Multidimensionality of the Hubble tension: The roles of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi mathvariant="normal">Ω</mml:mi> <mml:mi>m</mml:mi> </mml:msub> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msub> <mml:mi>ω</mml:mi> <mml:mi>c</mml:mi> </mml:msub> </mml:math>
Davide Pedrotti, Jun-Qian Jiang, Luis A. Escamilla, S. Santos da Costa, Sunny Vagnozzi
Abstract
The Hubble tension is inherently multidimensional and bears important implications for parameters beyond ${H}_{0}$. We discuss the key role of the matter density parameter ${\mathrm{\ensuremath{\Omega}}}_{m}$ and the physical cold dark matter density ${\ensuremath{\omega}}_{c}$. We argue that once ${\mathrm{\ensuremath{\Omega}}}_{m}$ and the physical baryon density ${\ensuremath{\omega}}_{b}$ are calibrated, through baryon acoustic oscillations (BAO) and/or type Ia supernovae (SNeIa) for ${\mathrm{\ensuremath{\Omega}}}_{m}$, and via big bang nucleosynthesis for ${\ensuremath{\omega}}_{b}$, any model raising ${H}_{0}$ requires raising ${\ensuremath{\omega}}_{c}$ and, under minimal assumptions, also the clustering parameter ${S}_{8}$. We explicitly verify that this behavior holds when analyzing recent BAO and SNeIa data. We argue that a calibration of ${\mathrm{\ensuremath{\Omega}}}_{m}$ as reliable and model-independent as possible should be a priority in the Hubble tension discussion, and an interesting possibility in this sense could be represented by galaxy cluster gas mass fraction measurements.