Raising the Optical Depth to Reionization with Dark Matter Decay
The study investigates if dark matter decay can explain a higher reionization optical depth ($ au_{reio} eq 0.06$) suggested by recent DESI measurements, which prefer $ au_{reio} allingdotseq 0.09$. By modeling the extra ionization caused by decaying dark matter through a Gompertzian reionization model, the researchers found that while decay increases $ au_{reio}$ to about 0.072 for $m_{\chi}=1$ GeV, it does not significantly improve the fit to all cosmological data.