An Experimental Overview of Gluonic Mesons Curtis A

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An Experimental Overview of Gluonic Mesons Curtis A. Meyer Carnegie Mellon University May 14,

An Experimental Overview of Gluonic Mesons Curtis A. Meyer Carnegie Mellon University May 14, 2003 1 May 14, 2003 Curtis A. Meyer

Talk Outline What are gluonic excitations ? Hybrids and Glueballs Overview of evidence for

Talk Outline What are gluonic excitations ? Hybrids and Glueballs Overview of evidence for exotic quantum number states. Non-exotic quantum number states. Overview of Glueballs. 2 May 14, 2003 Curtis A. Meyer

Normal Mesons quark-antiquark pairs Non-quark-antiquark 0 -- 0+- 1 -+ 2+- 3 -+ …

Normal Mesons quark-antiquark pairs Non-quark-antiquark 0 -- 0+- 1 -+ 2+- 3 -+ … orbital u s d s u d J=L+S P=(-1) L+1 C=(-1) I G=C (-1) 3 May 14, 2003 L+S (2 S+1) 1 S L J =0 3 S = 1 -1 0 Curtis A. Meyer -+ 3, 3, f 3, K 3 2, 2, f 2, K 2 L=2 , , f , K 1 1 2, 2, ’ 2, K 2 3 -2 -1 -2 -+ a 2, f’ 2, K 2 a 1, f’ 1, K 1 L=1 a , f’ , K 0 0 b 1, h’ 1, K 1 2++ , , f, K* L=0 , , ’, K 1 -0 -+ 1++ 0++ 1+- radial

Spectrum qq Mesons Each box corresponds to 4 nonets (2 for L=0) Radial excitations

Spectrum qq Mesons Each box corresponds to 4 nonets (2 for L=0) Radial excitations 2 –+ 0 –+ 2 ++ Glueballs 2. 0 1. 5 2 +– 2 –+ 1 –– 1– + 1 +– 1 ++ 0 +– 0 –+ Hybrids 2. 5 0 ++ 1. 0 0++ 1. 6 Ge. V L=0 4 May 14, 2003 1 2 3 4 Curtis A. Meyer (L = qq angular momentum) exotic nonets Lattice 1 -+ 1. 9 Ge. V

Lattice QCD Flux Tubes Realized From G. Bali Color Field: Because of self interaction,

Lattice QCD Flux Tubes Realized From G. Bali Color Field: Because of self interaction, confining flux tubes form between static color charges Confinement arises from flux tubes and their excitation leads to a new spectrum of mesons 5 May 14, 2003 Curtis A. Meyer

Hybrid Mesons built on quark-model mesons ground-state flux-tube m=0 normal mesons CP={(-1)L+S}{(-1)L+1} ={(-1)S+1} Flux-tube

Hybrid Mesons built on quark-model mesons ground-state flux-tube m=0 normal mesons CP={(-1)L+S}{(-1)L+1} ={(-1)S+1} Flux-tube Model m=0 CP=(-1) S+1 m=1 CP=(-1) S 6 May 14, 2003 Curtis A. Meyer excited flux-tube m=1 1 -+ or 1+- S=0, L=0, m=1 S=1, L=0, m=1 J=1 CP=+ J=1 CP=JPC=0 -+, 0+- JPC=1++, 1 -- 1 -+, 1+- (not exotic) exotic 2 -+, 2+-

Hybrid Predictions Flux-tube model: 8 degenerate nonets 1++, 1 -- 0 -+, 0+-, 1

Hybrid Predictions Flux-tube model: 8 degenerate nonets 1++, 1 -- 0 -+, 0+-, 1 -+, 1+-, 2 -+, 2+- ~1. 9 Ge. V/c 2 S=0 S=1 Lattice calculations --- 1 -+ nonet is the lightest UKQCD (97) 1. 87 0. 20 ~2. 0 Ge. V/c 2 MILC (97) 1. 97 0. 30 -+ 1 MILC (99) 2. 11 0. 10 Splitting 0. 20 0. 50 +0 Lacock(99) 1. 90 0. 20 +2 Mei(02) 2. 01 0. 10 In the charmonium sector: 1 -+ 4. 39 0. 08 Splitting = 0. 20 +0 4. 61 0. 11 7 May 14, 2003 Curtis A. Meyer

