We update constraints on cosmic opacity by combining recent SN Type Ia data compilation with the latest measurements of the Hubble expansion at redshifts between 0 and 2 .
The new constraint on the parameter \epsilon parametrising deviations from the luminosity-angular diameter distance relation ( d _ { L } = d _ { A } ( 1 + z ) ^ { 2 + \epsilon } ) , is \epsilon = -0.04 _ { -0.07 } ^ { +0.08 } ( 2- \sigma ) .
For the redshift range between 0.2 and 0.35 this corresponds to an opacity \Delta \tau < 0.012 ( 95 \% C.L .
) , a factor of 2 stronger than the previous constraint .
Various models of beyond the standard model physics that predict violation of photon number conservation contribute to the opacity and can be equally constrained .
In this paper we put new limits on axion-like particles , including chameleons , and mini-charged particles .