Publications (8)0 Total impact
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Article: Study of inclusive baryon-antibaryon pair production of p or Λ in two-photon processes
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ABSTRACT: Inclusive baryon-antibaryon pair production was studied in two-photon events which were collected at thee + e − collider TRISTAN, and correspond to an integrated luminosity of 303 pb−1. Correlations between a baryon and an antibaryon were studied for their flavors (p orΛ) and their momentum vectors. The experimental results were compared with the expectations from a jet-fragmentation Monte Carlo simulation. We have found that although the ratios of the cross sections of different baryon-flavor combinations are consistent with the Monte Carlo expectations, the cross section shows an excess over the Monte Carlo expectation in a low invariant-mass region of final-state particles at large angles, that indicates a significant contribution from higher-order QCD or non-perturbative effects. The experimental data show no narrow azimuthal-angle correlation, which is expected from a jet-fragmentation Monte Carlo. A search for exclusiveΛ pair production has also been made. We have no candidates and have obtained the upper limit for the cross section.Zeitschrift für Physik C 11/1995; 69(1):597-606. -
Article: Measurement of open charm production in two-photon processes with detection of electron-inclusive events
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ABSTRACT: Experimental studies of open charm production in two-photon processes have been performed. In the measurement, charmed hadrons were identified by electrons from their semi-leptonic decays. The result was compared with calculations based on the direct process and photon-gluon fusion process by resolved photons. We found that the effect of the gluon component in a photon is substantial in the observed events.Zeitschrift für Physik C 05/1994; 63(2):213-218. -
Article: Measurement of forward-backward charge asymmetry in the process of b-quark production in e+e− annihilation around √s=60 GeV
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ABSTRACT: We have measured the forward-backward charge asymmetry in the process of b-quark production in e+e− annihilation at TRISTAN. It was made possible by detecting prompt leptons from b-quarks. The obtained asymmetry is A= −0.55±0.15±0.08. If corrected for B-meson mixing effects with the assumptions given in the text, the asymmetry becomes A=f−0.78±0.21±0.11, which is consistent with the prediction of the standard model, namely the assignment of the b-quark to the isospin doublet of the third quark generation.Physics Letters B. -
Article: Study of inclusive baryon-antibaryon pair production of p or $\Lambda$ in two-photon processes
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Article: Study of $\pi^{+}\pi^{-}$ pair production in a two-photon process at TRISTAN
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Article: Determination of the QCD scale parameter ΛMS with QCD cascade on the basis of the next-to-leading logarithmic approximation
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ABSTRACT: The relative production ratio of 3-jet events to the total number of hadronic events was studied in e+e− annihilations at centre-of-mass energies between 54 and 61.4 GeV. The QCD scale parameter has been determined to be on the basis of a QCD cascade with the next-to-leading logarithmic approximation.Physics Letters B. -
Article: Search for charged scalars in e+e− annihilation up to 64 GeV CM energy
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ABSTRACT: A search for the production of charged scalars has been carried out in e+e− annihilation at center of mass energies up to 64 GeV with 61.1 pb−1 of integrated luminosity using the VENUS detector at TRISTAN. The assumptions concerning the production and decay of hypothetical charged scalars are minimal; they are expected to be singly charged and decay into a pair of fermions. No positive evidence for their production has been found in a study of all combinations of the and ) decay channels. We have excluded the mass region of 8.0–20.0 GeV/c2 regardless of the decay mode.Physics Letters B. 267(2):309-316. -
Article: A study of charged D∗ production in e+e− annihilation at an average center-of-mass energy of 58 GeV
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ABSTRACT: We have studied the production of charged D∗ mesons in e+e− annihilation at an average center-of-mass energy of 58.0 GeV. Charged D∗ mesons were identified using two independent methods; the mass-difference method and the detection of the low transverse-momentum pion. The forward-backward asymmetry of the charm quark production was measured to be Ac= −0.61±0.13(stat.)±0.08(syst.). The cross section of inclusive D∗ production was found to be pb. If we assume the standard model prediction for the charm quark production, we obtain the branching ratio for the charm quark to produce a charged D∗ meson to be .Physics Letters B.
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1994
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University of Tsukuba
- Applied Physics
Tsukuba, Ibaraki-ken, Japan
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