A heavy neutrino may explain how matter survived the Big Bang
Researchers from the University of Southampton and the Indian Institute of Technology Kanpur propose that a hypothetical decoupled heavy neutrino briefly dominated the early universe’s energy density. Their calculations suggest it may have shifted when particles interacted with their antiparticles, helping produce the matter surplus; the theory remains unproven.
Bottom line — The researchers say primordial gravitational-wave signatures could offer a way to test the heavy-neutrino theory.
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The study was published in Physical Review Letters.
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Southampton researcher Rishav Roshan said the particle’s unusually slow decay let it persist as the cosmos cooled.
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The researchers say the particle may have changed the temperature at which interactions involving electrons and other leptons helped build the matter–antimatter imbalance.
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Co-author Sudipta Show of the Indian Institute of Technology Kanpur said the particle may also have altered the early universe’s expansion.