Nuclear Astrophysics at SJTU Lie-Wen Chen ( ) Department of Physics - - PowerPoint PPT Presentation

Nuclear Astrophysics at SJTU

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Center for Nuclear Astrophysics (CNA)/SJTU

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Neutrinos in Astrophysics

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Nucleosynthesis

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Neutron Stars

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Laboratory Astrophysics

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Conclusion Lie-Wen Chen (陈列文)

Department of Physics and Astronomy, Shanghai Jiao Tong University, China (lwchen@sjtu.edu.cn)

2015 SJTU-KIT Collaborative Research Workshop “Particles and the Universe”, November 4-6, 2015, SJTU, Shanghai, China

Contents

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Center for Nuclear Astrophysics (CNA)/SJTU

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Neutrinos in Astrophysics

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Nucleosynthesis

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Neutron Stars

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Laboratory Astrophysics

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Conclusion

CNA/INPAC Founded

CNA/INPAC (Center for Nuclear Astropysics/Institute of Nuclear and PArtiCle Physics) was founded on May 29, 2013

 Neutrinos in Astrophysics  Nucleosynthesis  Neutron stars  Laboratory Astrophysics  ……

http://cna.physics.sjtu.edu.cn/

• p. 1

CNA/INPAC Founded

Associated institution of JINA-CEE (The Joint Institute for Nuclear Astrophysics - Center for the Evolution of the Elements) Promote nuclear astrophysics development in China Promote international collaborations and academic exchanges in this field Carry out conversations from different fields in China

• Nuclear experimental facilities in IMP (Lanzhou), CIAE (Beijing)
• JinPing underground lab (Sichuan)
• JiangMen neutrino lab (Guangdong)
• Shanghai synchrotron light (upgrade to provide gamma rays)
• Strong laser facilities (ShenGuang)
• Large telescope LAMOST (Beijing)
• Supercomputer Tian-He (Tianjin)
• p. 2

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Center for Nuclear Astrophysics (CNA)/SJTU

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Neutrinos in Astrophysics

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Nucleosynthesis

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Neutron Stars

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Laboratory Astrophysics

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Conclusion

Contents

Neutrino in Wikipedia

Neutrino was postulated first by Wolfgang Pauli in 1930 to explain how beta decay could conserve energy, momentum, and angular momentum (spin). Neutrinos can interact with a nucleus, changing it to another nucleus. In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a proton is transformed into a neutron, or vice versa, inside an atomic nucleus. This process allows the atom to move closer to the optimal ratio of protons and neutrons.

• p. 3

Neutrino in Astrophysics

 Weak interaction (neutrino) plays an extremely important role for the synthesis of elements in various astrophysical conditions

Neutron star

Supernovae Neutron Star Merger X-Ray Burst Gamma-Ray Burst

• p. 4

Neutrino Astrophysics

 Ultra high energy (Peta-eV) neutrinos have been observed at IceCube  The flavors e and mu are dominant Gang Guo and Yong-Zhong Qian, 2015

Potential Signatures of High-Energy Neutrinos Produced by Relativistic Jets in Gamma-Ray Bursts and Core-Collapse Supernovae

• p. 5

Neutrino Astrophysics

 HE neutrinos from shocks may annihilate the thermal neutrinos from accretion disk, and thus modify the spectra and flavor of HE neutrinos Gang Guo and Yong-Zhong Qian, 2015

Potential Signatures of High-Energy Neutrinos Produced by Relativistic Jets in Gamma-Ray Bursts and Core-Collapse Supernovae

Core-Collapse Supernovae: BH + GRB GRB

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Center for Nuclear Astrophysics (CNA)/SJTU

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Neutrinos in Astrophysics

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Nucleosynthesis

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Neutron Stars

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Laboratory Astrophysics

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Conclusion

Contents

Element abundance in the solar system

• p. 7

Nucleosynthesis

 Fe fraction is smaller for older stars Zhen Yuan, Yong-Zhong Qian, and Yi-Peng Jing, 2015

Formation and evolution of elements in the Universe Gas Dynamics and Chemical Evolution of the Fornax Dwarf Spheroidal Galaxy

• p. 8

Nucleosynthesis

 The fraction of Magnesium, Calcium, and Silicon can be reasonably reproduced by the model (but not for Titanium) Zhen Yuan, Yong-Zhong Qian, and Yi-Peng Jing, 2015

Formation and evolution of elements in the Universe Gas Dynamics and Chemical Evolution of the Fornax Dwarf Spheroidal Galaxy

