Burchat, P.R.
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An Improved measurement of alpha-s (M (Z0)) using energy correlations with the OPAL detector at LEP

The OPAL collaboration Acton, P.D. ; Alexander, G. ; Allison, J. ; et al.
Phys.Lett.B 276 (1992) 547-564, 1992.
Inspire Record 321657 DOI 10.17182/hepdata.29245

We report on an improved measurement of the value of the strong coupling constant σ s at the Z 0 peak, using the asymmetry of the energy-energy correlation function. The analysis, based on second-order perturbation theory and a data sample of about 145000 multihadronic Z 0 decays, yields α s ( M z 0 = 0.118±0.001(stat.)±0.003(exp.syst.) −0.004 +0.0009 (theor. syst.), where the theoretical systematic error accounts for uncertainties due to hadronization, the choice of the renormalization scale and unknown higher-order terms. We adjust the parameters of a second-order matrix element Monte Carlo followed by string hadronization to best describe the energy correlation and other hadronic Z 0 decay data. The α s result obtained from this second-order Monte Carlo is found to be unreliable if values of the renormalization scale smaller than about 0.15 E cm are used in the generator.

2 data tables
Table 1

Value of LAMBDA(MSBAR) and ALPHA_S.. The first systematic error is experimental, the second is from theory.

Table 2

The EEC and its asymmetry at the hadron level, unfolded for initial-state radiation and for detector acceptance and resolution. Errors include full statistical and systematic uncertainties.


$\rho^0$ Production in Deep Inelastic $\mu p$ Interactions

The European Muon collaboration Aubert, J.J. ; Bassompierre, G. ; Becks, K.H. ; et al.
Phys.Lett.B 133 (1983) 370-374, 1983.
Inspire Record 192074 DOI 10.17182/hepdata.30613

Inclusive ϱ 0 meson production has been measured in 120 GeV and 280 GeV muon-proton interactions. Distributions of z and p T 2 are presented. Primary ϱ 0 production is found to be equal to that of π 0 production within errors.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


The Ratio of the Nucleon Structure Functions f2 (n) for Iron and Deuterium

The European Muon collaboration Aubert, J.J. ; Bassompierre, G. ; Becks, K.H. ; et al.
Phys.Lett.B 123 (1983) 275-278, 1983.
Inspire Record 188925 DOI 10.17182/hepdata.30745

Using the data on deep inelastic muon scattering on iron and deuterium the ratio of the nucleon structure functions F 2 N ( Fe )/ F 2 N ( D ) is presented. The observed x -dependence of this ratio is in disagreement with existing theoretical predictions.

1 data table
Table 1

RANGE OF Q*2 VARIES WITH X. E.G. AT X=0.05 , 9<Q2<27. AT X=0.65 , 36<Q2<170 GEV**2.


Measurement of Hadronic Azimuthal Distributions in Deep Inelastic Muon Proton Scattering

The European Muon collaboration Aubert, J.J. ; Bassompierre, G. ; Becks, K.H. ; et al.
Phys.Lett.B 130 (1983) 118-122, 1983.
Inspire Record 191233 DOI 10.17182/hepdata.30663

Results on moments of the azimuthal angle ϕ of final state hadrons from 120 GeV and 280 GeV μp scattering are presented. A ϕ asymmetry is observed and its W 2 , Q 2 , z and p T dependences compared with model calculations which include intrinsic transverse momentum and first order QCD corrections. These studies indicate that the observed asymmetry is mainly due to intrinsic transverse momentum k T .

8 data tables
Table 1

No description provided.

Table 2

Typical phi distribution.

Table 3

No description provided.

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MEASUREMENT OF THE DEUTERON STRUCTURE FUNCTION F2 AND A COMPARISON OF PROTON AND NEUTRON STRUCTURE

The European Muon collaboration Aubert, J.J. ; Bassompierre, G. ; Becks, K.H. ; et al.
Phys.Lett.B 123 (1983) 123-126, 1983.
Inspire Record 188737 DOI 10.17182/hepdata.30753

The deuteron structure function F 2 d has been measured in 280 GeV μ + d interactions. Existing measurements of F 2 p , made with the same apparatus, are used to calculate F 2 p − F 2 n and F 2 n F 2 p . The ratio F 2 n F 2 p has a similar x dependence to that of earlier measurements at lower Q 2 .

