High statistics measurement of the cross sections of gamma gamma --> pi+ pi- production.

The Belle collaboration Mori, T. ; Uehara, S. ; Watanabe, Y. ; et al.
J.Phys.Soc.Jap. 76 (2007) 074102, 2007.
Inspire Record 749358 DOI 10.17182/hepdata.51842

We report on a high statistics measurement of the total and differential cross sections of the process gamma gamma -> pi^+ pi^- in the pi^+ pi^- invariant mass range 0.8 GeV/c^2 < W < 1.5 GeV/c^2 with 85.9 fb^{-1} of data collected at sqrt{s}=10.58 GeV and 10.52 GeV with the Belle detector. A clear signal of the f_0(980) resonance is observed in addition to the f_2(1270) resonance. An improved 90% confidence level upper limit Br.(eta'(958) -> pi^+ pi^-) < 2.9 x 10^{-3} is obtained for P- and CP-violating decay of the eta'(958) meson using the most conservative assumption about the interference with the background.

1 data table match query

Total cross section.


High-statistics measurement of neutral pion-pair production in two-photon collisions

The Belle collaboration Uehara, S. ; Watanabe, Y. ; Adachi, I. ; et al.
Phys.Rev.D 78 (2008) 052004, 2008.
Inspire Record 786406 DOI 10.17182/hepdata.50151

We report a high-statistics measurement of differential cross sections for the process gamma gamma -> pi^0 pi^0 in the kinematic range 0.6 GeV <= W <= 4.0 GeV and |cos theta*| <= 0.8, where W and theta* are the energy and pion scattering angle, respectively, in the gamma gamma center-of-mass system. Differential cross sections are fitted to obtain information on S, D_0, D_2, G_0 and G_2 waves. The G waves are important above W ~= 1.6 GeV. For W <= 1.6 GeV the D_2 wave is dominated by the f_2(1270) resonance while the S wave requires at least one additional resonance besides the f_0(980), which may be the f_0(1370) or f_0(1500). The differential cross sections are fitted with a simple parameterization to determine the parameters (the mass, total width and Gamma_{gamma gamma}B(f_0 -> pi^0 pi^0)) of this scalar meson as well as the f_0(980). The helicity 0 fraction of the f_2(1270) meson, taking into account interference for the first time, is also obtained.

2 data tables match query

Differential cross section for W = 1.33, 1.35 and 1.37 GeV.

Total cross section for the cos(theta*) ranges 0.0 to 0.6 and 0.0 to 0.8.


Differential Cross-Sections for the pi0 Photoproduction at Theta (CM) = 90-Degrees and K (Lab) = 380-MeV-820-MeV

Jung, M. ; Kattein, J. ; Leu, P. ; et al.
BONN-HE-76-15, 1976.
Inspire Record 111677 DOI 10.17182/hepdata.50235

None

1 data table match query

No description provided.


Forward Photoproduction of Neutral Pions on Polarized Protons in the Third Resonance Region

Herr, H. ; Husmann, D. ; Jansen, W. ; et al.
Nucl.Phys.B 125 (1977) 157-161, 1977.
Inspire Record 118996 DOI 10.17182/hepdata.50398

Angular distributions of the target symmetry for the reaction γ + p → π 0 + p have been measured at the Bonn 2.5 GeV Electron Synchrotron at pion c.m. angles between 13° and 63° and photon energies of 1.0 and 1.1 GeV. The π 0 mesons were detected by their two decay photons with total absorption lead-glass Čerenkov counters. Butanol was used as target material in a continuous flow 3 He cryostat operating at 0.5 K and 25 kG. The π 0 counting rate from free protons in the butanol target was derived from the measurements of the differential cross section on hydrogen. The data are compared with data of other laboratories and the results of two recent partial-wave analyses.

1 data table match query

No description provided.


NEUTRAL PION PHOTOPRODUCTION ON THE DEUTERON

Imanishi, A. ; Ishii, T. ; Kato, S. ; et al.
Phys.Rev.Lett. 54 (1985) 2497-2500, 1985.
Inspire Record 220232 DOI 10.17182/hepdata.20385

Large-angle cross sections for γd→π0d are systematically measured in the photon energy range between 500 and 1000 MeV. A good fit is obtained by use of a Glauber-model calculation which includes the dibaryon resonances F33(2.26) and G41(2.51), but the fit has an unusual nature in the role of resonance and nonresonance contributions.

