The electromagnetic fine-structure constant in primordial nucleosynthesis revisited

Abstract

We study the dependence of the primordial nuclear abundances as a function of the electromagnetic fine-structure constant $$\alpha $$ α , keeping all other fundamental constants fixed. We update the leading nuclear reaction rates, in particular the electromagnetic contribution to the neutron-proton mass difference pertinent to $$\beta $$ β -decays, and go beyond certain approximations made in the literature. In particular, we include the temperature-dependence of the leading nuclear reactions rates and assess the systematic uncertainties by using four different publicly available codes for Big Bang nucleosynthesis. Disregarding the unsolved so-called lithium-problem, we find that the current values for the observationally based $${}^{2}\text {H}$$ 2 H and $${}^{4}\text {He}$$ 4 He abundances restrict the fractional change in the fine-structure constant to less than $$2\%$$ 2 % , which is a tighter bound than found in earlier works on the subject.

Search for the Charmed Baryonium and Dibaryon Structures via the QCD Sum Rules

“…The electromagnetic interaction within the deuterium atom contributes to its spectral fine structure, as supported by several studies [1][2][3][4][5]. Similarly, the strong interaction within the singly heavy baryon, constituted by a heavy quark and two light quarks orbiting around the relatively motionless heavy quark, results in the splitting of the hadron spectroscopy.…”