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The Reaction $p + p \rightarrow p + p + {\pi}^0$ in the Energy Range from Threshold to 665 MeV

Dunaitsev, A.F. ; Prokoshkin, Yu.D. ;
Sov.Phys.JETP 9 (1959) 1179, 1959.
Inspire Record 1408597 DOI 10.17182/hepdata.70460

None

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Forward $\pi^-p$ charge exchange scattering between 0.8 and 1.9 GeV

Borgeaud, P. ; Bruneton, C. ; Ducros, Y. ; et al.
Phys.Lett. 10 (1964) 134-137, 1964.
Inspire Record 1400914 DOI 10.17182/hepdata.31224

None

15 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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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.

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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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Photoproduction of $\eta$ and $\eta\prime$ Mesons off Protons

The CBELSA/TAPS collaboration Crede, V. ; McVeigh, A. ; Anisovich, A.V. ; et al.
Phys.Rev.C 80 (2009) 055202, 2009.
Inspire Record 836340 DOI 10.17182/hepdata.53229

Total and differential cross sections for $\eta$ and $\eta ^\prime$ photoproduction off the proton have been determined with the CBELSA/TAPS detector for photon energies between 0.85 and 2.55 GeV. The $\eta$ mesons are detected in their two neutral decay modes, $\eta\to\gamma\gamma$ and $\eta\to 3\pi^0\to 6\gamma$, and for the first time, cover the full angular range in $\rm cos \theta_{cm}$ of the $\eta$ meson. These new $\eta$ photoproduction data are consistent with the earlier CB-ELSA results. The $\eta ^\prime$ mesons are observed in their neutral decay to $\pi^0\pi^0\eta\to 6\gamma$ and also extend the coverage in angular range.

56 data tables
Table 1

Differential cross section for ETA production at incident photon energy 0.850 to 0.900 GeV.

Table 2

Differential cross section for ETA production at incident photon energy 0.900 to 0.950 GeV.

Table 3

Differential cross section for ETA production at incident photon energy 0.950 to 1.000 GeV.

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Differential cross sections for the reactions gamma p-> p eta and gamma p -> p eta-prime

The CLAS collaboration Williams, M. ; Krahn, Z. ; Applegate, D. ; et al.
Phys.Rev.C 80 (2009) 045213, 2009.
Inspire Record 830257 DOI 10.17182/hepdata.52983

High-statistics differential cross sections for the reactions gamma p -> p eta and gamma p -> p eta-prime have been measured using the CLAS at Jefferson Lab for center-of-mass energies from near threshold up to 2.84 GeV. The eta-prime results are the most precise to date and provide the largest energy and angular coverage. The eta measurements extend the energy range of the world's large-angle results by approximately 300 MeV. These new data, in particular the eta-prime measurements, are likely to help constrain the analyses being performed to search for new baryon resonance states.

104 data tables
Table 1

Differential cross section for the W range 1.68 to 1.69 GeV.

Table 2

Differential cross section for the W range 1.69 to 1.70 GeV.

Table 3

Differential cross section for the W range 1.70 to 1.71 GeV.

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Differential cross sections and spin density matrix elements for the reaction $\gamma p \to p \omega$

The CLAS collaboration Williams, M. ; Applegate, D. ; Bellis, M. ; et al.
Phys.Rev.C 80 (2009) 065208, 2009.
Inspire Record 829180 DOI 10.17182/hepdata.52667

High-statistics differential cross sections and spin density matrix elements for the reaction $\gamma p \to p \omega$ have been measured using the CLAS at Jefferson Lab for center-of-mass (CM) energies from threshold up to 2.84 GeV. Results are reported in 112 10-MeV wide CM energy bins, each subdivided into $\cos{\theta_{CM}^{\omega}}$ bins of width 0.1. These are the most precise and extensive $\omega$ photoproduction measurements to date. A number of prominent structures are clearly present in the data. Many of these have not previously been observed due to limited statistics in earlier measurements.

221 data tables
Table 1

Differential cross section for the W range 1.72 to 1.73 GeV.

Table 2

Differential cross section for the W range 1.73 to 1.74 GeV.

Table 3

Differential cross section for the W range 1.74 to 1.75 GeV.

