The meson landscape

transcript

The meson landscape

Scalars and Glue in Strong QCD

New states beyond

Weird baryons: pentaquark problems

“Diquarks,Tetraquarks, Pentaquarks and no quarks”

Theory to Reality via Lattice&Jlab

Strong

Only discuss hadrons that are either

Agreed to experimentally exist

Agreed to experimentally existAgreed experimentally to exist

Agreed theoretically should exist

Life is hard enough anyway and theorists are easily led astray

ArndtBuccellaCarlsonDyakanovEllisFaberGianniniHuangInoueJaffeKarlinerLipkinMaltmanNussinovOhPolyakovQiangRosnerStechTrillingUVenezianoWilczekXiangYangZhu

If Theta pentaquark doesn’t exist,then these (and many other theorists)should be congratulated on their creativity

Pentaquark

Somethings are deceptively simple

m(Bc) = 6276.5 (4.0) (2.7)

m(c)+m(b) ~ ½[m(psi) + m(upsilon)] = 6278.6

Heavy mass scale of c and b make agreements look artificially good

better than 1 per mille !

m(Bc) = 6276.5 (4.0) (2.7)

m(c)+m(b) ~ ½[m(psi) + m(upsilon)] = 6278.6

Heavy mass scale of c and b make agreements look artificially good

better than 1 per mille !

WHY does it work so well? Constituent d.o.f.robust=gift of nature

2S: 1-

1S: 1-

1D: 1-

Narrow below MM threshold

Anothergift of nature

2S: 1-

1S: 1-

1D: 1-

Lattice QCD: Linear: Flux tube…..implies…

Gluonic hybrid mesons

e.g. p=1e.g. p=1

Exciting the flux tube

Lattice&model agree spectrum; decays in FT; starting in lattice

2S: 1-

1S: 1-

1D: 1-

770 780/1020

I=1 vector : I=0 nn*; ss*

1320 1270/1525

1300 1285/1530

+ Problem of nn* ss* flavour mixing

Clean below S-wave MM thresholdsAnd no prominent G expected45

2S: 1-

1S: 1-

1D: 1-

770 780/1020

I=1 vector : I=0 nn*; ss*

1320 1270/1525

1300 1285/1530

1420 1370/1500/1710

+ Problem of nn* ss* flavour mixing

2S: 1-

1S: 1-

1D: 1-

I=1 vector : I=0 JP = 2+ 1+ 0+

13201270/1525

13001285/1530

1420 1370/1500/1710980 980/600

Far away from qq* lowest multiplets… except for 0++

Glueballs spectrum in YangMills from Lattice

Optimist: is this a signal for scalar glueball?

Only scalar glueballbelow 2 GeV

Glueballs spectrum in YangMills from Lattice

Optimist: is this a signal for scalar glueball?

2S: 1-

1S: 1-

1D: 1-

I=1 vector : I=0 JP = 2+ 1+ 0+

13201270/1525

13001285/1530

1420 1370/1500/1710980 980/600

? qq* + Glueball

Lattice G =1.6 \pm

2S: 1-

1S: 1-

1D: 1-

I=1 vector : I=0 JP = 2+ 1+ 0+

13201270/1525

13001285/1530

1420 1370/1500/1710980 980/600

[qq][q*q*]

2S: 1-

1S: 1-

1D: 1-

I=1 vector : I=0 JP = 2+ 1+ 0+

13201270/1525

13001285/1530

1420 1370/1500/1710980 980/600

Data do not imply GBut given lattice and qq*Does consistent pic emerge?

Can data eliminate it; or even make it robust?

Scalar Glueball and Mixing

Meson G ss* nn*

1710 0.39 0.91 0.15

1500 - 0.65 0.33 - 0.70

1370 0.69 - 0.15 - 0.70

LEAR/WA102Meson pair decays

Meson G ss* nn*

1710 0.39 0.91 0.15

1500 - 0.65 0.33 - 0.70

1370 - 0.69 0.15 0.70

0- 0- meson decays LEAR/WA102

FC Kirk

Scalar Glueball and Mixinga simple example for expt to rule out

Nontrivial correlationwith relative masses

lightmiddle

Scalar Glueball and Mixing:how to measure flavour state

Meson G ss* nn*

1710 0.39 0.91 0.15

1500 - 0.65 0.33 - 0.70

1370 0.69 - 0.15 - 0.70

Meson G ss* nn*

1710 0.39 0.91 0.15

1500 - 0.65 0.33 - 0.70

1370 0.69 - 0.15 - 0.70

from BES

A flavour filter for 0++ 0-+ 2++mesons and glueballs

>1 billion 1000 per meson

Challenge: Turn Lattice QCD Glueball spectrum into physics31

flux-tube degrees-of-freedom

e.g. p=1e.g. p=1

Costs about 1 to 1.5GeV energy to excite phonon“pi/R”Hybrid qq* @ 2GeV; Hybrid cc* @ 4-4.5GeV

Barnes FC Swanson 93

Exotic 1-+ clean example

\sim 2.2 GeV ss* quarks LGT \sim 2 GeV ud flavours

Michael…

Light flavor dangerPi very light = bigger threat e.g. pi b1 below 1-+ hybrid

Heavy flavors: K D B more “normal”KK1 threshold vs ss*hybridDD1 threshold versus cc* hybridBB1 threshold versus bb* hybrid27/26

Predicted 1-+ Hybrid masses (with spin splittings)

“Hybrid” and 3^3S_1almost decoupled

Predicted 1-+ Hybrid masses (with spin splittings)

Spin hyperfine splittings

1- - (4.25) Y(4260?)1- + (4.1) HQLGT0- + (3.95) X(3940?)

