Enhanced muonization by active-sterile neutrino mixing in protoneutron stars

We study <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>ν</a:mi></a:mrow><a:mrow><a:mi>μ</a:mi></a:mrow></a:msub><a:mtext>−</a:mtext><a:msub><a:mrow><a:mi>ν</a:mi></a:mrow><a:mrow><a:mi>s</a:mi></a:mrow></a:msub></a:mrow></a:math> and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:msub><c:mrow><c:mover accent="true"><c:mrow><c:mi>ν</c:mi></c:mrow><c:mrow><c:mo stretchy="false">¯</c:mo></c:mrow></c:mover></c:mrow><c:mrow><c:mi>μ</c:mi></c:mrow></c:msub><c:mtext>−</c:mtext><c:msub><c:mrow><c:mover accent="true"><c:mrow><c:mi>ν</c:mi></c:mrow><c:mrow><c:mo stretchy="false">¯</c:mo></c:mrow></c:mover></c:mrow><c:mrow><c:mi>s</c:mi></c:mrow></c:msub></c:mrow></c:math> mixing in the protoneutron star (PNS) created in a core-collapse supernova (CCSN). We point out the importance of the feedback on the general composition of the PNS in addition to the obvious feedback on the <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:msub><i:mi>ν</i:mi><i:mi>μ</i:mi></i:msub></i:math> lepton number. We show that for our adopted mixing parameters <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mrow><k:mi>δ</k:mi><k:msup><k:mrow><k:mi>m</k:mi></k:mrow><k:mrow><k:mn>2</k:mn></k:mrow></k:msup><k:mo>∼</k:mo><k:msup><k:mrow><k:mn>10</k:mn></k:mrow><k:mrow><k:mn>2</k:mn></k:mrow></k:msup><k:mtext> </k:mtext><k:mtext> </k:mtext><k:msup><k:mrow><k:mi>keV</k:mi></k:mrow><k:mrow><k:mn>2</k:mn></k:mrow></k:msup></k:mrow></k:math> and <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"><m:msup><m:mi>sin</m:mi><m:mn>2</m:mn></m:msup><m:mn>2</m:mn><m:mi>θ</m:mi></m:math> consistent with the current constraints, sterile neutrino production is dominated by the Mikheyev–Smirnov–Wolfenstein conversion of <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"><o:msub><o:mover accent="true"><o:mi>ν</o:mi><o:mo stretchy="false">¯</o:mo></o:mover><o:mi>μ</o:mi></o:msub></o:math> into <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"><s:msub><s:mover accent="true"><s:mi>ν</s:mi><s:mo stretchy="false">¯</s:mo></s:mover><s:mi>s</s:mi></s:msub></s:math> and that the subsequent escape of <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" display="inline"><w:msub><w:mover accent="true"><w:mi>ν</w:mi><w:mo stretchy="false">¯</w:mo></w:mover><w:mi>s</w:mi></w:msub></w:math> increases the <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"><ab:msub><ab:mi>ν</ab:mi><ab:mi>μ</ab:mi></ab:msub></ab:math> lepton number, which in turn enhances muonization of the PNS primarily through <cb:math xmlns:cb="http://www.w3.org/1998/Math/MathML" display="inline"><cb:msub><cb:mi>ν</cb:mi><cb:mi>μ</cb:mi></cb:msub><cb:mo>+</cb:mo><cb:mi>n</cb:mi><cb:mo stretchy="false">→</cb:mo><cb:mi>p</cb:mi><cb:mo>+</cb:mo><cb:msup><cb:mi>μ</cb:mi><cb:mo>−</cb:mo></cb:msup></cb:math>. While these results are qualitatively robust, their quantitative effects on the dynamics and active neutrino emission of core-collapse supernovae should be evaluated by including <fb:math xmlns:fb="http://www.w3.org/1998/Math/MathML" display="inline"><fb:mrow><fb:msub><fb:mrow><fb:mi>ν</fb:mi></fb:mrow><fb:mrow><fb:mi>μ</fb:mi></fb:mrow></fb:msub><fb:mtext>−</fb:mtext><fb:msub><fb:mrow><fb:mi>ν</fb:mi></fb:mrow><fb:mrow><fb:mi>s</fb:mi></fb:mrow></fb:msub></fb:mrow></fb:math> and <hb:math xmlns:hb="http://www.w3.org/1998/Math/MathML" display="inline"><hb:mrow><hb:msub><hb:mrow><hb:mover accent="true"><hb:mrow><hb:mi>ν</hb:mi></hb:mrow><hb:mrow><hb:mo stretchy="false">¯</hb:mo></hb:mrow></hb:mover></hb:mrow><hb:mrow><hb:mi>μ</hb:mi></hb:mrow></hb:msub><hb:mtext>−</hb:mtext><hb:msub><hb:mrow><hb:mover accent="true"><hb:mrow><hb:mi>ν</hb:mi></hb:mrow><hb:mrow><hb:mo stretchy="false">¯</hb:mo></hb:mrow></hb:mover></hb:mrow><hb:mrow><hb:mi>s</hb:mi></hb:mrow></hb:msub></hb:mrow></hb:math> mixing in the simulations. Published by the American Physical Society 2024