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Measurement of the incoherent $\gamma d \to \phi p n$ photoproduction near threshold

The LEPS collaboration Chang, W.C. ; Miyabe, M. ; Nakano, T. ; et al.
Phys.Lett.B 684 (2010) 6-10, 2010.
Inspire Record 825381 DOI 10.17182/hepdata.54640

We report measurements of differential cross sections and decay asymmetries of incoherent $\phi$-meson photoproduction from the deuteron at forward angles using linearly polarized photons at \Eg=1.5-2.4 GeV. The nuclear transparency ratio for the deuteron shows a large suppression, and is consistent with the A-dependence of the ratio observed in a previous measurement with nuclear targets. The reduction for the deuteron cannot be adequately explained in term of isospin asymmetry. The present results suggest the need of refining our understanding of the $\phi$-N interaction within a nucleus.

7 data tables
Table 1

Distribution of DSIG/DT from incoherent reaction GAMMA DEUT --> PHI P N for the incident photon energy ranges 1.57 to 1.67 and 1.67 to 1.77 GeV.

Table 2

Distribution of DSIG/DT from incoherent reaction GAMMA DEUT --> PHI P N for the incident photon energy ranges 1.77 to 1.87 and 1.87 to 1.97 GeV.

Table 3

Distribution of DSIG/DT from incoherent reaction GAMMA DEUT --> PHI P N for the incident photon energy ranges 1.97 to 2.07 and 2.07 to 2.17 GeV.

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Near-threshold photoproduction of $\Lambda(1520)$ from protons and deuterons

Muramatsu, N. ; Chen, J.Y. ; Chang, W.C. ; et al.
Phys.Rev.Lett. 103 (2009) 012001, 2009.
Inspire Record 817890 DOI 10.17182/hepdata.22937

Photoproduction of $\Lambda$(1520) with liquid hydrogen and deuterium targets was examined at photon energies below 2.4 GeV in the SPring-8/LEPS experiment. For the first time, the differential cross sections were measured at low energies and with a deuterium target. A large asymmetry of the production cross sections from protons and neutrons was observed at backward K$^{+/0}$ angles. This suggests the importance of the contact term, which coexists with t-channel K exchange under gauge invariance. This interpretation was compatible with the differential cross sections, decay asymmetry, and photon beam asymmetry measured in the production from protons at forward K$^+$ angles.

4 data tables
Table 1

The measured differential cross sections from the liquid hydrogen target, protons, as a function the K+ polar angle.

Table 2

The measured differential cross sections from the liquid hydrogen target, protons, as a function the photon energy at forward K+ polar angles of 19-43 degrees .

Table 3

The measured of differential cross section at backward K+/K0 polar angles of 120-150 degrees as a function of photon energy from the liquid hydrogen target, protons, and liquid deuterium target, deuterons.

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$\pi^+$ photoproduction on the proton for photon energies from 0.725 to 2.875 GeV

The CLAS collaboration Dugger, M. ; Ritchie, B.G. ; Ball, J.P. ; et al.
Phys.Rev.C 79 (2009) 065206, 2009.
Inspire Record 814847 DOI 10.17182/hepdata.51952

Differential cross sections for the reaction $\gamma p \to n \pi^+$ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam with energies from 0.725 to 2.875 GeV. Where available, the results obtained here compare well with previously published results for the reaction. Agreement with the SAID and MAID analyses is found below 1 GeV. The present set of cross sections has been incorporated into the SAID database, and exploratory fits have been made up to 2.7 GeV. Resonance couplings have been extracted and compared to previous determinations. With the addition of these cross sections to the world data set, significant changes have occurred in the high-energy behavior of the SAID cross-section predictions and amplitudes.

11 data tables
Table 1

Differential cross sections for incident photon energies 0.725, 0.775, 0.825and 0.875 GeV.

Table 2

Differential cross sections for incident photon energies 0.925, 0.975, 1.025and 1.075 GeV.

Table 3

Differential cross sections for incident photon energies 1.125, 1.175, 1.225and 1.275 GeV.

