally fixes the one-loop parity-odd induced effective action.
108 citations
TL;DR: In this article, the effect of flexible antennas upon the stability of motion of a spin-stabilized satellite was investigated, and the conclusion was that the motion is unstable if C A'9, however, the system depends on the ratio Os/con, where con is the natural undamped frequency of one oscillator.
Abstract: The effect of flexible antennas upon the stability of motion of a spin-stabilized satellite was investigated. The satellite is assumed to consist of a symmetric rigid body with two flexible rods that extend along the symmetry axis in opposite directions. First, a simplified model, replacing the flexible antennas by viscously damped oscillators, was considered. The analysis has been facilitated by representing the motions by means of complex vectors. The resulting equations were linearized, and an infinitesimal stability analysis was performed. The conclusion reached was that the motion is unstable if C A'9 however, the stability of the system depends on the ratio Os/con, where con is the natural undamped frequency of one oscillator. A time-dependent solution of the linearized equations by the Laplace transform method and a numerical solution of the nonlinear equations by the Runge-Kutta method were obtained. The agreement between the two solutions, for the values considered, was excellent. A series solution of the linearized equations corresponding to the continuous model indicates that the simplified model provides a good approximation of the continuous model.
108 citations
TL;DR: In this article, a unitary meson-baryon coupled-channel model that treats the heavy pseudoscalar and vector mesons on equal footing as required by heavy-quark symmetry is proposed.
Abstract: We study charmed baryon resonances that are generated dynamically within a unitary meson-baryon coupled-channel model that treats the heavy pseudoscalar and vector mesons on equal footing as required by heavy-quark symmetry. It is an extension of recent SU(4) models with t-channel vector-meson exchanges to an SU(8) spin-flavor scheme, but differs considerably from the SU(4) approach in how the strong breaking of the flavor symmetry is implemented. Some of our dynamically generated states can be readily assigned to recently observed baryon resonances, while others do not have a straightforward identification and require the compilation of more data as well as an extension of the model to d-wave meson-baryon interactions and p-wave coupling in the neglected s- and u-channel diagrams. Of several
108 citations