HEPData Search

A bubble-chamber experiment based on 304 000 events of p¯p interactions at 2.32 GeV/c is described. The film was automatically scanned and measured by the POLLY II system. Details of the data-analysis methods are given. We report results on cross sections for constrained final states, tests of C invariance, and inclusive pion and ρ0 multiplicity parameters for annihilation final states.

2 data tables

Table 1

Axis error includes +- 4/4 contribution.

Table 2

Axis error includes +- 4/4 contribution.

Comparative Study of rho0, omega, K* (890) and anti-K* (890) Production by Charge Exchange

Wicklund, A.B. ; Ayres, D.S. ; Diebold, R. ; et al.

Phys.Rev.D 17 (1978) 1197, 1978.

Inspire Record 120816 DOI 10.17182/hepdata.24436

We present cross sections and density-matrix elements from a high-statistics study of the reactions π−p→ρ0n, K−p→K¯*0(890)n, and K+n→K*0(890)p, at 3, 4, and 6 GeV/c and four-momentum transfer squared to the recoil nucleon −t<~0.9 GeV2. The experiment was carried out at the Argonne Zero Gradient Synchrotron using the effective-mass spectrometer. In the same experiment, we have measured the ρ−ω interference cross sections by comparison of the two reactions π−p→π−π+n and π+n→π+π−p, to which the interference terms contribute with opposite signs. We examine the systematics of ρ0 production: In the s channel we find little shrinkage with energy of the helicity-0 cross sections, which are presumably dominated by π exchange; the helicity-1 cross sections exhibit considerable shrinkage for unnatural-parity exchange, and antishrinkage for natural-parity exchange. The K*0 and K¯*0 production observables exhibit significant differences, especially in the helicity-1 states. These differences are due to interference between even- and odd-G-parity exchange amplitudes and they are related by SU(3) symmetry to ρ−ω interference effects and to the ρ0 and ω production observables. It is shown that exchange-degeneracy-breaking effects satisfy SU(3) symmetry and can be explained qualitatively in the frame-work of SU(3)-symmetric, strongly absorbed Regge-pole models. The results of our amplitude analysis are compared with previous phenomenological analyses and model predictions.

9 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Measurement of $\phi$ Production in Proton - Nucleus Collisions at 400 GeV/c

Akerlof, C.W. ; Alley, P. ; Bintinger, D. ; et al.

Phys.Rev.Lett. 39 (1977) 861, 1977.

Inspire Record 120734 DOI 10.17182/hepdata.20951

We have measured the invariant cross section for inclusive ϕ production in proton-nucleus collisions at 400 GeV/c near Feynman x=0. For transverse momenta in the range between 0.8 and 3.5 GeV/c the ratio of ϕ to π− rises from 1 to 7%. We also report on correlations with particles opposite the ϕ in the center-of-mass system as they relate to the Okubo-Zweig-Iizuka rule.

1 data table

Table 1

No description provided.

Inclusive anti-K* (890) Production in pi- p Interactions at 16-GeV/c

The Bari-Bonn-CERN-Daresbury-Glasgow-Liverpool-Milan-Vienna collaboration Evangelista, C. ; Ghidini, B. ; Palano, A. ; et al.

Phys.Lett.B 70 (1977) 373, 1977.

Inspire Record 120738 DOI 10.17182/hepdata.48966

Inclusive K ∗0 production is studied in π − p interactions at 16 GeV/ c with x ϝ > 0.2. The K ∗0 is found to be pre-dominantly centrally produced with cross section σ( K ∗0 ) = (72 ± 12) μb for x ϝ > 0.2 and compares closely to data on K ∗0 production in π + p interactions at the same energy.

3 data tables

Table 1

No description provided.

Table 2

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Table 3

No description provided.

Inclusive phi Production in pi- p Interactions at 16-GeV/c

The Bari-Bonn-CERN-Daresbury-Glasgow-Liverpool-Milan-Vienna collaboration Ghidini, B. ; Navach, F. ; Palano, A. ; et al.

Phys.Lett.B 68 (1977) 186, 1977.

Inspire Record 119248 DOI 10.17182/hepdata.48929

Inclusive φ production is studied in π − p collisions at 16 GeV/ c . The φ cross section for Feynman variable x φ > 0.2 is found to be (15.5 ± 3.6) μb. This leads to an extrapolated cross section of (29.9 ± 7.0) μb for x φ > 0.0. Fitting the momentum transfer squared distribution of the φ to the form e −bp 2 T gives an average slope of b = (2.4 ± 0.3) (GeV/ c −2 for x φ > 0.5.

4 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

DATA OBTAINED FROM FIGURE BY A.A. LEBEDEV.

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Phi-Meson Production in the Reactions pi+- n --> K- K+ n at 6-GeV/c

Cohen, Daniel H. ; Ayres, D.S. ; Diebold, R. ; et al.

Phys.Rev.Lett. 38 (1977) 269, 1977.

