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A new measurement of the rare, doubly radiative decay eta->pi^0 gamma gamma was conducted with the Crystal Ball and TAPS multiphoton spectrometers together with the photon tagging facility at the Mainz Microtron MAMI. New data on the dependence of the partial decay width, Gamma(eta->pi^0 gamma gamma), on the two-photon invariant mass squared, m^2(gamma gamma), as well as a new, more precise value for the decay width, Gamma(eta->pi^0 gamma gamma) = (0.33+/-0.03_tot) eV, are based on analysis of 1.2 x 10^3 eta->pi^0 gamma gamma decays from a total of 6 x 10^7 eta mesons produced in the gamma p -> eta p reaction. The present results for dGamma(eta->pi^0 gamma gamma)/dm^2(gamma gamma) are in good agreement with previous measurements and recent theoretical calculations for this dependence.

1 data table

Table 1

D(WIDTH(ETA --> PI0 GAMMA GAMMA))/DM**2(GAMMA GAMMA) obtained from the data of 2007 and 2009 and their average. The error on the average is the total error.

High-precision Measurements of piP Elastic Differential Cross Sections in the Second Resonance Region

The EPECUR collaboration Alekseev, I.G. ; Andreev, V.A. ; Bordyuzhin, I.G. ; et al.

Phys.Rev.C 91 (2015) 025205, 2015.

Inspire Record 1323450 DOI 10.17182/hepdata.67659

Cross sections for pi+-p elastic scattering have been measured to high precision, for beam momenta between 800 and 1240 MeV/c, by the EPECUR Collaboration, using the ITEP proton synchrotron. The data precision allows comparisons of the existing partial-wave analyses (PWA) on a level not possible previously. These comparisons imply that updated PWA are required.

249 data tables

Table 1

Differential cross section of elastic $\pi^+$p-scattering at P= 800.25 MeV/c. Errors shown are statistical only.

Table 2

Differential cross section of elastic $\pi^+$p-scattering at P= 803.75 MeV/c. Errors shown are statistical only.

Table 3

Differential cross section of elastic $\pi^+$p-scattering at P= 807.25 MeV/c. Errors shown are statistical only.

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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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ASYMMETRY MEASUREMENTS IN PION PHOTOPRODUCTION BY POLARIZED PHOTONS IN THE ENERGY RANGE FROM 250-MeV TO 600-MeV

Measurement of Asymmetry of Photoproduction of Positive Pions on Protons by Linearly Polarized Photons in 250-MeV-500-MeV Energy Range

Angular distributions of the asymmetry of the gamma p ---> p pi0 reaction with the gamma-quanta energies of 400, 450, 500, 550, 650 mev

Angular dependence of the asymmetry of the cross section for the reaction $\gamma$p $\rightarrow$ $\Delta^{++}\pi^{-}$ at a photon energy 650 MeV

Asymmetry of the cross section of gamma d ---> pi0 d reaction at photon energy of 350 mev

Single Photoproduction of Negative Pions from Neutrons by Linearly Polarized Photons in the Region of the First Pion-Nucleon Resonance

Investigation of (gamma, p) reaction on the li-7 nucleus by means of a beam of quasimonochromatic and polarized photons

rivet Analysis
A new measurement of the rare decay eta -> pi^0 gamma gamma with the Crystal Ball/TAPS detectors at the Mainz Microtron

High-precision Measurements of piP Elastic Differential Cross Sections in the Second Resonance Region

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