Big Bang nucleosynthesis with long-lived strongly interacting relic particles

Abstract

Abstract. We study effects of relic long-lived strongly interacting massive particles (X particles) on big bang nucleosynthesis (BBN). The X particle is assumed to have existed during the BBN epoch, but decayed long before detected. The interaction strength between an X and a nucleon is assumed to be similar to that between nucleons. Rates of nuclear reactions and beta decay of Xnuclei are calculated, and the BBN in the presence of neutral charged X 0 particles is calculated taking account of captures of X 0 by nuclei. As a result, the X 0 particles form bound states with normal nuclei during a relatively early epoch of BBN leading to the production of heavy elements. Constraints on the abundance of X 0 are derived from observations of primordial light element abundances. Particle models which predict long-lived colored particles with lifetimes longer than ∼ 200 s are rejected. This scenario prefers the production of 9 Be and 10 B. There might, therefore, remain a signature of the X particle on primordial abundances of those elements. Possible signatures left on light element abundances expected in four different models are summarized.

On low-energy predictions of unification models inspired by F-theory

“…A colored NLSP, such as the stop [24] (∼2% in our sample), could help explain the problematic primordial abundance of lithium [25]. Although it may seem that the stop mass range required by the lithium data leads to a larger stop relic abundance than what is allowed by the Big Bang Nucleosynthesis [26], there may be additional annihilations of stops after the QCD phase transitions when the stops are in a confined phase with quarks [27,28]. The existing LHC data do not exclude a light and long-lived stop [29].…”