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Study of the reaction $\gamma p\to p\pi^0\eta$

The CB-ELSA collaboration Horn, I. ; Anisovich, A.V. ; Anton, G. ; et al.
Eur.Phys.J.A 38 (2008) 173-186, 2008.
Inspire Record 789175 DOI 10.17182/hepdata.54384

The reaction $\gamma p\to p\pi^0\eta$ has been studied with the CBELSA detector at the tagged photon beam of the Bonn electron stretcher facility. The reaction shows contributions from $\Delta^+(1232)\eta$, $N(1535)^+\pi^0$ and $pa_0(980)$ as intermediate states. A partial wave analysis suggests that the reaction proceeds via formation of six $\Delta$ resonances, $\Delta(1600)P_{33}$, $\Delta(1920)P_{33}$, $\Delta(1700)D_{33}$, $\Delta(1940)D_{33}$, $\Delta(1905)F_{35}$, $\Delta(2360)D_{33}$, and two nucleon resonances $N(1880)P_{11}$ and $N(2200)P_{13}$, for which pole positions and decay branching ratios are given.

7 data tables
Table 1

Total cross section for GAMMA P --> P PI0 ETA.

Table 2

Differential cross sections as a function of the angles of the individual final state particles for the W range 1.7 to 1.9 GeV.. Errors shown are statistical only.

Table 3

Differential cross sections as a function of the angles of the individual final state particles for the W range 1.9 to 2.1 GeV.. Errors shown are statistical only.

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Photoproduction of Lambda(1405) and Sigma^{0}(1385) on the proton at E_\gamma = 1.5-2.4 GeV

Niiyama, M. ; Fujimura, H. ; Ahn, D.S. ; et al.
Phys.Rev.C 78 (2008) 035202, 2008.
Inspire Record 786670 DOI 10.17182/hepdata.50883

Differential cross sections for $\gamma p \to K^+\Lambda(1405)$ and $\gamma p \to K^+\Sigma^0(1385)$ reactions have been measured in the photon energy range from 1.5 to 2.4 GeV and the angular range of $0.8<\cos(\Theta)<1.0$ for the $K^+$ scattering angle in the center-of-mass system. This data is the first measurement of the $\Lambda(1405)$ photoproduction cross section. The lineshapes of \LamS measured in $\Sigma^+\pi^-$ and $\Sigma^-\pi^+$ decay modes were different with each other, indicating a strong interference of the isospin 0 and 1 terms of the $\Sigma\pi$ scattering amplitudes. The ratios of \LamS production to \SigS production were measured in two photon energy ranges: near the production threshold ($1.5<E_\gamma<2.0$ GeV) and far from it ($2.0 <E_\gamma<2.4$ GeV). The observed ratio decreased in the higher photon energy region, which may suggest different production mechanisms and internal structures for these hyperon resonances.

2 data tables
Table 1

Cross section for LAMBDA(1405) production.

Table 2

Cross section for SIGMA(1385)0 production.


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.

29 data tables
Table 1

Differential cross section for W = 0.61, 0.63 and 0.65 GeV.

Table 2

Differential cross section for W = 0.67, 0.69 and 0.71 GeV.

Table 3

Differential cross section for W = 0.73, 0.75 and 0.77 GeV.

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Quasi-free photoproduction of eta-mesons of the neutron

The CBELSA & TAPS collaborations Jaegle, I. ; Mertens, T. ; Anisovich, A.V. ; et al.
Phys.Rev.Lett. 100 (2008) 252002, 2008.
Inspire Record 784698 DOI 10.17182/hepdata.50884

Quasi-free photoproduction of eta-mesons off nucleons bound in the deuteron has been measured with the CBELSA/TAPS detector for incident photon energies up to 2.5 GeV at the Bonn ELSA accelerator. The eta-mesons have been detected in coincidence with recoil protons and recoil neutrons, which allows a detailed comparison of the quasi-free n(gamma,eta)n and p(gamma,eta)p reactions. The excitation function for eta-production off the neutron shows a pronounced bump-like structure at W=1.68 GeV (E_g ~ 1 GeV), which is absent for the proton.

22 data tables
Table 1

Measured value of the quasi-free eta cross section off protons and neutrons as a function of incident photon energy.

Table 2

Ratio of the measured quasi-free neutron to proton cross sections as a function of incident photon energy.

Table 3

Measured angular distribution for an incident photon energy of 0.700 GeV.

