New results of the search for hidden photons by means of a multicathode counter

TL;DR

This study sets new upper limits on hidden photon mixing parameters in the 5 eV to 10 keV mass range using a multicathode counter, observing a potential spontaneous electron emission effect independent of temperature.

Contribution

It provides the first experimental upper limits on hidden photon mixing in the 5 eV to 10 keV range using a multicathode counter and reports a statistically significant spontaneous electron emission effect.

Findings

Upper limit on mixing parameter less than 4 x 10^-11 for 10 eV to 30 eV range

Observed a positive effect of spontaneous electron emission at over 7σ significance

Temperature dependence suggests thermal emission from copper cathode is negligible

Abstract

New upper limit on a mixing parameter for hidden photons with a mass from 5 eV till 10 keV has been obtained from the results of measurements during 78 days in two configurations R1 and R2 of a multicathode counter. For a region of a maximal sensitivity from 10 eV till 30 eV the upper limit obtained is less than 4 x 10-11. The measurements have been performed at three temperatures: 26C, 31C and 36C. A positive effect for the spontaneous emission of single electrons has been obtained at the level of more than 7{\sigma}. A falling tendency of a temperature dependence of the spontaneous emission rate indicates that the effect of thermal emission from a copper cathode can be neglected.