Determining the Determining the ++ quantum numbers quantum numbers through the Kthrough the Kp -> p ->

KK++n reaction n reaction

Determining the Determining the ++ quantum numbers quantum numbers through the Kthrough the Kp -> p ->

KK++n reaction n reaction

Tetsuo Hyodoa

a RCNP, Osaka b IFIC, Valencia

2003, August 8th

A. Hosakaa and E. Osetb

IntroductionIntroduction

+ : 5-quark (4 quark + 1 anti-quark)LEPS, T. Nakano et al., Phys. Rev. Lett. 91 (2003) 012002

Quantum numbers are not yet determined

We study K+p -> +K+n reaction todetermine the quantum numbers of +

Theory prediction Diakonov et al. (chiral quark soliton) Carlson et al. (quark model[QM]) Stancu et al. (QM + flavor-spin int.) Zhu (QCD sum rule) Capstick et al. (decay width analysis)

: 1/2+, I=0: 1/2, I=0: 1/2+, I=0: 1/2, I=0, 1, 2: 1/2, 3/2, 5/2, I=2

A model for p -> K0 A model for p -> K0

E. Oset and M.J. Vicente Vacas, PLB386, 39(1996)

Vertices are derived from the chiral Lagrangian

Proportional to vanishes

Assume final + is almost at rest

Dominant

DiagramsDiagrams

Tree level(background)

One loop

Possibilities of spin & parityPossibilities of spin & parity

1/2(KN s-wave resonance)1/2,3/2(KN p-wave resonance)

MR = 1540 MeV = 20 MeV

Resonance termResonance term

Amplitude of resonance term for K+p -> +K+n :

Angular dependenceAngular dependence

total resonance background

10

8

6

4

2

01.00.50.0-0.5-1.0

cosθ

10

8

6

4

2

01.00.50.0-0.5-1.0

cosθ5

4

3

2

1

01.00.50.0-0.5-1.0

cosθ

,I JP=0,1/2- ,I JP=0,1/2+

,I JP=0,3/2+

Mass distributionsMass distributions

10

8

6

4

2

015801560154015201500

MI

,I JP=0,1/2-

,I JP=0,1/2+

,I JP=0,3/2+kin( )=850 /Lab MeV cθ=0deg

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.015801560154015201500

MI

Polarization testPolarization test

Angular dependence : polarization testAngular dependence : polarization test

total resonance background

5

4

3

2

1

01.00.50.0-0.5-1.0

cosθ

20

15

10

5

01.00.50.0-0.5-1.0

cosθ5

4

3

2

1

01.00.50.0-0.5-1.0

cosθ

,I JP=0,1/2- ,I JP=0,1/2+

,I JP=0,3/2+

Polarization test

Mass distributions : polarization testMass distributions : polarization test

14

12

10

8

6

4

2

015801560154015201500

MI

,I JP=0,1/2-

,I JP=0,1/2+

,I JP=0,3/2+kin( )=850 /Lab MeV cθ=90deg

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.015801560154015201500

MI

Polarization test

ConclusionsConclusions

We calculate the p -> K0 reaction usinga chiral model, assuming the possible quantum numbers of + baryon.

� Resonance signal of the mass distribution is always seen in the forward direction. � If we find the resonance with polarization test, the quantum number of + can be determined as I=0, JP=1/2+

T. Hyodo, A. Hosaka, and E. Oset, nucl-th/0307105