Abrahantes Quintana, A.
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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.


A Measurement of the b anti-b forward backward asymmetry using the semileptonic decay into muons

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.
Phys.Lett.B 276 (1992) 536-546, 1992.
Inspire Record 322498 DOI 10.17182/hepdata.29264

The forward-backward asymmetry of bottom quarks is measured with statistics of approximately 80 000 hadronic Z 0 decays produced in e + e − collisions at a centre of mass energy of √ s ≈ M z . The tagging of b quark events has been performed using the semileptonic decay channel b→X+ μ . Because the asymmetry depends on the weak coupling, this leads to a precise measurement of the electroweak mixing angle sin 2 θ w . The experimental result is A FB b = 0.115±0.043(stat.)±0.013(syst.). After correcting the value for the B 0 B 0 mixing this becomes A FB b =0.161±0.060(stat.)±0.021(syst.) corresponding to sin 2 θ W MS =0.221±0.011( stat. )±0.004( syst. ) .

3 data tables
Table 1

Experimentally measured asymmetry.

Table 2

Asymmetry corrected for mixing using mixing parameter 0.143 +- 0.023.

Table 3

SIN2TW measured in MSBAR scheme.


Measurement of the ratio sigma B (W ---> tau-neutrino) / sigma B (W ---> e neutrino), in p anti-p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Amidei, Dante E. ; Apollinari, G. ; et al.
Phys.Rev.Lett. 68 (1992) 3398-3402, 1992.
Inspire Record 324086 DOI 10.17182/hepdata.19851

We have observed over 102 events of the type W→τν followed by τ→ hadrons, where the taus are identified by their decay into one or three charged particles. We measure the cross section times branching ratio for pp¯→W→τν and compare it to the value for W→eν to directly measure the ratio of weak coupling constants gτ/ge. We find gτ/ge=0.97±0.07, consistent with lepton universality.

3 data tables
Table 1

Results from the missing ET trigger.

Table 2

Results from the tau trigger.

Table 3

Results from the combined ET trigger.


Backward emitted protons in interactions of neutrinos with nuclei in photoemulsion. FNAL-564 experiment

Dayon, M. ; Rappoport, V. ; Smirnitsky, V. ; et al.
Z.Phys.C 56 (1992) 391-393, 1992.
Inspire Record 345621 DOI 10.17182/hepdata.14532

Backward emitted protons with momentump>0.3 GeV/c in interactions of neutrino in the energy range 10–200 GeV with photoemulsion nuclei were investigated. Energy spectrum slope parameter of backward protons was measured to beT0=48.9±7.9 MeV. TheA-dependence power index of relative mean yield of backward protons was found to bea=0.68±0.12. A drop in the mean yield of backward protons at the four momentum squared over ∼15 (GeV/c)2 (the neutrino energy over ∼50 GeV) was observed.

3 data tables
Table 1

NUCLEUS IS AVERAGE NUCLEI OF NUCLEAR EMULSION, <A> ABOUT 80.

Table 2

NUCLEUS IS AVERAGE NUCLEI OF NUCLEAR EMULSION, <A> ABOUT 80.

Table 3

NUCLEUS IS AVERAGE NUCLEI OF NUCLEAR EMULSION, <A> ABOUT 80.


rivet Analysis
An Experimental study of the process gamma gamma ---> pi+ pi-

The CELLO collaboration Behrend, H.J. ; Criegee, L. ; Field, J.H. ; et al.
Z.Phys.C 56 (1992) 381-390, 1992.
Inspire Record 345437 DOI 10.17182/hepdata.14534

Using the CELLO detector, we have measured cross sections for the processγγ→π+π− in the mass range 0.75–1.9 GeV/c2. A partial wave fit to the data indicates the presence of a sizeableS-wave amplitude with signs of resonant behaviour. Values for the γγ width of thef2(1270) are given, showing the model-dependence of this quantity. At higher dipion masses, the model of Brodsky and Lepage is found to give an order of magnitude description of the data.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Differential cross-sections and analyzing powers for anti-p p ---> pi- pi+ and K- K+ from 360-MeV/c to 1550-MeV/c