Decays of Hybrids The angular momentum in the flux tube stays in one of

Decays of Hybrids The angular momentum in the flux tube stays in one of the daughter mesons (L=1) and (L=0) meson. L flux Lflux Exotic Quantum Number Hybrids 1 b 1 , f 1 , , a 1 1 (1300) , a 1 1: . 25: . 20 1: 1 b 2 a 1 , h 1 , , a 2 h 2 b 1 , , 1: 1: 0. 5: 0. 25 1: 1: 0. 1 b 0 (1300) , h 1 h 0 b 1 , h 1 1: 0. 20 1: 0. 02 8 May 14, 2003 Curtis A. Meyer Mass and model dependent predictions

Glueball Mass Spectrum What role do gluons play in the meson spectrum? Lattice calculations

Glueball Mass Spectrum What role do gluons play in the meson spectrum? Lattice calculations predict a spectrum of glueballs. The lightest 3 have JPC Quantum numbers of 0++ , 2++ and 0 -+. The lightest is about 1. 6 Ge. V/c 2 f 0(1710) a 0(1450) f 0(1500) K*0(1430) f 0(1370) Morningstar et al. a 0(980) 9 f 0(980) May 14, 2003 Curtis A. Meyer

Glue-rich channels G M Radiative J/ Decays 0 -+ (1440) M ++ 0 f

Glue-rich channels G M Radiative J/ Decays 0 -+ (1440) M ++ 0 f 0(1710) Large signals Proton-Antiproton Annihilation 0++ f 0(1370), f 0(1500) Central Production (double-pomeron exchange) 0++ f 0(1370), f 0(1500), f 0(1710) Glueballs should decay in a flavor-blind fashion. 10 May 14, 2003 Curtis A. Meyer

E 852 Results Exotic Quantum Numbers 1 -+ in Mass = 1370 +-16+50 -30

E 852 Results Exotic Quantum Numbers 1 -+ in Mass = 1370 +-16+50 -30 Me. V/c 2 1(1400) Width= 385 +- 40+65 2 -105 Me. V/c The a 2(1320) is the dominant signal. There is a small (few %) exotic wave. Interference effects show a resonant structure in 1 -+. (Assumption of flat background phase as shown as 3. ) 11 May 14, 2003 Curtis A. Meyer -p -> - p (18 Ge. V) a 2 1

Exotic Quantum Numbers 1 -+ in Crystal Barrel Same strength as the a 2.

Exotic Quantum Numbers 1 -+ in Crystal Barrel Same strength as the a 2. 1(1400) Mass = 1400 +- 20 Me. V/c 2 Width= 310+-50+50 -30 Me. V/c 2 Without 1 c 2/ndf = 3, with = 1. 29 0 - 12 May 14, 2003 Curtis A. Meyer Produced from states with one unit of angular momentum.

Significance of signal. 13 May 14, 2003 Curtis A. Meyer

Significance of signal. 13 May 14, 2003 Curtis A. Meyer

E 852 Results Exotic Quantum Numbers 1 -+ in At 18 Ge. V/c to

E 852 Results Exotic Quantum Numbers 1 -+ in At 18 Ge. V/c to partial wave analysis 14 May 14, 2003 Curtis A. Meyer suggests

Exotic Quantum Numbers 1 -+ in E 852 Results Correlation of Phase & Intensity

Exotic Quantum Numbers 1 -+ in E 852 Results Correlation of Phase & Intensity Exotic Signal 1(1600) Leakage From Non-exotic Wave due to imperfectly understood acceptance 15 May 14, 2003 Curtis A. Meyer 3 m=1593+-8+28 -47 G=168+-20+150 -12

Exotic Quantum Numbers 1 -+ in ’ The 1(1600) is the Dominant signal in

Exotic Quantum Numbers 1 -+ in ’ The 1(1600) is the Dominant signal in ’. Mass = 1. 597 0. 010 Ge. V Width = 0. 340 0. 040 Ge. V 1(1600) ’ Other reports here: 1(1600) b 1 1(1600) f 1 , b 1 , f 1 , ’ 16 May 14, 2003 Curtis A. Meyer E 852 Results -p ’ -p at 18 Ge. V/c

VES Results Exotic Quantum Numbers 1 -+ in , b 1 and ’ m=1.

