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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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

No description provided.

No description provided.

No description provided.

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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

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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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

Numerical values supplied by R. Enomoto.

No description provided.


Measurement of the forward - backward asymmetry of e+ e- ---> c anti-c at s**(1/2) = 57.95-GeV

The TOPAZ collaboration Nakano, E. ; Enomoto, R. ; Abe, K. ; et al.
Phys.Lett.B 314 (1993) 471-476, 1993.
Inspire Record 361662 DOI 10.17182/hepdata.28846

Measurements of the forward-backward asymmetry of e + e − → cc events were carried out at a mean √s energy of 57.95 GeV at TRISTAN, KEK. The cc events were tagged either by the full-reconstruction of D ∗± or the inclusive P T spectrum of π s ± from D ∗± → D 0 ( D 0 )π s ± . The forward-backward asymmetry was measured to be A FB c = −0.49 −0.13 +0.14 (stat.) ± 0.06 (syst.), consistent with the standard model.

1 data table

No description provided.


Measurements of alpha-s in e+ e- annihilation at TRISTAN

The TOPAZ collaboration Ohnishi, Y. ; Adachi, I. ; Fujimoto, J. ; et al.
Phys.Lett.B 313 (1993) 475-482, 1993.
Inspire Record 361661 DOI 10.17182/hepdata.43784

The strong coupling constant α s was determined from analyses of the thrust, heavy jet mass and, differential 2-jet rate, using e + e - hadronic events at s = 58 GeV with the TOPAZ detector at TRISTAN. The NLLjet Monte Carlo simulation (NLLjet) and analytic formulae based on resummation up to the next-to-leading logarithms combined with O ( α 2 s ) calculations were used to evaluate α s . The average α s values at Q 2 = (58 GeV) 2 from the analyses are α s = 0.125 ± 0.009 for NLLjet and α s = 0.132 ± 0.008 for the resummed analytic formulae.

4 data tables

No description provided.

No description provided.

The exact definition for Y23 see text.

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Measurement of the inclusive cross-section of jets in $\gamma \gamma$ interactions at TRISTAN

The TOPAZ collaboration Hayashii, H. ; Miyamoto, A. ; Iwasaki, M. ; et al.
Phys.Lett.B 314 (1993) 149-158, 1993.
Inspire Record 355918 DOI 10.17182/hepdata.28845

We have investigated the properties of jet production in almost real γγ collisions at √ s =58 GeV with the TOPAZ detector at the TRISTAN e + e − collider. The data were analyzed with a jet-clustering method based on a cone algorithm. The jet rate shows evidence for a hard scattering effect of the hadronic constituents of a photon (resolved photon processes). We have also observed a substantial energy flow in the small-angle region, which is additional evidence for resolved photon processes. We present the transverse momentum dependence of the inclusive jet and two-jet cross sections and compare them with different model predictions.

3 data tables

No description provided.

No description provided.

No description provided.


Search for a narrow resonance in e+ e- collisions between E(cm) = 58-GeV and 60-GeV

The TOPAZ collaboration Abe, K. ; Adachi, I. ; Awa, S. ; et al.
Phys.Lett.B 304 (1993) 373-380, 1993.
Inspire Record 353845 DOI 10.17182/hepdata.28918

We carried out the energy scan between E CM = 58 and 60 GeV at the TRISTAN e + e − collider to search for the possible narrow resonance suggested by the L3 experiment at LEP. The total cross sections are measured for γγ, multihadron, e + e − and μ + μ − production at ten energy points covering this energy range almost uniformly. The results are in good agreement with the Standard Model predictions, and 95% confidence level upper limits are set to Γ ee × BR of the hypothetical scalar and tensor resonances.

4 data tables

No description provided.

No description provided.

No description provided.