Hasan, A. ; Bugg, D.V. ; Hall, J.R. ; et al.
Nucl.Phys.B 378 (1992) 3-51, 1992.
Inspire Record 339576 DOI 10.17182/hepdata.6880

Analysing powers and differential cross sections for p p → π − π + and p p → K − K + have been measured over the full angular range using a polarised target at LEAR at 20 beam momenta from 360 to 1550 MeV/ c . Discrepancies in the normalisation of earlier d σ/ d Ω data at low momenta are clarified. Above 1000 MeV/ c , A 0N results confirm values close to +1 over most of the angular range for both reactions, in excellent agreement with earlier data of lower statistics. Below 1000 MeV/ c , where the analysing power is measured for the first time, large variations of A 0N with energy and angle are present.

84 data tables
Table 1

No description provided.

Table 2

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Table 3

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Determination of $alpha_{s}$ in second order {QCD} from hadronic $Z$ decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.
Z.Phys.C 54 (1992) 55-74, 1992.
Inspire Record 333272 DOI 10.17182/hepdata.14603

Distributions of event shape variables obtained from 120600 hadronicZ decays measured with the DELPHI detector are compared to the predictions of QCD based event generators. Values of the strong coupling constant αs are derived as a function of the renormalization scale from a quantitative analysis of eight hadronic distributions. The final result, αs(MZ), is based on second order perturbation theory and uses two hadronization corrections, one computed with a parton shower model and the other with a QCD matrix element model.

9 data tables
Table 1

Experimental differential Thrust distributions.

Table 2

Experimental differential Oblateness distributions.

Table 3

Experimental differential C-parameter distributions.

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Meson production in p + U, O + U and S + U interactions at 200-GeV/nucleon.

The NA38 collaboration Abreu, M.C. ; Baglin, C. ; Baldisseri, A. ; et al.
Z.Phys.C 55 (1992) 365-371, 1992.
Inspire Record 344266 DOI 10.17182/hepdata.14583

Meson production in proton, oxygen and sulphur interactions with uranium targets at 200 GeV/nucleon is studied. We measure the inclusive meson cross-section d σ/dPT2 and its evolution fromp+U to S+U. The cross-section fitted with an exponential gives an inverse slopePT0 of the order of 210 MeV/c. As a function of the neutral transverse energy,PT0 values show a slight rise followed by a plateau. The normalized difference (σ+−σ−)/σ− between positive and negative meson cross-sections is found to increase withET.

6 data tables
Table 1

No description provided.

Table 2

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Table 3

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Inclusive production of eta mesons in pi p, K p and gamma p collisions at energies around 100-GeV.

The Omega Photon collaboration Apsimon, R.J. ; Atkinson, M. ; Baake, M. ; et al.
Z.Phys.C 54 (1992) 185-191, 1992.
Inspire Record 339919 DOI 10.17182/hepdata.14710

Measurements are reported of inclusive production of η-mesons in the beam fragmentation region in γp, πp andKp collisions. Results include a small but significant departure from VMD, and a pronounced rise in theη/π0 ratio with increasingpT.

21 data tables
Table 1

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Table 3

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Neutral strange particle production in K+ and pi+ collisions with Al and Au nuclei at 250-GeV/c

The NA22 collaboration Botterweck, F. ; Charlet, M. ; Chliapnikov, P.V. ; et al.
Z.Phys.C 55 (1992) 373-382, 1992.
Inspire Record 333307 DOI 10.17182/hepdata.14584

Data are presented on inclusiveKs0 and Λ production inK+ and π+ collisions with Al and Au nuclei at 250 GeV/c. Results are given on total inclusive cross sections and theA dependence, as well as on distributions in Feynman-xF, rapidityy and transverse momentum. Ratios ofKS0 and of Λ to π+ production are presented. The data are compared with predictions of the quark-parton model FRITIOF.

50 data tables
Table 1

No description provided.

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