HEPData Search

A measurement of the single-spin asymmetry A N in p↑ + p→ π 0 + X at 200 GeV with x F = 0 shows a transition in the production process from a “ low -x T ” regime with A N = 0, through an intermediate region of negative asymmetry, to a “ high -x T ” regime with A N > 0.3. This transition occurs at x T ≈ 0.4 and is consistent with x T -scaling of A N in pion production using polarized beams or targets from √− s =5.2 to 19.4 GeV. Results for A N in η production by polarized protons and in π 0 production by polarized antiprotons are also presented.

3 data tables

Table 1

Statistical errors only.

Table 2

Statistical errors only.

Table 3

Statistical errors only.

Strangeness enhancement in central S + S collisions at 200-GeV/nucleon.

The NA35 collaboration Baechler, J. ; Bartke, J. ; Bialkowska, H. ; et al.

Nucl.Phys.A 525 (1991) 221C-226C, 1991.

Inspire Record 328899 DOI 10.17182/hepdata.36820

None

4 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Hard exclusive hadron nucleon scattering and color transparency

Heppelmann, S. ; Wu, J.Y. ; Appel, R. ; et al.

Nucl.Phys.A 527 (1991) 581C-583C, 1991.

Inspire Record 327578 DOI 10.17182/hepdata.36761

We present preliminary results on the measurement of a variety of exclusive hadron interactions at center of mass scattering angles of 90°. Data are also presented which show the relative transparency of nuclei to πp and pp elastic scattering in this kinematic range.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

Measurement of the production of high mass gamma gamma, pi0 pi0, and gamma pi0 pairs in pi- p, pi+ p, and p p collisions at 300-GeV/c

De Marzo, C. ; De Palma, M. ; Favuzzi, C. ; et al.

Phys.Rev.D 42 (1990) 748-758, 1990.

Inspire Record 303958 DOI 10.17182/hepdata.22851

The NA24 experiment at CERN investigated inclusive γγ, π0π0, and γπ0 final states in the mass range between 4 and 9 GeV/c2 produced in π−p, π+p, and pp reactions at a c.m.-system energy s=23.7 GeV. The π0π0 cross sections agree well with expectations of the quark-parton model. For γπ0 production in π−p and pp reactions, a clear signal is observed and cross sections are shown. The production of γγ events was observed with a statistical significance of 2.9σ in π−p reactions. The cross section is in agreement with a higher-order QCD prediction.

5 data tables

Table 1

Cross sections are averaged over the transverse momentum differences up to a value which is 1.10 GeV for all points except the first two which are 0.5 and 0.75 GeV respectively.

Table 2

No description provided.

Table 3

Maximum accepted transverse momentum difference of pi0 pair is 1 GeV. Inclusive cross section integrated over the total geometrical acceptance of the detector.

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Proton proton bremsstrahlung at 280-MeV

Michaelian, K. ; Kitching, P. ; Hutcheon, D.A. ; et al.

Phys.Rev.D 41 (1990) 2689-2704, 1990.

Inspire Record 304884 DOI 10.17182/hepdata.23001

A proton-proton bremsstrahlung experiment has been carried out at TRIUMF using a 280-MeV polarized proton beam impinging on a liquid-hydrogen target. All three outgoing particles were detected: the higher-energy proton in a magnetic spectrometer, the lower-energy proton with plastic scintillators, and the photon in lead-glass Cherenkov detectors. The experiment shows the first unambiguous evidence for off-shell effects in the free nucleon-nucleon interaction, in that the analyzing powers disagree strongly with the predictions of the soft-photon approximation (which incorporates only on-shell information) but are consistent with the results of calculations using the Bonn and Paris potentials.

8 data tables

Table 1

Estimated scale uncertainty is 1.5 pct.

Table 2

Estimated scale uncertainty is 1.5 pct.

Table 3

Estimated scale uncertainty is 1.5 pct.

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Single Spin Asymmetry in Inclusive Reactions Polarized $P$, $P$ Goes to $\pi^+$, $\pi^-$, and $P$ at High $P$(t) at 13.3-{GeV}/$c$ and 18.5-{GeV}/$c$

Saroff, S. ; Baller, B.R. ; Blazey, G.C. ; et al.

Phys.Rev.Lett. 64 (1990) 995, 1990.

