S-Y-05 S.H.Lee 1 1.Introduction 2.Theory survey 3.Charmed Pentaquark 4.Charmed Pentaquark from B...

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S-Y-05 S.H.LeeS-Y-05 S.H.Lee

1. Introduction

2. Theory survey

3. Charmed Pentaquark

4. Charmed Pentaquark from B decays

Physics of Pentaquarks

Su Houng LeeYonsei Univ., Korea

References: Y. Oh, H. Kim, Y. Kwon, S.H.Lee, : PRD, PLB’s S.H.Lee,k Y. Kwon : charmed pentaquark: in preparation

Mass= 1.54 GeV , width <25 MeV , quark content= uudds

1. LEPS coll., Nakano et.al. PRL 91 012002 (2003)

Introduction

)1520(

Verification

2. Verification by other group

4. NA49 hep-ex/0310014

found *(1862) in - - (ddss u) with width< 18 MeV

3. CLAS finds no ++ in K+ P invariant mass

+(udud s) belongs to anti-decuplet

(1232)

(1532)

(1673)

N(939)

(1190)

(1320)

Baryon Reprsentation

2. Could not confirm in subsequent experiments

CDF, ZEUS, FOCUS

1. H1 collaboration (Deep Inelastic scattering)

Heavy Pentaquarks (udud c)

c(3099) was found in D* p (uudd bar(c))

with width= 12+-3 MeV

Experimental summary

1. + controversial

mass 1540 MeV> KN threshold (1435 MeV)

2. c+ controversial

search was done with DN D*N final state (unbound)

> 2800 MeV +

Theory review

Soliton model + Quark model(biased and limited)

1. SU(3) soliton

2 4( ) ( )Kin Skyrme W ZL U L U L

†exp( ) 0( , ) ( ) ( )

where ( ) has 8 angles

i rU x t R t R t

2. Quantizing the 8 angles, the Hamiltonian becomes

3 72 2

1 41 2

1 1ˆ ˆ' '2 2

RotA A

H J JI I

10 8 8101 2

2 2E E E E

I=J Hedghog

Soliton model: original prediction (Diakanov, Petrov, Polyakov 97)

4. Diakanov Petrov Polyakov applied it to Anti decuplet

which predicted mass= 1540, width=30 MeV

1. only SU(3) representations containing Y=NcB/3+S= Nc /3 are allowed

2. moreover, the number of states 2I+1 at S=0 or Y= Nc/3 must determine the spin of the representation through 2J+1 because I=J in the SU(2) soliton

one spin state for given representation

3. With constraint coming from WZ term Y

3 3Y p q

1. Karlinear, Lipkin

diquark: C=3,F=3,S=0

triquark: C=3,F=6,S=1/2

Negative parity if all the quarks are in the lowest s-state

Positive parity if a relative p wave

But with this simple picture, it is not easy to understand small width

Quark models

2. Jaffe, Wilczek

Positive parity if a relative p wave

L=0, S=1/2 L=1 J=1/2 and 3/2 (higher mass)

color 3 3 3 1

But, a closer look revealed puzzles

1. Soliton picture is valid at large N_c:Semi-classical quantization is valid for slow rotation: ie. Valid for describing excitations of order 1/

N_c, so that it does not mix and breakdown with vibrational modes of order 1

2. Lowest representation SU(3)_f (p,q) at large N_cY

3 3Y p q

Quantization constraint requires max

3 3 3cNp q

1. Octet

2. Decuplet

3. Anti decuplet

(lowest representation containing s=1)

1(1, )

3(3, )

3(0, )

Naive Solition model should fail (T. Cohen)

3. Mass splitting in large N_c:

3 72 2

1 41 2

1 1ˆ ˆ' '2 2

RotA A

H J JI I

3 1( ),

NE E O

Anit decuplet octet mass splitting is mixes with vibrational mode and inconsistent with original assumption and has undetermined correction of same order

Rotation is too fast and may couple to vibrational modes, which might be important to excite q qbar mode, hence describing anti decuplet state with naïve soliton quantization might be wrong

1. SU(2) soliton+ Kaon

2. Successful for hyperon (attractive (s qbar) ) but no pentaquark (repulsive q sbar) from WZ term

2 4( ) ( )Kin Skyrme W ZL U L U L

Bound state approach for SU(3) soliton

Summary of Solition approach for + (ududs)

1. SU(3) Soliton

Inconsistent application

2. Bound state approach

No bound +

Can not be applied to heavy pentaquark c(ududc)

predict a bound heavy pentaquark c(ududc)

ie. mass is smaller than DN continuum

Quark model also predict a bound heavy pentaquark c(ududc) but no light pentaquark +(ududs)

Color spin interaction quark model

1. In QCD q-q are also attractive if in color anti-triplet channel.

Quark-antiquark, or Quark-Quark attaction in QCD

M SSmm

B SSmm

In perturbative QCD, 2CB=CM This term is called color spin interaction

Color spin interaction explains hadron spectrum

In perturbative QCD 3CB=CM = 635 MeV x ( mu )2

Nucleon

Color anti-triplet

Spin index sym s=1

Why there should be a heavy pentaquark

1. For Pentaquark L=0, S=1/2 L=1

color 3 3 3 1

2. If recombined into a D meson and Nucleon

Summary of Theory for Pentaquark

1. The only consistent Soliton approach predict only heavy pentaquark

2. Constituent quark model also predict only heavy pentaquark

may explain null result for light pentaquark

Could not observe heavy pentaqurk from DN finla state because it might be bound

Heavy pentaquark can only be observed from Weak decay

May be from B factory? But do we have sufficient data and can one conclude anything if one tries?

Anti-Charmed pentaquark from B decays

Can we understand Baryonic decay mode of B+

1. Baryonic decay mode

2. Can we explain it using Dominant hadronic decay mode

Baryonic decay mode of B+

1. Baryonic decay mode in hadronic language

Coupling ?Form factor?

Effective hadronic Lagrangian for heavy hadrons

Photo production of open charm, W.Liu, C.M.Ko, SHLee (03) NPA

Baryonic decay mode of B+

1. Baryonic decay mode in hadronic language

13.5MeV 750 ,

Obtain branching ratio of

experimental measurement

Pentaquark decay mode of B+

Using hadronic interactions as before, we find the branching ratio to be

Coupling=1

Branching ratio 0.092

Total events events 19)7.0)(092.0)(108.8)(10( 479

SummarySummary

1.1. Theory predicts no stable light pentaquark, but bound heaTheory predicts no stable light pentaquark, but bound heavy pentaquark vy pentaquark

might explain present null results

2. Baryonic decay mode of B+ can be sensibly estimated wit previously determined hadronic parameters

3. With present B+ data, can measure c from

If found the first exotic ever, will tell us about QCD and dense matter color superconductivity

S-Y-05 S.H.Lee 1 1.Introduction 2.Theory survey 3.Charmed Pentaquark 4.Charmed Pentaquark from B...

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