Frontiers of Nuclear Physics A Personal Outlook

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Frontiers of Nuclear Physics A Personal Outlook

• Huan Zhong Huang
• Department of Physics and Astronomy
• University of California, Los Angeles
• Department of Engineering Physics
• Tsinghua University

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With the right tools Nuclear Physics is poised to
make significant discoveries that will also
impact other fields

• Nuclear Physics is the study of
• Nucleons and atomic nuclei as complex, many body
  system of quarks or neutrons and protons
• Bound together by fundamental forces (Quantum
  Chromo-Dynamics (QCD), nucleon-nucleon force
  (NN))
• Deep connection with evolution of the universe -
  production of the chemical elements stars,
  supernovae, etc.

Rare Isotope Accelerator (RIA)
? CEBAF 12 GeV Upgrade
? RHIC upgrade (RHIC II) ?
RIA
CEBAF

electrons
RHIC
protons
Tests of Standard Model Underground
Experiments Cold Neutron Experiments
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Topics

• RHIC Upgrade
• JLab 12 GeV Upgrade
• Rare Isotope Accelerator
• Underground Laboratory
• Electron-Ion Collider

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Relativistic Heavy Ion Collider --- RHIC
AuAu 200 GeV N-N CM energy Polarized pp up to
500 GeV CM energy
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Quark-Hadron Phase Transition
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Hadronization of Bulk Partonic Matter
1) At the moment of hadronization in
nucleus-nucleus collisions at RHIC the
dominant degrees of freedom is related to
number of constituent quarks. 2) These
constituent quarks exhibit an angular
anisotropy resulting from collective
interactions. 3) Hadrons seem to be formed from
coalescence or recombination of the
constituent quarks, and the hadron
properties are determined by the sum of
constituent quarks.
Deconfined Quark Degree of Freedom
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Constituent Quark Scaling
Baryon
Meson
Constituent (n) Quark Scaling -- Meson n2 and
Baryon n3 grouping Saturation of v2 at
Intermediate pT
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Partonic v2 and Surface Emission
At hadron formation time there is a collective
v2 among constituent quarks Recombination/coale
scence provides a hadronization scheme
(not necessarily related to partonic matter,
works for dAu) Possible geometrical nature
of v2 saturation surface emission
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Conditions at Tc
Empirically, Partonic matter evolves such that
at the hadronization, the dominant degrees of
freedom are in constituent quarks/quasi-hadro
ns. The formation mechanism could be
coalescence or recombination of these quarks.
Gluon degrees of freedom are not manifested
at hadronization, though at initial stage of
the heavy ion collision, gluons must dominate.
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Lattice QCD
LQCD, Spectral functions of hadrons (J/psi and
light hadrons) survive near TC or somewhat
above TC. Strong correlations persist up to
high temperature above TC!
LQCD e.g. S. Datta et al, hep-lat/0412037 J/y
and hC may survive up to 2.25 TC !
Our data indicate that at TTC even light
hadrons are in quasi-hadron state
(strongly interacting constituent quark
state) !
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Phase Transition ?

• The Initial State from the Collision must be
  dominated
• by gluons (Temperature?) ?Parton Evolutions (?)
• At the Hadronization Stage the dominate degrees
  of
• freedom are constituent quarks (or
  quasi-hadrons)
• (Empirical LQCD)
• What is the parton evolution dynamics??
• Empirically the dense matter with collective
  motions of
• constituent quark degrees of freedom must be
• preceded with a deconfined partonic matter,
  BUT
• we do not have any experimental indication
  that this
• is a phase transition !

