Dukes, E.C.
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Measurement of the inclusive J / psi production cross-sections in anti-p p and p p collisions at s**(1/2) = 24.3-GeV

The UA6 collaboration Morel, C. ; Bernasconi, A. ; Breedon, R.E. ; et al.
Phys.Lett.B 252 (1990) 505-510, 1990.
Inspire Record 300180 DOI 10.17182/hepdata.29505

The inclusive cross section times branching ratio for J/ψ→e + e − has been measured in the forward region in the UA6 experiment for p p and pp collisions at √ s = 24.3 GeV. The ratio of the pp to p p cross sections is found to be 0.76 ± 0.14 ± 0.06. This demonstrates that gluon-gluon fusion dominates over quark-antiquark annihilation in the formation of the c c state.

3 data tables match query
Table 1

Extrapolation to full forward hemisphere (yrap > 0.0) uses the Bourquin-Gaillard parametrization (NP B114(76)334).

Table 2

Extrapolation to full forward hemisphere (yrap > 0.0) uses the Bourquin-Gaillard parametrization (NP B114(76)334).

Table 3

No description provided.


A New determination of alpha(s) using direct photon production cross-sections in p p and anti-p p collisions at S**(1/2) = 24.3-GeV

The UA6 collaboration Werlen, M. ; Ballocchi, G. ; Breedon, R.E. ; et al.
Phys.Lett.B 452 (1999) 201-206, 1999.
Inspire Record 496157 DOI 10.17182/hepdata.34551

Direct photon production cross sections obtained in high statistics p ̄ p and pp collisions at s =24.3 GeV at the CERN SPS are used in a next-to-leading order QCD analysis. From the cross section difference σ( p ̄ p → γX)−σ(pp → γX) and quark distributions measured in deep inelastic scattering, a determination of the strong coupling constant, α s , is performed via a measurement of Λ (4) MS . This measurement yields a value Λ (4) MS = 210±22 ( stat. )±44 ( syst. ) +105 −36 ( theo. ) MeV. The corresponding value of α s expressed at M 2 Z is α s (M 2 Z )=0.1112 ±0.0016 ( stat. ) ±0.0033 ( syst. ) +0.0077 −0.0034 ( theo. ) .

1 data table match query
Table 1

Value of LAMBDA(MSBAR) and ALPHAS at MZ**2 deduced from the difference in the pbar and p direct photon cross sections. The second systematic error is due to the uncertainties in the theory.


A Measurement of the Inclusive $\pi^0$ and $\eta$ Production Cross-sections at High $p_T$ in $p \bar{p}$ and $p p$ Collisions at $\sqrt{s}=24$.3-{GeV}

The UA6 & CERN-Lausanne-Michigan-Rockefeller collaborations Antille, J. ; Baumann, S. ; Bernasconi, A. ; et al.
Phys.Lett.B 194 (1987) 568, 1987.
Inspire Record 247579 DOI 10.17182/hepdata.30119

Inclusive π 0 and η production at large transverse momentum were studied in both p̄p and pp interactions at √ s = 24.3 GeV. The experiment was performed using an internal molecular hydrogen gas jet target in the CERN SPS collider. No significant differences between production in p̄p and pp were observed in the transverse momentum range 2.5 < P T < 5.1 GeV/ c .

3 data tables match query
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Polarization of Sigma0 hyperons in inclusive production from 28.5-GeV/c protons on beryllium

Dukes, E.C. ; Overseth, O.E. ; Bunce, G.M. ; et al.
Phys.Lett.B 193 (1987) 135-139, 1987.
Inspire Record 249257 DOI 10.17182/hepdata.30125

The polarization of Σ 0 hyperons produced in an inclusive reactons hasbeen measured for the first time. From a sample of 11 000 events produced by 28.5 GeV/ c ptorons in the reaction p+ Be → Σ 0 +X, the Σ 0 polarization has a value of +0.28±0.13 at p t =1.01 GeV/ c and x f =0.60. The polarization of 53 000 Λ hyperons produced from 28.5 Gev/ c protons inthe reaction p+Be→ Λ +X has been measured in the kinematic range 0.64< p t <1.14 GeV/ c and 0.42< x f <0.62. The average Λ polarization is found to be −0.188±0.024, consistent with previous results.

2 data tables match query
Table 1

No description provided.

Table 2

No description provided.


Precise Comparison of Anti-proton - Proton and Proton Proton Forward Elastic Scattering at $\sqrt{s}=24$.3-{GeV}

The UA6 collaboration Breedon, R.E. ; Chapin, T.J. ; Cool, R.L. ; et al.
Phys.Lett.B 216 (1989) 459-465, 1989.
Inspire Record 267044 DOI 10.17182/hepdata.29854

We report results from a measurement of antiproton-proton and proton-proton small-angle elastic scattering at √ s = 24.3 GeV in the range 0.001 ⩽ | t | ⩽ 0.06 (GeV/ c ) 2 . The measurement was performed at the CERN p p Collider by using silicon detectors to observe protons recoiling from a hydrogen cluster-jet target intercepting the stored p and p beams. Fits to the measured differential cross sections yield the ratio of the real to the imaginary part of the forward nuclear scattering amplitude ρ and the nuclear slope parameter b for both p p and pp. We find that the difference Δρ = ρ ( p p ) − ρ( pp ) = 0.031 ± 0.010 agrees with conventional fits and disagrees with the “odderon” fit designed to accommodate the recent UA4 measurement of ρ( p p) at 546 GeV.

