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Jan. 19, 2005GlueX/Exotics 2005 GlueX: Search for Gluonic Excitations at JLab Dr. David Lawrence Jefferson Lab Dr. David Lawrence Jefferson Lab.

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Presentation on theme: "Jan. 19, 2005GlueX/Exotics 2005 GlueX: Search for Gluonic Excitations at JLab Dr. David Lawrence Jefferson Lab Dr. David Lawrence Jefferson Lab."— Presentation transcript:

1 Jan. 19, 2005GlueX/Exotics 2005 GlueX: Search for Gluonic Excitations at JLab Dr. David Lawrence Jefferson Lab Dr. David Lawrence Jefferson Lab

2 Jan. 19, 2005GlueX/Exotics 2005 Motivation Simplest quark-structure is a meson Confinement: Quarks cannot exist alone Meson Wave Function

3 Jan. 19, 2005GlueX/Exotics 2005 Hybrid Models Bag Model Flux Tube Model Constituent Gluon Model QCD Sum Rules + Lattice Gauge Theory ( model indep.)

4 Jan. 19, 2005GlueX/Exotics 2005 The Flux Tube Model G. Bali

5 Jan. 19, 2005GlueX/Exotics 2005 Hybrid Mesons ~1GeV mass difference

6 Jan. 19, 2005GlueX/Exotics 2005 Hybrid Mesons += L = 1 J PC = 1 -+, 1 +- S = 0 L = 0 J PC = 0 -+ (, K ) J PC = 1 --, 1 ++ Hybrid Meson or,,, … ? P = (-1) L+1 C = (-1) L+S

7 Jan. 19, 2005GlueX/Exotics 2005 Hybrid Mesons += L = 1 J PC = 1 -+, 1 +- S = 1 L = 0 J PC = 1 -- (, ) J PC = 0 -+, 1 -+, , 1 +-, 2 +- Exotic!

8 Jan. 19, 2005GlueX/Exotics 2005 Hybrids Should Appear as a Nonet 9 hybrid particles Should exist for each J PC combination

9 Jan. 19, 2005GlueX/Exotics Hybrid Mass spectrum From LQCD calculations. All masses in GeV/c 2 UKQCD(97) Collaboration / MILC(97) MILC(99) (sys) SESAM(98) Mei & Luo(03) Bernard et al.(04)

10 Jan. 19, 2005GlueX/Exotics 2005 Exotic quantum numbers imply deeper structure than simple (No mixing with those states!) Light Meson Spectrum

11 Jan. 19, 2005GlueX/Exotics 2005 Why Are Hybrids Hard To See? Most searches involve looking at two body final states. Coupling of hybrids to two body final states is almost nonexistent Large masses (~2GeV/c 2 ) About 1/3 of the (exotic) states have broad widths

12 Jan. 19, 2005GlueX/Exotics 2005 Hybrid Decays X a 2 X a 1 X f 1 X b 1 Hybrids preferentially couple to states with Both an S-wave and P-wave meson

13 Jan. 19, 2005GlueX/Exotics 2005 Hybrid Candidates(?) 1 (1400)1 -+ E852,Crys. Barrel,VES 1 (1600)1 -+ E852,Crys. Barrel,VES 1 (2000)1 -+ E852 2 (1880)2 -+ E852 a 1 (2096)1 ++ E852

14 Jan. 19, 2005GlueX/Exotics (1400) J PC = 1 -+ Decay modes not hybrid-like (Looks like a meson-meson molecule!)

15 Jan. 19, 2005GlueX/Exotics (1600) J PC = 1 -+ E852 PRL 86, 3977 (2001)

16 Jan. 19, 2005GlueX/Exotics (2000) J PC = 1 -+ E852 hep-ex/ v1 (2004) ; E852 Phys. Lett. B595(2004) f 1 (1285)

17 Jan. 19, 2005GlueX/Exotics 2005 Hadroproduction vs. Photoproduction,K Non-Exotic Exotic*

18 Jan. 19, 2005GlueX/Exotics 2005 Incident Photon Energy Need at least E = 8.4GeV - 9GeV to access masses up to 2.8GeV/c 2

19 Jan. 19, 2005GlueX/Exotics 2005 Having the angle between the photon polarization vector and reaction plane provides an additional handle in the analysis that can simplify the PWA. Linearly Polarized s (produced by coherent bremsstrahlung) The angle is related to naturality of exchange particle e.

20 Jan. 19, 2005GlueX/Exotics 2005 Location of Jefferson Lab

21 Jan. 19, 2005GlueX/Exotics 2005 Jlab Upgrade Enhance equipment in existing halls CHL-2 Upgrade magnets and power supplies add Hall D (and beam line)

22 Jan. 19, 2005GlueX/Exotics 2005 The GlueX Detector 1 Hermetic Design

23 Jan. 19, 2005GlueX/Exotics 2005 The GlueX Detector (all aboard!)

24 Jan. 19, 2005GlueX/Exotics 2005 Acceptance of GlueX detector p 1 p + 4 p cos GJ GJ Good acceptance of both charged and neutral particles

25 Jan. 19, 2005GlueX/Exotics 2005 PWA Double Blind Monte Carlo Study of 3 Final states p n X p 1 + n + + n n Background waves included a 1 (1260), a 2 (1320) and 2 (1670)

26 Jan. 19, 2005GlueX/Exotics 2005 Protoyping and Testing

27 Jan. 19, 2005GlueX/Exotics 2005 Beam Flux and Event Rate E electron = 12GeV Coherent Peak E = 9GeV R 10 7 /s10 8 /s Hadronic Rate 37kHz (total) 1.4kHz (tagged) 370kHz (total) 14kHz (tagged) Trigger Rate 20kHz200kHz Data rate 100 MB/s1GB/s In the first year, GlueX will exceed existing photoproduction data by a couple of orders of magnitude. It will also exceed existing hadroproduction data.

28 Jan. 19, 2005GlueX/Exotics 2005 Status of Upgrade CD-0Approve Mission Need CD-1Approve Preliminary Baseline Range CD-2Approve Performance Baseline Range CD-3Approve Start of Construction Start of Data Taking FY2004 FY2005 FY2007 FY2008 FY2011 DOE Order Project Management Manual

29 Jan. 19, 2005GlueX/Exotics 2005 Summary Understanding confinement means understanding the glue which binds quarks. Hybrid mesons are perhaps the most promising subject for studying the nature of the glue A rich spectrum of hybrid mesons is predicted. Models agree the masses of hybrid states should be around 2GeV, some with exotic J PC.

30 Jan. 19, 2005GlueX/Exotics 2005 Summary GlueX is being constructed to map out the spectrum of Exotic Hybrid Mesons with unprecedented statistics. GlueX will begin taking data in 2011


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