10 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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HADRON MULTIPLICITY VARIATION WITH Q**2 AND SCALE BREAKING OF THE HADRON DISTRIBUTIONS IN DEEP INELASTIC MUON - PROTON SCATTERING

The European Muon collaboration Arneodo, M. ; Arvidson, A. ; Aubert, J.J. ; et al.
Phys.Lett.B 165 (1985) 222-228, 1985.
Inspire Record 217810 DOI 10.17182/hepdata.30328

Measurements are presented of the variation with Q 2 (scaling violation) of the hadron multiplicity in deep inelastic muon-proton scattering. An increase in the average multiplicity of both the charged hadrons and K 0 mesons is observed with increasing Q 2 or x Bj for fixed centre-of-mass energy W . The study of the shape of the effective fragmentation function D h ( z , W , Q 2 ) shows that the increase of the particle yield with Q 2 takes place for low z particles. The variation of the hadron distributions with Q 2 is also studied in the current fragmentation region where a decrease in multiplicity is observed. Such effects are expected from QCD.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


A MEASUREMENT OF THE DIFFERENCE BETWEEN THE SINGLE NUCLEON CROSS-SECTIONS FOR j / psi MUOPRODUCTION IN IRON AND IN H-2, D-2 TARGETS

The European Muon collaboration Aubert, J.J. ; Bassompierre, G. ; Becks, K.H. ; et al.
Phys.Lett.B 152 (1985) 433-438, 1985.
Inspire Record 207459 DOI 10.17182/hepdata.30432

The cross sections for J ψ production have been measured in interactions of 280 GeV μ + on hydrogen and deuterium (H, D) and also in interactions of 250 GeV μ + on iron. The single-nucleon cross sections in iron are found to be larger than those in H, D. The mean ratio of the iron to H, D photoproduction cross sections in the range 60 < v < 200 GeV is 1.45 ±0.12 (statistical) ±0.22 (systematic error). Within the framework of the photon-gluon fusion model, this indicates that the gluon density per nucleon is ∼45% larger in iron than in H, D in the range 0.026 < x < 0.085, on a mass scale Q 2 eff ∼M 2 J ψ .

3 data tables
Table 1

First table is from combined H and DEUT data at 280 Gev. Second table is from FE data at 250 Gev.

Table 2

First table is from combined H and DEUT data at 280 Gev. Second table is from FE data at 250 Gev.

Table 3

THIS TABLE IS THE RATIO OF THE EFFECTIVE GLUON DISTRIBUTIONS IN IRON AND HYDROGEN(DEUTERIUM) ASSUMING THAT PHOTON-GLUON FUSION IS THE RELEVANT MECHANISM FOR J/PSI PRODUCTION.


Production of $\pi^0$ mesons in muon - hydrogen interactions at 200-GeV

The European Muon collaboration Aubert, J.J. ; Bassompierre, G. ; Becks, K.H. ; et al.
Z.Phys.C 18 (1983) 189, 1983.
Inspire Record 189283 DOI 10.17182/hepdata.16369

Thez andpT2 distributions of π0 mesons produced by the interaction of 200 GeV muons on hydrogen are presented. Comparisons are made with other π0 and charged hadron data and with the predictions of perturbative QCD. The data show a rise of 〈pT2〉 withW2 which is consistent with QCD, and withz2 which requires a contribution from a primordialkT. The fraction of total energy which appears as π0 mesons is 0.27±0.05.

1 data table
Table 1

No description provided.


A Precise measurement of the average b hadron lifetime

The ALEPH collaboration Buskulic, D. ; Casper, D. ; De Bonis, I. ; et al.
Phys.Lett.B 369 (1996) 151-162, 1996.
Inspire Record 401554 DOI 10.17182/hepdata.52363

An improved measurement of the average b hadron lifetime is performed using a sample of 1.5 million hadronic Z decays, collected during the 1991–1993 runs of ALEPH, with the silicon vertex detector fully operational. This uses the three-dimensional impact parameter distribution of lepton tracks coming from semileptonic b decays and yields an average b hadron lifetime of 1.533 ± 0.013 ± 0.022 ps.

1 data table
Table 1

No description provided.