Publications (12)14.02 Total impact

Article: Probing ΛΛ potential
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ABSTRACT: We determined scattering length and effective range of ΛΛ scattering for the ΛΛ relative energy (MΛΛ2MΛ) from ΛΛ threshold to 30 MeV/c2. Phase shift of the ΛΛ wave function which described by scattering length and effective range was determined by fitting the ΛΛ mass spectrum. The obtained scattering length 0.10+1.371.56± 0.04, and effective range 13.90+0.379.13± 10.53, fm is the most consistent with the values predicted by using a series of the Nijmegen soft core models NSC97's. However the predicted values by using the Nijmegen hard core model ND (Gmatrix), the extended soft core model ESC00, and the KyotoNiigata FSS are out of three standard deviations from the determined scattering parameters. Further, we determine ΛΛ potential by fitting the ΛΛ invariant mass spectrum using numerically solved ΛΛ wave function with twoGaussian shaped potential well. The ΛΛ scattering parameters derived from the wave function are found to be scattering length 0.09, and effective range 29.34 fm with a maximum hase shift of 2.4 deg.  [Show abstract] [Hide abstract]
ABSTRACT: We determine LambdaLambda scattering parameters from a LambdaLambda invariant mass spectrum that was obtained by 12C(K, K+LambdaLambda) reaction at the KEK Proton Synchrotron. In the framework of Watson's procedure, the obtained scattering length a{Lambda Lambda } =  0.10 { 2.37}{+ 0.45} ± 0.04 and effective range r{Lambda Lambda } = 13.90 {<  13.90}{> + 16.10} ± 9.48 {fm} are most consistent with the values predicted by using the Nijmegen soft core models (NSC97's). However, the predicted values by using the Nijmegen hardcore ND (Gmatrix) and the extended softcore (ESC00) models are out of two standard deviations from the determined scattering parameters. 
Article: Extraction of ΛΛ scattering length
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ABSTRACT: We determine ΛΛ scattering parameters from a ΛΛ invariant mass spectrum that was obtained by 12C(K, K+ΛΛ) reaction at the KEK Proton Synchrotron. In the framework of Watson's procedure, the obtained scattering length a ΛΛ = 0.10 +0.452.37 ± 0.04 and effective range rΛΛ =13.90 ><+16.1013.90 ± 9.48 fm are most consistent with the values predicted by using the Nijmegen soft core models (NSC97's). However, the predicted values by using the Nijmegen hardcore ND (Gmatrix) and the extended softcore (ESC00) models are out of two standard deviations from the determined scattering parameters.  [Show abstract] [Hide abstract]
ABSTRACT: The Theta+ was searched for via the K+p > pi+X reaction using the 1.2 GeV/c K+ beam at the K6 beam line of the KEKPS 12 GeV Proton Synchrotron. In the missing mass spectrum of the K+p > pi+X reaction, no clear peak structure was observed. Therefore a 90 % C.L. upper limit of 3.5 ub/sr was derived for the differential cross section averaged over 2degree to 22degree in the laboratory frame of the K+p > pi+Theta+ reaction. This upper limit is much smaller than the theoretical calculation for the tchannel process where a K0* is exchanged. From the present result, either the tchannel process is excluded or the coupling constant of g_{K*N\Theta} is quite small.  [Show abstract] [Hide abstract]
ABSTRACT: The Theta+ was searched for via the K+p>pi+X reaction using the 1.2 GeV/c K+ beam at the K6 beam line of the KEKPS 12 GeV Proton Synchrotron. In the missing mass spectrum of the K+p>pi+X reaction, no clear peak structure was observed. Therefore a 90% C.L. upper limit of 3.5 µb/sr was derived for the differential cross section averaged over 2° to 22° in the laboratory frame of the K+p>pi+Theta+ reaction. This upper limit is much smaller than the theoretical calculation for the tchannel process where a K0* is exchanged. From the present result, either the tchannel process is excluded or the coupling constant of gK*NTheta is quite small.  [Show abstract] [Hide abstract]
ABSTRACT: The Hdibaryon resonance was sought by a ΛΛ invariant mass spectrum that was obtained by the 12C (K,K+ΛΛX) reactions. We observed a bump near the ΛΛ threshold, as reported by the previous experiment (KEK E224), with better statistics. Data were compared with results of a cascade model calculation including ΛΛ final state interactions consistent with the newly measured binding energy of ΛΛ6He. No significant enhancements above levels of the model predictions were observed. The resulting upper limit for the production cross section of the H with a mass range between the ΛΛ and ΞN threshold is found to be 2.1 ± 0.6 (stat.) ± 0.1 (syst.) μb/sr at a 90% confidence level.  [Show abstract] [Hide abstract]
