Constraining neutron star matter with laboratory experiments Crab Pulsar 2005 APS April Meeting Tampa FL Betty Tsang The National Superconducting Cyclotron Laboratory @Michigan State University.
Download ReportTranscript Constraining neutron star matter with laboratory experiments Crab Pulsar 2005 APS April Meeting Tampa FL Betty Tsang The National Superconducting Cyclotron Laboratory @Michigan State University.
Constraining neutron star matter with laboratory experiments Crab Pulsar 2005 APS April Meeting Tampa FL Betty Tsang The National Superconducting Cyclotron Laboratory @Michigan State University Birth of a Neutron Star July 4, 1054, China July 5, 1054, N. America Outline: Structure of NS and EOS Experimental constraints NS observations (M, R, T) Nuclei Heavy Ion Collisions (<O) Current status: n/p ratios isotope distributions isospin (N/Z) diffusion Heavy Ion Collisions (>O) n/p flow +/- ratios … Size & Structure of Neutron Star depends on EOS Dense neutron matter. Strong mag. field. Strange composition pasta and anti-pasta phases; kaon/pion condensed core … EOS influence R,M relationship maximum mass. Free Fermi gas EOS: mass < 0.7 M cooling rate. core structure D. Page What is known about the EOS of symmetric matter E(, d) = E(, d=0) + Esym(,d) d2 Pressure (MeV/fm3) Danielewicz, Lacy, Lynch, Science 298,1592 (2002) d = (n - p)/(n + p) Not well constrained • Relevant for supernovae - what about neutron stars? B = aV A aS A 2/ 3 Z ( Z 1) ( A 2Z )2 + d aC a sym 1/ 3 A A (a sym A a sym A Proton Number Z V S 2/3 ( A 2Z ) 2 ) A2 Inclusion of surface terms in symmetry Neutron Number N Parity violating e- scattering: Rn(208Pb) JLAB (2005) Heavy ion collisions : Access to high density nuclear matter Danielewicz, Lacy, Lynch, Science 298,1592 (2002) Results from Au+Au flow (E/A~1-8 GeV) measurements include constraints in momentum dependence of the mean field and NN crosssections R. Lacey Heavy ion collisions : Access to low density nuclear matter E/A<100 MeV; Multifragmentation Scenario P T --Initial compression and energy deposition -- Expansion – emission of light particles. -- Cooling – formation of fragments -- Disassembly Model Approaches Dynamical and Statistical Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Sn+Sn; E/A=50 MeV; b=0 fm Micha Kilburn REU 2003 BUU: Transport theory based on Boltzmann Equations Observables in HI collisions Assume Esym()( /0)g Heavy Ion Collisions (Ntot/Ztot>1): Central collisions (isospin fractionation) n/p ratios; <En>, <Ep> Bound matter Isotope distributions Peripheral Collisions Isospin diffusion The symmetry term affects the N/Z composition of the dense region. Stiff g~2 : N/Zres~Ntot/Ztot Soft g~0.5: N/Zres<Ntot/Ztot n/p Experiment 124Sn+124Sn; 112Sn+112Sn; E/A=50 MeV 420-620 80-380 Scattering Chamber Famiano et al N-detection – neutron wall p-detection: Scattering Chamber WU MicroBall (b determination) ~6in central bˆ 0.2 # of charged particles 3 particle telescopes (p, d, t, 3He, …) n-TOF start detector n/p Double Ratios (central collisions) Double Ratio 124Sn+124Sn;Y(n)/Y(p) 112Sn+112Sn;Y(n)/Y(p) minimize systematic errors Data, Famiano et al, preliminary Double Ratio g~0.5 soft g~1.1 stiff BUU: Li, Ko, & Ren PRL 78, 1644, (1997) Center of mass Energy There will be improvements in both data (analysis) and BUU (1997) calculations. Observables in HI collisions Assume Esym()( /0)g Heavy Ion Collisions (Ntot/Ztot>1): Central collisions (isospin fractionation) n/p ratios; <En>, <Ep> RES Isotope distributions Stiff g~2 : N/Zres~Ntot/Ztot Soft g~0.5: N/Zres<Ntot/Ztot Isotope Distribution Experiment MSU, IUCF, WU collaboration Sn+Sn collisions involving 124Sn, 112Sn at E/A=50 MeV Miniball + Miniwall 4 multiplicity array Z identification, A<4 LASSA Si strip +CsI array Good E, position, isotope resolutions Measured Isotopic yields T.X Liu et al. PRC 69,014603 Central collisions P T Similar distributions R21(N,Z)=Y2(N,Z)/ Y1(N,Z) Isoscaling from Relative Isotope Ratios R21(N,Z) =Y2(N,Z)/ Y1(N,Z) eN + Z MB Tsang et al. PRC 64,054615 Isoscaling : R21=Y2/ Y1 eN + Z Observed in many reactions by many groups. 