1 data table match query

Liquid hydrogen target for final calibration.


Mass identified particle production in proton anti-proton collisions at s**(1/2) = 300-GeV, 540-GeV, 1000-GeV, and 1800-GeV

The E735 collaboration Alexopoulos, T. ; Allen, C. ; Anderson, E.W. ; et al.
Phys.Rev.D 48 (1993) 984-997, 1993.
Inspire Record 363171 DOI 10.17182/hepdata.22669

The yields and average transverse momenta of pions, kaons, and antiprotons produced at the Fermilab p¯p collider at s=300, 540, 1000, and 1800 GeV are presented and compared with data from the energies reached at the CERN collider. We also present data on the dependence of average transverse momentum 〈pt〉 and particle ratios as a function of charged particle density dNcdη; data for particle densities as high as six times the average value, corresponding to a Bjorken energy density 6 GeV/fm3, are reported. These data are relevant to the search for quark-gluon phase of QCD.

2 data tables match query

No description provided.

No description provided.


Charged-pi photoproduction at 180 degress in the energy range between 300 and 1200 mev

Fujii, T. ; Okuno, H. ; Orito, S. ; et al.
Phys.Rev.Lett. 26 (1971) 1672-1675, 1971.
Inspire Record 68981 DOI 10.17182/hepdata.21616

The differential cross sections at 180° for the reactions γ+p→π++n and γ+n→π−+p were measured using a magnetic spectrometer to detect π± mesons. In order to reduce the spread of energy resolution due to the nucleon motion inside the deuteron, a photon difference method was employed with a 50-MeV step for the reaction γ+n→π−+p. The data show structures at the second- and the third-resonance regions for both reactions. A simple phenomenological analysis was made for fitting the data, and the results are compared with those of previous analyses.

2 data tables match query

No description provided.

No description provided.


Proton Compton Scattering Measurement From 450 to 1350 MeV Near 90-degrees in the Center-of-Mass System

Rust, D.R. ; Eisenhandler, E. ; Mostek, P.J. ; et al.
Phys.Rev.Lett. 15 (1965) 938-941, 1965.
Inspire Record 944922 DOI 10.17182/hepdata.21794

None

1 data table match query

No description provided.


Proton form factors from elastic electron-proton scattering

Janssens, T. ; Hofstadter, R. ; Hughes, E.B. ; et al.
Phys.Rev. 142 (1966) 922-931, 1966.
Inspire Record 49127 DOI 10.17182/hepdata.26698

Absolute measurements of the elastic electron-proton cross section have been made with a precision of about 4% for values of the square of the four-momentum transfer, q2, in the range 6.0 to 30.0 F−2 and for electron scattering angles in the range 45° to 145°. To within the experimental errors, it is found that the charge and magnetic form factors of the proton have a common dependence on q2 when normalized to unity at q2=0, and that an accurate representation of the behavior of the form factor and that of the cross sections themselves can be given in terms of a three-pole approximation to the dispersion theory of nucleon form factors.

10 data tables match query

Axis error includes +- 2./2. contribution (RANDOM ERROR).

Axis error includes +- 2./2. contribution (RANDOM ERROR).

Axis error includes +- 2./2. contribution (RANDOM ERROR).

More…

pi+ Photoproduction from Hydrogen at Lab Angles from 34-degrees to 155-degrees and Lab Photon Energies from 500 to 1350 MeV

Thiessen, Henry A. ;
Phys.Rev. 155 (1967) 1488-1496, 1967.
Inspire Record 52277 DOI 10.17182/hepdata.26588

The differential cross section for the reaction γ+p→π++n was measured using the Caltech 1.5-GeV electron synchrotron. The positive pions were detected and momentum analyzed in a multichannel magnetic spectrometer and the data were recorded in the memory of a pulse-height analyzer. The energy resolution was improved over previous experiments and an attempt was made to minimize systematic errors. The data are presented in the form of energy distributions at 12 lab angles from 34° to 155°, and the range of lab proton energies extended from 500 to 1350 MeV. Data were not taken at all energies for each angle, since the maximum useful momentum of the spectrometer, 600 MeVc, restricted the maximum energy for lab angles less than or equal to 74°.

