Photons and Dileptons
35
Photons and Dileptons K. Dusling (NC) and I. Zahed BNL 11
description
Photons and Dileptons. K. Dusling (NC) and I. Zahed. BNL 11. Outline. Set up Rates Evolution Experiments. AA Cartoon. time. Formally . acceptance. evolution. rate. Acceptance: NA60 vs PHENIX. Hadronic Rates. Rate. l +. l +. l -. l -. π. π. π. π. N. N. - PowerPoint PPT Presentation
Transcript of Photons and Dileptons
Photons and Dileptons
K. Dusling (NC) and I. Zahed
BNL 11
Outline
• Set up• Rates• Evolution• Experiments
AA Cartoon
time
Formally
rateevolution
acceptance
Acceptance: NA60 vs PHENIX
Hadronic Rates
Rate
)0(),()()(
41
21
604
2
2
2
2
23
2
4
JxJxexdqWqm
qm
qqddR xiqll
)0()()( with )(Im1
2),( *4
/
00
JxJTexdiqWqW
eqqW xiqFF
Tq
l+
l-
l+
l-π
π
N
π
π
N
Hadronic Expansion
i d4 x e iqx 0T*J (x)J(0)0 i
a d d4 x e iqx in
a (k)T*J (x)J(0) ina (k)
is,I dN d 4 x e iqx N in
s,I (k)T*J (x)J(0) N ins,I (k)
+2+3, …-Pi, +2+3, …-K
Resonance Gas: 0 ie J=ρ,ρ’,ρ’’,..
+2+3, …-N
Many Feyman Graphs:
l l
l l
,,
i d4 x e iqx 0T*J (x)J(0)0 + + …
l
l
,,,, 11 Ka
ia d d4 x e iqx in
a (k)T*J (x)J(0) ina (k) + …
ll
NN
,
,N ,N
is,I dN d4 x e iqx N in
s,I (k)T*J (x)J(0) N ins,I (k) + …
Chiral Ward Identities: κ
d3k n(k0)(2 3)2k0 f
2 W1F (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 in
a (k)T*J (x)J (0) ina (k)
Chiral Limit and zero-mtm pion:
)()(Im12)0,( 2221 qqqqW AV
F
κ
VA Mixing=LxR Restoration?
Dey, Eletsky, Ioffe 96
~κ
Expansion Parameter:
n
2m f2
n 3 d3k(2 )3 n(k )
= 0
0
“Dilute”
LXR
Chiral Ward Identities: κ^2
Input:
V (q2) 0 TVV 0
A (q2) 0 T jAjA 0
e+e- Decay
.
VA Mixing in
T=180 MeV
Typical Mixing in
a1a1
T=150 MeV μb=225 MeV
VA Mixing + Bremsstralung
QGP Rates
wQGP:
ImW11R
14
NC eq2
q
q
2 12Tq
ln n
n
l+
l-
l+
l-
wQGP: γ
Collinear Enhancement+ LPM Effect : Arnold, Moore, Yaffe 01
Hydro Evolution
Fireball: NA60
TC 160 MeVs /nB 42Tf ,o. 120 MeV
LH = 6 GeV/fm-3
Thermal Freeze-out
Cooper-Frye
Chemical Freezeout:
Fireball cools faster x Rates higher = w/μπ !
Experiments
NA60:
PHENIX:
Dusling+Z 07 Dusling+Z 09
28
STAR: 11’
PHENIX PRC 81 (2010) 034911
Minbias (value ± stat ± sys) Central (value ± stat ± sys)
STAR 1.53 ± 0.07 ± 0.41 (w/o ρ) 1.40 ± 0.06 ± 0.38 (w/ ρ)
1.72 ± 0.10 ± 0.50 (w/o ρ) 1.54 ± 0.09 ± 0.45 (w/ ρ)
PHENIX 4.7 ± 0.4 ± 1.5 7.6 ± 0.5 ± 1.3Difference 2.0 σ 4.2 σ
Enhancement factor in 0.15<Mee<0.75 Gev/c2
Note: Acceptance difference etc.
WA98: γ
0<qT (GeV) <4 0<qT (GeV)<0.8
N:x2
Rates at RHIC: γ
RHIC1 RHIC2
PHENIX: γ
RHIC1 RHIC2
PHENIX extrapolation: γ
PHENIX: M<<qv
1
Systematics of the Extrapolation
15% Systematics!
LHC: γ
0<qT(GeV)<2 1<qT (GeV)<5
Achievements
1. EM “OK”*2. LxR “restored”3. QGP “visible”
(* PHENIX)
