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Research Frontiers in Nuclear Physics. Central truths of nuclear physics driving research for more than one century. We are nothing (c. 1900). We are dust (c. 1950). We don’t matter (c. 2000). Atom. Nucleus. (“ion” when alone). Proton. Neutron. Quarks. Held together. by gluons.

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Research frontiers in nuclear physics

Research Frontiers in Nuclear Physics

Central truths of nuclear physics

driving research for more than one century

  • We are nothing (c. 1900)

  • We are dust (c. 1950)

  • We don’t matter (c. 2000)


We are nothing

Atom

Nucleus

(“ion” when alone)

Proton

Neutron

Quarks

Held together

by gluons

(not shown)

We are nothing !

Most of “us” is (nearly) empty space

  • 99.9% of the mass of atoms is contained in the nucleus

  • The nucleus is about 10-12 of the size of the atom

  • Nuclear density 1014 times larger than density of water

birth of nuclear physics

Axel Drees


Nuclear zoology and the nuclear chart

protons

p n

100

82

50

126

50

20

82

50

8

20

2

neutrons

50

100

8

2

Nuclear Zoology and the Nuclear Chart

  • Categorize properties of nuclei and present in nuclear chart

Fermi gas model

Coulomb repulsion of protons

valley of stability

near Z = N

No stable nuclei

beyond 208 Pb

limited range

of nuclear force

Magic Z and N numbers with many stable nuclei

Indication of shell structure

Axel Drees


Going to the extremes of nuclear structure

114

184

Going to the Extremes of Nuclear Structure

  • The many body problem

    • Nucleus is complex system of many strongly interacting particles

    • Needs to be treated microscopically

    • Remains one of the major theoretical challenges

  • Search for super heavy nuclei

    • Island of stability near next shell closer

    • The ultimate test of shell models

    • Element 112 discovered at GSI

      “Ununbiium”

  • Nuclei with extreme angular momentum

    • Sensitive test of shell models

    • Actively pursued by Prof. Fossan and Starosta at Stony Brook NSL and other facilities

Axel Drees


We are dust

~ 100 s after Big Bang

Nucleon Synthesis

strong force binds protons and neutrons bind into light nuclei

He to Li

We are dust !

Most elements create in stellar catastrophes long after big bang

Elements up to Fe fussed in Stars

Heavy elements created in super nova explosions

We are mostly stardust !

Axel Drees


Nuclei far from stability
Nuclei far from Stability

  • Explore “Terra Incognita” to proton and neutron drip line

    • Important for creation of heavy elements in Supernovae

    • Proton rich created with stable beams

    • Neutron rich require radio active beams

    • Neutron rich nuclei only created

      with radioactive beams

    • Interesting Atomic physics

    • ongoing experiments in NSL

      (Prof. Sprouse & Orozco)

  • Rare Isotope Accelerator

    new $800M US project

Axel Drees


We don t matter
We don’t matter !

  • More accurately: We’re not matter

  • Nearly all the mass of each atom is concentrated in the nucleus:

    • Each nucleus consists of neutrons and protons

    • Each neutron and proton consists of 3 quarks

    • Each quark has the mass of 5-7 MeV/c2

      ~ 1% of a proton or neutron(!)

    • The rest of the mass of protons and neutrons (and hence our mass)

      is “frozen energy” from the Big Bang

Axel Drees


The big freeze

~ 10 ms after Big Bang

Hadron Synthesis

strong force binds

quarks and gluons in massive objects:

protons, neutrons mass ~ 1 GeV/c2

~ 100 s after Big Bang

Nucleon Synthesis

strong force binds protons and neutrons bind in nuclei

The Big Freeze

Axel Drees


Fundamental puzzles of hadrons
Fundamental Puzzles of Hadrons

nuclear matter

p, n

  • Confinement

    • Quarks do not exist as free particles

  • Large hadron masses

    • Free quark mass ~ 5-7 MeV

    • Quarks become “fat” in hadrons constituent mass ~ 330 MeV

  • Complex structure of hadrons

    • Sea quarks and anti quarks

    • Gluons

    • “spin crisis”

      Spin of protons not carried by quarks!

