Sorokin, P.V.
Polarization
[1.0, 2.0]
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Angular dependence of the asymmetry of the cross section for the reaction $\gamma$p $\rightarrow$ $\Delta^{++}\pi^{-}$ at a photon energy 650 MeV

Ganenko, V.B. ; Gorbenko, V.B. ; Zhebrovskii, Yu.V. ; et al.
JETP Lett. 16 (1972) 310-312, 1972.
Inspire Record 1393130 DOI 10.17182/hepdata.39786

None

1 data table
Table 1

No description provided.


Separated structure functions for the exclusive electroproduction of K+ Lambda and K+ Sigma0 final states.

The CLAS collaboration Ambrozewicz, P. ; Carman, D.S. ; Feuerbach, R.J. ; et al.
Phys.Rev.C 75 (2007) 045203, 2007.
Inspire Record 732363 DOI 10.17182/hepdata.4994

We report measurements of the exclusive electroproduction of $K^+\Lambda$ and $K^+\Sigma^0$ final states from a proton target using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The separated structure functions $\sigma_T$, $\sigma_L$, $\sigma_{TT}$, and $\sigma_{LT}$ were extracted from the $\Phi$- and $\epsilon$-dependent differential cross sections taken with electron beam energies of 2.567, 4.056, and 4.247 GeV. This analysis represents the first $\sigma_L/\sigma_T$ separation with the CLAS detector, and the first measurement of the kaon electroproduction structure functions away from parallel kinematics. The data span a broad range of momentum transfers from $0.5\leq Q^2\leq 2.8$ GeV$^2$ and invariant energy from $1.6\leq W\leq 2.4$ GeV, while spanning nearly the full center-of-mass angular range of the kaon. The separated structure functions reveal clear differences between the production dynamics for the $\Lambda$ and $\Sigma^0$ hyperons. These results provide an unprecedented data sample with which to constrain current and future models for the associated production of strangeness, which will allow for a better understanding of the underlying resonant and non-resonant contributions to hyperon production.

531 data tables
Table 1

Cross sections for incident energy 2.567 GeV for the Q**2 range 0.5 to 0.8 GeV**2 and W range 1.6 to 1.7 GeV.

Table 2

Cross sections for incident energy 2.567 GeV for the Q**2 range 0.5 to 0.8 GeV**2 and W range 1.70 to 1.75 GeV.

Table 3

Cross sections for incident energy 2.567 GeV for the Q**2 range 0.5 to 0.8 GeV**2 and W range 1.75 to 1.80 GeV.

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First measurement of beam-recoil observables C(x) and C(z) in hyperon photoproduction.

The CLAS collaboration Bradford, R.K. ; Schumacher, R.A. ; Adams, G. ; et al.
Phys.Rev.C 75 (2007) 035205, 2007.
Inspire Record 732402 DOI 10.17182/hepdata.31496

Spin transfer from circularly polarized real photons to recoiling hyperons has been measured for the reactions $\vec\gamma + p \to K^+ + \vec\Lambda$ and $\vec\gamma + p \to K^+ + \vec\Sigma^0$. The data were obtained using the CLAS detector at Jefferson Lab for center-of-mass energies $W$ between 1.6 and 2.53 GeV, and for $-0.85<\cos\theta_{K^+}^{c.m.}< +0.95$. For the $\Lambda$, the polarization transfer coefficient along the photon momentum axis, $C_z$, was found to be near unity for a wide range of energy and kaon production angles. The associated transverse polarization coefficient, $C_x$, is smaller than $C_z$ by a roughly constant difference of unity. Most significantly, the {\it total} $\Lambda$ polarization vector, including the induced polarization $P$, has magnitude consistent with unity at all measured energies and production angles when the beam is fully polarized. For the $\Sigma^0$ this simple phenomenology does not hold. All existing hadrodynamic models are in poor agreement with these results.

34 data tables
Table 1

Coefficients Cx and Cz for the reaction GAMMA P --> K+ LAMBDA for incident energy = 1.032 GeV and W = 1.679 GeV.

Table 2

Coefficients Cx and Cz for the reaction GAMMA P --> K+ LAMBDA for incident energy = 1.132 GeV and W = 1.734 GeV.

Table 3

Coefficients Cx and Cz for the reaction GAMMA P --> K+ LAMBDA for incident energy = 1.232 GeV and W = 1.787 GeV.

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Deeply virtual and exclusive electroproduction of omega mesons.

The CLAS collaboration Morand, L. ; Dore, D. ; Garcon, M. ; et al.
Eur.Phys.J.A 24 (2005) 445-458, 2005.
Inspire Record 681604 DOI 10.17182/hepdata.43499

The exclusive omega electroproduction off the proton was studied in a large kinematical domain above the nucleon resonance region and for the highest possible photon virtuality (Q2) with the 5.75 GeV beam at CEBAF and the CLAS spectrometer. Cross sections were measured up to large values of the four-momentum transfer (-t < 2.7 GeV2) to the proton. The contributions of the interference terms sigma_TT and sigma_TL to the cross sections, as well as an analysis of the omega spin density matrix, indicate that helicity is not conserved in this process. The t-channel pi0 exchange, or more generally the exchange of the associated Regge trajectory, seems to dominate the reaction gamma* p -> omega p, even for Q2 as large as 5 GeV2. Contributions of handbag diagrams, related to Generalized Parton Distributions in the nucleon, are therefore difficult to extract for this process. Remarkably, the high-t behaviour of the cross sections is nearly Q2-independent, which may be interpreted as a coupling of the photon to a point-like object in this kinematical limit.

