Testing CCDM Cosmology with the Radiation Temperature-Redshift Relation
  The standard $\Lambda$CDM model can be mimicked at the background and
perturbative levels (linear and non-linear) by a class of gravitationally
induced particle production cosmology dubbed CCDM cosmology. However, the
radiation component in the CCDM model follows a slightly different
temperature-redshift $T(z)$-law which depends on an extra parameter, $\nu_r$,
describing the subdominant photon production rate. Here we perform a
statistical analysis based on a compilation of 36 recent measurements of $T(z)$
at low and intermediate redshifts. The likelihood of the production rate in
CCDM cosmologies is constrained by $\nu_r = 0.024^{+0.026}_{-0.024}$ ($1\sigma$
confidence level), thereby showing that $\Lambda$CDM ($\nu_r=0$) is still
compatible with the adopted data sample. Although being hardly differentiated
in the dynamic sector (cosmic history and matter fluctuations), the so-called
thermal sector (temperature law, abundances of thermal relics and CMB power
spectrum) offers a clear possibility for crucial tests confronting $\Lambda$CDM
and CCDM cosmologies.
