PHYSICS 224 C Nuclear Physics III Experimental High

PHYSICS 224 C Nuclear Physics III - Experimental High Energy You can find this page at http: //nuclear. ucdavis. edu/~cebra/classes/phys 224 c. html QUARTER: Fall 2008 LECTURES: 432 Phys/Geo, TR 2: 10 to 3: 30 INSTRUCTOR: Daniel Cebra, 539 P/G, 752 -4592, cebra@physics. ucdavis. edu GRADERS: none TEXT: No required text. The following could be useful: R. L Vogt Ultrarelativistic Heavy Ion Collisions C. Y. Wong Introduction to High-Energy Heavy-Ion Collisions L. P. Csernai Introduction to Relativistic Heavy Ion Collisions J. Letessier and J. Rafelski Hadrons and Quark-Gluon Plasma HOMEWORK: There will be presentations assigned through the quarter. EXAM: There will be no exams for this course GRADE DETERMINATION: Grade will be determined presentations and class participation OFFICE HOURS: Cebra (any time) Course Overview: The class will be taught as a seminar class. We will alternate between lectures to overview the concepts with readings and discussions of critical papers in the field. There will be no homework assignments, no exams. Students are read the discussion papers ahead and to come prepared for presentations.

Course Outline I. II. I. • • a. b. c. d. e. I. II. III. IV. Overview and Historical Perspective Hagedorn Bootstrap Model Bjorken energy density Basic Kinematics Quantum Chromodynamics Asymptotic freedom Confinement Chirality Drell-yan Initial Conditions and First Collisions Glauber Model --- pre-collision and initial geometry (impact parameter) Color-Glass Condensate Parton Cascade --- Quark-Gluon Plasma Formation and Evolution Lattice QCD Hydrodynamics Elliptic flow Probes of the Dense Partonic Phase J/y Suppression and open charm Upsilon Jets Direct Photons Di-Leptons Hadronization Recombination vs. Fragmentation Chemical Equilibrium, Chemical freeze-out Strangeness enhancement Thermal Freeze-out Pion production/Entropy Radial Flow HBT Implications Big Bang Cosmology BBN Supernovae Neutron, Strange, and Quark Stars

Broad Historic Developments 1896 Discovery of Radioactivity (Becquerel) 1911 Nuclear Atom (Rutherford) 1932 Discovery of the neutron (Chadwick) 1935 Meson Hypothesis (Yukawa) 1939 Liquid-Drop model of nucear fission (Bohr and Wheeler) 1947 Discovery of the pion (Powell) 1949 Nuclear Shell Model (Mayer and Jensen) 1953 Strangeness Hypothesis (Gell-Mann and Nishjima) 1953 First production of strange particles (Brookhaven) 1955 Discovery of the anti-proton (Chamberlain and Segre) 1964 Quark model of hadrons (Gell-Mann and Zweig) 1967 Electroweak model proposed (Weinberg and Salam) 1970 Charm hypothesis (Glashow) 1974 Discovery of the J/y (Ricther, Ting) 1977 U Discovered and bottom inferred (Lederman) 1980 First Quark Matter meeting (Darmstadt, Germany) 1983 W and Z discovered (Rubbia) 1983 Isabelle cancelled 1984 RHIC Proposal 1986 Heavy-ion operations at the AGS and SPS 1992 Au beams at the AGS and Pb beams at the SPS 1995 Top quark observed (Fermilab) 2000 Au+Au operations at RHIC 2009? Pb+Pb operations at the LHC 10/7/2020 Physics 224 C – Lecture 1 -- Cebra 3

A brief history of relativistic heavy-ion facilities LBNL – Bevalac (1980 – 1992) [Au 0. 1 to 1. 15 AGe. V] EOS --- TPC : DLS --- Di. Lepton spectrometer GSI – SIS () [] TAPS: Kao. S: Fo. Pi BNL – AGS (1986 -1995) [Si, 1994 Au 10 AGe. V, 8, 6, 4, 2] E 802/866/917; E 810/891; E 877; E 878; E 864; E 895; E 896 CERN – SPS (1986 -present) [O 60, 200 AGe. V (1986 -87); S 200 AGe. V (1987 -1992): Pb 158, 80, 40, 30, 20 AGe. V (1994 -2000), In] HELIOS(NA 34); NA 35/NA 49/NA 61(Shine); NA 36; NA 38/NA 50/NA 60; NA 44; CERES(NA 45); NA 52 WA 85/WA 94/WA 97/NA 57; WA 80/WA 9898 BNL – RHIC (2000 -present) [Au+Au 130, 200, 62. 4, 19. 6, d+Au 200, Cu+Cu 200, 62. 4, 22, p+p 200, 450] STAR PHENIX Phobos BRAHMS pp 2 pp CERN – LHC (2009? )[Pb+Pb] ALICE CMS ATLAS 10/7/2020 Physics 224 C – Lecture 1 -- Cebra 4

