Neda Sadooghi
Sharif University of Technology
Tehran-Iran
Munich-January 2011
1
Strong nuclear force
Force
Electromagnetic force
Strength
Theory
Mediator
Strong
1of Everything
Chromodynamics
Gluon
Theory
Electromagnetic
10-2
Electrodynamics
Photon
Weak
10-7
Flavordynamics
W+, W-, Z0
Gravitational
10-39
Geometrodynamics
Graviton
Weak nuclear force
Gravitational force
2
1019 GeV
1014 GeV
100 GeV
Inflationary
Epoch
Big Bang
100 MeV
~10-4 eV
QCD Phase
Transition
QGP
EW Phase
Transition
3
Interaction
Couples to
Gauge Bosons
Mass (GeV/c2)
Strong
Color charge
Gluon
0
Electromagnetic
Electric charge
Photon
0
Weak
Weak charge
W+, W-, Z0
~100
SU(3) x SU(2) x U(1)
Fermions
Leptons
Quarks
Family
E- Charge
1
2
3
νe
νμ
ντ
0
e
μ
τ
-1
u
c
t
+2/3
d
s
b
-1/3
Quark flavors
Color
-
Weak
Isospin
LH
RH
1/2
-
Spin
1/2
0
r g b
1/2
0
1/2
0
Quark colors
4
Quantum Electrodynamics (QED) describes the force
between electrically charged particles in terms of
exchange of massless and neutral photons
Elementary process (three point vertex):
5
Quantum Electrodynamics (QED)
Coulomb
Repulsion
Coulomb
Attraction
6
Quantum Chromodynamics (QCD)
Elementary process(es)
Gluons carry color-charge
Gluon-Gluon
Self-Interaction
7
Flux Lines
Electric flux between a pair of Chromoelectric flux between
equal and opposite charges
 Dipole field pattern
a quark and an antiquark
 Flux tube
8
Quantum Chromodynamics (QCD)
Static potential between a quark-antiquark pair
A(r )
V (r )  
 r
r
A(r )  
1
ln r
r 0 ↷ A(r) 0 ↷ V(r) 0
Asymptotic Freedom
 ~ 880 MeV / fm
9
String Tension
σ~ 880 MeV/fm
A force sufficient to lift three elephants
!!!
10
Confining
Potential
Color Confinement
Hadrons are color singlet
11

Helicity:

For massless particles, helicity and chirality are the same

Right handed particles have positive helicity (chirality)

Left handed particles have negative helicity (chirality)

Up and down quarks can be regarded as massless  A theory
including only up and down quarks should be symmetric
under global chiral transformation
12
13
The mysteries of Mexican Hat Potential
Spontaneous Chiral Symmetry Breaking:
(Pseudo) Goldstone Mechanism: SUL(2) x SUR(2)  SUL+R(2)
π+
π0
π-
100 MeV
QCD Phase
Transition
Big Bang
QGP
15
QCD phase transition at TQCD~2.4 x1012 K~ 200 MeV
Core of our Sun ~ 1.57 x 107 K ~1.3 keV
Room temperature ~ 27 C ~ 300 K ~ 25 meV
16
N
d
d
u
LHC
s
RHIC
Early Universe
Temperature
QCD Phase Diagram
u
ConfinementChiral
Deconfinement
Symmetry
phase
Restoration
Hadronic Fluid
transition
u
u
Hadronic Phase
Hadron gas
s
s
s
Quark Gluon Plasma Phase
SPS
Tc~170 MeV
d
Nuclear Matter
μc~310 MeV
d
d
s
d
u
u
s
s
d
u
u
CFL
2SC
s
Color
phase
d Superconducting
Neutron Stars
Baryonic Chemical Potential
17
Neutron stars:
Laboratories of Matter under
Extreme Conditions
18
Natural laboratory for extreme conditions

Neutron star is a type of stellar remnant that can result
from gravitational collapse of a massive star during a
supernova event

When a giant star dies, it can collapse into a black hole
or implode into an ultra-dense neutron star

