Qiang Zhao

Theory Division, Institute of High Energy Physics, CAS

1st FCPPL Conference, Marseille, Jan. 14 - 18, 2008

Institute of High Energy Physics, CASInstitute of High Energy Physics, CAS

Isospin violation and its correlation with OZI-evading process in quakonium hadronic decays

Isospin violation and its correlation with OZI-evading process in quakonium hadronic decays

Outline

• Topics on quarkonium hadronic decays

• France-China Collaboration on theoretical hadron physics

Contributors

Focus of hadron physics

• Complexity of QCD in the non-perturbative regime

exotic hadrons (glueball, hybrid, multiquarks …)

Baryon

qqq quark-diquark

Hybrid Pentaquark

Meson

qq

Hybrid

glueball

Focus of hadron physics

• Complexity of QCD in the non-perturbative regime exotic hadrons (glueball, hybrid, multiquarks …)

• Lattice QCD, QCD sum rules, effective theory… Phenomenological tools

• Break-down certain problems • Experimental information: Light hadron

spectroscopy (JLab, ELSA, MAMI, ERSF, Spring-8); Heavy quarkonium hadronic decays (BES, CLEO-c, Belle, BaBar, LHC…)

“ The primary goals of hadronic physics are to determine the relevant

degrees of freedom that govern hadronic phenomena at all scales, to establish the

connection of these degrees of freedom to the parameters and fundamental fields of QCD, and to

use our understanding of QCD to quantitatively describe a wide array of hadronic phenomena, ranging from terrestrial nuclear physics to the

behavior of matter in the early universe. ”

“Key issues in hadronic physics”

Charmed Physics Topics

• Quarkonium hadronic decays as a probe for light hadron spectroscopy

• Study of charmed baryons, and charmed exotic mesons

c(2980)J/(3096)

0 (L=0,S=0) 1 (L=0,S=1)

Ma

ss (

MeV

) DD threshold

c(2980)

Light mesons, , K*K, …

J/ hadronic decays

glue

c

c qq Meson

J/

• Glue-rich intermediate states• Ideal for the search for exotic states (hybrid, glueball …)

Mesonq

q

q

q

A probe of strong QCD dynamics

hybridglueball

J/

c

c uudd(I=0)

J/

c

c

(I=0)

ss(I=0)

= (uu + dd)/2 = ss

A flavour filter for Okubo-Zweig-Iizuka (OZI) disconnected transitions

V=

• Structure of the light hadrons: qq, glueball, multiquark, hybrid …• OZI rule violations• Isospin violations

(I=0)

qq (I=1)

Strong transition in 0

s

s

(I=0)

0 (I=1)

(I=0)

g

(I=0)

s

s

(I=0)

0 (I=1)

K (us)

K (su)

K0 (ds)

K0 (sd)

OZI evading process

K*

• Strong isospin violation via intermediate meson exchanges

If mu = md,

(a) + (b) = 0 and (c) + (d) = 0.

If mu md,

(a) + (b) 0 and (c) + (d) 0.

Li, Zhao and Zou, arXiv:0706.0384[hep-ph], PRD 77, 014010 (2008)

• t-channel versus s-channel

*, VMD

mixing

0

0

-0, -0 mixing

0

0

0

t-channel

Previous approach

This approach

Branching ratios for J/ (cc) V P

Same order of magnitude !

• What accounts for such a large isospin violation? • Implications of the “ puzzle” …

• Scalar a0(980)-f0(980) mixing in J/ f0(980) 0 via OZI evading and isospin violating process (Wu, Zhao, and Zou,

PRD(2007) ).

• Application to J/, ’ VP is useful for the study of “ puzzle” (Zhao, Li and Chang, PLB645, 173(2007) ) and search for pseudoscalar glueball (Li, Zhao and Chang, hep-ph/0701020).

• Intermediate D meson contributions to the M1 transitions in J/, c, ( c) (Li and Zhao, 0709.4639[hep-ph] ).

• Search for glueball signals in charmonium hadronic decays (F. Close and Zhao, PRD(2005), Zhao, PRD(2007); PLB(2008))

Relevant issues Relevant issues

A flavour filter for baryon-antibaryon production

J/

c

c

B (N, N*, , *, , *, , * …)

B

• “Missing resonances” (JLab, ELSA, ESRF, MAMI, Spring-8, … )• Baryon form factors • Exotic baryons

N B

N*,K,,‘,,…

B

N*…

N

,…

pi-N invariant mass / MC phase space

BES Collaboration, Phys. Rev. Lett. 97, 062001 (2006)“Observation of two new N* peaks …”

/J p n /J p n vs

P11(1440) N*(2060)

Zou/IHEP

BES

A proposal to FCPPL A proposal to FCPPL

Topics Topics

Z(4430) as tetraquark candidate, and its

production mechanism

Participants Participants

Expertise Expertise

QCD factorization

Quark models

QCD phenomenology with effective Lagrangian

QCD sum rules

Chiral perturbation theory

Lattice QCD

How to work together? How to work together?

1. Identify commonly interested questions to involve people in this working group

2. Regular visits between French and Chinese collaborators

3. Involvement of PhD students

4. …

Theoretical Physics Center for Science Facilities (TPCSF), CAS

Theory Division, IHEP/CAS

Prof. Bingsong Zou

Theoretical Physics Center for Science Facilities (TPCSF), CAS

Theory Division, IHEP/CAS

Prof. Bingsong Zou

Efforts full of challenges, but must be very rewarding !

Thanks !Thanks !