3 data tables match query
Table 1

Data requested from authors.

Table 2

No description provided.

Table 3

Nuclear slopes fixed to world average.


Direct Photon Production in Proton - Anti-proton Interactions at $\sqrt{s}=24$.3-{GeV}

The UA6 collaboration Bernasconi, A. ; Breedon, R.E. ; Camilleri, L. ; et al.
Phys.Lett.B 206 (1988) 163-168, 1988.
Inspire Record 261244 DOI 10.17182/hepdata.29982

Direct photons have been studied in pp̄ interactions at √ s = 24.3 GeV and in the transverse momentum ( p T ) range 3–7 GeV/ c (0.25 < x T < 0.58). The experiment was performed using an internal H 2 cluster the target in the CERN pp̄ Collider. The measured invariant cross section is compared with recent theoretical predictions.

2 data tables match query
Table 1

No description provided.

Table 2

No description provided.


Direct photon production in anti-p p and p p interactions at s**(1/2) = 24.3-GeV

The UA6 collaboration Sozzi, G. ; Ballocchi, G. ; Bernasconi, A. ; et al.
Phys.Lett.B 317 (1993) 243-249, 1993.
Inspire Record 358422 DOI 10.17182/hepdata.28782

Inclusive direct photon invariant cross sections have been measured in both p p and pp collisions at √ s = 24.3 GeV at the CERN SPS, permitting the first measurement of the difference of the p p and pp cross sections. The direct photon cross section in p p collisions has been found to be systematically larger than that in pp collisions, which indicates a significant contribution of the q q annihilation term as predicted by theoretical calculations.

4 data tables match query
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Hadroproduction of the chi1 and chi2 states of charmonium in 800-GeV/c proton silicon interactions.

The E771 collaboration Alexopoulos, T. ; Antoniazzi, L. ; Arenton, M. ; et al.
Phys.Rev.D 62 (2000) 032006, 2000.
Inspire Record 504991 DOI 10.17182/hepdata.41516

The cross sections for the hadroproduction of the Chi1 and Chi2 states of charmonium in proton-silicon collisions at sqrt{s}=38.8 GeV have been measured in Fermilab fixed target Experiment 771. The Chi states were observed via their radiative decay to J/psi+gamma, where the photon converted to e+e- in the material of the spectrometer. The measured values for the Chi1 and Chi2 cross sections for x_F>0 are 263+-69(stat)+-32(syst) and 498+-143(stat)+-67(syst) nb per nucleon respectively. The resulting sigma(Chi1}/sigma(Chi2) ratio of 0.53+-0.20(stat)+-0.07(syst), although somewhat larger than most theoretical expectations, can be accomodated by the latest theoretical estimates.

1 data table match query
Table 1

No description provided.


Measurements of Production Polarization and Decay Asymmetry for $\Xi^-$ Hyperons

Rameika, R. ; Beretvas, A. ; Deck, L. ; et al.
Phys.Rev.D 33 (1986) 3172-3179, 1986.
Inspire Record 233005 DOI 10.17182/hepdata.23517

The polarization of Ξ− hyperons produced by 400-GeV protons in the reaction p+Be→Ξ−+X has been measured as a function of momentum at two production angles. The average polarization for the full sample (192 110 events) was -0.108±0.007. Comparisons are made with polarization measurements for other hyperons produced under similar conditions. From the same data, αΛαΞ was measured to be -0.303±0.004±0.004, where αΛ is the asymmetry parameter in the decay Λ→pπ−, αΞ is the asymmetry parameter in the decay Ξ−→Λπ−, and the uncertainties are statistical and systematic, respectively. This yields αΞ=-0.472±0.006±0.011, where the systematic uncertainty is dominated by the uncertainty in αΛ. An updated test of the ΔI=1/2 rule in Ξ decay is presented.

2 data tables match query
Table 1

No description provided.

Table 2

No description provided.


Direct photon cross sections in proton proton and antiproton proton interactions at s**(1/2) = 24.3-GeV.

The UA6 collaboration Ballocchi, G ; Breedon, R.E ; Camilleri, L ; et al.
Phys.Lett.B 436 (1998) 222-230, 1998.
Inspire Record 476703 DOI 10.17182/hepdata.49311

We report results on inclusive direct photon ( γ ), π 0 , and η production in both pp and p̄p interactions at s =24.3 GeV in the transverse momentum range 4.1≤ p T ≤7.7 GeV/ c and rapidity range −0.1≤ y ≤0.9. The data were collected between 1988 and 1990 by the UA6 experiment at CERN, which employed an internal H 2 gas jet target in the Sp̄pS collider. The inclusive direct photon cross sections and the cross section difference σ( p p )−σ( pp ) expressed as functions of p T ( γ ) are compared with next-to-leading order QCD predictions.

1 data table match query
Table 1

PI0 cross sections. Direct photon cross section and pbar-p/p-p difference.