Quark-Gluon Plasma 10/7/2020 Physics 224 C – Lecture 1 -- Cebra 5

Motivation for Relativistic Heavy Ion Collisions Two big connections: cosmology and QCD

The phase diagram of QCD Temperature Early universe Tc critical point ? quark-gluon plasma colour superconductor hadron gas nuclei CFL vacuum r 0 baryon density Neutron stars

Evolution of Forces in Nature

Going back in time… Age 0 10 -35 s Energy Matter in universe 1019 Ge. V grand unified theory of all forces 1014 Ge. V 1 st phase transition (strong: q, g + electroweak: g, l, n) 10 -10 s 102 Ge. V 2 nd phase transition (strong: q, g + electro: g + weak: l, n) 10 -5 s RHIC, LHC & FAIR 0. 1 Me. V RIA & FAIR nuclei 0. 2 Ge. V 3 rd phase transition (strong: hadrons + electro: g + weak: l, n) 3 min. 6*105 years 0. 3 e. V Now (1. 5*109 years) 3*10 -4 e. V = 3 K atoms

Connection to Cosmology • Baryogenesis ? • Dark Matter Formation ? • Is matter generation in cosmic medium (plasma) different than matter generation in vacuum ?

Sakharov (1967) – three conditions for baryogenesis • Baryon number violation • C- and CP-symmetry violation • Interactions out of thermal equilibrium • Currently, there is no experimental evidence of particle interactions where the conservation of baryon number is broken: all observed particle reactions have equal baryon number before and after. Mathematically, the commutator of the baryon number quantum operator with the Standard Model hamiltonian is zero: [B, H] = BH - HB = 0. This suggests physics beyond the Standard Model • The secondition — violation of CP-symmetry — was discovered in 1964 (direct CP-violation, that is violation of CP-symmetry in a decay process, was discovered later, in 1999). If CPTsymmetry is assumed, violation of CP-symmetry demands violation of time inversion symmetry, or T-symmetry. • The last condition states that the rate of a reaction which generates baryon-asymmetry must be less than the rate of expansion of the universe. In this situation the particles and their corresponding antiparticles do not achieve thermal equilibrium due to rapid expansion decreasing the occurrence of pair-annihilation.

Dark Matter in RHI collisions ? Possibly (not like dark energy) The basic parameters: mass, charge

Basic Thermodynamics Hot Hot Cool Sudden expansion, fluid fills empty space without loss of energy. d. E = 0 Pd. V > 0 therefore d. S > 0 Gradual expansion (equilibrium maintained), fluid loses energy through Pd. V work. d. E = -Pd. V therefore d. S = 0 Isentropic Adiabatic

Nuclear Equation of State

Nuclear Equation of State

Golden Rule 1: Entropy per co-moving volume is conserved Golden Rule 2: All entropy is in relativistic species Expansion covers many decades in T, so typically either T>>m (relativistic) or T<<m (frozen out) Golden Rule 3: All chemical potentials are negligible Golden Rule 4:

g*S 1 Billion o. K 1 Trillion o. K Start with light particles, no strong nuclear force

g*S 1 Billion o. K 1 Trillion o. K Previous Plot Now add hadrons = feel strong nuclear force

g*S 1 Billion o. K 1 Trillion o. K Previous Plots Keep adding more hadrons….

How many hadrons? Density of hadron mass states d. N/d. M increases exponentially with mass. TH ~ 2 1012 o. K Broniowski, et. al. 2004 Prior to the 1970’s this was explained in several ways theoretically Statistical Bootstrap Hadrons made of hadrons… Regge Trajectories Stretchy rotators, first string theory

Hagedorn Limiting Temperature Ordinary statistical mechanics For thermal hadron gas (somewhat crudely): Energy diverges as T --> TH Maximum achievable temperature? “…a veil, obscuring our view of the very beginning. ” Steven Weinberg, The First Three Minutes (1977) Rolf Hagedorn German Hadron bootstrap model and limiting temperature (1965)

What do I mean “Bjorken”? Boost-invariant Increasing E y y d. N/dy’ “Inside-out” & 1 dimensional y’=y-ybeam 0

Impact of “Bjorken” X X • d. N/dy distribution is flat over a large region except “near the target”. • v 2 is independent of y over a large region except “near the target”. (2 d-hydro. ) • p. T(y) described by 1 d or 2 d-hydro. • Usual HBT interpretation starts from a boostinvariant source. • T(t) described by 1 d-hydro. • Simple energy density formula

Notations We’ll be using the following notations: proper time and rapidity

Most General Boost Invariant Energy-Momentum Tensor The most general boost-invariant energy-momentum tensor for a high energy collision of two very large nuclei is (at x 3 =0) which, due to gives There are 3 extreme limits.

