2016/04/30 by Joe Sato, Takashi Shimomura, Masato Yamanaka
Computer Science · Physics and Astronomy · #Computational Physics and Python Applications #Lightest Supersymmetric Particle #Minimal Supersymmetric Standard Model #Neutralino #Neutrino Physics Research #Nucleosynthesis #Parameter space #Particle physics theoretical and experimental studies #Space (punctuation) #Superpartner #Supersymmetry #Upper and lower bounds #astro-ph.CO #hep-ph
paper · pdf · doi:10.1142/s0218301317410051
28 pages, 12 figures. v2: references added
arxiv created 2016/05/23 · openalex created_date 2016/06/24 · openalex publication_date 2017/08/01 · arxiv updated 2017/09/20 · openalex updated_date 2026/08/05
We review a nonstandard Big-Bang Nucleosynthesis (BBN) scenario within the minimal supersymmetric standard model, and propose an idea to solve both the [Formula: see text] and [Formula: see text] problems. Each problem is a discrepancy between the predicted abundance in the standard BBN and observed one. We focus on the stau, a supersymmetric partner of tau lepton, which is a long-lived charged particle when it is the next lightest supersymmetric particle and is degenerate in mass with the lightest supersymmetric particle. The long-lived stau forms a bound state with a nucleus, and provides nonstandard nuclear reactions. One of those, the internal conversion process, accelerates the destruction of [Formula: see text] and [Formula: see text], and leads to a solution to the [Formula: see text] problem. On the other hand, the bound state of the stau and [Formula: see text] enhances productions of n, D, T and [Formula: see text]. The over-production of [Formula: see text] could solve the [Formula: see text] problem; while the over-productions of D and T could conflict with observations, and hence the relevant parameter space of the stau is strictly constrained. We therefore need to carefully investigate the stau–[Formula: see text] bound state to find a condition of solving the [Formula: see text] problem. The scenario of the long-lived stau simultaneously and successfully fits the abundances of light elements (D, T, [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]) and the neutralino dark matter to the observed ones. Consequently, the parameter space both of the stau and the neutralino is determined with excellent accuracy.