تقرير
Unraveling Trace Anomaly of Supradense Matter via Neutron Star Compactness Scaling
| العنوان: | Unraveling Trace Anomaly of Supradense Matter via Neutron Star Compactness Scaling |
|---|---|
| المؤلفون: | Cai, Bao-Jun, Li, Bao-An |
| سنة النشر: | 2024 |
| المجموعة: | Astrophysics High Energy Physics - Phenomenology High Energy Physics - Theory Nuclear Experiment Nuclear Theory |
| مصطلحات موضوعية: | Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Phenomenology, High Energy Physics - Theory, Nuclear Experiment, Nuclear Theory |
| الوصف: | The trace anomaly $\Delta\equiv 1/3-P/\varepsilon$ quantifies the possibly broken conformal symmetry in supradense matter under pressure $P$ at energy density $\varepsilon$. Perturbative QCD (pQCD) predicts a vanishing $\Delta$ at extremely high energy or baryon densities when the conformal symmetry is realized but its behavior at intermediate densities reachable in neutron stars (NSs) are still very uncertain. The extraction of $\Delta$ from NS observations strongly depends on the employed model for nuclear Equation of State (EOS). Based on the analytical results from perturbatively analyzing the dimensionless Tolman-Oppenheimer-Volkoff (TOV) equations that are further verified numerically by using $10^5$ EOSs generated randomly with a meta-model in a very broad EOS parameter space constrained by terrestrial nuclear experiments and astrophysical observations, here we first show that the compactness $\xi\equiv M_{\rm{NS}}/R$ of a NS with mass $M_{\rm{NS}}$ and radius $R$ scales very accurately with $\Pi_{\rm{c}}\equiv\mathrm{X}/(1+3\mathrm{X}^2+4\mathrm{X})$ where $\mathrm{X}\equiv P_{\rm{c}}/\varepsilon_{\rm{c}}$ is the ratio of pressure over energy density at NS centers. The scaling of NS compactness thus enables one to readily read off the central trace anomaly $\Delta_{\rm{c}}=1/3-\mathrm{X}$ directly from the observational data of either the mass-radius or red-shift measurements. We then demonstrate indeed that the available NS data themselves from recent X-ray and gravitational wave observations can determine model-independently the trace anomaly as a function of energy density in NS cores, providing a stringent test of existing NS models and a clear guidance in a new direction for further understanding the nature and EOS of supradense matter. Comment: 5 pages of main text with 4 pages of supplementary materials |
| نوع الوثيقة: | Working Paper |
| الوصول الحر: | http://arxiv.org/abs/2406.05025Test |
| رقم الانضمام: | edsarx.2406.05025 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |