Williams, M.
Single Differential Cross Section
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Differential cross section and recoil polarization measurements for the gamma p to K+ Lambda reaction using CLAS at Jefferson Lab

The CLAS collaboration McCracken, M.E. ; Bellis, M. ; Meyer, C.A. ; et al.
Phys.Rev.C 81 (2010) 025201, 2010.
Inspire Record 840934 DOI 10.17182/hepdata.54967

We present measurements of the differential cross section and Lambda recoil polarization for the gamma p to K+ Lambda reaction made using the CLAS detector at Jefferson Lab. These measurements cover the center-of-mass energy range from 1.62 to 2.84 GeV and a wide range of center-of-mass K+ production angles. Independent analyses were performed using the K+ p pi- and K+ p (missing pi -) final-state topologies/ results from these analyses were found to exhibit good agreement. These differential cross section measurements show excellent agreement with previous CLAS and LEPS results and offer increased precision and a 300 MeV increase in energy coverage. The recoil polarization data agree well with previous results and offer a large increase in precision and a 500 MeV extension in energy range. The increased center-of-mass energy range that these data represent will allow for independent study of non-resonant K+ Lambda photoproduction mechanisms at all production angles.

241 data tables
Table 1

Differential cross section as a function of COS(THETA(K)) for the centre-of-mass range 1.62-1.63 GeV.

Table 2

Differential cross section as a function of COS(THETA(K)) for the centre-of-mass range 1.63-1.64 GeV.

Table 3

Differential cross section as a function of COS(THETA(K)) for the centre-of-mass range 1.64-1.65 GeV.

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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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Measurement of the reaction gamma p --> K0 Sigma+ at photon energies up to 2.6-GeV.

Lawall, R. ; Barth, J. ; Bennhold, C. ; et al.
Eur.Phys.J.A 24 (2005) 275-286, 2005.
Inspire Record 680746 DOI 10.17182/hepdata.43595

The reaction gamma p --> K0 Sigma+ was measured in the photon energy range from threshold up to 2.6 GeV with the SAPHIR detector at the electron stretcher facility, ELSA, in Bonn. Results are presented on the reaction cross section and the polarization of the Sigma+ as a function of the kaon production angle in the centre-of-mass system, cos(Theta_K^{c.m.}), and the photon energy. The cross section is lower and varies less with photon energy and kaon production angle than that of gamma p --> K+ Sigma0. The Sigma+ is polarized predominantly at cos(Theta_K^{c.m.}) \approx 0. The data presented here are more precise than previous ones obtained with SAPHIR and extend the photon energy range to higher values. They are compared to isobar model calculations.

14 data tables
Table 1

Axis error includes +- 10/10 contribution (Normalization uncertainty already included.).

Table 2

Axis error includes +- 10/10 contribution (Normalization uncertainty already included.).

Table 3

Axis error includes +- 10/10 contribution (Normalization uncertainty already included.).

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Measurement of gamma p --> K+ Lambda and gamma p --> K+ Sigma0 at photon energies up to 2.6 GeV

Glander, K.H. ; Barth, J. ; Braun, W. ; et al.
Eur.Phys.J.A 19 (2004) 251-273, 2004.
Inspire Record 626695 DOI 10.17182/hepdata.51677

The reactions gamma p --> K+ Lambda and gamma p --> K+ Sigma0 were measured in the energy range from threshold up to a photon energy of 2.6 GeV. The data were taken with the SAPHIR detector at the electron stretcher facility, ELSA. Results on cross sections and hyperon polarizations are presented as a function of kaon production angle and photon energy. The total cross section for Lambda production rises steeply with energy close to threshold, whereas the Sigma0 cross section rises slowly to a maximum at about E_gamma = 1.45 GeV. Cross sections together with their angular decompositions into Legendre polynomials suggest contributions from resonance production for both reactions. In general, the induced polarization of Lambda has negative values in the kaon forward direction and positive values in the backward direction. The magnitude varies with energy. The polarization of Sigma0 follows a similar angular and energy dependence as that of Lambda, but with opposite sign.

24 data tables
Table 1

Differential cross sections for the reaction GAMMA P --> K+ LAMBDA in the energy region 0.9 to 1.0 GeV.

Table 2

Differential cross sections for the reaction GAMMA P --> K+ LAMBDA in the energy region 1.0 to 1.2 GeV.

Table 3

Differential cross sections for the reaction GAMMA P --> K+ LAMBDA in the energy region 1.2 to 1.4 GeV.

