Observational constraints on cosmic expansion in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si5.svg"> <mml:mrow> <mml:mi>f</mml:mi> <mml:mo>(</mml:mo> <mml:mi>R</mml:mi> <mml:mo>,</mml:mo> <mml:msub> <mml:mi>L</mml:mi> <mml:mi>m</mml:mi> </mml:msub> <mml:mo>,</mml:mo> <mml:mi>T</mml:mi> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> gravity
Annotatsiya
The late-time acceleration of the universe remains one of the central challenges in modern cosmology, motivating both dynamical dark energy models and extensions of general relativity. In this work, we investigate the cosmology of the recently proposed f ( R , L m , T ) gravity framework, which generalizes the f ( R , T ) and f ( R , L m ) models by incorporating the Ricci scalar R , the matter Lagrangian L m , and the trace of the energy-momentum tensor T within a unified gravitational action. By adopting the simplest functional form f ( R , L m , T ) = R + α L m + β T + γ , we derive modified Friedmann equations in a dust-dominated FLRW background and constrain the parameters ( H 0 , α , β , γ ) using cosmic chronometers (CC), Type Ia supernovae from the PantheonPlus (PP)+SH0ES compilation, and their joint dataset. The inferred Hubble constant values are H 0 = 68.69 ± 0.52 km/s/Mpc (CC), 72.75 ± 0.15 km/s/Mpc (PP+SH0ES), and 72 . 68 − 0.12 + 0.15 km/s/Mpc (Joint), while the corresponding deceleration parameters are q 0 ∼ − 0.561 , q 0 ∼ − 0.451 , and q 0 ∼ − 0.458 , respectively. Notably, the obtained H 0 values lie between early-universe and local measurements, indicating that the model can accommodate both low- and high-redshift datasets, partially easing the Hubble tension. The O m ( z ) diagnostic analyses reveal a quintessence-like evolution of the cosmic energy density, distinguishing this framework from the standard Λ CDM model while preserving late-time acceleration.