Constraining Neutrino Cooling Using the Hot White Dwarf Luminosity Function in the Globular Cluster 47 Tucanae

We present Hubble Space Telescope observations of the upper part({T}{eff}\gt {10}4 K) of the white dwarf coolingsequence in the globular cluster 47 Tucanae and measure a luminosityfunction of hot white dwarfs. Comparison with previous determinationsfrom large-scale field surveys indicates that the previously determinedplateau at high effective temperatures is likely a selection effect, asno such feature is seen in this sample. Comparison with theoreticalmodels suggests that the current estimates of white dwarf neutrinoemission (primarily by the plasmon channel) are accurate, and variations