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Bubble Chamber Study of Photoproduction by 2.8-GeV and 4.7-GeV Polarized Photons. 1. Cross-Section Determinations and Production of rho0 and Delta++ in the Reaction gamma p --> p pi+ pi-

Ballam, Joseph ; Chadwick, G.B. ; Gearhart, R. ; et al.
Phys.Rev.D 5 (1972) 545, 1972.
Inspire Record 67165 DOI 10.17182/hepdata.3635

Photoproduction is studied at 2.8 and 4.7 GeV using a linearly polarized monoenergetic photon beam in a hydrogen bubble chamber. We discuss the experimental procedure, the determination of channel cross sections, and the analysis of the channel γp→pπ+π−. A model-independent analysis of the ρ0-decay angular distribution allows us to measure nine independent density-matrix elements. From these we find that the reaction γp→pρ0 proceeds almost completely through natural parity exchange for squared momentum transfers |t|<1 GeV2 and that the ρ production mechanism is consistent with s-channel c.m. helicity conservation for |t|<0.4 GeV2. A cross section for the production of π+π− pairs in the s-channel c.m. helicity-conserving p-wave state is determined. The ρ mass shape is studied as a function of momentum transfer and is found to be inconsistent with a t-independent Ross-Stodolsky factor. Using a t-dependent parametrization of the ρ0 mass shape we derive a phenomenological ρ0 cross section. We compare our phenomenological ρ0 cross section with other experiments and find good agreement for 0.05<|t|<1 GeV2. We discuss the discrepancies in the various determinations of the forward differential cross section. We study models for ρ0 photoproduction and find that the Söding model best describes the data. Using the Söding model we determine a ρ0 cross section. We determine cross sections and nine density-matrix elements for γp→Δ++π−. The parity asymmetry for Δ++ production is incompatible with simple one-pion exchange. We compare Δ++ production with models.

20 data tables
Table 1

FROM QUOTED TOPOLOGICAL CROSS SECTIONS. 1.44 GEV CROSS SECTION PUBLISHED PREVIOUSLY.

Table 2

No description provided.

Table 3

NO TMIN CORRECTION HAS BEEN MADE.

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MEASUREMENT OF THE REAL TO IMAGINARY RATIO OF THE ANTI-P P FORWARD SCATTERING AMPLITUDES

Ashford, V. ; Sainio, M.E. ; Sakitt, M. ; et al.
Phys.Rev.Lett. 54 (1985) 518-521, 1985.
Inspire Record 216074 DOI 10.17182/hepdata.20329

We have measured the ratio of the real to the imaginary parts of the p¯p forward-scattering amplitude in the incident-momentum range 360 to 650 MeV/c. These results are in good agreement with predictions of the Paris nucleon-antinucleon potential model which include spin-flip effects.

3 data tables
Table 2

RESULTS OF FITS TO THE FORWARD-SCATTERING DIFFERENTIAL CROSS SECTIONS ASSUMING THE RATIO OF THE SPIN-FLIP TO NON-SPIN-FLIP PARTS OF THE FORWARD AMPLITUDE IS ZERO.

Table 3

RESULTS OF FITS TO THE FORWARD-SCATTERING DIFFERENTIAL CROSS SECTIONS ASSUMING THE RATIO OF THE SPIN-FLIP TO NON-SPIN-FLIP PARTS OF THE FORWARD AMPLITUDE IS PARAMATERISED AS 0.3698-0.1384*PLAB(IN GEV).


Photoproduction of pi0 omega off protons for E(gamma) < 3-GeV.

The CB-ELSA collaboration Junkersfeld, J. ; Anisovich, A.V. ; Anton, G. ; et al.
Eur.Phys.J.A 31 (2007) 365-372, 2007.
Inspire Record 748502 DOI 10.17182/hepdata.43511

Differential and total cross-sections for photoproduction of gamma proton to proton pi0 omega and gamma proton to Delta+ omega were determined from measurements of the CB-ELSA experiment, performed at the electron accelerator ELSA in Bonn. The measurements covered the photon energy range from the production threshold up to 3GeV.

18 data tables
Table 1

Differential cross section as a function of the OMEGA angle.

Table 2

Differential cross section as a function of the OMEGA angle.

Table 3

Differential cross section as a function of the PI0 angle.

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Measurement of the slope of the pi0 electromagnetic form-factor

Farzanpay, F. ; Gumplinger, P. ; Stetz, A. ; et al.
Phys.Lett.B 278 (1992) 413-418, 1992.
Inspire Record 338523 DOI 10.17182/hepdata.29240

We have measured the slope parameter of the π 0 electromagnetic form factor by measuring the partial branching ratio of the Dalitz decay π 0 → γe + e − into high-invariant-mass electron-positron pairs. We obtain a value a =0.026 with a total (statistical and systematic) error of ±0.054, in agreement with vector dominance and quark loop calculations.

1 data table
Table 1

The PI0 form factor is parameterized as F(M(ee)**2) = 1 + SLOPE*(M(ee)/M(pi))**2. Two metod are used (see text for detail).