85 data tables
Table 1

Total cross sections and interference terms (TT and TL).

Table 2

Differential cross sections DSIG/DT for Q**2 = 1.725 GeV**2 and W = 2.77 GeV.

Table 3

Differential cross sections DSIG/DT for Q**2 = 1.752 GeV**2 and W = 2.48 GeV.

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Proton-proton spin correlation measurements at 200 MeV with an internal target in a storage ring

Haeberli, W. ; Lorentz, B. ; Rathmann, F. ; et al.
Phys.Rev.C 55 (1997) 597-613, 1997.
Inspire Record 464240 DOI 10.17182/hepdata.25711

Measurements of the pp spin correlation coefficients Axx, Ayy, and Axz and analyzing power Ay for pp elastic scattering at 197.8 MeV over the angular range 4.5°–17.5° have been carried out. The statistical accuracy is approximately ±0.01 for Amn and ±0.004 for Ay, while the corresponding scale factor uncertainties are 2.4% and 1.3%, respectively. The experiment makes use of a polarized hydrogen gas target internal to a proton storage ring (IUCF Cooler) and a circulating beam of polarized protons. The target polarization (Q=0.79) is switched in sign and in direction (x,y,z) every 2 s by reversing a weak guide field (about 0.3 mT). The forward-scattered protons are detected in two sets of wire chambers and a scintillator, while recoil protons are detected in coincidence with the forward protons by silicon strip detectors placed 5 cm from the proton beam. The background rate from scattering by the walls of the target cell is (0.2±0.2)% of the good event rate. Analysis methods and comparisons with pp potential models and pp partial wave analyses are described.

1 data table
Table 1

No description provided.


Absolute measurement of the p+p analyzing power at 183 MeV

von Przewoski, B. ; Meyer, H.O. ; Pancella, P.V. ; et al.
Phys.Rev.C 44 (1991) 44-49, 1991.
Inspire Record 327386 DOI 10.17182/hepdata.26154

The analyzing power Ay for p+p elastic scattering at θlab=8.64°±0.07° (θcms=18.1°) and at a bombarding energy of 183.1±0.4 MeV has been determined to be Ay=0.2122±0.0017. The error includes statistics, systematic uncertainties, and the uncertainty in bombarding energy and angle. This measurement represents a calibration standard for polarized beams in this energy range. The absolute scale for the measurement has been obtained by comparison with p+C elastic scattering at the same energy at an angle where Ay is very nearly unity.

1 data table
Table 1

Axis error includes +- 0.0/0.0 contribution (?////).


MEASUREMENT OF THE POLARIZATION H PARAMETER IN REACTION GAMMA P ---> PI+ N WITH 320-MEV PHOTONS. (IN RUSSIAN)

Belyaev, A.A. ; Getman, V.A. ; Glamazdin, A.V. ; et al.
Yad.Fiz. 43 (1986) 1469-1471, 1986.
Inspire Record 238218 DOI 10.17182/hepdata.17579

None

1 data table
Table 1

No description provided.


MEASUREMENT OF POLARIZATION OF PROTONS FROM REACTION GAMMA P ---> P PI0 IN THE THIRD RESONANCE. (IN RUSSIAN)

Bratashevsky, A.S. ; Zybalov, A.A. ; Karasev, S.P. ; et al.
Yad.Fiz. 41 (1985) 1515-1519, 1985.
Inspire Record 227501 DOI 10.17182/hepdata.17615

None

2 data tables
Table 1

No description provided.

Table 2

No description provided.


MEASUREMENT OF POLARIZATION OF PROTONS FROM THE REACTION GAMMA P ---> P PI0 AT THETA (PI) = 110-DEGREES C.M. IN THE RANGE OF THE SECOND AND THIRD RESONANCES. (IN RUSSIAN)

Bratashevsky, A.S. ; Zybalov, A.A. ; Karasev, S.P. ; et al.
Yad.Fiz. 42 (1985) 658-663, 1985.
Inspire Record 221959 DOI 10.17182/hepdata.17612

None

1 data table
Table 1

No description provided.


EXPERIMENTAL STUDIES OF THE SIGMA, T, P POLARIZATION PARAMETERS AND THE GAMMA P ---> P PI0 REACTION MULTIPOLE ANALYSIS IN THE FIRST RESONANCE REGION

Belyaev, A.a. ; Getman, V.a. ; Gorbenko, V.g. ; et al.
Nucl.Phys.B 213 (1983) 201-222, 1983.
Inspire Record 192457 DOI 10.17182/hepdata.34021

A description is given of the experimental techniques and investigation results of the parameters Σ , T , P for the γ p→p π 0 reaction using linear polarized photons and a polarized proton target. The measurements have been made in the photon energy range 280–450 MeV at pion c.m. angles between 60° and 135°. The new experimental data are used in an energy-independent channel multipole analysis without the Watson theorem.

8 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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