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Inclusive single-particle production in two-photon collisions at LEP II with the DELPHI detector

The DELPHI collaboration Abdallah, J. ; Abreu, P. ; Adam, W. ; et al.
Phys.Lett.B 678 (2009) 444-449, 2009.
Inspire Record 824322 DOI 10.17182/hepdata.52859

A study of the inclusive charged hadron production in two-photon collisions is described. The data were collected with the DELPHI detector at LEP II. Results on the inclusive single-particle p_T distribution and the differential charged hadrons dsigma/dp_T cross-section are presented and compared to the predictions of perturbative NLO QCD calculations and to published results.

1 data table

Differential inclusive DSIG/DPT distribution of charged particles produced in GAMMA* GAMMA* interaction with two pseudorapidity cut offs.


Measurement and interpretation of fermion-pair production at LEP energies above the Z resonance.

The DELPHI collaboration Abdallah, J. ; Abreu, P. ; Adam, W. ; et al.
Eur.Phys.J.C 45 (2006) 589-632, 2006.
Inspire Record 699726 DOI 10.17182/hepdata.48590

This paper presents DELPHI measurements and interpretations of cross-sections, forward-backward asymmetries, and angular distributions, for the e+e- -> ffbar process for centre-of-mass energies above the Z resonance, from sqrt(s) ~ 130 - 207 GeV at the LEP collider. The measurements are consistent with the predictions of the Standard Model and are used to study a variety of models including the S-Matrix ansatz for e+e- -> ffbar scattering and several models which include physics beyond the Standard Model: the exchange of Z' bosons, contact interactions between fermions, the exchange of gravitons in large extra dimensions and the exchange of sneutrino in R-parity violating supersymmetry.

29 data tables

Measured cross sections and forward-backward asymmetries for non-radiative E+ E- --> E+ E- events.

Differential cross sections for non-radiative E+ E- --> E+ E- events at centre of mass energy 189 GeV.

Differential cross sections for non-radiative E+ E- --> E+ E- events at centre of mass energy 192 GeV.

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Measurement of the W pair production cross-section and W branching ratios in e+ e- collisions at s**(1/2) = 161-GeV to 209-GeV.

The DELPHI collaboration Abdallah, J. ; Abreu, P. ; Adam, W. ; et al.
Eur.Phys.J.C 34 (2004) 127-144, 2004.
Inspire Record 635851 DOI 10.17182/hepdata.48832

These final results on e+e- -> W+W- production cross-section measurements at LEP2 use data collected by the DELPHI detector at centre-of-mass energies up to 209 GeV. Measurements of total cross-sections, W angular differential distributions and decay branching fractions, and the value of the CKM element |V_{cs}| are compared to the expectations of the Standard Model. These results supersede all values previously published by DELPHI.

5 data tables

W pair production cross section for the fully hadronic channel.

W pair production cross section for the semi-leptonic decay channel.

W pair production cross section for the fully leptonic decay channel.

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Study of tau-pair production in photon photon collisions at LEP and limits on the anomalous electromagnetic moments of the tau lepton.

The DELPHI collaboration Abdallah, J. ; Abreu, P. ; Adam, W. ; et al.
Eur.Phys.J.C 35 (2004) 159-170, 2004.
Inspire Record 638199 DOI 10.17182/hepdata.48843

Tau-pair production in the process e+e- -> e+e-tau+tau- was studied using data collected by the DELPHI experiment at LEP2 during the years 1997 - 2000. The corresponding integrated luminosity is 650 pb^{-1}. The values of the cross-section obtained are found to be in agreement with QED predictions. Limits on the anomalous magnetic and electric dipole moments of the tau lepton are deduced.

1 data table

The measured cross sections for the individual samples divided into years and the overall average value.


A study of the energy evolution of event shape distributions and their means with the DELPHI detector at LEP.

The DELPHI collaboration Abdallah, J. ; Abreu, P. ; Adam, W. ; et al.
Eur.Phys.J.C 29 (2003) 285-312, 2003.
Inspire Record 620250 DOI 10.17182/hepdata.13029

Infrared and collinear safe event shape distributions and their mean values are determined in e+e- collisions at centre-of-mass energies between 45 and 202 GeV. A phenomenological analysis based on power correction models including hadron mass effects for both differential distributions and mean values is presented. Using power corrections, alpha_s is extracted from the mean values and shapes. In an alternative approach, renormalisation group invariance (RGI) is used as an explicit constraint, leading to a consistent description of mean values without the need for sizeable power corrections. The QCD beta-function is precisely measured using this approach. From the DELPHI data on Thrust, including data from low energy experiments, one finds beta_0 = 7.86 +/- 0.32 for the one loop coefficient of the beta-function or, assuming QCD, n_f = 4.75 +/- 0.44 for the number of active flavours. These values agree well with the QCD expectation of beta_0=7.67 and n_f=5. A direct measurement of the full logarithmic energy slope excludes light gluinos with a mass below 5 GeV.

71 data tables

1-THRUST distribution.

