Hidden Photon Compton and Bremsstrahlung in White Dwarf Anomalous Cooling and Luminosity Functions

TL;DR

This paper investigates how a hidden photon could influence white dwarf cooling and luminosity functions, providing constraints on the hidden photon properties through observational data analysis.

Contribution

It introduces a detailed calculation of hidden photon effects on white dwarf cooling and luminosity functions, and compares these with observational data to constrain model parameters.

Findings

Compatible results for hidden photon mass with SDSS and SuperCOSMOS data.

Stringent limits on kinetic mixing parameter $psilon$ derived.

WDLF analysis supports the anomalous cooling rate findings.

Abstract

We computed the contribution of the Compton and Bremsstrahlung processes with a hidden light $U(1)_D$ neutral boson $\gamma_D$ to the white dwarf G117-B15A anomalous cooling rate, as well as the white dwarf luminosity functions (WDLF). We demonstrated that for a light mass of hidden photon ($m_{\gamma_D} \ll$ a few keV), compatible results are obtained for the recent Sloan Digital Sky Survey and the SuperCOSMOS Sky Survey observation, but the stringent limits would be imposed on the kinetic mixing $\epsilon$. We performed $\chi^2$-tests to acquire a quantitative assessment on the WDLF data in the context of our model, computed under the assumption of different kinetic mixing $\epsilon$, the age of the oldest computed stars $T_D$, and a constant star formation rate $\psi$. Then taken together, the WDLF analysis of 2$\sigma$ confidence interval $\epsilon = \left( 0.37^{+0.35}_{-0.37}\right) \times 10^{-14}$ is barely consistent with the cooling rate analysis at 2$\sigma$ regime $\epsilon = \left( 0.97^{+0.35}_{-0.37} \right) \times 10^{-14}$. The two approaches used here agree with each other in yielding an anomalous cooling rate of white dwarf in this luminosity range.