Is there a supernova bound on axions?. (arXiv:1907.05020v1 [hep-ph])
<a href="http://arxiv.org/find/hep-ph/1/au:+Bar_N/0/1/0/all/0/1">Nitsan Bar</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Blum_K/0/1/0/all/0/1">Kfir Blum</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+DAmico_G/0/1/0/all/0/1">Guido D&#x27;Amico</a>

We present a critical assessment of the SN1987A supernova cooling bound on
axions and other light particles. Core-collapse simulations used in the
literature to substantiate the bound omitted from the calculation the envelope
exterior to the proto-neutron star (PNS). As a result, the only source of
neutrinos in these simulations was, by construction, a cooling PNS. We show
that if the canonical delayed neutrino mechanism failed to explode SN1987A, and
if the pre-collapse star was rotating, then an accretion disk would form that
could explain the late-time ($tgtrsim5$ sec) neutrino events. Such accretion
disk would be a natural feature if SN1987A was a collapse-induced thermonuclear
explosion. Axions do not cool the disk and do not affect its neutrino output,
provided the disk is optically-thin to neutrinos, as it naturally is. These
considerations cast doubt on the supernova cooling bound.

We present a critical assessment of the SN1987A supernova cooling bound on
axions and other light particles. Core-collapse simulations used in the
literature to substantiate the bound omitted from the calculation the envelope
exterior to the proto-neutron star (PNS). As a result, the only source of
neutrinos in these simulations was, by construction, a cooling PNS. We show
that if the canonical delayed neutrino mechanism failed to explode SN1987A, and
if the pre-collapse star was rotating, then an accretion disk would form that
could explain the late-time ($tgtrsim5$ sec) neutrino events. Such accretion
disk would be a natural feature if SN1987A was a collapse-induced thermonuclear
explosion. Axions do not cool the disk and do not affect its neutrino output,
provided the disk is optically-thin to neutrinos, as it naturally is. These
considerations cast doubt on the supernova cooling bound.

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