Pauli exclusion principle supports the neutron star
against further collapse (they are made almost entirely
of neutrons)
19
Neutron star radius: 12 km
0.3-0.4 ϱ0
0.5-2.0 ϱ0
>2ϱ0
Outer crust 0.3-0.5 km
Ions and electrons
Inner crust 1-2 km
Electrons, neutrons, nuclei
Outer core ~9 km
Neutron-proton Fermi liquid
Few % electron Fermi gas
Inner core 0.3 km
Quark-Gluon Plasma/
CFL Color Superconductor
???
20
Radius
6.4x103 km
~6.96 x105 km
12 km
108 x Earth
Mass
6x1024 kg
2x1030 kg
~3x106 x Earth
2.4x 1030 kg
1.2-2 Solar mass
Density
5 g/cm3
(Mean density)
162.2 g/cm3
(Core)
2.7 x1014 g/cm3
(Core)
Surface gravity
g
~28 g
7x1011 g
Escape velocity
11 km/s
617.7 km/s
1.3x105 km/s
56 x Earth
1/3 c
1.57 x 107 K
1011 K~ 1-10 MeV
Temperature
(Core)
5700 K
~104 Solar T
21
Neutron Stars
 5.5 10 kg  900 
12
22
Pulsars are highly magnetized, rotating
neutron stars that emit a beam of electromagnetic radiation
Because neutron stars are very dense objects,
the rotation period and thus the interval
between observed pulses is very regular 
Atomic Clocks 
The observed periods of the pulses range
from 1.4 msec to 8.5 sec
Extremely large magnetic fields  Magnetars
Surface: B~1014-1015 G
Inner field: B~1018-1020 G
23
Extreme Magnetism
The Earth’s B field
Measured at the magnetic pole
0.6 G
Hand-held magnet
Like those used to stick papers on a
refrigerator
100 G
Within dark, magnetized areas on
the solar surface
4000 G
The strongest, sustained
magnetic fields
achieved in the lab
Generated by huge electromagnets
4.5 X 105 G
~ 45 T
The strongest fields ever
detected on non-neutron
stars
Strongly-magnetized, compact
white dwarf stars
The magnetic field in
strong sunspots
Typical surface
magnetic fields of radio
pulsars
Magnetars: Inner fields
The most familiar kind of
neutron star
Soft gamma repeaters and anomalous
X-ray pulsars
108 G
1014-1015 G
1018-1020 G
24

Vacuum Birefringence (double refraction)
Polarized
lightSome
waves
change
speed
Calcite crystal:
letters
showing
the and hence
wavelength
when they enter a very strong magnetic
double refraction
field
Liquid Crystal Displays are also birefringent

Photon Splitting
X-rays split in two or merge together. This process is
important in fields stronger than 1014 G

Scattering Suppression
A light wave can glide past an electron with little
hindrance if the field is large enough to prevent the
electron from vibrating with the wave

Distortion of Atoms
Fields above 109 G squeeze electron orbitals into cigar
shapes. In a 1014 G field, a hydrogen atom become
200 times narrower
25
RHIC
LHC
N
Early Universe
Temperature
Effects of Extreme Magnetism on Quark Matter
Quark Gluon Plasma Phase
Tc~170 MeV
Hadronic Phase
Chiral-SB phase
Color Superconducting phase
Neutron Stars
Baryonic Chemical Potential
26
27

Center of mass energy
√s=200 AGeV for Au+Au collision

Collision with 99.7% speed of light  Ultra-RHIC

The energy density
ε= 5.5 GeV/fm3

The pressure generated at the time of impact
1030 atmospheric pressure
28
Question:
Deconfinement Phase Transition
29
?
?
 Color Glass Condensate (CGC) sheets
CGC
 Initial singularity at the time of collision
 Glasma phase (Out of Equilibrium Physics)

Not expected: Strongly correlated QGP (Perfect Fluid)
Initial
Singularity
Glasma
 Mixed phase (quarks, gluons and hadrons)
sQGP
 Hadron Gas
Hadron Gas
30
The evolution of matter produced in the
Little Bang is comparable with the
Big Bang (same evolution equations)
t=10-21-10-20sec
t=10-22-10-21sec
t=0-10-22sec
Perfect Liquid: Strongly Correlated QGP
Idea supported by the conjecture of AdS/CFT duality
T
Magnetized Plasma
e-strongly correlated
Tc
Electric Plasma
m- strongly correlated ??
T~ 2 Tc
Deconfinement
sQGP
Confinement
Dual superconductivity
m-correlation
e-confined
CS
(Color) Superconductivity
e-correlation
m-confined ??
1101.1120 Shifman et al
μB
32
Chiral Magnetic Effect
Parity Violation in QCD  Strong CP Problem
Question: Is the world distinguishable from its mirror image?
Answer(s):
 Weak interaction violates P and CP
 Strong interaction:
C: Matter↔Antimatter
P: Mirror symmetry
Experimentally:
Neutron’s
EDM ~No
0 evidence of global strong CP violation
Theoretically: QCD θ ≠ 0 ( topological charge)
Thebound
existence
topological
charge
 CP problem
Experimental
for of
θ<
3x10-10 
Strong
Matter-Antimatter asymmetry in the Early Universe !!
33
Chiral Magnetic Effect
Local (event by event) P and CP Violation in QCD
Theory:
Fukushima,
(2007-09)
Charge
separation
stemsKharzeev,
from theWarringa,
interpaly McLerran,
between the
strong
magnetic
field in the early stage of heavy ion collision and the
Lattice: Polikarpov et al. (2009-10)
presence of topological configurations in hot matter
→ →
B~L
Charge separation  Electric current
QGP in the deconfined phase
 
