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arXiv · 2209.01595

Big Bang Nucleosynthesis constraints on $f(T,T_G)$ gravity

Petros Asimakis·Emmanuel N. Saridakis·Spyros Basilakos·Kuralay Yesmakhanova
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Abstract

We confront $f(T,T_G)$ gravity, with Big Bang Nucleosynthesis (BBN) requirements. The former is obtained using both the torsion scalar, as well as the teleparallel equivalent of the Gauss-Bonnet term, in the Lagrangian, resulting to modified Friedmann equations in which the extra torsional terms constitute an effective dark energy sector. We calculate the deviations of the freeze-out temperature $T_f$, caused by the extra torsion terms in comparison to $\Lambda$CDM paradigm. Then we impose five specific $f(T,T_G)$ models and we extract the constraints on the model parameters in order for the ratio $|\Delta T_f/ T_f|$ to satisfy the observational BBN bound. As we find, in most of the models the involved parameters are bounded in a narrow window around their General Relativity values as expected, as in the power-law model where the exponent $n$ needs to be $n\lesssim 0.5$. Nevertheless the logarithmic model can easily satisfy the BBN constraints for large regions of the model parameters. This feature should be taken into account in future model building.

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Petros Asimakis, Emmanuel N. Saridakis, Spyros Basilakos, Kuralay Yesmakhanova. 2022-09-04. Big Bang Nucleosynthesis constraints on $f(T,T_G)$ gravity. https://doi.org/10.3390/universe8090486

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