http://arxiv.org/abs/1711.09929
New interactions of neutrinos can stop these from free streaming in the early Universe even after the weak decoupling epoch. This results in the enhancement of primordial gravitational wave amplitude on small scales compared to the standard $\Lambda$CDM prediction. In this paper we calculate the effect of dark matter neutrino interactions in CMB tensor $B$-mode spectrum. We show that the effect of new neutrino interactions generates a scale or $\ell$ dependent imprint in the CMB $B$-mode power spectrum at $\ell \gtrsim 100$. In the event that primordial $B$-modes are detected by future experiments, a departure from scale invariance, with a blue spectrum, may not necessarily mean failure of simple inflationary models but instead may be a sign of non-standard interactions of relativistic particles. There is rich information hidden in the CMB $B$-mode spectrum beyond just the tensor to scalar ratio.
S. Ghosh, R. Khatri and T. Roy
Wed, 29 Nov 17
42/69
Comments: N/A
You must be logged in to post a comment.