The The p p K K + + and and p p K K + + 0 0 reactions reactions at SPring-8/LEPS at SPring-8/LEPS Mizuki Sumihama Mizuki Sumihama RCNP, Osaka Univ. RCNP, Osaka Univ. for the LEPS for the LEPS collaboration collaboration HYP2006 Oct. 13th 2006
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The g p K + L and g p K + S 0 reactions at SPring-8/LEPS
The g p K + L and g p K + S 0 reactions at SPring-8/LEPS. Mizuki Sumihama RCNP, Osaka Univ. for the LEPS collaboration. HYP2006 Oct. 13th 2006. K +. g. N, N * , D *. p. Y( L, S 0 ). Physics motivation. Missing resonances N* and D * in s-channel. - PowerPoint PPT Presentation
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The The p p K K++ and and p p KK++00 reactions reactions
for the LEPS collaborationfor the LEPS collaboration
HYP2006 Oct. 13th 2006
Physics motivationPhysics motivation
It is essential to fully know It is essential to fully know NN** and and ** to understand to understand baryon structure.baryon structure.Many nucleon resonances Many nucleon resonances predicted by quark model predicted by quark model are are still missingstill missing..
DD1313(1900) (1900) resonanceresonance in in SAPHIR / CLAS data was SAPHIR / CLAS data was foundfound
K+
Y()p
N, N*, *
Some resonances should couple to K or Kchannel.Kaon photoproduction is good means
to search for missing resonances.
Missing resonances N* andMissing resonances N* and * * in s-channelin s-channel
Meson exchange in t-channelMeson exchange in t-channel
K+
Y()p
K*, K, K1
E = 1.5 2.4 GeVTransition region, s-channel t-
channelContribution of t-channel meson
exchangebecomes large above 2GeV.
Photon-beam asymmetry natural parity exchange (K*) = + 1unnatural parity exchange (K, K1) =- 1 at t = 0 and large E.
K+K*-exchange by M. Guidal.Isobar + Regge by T. Mart and C. Bennhold. Gent isobar model by T. Corthals
data
Polarization observable is important in order to fix the model parameters (fine optimization) and understand the Kaon Photoproduction, including the existence of a missing resonance -D13???.
Positive sign
Differential cross sections Differential cross sections for for p p p p00
LEPS dataOld dataCurves SAID(fit data at E < 2GeV)
Good agreement with SAID Photon normalization is OK.
Meson photoproduction in u-Meson photoproduction in u-channelchannel
0
Missing mass for p pX
We will obtain differential cross section and photon asymmetry for ’and.
Measure photon-beam asymmetry at backward angles where no data.
for for p p p p00
LEPS dataOld dataCurves SAID
Detect protons by forward spectrometer.
SummarySummaryThe KThe K+ + photoproduction was measured by linearly polarized photoproduction was measured by linearly polarized photons at SPring-8/LEPS. photons at SPring-8/LEPS. Photon-beam asymmetry is good tool to define theoretical Photon-beam asymmetry is good tool to define theoretical models.models.Differential cross sections were obtained at very forward Differential cross sections were obtained at very forward angles, up to cosangles, up to coscmcm = 0.975. = 0.975.Bump structure was seen at W=1960 MeV in the KBump structure was seen at W=1960 MeV in the K++ mode. mode. We see a forward peaking in KWe see a forward peaking in K++while no peaking in Kwhile no peaking in K++00..In order to fit the forward-angle data, a Regge pole is In order to fit the forward-angle data, a Regge pole is necessary in addition to s-channel resonances and t-channel necessary in addition to s-channel resonances and t-channel K and K*-exchanges. K and K*-exchanges. Combination of isobar (Feynman) and Regge is successful to Combination of isobar (Feynman) and Regge is successful to explain this forward peaking in Kexplain this forward peaking in K++..Photon normalization was checked by Photon normalization was checked by p p p p00 cross sections. cross sections.
The data show a good agreement with SAID. LEPS photon The data show a good agreement with SAID. LEPS photon normalization is OK. normalization is OK. Photon asymmetry data are obtained at backward angles. Photon asymmetry data are obtained at backward angles.
M. Sumihama et al. PRC73, 035214 (2006) M. Sumihama et al. PRC73, 035214 (2006) R.G.T. Zegers, M.Sumihama et al. PRL 91, 092001-1 R.G.T. Zegers, M.Sumihama et al. PRL 91, 092001-1
(2003). (2003).
LEPS collaborationLEPS collaborationD.S. Ahn, J.K. Ahn, H. Akimune, Y. Asano, W.C. Chang, S. Date, H. Ejiri, H. Fujimura, M. Fujiwara, K. Hicks, K. Horie, T. Hotta, K. Imai, T. Ishikawa, T. Iwata, Y.Kato, H. Kawai,
Z.Y. Kim, K. Kino, H. Kohri, N. Kumagai, Y.Maeda, S. Makino, T. Matsumura, N. Matsuoka, T. Mibe, M. Miyabe, Y. Miyachi, M. Morita, N. Muramatsu, T. Nakano, Y. Nakatsugawa, M. Niiyama, M. Nomachi, Y. Ohashi, T. Ooba, H. Ookuma, D. S. Oshuev, C. Rangacharyulu, A. Sakaguchi, T. Sasaki, T. Sawada, P. M. Shagin, Y. Shiino, H. Shimizu, S. Shimizu, Y. Sugaya, M. Sumihama H. Toyokawa, A. Wakai, C.W. Wang, S.C. Wang, K. Yonehara, T. Yorita, M.
Yosoi and R.G.T. Zegers, a Research Center for Nuclear Physics (RCNP), Ibaraki, Osaka 567-0047, Japan
b Department of Physics, Pusan National University, Pusan 609-735, Koreac Department of Physics, Konan University, Kobe, Hyogo 658-8501, Japan
d Japan Atomic Energy Research Institute, Mikazuki, Hyogo 679-5148, Japane Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
f Japan Synchrotron Radiation Research Institute, Mikazuki, Hyogo 679-5198, Japanh School of physics, Seoul National University, Seoul, 151-747 Koreai Department of Physics, Ohio University, Athens, Ohio 45701, USA
j Department of Physics, Kyoto University, Kyoto, Kyoto 606-8502, Japank Laboratory of Nuclear Science, Tohoku University, Sendai 982-0826, Japan
l Department of Physics, Yamagata University, Yamagata, Yamagata 990-8560, Japanm Department of Physics, Chiba University, Chiba, Chiba 263-8522, Japan
n Wakayama Medical College, Wakayama, Wakayama 641-0012, Japano Department of Physics, Nagoya University, Nagoya, Aichi 464-8602, Japan
p Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japanq Department of Physics, University of Saskatchewan, Saskatoon, S7N 5E2, Canada
r Department of Applied Physics, Miyazaki University, Miyazaki 889-2192, Japan