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MEASUREMENT OF POLARIZATION PARAMETERS FOR THE PI- P ---> PI0 N CHARGE EXCHANGE SCATTERING FROM 1965-MEV/C TO 4220-MEV/C

Minowa, M. ; Adachi, T. ; Daigo, M. ; et al.
Nucl.Phys.B 294 (1987) 979-1000, 1987.
Inspire Record 255228 DOI 10.17182/hepdata.33402

Polarization parameters for the π − p → π 0 n charge exchange scattering have been measured at eight beam momenta between 1965 and 4220 MeV/ c using two different experimental set-ups. The angular range covered is −0.90 < cos θ π ∗ < 0.95 at the five momenta of 1965, 2168, 2360, 2566 and 2960 MeV/ c , where θ π ∗ is the emission angle of the π 0 meson in the c.m.s.. For three momenta of 2770, 3490 and 4220 MeV/ c , the measurements cover the forward angles of 0.1 < cos θ π ∗ < 1.0 . The results are compared with the predictions of π N partial wave analyses.

4 data tables
Table 1

Polarisation measurements from SETUP1. Errors are statistical only.

Table 2

Polarisation measurements from SETUP2. Errors are statistical only.

Table 3

Legendre polynomial coefficients for fit to differential cross section data.

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The Reaction anti-p p --> anti-Lambda Lambda Between 1.50-GeV/c and 2.06-GeV/c

Jayet, B. ; Gailloud, M. ; Rosselet, P. ; et al.
Nuovo Cim.A 45 (1978) 371-388, 1978.
Inspire Record 135059 DOI 10.17182/hepdata.37573

The reaction\(\bar pp \to \bar \Lambda \Lambda \) has been studied in a bubble chamber experiment at eight incident momenta between 1.50 and 2.06 GeV/c. The differential cross-section, the polarization and the spin correlation coefficients have been measured. They have been compared with the prediction of two theoretical models: the K-meson conspiracy and the exchange of the K*K** degenerate trajectory associated with a Regge cut. The latter model gives the best representation of the data.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

POLARIZATION AND SPIN CORRELATION COEFFICIENTS. AVERAGED OVER ALL ANGLES. SEE PAPER FOR DEFINITIONS, MORE DETAILS AND POSSIBLE T-DEPENDENCE.


Measurement of the Polarization Parameter for anti-Proton-Proton Annihilation Into Charged Pion and Kaon Pairs Between 1.0-GeV/c and 2.2-GeV/c

Carter, A.A. ; Coupland, M. ; Eisenhandler, E. ; et al.
Nucl.Phys.B 127 (1977) 202, 1977.
Inspire Record 119216 DOI 10.17182/hepdata.8355

The polarization parameter P for the reactions p p → π − π + and p p → K − K + has been measured over essentially the full angular range at ll laboratory momenta between 1.0 and 2.2. GeV/ c , using a proton target polarized perpendicular to the scattering plane. The angles and momenta of both final state particles were determined from wire spark chambers, using the deflection caused by the polarized target magnet. Between 1000 and 5300 π − π + events, and 140 and 1300 K − K + events, were measured at each momentum. Differential cross sections for p p → π − π + were obtained. These are in excellent agreement with previous results. The polarization parameter for both channels is very close to +1 over much of the angular range. Legendre polynomial fits to the data are presented.

12 data tables
Table 1

THE DIFFERENTIAL CROSS SECTIONS IN THIS EXPERIMENT AGREE WITH THE ONES FROM THE AUTHORS' EARLIER EXPERIMENT (E. EISENHANDLER ET AL., NP B96, 109(1975)) USING A LIQUID HYDROGEN TARGET, THOUGH THEY DO NOT CONSIDER THE PRESENT ONES QUITE AS RELIABLE.

Table 2

No description provided.

Table 3

No description provided.

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A Study of the Reactions anti-K0 p ---> Lambda pi+ and anti-K0 p ---> Sigma0 pi+ from 1-GeV/c to 12-GeV/c

Yamartino, R. ; Brandenburg, G.W. ; Johnson, William B. ; et al.
Phys.Rev.D 10 (1974) 9, 1974.
Inspire Record 91647 DOI 10.17182/hepdata.24927

Cross sections, differential cross sections, and hyperon polarization results are presented for the reactions K¯0p→Λπ+ and K¯0p→Σ0π+ in the momentum interval 1 to 12 GeV/c. Emphasis is placed on the comparison of Λ and Σ channels, and on the momentum dependences of the data. In particular, the Λ polarization data are consistent with being independent of energy above 2 GeV/c; and the slopes of the forward cross sections are found to increase toward the slope values for the line-reversed reactions πp→K(Λ,Σ) as energy increases.

27 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

RESONANCE REGION CROSS SECTIONS.

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