HEPData Search

Showing 9 of 49 results

rivet Analysis
Studies of quantum chromodynamics with the ALEPH detector

The ALEPH collaboration Barate, R. ; Buskulic, D. ; Decamp, D. ; et al.

Phys.Rept. 294 (1998) 1-165, 1998.

Inspire Record 428072 DOI 10.17182/hepdata.47582

Previously published and as yet unpublished QCD results obtained with the ALEPH detector at LEP1 are presented. The unprecedented statistics allows detailed studies of both perturbative and non-perturbative aspects of strong interactions to be carried out using hadronic Z and tau decays. The studies presented include precise determinations of the strong coupling constant, tests of its flavour independence, tests of the SU(3) gauge structure of QCD, study of coherence effects, and measurements of single-particle inclusive distributions and two-particle correlations for many identified baryons and mesons.

44 data tables

Table 1

Charged particle sphericity distribution.

Table 2

Charged particle aplanarity distribution.

Table 3

Charged particle Thrust distribution.

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Studies of QCD in e+ e- --> hadrons at E(cm) = 130-GeV and 136-GeV.

The ALEPH collaboration Buskulic, D. ; De Bonis, I. ; Decamp, D. ; et al.

Z.Phys.C 73 (1997) 409-420, 1997.

Inspire Record 421546 DOI 10.17182/hepdata.47802

None

8 data tables

Table 1

Inclusive charged particle distribution as a function of XP.

Table 2

Inclusive charged particle distribution as a function of rapidity (YRAP).

Table 3

Inclusive charged particle distribution as a function of PT in the event plane.

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Production of K0 and Lambda in hadronic Z decays

The ALEPH collaboration Buskulic, D. ; Casper, D. ; De Bonis, I. ; et al.

Z.Phys.C 64 (1994) 361-374, 1994.

Inspire Record 375060 DOI 10.17182/hepdata.48239

Measurements of the inclusive cross-sections forK0 and Λ production in hadronic decays of the Z are presented together with measurements of two-particle correlations within pairs of Λ andK0. The results are compared with predictions from the hadronization models Jetset, based on string fragmentation, and Herwig, based on cluster decays. TheK0 spectrum is found to be harder than predicted by both models, while the Λ spectrum is softer than predicted. The correlation measurements are all reproduced well by Jetset, while Herwig misses some of the qualitative features and overestimates the size of the$\Lambda \bar \Lambda $ correlation. Finally, the possibility of Bose-Einstein correlation in theKS0KS0 system is discussed.

7 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Inclusive charged hadron and K0 production in two photon interactions

Cords, D. ; Boyer, J. ; Butler, F. ; et al.

Phys.Lett.B 302 (1993) 341-344, 1993.

Inspire Record 340849 DOI 10.17182/hepdata.28958

The inclusive transverse momentum distributions of charged hadrons and K 0 's produced in tagged photon-photon collisions, are measured and compared to model calculations up to a p T of 5 GeV/ c . The relative abundance of K 0 's favor the inclusion of charm.

1 data table

Table 1

Data read from graph.

rivet Analysis
Multi - Hadronic Events at E(c.m.) = 29-GeV and Predictions of QCD Models from E(c.m.) = 29-GeV to E(c.m.) = 93-GeV

Petersen, A. ; Abrams, G.S. ; Adolphsen, Chris ; et al.

Phys.Rev.D 37 (1988) 1, 1988.

Inspire Record 246184 DOI 10.17182/hepdata.4114

Multihadronic e+e− annihilation events at a center-of-mass energy of 29 GeV have been studied with both the original (PEP 5) Mark II and the upgraded Mark II detectors. Detector-corrected distributions from global shape analyses such as aplanarity, Q2-Q1, sphericity, thrust, minor value, oblateness, and jet masses, and inclusive charged-particle distributions including x, rapidity, p⊥, and particle flow are presented. These distributions are compared with predictions from various multihadron event models which use leading-logarithmic shower evolution or QCD matrix elements at the parton level and string or cluster fragmentation for hadronization. The new generation of parton-shower models gives, on the average, a better description of the data than the previous parton-shower models. The energy behavior of these models is compared to existing e+e− data. The predictions of the models at a center-of-mass energy of 93 GeV, roughly the expected mass of the Z0, are also presented.

74 data tables

Table 1

Aplanarity distribution.

Table 2

QX Distribution(QX=SQRT(3)*(Q3-Q2)).

Table 3

The (Q2-Q1) distribution.

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Direct Photon Pair Production From Pions and Protons at 200-{GeV}/$c$

The NA3 collaboration Badier, J. ; Bardadin-Otwinowska, M. ; Bemporad, C. ; et al.

Phys.Lett.B 164 (1985) 184-188, 1985.

Inspire Record 217947 DOI 10.17182/hepdata.30329

We present results from a direct photon pair search performed with the NA3 spectrometer, using incident positive and negative beams at 200 GeV/ c interacting with a carbon target. The experiment is sensitive to photons with p T >1.8 GeV / c and −0.4⩽y ∗ ⩽1.0 , one in each arm of the apparatus. A 3 standard deviation signal is seen in τ − and p interactions. The cross section is higher than the second order QCD calculations, but systematic errors are large.

1 data table

Table 1

No description provided.