Revision 1

Accepted · first revision · record

Title: Is the weak scale set by cosmological dynamics or selection?
Plain: Instead of new particles at the TeV scale, the Higgs mass might have been adjusted during the early universe by a slowly evolving field, or selected among many possible universes. Such ideas predict light, weakly coupled particles instead of heavy ones.
Precise: Assess mechanisms in which v is fixed dynamically by cosmological evolution (relaxion scanning of $m_h^{2}$, NNaturalness, crunching of regions with large v) rather than by TeV-scale symmetry. An answer is a consistent model that reproduces $v = 246\,\mathrm{GeV}$ without large tuning and an experimental signature (for example relaxion-Higgs mixing or fifth forces) that can confirm or exclude it.
Settled by: Detection or exclusion of the light scalar predicted by relaxation models through Higgs-mixing searches, fifth-force tests and rare-decay searches across its allowed mass range.
Kind: phenomenon
Answer type: mechanism
References: (empty)
Literature status: open
Status note: Relaxion proposals date from 2015; consistent models exist but require long inflation or other non-minimal features, and none has a confirmed signature.
Posed since: 2015