HEPData Search

Showing 10 of 21 results

A Determination of alpha-s (M (Z0)) at LEP using resummed QCD calculations

The OPAL collaboration Acton, P.D. ; Alexander, G. ; Allison, John ; et al.

Z.Phys.C 59 (1993) 1-20, 1993.

Inspire Record 354188 DOI 10.17182/hepdata.14427

The strong coupling constant, αs, has been determined in hadronic decays of theZ0 resonance, using measurements of seven observables relating to global event shapes, energy correlatio

7 data tables match query

Table 1

Data corrected for finite acceptance and resolution of the detector and for intial state photon radiation. No corrections for hadronic effects are applied.. Errors include statistical and systematic uncertainties, added in quadrature.

Table 2

Table 3

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A Global determination of alpha-s (M(z0)) at LEP

The OPAL collaboration Acton, P.D. ; Alexander, G. ; Allison, John ; et al.

Z.Phys.C 55 (1992) 1-24, 1992.

Inspire Record 333079 DOI 10.17182/hepdata.14606

The value of the strong coupling constant,$$\alpha _s (M_{Z^0 } )$$, is determined from a study of 15 d

16 data tables match query

Table 1

Differential jet mass distribution for the heavier jet using method T. The data are corrected for the finite acceptance and resolution of the detector and for initial state photon radiation.

Table 2

Differential jet mass distribution for the jet mass difference using methodT. The data are corrected for the finite acceptance and resolution of the detec tor and for initial state photon radiation.

Table 3

Differential jet mass distribution for the heavier jet using method M. The data are corrected for the finite acceptance and resolution of the detector and for initial state photon radiation.

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rivet Analysis
A Measurement of D meson production in Z0 hadronic decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.

Z.Phys.C 59 (1993) 533-546, 1993.

Inspire Record 356732 DOI 10.17182/hepdata.14375

A study of the fragmentation properties of charm and bottom quarks intoD mesons is presented. From 263 700Z0 hadronic decays collected in 1991 with the DELPHI detector at the LEP collider,D0,D+ andD*+ are reconstructed in the modesK−π+,K−π+K+ andD0π+ followed byD0→K−π+, respectively. The fractional decay widths$\Gamma {{(Z^0\to {D \mathord{\left/ {\vphantom {D {\bar D}}} \right. \kern-\nulldelimiterspace} {\bar D}}X)} \mathord{\left/ {\vphantom {{(Z^0\to {D \mathord{\left/ {\vphantom {D {\bar D}}} \right. \kern-\nulldelimiterspace} {\bar D}}X)} {\Gamma _h }}} \right. \kern-\nulldelimiterspace} {\Gamma _h }}$ are determined, and first results are presented for the production ofD mesons from$c\bar c$ and$b\bar b$ events separately. The average energy fraction ofD*± in charm quark fragmentation is found to be 〈XE(D*)〉c=0.487±0.015 (stat)±0.005 (sys.). Assuming that the fraction ofDs and charm-baryons produced at LEP is similar to that around 10 GeV, theZ0 partial width into charm quark pairs is determined to beΓc/Γh=0.187±0.031 (stat)±0.023 (sys). The probability for ab quark to fragment into$\bar B_s $ orb-baryons is inferred to be 0.268±0.094 (stat)±0.100 (sys) from the measured probability that it fragments into a$\bar B^0 $ orB−.

6 data tables match query

Table 1

Using full data sample.

Table 2

Using full data sample with proper time > 1 ps to enrich (b bbar) content.

Table 3

Data with Delta(L) > 1.

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Analysis of hadronic final states and the photon structure function F2(gamma) in deep inelastic electron photon scattering at LEP.

The OPAL collaboration Ackerstaff, K. ; Alexander, G. ; Allison, John ; et al.

Z.Phys.C 74 (1997) 33-48, 1997.

Inspire Record 426209 DOI 10.17182/hepdata.47770

Deep inelastic electron-photon scattering is studied in the Q2 ranges from 6 to 30 GeV2 and from 60 to 400 GeV2 using the full sample of LEP data taken with the OPAL detector at centre-of-mass energies close to the Z0 mass, with an integrated luminosity of 156.4 pb−1. Energy flow distributions and other properties of the measured hadronic final state are compared with the predictions of Monte Carlo models, including HERWIG and PYTHIA. Sizeable differences are found between the data and the models, especially at low values of the scaling variable x. New measurements are presented of the photon structure function $F_2^{αmma }(x,Q^2)$, allowing for the first time for uncertainties in the description of the final state by different Monte Carlo models. The differences between the data and the models contribute significantly to the systematic errors on $F_2^{αmma }$. The slope ${⤪ d}(F_2^{αmma }/←pha )/{⤪ d ln} Q^2$ is measured to be $0.13_{-0.04}^{+0.06}$.

