Negative neutrino masses as a mirage of dark energy

The latest cosmological constraints on the sum of the neutrino masses depend on prior physical assumptions about the mass spectrum. To test the accordance of cosmological and laboratory constraints in the absence of such priors, we introduce an effective neutrino mass parameter that extends consistently to negative values. For the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi mathvariant="normal">Λ</a:mi><a:mi>CDM</a:mi></a:math> model, we analyze data from , the Atacama Cosmology Telescope, and the Dark Energy Spectroscopic Instrument and find a <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mrow><d:mn>2.8</d:mn><d:mi>–</d:mi><d:mn>3.3</d:mn><d:mi>σ</d:mi></d:mrow></d:math> tension with the constraints from oscillation experiments. Motivated by recent hints of evolving dark energy, we analyze the <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:msub><f:mi>w</f:mi><f:mn>0</f:mn></f:msub><f:msub><f:mi>w</f:mi><f:mi>a</f:mi></f:msub></f:math> and mirage dark energy models, finding that they favor larger masses consistent with laboratory data, respectively, <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"><h:mrow><h:mo>∑</h:mo><h:msub><h:mrow><h:mi>m</h:mi></h:mrow><h:mrow><h:mi>ν</h:mi><h:mo>,</h:mo><h:mi>eff</h:mi></h:mrow></h:msub><h:mo>=</h:mo><h:mn>0.0</h:mn><h:msubsup><h:mrow><h:mn>6</h:mn></h:mrow><h:mrow><h:mo>−</h:mo><h:mn>0.10</h:mn></h:mrow><h:mrow><h:mo>+</h:mo><h:mn>0.15</h:mn></h:mrow></h:msubsup><h:mtext> </h:mtext><h:mtext> </h:mtext><h:mi>eV</h:mi></h:mrow></h:math> and <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:mrow><j:mo>∑</j:mo><j:msub><j:mrow><j:mi>m</j:mi></j:mrow><j:mrow><j:mi>ν</j:mi><j:mo>,</j:mo><j:mi>eff</j:mi></j:mrow></j:msub><j:mo>=</j:mo><j:mn>0.0</j:mn><j:msubsup><j:mrow><j:mn>4</j:mn></j:mrow><j:mrow><j:mo>−</j:mo><j:mn>0.11</j:mn></j:mrow><j:mrow><j:mo>+</j:mo><j:mn>0.15</j:mn></j:mrow></j:msubsup><j:mtext> </j:mtext><j:mtext> </j:mtext><j:mi>eV</j:mi></j:mrow></j:math> (both at 68%).