Amalskii, G.M.
DSIG/DZ
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Measurements of inelastic J/psi and psi' photoproduction at HERA.

The ZEUS collaboration Chekanov, S. ; Krakauer, D. ; Magill, S. ; et al.
Eur.Phys.J.C 27 (2003) 173-188, 2003.
Inspire Record 601166 DOI 10.17182/hepdata.46546

The cross sections for inelastic photoproduction of J/psi and psi' mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 38.0 pb-1. The events were required to have 0.1 < z < 0.9 and 50 < W < 180 GeV, where z is the fraction of the incident photon energy carried by the J/psi in the proton rest frame and W is the photon-proton centre-of-mass energy. The psi' to J/psi cross-section ratio was measured in the range 0.55 < z < 0.9. The J/psi data, for various ranges of transverse momentum, are compared to theoretical models incorporating colour-singlet and colour-octet matrix elements. Predictions of a next-to-leading-order colour-singlet model give a good description of the data, although there is a large normalisation uncertainty. The J/psi helicity distribution for z > 0.4 is compared to leading-order QCD predictions.

10 data tables
Table 1

Measurment of the total cross section, with various PT thresholds, in the high Z > 0.9 region.

Table 2

Ratio of cross section for PSI(2S) to J/PSI production. as a function of PT. Statistical errors only.

Table 3

Ratio of cross section for PSI(2S) to J/PSI production. as a function of W. Statistical errors only.

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Measurement of inelastic J / psi photoproduction at HERA

The ZEUS collaboration Breitweg, J. ; Derrick, M. ; Krakauer, D. ; et al.
Z.Phys.C 76 (1997) 599-612, 1997.
Inspire Record 446830 DOI 10.17182/hepdata.44512

We present a measurement of the inelastic, non diffractive J/$\psi$ photoproduction cross section in the reaction $e^{+} p \to e^{+} {J}/\psi X$ with the ZEUS detector at HERA. The J/$\psi$ was identified using both the $\mu^{+}\mu^{-}$ and $e^{+}e^{-}$ decay channels and events were selected within the range $0.4 1$ GeV$^2$, NLO calculations of the photon-gluon fusion process based on the colour-singlet model are in good agreement with the data. The predictions of a specific leading order colour-octet model, as formulated to describe the CDF data on J/$\psi$ hadroproduction, are not consistent with the data.

13 data tables
Table 1

Cross section for the MU+ MU- decay channel.

Table 2

Cross section for the MU+ MU- decay channel.

Table 3

Cross section for the MU+ MU- decay channel.

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Prompt Electron Production From Delco at {PEP}

The DELCO collaboration Pal, T. ; Atwood, W.B. ; Barish, B.C. ; et al.
Phys.Rev.D 33 (1986) 2708, 1986.
Inspire Record 226886 DOI 10.17182/hepdata.23516

We report final results on prompt electron production in hadronic events from e+e− annihilations at √s =29 GeV, obtained with the DELCO detector at the SLAC storage ring PEP. We find the semielectronic branching ratios of charm and bottom quarks to be B(c→se+νe)=(11.6−0.9 +1.1)% and B(b→ce−ν¯e)=(14.9−1.9 +2.2)% respectively. These results, from the complete data set, are consistent with an earlier analysis of partial data and indicate hard fragmentation functions for both c and b quarks, with mean values 〈zc〉=0.59±0.04 and 〈zb〉=0.72±0.05. The errors indicated here are a combination of statistical and systematic uncertainties.

4 data tables
Table 1

Axis error includes +- 0.0/0.0 contribution (NOT GIVEN).

Table 2

Axis error includes +- 0.0/0.0 contribution (NOT GIVEN).

Table 3

Axis error includes +- 0.0/0.0 contribution (NOT GIVEN).

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