Three schemes for the numerical calculations of the intermediate meson exchange loops

1. On-shell approximation

2. Feynman integration with a monopole form factor

3. Feynman integration with a dipole form factor

1. On-shell approximation

0, No form factorn = 1, monopole 2, dipole

(GeV) : to be determined by experimental data.

Numerical results :

Experimental branching ratio:

On-shell approximation

underestimates the data.

Exclusive KK(K*) loop

EM and KK(K*) out of phase EM and KK(K*) in phase

• -dependence of the sum of EM and KK(K*) loop

Still underestimate the experimental data.

2. Feynman integration with a monopole form factor

Similarly for the neutral meson loop …

• -dependence of the exclusive KK(K*) loop with a monopole form factor

• -dependence of the exclusive KK*(K) loop with a monopole form factor

3. Feynman integration with a dipole form factor

Exclusive KK(K*) loop contribution to BR

Exclusive KK*(K) loop contribution to BR

Inclusive contributions from the isospin violating transitions

Isospin violation = EM Strong decay loops

Exp.

Exp.

In phase Out of phase

V V P is a P-wave decay, favors a dipole form factor.

• The correlation between the OZI-rule violation and strong isospin violations makes the intermediate meson exchange a possible dynamic solution for the study of isospin violations in 0.

• It provides an explicit way to separate the EM and strong isospin violation mechanisms, thus, is different from meson mixing scheme.

A Brief Summary A Brief Summary

a0(980) & f0(980) mixing

• Motivation for studying a0(980) & f0(980)

• Mechanism for a0(980)-f0(980) mixing

• Various predictions for a0-f0 mixing

• Possibility of measuring a0-f0 mixing from J/

• Conclusion

Bingsong Zou’s talk at Hadron 2007J.J. Wu, Q. Zhao and B.S. Zou, PRD2007

1. Motivation for studying a0(980) & f0(980)

a2(1320) uu -ddf2(1270) uu +dd

K2(1430) sd

f’2(1525) ss

qq tensor nonet

puzzling scalar nonet

qq , q2q2 , meson molecule ?

f0(980) ss , [suus +sdds ]

(800) sd , [suud ]

f0(600) uu +dd , [uddu ]

a0(980) uu -dd , [ussu -dssd ]

KK molecule by t-channel , , exchange ?

Yes, with = 5.7 GeV and drop momentum-dependent terms

- S.Kreward et al., PRD69, 016003 (2004)

No, if keep momentum-dependent terms

-Y.J.Zhang, H.C.Chiang, P.N.Shen, B.S.Zou, PRD74, 014013 (2006)

KK -qq mixture possible : E. van Beveren et al., PLB641 (2006) 265

a0-f0 mixing internal structure of a0-f0

-N.Achasov,S.Devyanin,G.Shestakov, PLB88, 367 (1979)

2. Mechanism for a0(980)-f0(980) mixing

*2

1 a af

af ff a af

D DG

D DD D D

2 2( ) ( ) ( ) ( )

2 22

( ) ( )

1 18 2

a a f fa a s s f f s sKK KK

b c b ca abcbc s bc s bc

D m s i s D m s i s

m m m mg sp ps s s

0 0 00 0

0 0

( ) ( )

2 2( ) ( )

8 ( )

s sf K K a K K K K K Kaf

s sK K K K

g g i p pD

s O p p

0 0 00 0

0 0 0 0 0 0 00 0 0

( ) ( )

2 2 2 2( ) ( ) ( )8

s sf K K a K K K K K Kaf

a a s s sa a K K K K a K K K K

g g p pD

D s m s i g p g p g p

Mixing ratio :

3. Various predictions for a0-f0 mixing

KK q2q2

qq

Model predictions Estimations from relevant measured parameters

For a very recent prediction from chiral unitary approach,cf. Hanhart, Kubis & Pelaez, arXiv:0707.0262 

No firm direct observation of a0-f0 mixing available !

Possible experiments to measure a0-f0 mixing

1) pp ppF.Close & A.Kirk, PLB489,24(2000)

p p f0(980) a0(980)

2) p p , N.Achasov & G.Shestakov, PRL92, 182001 (2004)

f0(980) a0(980)

3) dd3) dd , WASA-at-COSY Collaboration, nucl-ex/0411038

4) J/ , F.Close & A.Kirk, PLB489,24(2000)

4. Possibility of measuring a0-f0 mixing

from J/

BES collaboration,PLB607, 243 (2005)

f0(980) clearly observedin J/

How about f0(980) a0(980) ?

/Jf0(980)

KKJ /

f0(980)

a0-f0 mixing

/J J/

BG contributions

BR: a0-f0 mixing ~ (2-20)*10-6 , ~ 2.6*10-7 , K*K ~ (3.8 -12)*10-6

5. Conclusion

109 J/ events with BES3 detector

+

BR(J/ f0 a010-6

narrow 8 MeV peak ( 987.4 – 995.4 ) MeV

Clear & precise determination of a0-f0 mixing !

• Rich information about the strong QCD dynamics in the correlation between the OZI evading and isospin violation.

• Application to J/, ’ VP is useful for the study of “ puzzle” (Zhao, Li and Chang, PLB645, 173(2007) ) and search for pseudoscalar glueball (Li, Zhao and Chang, hep-ph/0701020).

• Intermediate D meson contributions to the M1 transitions in J/, c, ( c) (Li and Zhao, 0709.4639[hep-ph]).

• Search for glueball signals in charmonium hadronic decays (F. Close and Zhao, PRD(2005), Zhao, PRD(2007); PLB(2008))

• Experimental focuses of BES, CLEO-c, KLOE, B-factories…

Summary Summary