J~B
34
Chiral Magnetic Effect
Local Parity Violation in QCD  Chiral magnetic Effect



B

p
uL
dR
dR
uR
Charge Separation
 dR
J~B
L
uR
dL
R
uR
 0
35
Chiral Magnetic Effect
RHIC
√sNN ~ 200 GeV b~4 fm eB ~1.3 mπ2 ↷ B ~ 4x1018 G
Very Strong Magnetic Field
Non-Central HIC
1019 Gauss
√sNN ~ 200 GeV
LHC
Non-Central HIC
√sNN ~ 4.5 TeV
eB (MeV2)
RHIC
Non-Central HIC
b~4 fm
b~4 fm
eB ~1.3 mπ2 ↷ B~ 4x1018 G
eB ~15 mπ2 ↷ B~ 5x1019 G
1014 Gauss
D.E.of
Kharzeev,
L.D. McLerran,
H.J. Warringa
(0711.0950)
The strength
B is comparable
withand
Magnetic
Field in
Neutron Stars
36
RHIC
N
LHC
Temperature
Effect of Strong Magnetic Fields on
Color Superconductivity
Quark Gluon Plasma Phase
Tc~170 MeV
Hadronic Phase
Chiral-SB phase
Color Superconducting phase
Neutron Stars
Baryonic Chemical Potential
37
Effect of Strong Magnetic Fields on
Color Superconductivity
QED Superconductivity vs. Color Superconductivity
Ingredients:
(QED) A liquid of fermions with electric charge
(QCD) Quarks with electric and color charges
q
q
(QED) An attractive electromagnetic interaction between the fermions
(QCD) An attractive strong interaction between two quarks
(QED) Low temperature: T<Tc
(QCD) Low temperature: In neutron stars T<100 MeV ≪ Big Bang T~1019GeV
Results:
(QED) QED Meissner Effect  Photons acquire mass
(QCD) QCD Meissner Effect  Gluons acquire mass
38
Effect of Strong Magnetic Fields on
Color Superconductivity
Effects on QCD Phase Diagram (I):
Sh. Fayazbakhsh and NS: PRD (2010)
Normal
ChSB
ChSB
CSC
ChSB
CSC
Normal
CSC
Normal
Normal
ChSB
Normal
ChSB
ChSB
39
Effect of Strong Magnetic Fields on
Color Superconductivity
Effects on QCD Phase Diagram (II):
Low μ: Only chiral phase transion
De
Haas-van
oscillations
Alphen
before
the
system enters the regime
of LLL dominance
2nd order phase
transition from chiral SB
to the Normal phase
40
Effect of Strong Magnetic Fields on
Color Superconductivity
Effects on QCD Phase Diagram (III):
Low T: Chiral and Color phase transions
41
Results
1. The type of the phase transition between chiral SB and the
Normal phase changes with B: 2nd Order  1st Order
2. Increasing B has no effect on the type of phase transition
between the color symmetry breaking and the normal phase
(2nd order)
3. De Haas-Van Alphen oscillations  CSC-Normal-CSC phase
transition
5. For eB>eBt ~ 0.5 GeV2: System is in the LLL dominant regime
4. For eB>eBt: The effect of T and μ are partly compensated by B
42
43
Effect of Strong Magnetic Fields on
Color Superconductivity
Effects on QCD Phase Diagram (II):
Intermediate μ: Chiral and Color phase transions
44
Effect of Strong Magnetic Fields on
Color Superconductivity
Effects on QCD Phase Diagram (II):
Large μ: Only Color phase transion
45
Effect of Strong Magnetic Fields on
Color Superconductivity
Effects on QCD Phase Diagram (III):
Intermediate T: Chiral and Color phase transions
46
Effect of Strong Magnetic Fields on
Color Superconductivity
Effects on QCD Phase Diagram (III):
Large T: Only Chiral phase transion
47