1 data table match query

No description provided.


Photoproduction of pi0 Mesons from Hydrogen near Zero Degrees

Highland, V.L. ; DeWire, J.W. ;
Phys.Rev. 132 (1963) 1293-1297, 1963.
Inspire Record 944974 DOI 10.17182/hepdata.26730

We report measurements of the differential cross section for photoproduction of π0 mesons from hydrogen, with the pion emerging near 0 deg, in the photon energy range 290 to 700 MeV. The results show no unusual behavior of the cross section in the forward direction. They are consistent with the angular distribution characteristic of a magnetic-dipole transition to a P32 state. The results agree reasonably well with theoretical predictions of Gourdin and Salin, but disagree with a prediction of DeTollis and Verganelakis. Least-squares fits in powers of cosθ have been made to the available angular distributions.

1 data table match query

No description provided.


Measurements of the pi- p --> pi0 n Forward Scattering Cross-Section in the Energy Region 400-MeV-600-MeV

Kravtsov, A.V. ; Kuzmin, L.A. ; Nemozhenko, O.N. ; et al.
Nucl.Phys.B 140 (1978) 279-284, 1978.
Inspire Record 135966 DOI 10.17182/hepdata.34984

The forward charge-exchange differential cross section has been measured using two Čerenkov spectrometers at five energies of incident pions. The resulting cross-section values are 4.02 ± 0.22, 3.61 ± 0.13, 4.19 ± 0.13, 3.91 ± 0.12, 3.02 ± 0.14 mb/sr at incident pion energies 400, 450, 500, 550 and 600 MeV, respectively. These values are in a good agreement with dispersion-relation predictions.

1 data table match query

No description provided.


Differential Cross-Sections of the Proton Compton Scattering in the Energy Between 450-MeV and 950-MeV

Toshioka, K. ; Chiba, M. ; Kato, S. ; et al.
Nucl.Phys.B 141 (1978) 364-378, 1978.
Inspire Record 120614 DOI 10.17182/hepdata.34955

The differential cross sections of the proton Compton scattering around the second resonance have been measured at a c.m. angle of 90° for incident photon energies between 450 MeV and 950 MeV in steps of 50 MeV, and at an angle of 60° for energies between 600 MeV and 800 MeV. The results show that the peak of the 2nd resonance agrees with that of the pion photoproduction process. We also calculated the proton Compton scattering based on unitarity and fixed- t dispersion relations. The calculation describes well the data of the cross section and the recoil proton polarization.

1 data table match query

No description provided.


Rho Production by Virtual Photons

Joos, P. ; Ladage, A. ; Meyer, H. ; et al.
Nucl.Phys.B 113 (1976) 53-92, 1976.
Inspire Record 108749 DOI 10.17182/hepdata.35708

The reaction γ V p → p π + π − was studied in the W , Q 2 region 1.3–2.8 GeV, 0.3–1.4 GeV 2 using the streamer chamber at DESY. A detailed analysis of rho production via γ V p→ ϱ 0 p is presented. Near threshold rho production has peripheral and non-peripheral contributions of comparable magnitude. At higher energies ( W > 2 GeV) the peripheral component is dominant. The Q 2 dependence of σ ( γ V p→ ϱ 0 p) follows that of the rho propagator as predicted by VDM. The slope of d σ /d t at 〈 Q 2 〉 = 0.4 and 0.8 GeV 2 is within errors equal to its value at Q 2 = 0. The overall shape of the ϱ 0 is t dependent as in photoproduction, but is independent of Q 2 . The decay angular distribution shows that longitudinal rhos dominate in the threshold region. At higher energies transverse rhos are dominant. Rho production by transverse photons proceeds almost exclusively by natural parity exchange, σ T N ⩾ (0.83 ± 0.06) σ T for 2.2 < W < 2.8 GeV. The s -channel helicity-flip amplitudes are small compared to non-flip amplitudes. The ratio R = σ L / σ T was determined assuming s -channel helicity conservation. We find R = ξ 2 Q 2 / M ϱ 2 with ξ 2 ≈ 0.4 for 〈 W 〉 = 2.45 GeV. Interference between rho production amplitudes from longitudinal and transverse photons is observed. With increasing energy the phase between the two amplitudes decreases. The observed features of rho electroproduction are consistent with a dominantly diffractive production mechanism for W > 2 GeV.

