arXiv subjects

Martina Taiuti

Publications and source records attributed to Martina Taiuti.

3 recordsLinked to original sources

arXiv2011

Vacuum Cherenkov Radiation In Quantum Electrodynamics With High-Energy Lorentz Violation

We study phenomena predicted by a renormalizable, CPT invariant extension of the Standard Model that contains higher-dimensional operators and violates Lorentz symmetry explicitly at energies greater than some scale Lambda_{L}. In particular, we consider the Cherenkov radiation in vacuo. In a rather general class of dispersion relations, there exists an energy threshold above which radiation is emitted. The threshold is enhanced in composite particles by a sort of kinematic screening mechanism. We study the energy loss and compare the predictions of our model with known experimental bounds on Lorentz violating parameters and observations of ultrahigh-energy cosmic rays. We argue that the scale of Lorentz violation Lambda_{L} (with preserved CPT invariance) can be smaller than the Planck scale, actually as small as 10^{14}-10^{15} GeV. Our model also predicts the Cherenkov radiation of neutral particles.

hep-ph↗

arXiv2010

Renormalization Of High-Energy Lorentz Violating QED

We study a QED extension that is unitary, CPT invariant and super-renormalizable, but violates Lorentz symmetry at high energies, and contains higher-dimension operators (LVQED). Divergent diagrams are only one- and two-loop. We compute the one-loop renormalizations at high and low energies and analyse the relation between them. It emerges that the power-like divergences of the low-energy theory are multiplied by arbitrary constants, inherited by the high-energy theory, and therefore can be set to zero at no cost, bypassing the hierarchy problem.

hep-ph↗

arXiv2001

Diffusion corrections to the hard pomeron

The high-energy behaviour of two-scale hard processes is investigated in the framework of small-x models with running coupling, having the Airy diffusion model as prototype. We show that, in some intermediate high-energy regime, the perturbative hard Pomeron exponent determines the energy dependence, and we prove that diffusion corrections have the form hinted at before in particular cases. We also discuss the breakdown of such regime at very large energies, and the onset of the non-perturbative Pomeron behaviour.

hep-ph↗