Year: 2026
Type: article
Abstract: In this work, we examine Big Bang nucleosynthesis (BBN) within the framework of f ( Q, C ) gravity by considering three representative functional forms of the gravitational Lagrangian. The first model is constructed from quadratic contributions involving the nonmetricity scalar Q and the boundary term C . The second employs a separable form containing the standard linear dependence on Q together with a logarithmic correction associated with C , whereas the third model introduces a multiplicative coupling between Q and C . For each scenario, we investigate the background dynamics during the radiation-dominated phase and assess whether the resulting expansion history is compatible with the requirements of successful BBN. We subsequently derive constraints on the corresponding model parameters by confronting the predicted primordial abundances of the principal light elements, with particular emphasis on helium-4 and deuterium. Among the three cases considered, the second model yields the most favorable agreement with the observationally inferred primordial abundances of helium-4 and deuterium, thereby identifying a viable region of its parameter space.
Source: Physics Letters B
Authors: Subhajit Sarkar, Ujjal Debnath
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7219019447