VES Results Exotic Quantum Numbers 1 -+ in , b 1 and ’ m=1. 6 0. 02 Ge. V/c 2 G=0. 29 0. 03 Ge. V/c 2 1(1600) observed in A reactions b 1 : ’ : = 1 : 1. 0 0. 3 : 1. 6 0. 4 -A (A) (at 37 Ge. V/c) b 1 (1 -+) Phase wrt 2+ 17 May 14, 2003 Curtis A. Meyer

Exotic Signals 1(1400) Width ~ 0. 3 Ge. V, Decays: only weak signal in

Exotic Signals 1(1400) Width ~ 0. 3 Ge. V, Decays: only weak signal in p production (scattering? ? ) strong signal in antiproton-deuterium. 1(1600) Width ~ 0. 16 to 0. 3 Ge. V, Decays , ’ , (b 1 ) Only seen in p production, (E 852 + VES) In a nonet, there should only be one 1 state. 1 IG(JPC)=1 -(1 -+) K 1 IG(JPC)= ½ (1 -) 1 IG(JPC)=0+(1 -+) ’ 1 IG(JPC)=0+(1 -+) Both of these are lighter than expectations, and The [ ’] decay modes are not what are expected. 18 May 14, 2003 Curtis A. Meyer

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3,

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3, f 3, K 3 2, 2, f 2, K 2 L=2 , , f , K 1 1 2, 2, ’ 2, K 2 3 -2 -1 -2 -+ a 2, f’ 2, K 2 a 1, f’ 1, K 1 L=1 a , f’ , K 0 0 b 1, h’ 1, K 1 2++ 1++ 0++ 1+- , , f, K* L=0 , , ’, K 1 -0 -+ 19 May 14, 2003 Curtis A. Meyer S=0 : 1++, 1 -S=1 : 0 -+, 1+-, 2 -+ Non-exotic hybrid QN’s

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3,

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3, f 3, K 3 2, 2, f 2, K 2 L=2 , , f , K 1 1 2, 2, ’ 2, K 2 3 -2 -1 -2 -+ a 2, f’ 2, K 2 a 1, f’ 1, K 1 L=1 a , f’ , K 0 0 b 1, h’ 1, K 1 2++ 1++ 0++ 1+- , , f, K* L=0 , , ’, K 1 -0 -+ 20 May 14, 2003 Curtis A. Meyer S=0 : 1++, 1 -S=1 : 0 -+, 1+-, 2 -+ Non-exotic hybrid QN’s 1 st radial excitation a 1, f’ 1, K 1

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3,

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3, f 3, K 3 3 - 2, 2, f 2, K 2 2 -L=2 , w , f , K -1 1 1 11 2, 2, ’ 2, K 2 2 -+ a 2, f’ 2, K 2 a 1, f’ 1, K 1 L=1 a , f’ , K 0 0 b 1, h’ 1, K 1 2++ 1++ 0++ 1+- , , f, K* L=0 , , ’, K 1 -0 -+ 21 May 14, 2003 Curtis A. Meyer S=0 : 1++, 1 -S=1 : 0 -+, 1+-, 2 -+ Non-exotic hybrid QN’s L=2 orbital excitation 1 st/2 nd radial excitation , w, f, K*

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3,

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3, f 3, K 3 2, 2, f 2, K 2 L=2 , , f , K 1 1 2, 2, ’ 2, K 2 3 -2 -1 -2 -+ a 2, f’ 2, K 2 a 1, f’ 1, K 1 L=1 a , f’ , K 0 0 b 1, h’ 1, K 1 2++ 1++ 0++ 1+- , , f, K* L=0 , , ’, K 1 -0 -+ 22 May 14, 2003 Curtis A. Meyer S=0 : 1++, 1 -S=1 : 0 -+, 1+-, 2 -+ Non-exotic hybrid QN’s 2 nd radial excitation , , ’, K

