SN-nuclei R. X. Xu Renxin Xu ( 徐仁新 ) 1,2 1 School of Physics, Peking University ( ) 2 Kavli Institute for Astronomy and Astrophysics SINAP-CUSTIPEN Workshop on Clusters and Correlations in Nuclei, Nuclear Reactions and Neutron Stars December 14-18, 2015; Shanghai, China Supernova-produced Exotic Nuclei

Pulsar-like star is the rump left behind after supernova Normal baryonic matter is intensely compressed by gravity here! CBM Pulsar = Big exotic nucleus with 3-flavor symmetry? I could like to start with a question to explain my idea…

Why our baryonic matter is 2-flavor- (rather than 1- or 3-) symmetric? Note: Energy scale ~ 0.4 GeV < 1 GeV (~0.5 fm) pc ~  c ~ 200 MeV·fm Anthropic principle? S trange M atter NQCD!

Summary Strange Matter: bigger is diff.! Observational hints from SM? Conclusions SN-nuclei R. X. Xu

The symmetry-energy in liquid-drop model Five terms in mass formula of nucleus with Z protons and N neutrons (A = Z + N): E (Z, N) = volumesurfacesymmetryCoulombpairing Why does there exist symmetry-energy? Fermi gas of nucleons: still weakly interaction inside a nucleus? E pn EFEF  For non-relativistic neutrons and protons: p F  n 1/3, E F  n 2/3   Interaction really negligible? The kinetic term of Nuclear Symmetry Energy Strange Matter: bigger is diff.!

Fermi gas of nucleons: still weakly interaction inside a nucleus? Alternatively, stronger interaction there? (an analogy: NaCl) A note: electrons have to participate in 2-flavour symmetry matter! …but it doesn't matter for microscopic nuclei because of  em <<  s.. l ~ A ~ 10 4 fm kinematic motion is bound by EM interaction: p 2 /m e ~ e 2 /l Heisenberg’s relation: p  l ~    Electrons contribute negligible energy for micro-nuclei! 。 ~ MeV The potential term of Nuclear Symmetry Energy dominates! Strange Matter: bigger is diff.! 2-flavuor micro-nuclei is energetically favored! SN-nuclei R. X. Xu

3-flvuor symmetry in gigantic/macro-nuclei? Huge Thomson atom if 2-flavour symmetry keeps... Huge Thomson atom with A > 10 9 disadvantages: though Coulomb energy could not be significant, but the Fermi energy of electrons: E F ~  cn 1/3 ~ 10 2 MeV! advantages if strangenization... (1) minimizing the electron’s contribution of kinetic energy, (2) maximizing the flavour number (only 2 if neutronization!). Micro-nucleus: 2 -f nucleon VS. Macro-nucleus: 3 -f quark-cluster Strange Matter: bigger is diff.! >> c ~ 10 3 fm SN-nuclei R. X. Xu

2-f micro-nucleus VS 3-f macro-nucleus proton neutron f = 2f = 3 u u d u d d u s d d u s Strange Matter: condensed matter of quark-clusters! Strange Matter: bigger is diff.! ~ fm > c ~ 10 3 fm Quantum gas/liquid?Classical solid?! (an extension of the Bodmer–Witten conjecture: strange quark matter) SN-nuclei R. X. Xu

Summary Strange Matter: bigger is diff.! Observational hints from SM? Conclusions SN-nuclei R. X. Xu

CBM is produced inside massive stars after SN SN occurs due to gravitational energy release when nuclear power cannot stand against gravity. Where and observational evidence? Pulsar: neutron/strange? SN-nuclei R. X. Xu

Pulsars: Neutron star V.S. Strange star Observational hints from SM? What if normal baryonic matter is compressed by gravity in a core of massive evolved star, the nature of compressed baryonic matter (CBM)? It is very necessary to kill the electrons by weak interaction… SN-nuclei R. X. Xu

Pulsars: different models in the market… conventional Neutron Star light flavour symmetry: Strange Star Observational hints from SM? SN-nuclei R. X. Xu

1 Quark-cluster stars Normal neutron stars Xu (2008) Pulsars: Observational hints? Observational hints from SM?

Subpulse drifting: PSG or self-bound surface? Bi-drifting: strong self-bound quark surface? Nonatomic spectra: quark surface? Clean fireball for SNE & GRB? Precessions of pulsars? Quake-induced free energy for AXP/SGRs? Non-thermal emission: bound strongly? Thermal emission: featureless & clear? Quark-cluster stars in a solid state? Obs. tests of stiff equation of state? Surface Global Observational hints from SM? SN-nuclei R. X. Xu

Observational hints from SM? SN-nuclei R. X. Xu

Watts et al. (2015) Hyperon puzzle? Quark-confinement? in this quark-cluster star model Observational hints from SM?

Photospheric radius expansion in 4U Constraints by PRE bursts of 4U , on the assumption that the touchdown flux corresponded to L Edd, and the obscure effect is included. Li, et al. (ApJ, 2015) Compact stars: low-mass pulsar-like star? Observational hints from SM? SN-nuclei R. X. Xu

Nucita et al. (2014) H-like Ly-α Lines at E/eV : {10.2, 40.8, 91.8, 163.2, 255, 367.2, 500,., 826.2, 1020, , , , , 2295, , , , , 4080,...} The puzzling symbiotic X-ray system 4U

1.Red-shift: z ~ 0.009! 2.X-ray black body radiation area (A 1/2 ~ m) reduce as L x decreases. 3.The mass function via by observing the G-type red giant company is only f o ~ M ⊙ ! ⇒ All 3 could be understood if M compact is only ~ M ⊙ unless geometrically fine-turn. Observational hints from SM? SN-nuclei R. X. Xu

To find clear observational evidence by  PSR mass measurements (M)  PSR moment of inertia measurements (I)  Discovering fastest spinning PSRs (P)  Magnetospheric activity (pulse-profile) Observational hints from SM? future… SN-nuclei R. X. Xu

Example of future facility ： ground-based FAST SKA

Pulsar science is elected as one of key projects  Xiangshan meeting S21: Chinese SKA“2+1”strategy “2”= HI & PSR “1”= others SKA“SRP” Example of future facility ： ground-based

+ = HXMT  XTP eXTP ： 1 奇 2 星 3 极端 Example of future facility ： space-based

Summary Strange Matter: bigger is diff.! Observational hints from SM? Conclusions SN-nuclei R. X. Xu

Conclusions Although normal micro-nuclei are 2-flavour symmetric, we argue that 3-flavour symmetry would be restored in macro/gigantic-nuclei compressed by gravity during a supernova. Strange matter is conjectured to be condensed matter of 3-flavour quark-clusters, and future advanced facilities (FAST/SKA, HXMT/eXTP) would provide clear evidence for strange stars. THANKS! SN-nuclei R. X. Xu