HEPData Search

Showing 10 of 44 results

Scattering of positrons and electrons from protons

Bartel, W. ; Dudelzak, B. ; Krehbiel, H. ; et al.

Phys.Lett.B 25 (1967) 242-245, 1967.

Inspire Record 1389651 DOI 10.17182/hepdata.29449

The ration R = σ(e + = p)/σ(e − + p) of the elastic scattering cross section of positrons and electrons on protons was measured at momentum transfers of 11.66 fm −2 and 35.1 fm −2 . The results are consistent with R = 1.

1 data table

Table 1

No description provided.

The Charge Form Factor of the Proton at a Momentum Transfer of 75 F$^-^2$

Bartel, W. ; Dudelzak, B. ; Krehbiel, H. ; et al.

Phys.Lett.B 25 (1967) 236-237, 1967.

Inspire Record 1333753 DOI 10.17182/hepdata.29448

The proton form factors GE(q2) and GM(q2) are determined at q2 = 75fm−2.

2 data tables

Table 1

No description provided.

Table 2

No description provided.

Elastic Electron-Proton Scattering at Momentum Transfers up to 110 Fermi$^−^2$

Behrend, H.J. ; Brasse, F.W. ; Engler, J. ; et al.

Nuovo Cim.A 48 (1967) 140-164, 1967.

Inspire Record 1185336 DOI 10.17182/hepdata.1060

Using the internal beam of DESY elastic electron-proton cross-sections were measured at various angles between 32° and 130°, and with momentum transfers ofq 2=39, 60, 80 and 110 fm−2. Two single-quadrupole spectrometers, movable around a common liquid-hydrogen target, were used for analysing the momentum of the scattered electrons. Čerenkov and shower counters discriminated against pion and low-energy background. As a cross-section reference, recoil protons from elastic scattering atq 2=10 fm−2 were used, with a quantameter serving as an intermediate monitor. The data are consistent with the Rosenbluth formula, giving real form factorsG E andG M . Both continue to decrease with increasing momentum transfer, but somewhat faster than indicated by measurements performed so far.

9 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

Measurements of the electric and magnetic form-factors of the proton from Q2 = 1.75-GeV/c2 to 8.83-GeV/c**2

Andivahis, L. ; Bosted, Peter E. ; Lung, A. ; et al.

Phys.Rev.D 50 (1994) 5491-5517, 1994.

Inspire Record 372566 DOI 10.17182/hepdata.22354

The proton elastic form factors GEp(Q2) and GMp(Q2) have been extracted for Q2=1.75 to 8.83 (GeV/c)2 via a Rosenbluth separation to ep elastic cross section measurements in the angular range 13°≤θ≤90°. The Q2 range covered more than doubles that of the existing data. For Q2<4 (GeV/c)2, where the data overlap with previous measurements, the total uncertainties have been reduced to < 14% in GEp and < 1.5% in GMp. Results for GEp(Q2) are consistent with the dipole fit GD(Q2)=(1+Q2/0.71)−2, while those for GMp(Q2)/μpGD(Q2) decrease smoothly from 1.05 to 0.92. Deviations from form factor scaling are observed up to 20%. The ratio Q2F2/F1 is observed to approach a constant value for Q2>3 (GeV/c)2. Comparisons are made to vector meson dominance, dimensional scaling, QCD sum rule, diquark, and constituent quark models, none of which fully characterize all the new data.

8 data tables

Table 1

Axis error includes +- 1.6/1.6 contribution (Point-to-point systematic error. The quadrature sum of the point-to-point uncertainties in all quantities which defined the cross section).

Table 2

Axis error includes +- 1.6/1.6 contribution (Point-to-point systematic error. The quadrature sum of the point-to-point uncertainties in all quantities which defined the cross section).

Table 3

Axis error includes +- 1.6/1.6 contribution (Point-to-point systematic error. The quadrature sum of the point-to-point uncertainties in all quantities which defined the cross section).

More…

Measurements of elastic electron - proton scattering at large momentum transfer

Sill, A.F. ; Arnold, R.G. ; Bosted, Peter E. ; et al.

Phys.Rev.D 48 (1993) 29-55, 1993.

