Constraints from Solar and Reactor Neutrinos on Unparticle Long-Range Forces

TL;DR

This paper explores how unparticle-induced long-range forces affect solar neutrino oscillations, setting stringent limits on unparticle parameters and coupling non-universality based on neutrino data.

Contribution

It provides novel constraints on unparticle physics parameters by analyzing their effects on solar neutrino oscillations and KamLAND data.

Findings

Severe limits on the unparticle scale Lambda_u and new physics scale M.

Constraints depend on the unparticle dimension d and ultraviolet dimension d_UV.

Bounds suggest potential for future collider tests of fermion-unparticle couplings.

Abstract

We have investigated the impact of long-range forces induced by unparticle operators of scalar, vector and tensor nature coupled to fermions in the interpretation of solar neutrinos and KamLAND data. If the unparticle couplings to the neutrinos are mildly non-universal, such long-range forces will not factorize out in the neutrino flavour evolution. As a consequence large deviations from the observed standard matter-induced oscillation pattern for solar neutrinos would be generated. In this case, severe limits can be set on the infrared fix point scale, Lambda_u, and the new physics scale, M, as a function of the ultraviolet (d_UV) and anomalous (d) dimension of the unparticle operator. For a scalar unparticle, for instance, assuming the non-universality of the lepton couplings to unparticles to be of the order of a few per mil we find that, for d_UV=3 and d=1.1, M is constrained to be M > O(10^9) TeV (M > O(10^10) TeV) if Lambda_u= 1 TeV (10 TeV). For given values of Lambda_u and d, the corresponding bounds on M for vector [tensor] unparticles are approximately 100 [3/Sqrt(Lambda_u/TeV)] times those for the scalar case. Conversely, these results can be translated into severe constraints on universality violation of the fermion couplings to unparticle operators with scales which can be accessible at future colliders.