Cosmological constraints on superweak particles

G. Steigman, K. A. Olive, D. N. Schramm

Research output: Contribution to journalArticlepeer-review

109 Scopus citations


Previous work has used the primordial abundance of He4 to infer limits on the number of neutrinos with full-strength neutral-current weak interactions. By accounting for the quark-gluon constituents of hadrons, we extend the analysis to earlier times and higher temperatures and densities and, therefore, to considerably weaker interactions. The maximum number of new, superweakly interacting, light (a MeV) particles is between ∼1 and ∼20.

Original languageEnglish (US)
Pages (from-to)239-242
Number of pages4
JournalPhysical review letters
Issue number4
StatePublished - 1979
Externally publishedYes


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