Date

Forward produced hadrons in mu p and mu d scattering and investigation of the charge structure of the nucleon

The European Muon collaboration Ashman, J. ; Badelek, B. ; Baum, G. ; et al.
Z.Phys.C 52 (1991) 361-388, 1991.
Inspire Record 314883 DOI 10.17182/hepdata.1432

Final data measured with the EMC forward spectrometer are presented on the production of forward charged hadrons in μp and μd scattering at incident beam energies between 100 and 280 GeV. The large statistic of 373 000 events allows a study of the semi-inclusive hadron production as a function ofz,pT2 and 〈pT2〉 in smallQ2,xBj andW bins. Charge multiplicity ratios and differences as a function ofz andxBj are given forp, d andn-targets. From the differences of charge multiplicities the ratio of the valence quark distributions of the protondv(x)/uv(x) is determined for the first time in charged lepton scattering. The Gronau et al. sum rule is tested, the measured sum being 0.31±0.06 stat. ±0.05 syst., compared with the theoretical expectation of 2/7≈0.286. The measured sum corresponds to an absolute value of the ratio of thed andu quark charge of 0.44±0.10 stat.±0.08 syst.

129 data tables

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A Measurement of Global Event Shape Distributions in the Hadronic Decays of the $\Z^0$

The OPAL collaboration Akrawy, M.Z. ; Alexander, G. ; Allison, John ; et al.
Z.Phys.C 47 (1990) 505-522, 1990.
Inspire Record 295613 DOI 10.17182/hepdata.15152

We present measurements of global event shape distributions in the hadronic decays of theZ0. The data sample, corresponding to an integrated luminosity of about 1.3 pb−1, was collected with the OPAL detector at LEP. Most of the experimental distributions we present are unfolded for the finite acceptance and resolution of the OPAL detector. Through comparison with our unfolded data, we tune the parameter values of several Monte Carlo computer programs which simulate perturbative QCD and the hadronization of partons. Jetset version 7.2, Herwig version 3.4 and Ariadne version 3.1 all provide good descriptions of the experimental distributions. They in addition describe lower energy data with the parameter values adjusted at theZ0 energy. A complete second order matrix element Monte Carlo program with a modified perturbation scale is also compared to our 91 GeV data and its parameter values are adjusted. We obtained an unfolded value for the mean charged multiplicity of 21.28±0.04±0.84, where the first error is statistical and the second is systematic.

9 data tables

Corrected Thrust distribution.

Corrected Major distribution.

Corrected Minor distribution.

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Measurements of the $u$ Valence Quark Distribution Function in the Proton and $u$ Quark Fragmentation Functions

The European Muon collaboration Arneodo, M. ; Arvidson, A. ; Aubert, J.J. ; et al.
Nucl.Phys.B 321 (1989) 541-560, 1989.
Inspire Record 276746 DOI 10.17182/hepdata.33218

A new determination of the u valence quark distribution function in the proton is obtained from the analysis of identified charged pions, kaons, protons and antiprotons produced in muon-proton and muon-deuteron scattering. The comparison with results obtained in inclusive deep inelastic lepton-nucleon scattering provides a further test of the quark-parton model. The u quark fragmentation functions into positive and negative pions, kaons, protons and antiprotons are also measured.

6 data tables

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Evidence for Anomalous Prompt Photons in Deep Inelastic Muon Scattering at 200-{GeV}

The European Muon collaboration Aubert, J.J. ; Bassompierre, G. ; Becks, K.H. ; et al.
Phys.Lett.B 218 (1989) 248-256, 1989.
Inspire Record 261250 DOI 10.17182/hepdata.29855

The inclusive yield of photons has been measured from deep inelastic interactions of 200 GeV muons on hydrogen. After subtracting the contributions from hadron electromagnetic decays and Bethe-Heitler muon bremsstrahlung, residual photons are observed at low p T and low z at a mean level of 0.15±0.06 per interaction. The quark Compton scattering process is unable to explain the data, thus indicating an anomalous photon production.

2 data tables

Z distribution of anomalous direct photons.

PT distribution of anomalous direct photons.


Exclusive $\rho^0$ and $\phi$ Production in Deep Inelastic Muon Scattering

The European Muon collaboration Ashman, J. ; Badelek, B. ; Baum, G. ; et al.
Z.Phys.C 39 (1988) 169, 1988.
Inspire Record 252743 DOI 10.17182/hepdata.15619

Data are presented on exclusive ρ0 and ϕ production in deep inelastic muon scattering from a target consisting mainly of nitrogen. The ratio of the total cross sections for ρ0 and ϕ production is found to be 9∶(1.6±0.4) at 〈Q2〉=7.5 GeV2, consistent with theSU(3) prediction of 9∶2. Thet dependence for exclusive ρ0 production is found to become shallover asQ2 increases and, for largeQ2, thet dependence is typical of that for a hard scattering process. Furthermore, the ratio of the cross sections for coherent: incoherent production from nitrogen is found to decrease rapidly withQ2. Such behaviour indicates that even for exclusive vector meson production the virtual photon behaves predominantly as an electromagnetic probe.

