New constraints on radiative decay of long-lived particles in big bang nucleosynthesis with newHe4photodisintegration data

Abstract

A recent measurement of 4 He photodisintegration reactions, 4 He(γ,p) 3 H and 4 He(γ,n) 3 He with laser-Compton photons shows smaller cross sections than those estimated by other previous experiments at Eγ < ∼ 30 MeV. We study big-bang nucleosynthesis with the radiative particle decay using the new photodisintegration cross sections of 4 He as well as previous data. The sensitivity of the yields of all light elements D, T, 3 He, 4 He, 6 Li, 7 Li and 7 Be to the cross sections is investigated. The change of the cross sections has an influence on the non-thermal yields of D, 3 He and 4 He. On the other hand, the non-thermal 6 Li production is not sensitive to the change of the cross sections at this low energy, since the non-thermal secondary synthesis of 6 Li needs energetic photons of Eγ > ∼ 50 MeV. The non-thermal nucleosynthesis triggered by the radiative particle decay is one of candidates of the production mechanism of 6 Li observed in metal-poor halo stars (MPHSs). In the parameter region of the radiative particle lifetime and the emitted photon energy which satisfies the 6 Li production above the abundance level observed in MPHSs, the change of the photodisintegration cross sections at Eγ < ∼ 30 MeV as measured in the recent experiment leads to ∼ 10 % reduction of resulting 3 He abundance, whereas the 6 Li abundance does not change for this change of the cross sections of 4 He(γ,p) 3 H and 4 He(γ,n) 3 He. The 6 Li abundance, however, could show a sizable change and therefore the future precise measurement of the cross sections at high energy Eγ > ∼ 50 MeV is highly required.

Revisiting big-bang nucleosynthesis constraints on long-lived decaying particles

“…It has been well recognized that, if there exists new physics beyond the standard model which may induce non-standard BBN reactions, the predictions of the SBBN change. #1 In particular, with long-lived unstable particles decaying into electromagnetic [13,14,15,16,17,18,19,20] or hadronic [21,22,23,24,25,26,27,28,29,30,31,32] particles, the light element abundances are affected by photodissociation, hadrodissociation, and p ↔ n conversion processes. In order not to spoil the agreement between theoretical predictions and observational constraints, upper bounds on the primordial abundances of the unstable particles are obtained.…”

Cosmic rays during BBN as origin of Lithium problem

“…Neutrons are hard to accelerate for electric neutrality, and electrons are out of consideration in SBBN computation, so we focus on nuclei. Because Helium loses energy more quickly through Coulomb scattering [38,41,42] due to the higher nuclear electric charge [43], we exclude 3 He and 4 He as the components of BBNCRs. We assume that BBNCRs consist of energetic hydrogens, namely protons, deuterons and tritones.…”

Influence of gamma-ray emission on the isotopic composition of clouds in the interstellar medium

“…The dots indicate the experimental data: T(γ, n) D Varfolomeev and Gorbunov (1965), Bosch et al (1964), Skopik et al (1981), Faul et al (1981); T(γ, 2n)p Faul et al (1980). 3 He(γ, p) D Ticcioni et al (1973), Stewart et al (1965), Warren et al (1963), Naito et al (2006); 3 He(γ, n)2p Fetisov et al (1965), Ticcioni et al (1973), Faul et al (1981), Naito et al (2006); 4 He(γ, p) T Shima et al (2001T Shima et al ( ,2005, Kusakabe et al (2009), Arkatov et al (1978b, Gorbunov (1968), Balestra et al (1977); 4 He(γ, n) 3 He Irish et al (1975), Balestra et al (1977), Gorbunov (1968), Shima et al (2001Shima et al ( ,2005, Kusakabe et al (2009), Nilson (2005,2007, Arkatov (1978a); 4 He(γ, D) D Arkatov et al (1980); 4 He(γ, pn) D Shima et al (2001D Shima et al ( ,2005, Arkatov et al (1969b), Gorbunov (1958); 4 He(γ, 2p2n) Balestra et al (1977), Arkatov et al (1969a), Gorbunov (1969). spectral parameters can be obtained by solving the system of ordinary differential equations (4 -7):…”