scholarly journals Salvage of too slow gravitinos

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
I. Antoniadis ◽  
K. Benakli ◽  
W. Ke
Keyword(s):  
Dispersion Relation ◽  
Sound Speed ◽  
Longitudinal Mode ◽  
Lorentz Symmetry ◽  
Cosmological Models ◽  
Relativistic Dispersion

Abstract Gravitinos can inherit a non-relativistic dispersion relation while propagating in a background breaking both supersymmetry and Lorentz symmetry spontaneously. This is because the longitudinal mode velocity is controlled by the sound speed in the background. It was pointed out recently by Kolb, Long and McDonough that the production of gravitinos might diverge when this sound speed vanishes. We argue that in the framework of cosmological models with linearly spontaneously broken realised supersymmetry, where the physical fermions are combinations of the vacuum goldstino and the inflatino, the gravitino longitudinal mode has a relativistic dispersion relation and therefore avoids the catastrophic production. We illustrate this in some explicit examples.

Ion-cyclotron modes in weakly relativistic plasmas

1994 ◽  
Vol 51 (3) ◽  
pp. 371-379 ◽  
Author(s):  
Chandu Venugopal ◽  
P. J. Kurian ◽  
G. Renuka
Keyword(s):  
Dispersion Relation ◽  
High Frequency ◽  
Low Frequency ◽  
Dispersion Relations ◽  
The Other ◽  
Larmor Radius ◽  
Relativistic Plasmas ◽  
Ion Plasma ◽  
Maxwellian Plasma ◽  
Relativistic Dispersion

We derive a dispersion relation for the perpendicular propagation of ioncyclotron waves around the ion gyrofrequency ω+ in a weaklu relaticistic anisotropic Maxwellian plasma. These waves, with wavelength greater than the ion Larmor radius rL+ (k⊥ rL+ < 1), propagate in a plasma characterized by large ion plasma frequencies (). Using an ordering parameter ε, we separated out two dispersion relations, one of which is independent of the relativistic terms, while the other depends sensitively on them. The solutions of the former dispersion relation yield two modes: a low-frequency (LF) mode with a frequency ω < ω+ and a high-frequency (HF) mode with ω > ω+. The plasma is stable to the propagation of these modes. The latter dispersion relation yields a new LF mode in addition to the modes supported by the non-relativistic dispersion relation. The two LF modes can coalesce to make the plasma unstable. These results are also verified numerically using a standard root solver.

scholarly journals Non-Hermitian Lagrangian for Quasirelativistic Fermions

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Jean Alexandre
Keyword(s):  
Dispersion Relation ◽  
Lorentz Symmetry ◽  
Mass Scale ◽  
Free Fermions ◽  
Intermediate Regime

We present a Lorentz-symmetry violating Lagrangian for free fermions, which is local but not Hermitian, whereas the corresponding Hamiltonian is Hermitian but not local. A specific feature of the model is that the dispersion relation is relativistic in both the IR and the UV but not in an intermediate regime, set by a given mass scale. The consistency of the model is shown by the study of properties expected in analogy with the Dirac Lagrangian.

scholarly journals Superluminal Accelerations Along a Helically Twisted Jet

1988 ◽  
Vol 129 ◽  
pp. 87-88
Author(s):  
Philip E. Hardee
Keyword(s):  
Dispersion Relation ◽  
Supersonic Jet ◽  
Spatial Growth ◽  
Relativistic Dispersion

The relativistic dispersion relation describing the spatial growth of a helical perturbation to a relativistic supersonic jet is applied to observations of the nonlinear superluminal acceleration of component C4 along the inner jet in 3C345.

Non-Relativistic Dispersion Relations for a Two Channel Scattering Process

1962 ◽  
Vol 58 (2) ◽  
pp. 363-376 ◽  
Author(s):  
J. Underhill
Keyword(s):  
Fourier Transform ◽  
Dispersion Relation ◽  
Scattering Amplitude ◽  
Bound State ◽  
Potential Scattering ◽  
Scattering Process ◽  
Relativistic Dispersion ◽  
The Fourier Transform ◽  
Image Position ◽  
Relativistic Potential

In (l) Khuri has proved the validity of a dispersion relation for non-relativistic potential scattering. More precisely, he has shown that if the potential V(r) is central and satisfies: then the scattering amplitude f(k, τ) = M(E, τ) (where E = k2 is the energy) satisfies the following dispersion relation for fixed momentum transfer τ ≤ 2α: In (2), Rj(τ) is the (real) residue of the scattering amplitude at the bound state Ej and is the Fourier transform of the potential .

scholarly journals On the Majorana Equation: Relations between Its Complex Two-Component and Real Four-Component Eigenfunctions

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Eckart Marsch
Keyword(s):  
Dispersion Relation ◽  
Dirac Equation ◽  
Massive Particle ◽  
Mass Term ◽  
Complex Conjugation ◽  
Conjugation Operator ◽  
Direct Linearization ◽  
Two Component ◽  
Relativistic Dispersion ◽  
Component Spinor

We first derive without recourse to the Dirac equation the two-component Majorana equation with a mass term by a direct linearization of the relativistic dispersion relation of a massive particle. Thereby, we make only use of the complex conjugation operator and the Pauli spin matrices, corresponding to the irreducible representation of the Lorentz group. Then we derive the complex two-component eigenfunctions of the Majorana equation and the related quantum fields in a concise way, by exploiting the so-called chirality conjugation operator that involves the spin-flip operator. Subsequently, the four-component spinor solutions of the real Majorana equation are derived, and their intrinsic relations with the spinors of the complex two-component version of the Majorana equation are revealed and discussed extensively.

scholarly journals Relativistic Dispersion Relation Approach to Photomeson Production

1957 ◽  
Vol 106 (6) ◽  
pp. 1345-1355 ◽  
Author(s):  
G. F. Chew ◽  
M. L. Goldberger ◽  
F. E. Low ◽  
Y. Nambu
Keyword(s):  
Dispersion Relation ◽  
Relativistic Dispersion ◽  
Relation Approach

scholarly journals AN INVESTIGATION INTO THE FERMILAB APPROACH TO HEAVY QUARKS ON THE LATTICE

2001 ◽  
Vol 16 (supp01c) ◽  
pp. 1231-1233
Author(s):  
ZBIGNIEW SROCZYNSKI
Keyword(s):  
Dispersion Relation ◽  
Heavy Quarks ◽  
Space Time ◽  
Matrix Elements ◽  
Relativistic Dispersion ◽  
The Asymmetry ◽  
Light Mesons ◽  
Fermion Action

We use a space-time asymmetric O(a) improved fermion action and fix the asymmetry non-perturbatively to restore the relativistic dispersion relation. We compute spectra and matrix elements of quarkonia and heavy-light mesons and compare with results obtained using a symmetric action with the Fermilab interpretation i.e. that the physics of heavy lattice quarks depends solely on their kinetic mass. We provide additional evidence to support this.

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