Barnes FC 82Chanowitz Sharpe

e+e- feebly coupled

e+e- \to \psi + X?

e+e- \to psi pi pi BaBar sees new vector cc*

Y(4260)

No sign of established3S/2D(4040/4160)4S(4400)in the psi pipi data

Y(4260) thus seemsanomalous

Also no place for extra cc* state

\Gamma(ee) 5-80eVCompare \sim 1 keV !!

But width 90MeV dominantly psi pipi !

Belle e+e- to + X

0-+;1-+

Masses OK. Need to go

Beyond spectroscopy:

Hybrid decays and production.

What are the general properties of OZI strong decay?

What properties

Michael McNeile 06

FC Burns 06

confirms Flux Tube for hybrid:conventional

Lattice S-wave decays now calculated Michael McNeile

Exactly WHAT is Lattice revealing about dynamics:What aspect(s) of Flux Tube model are being confirmed?

qq* create in S=1

qq* create in S=0 0

J – S = “L” Factorisation of S and L

qq* created in S=1

S=0 cannot decay to S=0 + S=0 “spin singlet selection rule”

Factorisation and S=1 creationis powerful result if generally true.

Determine nature of Y(4260) by DD_1 pattern

SL Factorisation and S=1selection rules for psi*(cc*) \to DD_1

Also applies to KK_1 decays of ss* vectorse.g. Jlab around 2.2 GeV

e+e- KK_1

phi pi pi

Intriguing resonantsignal at 2175

= phi(hybrid)??

2175 – m(phi)=4265 – m(psi)!!??

Jlablook indiffractive

4260 decay if hybrid

Do data fit with this?

What next (theory and data)

flux-tube breaking and hybrid decays

e.g. p=1e.g. p=1

Break tube: S+P states yes; S+S suppressed

Isgur Paton 92 light exotics

FC Page 95 all

e.g. p=1e.g. p=1

FC Page 95 all

Look for DD_1 and D*D_0 near threshold Look for psi pipi and h1c eta

e.g. p=1e.g. p=1

FC Page 95 all

Look for DD_1 and D*D_0 near threshold Look for psi pipi and h1c eta

Absence of DD; DD*; DsDs …

Y(4260): D_s and D_s* channels

NoDsDsresonance

eliminatestetraquarkcsc*s*

Y(4260): D and D* channels

NoDDDD* orD*D*resonance

The large psi +pi pi = hint of large DD1

D_1 uu * pi pi

e+e- psi(hybrid) DD_1

S-wave, relative mom \sim 0; DD_1 interchange constituents to make psi pipi “strongly”

Similar for phi(hybrid) KK_1 phi pipi 48/5

All consistent with predictions for hybrid charmoniumFC+Page 1995

Search DD_1 and D*D_0 in DD\pi\pi

If NOT hybrid cc* then why not/where is it ?!

Can glueballs ever be (dis)proven?

Are valence hybrids drowned by continuum mesons?

Heavy flavours cleaner thy but less interesting for Jlab

ss*g & qq*g at Jlab – flavour dependence and sort out phenom

Lattice challenge = is there 1-+ qq*g signal or is it pi b1 where is the valence hybrid in mass

Lattice challenge = do hybrids really prefer S+P decays(a lot of phenomenology/expt prejudice based on it)

General challenge: rate for hybrid photo/electroprod sum rules = not suppressed (hidden assumptions) models primitive

gamma rho

hybrid

yes no

Model assumed this

gamma rho

hybrid

gamma rhohybrid

hybrid

Model assumed this

Model ignored this

Lattice radiative transitions now in progress (heavy flavors)Jlab group……hope for intuition on light flavour rates for Jlab

JLab Hybrids: Theory

JLab Hybrids: Experiment

Diffractive production of 1– at 2175MeV into phi pipi; KK1Hybrid S=0 cant make S=0+S=0: K+K(1P1)=0 test.K1(3P1:1P1) tests for 3S1:3D1:hybrid vector

Meson G ss* nn*

1710 + + +1500 - + - 1370 + - -

3 state mixingRelative phases

2S: 1-

1S: 1-

1D: 1-

29801S: 0-

36252S: 0-

Possible 0-+Glueball \sim 3.6 GeVImpact on eta_c’ ??

Compare in B decay, gamma gamma;ee \to psi + eta_c’

The meson landscape

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