Bell, W.
SLOPE
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The $\rho^\prime$ (1600) in the Reaction $\gamma p \to \pi^+ \pi^- \pi^0 \pi^0 p$ at Photon Energies of 20-{GeV} to 70-{GeV}

The Omega Photon collaboration Atkinson, M. ; Axon, T.J. ; Barberis, D. ; et al.
Z.Phys.C 26 (1985) 499, 1985.
Inspire Record 202941 DOI 10.17182/hepdata.15774

The reactionγp→π+π−π0π0p (excludingωπ0 production) has been studied for photon energies in the range 20–70 GeV. A peak is seen in the 4π mass spectrum at ∼1.66 GeV with a width of ∼0.3 GeV which is identified with theρ′(1600). Maximum likelihood fits show that the peak is dominantly inρ±π∓π0 withB(ρ′→ρ0π0π0)/B(ρ′→ρ±π∓π0)<0.1. This indicates anI=1ρπ final-state interaction. However, no evidence is found for any resonant ρπ state such as anA1 orπ′.

2 data tables
Table 1

AFTER OMEGA EXCLUSION.

Table 2

ERROR IS DOMINANTLY SYSTEMATIC.


LOW-ENERGY ANTI-PROTON INTERACTION STUDIES AT BROOKHAVEN

Sakitt, M. ; Ashford, V. ; Sainio, M.E. ; et al.
Conf.Proc.C 840709 (1984) 205, 1984.
Inspire Record 209026 DOI 10.17182/hepdata.50261

None

3 data tables
Table 1

TYPICAL QUASIELASTIC ANGULAR DISTRIBUTION FOR NUCLEAR TARGET. OTHER DATA ARE IN ASHFORD ET AL (1985-PHYS REV C).

Table 2

ABSORPTION CROSS SECTIONS.

Table 3

No description provided.


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
Table 1

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

Table 2

No description provided.

Table 3

No description provided.

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A Spin Parity Analysis of the $\omega \pi^0$ Enhancement Photoproduced in the Energy Range 20-{GeV} to 70-{GeV}

The Omega Photon collaboration Atkinson, M. ; Axon, T.J. ; Barberis, D. ; et al.
Nucl.Phys.B 243 (1984) 1-28, 1984.
Inspire Record 195216 DOI 10.17182/hepdata.33872

A study is made of the ωπ 0 system produced near threshold in the reaction γ p→ π + π − π 0 π 0 p. A spin-parity analysis shows that the ωπ 0 enhancement is consistent with predominant 1 + B(1235) production, with ∼20% J P = 1 − background.

2 data tables
Table 1

MEAN BEAM ENERGY IS 39 GEV.

Table 2

ESTIMATE OF B(1235) PRODUCTION CROSS SECTION ASSUMING 1+ CROSS SECTION OF 0.63 +- 0.20 MUB AND THAT 20 PCT OF THIS IS DUE TO BACKGROUND S-WAVE CONTRIBUTIONS.


Observation of a Peak at 1.28-{GeV} in the $\eta \pi \pi$ System in the Reaction $\gamma p \to \eta \pi^+ \pi^- p$

The Omega Photon collaboration Atkinson, M. ; Axon, T.J. ; Barberis, D. ; et al.
Nucl.Phys.B 242 (1984) 269-281, 1984.
Inspire Record 194474 DOI 10.17182/hepdata.33873

A peak is reported in the ηπ + π − system, produced in the reaction γ p→ ηπ + π − p, at a mass of 1.28 ± 0.01 GeV with a width of 0.08 ± 0.02 GeV. Possible spin-parity assignments for the peak are shown to be J π = 1 − , J π = 1 + or J π = 2 + and interpretations of these assignments are discussed.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Photoproduction of $\pi^+ \pi^- \pi^0$ on Hydrogen With Linearly Polarized Photons of Energy 20-{GeV} - 70-{GeV}

The Omega Photon & Bonn-CERN-Glasgow-Lancaster-Manchester-Paris-Rutherford-Sheffield collaborations Atkinson, M. ; Axon, T.J. ; Barberis, D. ; et al.
Nucl.Phys.B 231 (1984) 15-39, 1984.
Inspire Record 191169 DOI 10.17182/hepdata.33892

Results on photoproduction of π + π − π 0 in the photon energy range 20–70 GeV are presented. For the ω meson, the production cross-section is found to be 1010±15 (statistical)±290 (systematic) nb and is constant over the incident photon energy range. Spin-density matrix elements are evaluated for ω meson production. The φ meson is observed with a total photoproduction cross section (corrected for branching ratio to π + π − π 0 ) of 610±35±170 nb. A third resonance, at 1.67 GeV, is seen in the mass spectrum and its interpretation is discussed. The production of a broad π + π − π 0 continuum, mainly via ϱπ, and peaking at 1.2 GeV, contributes with a cross section of about 2.5 ωb. The spin-parity content is analysed by the moments of the π + π − π 0 decay angular distribution in the helicity frame and by maximum likelihood fits to the π + π − π 0 Dalitz plot. It is found that production of J P = 1 − states accounts for less than half of the total mass spectrum above 900 MeV. There is a broad enhancement in the 1 + wave around 1.15 GeV indicating photoproduction of the H(1190) meson.