6 data tables

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COMPARISON BETWEEN HADRONIC FINAL STATES PRODUCED IN mu p AND e+ e- INTERACTIONS

The European Muon collaboration Arneodo, M. ; Arvidson, A. ; Aubert, J.J. ; et al.
Z.Phys.C 35 (1987) 417, 1987.
Inspire Record 233424 DOI 10.17182/hepdata.16655

A comparison is made between the properties of the final state hadrons produced in 280 GeV μp interactions and ine+e− annihilation. The Lund model of hadroproduction is used as an aid in understanding the differences observed. The hadron distributions from μp ande+e− interactions are consistent with the quark parton model assumption of environmental independence, provided that the differences in heavy quark production and hard QCD effects in the two processes are taken into account. A comparison with aK+p experiment is also made. Values are also determined for the Lund model parameters σq = 0.410 ± 0.002 ± 0.020 GeV and σ′ = 0.29−0.15 −0.13+0.09+0.10 GeV, controlling the transverse momenta in fragmentation and intrinsic transverse momenta of the struck quark respectively.

23 data tables

With respect to the virtual photon axis.

With respect to the sphericity axis.

With respect to the thrust axis.

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CHARGED D* MESON PRODUCTION IN e+ e- ANNIHILATION AT S**(1/2) = 29-GeV

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Armitage, J.C. ; et al.
Phys.Rev.D 34 (1986) 1945, 1986.
Inspire Record 217416 DOI 10.17182/hepdata.23509

The production of charmed D* mesons in e+e− annihilations at a center-of-mass energy of 29 GeV has been studied using the time-projection-chamber (TPC) detector at the SLAC storage ring PEP. The production cross section, fragmentation function, and forward-backward asymmetry due to electroweak effects are measured, and a limit on D0-D¯0 mixing is determined.

2 data tables

No description provided.

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A DETERMINATION OF THE FRAGMENTATION FUNCTIONS OF u QUARKS INTO CHARGED PIONS

The European Muon collaboration Aubert, J.J. ; Bassompierre, G. ; Becks, K.H. ; et al.
Phys.Lett.B 160 (1985) 417-420, 1985.
Inspire Record 213987 DOI 10.17182/hepdata.49627

The fragmentation functions of u-quarks into positive and negative pions are determined from an analysis of identified pions produced in deep inelastic muon-deuterium scattering. The method adopted is not sensitive to the knowledge of the primary quark distribution functions. The fragmentation of u quarks to positive pions is found to fall less steeply in z than that to negative pions as expected in the quark parton model.

1 data table

Here Z=P(P=3)/E(P=3).


TESTS OF MODELS FOR PARTON FRAGMENTATION USING THREE JET EVENTS IN e+ e- ANNIHILATION the s**(1/2) = 29-GeV

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Bakken, J.A. ; et al.
Phys.Rev.Lett. 54 (1985) 270, 1985.
Inspire Record 205871 DOI 10.17182/hepdata.20358

The distribution of particles in three-jet events is compared with the predictions of three fragmentation models currently in use: the Lund string model, the Webber cluster model, and an independent fragmentation model. The Lund model and, to a certain extent, the Webber model provide reasonable descriptions of the data. The independent fragmentation model does not describe the distribution of particles at large angles with respect to the jet axes. The results provide evidence that the sources of hadrons are Lorentz boosted with respect to the overall c.m.

1 data table

No description provided.


Transverse Momentum and Its Compensation in Current and Target Jets in Deep Inelastic Muon - Proton Scattering

The European Muon collaboration Arneodo, M. ; Arvidson, A. ; Aubert, J.J. ; et al.
Phys.Lett.B 149 (1984) 415-420, 1984.
Inspire Record 203149 DOI 10.17182/hepdata.30476

Results are presented on the transverse momentum distributions of charged hadrons in 280 GeV muon-proton deep inelastic interactions. The transverse momenta are defined relative to the accurately measured virtual photon direction and the experiment has almost complete angular acceptance for the final state hadrons. Significantly larger values of the average transverse momentum squared are found for the forward going hadrons than for the target remnants. This result, combined with a study of the rapidity region over which the transverse momentum is compensated, can be explained by a significant contribution from soft gluon radiation, but not by a large value of the primordial transverse momentum of the struck quark.

5 data tables

Errors given are statistical only.

Errors are statistical only.

Errors are statistical only.

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