Hadronic Decay of Late-Decaying Particles and Big-Bang Nucleosynthesis

Abstract

We study the big-bang nucleosynthesis (BBN) scenario with late-decaying exotic particles with lifetime longer than $\sim 1$ sec. With a late-decaying particle in the early universe, predictions of the standard BBN scenario can be significantly altered. Therefore, we derive constraints on its primordial abundance. We pay particular attention to hadronic decay modes of such particles. We see that the non-thermal production process of D, ${\rm ^{3}He}$ and ${\rm ^6Li}$ provides a stringent upper bound on the primordial abundance oflate-decaying particles with hadronic branching ratio.

Figures (2)

• Figure 1: Upper bounds on $m_X Y_X$ as a function of $\tau_X$ at 95% C.L. for the case of $B_{\rm h}=10^{-3}$. The name of the element which gives the constraint is written by each line. We assume that two hadron jets are produced by single decay of $X$ with the energy $E_{\rm jet} = m_{X}/2$. Here we consider $m_{X}=\epsilon_{X}=1\ {\rm TeV}$. Note that $Y_X = n_{X}/s$.
• Figure 2: Same as Fig. \ref{['fig:SmallBh']}, except for $B_{\rm h}=1$.