Hadron Physics with polarized photons at 9 GeV with GlueX Richard Jones University of Connecticut UConn Physics Graduate Studies Open House, Mar. 19, 2010

2 Future

3 Motivation: the hadron mass spectrum in QCD Consider QCD with only heavy quarks: the light mesons are glueballs qq mesons have the conventional positronium low-energy spectrum spectrum is distorted at higher excitations by a linear potential for r > 0.5 fm a tube of gluonic flux forms between q and q r (fm) V 0 (QQ) (GeV) glueball decay threshold Data from Lattice QCD show :

4 gluonic excitations give rise to new potential surfaces for r >> r 0 gluonic excitations behave like flux tube oscillations flux tube model inspires the flux tube model Motivation: the hadron mass spectrum in QCD Consider QCD with only heavy quarks:

5 Motivation: conventional vs hybrid mesons m=0 CP=(-1) S+1 m=1 CP=(-1) S Flux-tube Model ground-state flux-tube m=0 excited flux-tube m=1 CP = (-1) L+S (-1) L+1 = (-1) S+1 S=0, L=0 J=1 CP=+ J PC =1 ++,1 -- (not exotic) S=1, L=0 J=1 CP= J PC = 0 -+, , , 2 +-exotic normal mesons or 1 +-

6 Recent results with unquenched lattices preliminary results Dudek et.al., preliminary pion mass 700 MeV/c 2

7 CHL-2 Upgrade magnets and power supplies 12 GeV CEBAF Upgrade

8 Construction of Hall D is underway Current plans call for the first beam in HallD/GlueX in late Ground breaking in April 2009 Live webcam feed of Hall D site

9 Gluex – discovery at the forefront of nuclear science