Revised cosmological parameters after BICEP 2 and BOSS

TL;DR

This paper analyzes how recent measurements from BICEP 2 and BOSS impact cosmological parameter estimates, finding that models with zero running of the spectral index remain consistent with other parameters when considering current neutrino mass and tensor-to-scalar ratio limits.

Contribution

It assesses the effects of BICEP 2 and BOSS data on cosmological parameters, highlighting the consistency of models with zero spectral index running with current observational constraints.

Findings

Models with zero spectral index running are consistent with current data.

Non-zero spectral index running models require higher $A_L$ values.

Current limits on neutrino mass and tensor-to-scalar ratio support standard cosmological parameters.

Abstract

Estimation of parameters of the \lq standard\rq \,model of cosmology have dramatically improved over past few decades due to increasingly exquisite measurements made by Cosmic Microwave Background (CMB) experiments. Recent data from Planck matches well with the minimal $\Lambda$CDM model. A likelihood analysis using Planck, WMAP and a selection of high resolution experiments (highL), tensor to scalar ratio $r_{0.002}$ is found to be $<0.11$ when $dn_{s}/d\ln k = 0$. Planck also imposes an upper bound on neutrino mass $\sum m_\nu<0.23\,$eV using Planck+WMAP+highL+BAO likelihood. However, recently results from BICEP 2 claims the detection of $r= 0.2^{+0.07}_{-0.05}$ from polarization spectra. Further, results from SDSS-III BOSS large scale galaxy survey constrains the total neutrino mass to $\sum m_\nu=0.36 \pm 0.10$ eV. It is important to study the consequences of these new measurements on other cosmological parameters. In this paper we assess the revised constraints on cosmological parameters in light of these two measurements that are in some tension with the constraints from Planck. Using the prior on $\sum m_\nu$ as measured by SDSS-III BOSS and BICEP 2 likelihood, we find that the model with running spectral index ($dn_{s}/d\ln k \neq 0$) leads to a value of $A_L>1$ at $3.1 \sigma$. But, the model with $dn_{s}/d\ln k =0$ makes $A_L$ consistent with $1$, at $2.1\sigma$ and also shows that $N_{\rm eff}$ is consistent with its theoretical value of $3.046$ at around $2\sigma$. Therefore, the analysis in this paper shows that the model with $dn_{s}/d\ln k =0$ gives consistency with other cosmological parameters ($N_{\rm eff}$ and $A_L$ ) when the current limits on $\sum m_\nu$ and $r_{0.05}$ are considered. However, on reducing the value of $r_{0.05}$, the model with non-zero $dn_{s}/d\ln k$ gives consistent result of $A_L =1$ [abridged].