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Nuclear matter

Nuclear matter. 1) Introduction 2) Nuclear matter in the ground state 3) Hot and den s e nuclear matter 4) State equation of nuclear matter 5) Phase diagram and phase transitions 6) Study of hot and den s e nuclear matter properties 7) Collision of relativistic heavy nuclei

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Nuclear matter

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  1. Nuclear matter 1) Introduction 2) Nuclear matter in the ground state 3) Hot and dense nuclear matter 4) State equation of nuclear matter 5) Phase diagram and phase transitions 6) Study of hot and dense nuclear matter properties 7) Collision of relativistic heavy nuclei 8) Quark-gluon plasma Simulation of creation of hot and dense nuclear matter zone in the heavy ion collisions

  2. Introduction What do we study? Study of properties of unlimited block of nuclear matter → necessity to separate influence of: 1) reaction dynamics 2) finality of nuclear matter volume Study of thermodynamic properties (state equation) of nuclear matter in different conditions, phase transitions between different states of nuclear matter: 1) In the ground state2) Hot and dense state Why do we study? In very dense and hot state → important for understanding of properties of matter during Universe creation and inside of many astrophysical objects Very high density and temperature → possibility of quark-gluon plasma creation Matter in very dense and hot state can be at active galaxy centers – picture of one Seyfert galaxy – obtained by Hubble telescope (NASA)

  3. How do we study? Nuclear physics: In the ground state - giant resonances – vibration of nuclei depends on nuclear matter compressibility Hot and dense – heavy ion collisions  compression and heating of nuclear matter Collisions of the heaviest nuclei with different energies – achievement of the highest – present top is RHIC at Brookhaven, LHC at CERN (2007) Experiment for hot and dense nuclear matter studies ALICE prepared for LHC accelerator build up at laboratory CERN Astrophysics – research of neutron star properties (stability, dependency of size on mass) and history of supernova explosion Supernova explosion remnant at Large Magellanic Cloud – Hubble telescope picture (NASA)

  4. Nuclear matter in the ground state Usual nuclear matter (mixture of protons and neutrons): Information about binding energy of nuclear matter for T=0 and ρ=ρ0 → volume contribution at Weizsäcker formula (drop model) determines binding energy B/A = 16 MeV Studies of equation of state of nuclear matter at ground state → history of nuclear vibration is given by nuclear matter compressibility: • oscillations (volume increasing and decreasing) of nucleus • giant dipole resonances – relative motion of proton and neutron liquid • vibration of nucleus Oscillations Giant dipole resonances Vibrations Description of nuclear matter – QCD calculation on the lattice using quantum chromodynamics Dependency of nuclear matter properties on ratio between proton and neutron numbers (isotopic composition) Neutron liquid in the ground state:Occurrence inside neutron stars. Nuclear matter with strangeness in the ground state: Influence of strangeness on nuclear matter properties – interaction between lambda particles - Brookhaven (system consisted of proton, neutron and two lambdas) Occurrence - maybe inside neutron stars.

  5. Hot and dense nuclear matter Necessity of nuclear matter study not only at the ground state but also for different temperatures (energy densities) and densities Temperature increasing → increasing of kinetic energy of nucleons → transformation of kinetic energy to excitation energy → phase transitions between different forms of nuclear matter: • excitation of nucleons to resonances (Δ a N*) • higher temperature (energy density) → transition from nuclear liquid to hadron gas • 3) even higher → quark-gluon plasma Can be studied from the history of compression, heating and following expansion during atomic nuclei collisions with high energy ( E > 100 MeV/A) ↔  permeation of colliding nuclei does not happen (confirmed by Bevalac during seventies) Device for study of heavy nucleicollision FOPI on SIS accelerator – energy ~ 1 GeV/A

  6. B/A[MeV/nucleon] ρ[nucleon/fm3] Equation of state of nuclear matter Nuclear matter properties can be described at equilibrium state by two variables density ρ and temperature T and equation of state, which is relation for pressure P = f(ρ,T).We use energy per one nucleon E/A instead of pressure and we fix temperature: E/A=f(ρ) |T=const Relation between pressure and temperature is (for equilibrium state entropy S isconstant): For T = 0 minimum E/A = -B/A = -16 MeVwill beforρ0 = 0.16 nucl./fm-3 (2.6∙1017 kg/m3) Nuclear matter equation of state E/A = f(ρ) for different variants of stiffness

  7. Radius of curvature of functionE/A = f(ρ)forρ → ρ0where isminimum of energy and then it is valid: it gives nuclear matter compressibility (K =compression module): Compressibility is defined in classical thermodynamics byequation (change of pressure as dependency on relative change of density): Nuclear physics → we are working with number of nucleon density and binding energy per nucleon. Compressibility we involve in the form: We substitute expression for pressure: In minimum region ρ = ρ0 → : Larger energy change with density change → larger resistance against compression → harder equation of state K > 290 MeV → hard equation of stateK < 290 MeV → soft equation of state Stiffness of equation of state depends on shape of central part of nuclear potential (its repulsive part) Experiments with α particles scattering on Sm nuclei → K ~ 240 MeV

  8. Early Universe Quark-gluon plasma hadron gas gas-plasma coexistence early universe Temperature vapor nuclear liquid nuclear collision quark-gluon plasma nuclear condensate Neutron star plasma Temperature hadron gas Baryon density nuclear condensate atomic nucleus nuclear liquid Density strangelets ice water neutron star Phase diagram and phase transitions Nuclear matter can be in different phasesfor different densities, temperatures or also strangeness. Phase and phase transitions between them can be displayed by phase diagram: • phase transition of nuclear liquid to hadron gas TC 5 MeV • 2) phase transition from hadron gas to quark-gluon plasma TC 200 MeV, ρC  5-8 ρ0) Phase diagram of nuclear matter with marking of different phases and phase transitions

