Date

Test of S Channel Helicity Conservation in Inelastic $\rho^0$ Diffraction in 20-{GeV} Photoproduction

The SLAC Hybrid Facility Photon collaboration Abe, K. ; Bacon, T.C. ; Ballam, Joseph ; et al.
Phys.Rev.D 32 (1985) 2288, 1985.
Inspire Record 209692 DOI 10.17182/hepdata.23546

The reaction γp→ρfast0pπ+π− has been studied with the linearly polarized 20-GeV monochromatic photon beam at the SLAC Hybrid Facility to test the prediction of s-channel helicity conservation in inelastic diffraction for t’<0.4 (GeV/c)2. In a sample of 1934 events from this reaction, the ρ0 decay-angular distributions and spin-density-matrix elements are consistent with s-channel helicity conservation, the π+π− mass shape displays the same skewing as seen in the reaction γp→pπ+π−, and the pπ+π− mass distribution compares well and scales according to the vector dominance model with that produced in π±p→πfast±pπ+π−.

3 data tables

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SPIN DENSITY MATRIX ELEMENTS FOR THE DIFFRACTIVE RHO0 MESON FROM STUDY OF THE ANGULAR DISTRIBUTIONS. CORRECTION HAS BEEN MADE FOR THE (20 +- 5) PCT NON DIFFRACTIVE BACKGROUND IN THE FINAL DATA SAMPLE, ASSUMING IT TO HAVE AN ISOTOPIC ANGULAR DISTRIBUTION.


Study of the $\rho^\prime$ (1600) Mass Region Using $\gamma p \to \pi^+ \pi^- p$ at 20-{GeV}

The SLAC Hybrid Facility Photon collaboration Abe, K. ; Bacon, T.C. ; Ballam, Joseph ; et al.
Phys.Rev.Lett. 53 (1984) 751, 1984.
Inspire Record 201710 DOI 10.17182/hepdata.20387

We have observed the π+π− decay of the ρ′(1600) in the production reaction γp→ρ′p at 20 GeV. Using a calculation which takes into account the interference of the ρ′ with the ρ(770) and a Drell background, we find good evidence that this resonance is a radial excitation of the ρ(770). The background interference strongly distorts the angular distributions predicted by a purely s-channel helicity-conserving production mechanism. We measure m0=(1.55±0.07) GeV/c2 and Γ0=(0.28−0.08+0.03) GeV/c2.

4 data tables

SLOPE VARIATION WITH M(PI+ PI-) IN THE RANGE 0.4 TO 2.5 GEV.

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Measurement of $\omega$ Meson Photoproduction on Protons From 46 GeV to 180 GeV

Egloff, R.M. ; Davis, P.J. ; Luste, G.J. ; et al.
Phys.Rev.Lett. 43 (1979) 1545, 1979.
Inspire Record 142364 DOI 10.17182/hepdata.3122

Elastic ω-meson photoproduction on protons has been measured from 46 to 180 GeV. The cross section is approximately constant with photon energy and averages 1.10 ± 0.08 μb. The t dependence of the differential cross section is consistent with A exp(bt), where b=8.4±0.7 GeV−2. The photon-omega coupling constant, obtained from a normalization of hadron elastic-scattering cross sections to the photoproduction data of this experiment (with use of vector-meson dominance and an additive quark model), is γω24π=5.4±0.4.

4 data tables

THE QUOTED STATISTICAL ERRORS INCLUDE THE UNCERTAINTY IN THE CORRECTION FOR INELASTIC EVENTS. AVERAGE CROSS SECTION IS 1.10 +- 0.08 MUB.

EXPONENTIAL FIT TO DIFFERENTIAL CROSS SECTION.

