Nuclear structure function in carbon near x = 1

The BCDMS collaboration Benvenuti, A.C. ; Bollini, D. ; Camporesi, T. ; et al.
Z.Phys.C 63 (1994) 29-36, 1994.
Inspire Record 374300 DOI 10.17182/hepdata.48235

Data from deep inelastic scattering of 200 GeV muons on a carbon target with squared four-momentum transfer 52 GeV2≤Q2≤200 GeV2 were analysed in the region of the Bjorken variable close tox=1, which is the kinematic limit for scattering on a free nucleon. At this value ofx, the carbon structure function is found to beF2C≈1.2·10−4. Thex dependence of the structure function forx>0.8 is well described by an exponentialF2C∞exp(−sx) withs=16.5±0.6.

5 data tables

No description provided.

Multiplicative factors by which F2 has to be multiplied or divided to allow for a systematic uncertainty in detector resolution.

Multiplicative factors by which F2 has to be multiplied or divided to allow for a systematic uncertainty in the beam energy.

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Charged particle multiplicity distributions in Z0 hadronic decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.
Z.Phys.C 50 (1991) 185-194, 1991.
Inspire Record 301657 DOI 10.17182/hepdata.15028

This paper presents an analysis of the multiplicity distributions of charged particles produced inZ0 hadronic decays in the DELPHI detector. It is based on a sample of 25364 events. The average multiplicity is <nch>=20.71±0.04(stat)±0.77(syst) and the dispersionD=6.28±0.03(stat)±0.43(syst). The data are compared with the results at lower energies and with the predictions of phenomenological models. The Lund parton shower model describes the data reasonably well. The multiplicity distributions show approximate KNO-scaling. They also show positive forward-backward correlations that are strongest in the central region of rapidity and for particles of opposite charge.

5 data tables

Charged particle multiplicity distribution for the raw data in full phase space.

Charged particle multiplicity distribution for full phase space. Errors include systematics. A 2 pct correction for excess electrons from photon conversions is not included. The first two points, at N=2 and 4, were not measured but taken from the Lund PS model.

Charged particle multiplicity distribution for single hemisphere. Errors include systematics. A 2 pct correction for excess electrons from photon conversions is not included.

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Experimental study of the triple gluon vertex

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.
Phys.Lett.B 255 (1991) 466-476, 1991.
Inspire Record 301659 DOI 10.17182/hepdata.48514

In four-jet events from e + e − →Z 0 →multihadrons one can separate the three principal contributions from the triple-gluon vertex, double gluon-bremsstrahlung and the secondary quark-antiquark production, using the shape of the two-dimensional angular distributions in the generalized Nachtmann-Reiter angle θ NR ∗ and the opening angle of the secondary jets. Thus one can identify directly the contribution from the triple-gluon vertex without comparison with a specific non-QCD model. Applying this new method to events taken with the DELPHI-detector we get for the ratio of the colour factor N c to the fermionic Casimir operator C F : N c C F = 2.55 ± 0.55 ( stat. ) ± 0.4 ( fragm. + models ) ± 0.2 ( error in bias ) in agreement with the value 2.25 expected in QCD from N c =3 and C F = 4 3 .

1 data table

NC, CF, and TR are the color factors for SU(3) group.


Energy-energy correlations in hadronic final states from Z0 decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.
Phys.Lett.B 252 (1990) 149-158, 1990.
Inspire Record 300161 DOI 10.17182/hepdata.29534

We have studied the energy-energy angular correlations in hadronic final states from Z 0 decay using the DELPHI detector at LEP. From a comparison with Monte Carlo calculations based on the exact second order QCD matrix element and string fragmentation we find that Λ (5) MS =104 +25 -20 ( stat. ) +25 -20( syst. ) +30 00 ) theor. ) . MeV, which corresponds to α s (91 GeV)=0.106±0.003(stat.)±0.003(syst.) +0.003 -0.000 (theor). The theoretical error stems from different choices for the renormalization scale of α s . In the Monte Carlo simulation the scale of α s as well as the fragmentation parameters have been optimized to described reasonably well all aspects of multihadron production.

2 data tables

Data requested from the authors.

Values of LAMBDA-MSBAR(5) and ALPHA-S(91 GeV) deduced from the EEC measurements. The second systematic error is from the theory.