112Sn+58Ni and 124Sn+64Ni at 35 AMeV; Central collisions, CHIMERA-REVERSE experiment E. Geraci et al., Nucl. Phys. A732 (2004) 173 Shetty et al, PRC68,021602(2003) Derivation of isoscaling from Grand Canonical ensemble Yields term with exponential dependence on n, p Y ( N , Z ) HOT exp ( n N + p Z + B( N , Z ) / T ) Z int ( N , Z ) * 3 ( ) where Z = 2 J + 1 exp( E ) Saha Equation i i int i /3T /2 2 2 ( A1) 2feeding correction Z N A1 A B(Z,N)/kT Y ( Z , N ) = Y p Yn G ( Z , N )( N A ) e A ) Y ( N , Z )COLD = Y ( N , Z ) HOT f ( N2, Z m kT u BE and Zint terms cancel for constant T Ratios of Y (N,Z) from 2 systems observe isoscaling R21 (N , Z ) = Y2 ( N , Z ) N n / T + Z p / T C e Y1 ( N , Z ) = n / T , = p / T slopes are related to symmetry energy source asymmetry = 2Csym (d1 d 2 )(1 d ) / T d1 = ( N o,1 Z o,1 ) / Ao,1 d = (d1 + d 2 ) / 2 Reproduced by all statistical and dynamical multifragmentation models Density dependence of symmetry energy Central collisions of 124Sn+ 124Sn & 112Sn+ 112Sn at E/A=50 MeV Isoscaling slope EES Data – isotope yields N + Z Y2/ Y1=C e =isoscaling slope Need a model to relate with g. g~0.5-0.85 Assume E()=23.4(/o)g in a statistical model using rate equations to describe fragment emissions. Tsang et al, PRL, 86, 5023 (2001) Observables in HI collisions Peripheral Collisions Isospin diffusion Symmetry energy will act as a driving force to transport the n or p from projectile to target or vice versa via the neck region. 112Sn 124Sn N/Z Diffusion? Coulomb? Pre-equilibrium? Theoretical observable? (112Sn residue) < (124Sn residue) Isospin Transport Ratio Isospin diffusion occurs only in asymmetric systems A+B No isospin diffusion between symmetric systems 124 112 124 112 124 112 Non-isospin diffusion effects same for A in A+B & A+A ;same for B in B+A & B+B 2 x AB x AA xBB Rami et al., PRL, 84, 1120 (2000) Ri = x AA xBB xAB=xAA Ri = 1. =2Csymd(1-d)/T; xAB=xBB Ri = -1. d = (N-Z)/(N+Z) xAB=experimental or theoretical isospin observable for system AB Experimental: xAB= Theoretical : xAB= d Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 Lijun Shi g~1.1 g~0.5 g~1.1 g~0.5 Lijun Shi Tsang et al., PRL92(2004) Experimental Results 124 124 124 112 112 124 112 112 0.57 0.44 0.13 0.0 b=>0.8 Y/ybeam>0.7 Experimental Results Ri 124 124 124 112 112 124 112 112 1.0 0.47 -0.45 -1.0 b=>0.8 Y/ybeam>0.7 Constraints on symmetry term in EOS from isospin diffusion E(, d) = E(, 0) + Esym()d2; d=(n-p )/(n+p ) Assume Esym()( /0)g BUU+m*: Transport theory based on Boltzmann Equations & include momentum dependence in mean field. g~0.6-1.6 112,124Sn+ 112,124Sn E/A=50 MeV Peripheral collisions g Experimental constraints on symmetry energy using heavy ion collisions /0=0.3-1.0; Esym ~ C(/0)g Isotope distributions: g~0.5-0.85 (simplistic calculations) Isospin (N/Z) diffusion: g~0.6-1.5 Can expect significant improvements in these constraints Expt : n/p ratios – preliminary, n/p flow, PP correlations Theory: Better transport calculations NS properties? Steiner: nucl-th0410066 for 1.4 M.⃝ RNS>12 km Experiments at Rare Isotope Accelerator can provide constraints at higher densities (~O -2O) Acknowledgements Theorists: W. Friedman (Wisconsin, Madison) P. Danielewicz (MSU), S. Das Gupta (McGill, Canada), A. Ono (Tokohu, Japan), L. Shi (MSU), M. Kilburn (MSU) Experimentalists: HiRA collaboration Michigan State University T.X. Liu (thesis), M. Famiano (n/p expt), W.G. Lynch, W.P. Tan, G. Verde, A. Wagner, H.S. Xu Washington University L.G. Sobotka, R.J. Charity Inidiana University R. deSouza, S. Hudan, V. E. Viola