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PRODUCTION OF PHOTONS ASSOCIATED WITH THE PSI BY 217-GEV/C PI- MESONS

Kirk, T.B.W. ; Raja, R. ; Goodman, M. ; et al.
Phys.Rev.Lett. 42 (1979) 619-622, 1979.
Inspire Record 145303 DOI 10.17182/hepdata.20780

Dimuon production is studied in 217-GeV/c π−-hydrogen and π−-beryllium collisions with a lead-glass array to detect photons associated with the ψ. The ψ−γ mass spectrum shows a 2.6-standard-deviation excess of events above background at ∼3.5 GeV. This excess, if attributed to the decay χ(∼3.5)→ψγ, implies that 0.70±0.28 of the ψ's are produced via radiative decay of one of the χ states.

2 data tables

E*D(SIG)/D(XL) is fitted by (1-X)**POWER.

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Charged-Particle Multiplicities in 100 GeV/c $\bar{p}p$ Interactions

Ansorge, R.E. ; Bust, C.P. ; Carter, J.R. ; et al.
Phys.Lett.B 59 (1975) 299-302, 1975.
Inspire Record 2603 DOI 10.17182/hepdata.27765

Results are presented on the topological cross sections obtained for antiproton-proton interactions from an exposure of the Fermilab 30-inch bubble chamber to a 100 GeV/ c negative beam enriched in p 's. The p p inelastic cross section is found to be σ inel = 34.6 ± 0.4 mb, and the average inelastic charged particle multiplicity to be 〈 n 〉 = 6.74 ± 0.05.

3 data tables

ERRORS ARE STATISTICAL ONLY EXCEPT FOR 2-PRONG CROSS-SECTIONS.

EXPONENTIAL FIT TO ELASTIC T DISTRIBUTION TO CORRECT FOR AN APPARENT LOSS OF EVENTS AT SMALL -T.

MOMENTS OF 100 GEV/C AP P MULTIPLICITY DISTRIBUTION.


Study of pi- Meson Elastic Scattering by Protons at Small Angles

Apokin, V.D. ; Derevshchikov, A.A ; Matulenko, Yu.A. ; et al.
Yad.Fiz. 21 (1975) 1240-1246, 1975.
Inspire Record 103333 DOI 10.17182/hepdata.19099

None

3 data tables

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IM(AMP) VIA OPTICAL THEOREM FROM TOTAL CROSS SECTIONS OF L. M. VASILYEV ET AL., PL 36B, 528 (1971).


Lambda p Interactions Below 24-GeV/c

Mount, R.P. ; Ansorge, R.E. ; Carter, J.R. ; et al.
Phys.Lett.B 58 (1975) 228-232, 1975.
Inspire Record 103555 DOI 10.17182/hepdata.27777

Λp interactions have been studied at momenta up to 24 GeV/ c using a new bubble chamber technique. We find that the Λp elastic cross section has fallen to approximately 6 mb at the highest momentum. Results are presented on Λ p→ Λ p π + π − for the first time above 5 GeV c .

4 data tables

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ESTIMATE.

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Cross Sections and Charged Particle Multiplicities at 102 GeV/c and 405 GeV/c.

Bromberg, C. ; Chaney, D. ; Cohen, Daniel H. ; et al.
Phys.Rev.Lett. 31 (1973) 1563-1566, 1973.
Inspire Record 81962 DOI 10.17182/hepdata.21360

We have measured the total inelastic cross section (σinel) and charged-particle multiplicities obtained in pp collisions at 405 GeV/c. The data are from a preliminary 12 000-picture bubble-chamber exposure. We find σinel=32.8±1.0 mb; the low moments of the multiplicity distribution for negative particles are 〈n−〉=3.50±0.07, D−=2.37±0.05, f2−=2.1±0.2, and f3−=0.1±0.9. We also present updated results at 102 GeV/c.

3 data tables

SUPERCEDES PRELIMINARY RESULTS IN J. W. CHAPMAN ET AL., PRL 29, 1686 (1972).

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FIT TO ELASTIC DIFFERENTIAL CROSS SECTION FOR 0.05 < -T < 0.7 GEV**2.