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Dileptons and Photons at Collider Energies. K. Dusling , C.H. Lee and I . Zahed. BNL14. Outline. Motivation Rates, Evolution Experiments. Na45: 95’. Phenix : 07’. Na60:03’. Star: 13’. Formally. acceptance. evolution. rate. time. Rates: Hadrons. Equilibrium averaging. - PowerPoint PPT Presentation
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Dileptons and Photons at Collider Energies
K. Dusling, C.H. Lee and I. Zahed.
BNL14
Outline
• Motivation• Rates, • Evolution• Experiments
Na45: 95’
Na60:03’
Phenix: 07’
Star: 13’
Formally
time
evolution rate
acceptance
Rates: Hadrons
Equilibrium averaging
Hadronic Expansion
In Diagrams
i d4 x e iqx 0T*J (x)J(0)0 i
a
d d4 x e iqx ina (k)T*J (x)J(0) in
a (k)
is,I
dN d4 x e iqx N ins,I (k)T*J (x)J(0) N in
s,I (k)
1,2,3,
…-Pi,
Resonance Gas
1,2,3-N l
l
,,,, 11 Ka
ia
d d4 x e iqx ina (k)T*J (x)J(0) in
a (k) + …
ll
N
N
,
,N ,N
is,I
dN d4 x e iqx N ins,I (k)T*J (x)J(0) N in
s,I (k) + …
l l
l l
,,
i d4 x e iqx 0T*J (x)J(0)0
Vector-Axial Mixing: κ
d3k n(k0)
(2 3)2k0 f2 W1
F (q,k)
W1F 12q2 ImV (q2)
6(k q)2 ImA[(k q)2]
8((k q)2 m2q2)ImV (q2) Re[R (k q)]
(q q)
ia
d d4 x e iqx ina (k)T*J (x)J(0) in
a (k)
Chiral Limit and zero-mtm pion:
κ
Data :
V (q2) 0 TVV 0
A (q2) 0 T jAjA 0
e+e-
Decay
.
VA-Mixing explicitly
Dey, Eletsky, Ioffe 96
Vector Spectral Function
2-pion Final state:
Electric Conductivity:
Hadronic vs Lattice:
Flavour Susceptibility:
in details:
Flavour Susceptibility:
Rates
Rates: 1 Nucleon
:
=
1 Loop ChPT N- Transition
I
N
F
N smspqWe )()(4),( N
tot
22
WNF (q) i d4 x e iqx N in
s,I (k)T*J (x)J(0) N ins,I (k)
s,I
+
:*
Input at the Photon Point
N background 00 22 qq
Typical Mixing in
a1a1
T=150 MeV μb=225 MeV
Rates: sQGP
sQGP:
ImW11R
1
4NC eq
2
q
q
2 12Tq
lnn
n
l+
l-
l+
l-
ImW11R
1
4NC eq
2
q
q
2 s
A4
2 4 2
Tq
n 1 n n 1 n
Hansson and Zahed 91’
Electric Conductivity
sQGP Rates
Evolution
Sample hydro evolution
Faster cooling x higher rates: same
V2 Flow @ 2.76 TeV
Dileptons: NA60, Phenix, Star
NA60 : dN/dη=140 95’
Pt Spectra: low
Pt Spectra: High
PHENIX
Beam Energy Scan: STAR 13’
Photons: WA90, PHENIX
WA98
0<qT (GeV) <4 0<qT (GeV)<0.8
PHENIX
RHIC1 RHIC2
PHENIX extrapolation: γ
PHENIX: M<<qv
1 15% Systematics!
V2 PHENIX
Achievements
1. EM “OK”*
2. LxR “restored”
3. QGP “visible”
4. V2 “low”
(* π < < ρ)
