HEPData Search

Showing 8 of 18 results

rivet Analysis
Production of J / psi mesons from chi(c) meson decays in p anti-p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.

Phys.Rev.Lett. 79 (1997) 578-583, 1997.

Inspire Record 440446 DOI 10.17182/hepdata.42231

We have measured the fraction of J/ψ mesons originating from χc meson decays in pp¯ collisions at s=1.8TeV. The fraction, for PTJ/ψ>4.0GeV/c and |ηJ/ψ|<0.6, not including contributions from b flavored hadrons, is 29.7%±1.7%(stat)±5.7%(syst). We have determined the cross sections for J/ψ mesons originating from χc decays and for directly produced J/ψ mesons. We have found that direct J/ψ production is in excess of the prediction of the color singlet model by the same factor found for direct ψ(2S) production.

4 data tables

Table 1

Fraction of J/PSI mesons from CHI/C decays, excluding the the contributions from b-hadron decay.

Table 2

Differential cross section for J/PSI's directly produced (ie excluding CHI/C and PSI/(25) decay contribution to the prompt production cross section). RE = PBAR P --> J/PSI X.

Table 3

Differential cross section for J/PSI's produced in CHI/C decays.

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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Previously published and as yet unpublished QCD results obtained with the ALEPH detector at LEP1 are presented.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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Measurement of the B meson differential cross-section, d sigma / d p(T), in p anti-p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Albrow, M.G. ; Amendolia, S.R. ; et al.

Phys.Rev.Lett. 75 (1995) 1451-1455, 1995.

Inspire Record 393552 DOI 10.17182/hepdata.42432

This paper presents the first direct measurement of the $B$ meson differential cross section, $d\sigma/dp_T$, in $p\overline{p}$ collisions at $\sqrt{s}=1.8$ TeV using a sample of $19.3 \pm 0.7$ pb$~{-1}$ accumulated by the Collider Detector at Fermilab (CDF). The cross section is measured in the central rapidity region $|y| < 1$ for $p_T(B) > 6.0$ GeV/$c$ by fully reconstructing the $B$ meson decays $B~{+}\rightarrow J/\psi K~{+}$ and $B~{0}\rightarrow J/\psi K~{*0}(892)$, where $J/\psi \rightarrow \mu~+\mu~-$ and $K~{*0} \rightarrow K~+ \pi~-$. A comparison is made to the theoretical QCD prediction calculated at next-to-leading order.

3 data tables

Table 1

Charged B meson cross section.

Table 2

Average B meson cross section (including charged and neutral).

Table 3

Total integrated B meson cross section above 6 GeV.

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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DOUBLE PROMPT PHOTON PRODUCTION AT HIGH TRANSVERSE MOMENTUM BY pi- ON PROTONS AT 280-GeV/c

The WA70 collaboration Bonvin, E. ; Bopp, R. ; Carroll, L.J. ; et al.

Z.Phys.C 41 (1989) 591, 1989.

Inspire Record 265091 DOI 10.17182/hepdata.15470

A search for pairs of highpT prompt photons produced in hydrogen by a 280 GeV/c incidentπ- beam has been carried out using a fine-grained electromagnetic calorimeter and the Omega spectrometer at the CERN SPS. Clear evidence for the existence of such events is found with a six standard deviation signal forpT>3.0 GeV/c. The cross-sections are consistent with beyond leading order QCD calculations. A discussion on the determination of αs is also presented.

2 data tables

Table 1

PT is the transverse momentum of either of the two photons.

Table 2

PT is the transverse momentum of either of the two photons.

Hadron Production at Transverse Momenta From 0.5-{GeV} Up to 2.2-{GeV}/c in Proton Proton Collisions at 70-{GeV}

Abramov, V.V. ; Alekseev, A.V. ; Baldin, B.Yu. ; et al.

Sov.J.Nucl.Phys. 31 (1980) 484, 1980.

Inspire Record 143797 DOI 10.17182/hepdata.34474

The cross sections for π ± , K ± , p, and p production in pp collisions have been measured at transverse momenta from 0.48 up to 2.21 GeV/ c at 70 GeV. The data are compared with results obtained at lower and higher proton energies and also with the quantum chromodynamics parton model (QPM) calculations. Common behaviour of the cross sections of the form g(p ⊥ )⨍(x ⊥ ) in the energy range above 200 GeV does not take place at lower energies. Qualitatively QPM fits the data and the best agreement is for π + / π − and K + / π + ratios.

7 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.