### Speaker

### Description

Spectral distortions of the CMB provide independent and complementary probes to study energy injection processes in the early universe. In this work was obtained the spectral $\mu$-distortion associated with phase transition of the dark particles in the BDM model. Several scenarios were simulated numerically with parameters: $a_{c} = [4.9 \times 10^{-7}, 3.3 \times 10^{-6}]$, $ f_{eff} = [0,1]$, $v_{c}=[0,0.71]$, $f_{x}=$ $ 10^{-2}$, $ 10^{-3}$, $10^{-4}$, $10^{-5}$ and $10^{-6}$. Some constrictions were obtained for FIRAS sensivity for $ a_{c} < 1.68 \times 10^{-6} $ ($ f_{x} = 10^{-2}$, $ f_{eff} = 0.5 $) and for PIXIE sensivity $ a_{c} > 1 \times 10^{-6} $ ($ f_{x} = 10^{-5} $, $ f_{eff} = 0.5 $).