Constraints on vector unparticle physics from cosmic censorship

TL;DR

This paper uses cosmic censorship to constrain vector unparticle couplings, deriving limits that are especially strict for low-mass black holes and estimating the minimal black hole mass in the unparticle framework.

Contribution

It introduces a novel method to constrain unparticle physics parameters using cosmic censorship and analyzes the implications for black hole formation.

Findings

Constraints on unparticle coupling $\lambda$ from cosmic censorship.

Stricter bounds for low-mass black holes compared to other methods.

Estimation of the minimal black hole mass in unparticle physics.

Abstract

Vector unparticle couplings to standard model fields produce repulsive corrections to gravity. From a general relativistic perspective, this leads to an effective Reissner-Nordstr\"om-like metric whose "charge" is a function of the unparticle coupling constant $\lambda$, and therefore can admit naked singularities. Requiring the system to respect cosmic censorship provides a new method of constraining the value of $\lambda$. These limits are extremely loose for stellar-mass black holes, but commensurate with existing bounds for primordial black holes. In the case of theoretical low-mass black holes, the bounds on $\lambda$ are much stricter than those derived from astrophysical and accelerator phenomenology. Additional constraints on the lower limit of $\lambda$ are used to estimate the mass of the smallest possible black hole $\Mbh^{\rm min}$ that can be formed in the unparticle framework, as a function of the unparticle parameters ($\Lambda_\unp,M_\unp,\du,\dbz$).