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

Nuclear Astrophysics at SJTU Lie-Wen Chen ( 陈列文 ) Department of Physics and Astronomy, Shanghai Jiao Tong University, China (lwchen@sjtu.edu.cn)  Center for Nuclear Astrophysics (CNA)/SJTU  Neutrinos in Astrophysics  Nucleosynthesis  Neutron Stars  Laboratory Astrophysics  Conclusion 2015 SJTU- KIT Collaborative Research Workshop “Particles and the Universe”, November 4-6, 2015, SJTU, Shanghai, China

Contents  Center for Nuclear Astrophysics (CNA)/SJTU  Neutrinos in Astrophysics  Nucleosynthesis  Neutron Stars  Laboratory Astrophysics  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

Contents  Center for Nuclear Astrophysics (CNA)/SJTU  Neutrinos in Astrophysics  Nucleosynthesis  Neutron Stars  Laboratory Astrophysics  Conclusion

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 Neutron Supernovae Star Merger Neutron star Gamma-Ray X-Ray Burst Burst  Weak interaction (neutrino) plays an extremely important role for the synthesis of elements in various astrophysical conditions p. 4

Neutrino Astrophysics Potential Signatures of High-Energy Neutrinos Produced by Relativistic Jets in Gamma-Ray Bursts and Core-Collapse Supernovae Gang Guo and Yong-Zhong Qian, 2015  Ultra high energy (Peta-eV) neutrinos have been observed at IceCube  The flavors e and mu are dominant p. 5

Neutrino Astrophysics Potential Signatures of High-Energy Neutrinos Produced by Relativistic Jets in Gamma-Ray Bursts and Core-Collapse Supernovae Gang Guo and Yong-Zhong Qian, 2015 Core-Collapse Supernovae: BH + GRB GRB  HE neutrinos from shocks may annihilate the thermal neutrinos from accretion disk, and thus modify the spectra and flavor of HE neutrinos p. 6

Contents  Center for Nuclear Astrophysics (CNA)/SJTU  Neutrinos in Astrophysics  Nucleosynthesis  Neutron Stars  Laboratory Astrophysics  Conclusion

Element abundance in the solar system p. 7

Nucleosynthesis Formation and evolution of elements in the Universe Gas Dynamics and Chemical Evolution of the Fornax Dwarf Spheroidal Galaxy Zhen Yuan, Yong-Zhong Qian, and Yi-Peng Jing, 2015  Fe fraction is smaller for older stars p. 8

Nucleosynthesis Formation and evolution of elements in the Universe Gas Dynamics and Chemical Evolution of the Fornax Dwarf Spheroidal Galaxy Zhen Yuan, Yong-Zhong Qian, and Yi-Peng Jing, 2015  The fraction of Magnesium, Calcium, and Silicon can be reasonably reproduced by the model (but not for Titanium) p. 9

Synthesis of Heavy Elements p. 10

Synthesis of Heavy Elements 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 - + e 2) Rapid process (r-process) 1) Slow process (s-process) n-capture is faster than β -decay n- capture is slower than β -decay Inside the stars ， Supernovae ， Synthesis → 209 Bi( 铋 ,Z=83) 。 Synthesis → 251 Cf( 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 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 R. Wang and L.W. Chen, PRC92, 031303 (R) (2015) (arXiv:1410.2498)  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. p. 13

Contents  Center for Nuclear Astrophysics (CNA)/SJTU  Neutrinos in Astrophysics  Nucleosynthesis  Neutron Stars  Laboratory Astrophysics  Conclusion

Neutron Stars F. Weber, PPNP54, 193 (2005) Gravity Weak E&M Strong   30 5 Sun: M ; 2 10 kg, R ; 7 10 km e e Stable Neutron Stars    6 Earth: mass 3 10 M , radius=6378km, @beta equilibrium and charge neutrality e   -10 Determined by the 4 forces together compactness M/R 5 10 (M /km) e Interior of NStar: Very dense matter Neutron stars: mass : 1.4 M , radius : 10km, e p. 14 compactness M/R : 0.14 (M /km) e

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. Key Quantity: EOS of neutron star matters Neutron stars consist of β -equilibrium npeμ matter with charge neutrality p. 15

The Symmetry Energy EOS of Isospin Asymmetric Nuclear Matter (Parabolic law)                2 4 E ( , ) E ( ,0) E ym ( ) O ( ), ( ) / s n p Isospin asymmetry Symmetric Nuclear Matter Symmetry energy term (relatively well-determined) (poorly known) Nuclear Matter Symmetry Energy    2 1 E ( , )   E ( )   sym 2 2 2           K L          sym     0 0 E ( ) E ( ) , ( ~ )   sym sym 0 0     3 18 0 0   E ( ) 30 MeV (LD mass formula: My ers & Swiatecki, NPA81; Pomorski & D udek, P R C6 7 ) sym 0   E ( )    sym L 3 (Many- B ody Theo ry: : L 50 ~ 2 0 0 Me V ; Ex p : ???)   0    0   2 E ( )    2 sym K 9 (Many-Body Theory: K : 700 ~ 4 66 Me V ; Exp: ? ?? )   sy m 0 sym 2    0 p. 16

Esym: Experimental Probes Promising Probes of the E sym (ρ) (an incomplete list !) 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 208 Pb  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/ 3 He ratio  Hard photon production  Pigmy/Giant resonances  Nucleon optical potential Towards high densities reachable at CSR/Lanzhou, FAIR/GSI, RIKEN, GANIL and, FRIB/MSU ( 高密度行为 )  π - /π + ratio, K + /K 0 ratio? B.A. Li, L.W. Chen, C.M. Ko  Neutron-proton differential transverse flow Phys. Rep. 464, 113(2008)  n/p ratio at mid-rapidity  Nucleon elliptical flow at high transverse momenta  n/p ratio of squeeze-out emission p. 17