Determination of anti-proton neutron amplitude from elastic anti-p deuteron scattering at 600-MeV/c

Mahalanabis, J. ;
Z.Phys.A 342 (1992) 101-105, 1992.
Inspire Record 343348 DOI 10.17182/hepdata.16576

The elementary ¯p-neutron amplitude has been obtained from Glauber's model analysis of ¯p-d elastic scattering data at 600 MeV/c, taking into account theD-state component of the deuteron. The results are compared with the ¯p-nucleus analysis and the ¯NN potential model predictions.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Anti-D0 meson production in interactions of neutrons with hydrogen, carbon, and aluminum nuclei at 37.5-GeV to 70-GeV

The BIS-2 collaboration Aleev, A.N. ; Arefev, V.A. ; Balandin, V.P. ; et al.
Phys.Atom.Nucl. 56 (1993) 1235-1240, 1993.
Inspire Record 364824 DOI 10.17182/hepdata.17203

None

6 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Real to Imaginary Ratio of the $\bar{p} p$ Forward Elastic Scattering Amplitude at 550-{MeV}/$c$, 757-{MeV}/$c$ and 1077-{MeV}/$c$

Schiavon, P. ; Birsa, R. ; Bos, K. ; et al.
Nucl.Phys.A 505 (1989) 595-609, 1989.
Inspire Record 277295 DOI 10.17182/hepdata.36894

The ratio of the real to the imaginary part of the pp forward elastic-scattering amplitude ϱ has been measured at 550, 757, and 1077 MeV/ c at LEAR, using the Coulomb-nuclear interference method. The results obtained for ρ and b , the nuclear slope, are ϱ = 0.084 ± 0.051 and b = 20.9 ± 2.1 (GeV/ c ) −2 at 550 MeV/ c , ϱ = 0.102 ± 0.043 and b = 18.0 ± 0.5 (GeV/ c ) −2 = at 757 MeV/ c , and ϱ = 0.059 ± 0.035 and b = 15.2 ± 0.3 (GeV/ c ) −2 at 1077 MeV/ c .

4 data tables
Table 1

Error on SLOPE is statistical only.

Table 2

Measured differential cross sections corrected for small-angle trigger efficiency and absorption losses. Statistical errors only.

Table 3

Measured differential cross sections corrected for small-angle trigger efficiency and absorption losses. Statistical errors only.

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Measurement of $d \sigma / d \Omega$ and A(on) in $\bar{p} p$ Elastic Scattering Between 497-{MeV}/$c$ and 1550-{MeV}/$c$

Kunne, R.A. ; Beard, C.I. ; Birsa, R. ; et al.
Nucl.Phys.B 323 (1989) 1-36, 1989.
Inspire Record 267175 DOI 10.17182/hepdata.48676

Measurements have been made of the differential cross section and asymmetry A on for p p elastic scattering at 15 incident momenta between 497 MeV/ c and 1550 MeV/ c . The angular range where both particles have enough energy to traverse target and setup has been covered. The results are compared with predictions of various N N potential models. None of these models fully explains the present results, although the general trend of the data is predicted correctly.

16 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Measurement of Anti-proton - Proton Small Angle Elastic Scattering at Low Momentum

Linssen, L. ; Beard, C.I. ; Birsa, R. ; et al.
Nucl.Phys.A 469 (1987) 726, 1987.
Inspire Record 245092 DOI 10.17182/hepdata.37014

Two high statistics measurements of antiproton-proton small-angle elastic scattering, at p = 233 MeV/ c and p = 272 MeV/ c , are presented. The measurements were carried out at the LEAR facility at CERN. By the Coulomb-nuclear interference method, values are obtained for the real-to-imaginary ratio ρ of the p̄p forward nuclear scattering amplitude and for its exponential slope b : ρ = + 0.041 ± 0.026 and b = 71.5 ± 4.5 (GeV/ c ) −2 at 233 MeV/ c and ρ = −0.014 ± 0.027 and b = 47.7 ± 2.7 (GeV/ c ) −2 at 272 MeV/ c . The method to derive these values is discussed in detail and so are the uncertainties contributing to their systematic error. The results are compared with predictions from forward dispersion relation calculations and with predictions from p̄p potential models.

3 data tables
Table 1

The corrected cross section is the measured divided by the average folding correction given in the paper.

Table 2

The corrected cross section is the measured divided by the average folding Correction given in the paper.

Table 3

Fits to data use the value of total cross sections of 263 & 296 mb for 272 & 233 Mev respectively derived from the authors total cross sections measurement. ETA is the spin dependence parameter.


Real to Imaginary Ratio of the $\bar{p} p$ Forward Elastic Scattering Amplitude in the Momentum Range Between 180-{MeV}/$c$ and 590-{MeV}/$c$

Bruckner, W. ; Dobbeling, H. ; Guttner, F. ; et al.
Phys.Lett.B 158 (1985) 180-185, 1985.
Inspire Record 213992 DOI 10.17182/hepdata.30392

The real-to-imaginary ratio of the p p forward elastic scattering amplitude has been measured at the LEAR facility of CERN by the Coulomb-nuclear interference method at seven beam momenta between 181 and 590 MeV/ c . The ratio is positive at 590 MeV/ c , becomes negative below 500 MeV/ c , reaches a minimum at 260 MeV/ c and then crosses zero again at about 230 MeV/ c .

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.