Post on 18-Jan-2018
description
Mar. 1-3, 2007 特定領域研究会鳥羽 1
Photo-productions of Kaons and Hyperons
Atsushi Hosaka, RCNP, Osaka University
1. Chiral symmetry 1. Gauge inv.: Kroll-Ruderman term N –> K(1520), N –> K(1520) 2. Tomozawa-Weinberg
2. SU(3) symmetry violation? N –> Kg.s. and the use of polarization
Mar. 1-3, 2007 特定領域研究会鳥羽 2
Effective lagrangian method
Good physics intuitions if separated
NN Y, Q, …Y, Q, …
Higher order corrections are classified either one of them
Mar. 1-3, 2007 特定領域研究会鳥羽 3
StrategyUse fundamental symmetry relations as much as possible
Chiral, flavor, u-spin, KR-asymmetry and so on
(1) Kroll-Ruderman: Proton-neutron asymmetry(2) TW (gV=1)(3) Yukawa: F/D ratio, Decay pattern: (1405) –> KN, , etc(4) U-spin: 8 –> 10 process
Mar. 1-3, 2007 特定領域研究会鳥羽 4
Chiral symmetry 1: Gauge inv. Role of the Kroll-Ruderman term
Mar. 1-3, 2007 特定領域研究会鳥羽 5
present only for charge-exchangereactions
Particularly important for J = 3/2J = 1/2 の場合はそれほどでもない
p –> K(1520), n –> K
Mar. 1-3, 2007 特定領域研究会鳥羽 6
p –> K (1520) J = 3/2–
Nam-Hosaka-Kim, PRD 71:114012,2005
Energy dependence t or dependence
= 700 MeV <=> r ~ 0.8 fm
Mar. 1-3, 2007 特定領域研究会鳥羽 7
p p ++*, *, n n ++**
p p 00*, *, n n ––**
= 700 MeV <=> r ~ 0.8 fm
Mar. 1-3, 2007 特定領域研究会鳥羽 8
Chiral symmetry 2:Role of the Tomozawa-Weinberg
Mar. 1-3, 2007 特定領域研究会鳥羽 9
(, K) and (K, ) reactions KEK experiments
+
K K
Tomozawa-Weinberg term
TW
Forbidden due to offdiagnality
Tomozawa-Weinberg (gV=1)
Mar. 1-3, 2007 特定領域研究会鳥羽 10
Theoretical question
PS: Linear sigma model suited to dynamical description for chiral symmetry breaking BUT no convergence in perturbation better large k behavior
PV: Non-linear sigma model Good convergence at low momentum
At low energies, PV should be used with FFConsistent with the low energy theorem Some confusions
Mar. 1-3, 2007 特定領域研究会鳥羽 11
Estimation
PS
PSPV PV
T. Hyodo (YITP)
Mar. 1-3, 2007 特定領域研究会鳥羽 12
2. SU(3) symmetry violation?
Mar. 1-3, 2007 特定領域研究会鳥羽 13
SU(3) symmetry
Current masses: mu, md ~ 10 MeV, ms ~ 100 MeV BUTConstituent masses: mu*, md* ~ 300 MeV, ms* ~ 400 MeV
It is likely that SU(3) symmetry is good for basic interactions BUTmay break through dynamical effects m << mK
=> Strongly coupled meson-baryon dynamics Spontaneous breaking of chiral symmetry
Mar. 1-3, 2007 特定領域研究会鳥羽 14
Production of K and (1116)
Studied many years: BUT we can learn something essential now
• Can SU(3) relations be used?
• How strongly does the K* couple to N and Y?
Pion production: well knownKaon production: less understood Large ambiguities
Mar. 1-3, 2007 特定領域研究会鳥羽 15
Various couplingsBennhold Ozaki
~SU(3)Set1 Set2
– 3.09 –3.80 –4.091.23 1.20 0.78–0.19 –0.51 –0.07–0.12 0.67 0.16–0.08 –0.31 –0.11-0.08 –0.61 –0.37
€
gKΛN / 4π
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gKΣN / 4π
€
gKK*γ gK*ΛNV /4π
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gK*Kγ gK*ΛNT /4π
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gK*Kγ gK*ΣNV /4π
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gK*Kγ gK*ΣNT /4π
Wea
k
Stro
ng
Mar. 1-3, 2007 特定領域研究会鳥羽 16
p –> K+
Weak K* ~ SU(3)Strong K*
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TotalSAPHIA
W ~ 2.1 GeV
Mar. 1-3, 2007 特定領域研究会鳥羽 17
p –> K+
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E = 1.9 GeV, W ~ 2.1 GeV
dependence
SAPHIA
LEPS
CLAS
Weak K* ~ SU(3)Strong K*
Mar. 1-3, 2007 特定領域研究会鳥羽 18
p –> K+
Weak K* ~ SU(3)Strong K*
E = 1.9 GeV, W ~ 2.1 GeV
AsymmetryA
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0.5
- 0.5
LEPS
Asymmetry A
Mar. 1-3, 2007 特定領域研究会鳥羽 19
Role of K*
Strong K* => pn asymmetry is not so largeWeak => could be large due to contact term
Information of n-target is very important
Mar. 1-3, 2007 特定領域研究会鳥羽 20
Something is missing?
Meson clouds
Anomalous process
Magnetic
Spin 3/2
Mar. 1-3, 2007 特定領域研究会鳥羽 21
Summary
There are many important but not yet well understood physics
• Test of chiral symmetry: KR- and TW terms
• SU(3) relations holds? Vector meson couplings
Mar. 1-3, 2007 特定領域研究会鳥羽 22
LEPS data
-dependence
Asymmetry
+ : K* dominant– : K dominant
Mar. 1-3, 2007 特定領域研究会鳥羽 23
p –> K+
Weak K* ~ SU(3)Strong K*
E = 1.9 GeV, W ~ 2.1 GeV
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LEPS
CLAS
SAPHIA
dependence
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LEPS
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SAPHIATotal
1.6 2 2.4