Go back in time to big bang

Feasible in heavy ion collisions

Measurement with polarized proton beams at high energy

All addressed at RHIC

Axel Drees


Travel back in time
“Travel” Back in Time

  • QGP in Astrophysics

    • early universe after ~ 10 ms

    • possibly in neutron stars

  • Relativistic

  • Heavy

  • Ion

  • Collider at BNL

  • Quest of heavy ion collisions

    • create QGP as transient state in heavy ion collisions

    • verify existence of QGP

    • Study properties of QGP

    • study QCD confinement and how hadrons get their masses

  • Axel Drees


    Detecting the qgp matter box

    vacuum

    QGP

    Detecting the QGP “matter box”

    • “ideal” experiment

    • Rutherford experiment a atom discovery of nucleus

      SLAC electron scattering e  proton discovery of quarks

    • Experiments with QGP not quite that simple

      • QGP created in nucleus-nucleus collisions can not be put in “box”

      • Thousands of particles produced during collision

    penetrating beam

    absorption or scattering pattern

    Axel Drees



    A silly analogy
    A Silly Analogy

    • Suppose…

      • You lived in a frozen world where there’s only as ice

      • and the ice is quantized in ice cubes

      • Some weird physicists tell you there should be water

      • and suggest to heat the ice by colliding two ice cubes

      • So you form a “bunch” containing a billion ice cubes

      • which you collide with another such bunch

      • 10 million times per second

      • which produces about 1000 IceCube-IceCube collisions per second

      • which you observe from the vicinity of Mars

    • Change the length scale by about 10 trillion

      • You’re doing physics at RHIC!

    Axel Drees


    R elativistic h eavy i on c ollider

    BRAHMS

    PHOBOS

    STAR

    PHENIX

    Relativistic Heavy Ion Collider

    RHIC

    Axel Drees


    • 11 nations

    • 51 institutions

      Stony Book:

      Prof. Averbeck, Drees, Jacak, Hemmick

    Axel Drees


    Phenix at rhic
    PHENIX at RHIC

    • 2 central spectrometers

    West

    • 2 forward spectrometers

    South

    East

    • 3 global detectors

    North

    Axel Drees


    Phenix central
    PHENIX Central

    East Carriage

    Ring Imaging Cerenkov

    Drift Chamber

    Central Magnet

    West Carriage

    Axel Drees


    Space time evolution of collisions

    p

    L

    e

    p

    K

    p

    jet

    J/Y

    g

    Freeze-out

    Hadronization

    QGP

    Thermaliztion

    Hard Scattering

    Au

    Au

    Space-time Evolution of Collisions

    f

    time

    g

    e

     Expansion 

    space

    Axel Drees


    J suppression in qgp
    J/ Suppression in QGP

    • Hard scattering creates also heavy “charm” quark pairs cc

      • Small fraction of charm pairs bind to J/

    • Traveling through QGP

      c and c are screened by “color” charges

      • J/ states destroyed

    • In experiment measure J/  

      • Suppression of J/ in Pb-Pb observed at CERN

      • First data from RHIC, results coming soon

    ?

    Axel Drees


    Jets new penetrating probe at rhic

    schematic view of jet production

    jet production in quark matter

    jet production in quark matter

    hadrons

    hadrons

    hadrons

    leading

    particle

    leading

    particle

    leading

    particle

    q

    q

    q

    q

    q

    q

    hadrons

    hadrons

    leading

    particle

    leading particle

    Positron Emission Tomography of the Brain

    Jets: New Penetrating Probe at RHIC

    • jets contribute ~30% of particle production at RHIC energies

    • hard to observe directly in A-A collisions

    • indirect measurements through

      • high pT leading particles

      • azimuthal correlation

    • in colored “quark matter” partons expected to lose significant energy via gluon bremsstrahlung

      • suppression of high pT particles “jet quenching”

      • suppression of angular correlation

      • pT dependent modification of particle ratios

    jet tomography of quark matter

    Axel Drees


    PHENIX

    RHIC result on the suppression of high transverse momentum particles in high-energy gold-gold collisions is featured on the cover of next week’sPhysical Review Letters (14 January 2002)

    and in the 12/21/01 Physics Focus article on the web:

    http://focus.aps.org/v8/st34.html

    Brookhaven Science AssociatesU.S. Department of Energy

    Axel Drees


    New au au data taken in 2001

    q

    q

    Near angle

    leading

    particle

    Back angle

    New Au-Au data taken in 2001

    • Compare the yield per trigger for f ~0 and f ~p

      • (Au+Au – flow) / p+p per trigger.

      • Near angle ~ 1, pT>4 GeV/c dominantly from jet.

      • Back angle decrease with centrality Disappearance of away side jet.

    Now (2003) taking data with d-Au and p-p

    to complete picture

    Axel Drees


    Frontiers of nuclear physics
    Frontiers of Nuclear Physics

    • Extremes of Nuclear structure

      • Super heavy elements

      • High spin state nuclei

    • Radio active beams

      • Nuclei far from stability

    • Hadron structure

      • Spin structure of proton

      • Confinement

      • Hadron masses

    • Quark Gluon Plasma

      • Study phase diagram of QCD

    future

    RIA

    Nuclear Structure Lab

    ongoing

    RHIC

    Future

    upgrades

    e RHIC

    Axel Drees


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