Probing P and CP violations on the cosmological collider

Abstract

In direct analogy to the 4-body decay of a heavy scalar particle, the 4-point correlation function of primordial fluctuations carries P and CP information. The CP violation appears as a P-odd angular dependence in the imaginary part of the trispectrum in momentum space. We construct a model with axion-like couplings which leads to observably large CP-violating trispectrum for future surveys. Furthermore, we show the importance of on-shell particle production in observing P-and CP-violating signals. It is impossible to observe these signals from local 4-scalar EFT operators that respect dS isometries, and thus any such observation can rule out single-field EFT with sufficiently small slow-roll parameters. This calculation opens a new frontier of studying P and CP at very high energy scales. * Electronic address: taoliu@ust.hk † Electronic address: xtongac@connect.ust.hk ‡ Electronic address: phyw@ust.hk § Electronic address:

The Cosmological Bootstrap: Spinning correlators from symmetries and factorization

“…Our hope is to learn similar lessons in the cosmological setting. 36 In this paper, we will focus mainly on cosmological correlators for which a consistent four-particle amplitude is known to exist. The case of no-go results and exotic representations, unique to de Sitter space, will be considered elsewhere.…”

Cosmological collider signatures of massive vectors from non-Gaussian gravitational waves

“…. This enhancement effect caused by the chemical potential can be easily seen from the IR (|kτ | → 0) limit of the mode function [37]…”

“…However, ξ cannot be too large so that the back-reaction to the inflation background is small. The constraint of the massless case is given by [29], as for massive vector fields case see [37]. In [37], the mass is relatively small thus the mass term on the index is ignored.…”

“…For example, in axion inflation model the pseudo-scalar inflaton φ is generically coupled to U(1) gauge field through the interaction L = φ 4fF µν F µν which can generate exponentially amplified of gauge particles. In the context of cosmological collider physics, the Fermionic case was studied in [36] and the Bosonic case was studied in [37]. For a systematic study, see [38].…”

Chemical-potential-assisted particle production in FRW spacetimes

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