Inspire Record 341324 DOI 10.17182/hepdata.22584

Measurements of the forward-angle differential cross section for elastic electron-proton scattering were made in the range of momentum transfer from Q2=2.9 to 31.3 (GeV/c)2 using an electron beam at the Stanford Linear Accelerator Center. The data span six orders of magnitude in cross section. Combinded statistical and systematic uncertainties in the cross section measurements ranged from 3.6% at low Q2 to 19% at high Q2. These data have been used to extract the proton magnetic form factor GMp(Q2) and Dirac form factor F1p(Q2) by using form factor scaling. The logarithmic falloff of Q4F1p expected from leading twist predictions of perturbative quantum chromodynamics is consistent with the new data at high Q2. Some nonperturbative and hybrid calculations also agree with our results.

2 data tables

Table 1

No description provided.

Table 2

Formfactor scaling assumes (Ge=Gm/mu).

Measurements of the Deuteron and Proton Magnetic Form-factors at Large Momentum Transfers

Bosted, Peter E. ; Katramatou, A.T. ; Arnold, R.G. ; et al.

Phys.Rev.C 42 (1990) 38-64, 1990.

Inspire Record 283632 DOI 10.17182/hepdata.26165

Measurements of the deuteron elastic magnetic structure function B(Q2) are reported at squared four-momentum transfer values 1.20≤Q2≤2.77 (GeV/c)2. Also reported are values for the proton magnetic form factor GMp(Q2) at 11 Q2 values between 0.49 and 1.75 (GeV/c)2. The data were obtained using an electron beam of 0.5 to 1.3 GeV. Electrons backscattered near 180° were detected in coincidence with deuterons or protons recoiling near 0° in a large solid-angle double-arm spectrometer system. The data for B(Q2) are found to decrease rapidly from Q2=1.2 to 2 (GeV/c)2, and then rise to a secondary maximum around Q2=2.5 (GeV/c)2. Reasonable agreement is found with several different models, including those in the relativistic impulse approximation, nonrelativistic calculations that include meson-exchange currents, isobar configurations, and six-quark configurations, and one calculation based on the Skyrme model. All calculations are very sensitive to the choice of deuteron wave function and nucleon form factor parametrization. The data for GMp(Q2) are in good agreement with the empirical dipole fit.

2 data tables

Table 1

The measured cross section have been devided by those obtained using the dipole form for the proton form factors: G_E=1/(1+Q2/0.71)**2, G_E(Q2)=G_M(Q2)/mu,where Q2 in GeV2, mu=2.79.

Table 2

Axis error includes +- 0.0/0.0 contribution (?////Errors given are the statistical errors and systematic uncertainties add ed in quadreture).

Measurement of Elastic electron Scattering from the Proton at High Momentum Transfer

Arnold, R.G. ; Bosted, Peter E. ; Chang, C.C. ; et al.

Phys.Rev.Lett. 57 (1986) 174, 1986.

Inspire Record 228320 DOI 10.17182/hepdata.3133

We have performed absolute measurements of the differential cross section for elastic e−p scattering in the range of momentum transfer from Q2=2.9 to 31.3 (GeV/c)2. Combined statistical and systematic uncertainties in the cross-section measurements ranged from 3% at low Q2 to 19% at high Q2. These data have been used to extract the proton magnetic form factor GMp(Q2). The results show a smooth decrease of Q4GMp with momentum transfer above Q2=10 (GeV/c)2. These results are compared with recent predictions of perturbative QCD.

14 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

Absolute electron Proton Cross-Sections at Low Momentum Transfer Measured with a High Pressure Gas Target System

Simon, G.G. ; Schmitt, C. ; Borkowski, F. ; et al.

Nucl.Phys.A 333 (1980) 381-391, 1980.

Inspire Record 157164 DOI 10.17182/hepdata.37069

Absolute differential cross sections for elastic electron-proton scattering have been measured in a four-momentum transfer range up to 1.4 fm −2 . Using a high pressure gas target system, we have obtained highly accurate data with a small normalization error of 0.5%. The electromagnetic form factors G E and G M have been extracted and the rms charge radius has been determined to be 〈r 2 E 〉 p 1 2 = 0.862±0.012 fm . The shape of the isovector spectral function near threshold shows a significant non-resonant contribution of the two-pion state. This enhancement is so strong that the derivative at q 2 = 0 differs considerably from the usual vector meson dominance model value. This result is in good agreement with theoretical predictions.

1 data table

Table 1

No description provided.