Vacuum Cherenkov radiation for Lorentz-violating fermions

Abstract

The current work focuses on the process of vacuum Cherenkov radiation for Lorentz-violating fermions that are described by the minimal Standard-Model Extension (SME). To date, most considerations of this important hypothetical process have been restricted to Lorentz-violating photons, as the necessary theoretical tools for the SME fermion sector have not been available. With their development in a very recent paper, we are now in a position to compute the decay rates based on a modified Dirac theory. Two realizations of the Cherenkov process are studied. In the first scenario, the spin projection of the incoming fermion is assumed to be conserved, and in the second, the spin projection is allowed to flip. The first type of process is shown to be still forbidden for the dimensionful $a$ and $b$ coefficients where there are strong indications that it is energetically disallowed for the $H$ coefficients, as well. However, it is rendered possible for the dimensionless $c$, $d$, $e$, $f$, and $g$ coefficients. For large initial fermion energies, the decay rates for the $c$ and $d$ coefficients were found to grow linearly with momentum and to be linearly suppressed by the smallness of the Lorentz-violating coefficient where for the $e$, $f$, and $g$ coefficients this suppression is even quadratic. The decay rates vanish in the vicinity of the threshold, as expected. The decay including a fermion spin flip plays a role for the spin-nondegenerate operators and it was found to occur for the dimensionful $b$ and $H$ coefficients as well as for the dimensionless $d$ and $g$. The characteristics of this process differ much from the properties of the spin-conserving one, e.g., there is no threshold. Based on experimental data of ultra-high-energy cosmic rays, new constraints on Lorentz violation in the quark sector are obtained from the thresholds.

59 pages, 6 figures, final version matching article published in Phys. Rev. D

References in corpus (19)

• Quantum Gravity at a Lifshitz Point
• Electrodynamics with Lorentz-violating operators of arbitrary dimension
• Matter-gravity couplings and Lorentz violation
• Vacuum Cerenkov Radiation in Lorentz-Violating Theories Without CPT Violation
• Lorentz-violating spinor electrodynamics and Penning traps
• A new CPT-even and Lorentz-Violating nonminimal coupling in the Dirac equation
• Limits on isotropic Lorentz violation in QED from collider physics
• Bounds on length scales of classical spacetime foam models
• Cerenkov Radiation in a Lorentz-Violating and Birefringent Vacuum
• Vacuum Cherenkov radiation in spacelike Maxwell-Chern-Simons theory
• Eliminating the CPT-Odd f Coefficient from the Lorentz-Violating Standard Model Extension
• Restrictions from Lorentz invariance violation on cosmic ray propagation
• Weighted power counting, neutrino masses and Lorentz violating extensions of the Standard Model
• Lorentz-violating modification of Dirac theory based on spin-nondegenerate operators
• Covariant Quantization of CPT-violating Photons
• Vacuum Cherenkov Radiation In Quantum Electrodynamics With High-Energy Lorentz Violation
• Absence of Long-Wavelength Cerenkov Radiation With Isotropic Lorentz and CPT Violation
• Vacuum Cherenkov radiation and photon decay rates from generic Lorentz Invariance Violation
• CPT-Violating, Massive Photons and Cherenkov Radiation

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