Limit I: “Free Streaming” Free streaming is characterized by the following “ 2 d” energy-momentum tensor: such that and Ø The total energy E~ e t is conserved, as expected for non-interacting particles.

Limit II: Bjorken Hydrodynamics In the case of ideal hydrodynamics, the energy-momentum tensor is symmetric in all three spatial directions (isotropization): such that Using the ideal gas equation of state, , yields Bjorken, ‘ 83 Ø The total energy E~ e t is not conserved, while the total entropy S is conserved.

Most General Boost Invariant Energy-Momentum Tensor If then, as , one gets Deviations from the like . scaling of energy density, are due to longitudinal pressure , which does work in the longitudinal direction modifying the energy density scaling with tau. Ø Non-zero positive longitudinal pressure and isotropization ↔ deviations from

Limit III: Color Glass at Early Times In CGC at very early times such that, since Energy-momentum tensor is (Lappi, ’ 06) we get, at the leading log level,

Replace Hadrons (messy and numerous) by Quarks and Gluons (simple and few) “In 1972 the early universe seemed hopelessly opaque…conditions of ultrahigh temperatures…produce a theoretically intractable mess. But asymptotic freedom renders ultrahigh temperatures friendly…” Frank Wilczek, Nobel Lecture (RMP 05) D. Gross H. D. Politzer F. Wilczek American QCD Asymptotic Freedom (1973) e/T 4 g*S Thermal QCD ”QGP” Hadron gas QCD to the rescue! (Lattice) Karsch, Redlich, Tawfik, Eur. Phys. J. C 29: 549 -556, 2003

Nobel prize for Physics 2005 e+e- Annihilation Nucleosynthesis Mesons freeze out QCD Transition g*S Heavy quarks and bosons freeze out Thermal QCD -- i. e. quarks and gluons -makes the very early universe tractable; but where is the experimental proof? n Decoupling “Before [QCD] we could not go back further than 200, 000 years after the Big Bang. Today…since QCD simplifies at high energy, we can extrapolate to very early times when nucleons melted…to form a quark-gluon plasma. ” David Gross, Nobel Lecture (RMP 05) Kolb & Turner, “The Early Universe”

The main features of Quantum Chromodynamics • • • Confinement – At large distances the effective coupling between quarks is large, resulting in confinement. – Free quarks are not observed in nature. Asymptotic freedom – At short distances the effective coupling between quarks decreases logarithmically. – Under such conditions quarks and gluons appear to be quasi-free. (Hidden) chiral symmetry – Connected with the quark masses – When confined quarks have a large dynamical mass - constituent mass – In the small coupling limit (some) quarks have small mass - current mass

Quarks and Gluons

Basic Building Blocks ala Halzen and Martin

Quark properties ala Wong

What do we know about quark masses ? Why are quark current masses so different ? Can there be stable (dark) matter based on heavy quarks ?

Elementary Particle Generations

Some particle properties

Elemenary particles summary

Comparing QCD with QED (Halzen & Martin)

Quark and Gluon Field Theory == QCD (I)

Quark and Gluon Field Theory == QCD (II)

Quark and Gluon Field Theory == QCD (III) • Boson mediating the q-qbar interaction is the gluon. • Why 8 and not 9 combinations ? (analogy to flavor octet of mesons) – – R-Bbar, R-Gbar, B-Rbar, G-BBar 1/sqrt(2) (R-Rbar - B-Bbar) 1/sqrt(6) (R-Rbar + B-Bbar – 2 G-Gbar) Not: 1/sqrt(3) (R-Rbar + G-Gbar + B-Bbar) (not net color)

Hadrons

QCD – a non-Abelian Gauge Theory

Particle Classifications

Quarks

Theoretical and computational (lattice) QCD In vacuum: - asymptotically free quarks have current mass - confined quarks have constituent mass - baryonic mass is sum of valence quark constituent masses Masses can be computed as a function of the evolving coupling Strength or the ‘level of asymptotic freedom’, i. e. dynamic masses. But the universe was not a vacuum at the time of hadronization, it was likely a plasma of quarks and gluons. Is the mass generation mechanism the same ?

Confinement Represented by Bag Model

Bag Model of Hadrons

Comments on Bag Model

Still open questions in the Standard Model

Why RHIC Physics ?

Why RHIC Physics ?