Brooks, W.K.
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Measurement of the beam asymmetry $\Sigma$ for $\pi^0$ and $\eta$ photoproduction on the proton at $E_\gamma = 9$ GeV

The GlueX collaboration Al Ghoul, H. ; Anassontzis, E.G. ; Austregesilo, A. ; et al.
Phys.Rev.C 95 (2017) 042201, 2017.
Inspire Record 1511149 DOI 10.17182/hepdata.76745

We report measurements of the photon beam asymmetry $\Sigma$ for the reactions $\vec{\gamma}p\to p\pi^0$ and $\vec{\gamma}p\to p\eta $ from the GlueX experiment using a 9 GeV linearly-polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous $\pi^0$ measurements and are the first $\eta$ measurements in this energy regime. The results are compared with theoretical predictions based on $t$-channel, quasi-particle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models.

2 data tables match query
Table 1

Measurement of the beam asymmetry $\Sigma$ for $\pi^0$ photoproduction on the proton at $E_\gamma = 9$ GeV. The uncorrelated systematic errors (syst) are given in the table below along with a correlated normalization uncertainty (norm) of 3.6% due to the beam polarization.

Table 2

Measurement of the beam asymmetry $\Sigma$ for $\eta$ photoproduction on the proton at $E_\gamma = 9$ GeV. The uncorrelated systematic errors (syst) are given in the table below along with a correlated normalization uncertainty (norm) of 3.6% due to the beam polarization.


Measurement of beam asymmetry for $\pi^-\Delta^{++}$ photoproduction on the proton at $E_\gamma$=8.5 GeV

The GlueX collaboration Adhikari, S. ; Akondi, C.S. ; Ali, A. ; et al.
Phys.Rev.C 103 (2021) L022201, 2021.
Inspire Record 1817577 DOI 10.17182/hepdata.110112

We report a measurement of the $\pi^-$ photoproduction beam asymmetry for the reaction $\vec{\gamma} p \rightarrow \pi^- \Delta^{++}$ using data from the GlueX experiment in the photon beam energy range 8.2--8.8 GeV. The asymmetry $\Sigma$ is measured as a function of four-momentum transfer $t$ to the $\Delta^{++}$ and compared to phenomenological models. We find that $\Sigma$ varies as a function of $t$: negative at smaller values and positive at higher values of $|t|$. The reaction can be described theoretically by $t$-channel particle exchange requiring pseudoscalar, vector, and tensor intermediaries. In particular, this reaction requires charge exchange, allowing us to probe pion exchange and the significance of higher-order corrections to one-pion exchange at low momentum transfer. Constraining production mechanisms of conventional mesons may aid in the search for and study of unconventional mesons. This is the first measurement of the process at this energy.

1 data table match query
Table 1

Beam asymmetry $\Sigma$ vs. $|t|$ compared to theoretical predictions. The uncertainty on $|t|$ is the rms of values in the $\Delta^{++}$ signal region. The uncertainties on $\Sigma$ are statistical and systematic (uncorrelated across t bins), respectively. There is an additional fully correlated systematic uncertainty of 1.5% on the magnitude of $\Sigma$.


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 match query
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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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 match query
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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Analyzing powers in p(pol.) p --> p n pi+ and determination of pion S and P wave amplitudes near threshold.

Daehnick, W.W ; Flammang, R.W ; Dytman, S.A ; et al.
Phys.Lett.B 423 (1998) 213-218, 1998.
Inspire Record 471256 DOI 10.17182/hepdata.28208

Analyzing powers were measured and used to quantify the observation that s -wave processes dominate near threshold. Values of A y ( θ π , φ π =0°) are presented for η values of 0.22, 0.42 and 0.50. Maximum analyzing powers A N 0 are equal to −0.13, −0.24, and −0.28, respectively. A partial wave analysis, made possible by the new analyzing powers and available cross sections, indicates that the s -wave contribution to the cross section constitutes about 91% of the total cross section at η =0.22, or 300 MeV. It decreases to about 75% for η =0.5.

1 data table match query
Table 1

Polarized beam.


