Is Dynamical Dark Energy Necessary? DESI BAO and Modified Recombination

Fuente: arXiv
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Autori principali: Mirpoorian, Seyed Hamidreza, Jedamzik, Karsten, Pogosian, Levon
Natura: Preprint
Pubblicazione: 2025
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author Mirpoorian, Seyed Hamidreza
Jedamzik, Karsten
Pogosian, Levon
author_facet Mirpoorian, Seyed Hamidreza
Jedamzik, Karsten
Pogosian, Levon
contents Recent measurements of baryon acoustic oscillations (BAO) by the Dark Energy Spectroscopic Instrument (DESI) exhibit a mild-to-moderate tension with cosmic microwave background (CMB) and Type Ia supernova (SN) observations when interpreted within the $Λ$CDM framework. This discrepancy has been cited as evidence for dynamical dark energy (DDE). Given the profound implications of DDE for fundamental physics, we explore whether the tension can instead be resolved by modifying the physics of recombination. We find that a phenomenological model of modified recombination can effectively reconcile the BAO and CMB datasets and, unlike DDE, also predicts a higher Hubble constant $H_0$, thereby partially alleviating the Hubble tension. A global fit to BAO, CMB, and calibrated SN data favors modified recombination over DDE.
format Preprint
id arxiv_https___arxiv_org_abs_2504_15274
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Is Dynamical Dark Energy Necessary? DESI BAO and Modified Recombination
Mirpoorian, Seyed Hamidreza
Jedamzik, Karsten
Pogosian, Levon
Cosmology and Nongalactic Astrophysics
Recent measurements of baryon acoustic oscillations (BAO) by the Dark Energy Spectroscopic Instrument (DESI) exhibit a mild-to-moderate tension with cosmic microwave background (CMB) and Type Ia supernova (SN) observations when interpreted within the $Λ$CDM framework. This discrepancy has been cited as evidence for dynamical dark energy (DDE). Given the profound implications of DDE for fundamental physics, we explore whether the tension can instead be resolved by modifying the physics of recombination. We find that a phenomenological model of modified recombination can effectively reconcile the BAO and CMB datasets and, unlike DDE, also predicts a higher Hubble constant $H_0$, thereby partially alleviating the Hubble tension. A global fit to BAO, CMB, and calibrated SN data favors modified recombination over DDE.
title Is Dynamical Dark Energy Necessary? DESI BAO and Modified Recombination
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2504.15274