2024/02/13 by Anne-Katherine Burns, Burns, Anne-Katherine, Venus Keus +5 · 1 citation
Social Sciences · #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #High Energy Physics - Phenomenology (hep-ph) #International Science and Diplomacy #Nuclear Theory (nucl-th)
paper · pdf · doi:10.48550/arxiv.2402.08626
openalex publication_date 2024/02/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
Recently, the EMPRESS collaboration has included new data in the extraction of the primordial 4He abundance from Big Bang Nucleosynthesis (BBN), resulting in a determination that differs from the previous value and from theoretical expectations. There have been several studies attempting to explain this anomaly which involve variation of fundamental constants between the time of BBN and the present. Since the Higgs vacuum expectation value (vev) is the only dimensionful parameter in the Standard Model and it is already known to vary during the electroweak phase transition, we consider the possibility that the vev is slightly different during BBN compared to its present value. A modification of the vev changes not only particle masses but also affects, through mass thresholds, the QCD confinement scale. We use the recently developed PRyMordial program to study this variation and its impact on the 4He and deuterium abundances. We find that bounds on |δv/v| are approximately 0.01, and that the EMPRESS result can be explained within 2σ if 0.008 < δv/v< 0.02, but at the cost of worsening the current 2σ discrepancy in the deuterium abundance to over 3σ.