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Cross-sections and charge asymmetries for e+ e- ---> mu+ mu- and e+ e- ---> tau+ tau- reactions at s**(1/2) = 52-GeV - 61.4-GeV

The TOPAZ collaboration Howell, B. ; Koltick, D.S. ; Tauchi, T. ; et al.
Phys.Lett.B 291 (1992) 206-212, 1992.
Inspire Record 336076 DOI 10.17182/hepdata.29061

The process e + e − → μ + μ − and e + e − have been studied in the energy range s =52−61.4 GeV , using the TOPAZ detector at TRISTAN. From an integrated luminosity of L = 74.0 pb −1 , lowest-order cross sections and forward-backward asymmetries are measured to be 〈σ μμ 〈 = 25.4±0.9±1.2 pb , 〈A μμ 〉 = (−32.2±3.1±1.1)%, 〈σ ττ 〉 = 27.1±1.1±1.2 pb , 〈A ττ 〉 = (−33.9±4.9±1.0)% , at an average energy of s 〉=57.87 GeV . From the measured assymetry we derive axial vector couplings of a c a μ =0.96±0.09±0.01,and a c a τ =1.01±0.14±0.01±. These results are consistent with standard model expectations. Lower limits in the range 2–5 TeV (95%CL)are placed on compositeness scale parameters for leptons.

6 data tables

No description provided.

Additional 4.6 pct systematic uncertainty.

Additional 4.4 pct systematic uncertainty.

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An experimental study of muon pair production in tagged two photon interactions

The TOPAZ collaboration Hayashii, H. ; Nishioka, H. ; Abe, T. ; et al.
Phys.Lett.B 279 (1992) 422-428, 1992.
Inspire Record 332576 DOI 10.17182/hepdata.29228

The process e + e − →e + e − μ + μ − has been studied in single-tag and double-tag configurations using the TOPAZ detector at TRISTAN. The data correspond to the integrated luminosity of 45.3pb − at center-of-mass energies ranging from 52 to 61.4 GeV. The observed events in both configurations have shown a good agreement with QED predictions in order α 4 . Although the AMY group reported an excess of e + e − →e + e − μ + μ − events in double-tag mode at low muon invariant mass region less than 1.0 GeV/c 2 , we did not observed such excess in our data.

1 data table

No description provided.


Experimental study of b quark jets in e+ e- annihilation at TRISTAN

The TOPAZ collaboration Nagai, K. ; Enomoto, R. ; Abe, T. ; et al.
Phys.Lett.B 278 (1992) 506-510, 1992.
Inspire Record 333342 DOI 10.17182/hepdata.29230

An experimental study of b-quark jets using high- p T electrons was carried out at √ s =58 GeV with the TOPAZ detector at the e + e − collider TRISTAN at KEK. The forward-backward charge asymmetry of the b-quark was obtained to be A b b ̄ =−0.55±0.27( stat. )±0.07( syst. ) , consistent with the standard model prediction. Also, such jet properties of the b-quark as the average charged multiplicity and the rapidity of charged particles were analyzed. In order to purify the b-quark event samples in this analysis, only events with backward-going electrons or forward-going positrons were used. The energy dependence of these jet properties was studied by making comparisons with the results of the DELCO experiment at the PEP collider (√ s =29 GeV) at SLAC.

4 data tables

No description provided.

No description provided.

Mean values of jet properties for b-jet sample.

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Studies of e+ e- ---> gamma gamma and gamma-gamma-gamma reactions

The TOPAZ collaboration Shimozawa, K. ; Fujimoto, J. ; Abe, T. ; et al.
Phys.Lett.B 284 (1992) 144-150, 1992.
Inspire Record 339575 DOI 10.17182/hepdata.29177

We have measured the cross section for γγ production with the TOPAZ detector in the energy region √ s =50.0–61.4 GeV. The observed cross section for γγ production integrated over |cos θ | ⩽ 0.77 is 50.2±0.8±2.2 pb at 〈√ s 〉=57.6 GeV and the ratio of this value to the QED prediction is 1.01±0.02±0.04. The angular distribution is in good agreement with the QED predictions, thereby setting limits on the compositeness scales, Λ L+R + =168 GeV, Λ L+R − =97 GeV, Λ L,R =141 GeV, Λ L,R − =81 GeV, and Λ L−R ± =68 GeV, at the 95% confidence level. The reaction e + e − → γγγ was also studied and was found consistent with the QED prediction.

11 data tables

No description provided.

No description provided.

No description provided.