ABSTRACT: The Hdibaryon resonance was sought by a Lambda Lambda invariant mass spectrum that was obtained by the C12 (K,K+Lambda Lambda X) reactions. We observed a bump near the Lambda Lambda threshold, as reported by the previous experiment (KEK E224), with better statistics. Data were compared with results of a cascade model calculation including Lambda Lambda final state interactions consistent with the newly measured binding energy of He6(Lambda Lambda). No significant enhancements above levels of the model predictions were observed. The resulting upper limit for the production cross section of the H with a mass range between the Lambda Lambda and Xi N threshold is found to be 2.1 +/ 0.6 (stat.) +/ 0.1 (syst.) mu b/sr at a 90% confidence level. 
Conference Paper: Study of double hypernuclei with a general scan
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ABSTRACT: Double hypernuclei are important to add the 3rd dimension to the chart of nulei. It is expected that more events of double hypernuclei exist in the emulsion of the KEKPS E373 experiment. We are developing a new method, which is called general scan, in order to find more double hypernuclei. The current status of analysis with a general scan is reported. 
Conference Paper: Hdibaryon search by KEKE522; Search for the ΛΛ resonance in 12C(K −, K +ΛΛX) using a scintillating fiber active target
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ABSTRACT: We searched for the Hdibaryon resonance in the ΛΛ invariant mass spectrum obtained by 12 C(K − , K + ΛΛX) reactions using a scintillating fiber active target. We observed enhanced ΛΛ production near the threshold, as found in a previous KEK experiment, with improved statistics. Data were compared with the results of a cascade model calculation including ΛΛ final state interactions consistent with the recently measured binding energy of the doubleΛ hypernucleus. No significant enhancements above the levels predicted by the model were observed. The upper limit for the production cross section of the Hdibaryon with a mass range between the ΛΛ and ΞN threshold is found to be 2.1 µb/sr at a 90% confidence level. PACS. 14.20.Pt Dibaryon – 25.80.Nv Kaoninduced reactions 
Chapter: Hdibaryon search by KEKE522
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ABSTRACT: We searched for the Hdibaryon resonance in the ΛΛ invariant mass spectrum obtained by 12C(K −, K + ΛΛX) reactions using a scintillating fiber active target. We observed enhanced ΛΛ production near the threshold, as found in a previous KEK experiment, with improved statistics. Data were compared with the results of a cascade model calculation including ΛΛ final state interactions consistent with the recently measured binding energy of the doubleΛ hypernucleus. No significant enhancements above the levels predicted by the model were observed. The upper limit for the production cross section of the Hdibaryon with a mass range between the ΛΛ and ΞN threshold is found to be 2.1 μb/sr at a 90% confidence level.  [Show abstract] [Hide abstract]
ABSTRACT: A search for the Θ+ pentaquark in the K + p → π + X reaction was performed utilizing a highresolution spectrometer at the K6 beam line of the KEK 12GeV Proton Synchrotron. Incident K + beams of 1.2 GeV/c were irradiated to a liquid hydrogen target. No significant evidence of the Θ+ was found. The upper limit of the differential cross section averaged over 2° to 20° in the laboratory frame for the K + p → π +Θ+ reaction was obtained to be 1.9 μb/sr at 90 % confidence level. From the present result, the tchannel process is excluded or the coupling constant gK*NΘ is quite small.  [Show abstract] [Hide abstract]
ABSTRACT: We have searched for Θ via πp→KX reaction using 1.87 and 1.92 GeV/cπ beam at the K2 beam line of the KEK 12 GeV proton synchrotron. In the missing mass spectrum at beam momentum of 1.92 GeV/c, a bump has been found at 1530 MeV/c which is consistent with the mass reported by several experiments. The statistical significance of this bump, however, is only 2.5 2.7σ. Therefore we have derived the upper limit of Θ production cross section via πp→KΘ reaction which is 3.9 μb at 90% confidence level assuming that Θ is produced isotropically in the center of mass system.
Publication Stats
100  Citations  
14.02  Total Impact Points  
Top Journals
Institutions

20062011

Kyoto University
 Department of Physics II
Kioto, Kyōto, Japan


2007

Pusan National University
 Department of Physics
Busan, Busan, South Korea