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Synthesis of Heavy Elements

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e



Synthesis of elements heavier than Fe — n-capture (Z, A) + n → (Z, A+1) +γ β-decay：(Z, A+1) → (Z+1, A+1) + e- +

1) Slow process (s-process)

n-capture is slower than β-decay

Inside the stars， Synthesis → 209Bi(铋,Z=83)。 2) Rapid process (r-process) n-capture is faster than β-decay Supernovae， Synthesis→ 251Cf(锎,Z=98)。

 The astrophysical rapid neutron capture process (r-process) which occurs along a path very close to the neutron dripline in the nuclear landscape via neutron-rich nuclei with experimentally unknown mass and half-lives and provides a nucleosynthesis mechanism for the origin of more than half of the heavy nuclei in the Universe

Synthesis of Heavy Elements

• p. 11

Importance of nuclear structure in element synthesis

Nuclear structure controls the clock for the stellar processes

• the total time along the reaction path entirely determines the

speed of nucleosynthesis towards heavier nuclei and the produced isotopic abundances

We need to know:

• nuclear masses (ground state properties, energy gaps,

single-particle levels, ...)

• nuclear structure (nuclear deformation, collective excitations,

quasiparticle excitations, isomeric states, …)

• capture rates
• b-decay rates

Yang Sun (Projected Shell Model), Yu-Min Zhao (Pairing Shell Model, Mass Formula), Lie-Wen Chen (Density Functional Theory)

• p. 12

Neutron Dripline and r-process paths

 The symmetry energy at subsaturation densities controls the position of neutron dripline and the r-process paths (within DFT)  Up to Z=120, the number of even-even nuclei is 1941+/-31 (only 800 have been discovered experimentally) and the total number of bound nuclei is 6866+/-166 (only 3191 have been discovered experimentally) Exp: M. Thoennessen, Rep. Prog. Phys. 76, 056301(2013); Int. J. Mod. Phys. E 23, 1430002 (2014); arXiv:1501.06761.

• R. Wang and L.W. Chen, PRC92, 031303 (R) (2015) (arXiv:1410.2498)
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Center for Nuclear Astrophysics (CNA)/SJTU

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Neutrinos in Astrophysics

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Nucleosynthesis

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Neutron Stars

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Laboratory Astrophysics

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Conclusion

Contents

Neutron Stars

E&M Weak Gravity Strong

Stable Neutron Stars @beta equilibrium and charge neutrality Determined by the 4 forces together Interior of NStar: Very dense matter

• F. Weber, PPNP54, 193 (2005)

30 5 6

• 10

Earth: mass 3 10 M , radius=6378km, compactness Neutron stars: Sun: M 2 10 kg, mass 1.4 M , radius 10km, compactness M/R 0.14 M/R 5 10 (M /km) R 7 (M /km) 10 km



     

e e e e e e

; ; : : :

• p. 14

Key Quantity: EOS of neutron star matters

Neutron stars consist of β-equilibrium npeμ matter with charge neutrality

Structure of Neutron Stars

Tolman-Oppenheimer-Volkov (TOV) Equation

(R.C. Tolman, Phys. Rev. 55, 364 (1939); J.R. Oppenheimer and G.M. Volkoff, Phys.

• Rev. 55, 374 (1939).)

where r is the radial coordinate, M(r) is the gravitational mass inside the sphere of radius r, e(r) and P(r) are, respectively, the corresponding energy density and pressure of the neutron star matter (EOS) at r, and G is Newton’s gravitational constant.

• p. 15

EOS of Isospin Asymmetric Nuclear Matter

s 2 4 ym( )

( , ) ( ), ( ) ,0) / (

n p

E O E E               

(Parabolic law)

Nuclear Matter Symmetry Energy

2 sym 2

1 ( , ) ( ) 2 E E       

The Symmetry Energy

Symmetry energy term (poorly known) Symmetric Nuclear Matter (relatively well-determined) Isospin asymmetry

sym sym sym 2 sym sym

, ( ) 3 18 30 MeV (LD mass formula: ) ( ) 3 (Many- 50 ~ B 2 (

• dy

0 Me Theo ( ) ry: : ; Ex ) ~ V p ( ) E My E ers & Swiatecki, NPA81; Pomorski & D K L E udek, P E R 7 L C6 L

 

             



                       

sy 2 sym 2 sym 2 m

: ???) ( ) 9 (Many-Body Theory: : ; Exp: ? 700 ~ 4 ?? V ) 66 Me K E K

 

  



   

• p. 16

Promising Probes of the Esym(ρ) (an incomplete list !)

