Cosmological implications of DESI DR2 BAO measurements in light of the latest ACT DR6 CMB data

We report cosmological results from the Dark Energy Spectroscopic Instrument (DESI) measurements of baryon acoustic oscillations (BAO) when combined with recent data from the Atacama Cosmology Telescope (ACT). By jointly analyzing ACTand Planck data and applying conservative cuts to overlapping multipole ranges, we assess how different Planck þ ACT dataset combinations affect consistency with DESI. While ACT alone exhibits a tension with DESI exceeding 3σ within the ΛCDM model, this discrepancy is reduced when ACT is analyzed in combination with Planck. For our baseline DESI DR2 BAOþPlanck PR4þACT likelihood combination, the preference for evolving dark energy over a cosmological constant is about 3σ, increasing to over 4σ with the inclusion of type Ia supernova data. While the dark energy results remain quite consistent across various combinations of Planck and ACT likelihoods with those obtained by the DESI collaboration, the constraints on neutrino mass are more sensitive, ranging from Pmν <0.061 eVinourbaseline analysis, to Pmν < 0.077 eV (95% confidence level) in the CMB likelihood combination chosen by ACT when imposing the physical prior Pmν > 0 eV.