Beam Asymmetry $\mathbf{\Sigma}$ for the Photoproduction of $\mathbf{\eta}$ and $\mathbf{\eta^{\prime}}$ Mesons at $\mathbf{E_{\gamma}=8.8}$GeV

The GlueX collaboration Adhikari, S. ; Ali, A. ; Amaryan, M. ; et al.
Phys.Rev.C 100 (2019) 052201, 2019.
Inspire Record 1749712 DOI 10.17182/hepdata.110166

We report on the measurement of the beam asymmetry $\Sigma$ for the reactions $\vec{\gamma}p\rightarrow p\eta$ and $\vec{\gamma}p \rightarrow p\eta^{\prime}$ from the GlueX experiment, using an 8.2--8.8 GeV linearly polarized tagged photon beam incident on a liquid hydrogen target in Hall D at Jefferson Lab. These measurements are made as a function of momentum transfer $-t$, with significantly higher statistical precision than our earlier $\eta$ measurements, and are the first measurements of $\eta^{\prime}$ in this energy range. We compare the results to theoretical predictions based on $t$--channel quasi-particle exchange. We also compare the ratio of $\Sigma_{\eta}$ to $\Sigma_{\eta^{\prime}}$ to these models, as this ratio is predicted to be sensitive to the amount of $s\bar{s}$ exchange in the production. We find that photoproduction of both $\eta$ and $\eta^{\prime}$ is dominated by natural parity exchange with little dependence on $-t$.

3 data tables match query
Eta Beam Asymmetry

Values and errors for the photon beam asymmetry $\Sigma_{\eta}$ for the reaction $\gamma p \rightarrow \eta p$ with $\eta\rightarrow\gamma\gamma$. For the binning in $t$, we report the range of the data, the event-weighted mean of all $t$ values, and the RMS of that distribution. For $\Sigma_{\eta}$, we report the value, statistical error, and systematic error. The total error is the sum of the previous two in quadrature. Not reported here is the $2.1\%$ relative uncertainty due to the determination of the polarization of the photon beam.

EtaPrime Beam Asymmetry

Values and errors for the photon beam asymmetry $\Sigma_{\eta\prime}$ for the reaction $\gamma p \rightarrow \eta^{\prime} p$ with $\eta^{\prime}\rightarrow \eta\pi^{+}\pi^{-}$ and the $\eta\rightarrow\gamma\gamma$. For the binning in $t$, we report the range of the data, the event-weighted mean of all $t$ values, and the RMS of that distribution. For $\Sigma_{\eta\prime}$, we report the value, statistical error, and systematic error. The total error is the sum of the previous two in quadrature. Not reported here is the $2.1\%$ relative uncertainty due to the determination of the polarization of the photon beam.

Beam Asymmetry Ratio

Values and errors for the ratio of photon beam asymmetries $\Sigma_{\eta\prime}/\Sigma_{\eta}$ for the reported reactions. To form the ratio, the $\eta$ analysis is done with the same binning in $t$ as the $\eta^\prime$ analysis, and for each bin we report the range of the data, the event-weighted mean of all $t$ values, and the RMS of that distribution. For $\Sigma_{\eta\prime}/\Sigma_{\eta}$, we report the value, statistical error, and systematic error. The total error is the sum of the previous two in quadrature.}


Measurement of the Photon Beam Asymmetry in $\vec{\gamma} p\to K^+\Sigma^0$ at $E_{\gamma} = 8.5$ GeV

The GlueX collaboration Adhikari, S. ; Ali, A. ; Amaryan, M. ; et al.
Phys.Rev.C 101 (2020) 065206, 2020.
Inspire Record 1785913 DOI 10.17182/hepdata.110167

We report measurements of the photon beam asymmetry $\Sigma$ for the reaction $\vec{\gamma} p\to K^+\Sigma^0$(1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected using a linearly polarized photon beam in the energy range of 8.2-8.8 GeV incident on a liquid hydrogen target. The beam asymmetry $\Sigma$ was measured as a function of the Mandelstam variable $t$, and a single value of $\Sigma$ was extracted for events produced in the $u$-channel. These are the first exclusive measurements of the photon beam asymmetry $\Sigma$ for the reaction in this energy range. For the $t$-channel, the measured beam asymmetry is close to unity over the $t$-range studied, $-t=(0.1-1.4)~$(GeV/$c$)$^{2}$, with an average value of $\Sigma = 1.00\pm 0.05$. This agrees with theoretical models that describe the reaction via the natural-parity exchange of the $K^{*}$(892) Regge trajectory. A value of $\Sigma = 0.41 \pm 0.09$ is obtained for the $u$-channel integrated up to $-u=2.0$~(GeV/$c$)$^{2}$.