Esym: Experimental Probes

At sub-saturation densities (亚饱和密度行为)

 Sizes of n-skins of unstable nuclei from total reaction cross sections  Proton-nucleus elastic scattering in inverse kinematics  Parity violating electron scattering studies of the n-skin in 208Pb  n/p ratio of FAST, pre-equilibrium nucleons  Isospin fractionation and isoscaling in nuclear multifragmentation  Isospin diffusion/transport  Neutron-proton differential flow  Neutron-proton correlation functions at low relative momenta  t/3He ratio  Hard photon production

Towards high densities reachable at CSR/Lanzhou, FAIR/GSI, RIKEN, GANIL and, FRIB/MSU (高密度行为)

 π -/π + ratio, K+/K0 ratio?  Neutron-proton differential transverse flow  n/p ratio at mid-rapidity  Nucleon elliptical flow at high transverse momenta  n/p ratio of squeeze-out emission

 Pigmy/Giant resonances  Nucleon optical potential

B.A. Li, L.W. Chen, C.M. Ko

• Phys. Rep. 464, 113(2008)
• p. 17

QCD Phase Diagram in 3D: density, temperature, and isospin

At extremely high baryon density, the main degree of freedom could be the deconfined quark matter rather than confined baryon matter, and there we should consider quark matter symmetry energy (isospin symmetry is still satisfied). The isopsin asymmetric quark matter could be produced/exist in HIC/Compact Stars

V.E. Fortov, Extreme States of Matter – on Earth and in the Cosmos, Springer-Verlag Berlin Heidelberg 2011

Phase Diagram of Strong Interaction Matter

Quark Matter Symmetry Energy ?

• M. Di Toro et al. NPA775, 102(2006);

Pagliara/Schaffner-Bielich, PRD81, 094024(2010); Shao et al., PRD85, 114017(2012);Chu/Chen, ApJ780, 135 (2014)

Esym: Important for understanding the EOS of strong interaction matter and QCD phase transitions at extreme isospin conditions

• 1. Heavy Ion Collisions

(Terrestrial Lab);

• 2. Compact Stars(In Heaven); …
• p. 18

Symmetry Energy and Dark Matter

Zheng/Zhang/Chen, JCAP08(2014)011

Isospin-Violating DM - n/p form factor

• neutron skin - Esym

Zheng/Sun/Chen, ApJ800, 141 (2015)

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Total mass

• r

So small !

t: the living age of the neutron star For old neutron stars around the earth: f: contains all the effects caused by different neutron star structures

DM Capture by Neutron Stars

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Black hole formation Black Hole Formation

Captured DM will go on scattering with star matters and accumulate within a small radius at the star core When the mass of the DM exceed the Chandrasekhar limit (for non-interacting ADM) Planck mass: Black hole forms and it will eventually destroy the whole neutron star

too large

So we require to ensure the existence of the old neutron stars

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Neutron stars as DM probe

Zheng/Sun/Chen, ApJ800, 141 (2015) The pulsar PSR B1257+12 is a planetary system with one solitary neutron star being orbited by three planets located 0.6 kpc away from the solar system. Its age is about 0.862 Gyr (Ts=10^5 K and M=1.4Msun) For low mass Bosonic DM (<20 GeV), the constraint from NS is much stronger than that from direct detection experiments !

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Center for Nuclear Astrophysics (CNA)/SJTU

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Neutrinos in Astrophysics

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Nucleosynthesis

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Neutron Stars

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Laboratory Astrophysics

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Conclusion

Contents

Laser Plasma Collider

Stream 1 Stream 2

Overlap

Region 4.4 mm

(a)

 Neutrons with a characteristic energy of 2.45 MeV had been produced from D-D collisions  Opened a door for future nuclear reaction experiments under astrophysical conditions.

Chang-Bo Fu et al. , Science Bulletin. 60, 1211 (2015). (See Poster of Xiao-Peng Zhang et al.)

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Center for Nuclear Astrophysics (CNA)/SJTU

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Neutrinos in Astrophysics

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Nucleosynthesis

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Neutron Stars

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Laboratory Astrophysics

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Conclusion

Contents

 The exact knowledge of Nuclear Physics is extremely important for understanding a number of fundamental issues of astrophysics and cosmology, and thus the Universe. This constitutes the main contents

• f Nuclear Astrophysics.

Conclusion

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谢 谢！ Than hanks ks!