HEPData Search

Showing 10 of 32 results

rivet Analysis
Inclusive production of pi0, eta, eta'(958), K0(S) and Lambda in two- and three-jet events from hadronic Z decays.

The ALEPH collaboration Barate, R. ; Decamp, D. ; Ghez, Philippe ; et al.

Eur.Phys.J.C 16 (2000) 613, 2000.

Inspire Record 507531 DOI 10.17182/hepdata.49106

The production rates and the inclusive cross sections of the isovector meson${\rm \pi^0}$, the isoscalar mesons$\eta$and

25 data tables

Table 1

Inclusive cross section for PI0 production in hadronic events.

Table 2

Inclusive cross section for ETA production in hadronic events.

Table 3

Inclusive cross section for ETAPRIME production in hadronic events.

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Measurement of the fraction of hadronic Z decays into charm quark pairs.

The ALEPH collaboration Barate, R. ; Buskulic, D. ; Decamp, D. ; et al.

Eur.Phys.J.C 4 (1998) 557-570, 1998.

Inspire Record 468852 DOI 10.17182/hepdata.49530

The full statistics of hadronic Z decays collected with the ALEPH detector are analysed to measure, by three methods, the ratio, ${\rm R_c}$ , of the partial decay

1 data table

Table 1

No description provided.

rivet Analysis
Measurement of the total cross section for e+ e- --> hadrons at s**(1/2) = 10.52-GeV.

The CLEO collaboration Ammar, R. ; Baringer, Philip S. ; Bean, A. ; et al.

Phys.Rev.D 57 (1998) 1350-1358, 1998.

Inspire Record 445351 DOI 10.17182/hepdata.47132

Using the CLEO detector at the Cornell Electron Storage Ring, we have made a measurement of R=sigma(e+e- ->hadrons)/sigma(e+e- ->mu+mu-) =3.56+/-0.01+/-0.07 at ECM=10.52 GeV. This implies a value for the strong coupling constant of alpha_s(10.52 GeV)=0.20+/-0.01+/-0.06, or alpha_s(M_Z)=0.13+/-0.005+/-0.03.

2 data tables

Table 1

Corrected for background and radiactive effects.

Table 2

Value of ALPHAS, the strong coupling constant, from the measurement of R. CT,= ALPHAS also given evolved to the Z0 mass.

rivet Analysis
Inclusive production of neutral pions in hadronic Z decays.

The ALEPH collaboration Barate, R. ; Buskulic, D. ; Decamp, D. ; et al.

Z.Phys.C 74 (1997) 451-461, 1997.

Inspire Record 427131 DOI 10.17182/hepdata.47655

A measurement of the inclusive production of π0 mesons in hadronic Z decays is presented and compared to Monte Carlo model predictions. The analysis is based on approximately 2 million hadronic events recorded with the ALEPH detector at LEP at a centre-of-mass energy of ⊡s = 91.2 GeV. Neutral pions are reconstructed using photons measured in the electromagnetic calorimeter and photons from conversion pairs. The inclusive π0 momentum spectrum is measured in the range 0.025 < xp = p/pbeam < 1. In this range the number of π0 per hadronic Z is found to be 4.80 ± 0.07(stat) ± 0.31(sys). The differential inclusive π0 cross section is also measured as a function of transverse momentum with respect to the event plane (pTin and pTout).

4 data tables

Table 1

PI0 multiplicity and cross sections for events with two converted photons.

Table 2

PI0 multiplicity and cross sections for events with only one converted photon. Final data point for full x range uses jetset 7.4 monte carlo extrapolation prediction.

Table 3

PI0 cross sections as a function of the transverse momentum PTOUT relative to the plane defined by the sphericity tensor.

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Measurement of hadron and lepton pair production from e+ e- annihilation at center-of-mass energies of 130-GeV and 136-GeV

The ALEPH collaboration Buskulic, D. ; De Bonis, I. ; Decamp, D. ; et al.

Phys.Lett.B 378 (1996) 373-384, 1996.

Inspire Record 421552 DOI 10.17182/hepdata.47801

Hadronic and leptonic cross-sections and forward-backward asymmetries are measured using 5.7 pb −1 of data taken with the ALEPH detector at LEP at centre-of-mass energies of 130 and 136 GeV. The results agree with Standard Model expectations. The measurement of hadronic cross-sections far away from the Z resonance improves the determination of the interference between photon and Z exchange. Constraints on models with extra Z bosons are presented.