1 data table match query

DIPION CHANNEL CROSS SECTION.


Compton scattering by the proton through Theta(CMS) = 75-degrees and 90-degrees in the Delta resonance region

Hünger, A ; Peise, J ; Robbiano, A ; et al.
Nucl.Phys.A 620 (1997) 385-416, 1997.
Inspire Record 458618 DOI 10.17182/hepdata.36349

Differential cross sections for Compton scattering by the proton have been measured in the energy interval between 200 and 500 MeV at scattering angles of θ cms = 75° and θ cms = 90° using the CATS, the CATS/TRAJAN, and the COPP setups with the Glasgow Tagger at MAMI (Mainz). The data are compared with predictions from dispersion theory using photo-meson amplitudes from the recent VPI solution SM95. The experiment and the theoretical procedure are described in detail. It is found that the experiment and predictions are in agreement as far as the energy dependence of the differential cross sections in the Δ-range is concerned. However, there is evidence that a scaling down of the resonance part of the M 1+ 3 2 photo-meson amplitude by (2.8 ± 0.9)% is required in comparison with the VPI analysis. The deduced value of the M 1+ 3 2 - photoproduction amplitude at the resonance energy of 320 MeV is: |M 1+ 3 2 | = (39.6 ± 0.4) × 10 −3 m π + −1 .

1 data table match query

No description provided.


OBSERVATION OF INVERSE ELECTROPRODUCTION OF PIONS ON C-12 NUCLEUS AT 164-MeV PION ENERGY AND DETERMINATION OF F1(v) NUCLEON FORM-FACTOR

Alekseev, G.D. ; Blokhintseva, T.D. ; Karpukhin, V.V. ; et al.
Sov.J.Nucl.Phys. 46 (1987) 801, 1987.
Inspire Record 247868 DOI 10.17182/hepdata.38865

None

1 data table match query

No description provided.


PROTON COMPTON EFFECT

Nagashima, Yorikiyo ;
INSJ-81, 1964.
Inspire Record 1101996 DOI 10.17182/hepdata.69229

None

2 data tables match query

No description provided.

No description provided.


Forward Electroproduction of Single Charged Pions in the Resonance Region Using a Deuterium Target

Morris, J.V. ; Darvill, D.C. ; Davenport, M. ; et al.
Phys.Lett.B 73 (1978) 495-499, 1978.
Inspire Record 122614 DOI 10.17182/hepdata.27480

The rates for forward electroproduction of single charged pions from deutrium have been measured in the resonance region, at a virtual photon mass squared ≈−0.5( GeV/ c 2 ) 2 . Results are presented in the form of a π − to π + cross-section ratio.

1 data table match query

No description provided.


Structure of the Proton

Chambers, E.E. ; Hofstadter, R. ;
Phys.Rev. 103 (1956) 1454-1463, 1956.
Inspire Record 945003 DOI 10.17182/hepdata.26939

The structure and size of the proton have been studied by means of high-energy electron scattering. The elastic scattering of electrons from protons in polyethylene has been investigated at the following energies in the laboratory system: 200, 300, 400, 500, and 550 Mev. The range of laboratory angles examined has been 30° to 135°. At the largest angles and the highest energy, the cross section for scattering shows a deviation below that expected from a point proton by a factor of about nine. The magnitude and variation with angle of the deviations determine a structure factor for the proton, and thereby determine the size and shape of the charge and magnetic-moment distributions within the proton. An interpretation, consistent at all energies and angles and agreeing with earlier results from this laboratory, fixes the rms radius at (0.77±0.10) ×10−13 cm for each of the charge and moment distributions. The shape of the density function is not far from a Gaussian with rms radius 0.70×10−13 cm or an exponential with rms radius 0.80×10−13 cm. An equivalent interpretation of the experiments would ascribe the apparent size to a breakdown of the Coulomb law and the conventional theory of electromagnetism.

1 data table match query

In the experiment just relative cross sections were measured. The absolute values were ascribed at each energy after multiplying experimental data by a co nstant factor to obtain the best fit with theory assuming the diffuse proton model with charge and magnetic moment rms radii 0.08 fm.. The values in the table are extracted from the graphs (see figs. 6 - 9) byZOV.


