Measurement of the cross-section and forward-backward charge asymmetry for the b and c quark in e+ e- annihilation with inclusive muons at s**(1/2) = 58-GeV.

The TOPAZ collaboration Inoue, Y. ; Miyamoto, A. ; Nakano, E. ; et al.
Eur.Phys.J.C 18 (2000) 273-282, 2000.
Inspire Record 538542 DOI 10.17182/hepdata.43244

We have studied inclusive muon events using all the data collected by the TOPAZ detector at sqrt(s)=58 GeV with an integrated luminosity of 273pb-1. From 1328 inclusive muon events, we measured the ratio R_qq of the cross section for qq-bar production to the total hadronic cross section and forward-backward asymmetry A^q_FB for b and c quarks. The obtained results are R_bb = 0.13+-0.02(stat)+-0.01(syst), R_cc = 0.36+-0.05(stat)+-0.05(syst), A^b_FB = -0.20+-0.16(stat)+-0.01(syst) and A^c_FB = -0.17+-0.14(stat)+-0.02(syst), in fair agreement with a prediction of the standard model.

3 data tables

Differential cross section with respect to cos(theta).

Cross section deduced from a four-parameter fit.

Forward-backward asymmetry for a four-parameter fit.


Measurement of the jet width in gamma gamma collisions and in e+ e- annihilation process at TRISTAN

The TOPAZ collaboration Adachi, K. ; Hayashii, H. ; Miyabayashi, K. ; et al.
Phys.Lett.B 451 (1999) 256-266, 1999.
Inspire Record 494502 DOI 10.17182/hepdata.43768

The shape of jets produced in (quasi-) real photon-photon collisions as well as in e^+e^- annihilation process has been studied with a cone jet finding algorithm, using the data taken with the TOPAZ detector at the TRISTAN e^+e^- collider at an average center-of-mass energy of 58 GeV. The results are presented in terms of the jet width as a function of the jet transverse energy(E^{jet}_T) as well as a scaled transverse jet energy, x_T(=2E^{jet}_T/root(s)). The jet width narrows as E^{jet}_T increases; however, at the same value of E^{jet}_T the jet width in gamma-gamma collisions at TRISTAN is significantly narrower than that in gamma p collisions at HERA. By comparing our results with the data in other reactions, it has been shown that the jet width in gamma-gamma, gamma p, p\bar{p} collisions as well as the e^+e^- annihilation process has an approximate scaling behavior as a function of x_T.

2 data tables

The jet width is defined as the full width at the half maximum of the distribution of the transverse energy flow.

The jet width is defined as the full width at the half maximum of the distribution of the transverse energy flow.


Charged-particle multiplicities of quark and gluon jets in e+ e- annihilation at TRISTAN.

The TOPAZ collaboration Nakabayashi, K. ; Yamauchi, M. ; Abe, K. ; et al.
Phys.Lett.B 413 (1997) 447-452, 1997.
Inspire Record 454183 DOI 10.17182/hepdata.28238

Charged-particle multiplicity was studied in e + e − annihilation at s = 57.8 GeV using the TOPAZ detector at TRISTAN. The average multiplicity was 〈 n ch 〉 = 17.64± 0.05(stat.) ± 0.41(syst.). It was found that the multiplicity depends on the thrust ( T ) of an event. From extrapolating this relation to T = 2 3 , the multiplicity for three-fold symmetric events was estimated to be 〈n ch 〉 T = 2 3 = 23.50 −1.45 +1.25 . From this, the multiplicity ratio between gluon- and quark-jet was estimated to be r g q = 1.46 −0.13 +0.09 without any possible bias from jet clustering.

4 data tables

No description provided.

Multiplicity measured for events with a Thrust of 2/3. These are three-foldsymmetric events.

Mean charged particle multiplicity as function of -log(1-THRUST).

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A Study of single photon production in e+ e- collisions at s**(1/2) = 58-GeV with the TOPAZ detector at TRISTAN

The TOPAZ collaboration Abe, T. ; Fujii, K. ; Sugiyama, A. ; et al.
Phys.Lett.B 361 (1995) 199-206, 1995.
Inspire Record 406593 DOI 10.17182/hepdata.28440

We report a study of single photon production in e + e − collisions at s =58 GeV with the TOPAZ detector at TRISTAN. From data corresponding to an integrated luminosity of 213 pb −1 , 5 single photon candidates remained after event selection, which can be compared with the expected 3.1 ν ν γ and 2.8 background events. These results exclude the selectron mass below 47.2 GeV at the 90% confidence level, if e ̃ L and e ̃ R are mass-degenerate and the photino is massless. When combined with results from other experiments, this limit improves to 75.0 GeV.

1 data table

No description provided.


Observation of excess lambda (anti-lambda) production in two photon processes at TRISTAN

The TOPAZ collaboration Enomoto, R. ; Abe, K. ; Abe, T. ; et al.
Phys.Lett.B 347 (1995) 179-186, 1995.
Inspire Record 392056 DOI 10.17182/hepdata.38362

We have carried out inclusive measurements of $\Lambda(\overline{\Lambda})$ production in two-photon processes at TRISTAN. The mean $\sqrt{s}$ was 58 GeV and the integrated luminosity was 265 pb$~{-1}$. Inclusive $\Lambda (\overline{\Lambda})$ samples were obtained under such conditions as no-electron, anti-electron, and remnant-jet tags. The data were compared with theoretical calculations. The measured cross sections are two-times larger than the leading-order theoretical predictions, suggesting the necessity of next-to-leading-order Monte-Carlo generator.

