text:   Microwave Background",3,"['Do you wonder about CMB+BAO constraints on self-interacting neutrinos if only some of them self-interact? We studied a bunch of examples in this paper led by Thejs Brinckmann. Major congrats to Thejs @ThejsBrinckmann and Jae Hyeok Chang on this nice work! \n<LINK>', 'Some punchlines: we find no strong evidence for self-interactions or larger/smaller values of Neff. On the other hand, there are some additional modes in parameter space with neutrinos decoupling much later than SM ones should, but they are not preferred.', 'We also weigh in on the H0 tension and find (as others have!), that self-interacting neutrinos are not a solution unless you throw out high-ell CMB polarization data, which we have no reason to do. Interestingly, if you did throw it out we found H0 = 74 km/s/Mpc.']",20,12,782