12 data tables

Table 1

Data with loose SPRIME cut.

Table 2

Data with tight SPRIME cut.

Table 3

Data with loose SPRIME cut.

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Determination of sin**2 theta(w)(eff) using jet charge measurements in hadronic Z decays

The ALEPH collaboration Buskulic, D. ; De Bonis, I. ; Decamp, D. ; et al.

Z.Phys.C 71 (1996) 357-378, 1996.

Inspire Record 416137 DOI 10.17182/hepdata.47832

None

1 data table

Table 1

The first sytematic error is due to the experimental uncertainties, whilst the second is due to the uncertainties in the quark charge separations.

rivet Analysis
Inclusive pi+-, K+- and (p, anti-p) differential cross-sections at the Z resonance

The ALEPH collaboration Buskulic, D. ; Casper, D. ; De Bonis, I. ; et al.

Z.Phys.C 66 (1995) 355-366, 1995.

Inspire Record 382179 DOI 10.17182/hepdata.48315

Inclusive π±, K± and$(p,\bar p)$ differential cross-sections in hadronic decays of the Z have been measured as a function ofz=Phadron/Pbeam, the scaled momentum. The results are based on approximately 520 000 events measured by the ALEPH detector at LEP during 1992. Charged particles are identified by their rate of ionization energy loss in the ALEPH Time Projection Chamber. The position, ξ*, of the peak in the ln(1/z) distribution is determined, and the evolution of the peak position with centre-of-mass energy is compared with the prediction of QCD.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

rivet Analysis
Measurement of alpha-s (M(Z)**2) from hadronic event observables at the Z0 resonance

The SLD collaboration Abe, K. ; Abt, I. ; Ahn, C.J. ; et al.

Phys.Rev.D 51 (1995) 962-984, 1995.

Inspire Record 378545 DOI 10.17182/hepdata.22450

The strong coupling alpha_s(M_Z^2) has been measured using hadronic decays of Z^0 bosons collected by the SLD experiment at SLAC. The data were compared with QCD predictions both at fixed order, O(alpha_s^2), and including resummed analytic formulae based on the next-to-leading logarithm approximation. In this comprehensive analysis we studied event shapes, jet rates, particle correlations, and angular energy flow, and checked the consistency between alpha_s(M_Z^2) values extracted from these different measures. Combining all results we obtain alpha_s(M_Z^2) = 0.1200 \pm 0.0025(exp.) \pm 0.0078(theor.), where the dominant uncertainty is from uncalculated higher order contributions.

16 data tables

Table 1

Final average value of alpha_s. The second (DSYS) error is from the uncertainty on the theoretical part of the calculation.

Table 2

TAU is 1-THRUST.

Table 3

RHO is the normalized heavy jet mass MH**2/EVIS**2.

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Measurement of alpha-s from energy-energy correlations at the Z0 resonance

The SLD collaboration Abe, K. ; Abt, I. ; Ash, W.W. ; et al.

Phys.Rev.D 50 (1994) 5580-5590, 1994.

Inspire Record 373005 DOI 10.17182/hepdata.17744

We have determined the strong coupling $\as$ from a comprehensive study of energy-energy correlations ($EEC$) and their asymmetry ($AEEC$) in hadronic decays of $Z~0$ bosons collected by the SLD experiment at SLAC. The data were compared with all four available predictions of QCD calculated up to $\Oa2$ in perturbation theory, and also with a resummed calculation matched to all four of these calculations. We find large discrepancies between $\as$ values extracted from the different $\Oa2$ calculations. We also find a large renormalization scale ambiguity in $\as$ determined from the $EEC$ using the $\Oa2$ calculations; this ambiguity is reduced in the case of the $AEEC$, and is very small when the matched calculations are used. Averaging over all calculations, and over the $EEC$ and $AEEC$ results, we obtain $\asz=0.124~{+0.003}_{-0.004} (exp.) \pm 0.009 (theory).$

5 data tables

Table 1

Statistical errors only.

Table 2

Statistical errors only.

Table 3

ALPHAS from the EEC O(ALPHAS**2) measurement.