Measurement of the partial width of the decay of the Z0 into charm quark pairs

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.
Phys.Lett.B 252 (1990) 140-148, 1990.
Inspire Record 300162 DOI 10.17182/hepdata.48518

A determination of the partial width Γ c c ̄ of the Z 0 boson into charm quark pairs is presented, based on a total sample of 36 900 Z 0 hadronic decays measured with the DELPHI detector at the LEP collider. The production rate of cc̄ events is derived from the inclusive analysis of charged pions coming from the decay of charmed meson D ∗+ → D 0 π + and D ∗− → D ̄ 0 π − where the π ± is constrained by kinematics to have a low p T with respect to the axis. The probability to produce these π ± from D ∗± decay in cc̄ events is taken to be 0.31 ±_0.05 as measured at √ s =10.55 GeV. The measured relative partial width Γ c c ̄ Γ h = 0.162± 0.030 ( stat. ) ±0.050 ( syst. ) is in good agreement with the standard moel value of 0.171. Together with our previous measurement of the total hadronic width Γ h this implies Γ c c ̄ = 282±53 ( stat. )±88( syst. ) MeV .

1 data table

No description provided.


Charged multiplicity and rapidity distributions in Z0 hadronic decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.
CERN-PPE-90-117, 1990.
Inspire Record 299521 DOI 10.17182/hepdata.48523

None

1 data table

No description provided.


DELPHI results on the Z0 resonance parameters through its hadronic and leptonic decay modes

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.
CERN-PPE-90-119, 1990.
Inspire Record 298840 DOI 10.17182/hepdata.47313

None

7 data tables

Overall systematic error is 2.3 pct.

Overall systematic error is 2.6 pct.

Overall systematic error is 2.8 pct.

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A Comparison of jet production rates on the Z0 resonance to perturbative QCD

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.
Phys.Lett.B 247 (1990) 167-176, 1990.
Inspire Record 297698 DOI 10.17182/hepdata.29653

The production rates for 2-, 3-, 4- and 5-jet hadronic final states have been measured with the DELPHI detector at the e + e − storage ring LEP at centre of mass energies around 91.5 GeV. Fully corrected data are compared to O(α 2 s ) QCD matrix element calculations and the QCD scale parameter Λ MS is determined for different parametrizations of the renormalization scale ω 2 . Including all uncertainties our result is α s ( M 2 Z )=0.114±0.003[stat.]±0.004[syst.]±0.012[theor.].

2 data tables

Corrected jet rates.

Second systematic error is theoretical.


A Precise Measurement of the $Z$ Resonance Parameters Through Its Hadronic Decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.
Phys.Lett.B 241 (1990) 435-448, 1990.
Inspire Record 295501 DOI 10.17182/hepdata.29722

A measurement of the cross section for e + e - → hadrons using 11 000 hadronic decays of the Z boson at ten different center-of-mass energies is presented. A three-parameter fit gives the following values for the Z mass M z , the total width Γ z , the product of the electronic and hadronic partial widths Γ e Γ h , and the unfolded pole cross section σ 0 : M Z =91.171±0.030(stat)±0.030 (beam) GeV, Γ Z =2.511±0.065 GeV, Γ e Γ h =0.148±0.006 (stat.)±0.004 (syst.) GeV 2 , σ 0 =41.6±0.7(stat.)±1.1 (syst.) nb,

1 data table

No description provided.


Study of the Leptonic Decays of the $Z^0$ Boson

The DELPHI collaboration Aarnio, P. ; Abreu, P. ; Adam, W. ; et al.
Phys.Lett.B 241 (1990) 425-434, 1990.
Inspire Record 295500 DOI 10.17182/hepdata.15431

Measurements are presented of the cross section ratios R ℓ = σ ℓ ( e + e − →ℓ + ℓ − ) σ h ( e + e − →hadrons) for ℓ=e, μ and τ using data taken from a scan around the Z 0 . The results are R e =(5.09± o .32±0.18)%, R μ =(0.46±0.35±0.17)% and R τ =(4.72±0.38±0.29)% where, for the ratio R e , the t -channel contribution has been subtracted. These results are consistent with the hypothesis of lepton universality and test this hypothesis at the energy scale s ∼8300 GeV 2 . The absolute cross sections σ ℓ (e + e − →ℓ + ℓ − ) have also been measured. From the cross sections the leptonic partial widths Γ e =(83.2±3.0±2.4) MeV, (Γ e Γ μ ) 1 2 =(84.6±3.0±2.4) MeV and (Γ e Γ τ ) 1 2 =(82.6±3.3±3.2) MeV have been extracted. Assuming lepton universality the ratio Γ ℓ Γ h =(4.89±0.20±0.12) × 10 −2 w was obtained, together with Γ ℓ =(83.6±1.8±2.2) MeV. The number of light neutrino species is determined to be N v =3.12±0.24±0.25. Al the data are consistent with the predictions of the standard model.

4 data tables

E+ E- final state is t-channel subtracted.

No t-channel subtraction. Statistical errors only.

Statistical errors only.

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