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3,

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3, f 3, K 3 2, 2, f 2, K 2 L=2 , , f , K 1 1 2, 2, ’ 2, K 2 2++ 1++ 0++ 1+- , , f, K* L=0 , , ’, K 1 -0 -+ May 14, 2003 S=1 : 0 -+, 1+-, 2 -+ Non-exotic hybrid QN’s 3 -2 -1 -2 -+ a 2, f’ 2, K 2 a 1, f’ 1, K 1 L=1 a , f’ , K 0 0 b 1, h’ 1, K 1 23 S=0 : 1++, 1 -- Curtis A. Meyer 1 st radial excitation b 1, h’ 1, K 1

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3,

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3, f 3, K 3 3 - 2, 2, f 2, K 2 2 -L=2 , , f , K 1 1 1 - 2, 2, ’ 2, K 22 -+ a 2, f’ 2, K 2 a 1, f’ 1, K 1 L=1 a , f’ , K 0 0 b 1, h’ 1, K 1 2++ 1++ 0++ 1+- , , f, K* L=0 , , ’, K 1 -0 -+ 24 May 14, 2003 Curtis A. Meyer S=0 : 1++, 1 -S=1 : 0 -+, 1+-, 2 -+ Non-exotic hybrid QN’s L=2 orbital excitation plus radial 2, 2, ’ 2, K 2

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3,

Hybrid Mesons with normal QN’s Assume that 1(1600) sets the mass scale 3, 3, f 3, K 3 3 - 2, 2, f 2, K 2 2 -L=2 , w , f , K -1 1 1 11 2, 2, ’ 2, K 22 -+ a 2, f’ 2, K 2 a 1, f’ 1, K 1 L=1 a , f’ , K 0 0 b 1, h’ 1, K 1 2++ 1++ 0++ 1+- , , f, K* L=0 , , ’, K 1 -0 -+ 25 May 14, 2003 Curtis A. Meyer S=0 : 1++, 1 -S=1 : 0 -+, 1+-, 2 -+ 2, 2, ’ 2, K 2 a 1, f’ 1, K 1 b 1, h’ 1, K 1 , w, f, K* , , ’, K Non-exotic hybrid QN’s

The 1++ Mesons 1++ : 1 st Radial Excitation of a 1(1260)/f 1(1285) a

The 1++ Mesons 1++ : 1 st Radial Excitation of a 1(1260)/f 1(1285) a 1(1640) m=1. 64 0. 05 Ge. V/c 2 G=0. 30 0. 1 Ge. V/c 2 Decays to 3 via f 2 and ( )S Consistent with a normal meson 26 May 14, 2003 Curtis A. Meyer

The 1 -- Mesons 1 -- : 1 st Radial Excitation of /. 2

The 1 -- Mesons 1 -- : 1 st Radial Excitation of /. 2 nd Radial Excitation of /. L=2 D-wave ( 1, 2, 3) (1450) (1420) (1700) (1650) f(1680) L=2 Scale 3(1690) 3(1670) f 3(1850) (1900) (2150) Decay modes are significant here, but data is hard to interpret. 27 May 14, 2003 Curtis A. Meyer

The 0 -+ Mesons (1800) m=1. 801 0. 013 Ge. V/c 2 G=0. 210

The 0 -+ Mesons (1800) m=1. 801 0. 013 Ge. V/c 2 G=0. 210 0. 015 Ge. V/c 2 Decays: f 0(980) , f 0(1370) , , , a 0(980) , f 0(1500) Speculation that this may be a hybrid (1760) Produced in J/ , decays to 4 (2225) m=2. 230 0. 050 Ge. V/c 2 G=0. 150 large Ge. V/c 2 Produced in J/ , decays to ff 28 May 14, 2003 Curtis A. Meyer Glueball quantum numbers

The 1+- Mesons 1+- : 1 st Radial Excitation of the b 1(1235)/h 1(1170)

The 1+- Mesons 1+- : 1 st Radial Excitation of the b 1(1235)/h 1(1170) h 1(1595) m=1. 594 0. 05 Ge. V/c 2 G=0. 384 0. 15 Ge. V/c 2 Produced in p interactions Decays to Consistent with a normal meson ? 29 May 14, 2003 Curtis A. Meyer

The 2 -+ Mesons m=1. 67 0. 02 Ge. V/c 2 G=0. 259 0.

