Date

Elastic scattering of antiprotons on polarized protons at 1.73, 2.13, 2.37 and 2.97 GeV/c

Daum, C. ; Erné, F.C. ; Lagnaux, J.P. ; et al.
Nucl.Phys.B 6 (1968) 617-627, 1968.
Inspire Record 1392687 DOI 10.17182/hepdata.806

Differential cross section and polarization distributions are presented for elastic p p scattering at incident momenta of 1.73, 2.13, 2.37 and 2.97 GeV/ c . The data have been analysed in terms of a 5-parameter diffraction model. In terms of this model the difference in the shape of the differential cross sections for p p and pp elastic scattering is a result of the strong absorption in the p p system.

11 data tables

'1'. '2'. '3'. '4'.

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Measurement of Angular Asymmetries in the Decays B->K*l+l-

The BaBar collaboration Lees, J.P. ; Poireau, V. ; Tisserand, V. ; et al.
Phys.Rev.D 93 (2016) 052015, 2016.
Inspire Record 1391152 DOI 10.17182/hepdata.75484

We study the lepton forward-backward asymmetry AFB and the longitudinal K* polarization FL, as well as an observable P2 derived from them, in the rare decays B->K*l+l-, where l+l- is either e+e- or mu+mu-, using the full sample of 471 million BBbar events collected at the Upsilon(4S) resonance with the Babar detector at the PEP-II e+e- collider. We separately fit and report results for the B+->K*+l+l- and B0->K*0l+l- final states, as well as their combination B->K*l+l-, in five disjoint dilepton mass-squared bins. An angular analysis of B+->K*+l+l- decays is presented here for the first time.

3 data tables

$F_L$ angular fit results.

$A_{FB}$ angular fit results.

$P_2$ results with total uncertainties.


Beam asymmetry $\Sigma$ measurements on the $\pi^-$ photoproduction off neutrons

The Graal collaboration Mandaglio, G. ; Mammoliti, F. ; Manganaro, M. ; et al.
Phys.Rev.C 82 (2010) 045209, 2010.
Inspire Record 872319 DOI 10.17182/hepdata.63833

The $\Sigma$ beam asymmetry in the photoproduction of negative pions from quasi-free neutrons in a deuterium target was measured at Graal in the energy interval 700 - 1500 MeV and a wide angular range, using polarized and tagged photons. The results are compared with recent partial wave analyses.

11 data tables

The measured beam polarization asymmetry for photon energy 753 MeV.

The measured beam polarization asymmetry for photon energy 820 MeV.

The measured beam polarization asymmetry for photon energy 884 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

Axis error includes +- 18.6/18.6 contribution.

Axis error includes +- 18.6/18.6 contribution.

Axis error includes +- 18.6/18.6 contribution.

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Measurement of eta photoproduction on the proton from threshold to 1500-MeV

The GRAAL collaboration Bartalini, O. ; Bellini, V. ; Bocquet, J.P. ; et al.
Eur.Phys.J.A 33 (2007) 169-184, 2007.
Inspire Record 755415 DOI 10.17182/hepdata.51526

Beam asymmetry and differential cross section for the reaction gamma+p->eta+p were measured from production threshold to 1500 MeV photon laboratory energy. The two dominant neutral decay modes of the eta meson, eta->2g and eta->3pi0, were analyzed. The full set of measurements is in good agreement with previously published results. Our data were compared with three models. They all fit satisfactorily the results but their respective resonance contributions are quite different. The possible photoexcitation of a narrow state N(1670) was investigated and no evidence was found.

45 data tables

Measured beam asymmetry at photon energy 724 MeV as a function of the ETA centre of mass angle.

Measured beam asymmetry at photon energy 761 MeV as a function of the ETA centre of mass angle.

Measured beam asymmetry at photon energy 810 MeV as a function of the ETA centre of mass angle.

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Polarization of J / psi and psi(2S) mesons produced in p anti-p collisions at s**(1/2) = 1.96-TeV

The CDF collaboration Abulencia, A. ; Adelman, Jahred A. ; Affolder, T. ; et al.
Phys.Rev.Lett. 99 (2007) 132001, 2007.
Inspire Record 747876 DOI 10.17182/hepdata.42742

We have measured the polarizations of J/ψ and ψ(2S) mesons as functions of their transverse momentum pT when they are produced promptly in the rapidity range |y|<0.6 with pT≥5  GeV/c. The analysis is performed using a data sample with an integrated luminosity of about 800  pb−1 collected by the CDF II detector. For both vector mesons, we find that the polarizations become increasingly longitudinal as pT increases from 5 to 30  GeV/c. These results are compared to the predictions of nonrelativistic quantum chromodynamics and other contemporary models. The effective polarizations of J/ψ and ψ(2S) mesons from B-hadron decays are also reported.

2 data tables

Polarization parameter ALPHA for J/PSI production.

Polarization parameter ALPHA for PSI(2S) production.


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

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

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

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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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

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.

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.

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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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

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

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

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

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Measurement of pi0 photoproduction on the proton from 550-MeV to 1500-MeV at GRAAL

The GRAAL collaboration Bartalini, O. ; Bellini, V. ; Bocquet, J.P. ; et al.
Eur.Phys.J.A 26 (2005) 399-419, 2005.
Inspire Record 703671 DOI 10.17182/hepdata.11281

Neutral pion photoproduction has been measured from 550 to 1500 MeV with the GRAAL facility, located at the ESRF in Grenoble. Differential cross-section and beam asymmetry have been measured over a wi

81 data tables

Measured differential angular distribution for incident photon energy 555 Mev.

Measured differential angular distribution for incident photon energy 578 Mev.

Measured differential angular distribution for incident photon energy 597 Mev.

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