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K^0 pi^0 Sigma^+ and K^*0 Sigma^+ photoproduction off the proton

The CBELSA/TAPS collaboration Nanova, M. ; Bacelar, J.C.S. ; Bantes, B. ; et al.
Eur.Phys.J.A 35 (2008) 333-342, 2008.
Inspire Record 781382 DOI 10.17182/hepdata.51372

The exclusive reactions $\gamma p \to K^{*0} \Sigma^+(1189)$ and $\gamma p \to K^{0} \pi^{0}\Sigma^+(1189)$, leading to the p 4$\pi^{0}$ final state, have been measured with a tagged photon beam for incident energies from threshold up to 2.5 GeV. The experiment has been performed at the tagged photon facility of the ELSA accelerator (Bonn). The Crystal Barrel and TAPS detectors were combined to a photon detector system of almost 4$\pi$ geometrical acceptance. Differential and total cross sections are reported. At energies close to the threshold, a flat angular distribution has been observed for the reaction $\gamma p\to K^{0} \pi^{0}\Sigma^+$ suggesting dominant s-channel production. $\Sigma^*(1385)$ and higher lying hyperon states have been observed. An enhancement in the forward direction in the angular distributions of the reaction $\gamma p \to K^{*0}\Sigma^+$ indicates a $t$-channel exchange contribution to the reaction mechanism. The experimental data are in reasonable agreement with recent theoretical predictions.

13 data tables
Table 1

Differential cross section D(SIG)/DCOS(THETA(SIG+)) for the GAMMA P --> K0 PI0 SIGMA+ reaction for beam energies 1500-1700 and 1700-1850 MeV.

Table 2

Differential cross section D(SIG)/DCOS(THETA(SIG+)) for the GAMMA P --> K0 PI0 SIGMA+ reaction for beam energies 1850-2000 and 2000-2150 MeV.

Table 3

Differential cross section D(SIG)/DCOS(THETA(SIG+)) for the GAMMA P --> K0 PI0 SIGMA+ reaction for beam energies 2150-2300 and 2300-2500 MeV.

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Electroproduction of $\phi(1020)$ mesons at $1.4\leq Q^2\leq$ 3.8 GeV$^2$ measured with the CLAS spectrometer

The CLAS collaboration Santoro, J.P. ; Smith, E.S. ; Garc con, M. ; et al.
Phys.Rev.C 78 (2008) 025210, 2008.
Inspire Record 781974 DOI 10.17182/hepdata.50913

Electroproduction of exclusive $\phi$ vector mesons has been studied with the CLAS detector in the kinematical range $1.6\leq Q^2\leq 3.8$ GeV$^{2}$, $0.0\leq t^{\prime}\leq 3.6$ GeV$^{2}$, and $2.0\leq W\leq 3.0$ GeV. The scaling exponent for the total cross section as $1/(Q^2+M_{\phi}^2)^n$ was determined to be $n=2.49\pm 0.33$. The slope of the four-momentum transfer $t'$ distribution is $b_{\phi}=0.98 \pm 0.17$ GeV$^{-2}$. The data are consistent with the assumption of s-channel helicity conservation (SCHC). Under this assumption, we determine the ratio of longitudinal to transverse cross sections to be $R=0.86 \pm 0.24$. A 2-gluon exchange model is able to reproduce the main features of the data.

5 data tables
Table 1

Axis error includes +- 18.6/18.6 contribution.

Table 2

Axis error includes +- 18.6/18.6 contribution.

Table 3

Axis error includes +- 18.6/18.6 contribution.

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Measurement of the $\vec{\gamma} p \to K^+ \Lambda$ Reaction at Backward Angles

The LEPS collaboration Hicks, K. ; Mibe, T. ; Sumihama, M. ; et al.
2007.
Inspire Record 756925 DOI 10.17182/hepdata.25090

Cross sections for the $\gamma p \to K^+ \Lambda$ have been measured at backward angles using linearly polarized photons in the range 1.50 to 2.37 GeV. In addition, the beam asymmetry for this reaction has been measured for the first time at backward angles. The $\Lambda$ was detected at forward angles in the LEPS spectrometer via its decay to $p\pi^-$ and the K^+ was inferred using the technique of missing mass. These measurements, corresponding to kaons at far backward angles in the center-of-mass frame, complement similar CLAS data at other angles. Comparison with theoretical models shows that the reactions in these kinematics provide further opportunities to investigate the reaction mechanisms of hadron dynamics.

