<p>Dark matter admixed neutron stars (DANSs) provide a unique laboratory for probing fundamental dark matter (DM) properties and offer explanations for recent NICER and LIGO/Virgo observations. Accurately constraining their internal DM content is essential. In this work, we construct equations of state for DANS matter by combining twelve covariant density functional nuclear models with a self-interacting bosonic DM model. Solving the two-fluid Tolman-Oppenheimer-Volkoff equations, we systematically examine DM effects on neutron star properties and employ the latest observational constraints to determine the maximum DM mass fraction <InlineEquation ID="IEq1"> <EquationSource Format="MATHML"><math> <msubsup> <mi>f</mi> <mi>χ</mi> <mi mathvariant="normal">max</mi> </msubsup> </math></EquationSource> <EquationSource Format="TEX">$f_{\chi }^{\mathrm{max}}$</EquationSource> </InlineEquation> for each nuclear model. Our analysis reveals a robust linear correlation between <InlineEquation ID="IEq2"> <EquationSource Format="MATHML"><math> <msubsup> <mi>f</mi> <mi>χ</mi> <mi mathvariant="normal">max</mi> </msubsup> </math></EquationSource> <EquationSource Format="TEX">$f_{\chi }^{\mathrm{max}}$</EquationSource> </InlineEquation> and the maximum mass of pure neutron stars <InlineEquation ID="IEq3"> <EquationSource Format="MATHML"><math> <msubsup> <mi>M</mi> <mi mathvariant="normal">NS</mi> <mi mathvariant="normal">max</mi> </msubsup> </math></EquationSource> <EquationSource Format="TEX">$M_{\mathrm{NS}}^{\mathrm{max}}$</EquationSource> </InlineEquation>. Using this correlation together with the constrained distribution <InlineEquation ID="IEq4"> <EquationSource Format="MATHML"><math> <mi>P</mi> <mo stretchy="false">(</mo> <msubsup> <mi>M</mi> <mtext>NS</mtext> <mo movablelimits="false">max</mo> </msubsup> <mo stretchy="false">∣</mo> <mtext>EM</mtext> <mo stretchy="false">)</mo> </math></EquationSource> <EquationSource Format="TEX">$P(M_{\text{NS}}^{\max } \mid \text{EM})$</EquationSource> </InlineEquation>, we derive the probability distribution function for the maximum DM mass in DANSs, <InlineEquation ID="IEq5"> <EquationSource Format="MATHML"><math> <mi>P</mi> <mo stretchy="false">(</mo> <msubsup> <mi>M</mi> <mi>χ</mi> <mo movablelimits="false">max</mo> </msubsup> <mo stretchy="false">∣</mo> <mtext>EM</mtext> <mo stretchy="false">)</mo> </math></EquationSource> <EquationSource Format="TEX">$P(M_{\chi }^{\max } \mid \text{EM})$</EquationSource> </InlineEquation>. At the 68% confidence level, we obtain <InlineEquation ID="IEq6"> <EquationSource Format="MATHML"><math> <msubsup> <mi>M</mi> <mi>χ</mi> <mi mathvariant="normal">max</mi> </msubsup> <mo>=</mo> <msubsup> <mn>0.157</mn> <mrow> <mo>−</mo> <mn>0.040</mn> </mrow> <mrow> <mo>+</mo> <mn>0.059</mn> </mrow> </msubsup> <mspace width="0.25em" /> <mi>M</mi> <mo>⊙</mo> </math></EquationSource> <EquationSource Format="TEX">$M_{\chi }^{\mathrm{max}}=0.157^{+0.059}_{-0.040}\ M{\odot }$</EquationSource> </InlineEquation>. This quantitative constraint provides a critical prior for interpreting potential DANS signatures, including anomalous tidal deformabilities and distinctive gravitational-wave signals.</p>

Constraints on dark matter in neutron stars from recent observations and mass correlation analysis

期刊论文
发表日期：

2026年5月21日

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Jing Fu Hu,
Hang Lu

摘要

Dark matter admixed neutron stars (DANSs) provide a unique laboratory for probing fundamental dark matter (DM) properties and offer explanations for recent NICER and LIGO/Virgo observations. Accurately constraining their internal DM content is essential. In this work, we construct equations of state for DANS matter by combining twelve covariant density functional nuclear models with a self-interacting bosonic DM model. Solving the two-fluid Tolman-Oppenheimer-Volkoff equations, we systematically examine DM effects on neutron star properties and employ the latest observational constraints to determine the maximum DM mass fraction $f_{χ}^{\max}$ $f_{\chi }^{\mathrm{max}}$ for each nuclear model. Our analysis reveals a robust linear correlation between $f_{χ}^{\max}$ $f_{\chi }^{\mathrm{max}}$ and the maximum mass of pure neutron stars $M_{NS}^{\max}$ $M_{\mathrm{NS}}^{\mathrm{max}}$ . Using this correlation together with the constrained distribution $P (M_{NS}^{max} ∣ EM)$ $P(M_{\text{NS}}^{\max } \mid \text{EM})$ , we derive the probability distribution function for the maximum DM mass in DANSs, $P (M_{χ}^{max} ∣ EM)$ $P(M_{\chi }^{\max } \mid \text{EM})$ . At the 68% confidence level, we obtain $M_{χ}^{\max} = {0.157}_{- 0.040}^{+ 0.059} M ⊙$ $M_{\chi }^{\mathrm{max}}=0.157^{+0.059}_{-0.040}\ M{\odot }$ . This quantitative constraint provides a critical prior for interpreting potential DANS signatures, including anomalous tidal deformabilities and distinctive gravitational-wave signals.