J / psi and psi (2S) production 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) 572-577, 1997.
Inspire Record 440101 DOI 10.17182/hepdata.42223

We present a study of J/ψ and ψ(2S) production in pp¯ collisions, at s=1.8TeV with the CDF detector at Fermilab. The J/ψ and ψ(2S) mesons are reconstructed using their μ+μ− decay modes. We have measured the inclusive production cross section for both mesons as a function of their transverse momentum in the central region, |η|<0.6. We also measure the fraction of these events originating from b hadrons. We thus extract individual cross sections for J/ψ and ψ(2S) mesons from b-quark decays and prompt production. We find a large excess (approximately a factor of 50) of direct ψ(2S) production compared with predictions from the color singlet model.

5 data tables

Integrated cross sections.

Differential cross section times branching ratio for J/PSI's originating from b hadron decays.

Differential cross section times branching ratio for PSI(2S) originating from b hadron decays.

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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

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

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.

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

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Differential cross sections of D*-+ photoproduction in e p collisions at HERA.

The ZEUS collaboration Breitweg, J. ; Derrick, M. ; Krakauer, D. ; et al.
Phys.Lett.B 401 (1997) 192-206, 1997.
Inspire Record 441088 DOI 10.17182/hepdata.44632

Inclusive photoproduction of $\dspm$ in ep collisions at HERA has been measured with the ZEUS detector for photon-proton centre of mass energies in the range \linebreak \wrang and photon virtuality Q~2 < 4 \g2. The cross section $\sigma_{ep \to \ds X} $ integrated over the kinematic region \ptrangand \etarang is {\xsecs}. Differential cross sections as functions of $p_{\perp}~{\ds}$, $\eta~{\ds}$ and W are given. The data are compared with two next-to-leading order perturbative QCD predictions. For a calculation using a massive charm scheme the predicted cross sections are smaller than the measured ones. A recent calculation using a massless charm scheme is in agreement with the data.

6 data tables

Data from the (Kpi)pi channel.

Data from the (Kpipipi)pi channel.

Data from the (Kpi)pi channel.

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Mass dependence of pi0 production in heavy ion collisions at 1-A/GeV

Schwalb, O. ; Pfeiffer, M. ; Berg, F.-D. ; et al.
Phys.Lett.B 321 (1994) 20-25, 1994.
Inspire Record 376130 DOI 10.17182/hepdata.28781

The production of neutral pions has been studied in the reactions 40 Ar + nat Ca , 86 Kr + nat Zr and 197 Au + 197 Au at 1 A GeV. For high energy pions emitted from the heavier systems a steeper than linear rise of the pion multiplicity with the centrality of the reaction is observed, indicating a pion production process other than binary nucleon-nucleon collisions. At low transverse momenta an enhancement of the π 0 -multiplicity increasing with the mass of the collision system is found. Systematic discrepancies between the experimental results and recent BUU, QMD and Cascade calculations are discussed.

6 data tables

No description provided.

RESULTS OF AN EXTRAPOLATION TO THE FULL SOLID ANGLE TAKING THE EXPERIMENTALTEMPERATURES INTO ACCOUNT.

No description provided.

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A Measurement of single and double prompt photon production at the CERN anti-p p collider

The UA2 collaboration Alitti, J. ; Ambrosini, G. ; Ansari, R. ; et al.
Phys.Lett.B 288 (1992) 386-394, 1992.
Inspire Record 336186 DOI 10.17182/hepdata.29113

A measurement of the cross-sections for single and double prompt photon production in p p interactions at s = 630 GeV is presented. The data sample corresponds to an integrated luminosity of 13.2 pb −1 . The results are in good agreement with the predictions of perturbative QCD. The signal from double prompt photon production has a statistical significance of 4.3 standard deviations.

2 data tables

There is an overall systematic error of 9 pct not included in the table.

Errors quoted include statistical and all PT dependent systematic uncertainties. There is in addition a 6.8 pct overall normalization uncertainty.


A Study of multi - jet events at the CERN anti-p p collider and a search for double parton scattering

The UA2 collaboration Alitti, J. ; Ambrosini, G. ; Ansari, R. ; et al.
Phys.Lett.B 268 (1991) 145-154, 1991.
Inspire Record 317817 DOI 10.17182/hepdata.29361

A study of events containing at least four high transverse momentum jets and a search for double parton scattering (DPS) have been performed using data collected with the UA2 detector at the CERN p p Collider (√ s =630 GeV). The results are in good agreement with leading order QCD calculations. A value of σ DPS <0.82 nb at 95% confidence level (CL) is obtained for the DPS cross section.

3 data tables

Data requested from authors.

Uncorrected cross sections.

Upper limit to DPS contribution to 4JET production.


Observation of Xi- Production in $p \bar{p}$ Interactions at 540-{GeV} {CMS} Energy

The UA5 collaboration Alner, G.J. ; Alpgard, K. ; Anderer, P. ; et al.
Phys.Lett.B 151 (1985) 309-314, 1985.
Inspire Record 204764 DOI 10.17182/hepdata.30437

We have made the first observations of Ξ − production in p p interactions at √ s =540 GeV. In a sample of 6964 non single-diffractive events we observe 17 Ξ − decays with an estimated background of less than one event. This corresponds to 0.04 ± 0.01 Ξ − per event in the transverse momentum range p t >1.0 GeV/ c and in the pseudorapidity range |η| < 3.5. Assuming an exponential p t distribution, we find 〈 p t 〉=1.1 −0.2 +0.3 GeV/ c .

1 data table

No description provided.