5 data tables
Table 1

Differential cross sections as a function of the Mandelstam variable U for photon beam energy 1.5 to 1.8 GeV.

Table 2

Differential cross sections as a function of the Mandelstam variable U for photon beam energy 1.8 to 2.1 GeV.

Table 3

Differential cross sections as a function of the Mandelstam variable U for photon beam energy 2.1 to 2.4 GeV.

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Photoproduction of pi0 omega off protons for E(gamma) < 3-GeV.

The CB-ELSA collaboration Junkersfeld, J. ; Anisovich, A.V. ; Anton, G. ; et al.
Eur.Phys.J.A 31 (2007) 365-372, 2007.
Inspire Record 748502 DOI 10.17182/hepdata.43511

Differential and total cross-sections for photoproduction of gamma proton to proton pi0 omega and gamma proton to Delta+ omega were determined from measurements of the CB-ELSA experiment, performed at the electron accelerator ELSA in Bonn. The measurements covered the photon energy range from the production threshold up to 3GeV.

18 data tables
Table 1

Differential cross section as a function of the OMEGA angle.

Table 2

Differential cross section as a function of the OMEGA angle.

Table 3

Differential cross section as a function of the PI0 angle.

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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
Table 1

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

Table 2

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

Table 3

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

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Cross Sections for the $\gamma p \to K^{*0}\Sigma^+$ Reaction at $E_\gamma = 1.7 - 3.0$ GeV

The CLAS collaboration Hleiqawi, I. ; Hicks, K. ; Carman, D.S. ; et al.
Phys.Rev.C 75 (2007) 042201, 2007.
Inspire Record 742894 DOI 10.17182/hepdata.52647

Differential cross sections for the reaction $\gamma p \to K^{*0} \Sigma^+$ are presented at nine bins in photon energy in the range from 1.7 to 3.0 GeV. The \kstar was detected by its decay products, $K^+\pi^-$, in the CLAS detector at Jefferson Lab. These data are the first \kstar photoproduction cross sections ever published over a broad range of angles. Comparison with a theoretical model based on the vector and tensor $K^*$-quark couplings shows good agreement with the data in general, after adjusting the model's two parameters in a fit to our data. Disagreement between the data at forward angles and the global angle-energy fit to the model suggests that the role of scalar $\kappa$ meson exchange in $t$-channel diagrams should be investigated.

2 data tables
Table 1

Cross sections with total uncertainties.

Table 2

Cross sections with total uncertainties.


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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Determination of the Charged Pion Form Factor at Q2=1.60 and 2.45 (GeV/c)2

The Jefferson Lab F(pi)-2 collaboration Horn, T. ; Aniol, K. ; Arrington, J. ; et al.
Phys.Rev.Lett. 97 (2006) 192001, 2006.
Inspire Record 721062 DOI 10.17182/hepdata.31560

The H(e,e'pi+)n cross section was measured at four-momentum transfers of Q2=1.60 and 2.45 GeV2 at an invariant mass of the photon nucleon system of W=2.22 GeV. The charged pion form factor (F_pi) was extracted from the data by comparing the separated longitudinal pion electroproduction cross section to a Regge model prediction in which F_pi is a free parameter. The results indicate that the pion form factor deviates from the charge-radius constrained monopole form at these values of Q2 by one sigma, but is still far from its perturbative Quantum Chromo-Dynamics prediction.

3 data tables
Table 1

Separated cross sections at mean Q**2 of 1.60 GeV**2.

Table 2

Separated cross sections at mean Q**2 of 2.45 GeV**2.

Table 3

Extracted values of the charged pion form-factor. Errors are the statistical and experimental systematics combined in quadrature.


Differential cross section and photon beam asymmetry for the gamma(pol.) n --> K+ Sigma- reaction at e(gamma) = 1.5-GeV - 2.4-GeV.

