Resonant annihilation of long-lived massive colored particles through hadronic collisions

TL;DR

This paper investigates how long-lived massive colored particles could annihilate through resonant hadronic collisions, affecting early universe element abundances and providing insights into the quark-hadron phase transition.

Contribution

It introduces a toy model for the resonant annihilation process of MCPs and explores how resonance properties influence relic abundances of SIMPs in the early universe.

Findings

Relic abundances of SIMPs are estimated to be 2 x 10^{-8} to 3 x 10^{-4} times the baryon abundance.

Resonant annihilation can significantly alter primordial light element abundances.

The results suggest potential connections between MCP annihilation and observed light element anomalies.

Abstract

Hypothetical long-lived massive colored particles (MCPs or Ys) would be confined in colorless exotic strongly interacting massive particles (SIMPs) at color confinement temperature of T_C /sim 200 MeV. Two long-lived MCPs form a bound state (Y /bar{Y}) at collisions of two SIMPs. We study sensitivities of MCP annihilation to decay properties of resonances (Y /bar{Y}), and binding energies or energy levels of exotic SIMPs. The (Y /bar{Y}) formation is assumed to dominantly proceeds through resonances of (Y/bar{Y}) in this paper. We make a toy model of the effective cross section for Y /bar{Y} annihilation. Abundances of SIMPs are then calculated for different sets of parameters specifying properties of (Y /bar{Y}) resonances, binding energies of SIMPs, the initial abundance and the mass of MCP. Calculated relic abundances for respective SIMP species are 2 x 10^{-8}--3 x 10^{-4} times that of baryon. They can be much higher but cannot be much smaller than the previous estimate. The abundances can be consistent depending on parameters with the possible scenario that SIMPs bind to nuclei and subsequent exotic nuclear reactions reduce the primordial abundance of 7Li or enhance those of 9Be and/or B in the early universe. A unique information on the quark-hadron phase transition in the early universe may become available in future by elaborated studies on the annihilation process with light element abundances as observables.