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Measurements of b quark forward - backward charge asymmetry and axial vector coupling using inclusive muons in e+ e- annihilation at s**(1/2) = 52-GeV - 61.4-Gev

The TOPAZ collaboration Shimonaka, A. ; Fujii, K. ; Miyamoto, A. ; et al.
Phys.Lett.B 268 (1991) 457-464, 1991.
Inspire Record 319034 DOI 10.17182/hepdata.29343

We have collected 122 multi-hadronic inclusive muon events with the TOPAZ detector at 〈 s 〉 = 58.27 GeV with ∫ L d t=40.61 pb −1 . From this event sample we derived the differential cross section for B-hadron productions and determined B-hadron forward-backward asymmetry (A b b ) to be A b b = −0.71 ± 0.34 ( stat ) +0.07 −0.08 ( syst ) . A fit to the differential cross section, after correcting for the effect of B 0 B 0 mixing, yielded the axial-vector coupling constant of the b-quark ( a b ): a b = −1.79 +0.34 −0.32 (stat) +0.15 −0.14 (syst). We also set a 90% confidence level limit of χ <0.37 on the B 0 B 0 mixing parameter.

4 data tables

Observed differential cross section.

No description provided.

No description provided.

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Charge asymmetry of hadronic events in $e^{+} e^{-}$ annihilation at $\sqrt{s}$ = 57.9-GeV

The TOPAZ collaboration Adachi, I. ; Anazawa, M. ; Doser, M. ; et al.
Phys.Lett.B 255 (1991) 613-622, 1991.
Inspire Record 314203 DOI 10.17182/hepdata.29492

The charge asymmetry of quark jets produced in e + e − annihilations at 〈√ s 〉=57.9 GeV was measured with the TOPAZ detector at TRISTAN. The observed charge asymmetry is +0.091±0.014(stat.)±0.016(sys.). From the measured differential cross section, the axial vector coupling constant averaged over all quark flavors was determined to be 1.09 −0.21 +0.27 . These values are consistent with the standard model predictions. Possible deviations from the standard model were examined in terms of contact interactions, and the lower limits on the compositeness scale parameters were obtained to be 1.2–7.1 TeV at the 95% confidence level.

2 data tables

No description provided.

No description provided.


Measurement of the Total Hadronic Cross-sections in e$^{+} $e$^{-}$ Annihilation and Determination of the Standard Model Parameters

The TOPAZ collaboration Adachi, I. ; Doser, M. ; Enomoto, R. ; et al.
Phys.Lett.B 234 (1990) 525-533, 1990.
Inspire Record 283003 DOI 10.17182/hepdata.29733

We have measured the total e + e − hadronic annihilation cross section at the center of mass energies between 50.0 GeV and 61.4 GeV with the TOPAZ detector at TRISTAN. The full electroweak radiative corrections (up to O(α 3 )) were applied to the data which were analysed together with the published data from PEP and PETRA. We then determined the standard model parameters, M z (the mass of the Z), sin w 2 θ (the Weinberg angle) and Λ MS (the QCD scale parameter) by comparing the experimental data with the prediction of the standard model. The best fit values are M z = 89.2 −1.8 +2.1 GeV/c 2 , sin 2 θ w = 0.233 −0.025 +0.035 and Λ MS = 0.327 −0.206 +0.275 GeV. A constraint is obtained on the heavy top quark mass through the radiative corrections if we take the SLC value of M z (91.1 GeV / c 2 ).

2 data tables

No description provided.

No description provided.


Measurements of $\alpha^- s$ in $e^+ e^-$ Annihilation at $\sqrt{s}=53$.3-{GeV} and 59.5-{GeV}

The TOPAZ collaboration Adachi, I. ; Aihara, H. ; Doser, M. ; et al.
Phys.Lett.B 227 (1989) 495-500, 1989.
Inspire Record 279575 DOI 10.17182/hepdata.29800

We studied the energy-energy correlation (EEC) and its asymmetry (AEEC) using e + e − hadronic annihilation events obtained at √ s =53.3 GeV and 59.5 GeV with the TOPAZ detector at the TRISTAN collider. We used a Monte Carlo simulation combined with the QCD matrix elements by Gottschalk and Shatz and the Lund string fragmentation model. By comparing the experimental data with simulated events, we determined the strong coupling constant α s at both energies. The results are 0.129±0.007 (stat) ±0.010 (syst) at √ s =53.3 GeV and 0.122±0.008 (stat) ±0.010 (syst) at 59.5 GeV.

2 data tables

No description provided.

No description provided.