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 –> K  g.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 N 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 Strategy Use fundamental symmetry relations as much as possible Chiral, flavor, u-spin, KR-asymmetry and so on (1)Kroll-Ruderman: Proton-neutron asymmetry (2) TW (g V =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-exchange reactions Particularly important for J = 3/2 J = 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   +  *,  n   +  *  p   0  *,  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 (g V =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 FF  Consistent with the low energy theorem Some confusions

Mar. 1-3, 2007 特定領域研究会鳥羽 11 Estimation PS PV T. Hyodo (YITP)

Mar. 1-3, 2007 特定領域研究会鳥羽 SU(3) symmetry violation?

Mar. 1-3, 2007 特定領域研究会鳥羽 13 SU(3) symmetry Current masses: m u, m d ~ 10 MeV, m s ~ 100 MeV BUT Constituent masses: m u *, m d * ~ 300 MeV, m s * ~ 400 MeV It is likely that SU(3) symmetry is good for basic interactions BUT may break through dynamical effects m  << m K => 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 known Kaon production: less understood Large ambiguities

Mar. 1-3, 2007 特定領域研究会鳥羽 15 Various couplings BennholdOzaki ~SU(3) Set1Set2 – 3.09–3.80– –0.19–0.51–0.07 – –0.08–0.31– –0.61–0.37 Weak Strong

Mar. 1-3, 2007 特定領域研究会鳥羽 16  p –> K +  Weak K* ~ SU(3) Strong K* Total SAPHIA W ~ 2.1 GeV

Mar. 1-3, 2007 特定領域研究会鳥羽 17  p –> K +  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 Asymmetry AA 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 large Weak => 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 LEPS CLAS SAPHIA  dependence LEPS SAPHIA Total