5 data tables match query

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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CHARGED HADRON PRODUCTION IN THE UPSILON REGION

Avery, P. ; Bebek, C. ; Berkelman, Karl ; et al.

PRINT-83-0867, 1983.

Inspire Record 192220 DOI 10.17182/hepdata.12222

None

2 data tables match query

Table 2

NUMBERS ACTUALLY GIVEN IN GREEN 83 (CORNELL CONF, RED = 1291).

Table 3

NUMBERS ACTUALLY GIVEN IN GREEN 83 (CORNELL CONF, RED = 1291). FOR UPSI(4S) PROTON PRODUCTION SEE ALAM 83, PRL 51/1143/83, RED = 1271.

Cross-sections and leptonic forward-backward asymmetries from the Z0 running of LEP.

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.

Eur.Phys.J.C 16 (2000) 371-405, 2000.

Inspire Record 527605 DOI 10.17182/hepdata.49969

During 1993 and 1995 LEP was run at 3 energies near the Z$^0$peak in order to give improved measurements of the mass and width of the resonance. During 1994, LEP o

14 data tables match query

Table 1

Hadronic cross section measured with the 1993 data. Additional systematic error of 0.10 PCT (efficiencies and backgrounds) and 0.29 PCT (absolute luminosity).

Table 2

Hadronic cross section measured with the 1994 data. Additional systematic error of 0.11 PCT (efficiencies and backgrounds) and 0.11 PCT (absolute luminosity).

Table 3

Hadronic cross section measured with the 1995 data. Additional systematic error of 0.10 PCT (efficiencies and backgrounds) and 0.11 PCT (absolute luminosity).

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Determination of alpha-s from hadronic event shapes measured on the Z0 resonance

The L3 collaboration Adrian, O. ; Aguilar-Benitez, M. ; Ahlen, S. ; et al.

Phys.Lett.B 284 (1992) 471-481, 1992.

Inspire Record 334951 DOI 10.17182/hepdata.29157

We present a study of the global event shape variables thrust and heavy jet mass, of energy-energy correlations and of jet multiplicities based on 250 000 hadronic Z 0 decays. The data are compared to new QCD calculations including resummation of leading and next-to-leading logarithms to all orders. We determine the strong coupling constant α s (91.2 GeV) = 0.125±0.003 (exp) ± 0.008 (theor). The first error is the experimental uncertainty. The second error is due to hadronization uncertainties and approximations in the calculations of the higher order corrections.

3 data tables match query

Table 1

Measured EEC distribution corrected for detector effects and photon radiation. Errors are combined statistical and systematic uncertainties.

Table 2

Measured average jet multiplicities for the K_PT algorithm. All numbers are corrected for detector effects and photon radiation. Errors are combined statistical and systematic uncertainties.

Table 3

Value of strong coupling constant, alpha_s, determined from the data. First error is experimental, the second is theoretical.

Hadronic production by e+ e- collisions at the energy 990 mev with the orsay storage ring

Cosme, G. ; Jean-Marie, B. ; Jullian, S. ; et al.

Phys.Lett.B 40 (1972) 685-688, 1972.

Inspire Record 75666 DOI 10.17182/hepdata.28276

Data were taken at the energy 2 E = 990 MeV to search for multibody events, with the same large solid angle detector which has been used for the measurement of the ϱ , ω and φ production by e + e − annilations. Assuming a π + π − π 0 π 0 production by the quasi two-body process e + e − → ϱ → ωπ 0 we give the correspondi ng cross section σ (e + e − → π + π − π 0 π 0 ) = (1.1 ± 0.5) 10 −32 cm 2 . Since no events with 3 and 4 charged pions have been observed σ (e + e − → π + π − π 0 π − ) ⩽ 1.5 × 10 −33 cm 2 .

1 data table match query

Table 1

RATIO TO MUON PAIR PRODUCTION CALCULATED FROM CROSS SECTION. INCLUDING SYSTEMATIC ERRORS.

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 match query

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.