Date

Polarization transfer in proton Compton scattering at high momentum transfer.

The Jefferson Lab Hall A collaboration Hamilton, D.J. ; Mamyan, V.H. ; Aniol, K.A. ; et al.
Phys.Rev.Lett. 94 (2005) 242001, 2005.
Inspire Record 660894 DOI 10.17182/hepdata.19389

Compton scattering from the proton was investigated at s=6.9 (GeV/c)**2 and \t=-4.0 (GeV/c)**2 via polarization transfer from circularly polarized incident photons. The longitudinal and transverse components of the recoil proton polarization were measured. The results are in excellent agreement with a prediction based on a reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton and in disagreement with a prediction of pQCD based on a two-gluon exchange mechanism.

1 data table match query

Polarization transfer parameters.


Compton scattering cross section on the proton at high momentum transfer.

The Hall A collaboration Danagoulian, A. ; Mamyan, V.H. ; Roedelbronn, M. ; et al.
Phys.Rev.Lett. 98 (2007) 152001, 2007.
Inspire Record 743383 DOI 10.17182/hepdata.31472

Cross-section values for Compton scattering on the proton were measured at 25 kinematic settings over the range s = 5-11 and -t = 2-7 GeV2 with statistical accuracy of a few percent. The scaling power for the s-dependence of the cross section at fixed center of mass angle was found to be 8.0 +/ 0.2, strongly inconsistent with the prediction of perturbative QCD. The observed cross-section values are in fair agreement with the calculations using the handbag mechanism, in which the external photons couple to a single quark.

4 data tables match query

Cross section of proton Compton Scattering at centre of mass energy squared of 4.82 GeV.

Cross section of proton Compton Scattering at centre of mass energy squared of 6.79 GeV.

Cross section of proton Compton Scattering at centre of mass energy squared of 8.90 GeV.

More…

Diffraction Dissociation of Photons on Hydrogen

Chapin, T.J. ; Cool, R.L. ; Goulianos, Konstantin A. ; et al.
Phys.Rev.D 31 (1985) 17-30, 1985.
Inspire Record 216071 DOI 10.17182/hepdata.4332

We report results from a measurement of the inclusive diffraction dissociation of photons on hydrogen, γp→Xp, in the range 75<pγ<148 GeV/c, 0.02<‖t‖<0.1 (GeV/c)2, and MX2/s<0.1. Our data show an exponential t dependence and a dominant 1/MX2 behavior for MX2>4 GeV2. We test the finite-mass sum rule and, by comparing γp with π−p data obtained in the same apparatus, we test factorization.

14 data tables match query

EXTRACTED ELASTIC CROSS SECTIONS.

RESULTS OF EXPONENTIAL FITS TO ELASTIC CROSS SECTIONS.

DIFFERENTIAL CROSS SECTIONS FOR INELASTIC EVENTS.

More…

Kaon production in <math altimg="si1.gif"><ovl type="bar" style="s">p</ovl>p</math> reactions at a centre-of-mass energy of 540 GeV

The Bonn UA5 & Brussels UA5 & Cambridge UA5 & CERN UA5 & Stockholm UA5 collaborations Alner, G.J. ; Alpgard, K. ; Anderer, P. ; et al.
Nucl.Phys.B 258 (1985) 90624 505-539, 1985.
Inspire Record 214234 DOI 10.17182/hepdata.8127

Using the UA5 detector, the inclusive central production of Ks<sup loc="post">0</sup> and K<sup loc="post">±</sup> mesons has been measured in non-single-diffractive interactions at the CERN SPS <math altimg="si1.gif"><ovl type="bar" style="s">p</ovl>p</math> Collider at a c.m. energy of 540 GeV. The average transverse momentum is found to be 〈pT〉 = 0.57±0.03 GeV/c in the rapidity range |y|<2.5, which is an increase of about 30% over the top ISR energy. The K/π ratio has increased from about 8% at ISR energies to 9.5±0.9±0.7% (the last error is systematic) at 540 GeV. The average number of Ks<sup loc="post">0</sup> per non-single-diffractive event is 1.1±0.1 and the inclusive inelastic cross section is estimated at 49±5 mb.

1 data table match query

NON SINGLE DIFFRACTION CROSS SECTION.


Measurements of the electric and magnetic form-factors of the neutron from Q**2 = 1.75-GeV/c**2 to 4-GeV/c**2

Lung, A. ; Stuart, L.M. ; Bosted, Peter E. ; et al.
Phys.Rev.Lett. 70 (1993) 718-721, 1993.
Inspire Record 342252 DOI 10.17182/hepdata.19739

Quasielastic e-d cross sections have been measured at forward and backward angles. Rosenbluth separations were done to obtain RL and RT at Q2=1.75, 2.50, 3.25, and 4.00 (GeV/c)2. The neutron form factors GEn and GMn have been extracted using a nonrelativistic model. The sensitivity to deuteron wave function, relativistic corrections, and models of the inelastic background are reported. The results for GMn are consistent with the dipole form, while GEn is consistent with zero. Comparisons are made to theoretical models based on vector meson dominance, perturbative QCD, and QCD sum rules, as well as constituent quarks.