9 data tables

No-tag data.

Anti-electron tag data.

Remnant-jet tag with VDM subtraction data.

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Measurement of inclusive particle spectra and test of MLLA prediction in e+ e- annihilation at s**(1/2) = 58-GeV

The TOPAZ collaboration Itoh, R. ; Yamauchi, M. ; Yamaguchi, A. ; et al.
Phys.Lett.B 345 (1995) 335-342, 1995.
Inspire Record 381900 DOI 10.17182/hepdata.38345

Inclusive momentum spectra are measured for all charged particles and for each of $\pi~{\pm}$, $K~{\pm}$, $K~0/\overline{K~0}$, and $p/\overline{p}$ in hadronic events produced via $e~+e~-$ annihilation at $\sqrt{s}$=58GeV . The measured spectra are compared with QCD predictions based on the modified leading log approximation(MLLA). The MLLA model reproduces the measured spectra well. The energy dependence of the peak positions of the spectra is studied by comparing the measurements with those at other energies. The energy dependence is also well described by the MLLA model.

3 data tables

Errors include both statistical and systematic errors.

Errors include both statistical and systematic errors.

Statistical errors only.


Measurement of the forward - backward asymmetries for charm and bottom quark pair productions at S**(1/2) = 58-GeV with electron tagging

The TOPAZ collaboration Nakano, E. ; Enomoto, R. ; Iwasaki, M. ; et al.
Phys.Lett.B 340 (1994) 135-142, 1994.
Inspire Record 39496 DOI 10.17182/hepdata.28532

We have measured, with electron tagging, the forward-backward asymmetries of charm- and bottom-quark pair productions at $\langle \sqrt{s} \rangle$=58.01GeV, based on 23,783 hadronic events selected from a data sample of 197pb$~{-1}$ taken with the TOPAZ detector at TRISTAN. The measured forward-backward asymmetries are $A_{FB}~c = -0.49 \pm 0.20(stat.) \pm 0.08 (sys.)$ and $A_{FB}~b = -0.64 \pm 0.35(stat.) \pm 0.13 (sys.)$, which are consistent with the standard model predictions.

1 data table

No description provided.


Measurement of the total hadronic cross-section and determination of gamma - Z interference in e+ e- annihilation

The TOPAZ collaboration Miyabayashi, K. ; Adachi, I. ; Fujii, K. ; et al.
Phys.Lett.B 347 (1995) 171-178, 1995.
Inspire Record 381777 DOI 10.17182/hepdata.38368

The total hadronic cross section in e + e − annihilation was measured at s =5.77 GeV to be σ h = 143.6 ± 1.5 (stat) ± 3.5 (sys) pb with only the QED corrections. The measurement was based on data corresponding to an integrated luminosity of 90.8 pb −1 accumulated by the TOPAZ detector at TRISTAN. Our data point put stringent constraints on the size of the γ - Z 0 interference and the Z 0 mass. Combining our data with the OPAL data at LEP, we obtained the coefficient of the interference and the Z 0 mass to be J had = 0.10 ± 0.26 and M z = 91.151 ± 0.008 GeV, respectively, in a model-independent analysis.

1 data table

Total hadronic cross section after QED corrections.


Measurement of inclusive electron cross-section in gamma gamma collisions at TRISTAN

The TOPAZ collaboration Iwasaki, M. ; Enomoto, R. ; Hayashii, H. ; et al.
Phys.Lett.B 341 (1994) 99-108, 1994.
Inspire Record 378075 DOI 10.17182/hepdata.43778

We have studied open charm production in $\gamma \gamma$ collisions with the TOPAZ detector at the TRISTAN $e~{+}e~{-}$ collider. In this study, charm quarks were identified by electrons (and positrons) from semi-leptonic decays of charmed hadrons. The data corresponded to an integrated luminosity of 95.3 pb$~{-1}$ at a center-of-mass energy of 58 GeV. The results are presented as the cross sections of inclusive electron production in $\gamma \gamma$ collisions with an anti-tag condition, as well as the subprocess cross sections, which correspond to resolved-photon processes. The latter were measured by using a sub-sample with remnant jets. A comparison with various theoretical predictions based on direct and resolved-photon processes showed that our data prefer that with relatively large gluon contents in a photon at small $x (x \le 0.1)$, with the next-to-leading order correction, and with a charm-quark mass of 1.3 GeV.

2 data tables

The description of events with anti-tag, remnant-jet-tag, and no-tag are presnted in text.


K0 (anti-K0) production in two photon processes at TRISTAN

The TOPAZ collaboration Enomoto, R. ; Abe, K. ; Abe, T. ; et al.
Phys.Lett.B 341 (1994) 238-244, 1994.
Inspire Record 377805 DOI 10.17182/hepdata.38385

We have carried out an inclusive measurement of $K~0(\overline{K~0})$ production in two-photon processes at TRISTAN. The mean $\sqrt{s}$ was 58 GeV and the integrated luminosity was 199 pb$~{-1}$. High-statistics $K_s$ samples were obtained under such conditions as no-, anti-electron, and remnant-jet tags. The remnant-jet tag, in particular, allowed us, for the first time, to measure the cross sections separately for the resolved-photon and direct processes.

6 data tables

No tag data.

Anti-electron tag data.

Remnant-jet tag with VDM subtraction data.

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