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Recent results from the E852 data analysis
• Motivation, E852 vs GlueX
• PWA basics
• 00 production
• and ’ spectra : have we seen exotics yet ?
• Computational challenge
• Outlook
‘Simplest’ QCD states
Lab for fundamental symmetry tests
Heavy QQ are non-relativistic
Light meson are chiral eigenstates
Beyond the quark model : glueballs, exotics
Bridge between QCD and the S-matrix theory
Why mesons ?
LS
S
1
2
S = S + S1 2
J = L + S
C = (-1)L + S
P = (-1)L + 1
JPC = 0--,0+-,1-+,2+-,
DSBquark model
Meson spectroscopy : open issues
over O(100) light mesons listed in the PDG ~ O(10) in the summary tables ~ O(1) properly described
S = (p + pp)2
t=(p’N – pp)2
M2x = (pa + pb)2 a
b
N’p
,
t/s << 1
Kinematics of peripheral production
s . 20 GeV2 , E, LAB =8-9 GeV
t < 1 GeV2 Mx . 2.5 GeV
s » 40 GeV2 , E, LAB =18 GeV
t < 1 GeV2 Mx . 3 GeV
E852 GlueX
You do it in all possible way to study systematics
0 physics input“maximal’ ambiguity
some physics input “moderate” ambiguities
… the less you know the more ambiguous the answer …
know everything no ambiguities
Dynamics of peripheral production I
a
b
c
d
t=sac
s=sab
s/t ! 1T(s,t)
(t)(t) s(t)
a c
b d
L = Re(t) Resonance (or bound state Im=0)
(18GeV) p a2 p 0 n
dN/dt
p n
-a2
t
s
Natural exchange ()
Unnatural exchange (b1)
Quasi-two body reactions
E852
II Multiple particle production - p ! 00 n
-
p
0
0
n_
s
s1
M
t1
t
s/t,s/t1,s/M2! 1
Regge + particle 4 point function
t,
- 0
0
1 ~FESR~
M2 ~ sM2<<s
00 spectrum
f2(1270)
(400-1200)
(J. Gunter et al.) 2001 - p ! 0 n
Combined analysis of CERN-Krakow-Munich and E852 data L.Lesniak at al.
badgood
=
O(p2/f2
)
+
Low order expansion
Higher order expansion
+ unitarization
Interplay between “elementary” (CDD) and “dynamical” resonances
(S=I=0)
only(no KK, no resonances)
+KK
2 Resonaces @ ~1.3, 1.5 GeV
Relevant partial waves :
S D0 D- Po P- (unnatural)
D+ P+ (natural)
Mass dependence
t-dependence
“Global features” of the ’ production
- p ! 0 n
a0 and a2 resonances
(A.Dzierba et al.) 2003 (M.Swat, Ph.D thesis) 2003
a2 1320
0 vs -
C is a good quantum number
ao and a2 are produced (helps with ambiguities)
o
ao 980
a2 1320
Work in progress on full - sample O(100K) events !
a0(980) not seen before exchange
very low t<0.1 GeV2
P-wave results from the 0 data
1(900 – 5GeV) emerges
Intensity in the weak P-waves is strongly affected by the a2(1320), strong wave due to acceptance corrections
No consistent B-W description of the P-wave fund when all helicity amplitudes where taken into account
1 BW resonance in P+
a2(1320)
2 BW resonances in D+
a2(1800) = ?
E852 ’ analysis
… combine Regge description with chiral constraints
s>>t,M
tRegge
Chiral
M
What is the origin of the P-wave in the , ’
rescattering (dual) to diffraction vs quasi-two body(resonance)
- p ! - pResults of coupled channel analysis of - p ! ’- p
D
S P
D
P
P-wave comes entirely from background : no resonances needed
- : 1(1400) > 350 MeV
’- : 1(1600) > 350 MeV
0 : 1(1400) > 350 MeV
Can be explained in terms of - ’ rescattering Constrained by the standard SU(3)L£ SUR(3) £ UA(1) effective lagrangian
: 1(1600), < 200 MeV Currently is being reanalyzed Using 150M (full) event sample (compared to 250K)
1-+ exotic : current status
An Exotic Signal in 3
LeakageFrom
Non-exotic Wavedue to imperfectly
understood acceptance
ExoticSignal
1
Correlation ofPhase
&Intensity
M( ) GeV / c2
BNL (E852) ca 1985
- p ! -+- p
CERN ca. 1970E852 2003Full sample
Software/Hardware from past century is obsolete
BNL
Compare statistics and shapes
28
4
Eve
nts
/50
MeV
/c2
SLAC
SLAC
1.0 2.52.01.5
M(3) GeV / c2
p vs p data
a2
a1
?
Condo’93 p -> + -+ n @ 19.3 GeV Adams ’93 (E852) p -> + -+ p @ 18 GeV
OPE
Photo production enhances exotic mesons
--> (JPC=1--) --> 1(JPC=1-+)
“pluck” the string (S=1,LQQ=0->Lg=1)
1-+ exotic : S=1, L=1
VMD
Condo’93
p -> X+ n
5 GeV
8 GeV
p -> X0 n
18GeV
a2
1
a2
1
1
a2
~ 50% - 100%
10%
In photoproduction
M.Swat, AS
Computational challenge
Step 1 - Reconstruction and Monte Carlo
Reconstruction and
Kinematic Fitting
M.C. data (150M)
MoreFilters
50M 25M
Data (78M) 16M 9M
This involves several hours of M.C.generation and staging of about 1TB of
data to disk and processing Time required: about a weekPerhaps re-done 2 or 3 times
Multiplepasses to
understandcuts
- p ! -+- p
This is the inputto the fitter.
Each time a changeis made to the modelthe inputs must beregenerated
25M
9M
150M
For each eventcompute massesand angles andall invariants and waves thatdepend on massesand angles
Typical # ofamplitudes: 40 or so
240 GB
40 GB
15 GB
Current model
- p ! -+- p
-
p
resonance region
a2,a1,2
,f2,f0,+
-
-
n
Step 2 - Preparing Data and Fits
with the existing software design this can take up to 1 week ! on 100 processors (40 x 80 x 10 = 32000 files)
This is being redesignedin current version this step takes< 1h !
Modern amplitude analysis
AVIDD cluster (Analysis and Visualization of Instrument-Driven Data)
2x208 2.4 GHz Pentium(IUB + IUPUI)
MANTRID
Original E852rp exotic based on0.5M eventsNow processing 10M
36-processor cluster with 1.6Tb of storage
Preliminary results from full E852 sample
a2(1320)2(1670)
Chew’s zero ?
Interference between elementary particle (2) Or the CDD pole with the unitarity cut
Inelastic diffraction : is (1800) a hybrid ?
d/dt = Ae10t
Why Hall D can resolve issues in meson spectrum
• Several orders of magnitude increase in statistics
• “Unlimited” computational resources
• New developments in theory, LGT, EFT
• High energy, intensity, polarized photon beams
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