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Formation of P and CP-violating Bubbles
Chiral Magnetic Effect Kharzeev et
al hep-ph/0711.0950v1
Formation of bubble with topological winding
number Qw -- separation of charge in space
-- CP Odd
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RHIC Physics in Years

• Heavy Quark Production
• -- Yield and pT distribution (Energy Loss)
• -- Parton Collectivity (Elliptic Flow)
• 2) Thermal Photon Radiation
• 3) QCD Photons (gamma-jet and QGP Brem.)
• 4) Chiral Symmetry and low mass di-leptons
• 5) Exotic Particle Searches
• 6) Search for QCD Critical Point Low Energy Scan

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RHIC Exotic Particle Factory
STAR Exciting Physics Program A full TOF
and Heavy Flavor Tracker upgrade will greatly
enhance STARs capability !!
Heavy Flavor Tracker Using Active Pixel Sensor
two layers of thin silicon detector 1.5 cm
and 4 cm radius Charmed Exotics?!
Full Barrel TOF Using MRPC
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Hadron Blind Detector
Preamps
CsI-doped Triple GEMs
Gas Box for CF4
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Silicon Vertex Tracker (VTX)
1.2lthlt2.4
hlt1.2
Pixel barrel m x 425 mm) Strip barrels(80 mm x 3
cm) Endcap Pads
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RHIC Beyond 5 Years
Hadrons with internal structure beyond
existing QCD qqq and q-qbar framework !!
RHIC Dedicated QCD Machine Beyond
Exotic
(Deconfinement Phase Transition)
AA
AA
pp
pA
pp
pA
(CGC,EMC)
(spin)
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Jefferson Lab (JLab)
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Structure of the Nucleon

• Nucleon anomalous magnetic moment (Stern, Nobel
  Prize 1943)
• Electromagnetic form factor from electron
  scattering (Hofstadter, Nobel Prize 1961)
• Deep-in-elastic scattering, quark underlying
  structure of the nucleon
• (Freedman, Kendell, Feldman, Nobel Prize 1990)

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JLab 12 GeV Upgrade
Scientific Goals 1) Quark structure of the
proton 2) Gluons in the proton 3) Nature
of Confinement 4) Exotic Particles
proton
Glueball
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Neutrino Physics
2002 Nobel Prize to Ray Davis and Masatoshi
Koshiba for detection of cosmic
neutrinos Recent experimental results from
solar, atmospheric and reactor neutrinos
confirmed 1) neutrinos must have masses 2)
neutrinos mix -- ne nm nt are not the mass
eigenstates mass eigenstates n1 n2 n3
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Neutrino Physics Program
Critical Questions for Future Neutrino Physics
Program 1) Are neutrinos their own
anti-particles? Dirac or Majorana
neutrinos 2) What are the scale of neutrino
masses and the hierarchy of the neutrino mass
ordering? 3) What is the remaining neutrino
mixing angle q13? 4) Do neutrinos violate the
CP symmetry and contribute to the
matter-antimatter asymmetry?
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Double Beta Decay
2???
2nbb T1/2 1018y
1935
M. Goeppert-Mayer
(A,Z) ? (A,Z2) 2e 2?ne
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Dirac or Majorana Neutrinos?
0???
1937
Majorana ? neutrino anti-neutrino Lepton Number
violation !
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Neutrino Masses and Hierarchy
Normal
Inverted
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Neutrino Mixing Angles
Pontecorvo-Maki-Nakagawa-Sakata Matrix
Parametrize the PMNS matrix as
Solar, reactor
reactor and accelerator
0???
Atmospheric, accelerator
?23 45
?13 ?
?12 32
d CP violation in lepton sector ?! Need to
determine q13 with precision !
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Underground Laboratory
Physics Topics 1) Solar Neutrino/Atmosphere
Neutrino 2) Double beta Decay 3) Dark
Matter
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eRHIC as an electron-ion collider
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eRHIC Inevitable ?! But When?
RHIC II Machine Upgrade -- Tandem -- Electron
Cooling
Electron LINAC 10 GeV
Natural Physics Direction from RHIC/JLAB 20
Years ?
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The End
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Solar Neutrino Energy Spectrum
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Two Generation Model
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combined analysis SNO and KamLand
Best fit Dm27.1 x 10-5eV2 tan2q 0.41