Work

CMB Injection Bounds on Moduli Fields

Year: 2026

Type: preprint

Abstract: Light scalar fields with gravitational strength interactions (moduli) are ubiquitous in string, supergravity, and extra-dimensional models. If produced in the early universe with lifetimes exceeding the epoch of recombination, slowly decaying moduli inject energetic particles into the Standard Model plasma, leaving distinct imprints on the cosmic microwave background (CMB). In this paper we systematically derive CMB injection bounds on light moduli ($10^3\ {\rm eV}\leq m_{\rm{mod}}\leq 10^8\ {\rm eV}$) across the primary cosmological production channels: vacuum misalignment, heavy scalar/inflaton decay, thermal emission from the primordial plasma including production from a Hagedorn phase of hot strings. We show that these injection bounds impose stringent constraints that are complementary to both the standard cosmological moduli problem and fifth force bounds.

Source: arXiv (Cornell University)

DOI: 10.48550/arxiv.2609.38151

Authors: Agarwal, Naman, Frey, Andrew R., Mahanta, Ratul, Maharana, Anshuman, Quevedo, Fernando, Villa, Gonzalo

Institutions: University of Manitoba, Winnipeg Institute for Theoretical Physics, The University of Winnipeg, University of Science and Technology of China, Peng Huanwu Center for Fundamental Theory, New York University Abu Dhabi, University of Cambridge, University of Michigan

Language: English

Topic: Cosmology and Gravitation Theories

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: New York University Abu Dhabi, National Natural Science Foundation of China, Tamkeen, Natural Sciences and Engineering Research Council of Canada

Awards: G2012042336, G2693235065, G7821892606

OpenAlex ID: W7214924051

Cites: 24

Cited by: 1

Related to: 10