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Search for Top Quark in e+ e- Collisions at s**(1/2) = 52-GeV

The TOPAZ collaboration Adachi, I. ; Aihara, H. ; Dijkstra, H.B. ; et al.
Phys.Rev.Lett. 60 (1988) 97, 1988.
Inspire Record 251830 DOI 10.17182/hepdata.20141

We searched for possible signatures of top-quark production in 508 e+e− hadronic annihilation events collected at s=52 GeV by the TOPAZ detector at the KEK e+e− collider TRISTAN. The observed hadronic cross section and shape of hadronic events are consistent with the standard-model predictions without top quarks. A lower limit (95% confidence level) on the mass of the lightest top meson is set at 25.8 GeV.

1 data table match query

No description provided.


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 match query

Errors include both statistical and systematic errors.

Errors include both statistical and systematic errors.

Statistical errors only.


Measurement of the D*+- cross-section using a soft pion analysis in two photon processes

The TOPAZ collaboration Enomoto, R. ; Abe, K. ; Abe, T. ; et al.
Phys.Lett.B 328 (1994) 535-546, 1994.
Inspire Record 372139 DOI 10.17182/hepdata.38387

The differential cross section of $d\sigma(e~+e~-\rightarrow e~+e~-D~{*\pm}X)/dP_T$ was measured using a soft-pion analysis of $D~{*\pm}\rightarrow \pi_s~\pm D~0(\overline{D~0})$ at TRISTAN. The average $\sqrt{s}$ was 58.1 GeV and the integrated luminosity used in this analysis was 198 pb$~{-1}$, respectively.

4 data tables match query

Soft pion cross section.

D*+- cross section from the soft-pion analysis.

Previous `full reconstruction' measurement from Enomoto et al. (to be published).

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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 match query

No tag data.

Anti-electron tag data.

Remnant-jet tag with VDM subtraction data.

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Measurement of the photon structure function F2(gamma) and jet production at TRISTAN

The TOPAZ collaboration Muramatsu, K. ; Hayashii, H. ; Noguchi, S. ; et al.
Phys.Lett.B 332 (1994) 477-487, 1994.
Inspire Record 373856 DOI 10.17182/hepdata.38377

We have measured the photon structure function F 2 γ in the reaction e + e − → e + e − hadrons for average Q 2 values from 5.1 to 338 GeV 2 by using data collected by the TOPAZ detector at TRISTAN. The data have been corrected for detector effects and are compared with theoretical expectations based on QCD. The structure function F 2 γ increases as ln Q 2 , as expected. A sample of events with one or two distinct jets has been identified in the final state. Although two-jet events can be explained solely by the point-like perturbative part, one-jet events require a significant hadron-like part in addition.

7 data tables match query

No description provided.

No description provided.

No description provided.

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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 match query

Differential cross section with respect to cos(theta).

Cross section deduced from a four-parameter fit.

Forward-backward asymmetry for a four-parameter fit.


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 match query

No-tag data.

Anti-electron tag data.

Remnant-jet tag with VDM subtraction data.

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Measurement of the D*+- cross-section in a two photon process

The TOPAZ collaboration Enomoto, R. ; Iwasaki, M. ; Muramatsu, K. ; et al.
Phys.Rev.D 50 (1994) 1879-1883, 1994.
Inspire Record 357776 DOI 10.17182/hepdata.38389

We have measured the inclusive $D~{*\pm}$ production cross section in a two-photon collision at the TRISTAN $e~+e~-$ collider. The mean $\sqrt{s}$ of the collider was 57.16 GeV and the integrated luminosity was 150 $pb~{-1}$. The differential cross section ($d\sigma(D~{*\pm})/dP_T$) was obtained in the $P_T$ range between 1.6 and 6.6 GeV and compared with theoretical predictions, such as those involving direct and resolved photon processes.

2 data tables match query

Numerical values supplied by R. Enomoto.

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 match query

Total hadronic cross section after QED corrections.


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 match query

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.