6 data tables
Table 1

No description provided.

Table 2

EXPONENTIAL FITS TO D(SIG)/DT IN OMEGA MASS REGION.

Table 3

EXPONENTIAL FITS TO D(SIG)/DT OVER FULL ENERGY FOR THREE MASS REGIONS CORRESPONDING TO OMEGA, PHI AND OMEGA*.

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Elastic and total cross-section measurement at the CERN proton-antiproton collider

The UA1 collaboration Arnison, G. ; Astbury, A. ; Aubert, Bernard ; et al.
Phys.Lett.B 128 (1983) 336, 1983.
Inspire Record 190339 DOI 10.17182/hepdata.30668

Proton-antiproton elastic scattering at CM energy 540 GeV has been studied in the t -range 0.04 < − t < 0.45 GeV 2 . The data are well fitted by the form exp ( bt ) with b = 17.1 ± 1.0 GeV −2 for | t | = 0.04 − 0.18 GeV su 2 and b = 13.7 ± 0.2 ± 0.2 GeV −2 for | t | = 0.21−0.45 GeV 2 . A luminosity measurement combined with the optical theorem gives σ tot = 67.6 ± 5.9 ± 2.7 mb and σ e1 / σ tot = 0.209 ± 0.018 ± 0.008.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

ELASTIC RATIO ASSUMES RHO=0.


MEASUREMENT OF n p ELASTIC SCATTERING AT HIGH-ENERGIES AND VERY SMALL MOMENTUM TRANSFERS

The Freiburg-Moscow collaboration Arefev, A. ; Babaev, A. ; Bamberger, A. ; et al.
Nucl.Phys.B 232 (1984) 365, 1984.
Inspire Record 190837 DOI 10.17182/hepdata.33883

The np elastic differential cross section has been measured for incident neutron momenta 100–400 GeV/ c in the | t | range 6 · 10 −6 − 5 · 10 −1 (GeV/ c ) 2 . The np data of this experiment provide a first direct measurement of the hadronic amplitude for | t | < 10 −2 (GeV/ c ) 2 , which is consistent with the extrapolations from higher | t | values. Our data for | t | < 10 −4 (GeV/ c ) 2 are consistent with a rise which can be attributed to Schwinger scattering, caused by the interaction of the neutron magnetic moment with the proton.

10 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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The Reactions $pp \to pp$ $\pi^+ \pi^-, K^+ p \to K^+ p$ $\pi^+ \pi^-$, $\pi^+ p \to \pi^+ p$ $\pi^+ \pi^-$ and $\pi^- p \to \pi^+ \pi^-$ at 147 GeV/c

Brick, D.H. ; Rudnicka, H. ; Shapiro, A.M. ; et al.
Z.Phys.C 19 (1983) 1-9, 1983.
Inspire Record 194363 DOI 10.17182/hepdata.16321

We have studied the reactionspp→ppπ+π-,K+p→K+pπ+π−π, π+p→ π+,pπ+π− and π−p →π+π− at 147 GeV/c using the 30-inch Fermilab hybrid system. All four reactions were detected with the same apparatus and analyzed in the same way. The energy dependence of the channel cross section was found to beAp−0.6+B for thepp reaction andAp−1+B for the other three. About 90% of the cross section at 147 GeV/c can be accounted for by either beam or target diffraction. Some of the remaining cross section may come from double Pomeron exchange reactions which we tried to isolate. We have tested the hypothesis of a factorizable Pomeron and our data indicates a violation of this hypothesis. We show that the 3π mass enhancement in the mass region 1.2–1.4 GeV is diffractively produced in the π± beam reactions. Fourprong, four-constraint and six-prong, four-constraint cross sections are reported.

6 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

CROSS SECTIONS FOR DIFFRACTION DISSOCIATION OF BEAM. FEYNMAN X OF OUTGOING PROTON <-0.96.

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Differential Cross-sections of Proton Compton Scattering at Photon Laboratory Energies Between 1.2-{GeV} and 1.7-{GeV}

Duda, J. ; Hofner, F.W. ; Jung, M. ; et al.
Z.Phys.C 17 (1983) 319, 1983.
Inspire Record 182590 DOI 10.17182/hepdata.50210

Differential cross sections of proton Compton scattering have been measured at the Bonn 2.5 GeV synchrotron. The experiment covers photon laboratory energies between 1.2 GeV and 1.7 GeV and the square of the four-momentum transfer ranges fromt=−0.17 GeV2 to −0.98GeV2 corresponding to c.m. scattering angles between 35° and 80°. The cross sections exhibit a forward peak followed by a monotone fall-off up to the largest measured |t|-values. Fits of the formdσ/dt=A·exp(Bt) to the data points with |t|≦0.5 GeV2 yield forward cross sectionsA, which are consistent with the 0° cross sections calculated from the measured total photon-proton cross section. The average slope isB=5.6±0.14 GeV2.

13 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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