2 data tables match query

Magnetic form factors.

Electric form factors.


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

Bosted, Peter E. ; Clogher, L. ; Lung, A. ; et al.
Phys.Rev.Lett. 68 (1992) 3841-3844, 1992.
Inspire Record 332962 DOI 10.17182/hepdata.19849

The proton elastic electric and magnetic form factors, GEp(Q2) and GMp(Q2), have been separately measured in the range Q2=1.75 to 8.83 (GeV/c)2, more than doubling the Q2 range of previous data. Scaled by the dipole fit, GD(Q2), the results for GMp(Q2)/μpGD(Q2) decrease smoothly from 1.05 to 0.91, while GEp(Q2)/GD(Q2) is consistent with unity. Comparisons are made to QCD sum rule, diquark, constitutent quark, and vector meson dominance models, none of which agree with all of the new data. The ratio Q2F2/F1 approaches a constant value for Q2>3 (GeV/c)2.

2 data tables match query

Magnetic form factors.

Electric form factors.


Analyzing power measurements in high‐P2∥ p‐p elastic scattering

Raymond, R.S. ; Brown, K.A. ; Bruni, R.J. ; et al.
AIP Conf.Proc. 123 (1984) 1123-1125, 1984.
Inspire Record 201609 DOI 10.17182/hepdata.18612

The analyzing power in 28 GeV/c proton/proton elastic scattering was measured at P2∥=5.95 and 6.56 (GeV/c)2 using a polarized proton target and an unpolarized proton beam at the Brookhaven National Laboratory AGS. Results indicate that the analyzing power, A, is rising sharply with P2∥.

1 data table match query

No description provided.


High precision measurement of A in large P(T)**2 spin polarized 24-GeV/c proton proton elastic scattering

Crabb, D.G. ; Kaufman, W.A. ; Krisch, A.D. ; et al.
Phys.Rev.Lett. 65 (1990) 3241-3244, 1990.
Inspire Record 299843 DOI 10.17182/hepdata.19939

We measured the analyzing power A out to P⊥2=7.1 (GeV/c)2 with high precision by scattering a 24-GeV/c unpolarized proton beam from the new University of Michigan polarized proton target; the target’s 1-W cooling power allowed a beam intensity of more than 2×1011 protons per pulse. This high beam intensity together with the unexpectedly high average target polarization of about 85% allowed unusually accurate measurements of A at large P⊥2. These precise data confirmed that the one-spin parameter A is nonzero and indeed quite large at high P⊥2; most theoretical models predict that A should go to zero.

1 data table match query

Errors quoted contain both statistical and systematic uncertainties.


Measurement of the Analyzing Power for $p p$ (Polarized) $\to p p$ at $p^-$transverse**2 = 6.5-{GeV}/$c^2$

Cameron, P.R. ; Crabb, D.G. ; DeMuth, G.E. ; et al.
Phys.Rev.D 32 (1985) 3070, 1985.
Inspire Record 216507 DOI 10.17182/hepdata.23543

The spin analyzing power A in 28-GeV/c proton-proton elastic scattering was measured at P⊥2=6.5 (GeV/c)2 using a polarized proton target and a high-intensity unpolarized proton beam at the Brookhaven National Laboratory Alternating Gradient Synchrotron. The result of (24±8)% confirms that the analyzing power is large and rising in the large-P⊥2 region.

1 data table match query

No description provided.


Measurement of the Spin Parameters a and A(nn) in $p p$ Elastic Scattering in the 1-{GeV}/$c$ to 3-{GeV}/$c$ Region

Bell, D.A. ; Buchanan, J.A. ; Calkin, M.M. ; et al.
Phys.Lett.B 94 (1980) 310-314, 1980.
Inspire Record 153380 DOI 10.17182/hepdata.27194

We have measured the asymmetry parameter A and the spin correlation parameter A nn in pp elastic scattering, using the Argonne ZGS polarized proton beam and a polarized proton target. Angular distributions of A and A nn for | t | ≳ 0.2 (GeV/ c ) 2 were obtained at eight momenta between 1.10 and 2 if 2.75 GeV/ c . We find significant structure in both the energy and t -dependence of A nn at these energies. At p lab ≈ 1.34 GeV/ c A nn reaches a very large value of about 0.8–0.9 near θ cm = 90°.

8 data tables match query

No description provided.

No description provided.

No description provided.

More…