BBN constraints on f(Q,T) gravity

f(Q,T) gravity is a novel extension of the symmetric teleparallel gravity where the Lagrangian L is represented through an arbitrary function of the nonmetricity Q and the trace of the energy-momentum tensor T.23 In this work, we have constrained a widely used f(Q,T) gravity model of the form f(Q,T) = Qa+1 + bT from the primordial abundances of the light elements to understand its viability in cosmology. We report that the f(Q,T) gravity model can elegantly explain the observed abundances of Helium and Deuterium while the Lithium problem persists. From the constraint on the expansion factor in the range 0.9425 ≤Z ≤1.1525, we report strict constraints on the parameters a and b in the range 0.01 ≤a-0.01 and-5.86 ≤b ≤12.52, respectively. © 2022 World Scientific Publishing Company