Photoproduction of Neutral Pions at Forward Angles

Berkelman, Karl ; Waggoner, James A. ;
Phys.Rev. 117 (1960) 1364-1375, 1960.
Inspire Record 46817 DOI 10.17182/hepdata.26899

The bremsstrahlung beam of the Cornell Bev electron synchrotron has been used to study the reaction γ+p→π0+p over the photon energy range 250 Mev to 1 Bev, and for center-of-mass pion angles between 20° and 70°. The recoil protons, of energies between 10 and 60 Mev, were identified and their energies determined using a range telescope of eight thin plastic scintillators enclosed in a vacuum chamber with the thin liquid hydrogen target. Correlated pulse-height information was obtained by photographing an oscilloscope display and was used to sort out the protons from mesons and electrons. Corrections were made for the background of photoprotons from the Mylar target cup, the energy loss of the protons in the liquid hydrogen, absorption and scattering in the counter telescope, and the variation of beam intensity profile with energy. Compared with previous experiments and extrapolations the results show a somewhat smaller forward differential cross section above 400 Mev. The angular distributions obtained from a least-squares fit to all existing data indicate a d32 assignment for the 760-Mev resonance level. Other implications of the data are also discussed.

1 data table match query

No description provided.


High-Energy Photoproduction of pi0 Mesons from Hydrogen

DeWire, J.W. ; Jackson, H.E. ; Littauer, Raphael ;
Phys.Rev. 110 (1958) 1208-1209, 1958.
Inspire Record 944997 DOI 10.17182/hepdata.26907

None

1 data table match query

No description provided.


Photoproduction of Neutral Pions at Energies 500 to 940 Mev

Vette, J.I. ;
Phys.Rev. 111 (1958) 622-631, 1958.
Inspire Record 944995 DOI 10.17182/hepdata.26859

The process γ+p→π0+p has been studied by detecting recoil protons from a liquid hydrogen target which was bombarded by the bremsstrahlung beam of the California Institute of Technology electron synchrotron. The angle and momentum of the recoil protons were measured by a magnetic spectrometer-three scintillation counter coincidence system. The process has been studied between photon laboratory energies of 490 and 940 Mev and between pion center-of-mass angles of 31.5° and 147°. Protons which arose from meson pair production were significant at forward laboratory angles. A correction for this contamination is discussed. The results of these measurements show two interesting features. One is that the total cross section, which falls very rapidly above the 32−32 resonance energy near 320 Mev, reaches a minimum at about 600 Mev, and then increases to a broad maximum near 800 or 900 Mev. The other striking feature of the data is that the shape of the angular distribution seems to change rather suddenly near 900 Mev.

1 data table match query

No description provided.


Photoproduction of pi+ Mesons from Hydrogen in the Region 350-900 Mev

Heinberg, M. ; McClelland, W.M. ; Turkot, F. ; et al.
Phys.Rev. 110 (1958) 1211-1212, 1958.
Inspire Record 46812 DOI 10.17182/hepdata.26860

None

1 data table match query

No description provided.


FORWARD ELECTROPRODUCTION OF CHARGED PIONS FROM DEUTERONS AT Q**2 = 1.0-GeV/c**2

Morris, J.V. ; Darvill, D.C. ; Davenport, M. ; et al.
Phys.Lett.B 86 (1979) 211-214, 1979.
Inspire Record 140702 DOI 10.17182/hepdata.27310

The ratio of π - to π + electroproduction cross sections from deuterium has been measured in the resonance region, at a four-momentum transfer squared close to −1.0 (GeV/ c ) 2 . Results in the forward direction are presented and a comparison is made with predictions based on SU(6) W and the Melosh transformation.

1 data table match query

No description provided.


Inclusive K0(s) Production in e+ e- Annihilation at Energies of 3.6-GeV to 5.0-GeV

The PLUTO collaboration Burmester, J. ; Criegee, L. ; Dehne, H.C. ; et al.
Phys.Lett.B 67 (1977) 367-370, 1977.
Inspire Record 118873 DOI 10.17182/hepdata.27568

We have measured the production cross section for K s 0 in e + e − annihilation from 3.6 to 5.0 GeV center of mass energy. A substantial increase of the K s 0 yield is observed around 4 GeV in qualitative agreement with the charm hypothesis.

1 data table match query

No description provided.