The 2 -+ Mesons m=1. 67 0. 02 Ge. V/c 2 G=0. 259 0. 001 Ge. V/c 2 Decays: f 2 , , ( )S , fo(1370) , KK* (f 2 is 56%) 2(1670) m=1. 617 0. 005 Ge. V/c 2 2(1645) G=0. 181 0. 011 Ge. V/c 2 Decays: a 2 , KK , ao (a 2 is largest) 2(1870) m=1. 842 0. 008 Ge. V/c 2 G=0. 225 0. 014 Ge. V/c 2 Decays: a 2 , f 2 , ao (a 2 is largest) m=2. 090 0. 030 Ge. V/c 2 2(2100) G=0. 625 0. 100 Ge. V/c 2 Decays: f 2 , , ( )S 30 May 14, 2003 Curtis A. Meyer Hybrid Candidate?

Exotics and QCD In order to establish the existence of gluonic excitations, We need

Exotics and QCD In order to establish the existence of gluonic excitations, We need to establish the nonet nature of the 1 -+ state. We need to establish at other exotic QN nonets – the 0+- and 2+-. In the scalar glueball sector, the decay patterns have provided the most sensitive information. I expect the same will be true in the hybrid sector as well. DECAY PATTERS ARE CRUCIAL 31 May 14, 2003 Curtis A. Meyer

Results on Scalars s Crystal Barrel Discovery of the f 0(1500) a , ,

Results on Scalars s Crystal Barrel Discovery of the f 0(1500) a , , ’, KK, 4 Solidified the f 0(1370) a 4 Establishes the scalar nonet Discovery of the a 0(1450) 700, 000 0 Events f 2(1565)+s 250, 000 0 Events f 0(1500) f 2(1270) f 0(980) f 0(1500) 32 May 14, 2003 Curtis A. Meyer

The f 0(1500) Is it possible to describe the f 0(1500) as a member

The f 0(1500) Is it possible to describe the f 0(1500) as a member of a meson nonet? Use SU(3) and OZI suppression to compute relative decays to pairs of pseudoscalar mesons Get an angle of about 143 o 90% light-quark 10% strange-quark Both the f 0(1370) and f 0(1500) are 33 May 14, 2003 Curtis A. Meyer

WA 102 Results CERN experiment colliding p on a hydrogen target. Central Production Experiment

WA 102 Results CERN experiment colliding p on a hydrogen target. Central Production Experiment Recent comprehensive data set and a coupled channel analysis. 34 May 14, 2003 Curtis A. Meyer

Meson Glueball Mixing Physical Masses f 0(1370), f 0(1500), f 0(1710) Bare Masses: m

Meson Glueball Mixing Physical Masses f 0(1370), f 0(1500), f 0(1710) Bare Masses: m 1, m 2, m. G (G) (S) (N) f 0(1370) -0. 69 0. 07 0. 15 0. 01 0. 70 0. 07 f 0(1500) -0. 65 0. 04 0. 33 0. 04 – 0. 70 0. 07 octet piece f 0(1710) 0. 39 0. 03 0. 91 0. 02 0. 15 0. 02 m 1=1377 20 m 2=1674 10 m. G=1443 24 Lattice of about 1600 35 May 14, 2003 Curtis A. Meyer

Glueball Expectations Antiproton-proton: Couples to Observe: f 0(1370), f 0(1500) Central Production: Couples to