Inspire Record 26394 DOI 10.17182/hepdata.19960

Data are presented for the left-right asymmetry in inclusive production of π+, π−, and p with proton beams (polarized normal to the scattering plane) of 13.3 and 18.5 GeV/c incident on a LH2 target. At both energies the asymmetry in π+ production grows steadily to about 25% near the kinematic limit, whereas the π− and p asymmetries are consistent with zero over the measured range of pt, 1.1–2.2 GeV/c.

18 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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A Study of the Centrally Produced $K^0 \bar{K}^$0 Final State in the Reaction $p p \to p$(f) ($K^+ K^- \pi^+ \pi^-$) $p(s$) at 300-{GeV}/$c$

The WA76 collaboration Armstrong, T.A. ; Benayoun, M. ; Beusch, W. ; et al.

Z.Phys.C 46 (1990) 405-410, 1990.

Inspire Record 287163 DOI 10.17182/hepdata.15199

The reactionpp→pf(K+K-π+π-)ps, where theK+K− π+π- system is centrally produced, has been studied at 300 GeV/c. TheK*0$K^{*0} \bar K^{*0} $ final state has been observed and the cross sections for its central production are found to be the same at 300 and 85 GeV/c. TheK*0$K^{*0} \bar K^{*0} $ final state appears to be produced as a non-resonant threshold enhancement.

2 data tables

Table 1

No description provided.

Table 2

Cross sections for centrally produced vector-vector final states with mass greater than the phi-phi production threshold.

High $p_T \gamma$ and $\pi^0$ Production, Inclusive and With a Recoil Hadronic Jet, in $p p$ Collisions at $\sqrt{s}=63$-{GeV}

The Axial Field Spectrometer collaboration Akesson, T. ; Albrow, M.G. ; Almehed, S. ; et al.

Sov.J.Nucl.Phys. 51 (1990) 836-845, 1990.

Inspire Record 281284 DOI 10.17182/hepdata.48816

None

3 data tables

Table 1

Errors are combined statistical and systematic.

Table 2

Errors are combined statistical and systematic.

Table 3

Errors are combined statistical and systematic.

Evidence for New States Produced in the Central Region in the Reaction $p p \to p$(f) ($\pi^+ \pi^- \pi^+ \pi^-$) $p(s$) at 300-{GeV}/$c$

The WA76 collaboration Armstrong, T.A. ; Benayoun, Maurice ; Beusch, W. ; et al.

Phys.Lett.B 228 (1989) 536-542, 1989.

Inspire Record 280165 DOI 10.17182/hepdata.29783

The reaction pp→p f ( π + π − π + π − )p s , where the π + π − π + π − system is centrally produced, has been studied at 300 GeV/ c in an experiment designed to search for gluonic states. The π + π − π + π − mass spectrum shows evidence for the f 1 (1285) with a mass of 1281±1 MeV and a width of 31±5 MeV. In addition there is evidence for two new enhancements at masses of 1449±4 and 1901±13 MeV with widths of 78±18 and 312±61 MeV respectively. An analysis of the state at 1.45 GeV indicates that it is not a π + π − π + π − decay mode of the f 1 (1420) or ι η(1440) .

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Comparison of Spin Asymmetries and Cross Sections in $\pi^0$ Production by 200 GeV Polarized Antiprotons and Protons

High $\chi_t$ Single Spin Asymmetry in $\pi^0$ and $\eta$ Production at $\chi_F$ = 0 by 200 GeV Polarized Antiprotons and Protons

Strangeness enhancement in central S + S collisions at 200-GeV/nucleon.

Hard exclusive hadron nucleon scattering and color transparency

Measurement of the production of high mass gamma gamma, pi0 pi0, and gamma pi0 pairs in pi- p, pi+ p, and p p collisions at 300-GeV/c

Proton proton bremsstrahlung at 280-MeV

Single Spin Asymmetry in Inclusive Reactions Polarized $P$, $P$ Goes to $\pi^+$, $\pi^-$, and $P$ at High $P$(t) at 13.3-{GeV}/$c$ and 18.5-{GeV}/$c$

A Study of the Centrally Produced $K^0 \bar{K}^$0 Final State in the Reaction $p p \to p$(f) ($K^+ K^- \pi^+ \pi^-$) $p(s$) at 300-{GeV}/$c$

High $p_T \gamma$ and $\pi^0$ Production, Inclusive and With a Recoil Hadronic Jet, in $p p$ Collisions at $\sqrt{s}=63$-{GeV}

Evidence for New States Produced in the Central Region in the Reaction $p p \to p$(f) ($\pi^+ \pi^- \pi^+ \pi^-$) $p(s$) at 300-{GeV}/$c$