Abel, N.
AMY
[58.0]
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Measurement of alpha(s) using NLLA + O (alpha-s**2) in e+ e- annihilation at s**(1/2) = 58-GeV

The AMY collaboration Kim, D.Y. ; Kang, J.S. ; Myung, S.S. ; et al.
Phys.Lett.B 420 (1998) 233-240, 1998.
Inspire Record 455114 DOI 10.17182/hepdata.28221

A measurement of the strong coupling constant α S is presented using hadronic events produced in e + e − annihilations at s =58.0 GeV from the AMY detector at TRISTAN. The measurement is based on comparisons of the distributions of thrust, heavy jet mass, total jet broadening, wide jet broadening, and energy-energy correlations with QCD calculations resummed up to next-to-leading-logarithms matched with the O ( α S 2 ) perturbative calculation. Combining the results of the individual evaluations, we find α S (58 GeV )=0.132±0.006 .

1 data table
Table 1

No description provided.


Measurement of D*+- production in two-photon processes at TRISTAN.

The AMY collaboration Takashimizu, N. ; Sasaki, T. ; Miyata, H. ; et al.
Phys.Lett.B 384 (1996) 96009331 481-486, 1996.
Inspire Record 419685 DOI 10.17182/hepdata.38328

The inclusive cross section for the production of charmed D<sup loc="post">∗±</sup> mesons in two-photon processes is measured with the AMY detector at the TRISTAN e<sup loc="post">+</sup>e<sup loc="post">−</sup> collider. D<sup loc="post">∗±</sup> mesons are identified from the distribution of charged-particle transverse momenta relative to the jet axis. A data sample corresponding to an integrated luminosity of 176 pb<sup loc="post">−1</sup> at a center-of-mass energy of 58 GeV is used to determine a cross section σ(e<sup loc="post">+</sup>e<sup loc="post">−</sup> → e<sup loc="post">+</sup>e<sup loc="post">−</sup>D<sup loc="post">∗±</sup>X) = 270 ± 49(stat) ± 38(syst) pb. The results are compared with theoretical expectations based on the Vector Meson Dominance, direct quark-parton model, and resolved photon processes.

2 data tables
Table 1

No description provided.

Table 2

Reduced acceptance region to compare with the TOPAZ results.


Measurement of charm production in two photon processes using inclusive lepton events at TRISTAN

The AMY collaboration Aso, T. ; Miyata, H. ; Sasaki, T. ; et al.
Phys.Lett.B 363 (1995) 249-258, 1995.
Inspire Record 401053 DOI 10.17182/hepdata.38520

Measurements of open charm production in photon-photon collisions made with the AMY detector at TRISTAN are reported. Charmed hadrons were identified by detecting the high momentum muons or electrons from their semileptonic decays. The data sample corresponds to an integrated luminosity of 275 pb −1 at an average center of mass energy of 58 GeV. Results are presented in the form of cross sections of inclusive leptons from charm for both muons and electrons. The measured cross section is 1.8 standard deviations higher than theoretical predictions based on the direct and photon-gluon fusion process, where the mass of charm quark is assumed to be 1.6 GeV.

3 data tables

Forward - backward charge asymmetry of quark pairs produced at the KEK TRISTAN e+ e- collider

The AMY collaboration Stuart, D. ; Breedon, R.E. ; Chinitz, L.M. ; et al.
Phys.Rev.D 49 (1994) 3098-3105, 1994.
Inspire Record 378569 DOI 10.17182/hepdata.22552

We report on a measurement of the forward-backward charge asymmetry in e+e−→qq¯ at KEK TRISTAN, where the asymmetry is near maximum. We sum over all flavors and measure the asymmetry by determining the charge of the quark jets. In addition we exploit flavor dependencies in the jet charge determination to enhance the contributions of certain flavors. This provides a check on the asymmetries of individual flavors. The measurement agrees with the standard model expectations.

1 data table
Table 1

Forward--backward asymmetry summed over all flavours of quarks.