Exploring the dark sectors via the cooling of white dwarfs

As dense and hot bodies with a well-understood equation of state, white dwarfs offer a unique opportunity to investigate new physics. In this paper, we examine the role of dark sectors, which are extensions of the Standard Model of particle physics that are not directly observable, in the cooling process of white dwarfs. Specifically, we examine the role of a dark photon, within the framework of a three-portal model, in enhancing the neutrino emission during the cooling process of white dwarfs. We compare this scenario to the energy release predicted by the Standard Model. By analyzing the parameter space of dark sectors, our study aims to identify regions that could lead to significant deviations from the expected energy release of white dwarfs.

Figure 1

Diagrams that contribute to the plasmon decay: trough the charged and neutral currents.

Figure 2

Diagram that contributes to the plasmon decay through the dark photon.

Figure 3

Luminosity of a $1M_{\odot }$ young WD with respect to its temperature for different BSM scenarios. The solid (dashed) line represents the longitudinal (transverse) components. The green (pink) bandwidth of the DS longitudinal (transverse) contribution considers the values: $\epsilon g_D|U_D{|}^2=[{10}^{-8}-{10}^{-4}]$. The axial contribution is not just shown since no contribution comes from the new physics.

Figure 4

Luminosity of a $1M_{\odot }$ young WD with a temperature of $T={10}^8\mathrm{K}$, as a function of the dark photon mass for different BSM scenarios. The solid (dashed) line represents the longitudinal (transverse) components. The axial contribution is not shown since there is no contribution from new physics. The bandwidth of the DS contribution considers the values: $\epsilon g_D|U_D{|}^2=[{10}^{-8}-{10}^{-4}]$.

Figure 5

Limits on $\epsilon$ for dark photons decaying into neutrinos, obtained with a young WD assuming $T={10}^8\mathrm{K}$ and a dark sector parameter of $g_D|U_D{|}^2={10}^{-5}$. The luminosity due to dark photons constitutes a maximum of $F_{\mathrm{DS}}=1\%$ (lightest green shaded area), 10%, and 50% (darkest green shaded area) of the total SM luminosity. For comparison, we also show the bounds from deep-inelastic scattering (DIS) [50], electron ($g-2$) Laboratoire Kastler Brossel (LKB) [51] and electroweak precision observables (EWPOs) [52] proportioned in Ref. [19].