THRUST-MAJOR distribution.

THRUST-MINOR distribution.

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Single intermediate vector boson production in e+ e- collisions at s**(1/2) = 183-GeV and 189-GeV.

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Phys.Lett.B 515 (2001) 238-254, 2001.
Inspire Record 560550 DOI 10.17182/hepdata.49830

The cross-sections for the production of single charged and neutral intermediate vector bosons were measured using integrated luminosities of 52 pb^{-1} and 154 pb^{-1} collected by the DELPHI experiment at centre-of-mass energies of 182.6 GeV and 188.6 GeV, respectively. The cross-sections for the reactions were determined in limited kinematic regions. The results found are in agreement with the Standard Model predictions for these channels.

4 data tables

Cross sections for single-W production in the (E- NUEBAR Q QBAR + CC) and (E- NUEBAR LEPTON LEPTONBAR) + CC) channels.

Cross sections for the E NU E NU channel, which includes contributions from both single-W and from single-Z0 with a large interference bewteen the two processes.

Cross sections for single-Z0 production in the hadronic channel.

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Measurement of the Z Z cross-section in e+ e- interactions at 183-GeV - 189-GeV.

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Phys.Lett.B 497 (2001) 199-213, 2001.
Inspire Record 539640 DOI 10.17182/hepdata.49912

Measurements of on-shell ZZ production are described, using data collected by DELPHI in 1997 and 1998, at centre-of-mass energies sqrt(s) = 182.6 GeV and 188.6 GeV respectively. Results obtained in each of the final states q qbar q qbar, mu+mu- q qbar, e+e- q qbar, nu nubar q qbar, l+l-l+l-, and nu nubar l+l- are presented. The measured cross-sections for on-shell ZZ production via the tree-level doubly-resonant graphs (NC02) are: sigma_{NC02}(182.6 GeV) = 0.38 +- 0.18 (stat) +- 0.04 (syst) pb, sigma_{NC02}(188.6 GeV) = 0.60 +- 0.13 (stat) +- 0.07 (syst) pb. They are consistent with the Standard Model expectations of 0.25 pb and 0.65 pb at each energy.

1 data table

No description provided.


Charged and Identified Particles in the Hadronic Decay of W Bosons and in e+e- -> q qbar from 130 to 200 GeV

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Eur.Phys.J.C 18 (2000) 203-228, 2000.
Inspire Record 526164 DOI 10.17182/hepdata.43294

Inclusive distributions of charged particles in hadronic W decays are experimentally investigated using the statistics collected by the DELPHI experiment at LEP during 1997, 1998 and 1999, at centre-of-mass energies from 183 to around 200 GeV. The possible effects of interconnection between the hadronic decays of two Ws are not observed. Measurements of the average multiplicity for charged and identified particles in q qbar and WW events at centre-of-mass energies from 130 to 200 GeV and in W decays are presented. The results on the average multiplicity of identified particles and on the position xi^* of the maximum of the xi_p = -log(2p/sqrt(s)) distribution are compared with predictions of JETSET and MLLA calculations.

16 data tables

Corrected multiplicites and dispersions of charged particles produced in hadronic decays from QQBAR events. The 200 GeV results are a weighted average fromthe 192, 196 and 200 GeV data.

Average multiplicities of identified hadrons produced in hadronic decays from QQBAR events.

Corrected multiplicites and dispersions of charged particles produced in fully hadronic W decays from two W 4Q and 2Q events.

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Measurement and Interpretation of Fermion-Pair Production at LEP Energies of 183 and 189 GeV

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Phys.Lett.B 485 (2000) 45-61, 2000.
Inspire Record 529847 DOI 10.17182/hepdata.49937

An analysis of the data collected in 1997 and 1998 with the DELPHI detector at e+e- collision energies close to 183 and 189 GeV was performed in order to extract the hadronic and leptonic fermion-pair cross-sections, as well as the leptonic forward-backward asymmetries and angular distributions. The data are used to put limit on contact interactions between fermions, the exchange of R-parity violating SUSY sneutrinos, Z' bosons and the existence of gravity in extra dimensions.

7 data tables

No description provided.

No description provided.

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Photon Events with Missing Energy at sqrt(s) = 183 to 189 GeV

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Eur.Phys.J.C 17 (2000) 53-65, 2000.
Inspire Record 537913 DOI 10.17182/hepdata.32093

The production of single photons has been studied in the reaction e+e- -> gamma + invisible particles at centre-of-mass energies of 183 GeV and 189 GeV. A previously published analysis of events with multi-photon final states accompanied by missing energy has been updated with 189 GeV data. The data were collected with the DELPHI detector and correspond to integrated luminosities of about 51 pb^{-1} and 158 pb^{-1} at the two energies. The number of light neutrino families is measured to be 2.84 +/- 0.15(stat) +/- 0.14(syst). The absence of an excess of events beyond that expected from Standard Model processes is used to set limits on new physics as described by supersymmetric and composite models. A limit on the gravitational scale is also determined.

2 data tables

No description provided.

Combined result.