Inspire Record 110508 DOI 10.17182/hepdata.21019

A sample of 1200 ϕ mesons produced in the Zweig-rule-forbidden reactions π±N→ϕN shows a flat t distribution (slope=1.7 ± 0.2 GeV−2) and a cross section suppressed by 0.0032±0.0004 relative to π−p→ωn. Natural-parity-exchange ω and ϕ production have similar t dependences, while ω and ϕ production by unnatural-parity exchange differ markedly. Interference between the ϕ and the underlying K¯K S wave indicates substantial nucleon-spin incoherence between the amplitudes for ϕ and S-wave production.

3 data tables

Table 1

Axis error includes +- 10/10 contribution (RES-DEF(RES=PHI,BACK=CORRECTED)).

Table 2

Axis error includes +- 10/10 contribution (RES-DEF(RES=PHI,BACK=CORRECTED)).

Table 3

STATISTICAL ERRORS ONLY.

$\pi^{\pm} p$, $K^{\pm} p$, $pp$ and $p\bar{p}$ Elastic Scattering from 50-GeV/c to 175-GeV/c

The Fermilab Single Arm Spectrometer Group collaboration Ayres, D.S. ; Diebold, R. ; Maclay, G.J. ; et al.

Phys.Rev.D 15 (1977) 3105, 1977.

Inspire Record 110409 DOI 10.17182/hepdata.24653

The differential cross sections for the elastic scattering of π+, π−, K+, K−, p, and p¯ on protons have been measured in the t interval -0.04 to -0.75 GeV2 at five momenta: 50, 70, 100, 140, and 175 GeV/c. The t distributions have been parametrized by the quadratic exponential form dσdt=Aexp(B|t|+C|t|2) and the energy dependence has been described in terms of a single-pole Regge model. The pp and K+p diffraction peaks are found to shrink with α′∼0.20 and ∼0.15 GeV−2, respectively. The p¯p diffraction peak is antishrinking while π±p and K−p are relatively energy-independent. Total elastic cross sections are calculated by integrating the differential cross sections. The rapid decline in σel observed at low energies has stopped and all six reactions approach relatively constant values of σel. The ratio of σelσtot approaches a constant value for all six reactions by 100 GeV, consistent with the predictions of the geometric-scaling hypothesis. This ratio is ∼0.18 for pp and p¯p, and ∼0.12-0.14 for π±p and K±p. A crossover is observed between K+p and K−p scattering at |t|∼0.19 GeV2, and between pp and p¯p at |t|∼0.11 GeV2. Inversion of the cross sections into impact-parameter space shows that protons are quite transparent to mesons even in head-on collisions. The probability for a meson to pass through a proton head-on without interaction inelastically is ∼20% while it is only ∼6% for an incident proton or antiproton. Finally, the results are compared with various quark-model predictions.

31 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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$\pi^- p$ Interactions at 360-GeV/c: Measurement of the Total and Elastic Cross-Sections and the Charged Particle Multiplicity Distribution

Firestone, A. ; Anderson, E.W. ; Chang, V. ; et al.

Phys.Rev.D 14 (1976) 2902, 1976.

Inspire Record 3926 DOI 10.17182/hepdata.24670

In a sample of 108 563 pictures taken with the Fermilab 30-inch hydrogen bubble chamber, exposed to a 360-GeV/c π− beam, we have observed 19 453 interactions in a selected fiducial region. The observed charged multiplicity distribution has been corrected for the effects of scan efficiency, errors in prong count, missed close-in vees, secondary interactions, and neutron stars and for Dalitz pairs. The two-prong events have been corrected for losses at low −t. The total cross section is measured to be 25.25 ± 0.35 mb, and the elastic cross section is 3.61 ± 0.11 mb with an exponential slope of (8.82 ± 0.30) (GeV/c)−2. The average charged-particle multiplicity for inelastic events is 8.73 ± 0.04, and the second moment f2 is measured to be 9.83 ± 0.23.

2 data tables

Table 1

SYSTEMATIC CORRECTIONS INCLUDED IN ERRORS.

Table 2

FROM FIT, FORWARD D(SIG)/DT = 31.84 +- 0.68 MB/GEV**2, AND AGREES WITH OPTICAL POINT FROM MEASURED TOTAL CROSS SECTIONS.

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Production of phi and f' in 10-GeV/c K- p Interactions

Observation of the Reaction pi- p --> anti-p d at 10-GeV/c and 16-GeV/c

anti-p p Interactions at 2.32-GeV/c

Comparative Study of rho0, omega, K* (890) and anti-K* (890) Production by Charge Exchange

Measurement of $\phi$ Production in Proton - Nucleus Collisions at 400 GeV/c

Inclusive anti-K* (890) Production in pi- p Interactions at 16-GeV/c

Inclusive phi Production in pi- p Interactions at 16-GeV/c

Phi-Meson Production in the Reactions pi+- n --> K- K+ n at 6-GeV/c

$\pi^{\pm} p$, $K^{\pm} p$, $pp$ and $p\bar{p}$ Elastic Scattering from 50-GeV/c to 175-GeV/c

$\pi^- p$ Interactions at 360-GeV/c: Measurement of the Total and Elastic Cross-Sections and the Charged Particle Multiplicity Distribution