Glueball Expectations Antiproton-proton: Couples to Observe: f 0(1370), f 0(1500) Central Production: Couples to G and in phase. Observe: f 0(1370), f 0(1500), weaker f 0(1710). Radiative J/ : Couples to G, |1>, suppressed |8> Observe strong f 0(1710) from constructive |1>+G Observe f 0(1500) from G Observe weak f 0(1370) from destructive |1>+G Two photon: Couples to the quark content of states, not to the glueball. Not clear to me that has been seen. 36 May 14, 2003 Curtis A. Meyer

Higher mass glueballs? Part of the CLEO-c program will be to search for glueballs

Higher mass glueballs? Part of the CLEO-c program will be to search for glueballs in radiative J/ decays. Lattice predicts that the 2++ and the 0 -+ are the next two, with masses just above 2 Ge. V/c 2. Radial Excitations of the 2++ ground state L=3 2++ States + Radial excitations f 2(1950), f 2(2010), f 2(2300), f 2(2340)… 2’nd Radial Excitations of the and ’, perhaps a bit cleaner environment! (I would Not count on it though…. ) I expect this to be very challenging. 37 May 14, 2003 Curtis A. Meyer

The Future The CLAS experiment at Jefferson Lab is opening a small window to

The Future The CLAS experiment at Jefferson Lab is opening a small window to meson spectroscopy in photoproduction. CLEO-c will reopen the J/ studies with 100 times Existing statistics. One goal is to find and study the Pseudoscalar (0 -+) and tensor glueball (2++) The Glue. X experiment will be able to do for hybrids what Crystal Barrel and WA 102 (together) did for glueballs. What are the properties of static glue in hadrons and how is this connected to confinement. The antiproton facility at GSI (HESR) will look for hybrids in the charmonium system. (Just approved by the German government. ) 38 May 14, 2003 Curtis A. Meyer

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QCD Potential ground-state excited flux-tube m=1 m=0 linear potential Gluonic Excitations provide an experimental

QCD Potential ground-state excited flux-tube m=1 m=0 linear potential Gluonic Excitations provide an experimental measurement of the excited QCD potential. Observations of exotic quantum number nonets are the best experimental signal of gluonic excitations. 41 May 14, 2003 Curtis A. Meyer

Strong QCD See and systems. Color singlet objects observed in nature: Quarks in 3

Strong QCD See and systems. Color singlet objects observed in nature: Quarks in 3 colors white 8 Gluons carry color & anticolor white Focus on “light-quark mesons” Glueballs Allowed systems: 42 May 14, 2003 Curtis A. Meyer Hybrids 4 -quark , ,

Nonet Mixing The I=0 members of a nonet can mix: SU(3) Ideal Mixing: 43

Nonet Mixing The I=0 members of a nonet can mix: SU(3) Ideal Mixing: 43 May 14, 2003 Curtis A. Meyer physical states

Model for Mixing meson Glueball meson flavor blind? 1 r 2 r 3 r

Model for Mixing meson Glueball meson flavor blind? 1 r 2 r 3 r Solve for mixing scheme F. Close: hep-ph/0103173 44 May 14, 2003 Curtis A. Meyer

Scalar Mesons Overpopulation Strange Decay Patterns Seen in glue-rich reactions Not in glue-poor What

Scalar Mesons Overpopulation Strange Decay Patterns Seen in glue-rich reactions Not in glue-poor What about 2++ and 0 -+ ? J/Y Decays? Awaiting CLEO-c Glueball and Mesons are mixed. Scheme is model dependent. Crystal Barrel proton-antiproton annihilation The Scalar Mesons Central Production WA 102 Three States f 0(1370) f 0(1500) f 0(1710) 45 May 14, 2003 0++ 1. 5 Curtis A. Meyer 2. 5 0++ ss 1. 5 2. 5

Decays of Glueballs? Glueballs should decay in a flavor-blind fashion. ’=0 is true for

Decays of Glueballs? Glueballs should decay in a flavor-blind fashion. ’=0 is true for any SU(3) singlet and for any pseudoscalar mixing angle. Only an SU(3) “ 8” can couple to ’. Flavor-blind decays have always been cited as glueball signals. 46 May 14, 2003 Curtis A. Meyer