Constraining Cut-off Physics in the Cosmic Microwave Background

TL;DR

This paper examines how well current and future cosmic microwave background data can detect oscillatory features in the primordial power spectrum caused by physics at the cut-off energy scale, finding current data limits and future prospects.

Contribution

It provides the first detailed analysis of the constraints on oscillatory features from the cut-off physics in the primordial spectrum using WMAP data and forecasts for cosmic variance limited experiments.

Findings

Current data constrains oscillation amplitude to less than 0.77 at 2-sigma.

Future experiments could constrain amplitude below 0.005.

Oscillations from physics at Lambda>200 H_infl are unobservable with CMB.

Abstract

We investigate the ability to constrain oscillatory features in the primordial power spectrum using current and future cosmic microwave background observations. In particular, we study the observability of an oscillation arising from imprints of physics at the cut-off energy scale. We perform a likelihood analysis on the WMAP data set, and find that the current data set constrains the amplitude of the oscillations to be less than 0.77 at 2-sigma, consistent with a power spectrum without oscillations. In addition, we investigate the fundamental limitations in the measurement of oscillation parameters by studying the constraints from a cosmic variance limited experiment. We find that such an experiment is capable of constraining the amplitude of such oscillations to be below 0.005, implying that reasonable models with cut-off energy scales Lambda>200 H_infl are unobservable through the microwave background.