Kohri, H. ; Ahn, D.S. ; Ahn, J.K. ; et al.
Phys.Rev.Lett. 97 (2006) 082003, 2006.
Inspire Record 709901 DOI 10.17182/hepdata.41825

Differential cross sections and photon beam asymmetries have been measured for the gamma n -> K+ Sigma- and gamma p -> K+ Sigma0 reactions separately using liquid deuterium and hydrogen targets with incident linearly polarized photon beams of Egamma=1.5-2.4 GeV at 0.6<cosTheta<1. The cross section ratio of sigma(K+Sigma-)/sigma(K+Sigma0), expected to be 2 on the basis of the isospin 1/2 exchange, is found to be close to 1. For the K+Sigma- reaction, large positive asymmetries are observed indicating the dominance of the K*-exchange. A large difference between the asymmetries for the K+Sigma- and K+Sigma0 reactions can not be explained by simple theoretical considerations.

4 data tables
Table 1

Differential cross section for GAMMA P --> K+ SIGMA0.. Errors are statistical only.

Table 2

Photon beam asymmetry for GAMMA N --> K+ SIGMA-.. Errors are statistical only.

Table 3

Photon beam asymmetry for GAMMA P --> K+ SIGMA0.. Errors are statistical only.

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The gamma(pol.) p --> K+ Lambda and gamma(pol.) p --> K+ Sigma0 reactions at forward angles with photon energies from 1.5-GeV to 2.4-GeV.

The LEPS collaboration Sumihama, M. ; Ahn, J.K. ; Akimune, H. ; et al.
Phys.Rev.C 73 (2006) 035214, 2006.
Inspire Record 701097 DOI 10.17182/hepdata.41824

Differential cross sections and photon beam asymmetries for the gamma p rightarrow K+ Lambda and gamma p rightarrow K+ Sigma0 reactions have been measured in the photon energy range from 1.5 GeV to 2.4 GeV and in the angular range from Theta_{cm} = 0 to 60 of the K+ scattering angle in the center of mass system at the SPring-8/LEPS facility. The photon beam asymmetries for both the reactions have been found to be positive and to increase with the photon energy. The measured differential cross sections agree with the data measured by the CLAS collaboration at cosTheta_{cm}<0.9 within the experimental uncertainties, but the discrepancy with the SAPHIR data for the K+Lambda reaction is large at cosTheta_{cm}>0.9. In the K+Lambda reaction, the resonance-like structure found in the CLAS and SAPHIR data at W=1.96 GeV is confirmed. The differential cross sections at forward angles suggest a strong K-exchange contribution in the t-channel for the K+Lambda reaction, but not for the K+Sigma0 reaction.

14 data tables
Table 1

Photon beam asymmetries for the two reactions as a function of CM angle for photon beam energy 1.55 GeV (W=1.947 GeV).

Table 2

Photon beam asymmetries for the two reactions as a function of CM angle for photon beam energy 1.65 GeV (W=1.994 GeV).

Table 3

Photon beam asymmetries for the two reactions as a function of CM angle for photon beam energy 1.75 GeV (W=2.041 GeV).

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eta' photoproduction on the proton for photon energies from 1.527-GeV to 2.227-GeV.

The CLAS collaboration Dugger, M. ; Ball, J.P. ; Collins, P. ; et al.
Phys.Rev.Lett. 96 (2006) 062001, 2006.
Inspire Record 700399 DOI 10.17182/hepdata.31553

Differential cross sections for the reaction gamma p -> eta-prime p have been measured with the CLAS spectrometer and a tagged photon beam with energies from 1.527 to 2.227 GeV. The results reported here possess much greater accuracy than previous measurements. Analyses of these data indicate for the first time the coupling of the etaprime N channel to both the S_11(1535) and P_11(1710) resonances, known to couple strongly to the eta N channel in photoproduction on the proton, and the importance of j=3/2 resonances in the process.

5 data tables
Table 1

Differential cross sections for ETAPRIME photoproduction on the proton at photon energies 1.527, 1.577 and 1.627 GeV. The errors shown are combined statistical and systematic.

Table 2

Differential cross sections for ETAPRIME photoproduction on the proton at photon energies 1.677, 1.728 and 1.779 GeV. The errors shown are combined statistical and systematic.

Table 3

Differential cross sections for ETAPRIME photoproduction on the proton at photon energies 1.829, 1.879 and 1.930 GeV. The errors shown are combined statistical and systematic.

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