New astrophysical constraint on radiatively decaying neutrinos

Journal Article · Mon Jul 01 00:00:00 EDT 1996 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.54.1301· OSTI ID:288205

Sethi, S K ^[1]

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1. Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007 (India)

We calculate constraints on radiatively decaying neutrinos from the recent detection of singly ionized helium in the diffuse intergalactic medium (IGM) at {ital z}{approx_equal}3.3. We consider a model in which neutrinos predominantly decay into invisible relativistic particles with a rate {tau}{sup {minus}1}, and with a small branching ratio into the radiative mode. To satisfy the observation, which puts a lower bound on the number density of singly ionized helium atoms in the IGM, we show that, for {tau}{approx_gt}10{sup 18} sec (1 eV/{ital m}{sub {nu}}{sup 2}), transition moment of neutrinos, {mu}{sub 12}, is constrained to be {le}4{endash}8{times}10{sup {minus}17} {mu}{sub {ital B}} for 110 eV{approx_lt}{ital m}{sub {nu}}{approx_lt}10 keV. Implications of this bound for particle physics and cosmology are briefly discussed. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 288205
• Journal Information: Physical Review, D, Vol. 54, Issue 2; Other Information: PBD: Jul 1996
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
NEUTRINOS
RADIATIVE DECAY
LIMITING VALUES
DETECTION
IONIZATION
HELIUM
BRANCHING RATIO
COSMOLOGY