  9. Temperature Temperature Temperature Energy density Energy density Energy density Phase transitions. We have three transition types – different dependency of temperature changes (TC - critical temperature – temperature of phase transition): First order transition: Second order transition:Continuous transition: I. order transition: 1) parallel existence of two phases during phase transition 2) existence of overcooled or superheated forms of matter in appropriate phase 3) stopping of parameter changes (temperature, increasing of expansion) II. order transition: 1) impossibility of parallel existence of two phases

  10. Hadron gas Nuclear matter Nuclear liquid Potential Temperature JINR Distance Energy Potential Distance Phase transition of nuclear liquid in hadron gas. Similarity of potential shape  similarity between phase transition of nuclear matter (nuclear liquid  hadron gas) and H2O (water to water vapor) Device ALADIN at GSI Darmstadt, where phase transition of nuclear liquid to hadron gas was studied Vapor Temperature [oC] Water Energy [meV/molecule] Phase transitions of nuclear matter and water (H2O) and shape of appropriate potentials

  11. Study of hot and dense nuclear matter properties Necessity of determination of physical quantities – density, temperature and changes of nuclear matter physical properties as function f = f(ρ,T) Nuclear methods: Collisions of heavy nuclei → creation of hot and dense nuclear matter zone Determination of temperature in different moments: spectra of different particles Determination of density Determination of equation of state stiffness (compressibility coefficient): Collision history (expansion history and asymmetry of particle emission) Detector STAR working on RHIC accelerator (colliding beams of heavy nuclei with 200 GeV/nucleon) and reconstruction of collision by this experiment Astrophysical methods: 1) Study of neutron star properties Determination of density (mass, volume – ρ = ρ(r) ) Determination of temperature using spectrum (surface – inside is more difficult) Stability depends on equation of state of neutron liquid 2) Study of supernova explosion history Explosion history depends on nuclear matter equation of state Released energy magnitude, character of emitted spectrum

  12. Signs of quark-gluon plasma creation: First evidence of observation of quark-gluon plasma creation on SPS accelerator at CERN. NA44, NA45/CERES, NA49, NA50, NA52, NA57/WA97 and WA98experiments report togetherdiscovery of this matter at year 2000. Thousands of particles are created during collisions. Most of them is necessary detect and determine their properties. Comparison with p-p collisions results after normalization on number of nucleon-nucleon collisions Experiments on SPS at CERN observe: 1) Achievement of needed temperature and energy density 2) History of expansion 3) Increasing of strange particle production 4) Suppression of J/ψ meson production 5) Chiral symmetry restoration Observation of new phenomena on RHIC accelerator at years 2002 – 2004: 6) Jet production suppression Collision of acceleratedlead nucleuswithtarget nucleus, NA49 experimenton SPS accelerator (158 GeV/n) Transition fromfixedtargettocollidingbeams: Energy accessible in centre of mass: Collision of gold nuclei at STAR experimenton RHICaccelerator of colliding beams ( 100 + 100 GeV/a ) SPS RHIC 13 GeV/n 200 GeV/n

  13. Quark Jet Quark Jet Jet production – visualization of quarks Collision of quark with very high energy → creation of couple of directed flow of particles interacting by strong interaction - „jets" Example of four jet creation observed by OPAL experimenton LEP accelerator (Searching of Higgs particle) Quark with very high energy creates great number of quark antiquark pairs they hadronised later Created hadron jet has direction and total energy of original quark

  14. Suppression of jet production (jet quenching) ? Nucleus-nucleus collision: jet production is influenced by these phenomena: 1) Cronin effect– multiple scattering→ smear of transverse momenta → shift to higher pt→ production increasing 2) Saturation – big parton density → decreasing of jet production increasing with energy lower energies higher energies 3) Suppression of jet production (particles with high pt) and jet pairs Passage of jet partons throughquark-gluon plasma(QGP) → energy and momentum losses→ jet suppression (they are not in normal hadron mass) → proof of QGP creation Observed by experiments on RHIC accelerator Jet productions in different collisions were compared: 1) d-Au - QGP can not be created → only saturation and Cronin effect 2) Au-Au - QGP can be created → also production suppression Suppression of jet pair production is observed only in Au-Au collisions → QGP is created

  15. Croninův jev i potlačení výtrysků Konečná data Konečná data Předběžná data Předběžná data Croninův jev i potlačení výtrysků pouze Croninův jev Konečnádata Předběžnádata Konečnádata Předběžnádata pouze Croninův jev Suppression of particles with high transversal momentum Experimental results: Dramatic difference of behavior in the case of Au+Au and d+Au collisions as dependency on collision centrality RAA – relation between numbers of measured and extrapolated from nucleon-nucleon collisions Au + Au experiment d + Au control experiment Experiment Phenix

  16. What further? Necessity of study of properties of new matter state – its equation of state Some properties agrees with original assumptions about quark-gluon plasma, some are nearer to „color glass condensate“ Determination of phase transition order – big importance for Big Bang history We study so far only strongly interacting particles (99,9 % created particles are hadrons), photons and leptons only from secondary processes → indirect signals – information is partly loosed Urgent study of photons and leptons created directly in plasma → direct signals from quark-gluon plasma RHIC 200 + 200 GeV/nucleon LHC 3500 + 3500 GeV/nucleon

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