Updated Constraints on Large Extra Dimensions from Reactor Antineutrino Experiments

We investigate constraints on large extra dimensions (LED) using the latest results from reactor antineutrino experiments. Specifically, we analyze the full data sets from Daya Bay, RENO, KamLAND, NEOS, and STEREO to derive updated bounds. For the case of one extra dimension, we find constrains on its radius $a$ of $a \lesssim 0.58~{\rm \mu m}$ ($a \lesssim 0.12~{\rm \mu m}$) at the $99\%$ confidence level for normal (inverted) ordering, an improvement of approximately $\sim 20\%$ ($\sim 25\%$) with respect to previous bounds, assuming a massless lightest active neutrino. Furthermore, we present new limits on $4+d$ LED scenarios, with $d = 2, 3, 4$ denoting the number of extra dimensions, based on the same reactor data and assuming equal radii for all extra dimensions. We find that the constraints become increasingly stringent with a larger number of extra dimensions. In particular, $d = 4$ with a massless lightest active neutrino, we obtain limits of $a \lesssim 0.28~{\rm \mu m}$ for normal and $a \lesssim 0.05~{\rm \mu m}$ for inverted orderings at the $99\%$ confidence level.