2 data tables match query
K+ Sigma Beam Asymmetry t-channel

Beam asymmetry $\Sigma$ for the low $-t$ region where the horizontal error bars indicate the rms widths of the $t$ bin. The uncertainties on $\Sigma$ are statistical and systematic (uncorrelated across t bins), respectively. There is an additional fully correlated systematic uncertainty of 2.1% on the magnitude of $\Sigma$.

K+ Sigma Beam Asymmetry u-channel

Average beam asymmetry $\Sigma$ for the low $-u$ region where the uncertainty on $\Sigma$ is the statistical and systematic (uncorrelated across t bins), respectively. There is an additional fully correlated systematic uncertainty of 2.1% on the magnitude of $\Sigma$.


Proton proton bremsstrahlung at 280-MeV

Michaelian, K. ; Kitching, P. ; Hutcheon, D.A. ; et al.
Phys.Rev.D 41 (1990) 2689-2704, 1990.
Inspire Record 304884 DOI 10.17182/hepdata.23001

A proton-proton bremsstrahlung experiment has been carried out at TRIUMF using a 280-MeV polarized proton beam impinging on a liquid-hydrogen target. All three outgoing particles were detected: the higher-energy proton in a magnetic spectrometer, the lower-energy proton with plastic scintillators, and the photon in lead-glass Cherenkov detectors. The experiment shows the first unambiguous evidence for off-shell effects in the free nucleon-nucleon interaction, in that the analyzing powers disagree strongly with the predictions of the soft-photon approximation (which incorporates only on-shell information) but are consistent with the results of calculations using the Bonn and Paris potentials.

8 data tables match query
Table 1

Estimated scale uncertainty is 1.5 pct.

Table 2

Estimated scale uncertainty is 1.5 pct.

Table 3

Estimated scale uncertainty is 1.5 pct.

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Xi (1320) and Xi (1530) Production in $K^- p$ Interactions at 4.2-{GeV}/$c$

The Amsterdam-CERN-Nijmegen-Oxford collaboration Mazzucato, M. ; Pennino, D. ; Aguilar-Benitez, M. ; et al.
Nucl.Phys.B 178 (1981) 1-30, 1981.
Inspire Record 153470 DOI 10.17182/hepdata.34384

The reactions K − p → Ξ 0 − (1320) K 0 + , Ξ − (1320) K + (890), Ξ 0 − (1530) K 0 − and Ξ 0 − (1530) K 0 + (890) are studied at 4.2 GeV/ c incident momentum. The data come from a high-statistics bubble chamber experiment with a sensitivity of ∼ 133 events/ μ b. Total anddifferential cross sections are presented. The results are compared to the SU(3)-related processes K + p → pK + and K + p → pK + (890) in the backward hemisphere. In the forward hemisphere “forbidden” peaks are observed and current ideas about them are discussed.

16 data tables match query
Table 1

FULLY CORRECTED FOR ALL CUTS AND UNSEEN DECAY MODES.

Table 2

TOTAL, FORWARD AND BACKWARD CROSS SECTIONS. FULLY CORRECTED FOR CUTS, K0 AND LAMBDA UNSEEN DECAY MODES AND OTHER K*(892) AND XI(1530P13) DECAYS. IN 3-BODY FINAL STATES, THETA REFERS TO THE PI-K SYSTEM.

Table 3

No description provided.

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Elastic Scattering of 600-MeV Protons from H, D, He-3, and He-4

Boschitz, E.T. ; Roberts, W.K. ; Vincent, J.S. ; et al.
Phys.Rev.C 6 (1972) 457-466, 1972.
Inspire Record 79822 DOI 10.17182/hepdata.25567

The elastic scattering of 600-MeV protons from light nuclei has been studied at the National Aeronautics Space Administration Space Radiation Effects Laboratory (SREL) synchrocyclotron. Differential cross sections have been obtained for the scattering of protons from hydrogen, deuterium, helium-3, and helium-4. Polarization was measured for deuterium and He4 nuclei. The p−p cross-section data are in excellent agreement with the predictions from the Livermore phase shifts. Small-angle p−D, p−He3 elastic scattering data are compared with calculations based on the multiple-scattering theories of Watson and Glauber.

6 data tables match query
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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