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Status of Exotic Meson Searches. Spin exotics and glueballs essential to our understanding of QCD. Limit comments to new results or new experiments. WA102, Crystal Barrel, E852, CLAS, GlueX, Compass. Lattice QCD mass predictions. Scalar glueball at about 1.6 GeV. Tensor at 2.3 GeV. - PowerPoint PPT Presentation
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Status of Exotic Meson Searches
• Spin exotics and glueballs essential to our understanding of QCD.
• Limit comments to new results or new experiments.– WA102, Crystal Barrel, E852, CLAS,
GlueX, Compass
Lattice QCD mass predictions
• Scalar glueball at about 1.6 GeV.– Tensor at 2.3 GeV.
• Hybrid spin-exotics start at about 1.9 GeV (Jpc=1-+).
• Reviewed by McNeile, hep-lat/0207001 (2002)
Glueball searches - 4 decay
• CERN WA102 (central production)• pp4pp PWA
– f0(1370); dominant
– f0(1500); and
– f0(2000); dominant• Barberis et al., PL B471, • 440 (2000) M4
Glueball searches - 4 decay
• CRYSTAL BARREL• • important disagreement with
WA102• Abele, et al., Eur. Phys. J. C21, 261
(2001).
Xnp
•Future: , ’
Hybrid searches
• BNL E852• pMp
– previous: 1(1400), 1(1600)
– recent: 1(1600)’-
• Ivanov, et al., PRL 86, 3977 (2001)
E852 partial wave fits
• 1(1600)’- dominant!
• M=1.60 GeV, =0.34 GeV• Future:
• b1
• f1
• K1K
• K*K•
a2
E852 - preliminary
• 0PWA
• large b1 width for 1
– hybrid meson?
1-+ b1 Sintensity
4++ D
1-4
1.6 2.0 2.4 M (GeV)
New experiments
• Jefferson Lab. CLAS• pMp with M3
– tagged E 5.2 GeV
Motivation:
“vector meson” probe.
Good acceptance for few-body decays.
CLAS preliminary
• Large production rates• Search:
– isovector 1-+, 3-+
– isoscalar 2+-, 4+-
– SLAC 1.8 GeV bump• Condo, et al., PRD 43, • 2787 (1991)
400k events
0.8 1.2 1.6 2.0
a2
M3
JLAB GlueX proposal
• New facility - big part of lab upgrade
• polarized high-flux beam (E= 9 GeV)
• dedicated spectrometer
CERN COMPASS
• Meson program: – pp central production– Primakoff by A interactions– P diffraction
• L. Schmitt, Proceedings of XXXVII Int. Winter Meeting on Nucl. Phys., Bornio, 1999
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