The cross section for the reaction 2H(γ, p)n has been measured at laboratory photon energies Eγ = 133−158 MeV and c.m. angles between 30° and 150°. The reaction was induced by a tagged bremsstrahlung photon beam incident on a liquid deuterium target. The uncertainty in the absolute cross sections is ⩽ 5%. There is now reasonable agreement between recent measurements in this energy region and the overall data set now defines the cross section sufficiently well to provide a test of current models of the reaction.
No description provided.
No description provided.
Nearly complete angular distributions of the two-body deuteron photodisintegration differential cross section have been measured using the CLAS detector and the tagged photon beam at JLab. The data cover photon energies between 0.5 and 3.0 GeV and center-of-mass proton scattering angles 10-160 degrees. The data show a persistent forward-backward angle asymmetry over the explored energy range, and are well-described by the non-perturbative Quark Gluon String Model.
Angular distributions of the photodisintegration cross section for angle between 10 and 50 degrees in the CM.
Angular distributions of the photodisintegration cross section for angle between 50 and 90 degrees in the CM.
Angular distributions of the photodisintegration cross section for angle between 90 and 130 degrees in the CM.
Measurements were performed for the photodisintegration cross section of the deuteron for photon energies from 1.6 to 2.8 GeV and center-of-mass angles from 37° to 90°. The measured energy dependence of the cross section at θc.m.=90° is in agreement with the constituent counting rules.
Statistical and systematic errors have been added in quadrature. Photon energy and angle (in deg) are in center-of-mass system.
The differential cross section for the reactions γd→pn, γd→π0d, and γd→pX has been measured by using a tagged photon beam in the energy range of dibaryon resonances. The most characteristic feature of the data for γd→pn is a forward nonpeaking angular distribution. This behavior is in complete disagreement with the existing predictions which take into account the dibaryon resonances. A phenomenological analysis is made by slightly modifying the model of the Tokyo group, but no satisfactory result is obtained. The data for γd→π0d at large angles show that the differential cross section decreases exponentially as a function of pion angle. A comparison is made with a Glauber model calculation. The result seems to be rather in favor of the existence of dibaryon resonances, but a clear conclusion is not possible because of a lack of more accurate data. In the process γd→pX, a broad peak due to quasifree pion production is observed, but the limitation of experimental sensitivity does not allow us to have a definite conclusion for the dibaryon resonance of mass 2.23 GeV conjectured by the Saclay group.
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No description provided.
FOR ANGLES >16 DEG THE OVERALL UNCERTAINTY IN ABSOLUTE NORMALIZATION IS ABOUT 10%.
The differential cross section for γd→pn has been measured in the energy range between 180 and 600 MeV at c.m. angles 15°, 30°, 42°, and 72°, by using tagged photons. The results, in particular at smaller angles, are in disagreement with theoretical calculations which take into account the effect of dibaryon resonances.
FIRST TABLE IS EXACT AVERAGE CM ANGLE AGAINST PHOTON ENERGY FOR THE SECOND TABLE.
FIRST TABLE IS EXACT AVERAGE CM ANGLE AGAINST PHOTON ENERGY FOR THE SECOND TABLE.
FIRST TABLE IS EXACT AVERAGE CM ANGLE AGAINST PHOTON ENERGY FOR THE SECOND TABLE.
The proton polarization in the γ d → pn reaction has been measured at a c.m. angle of 90° and photon energies between 350 and 700 MeV, using a carbon polarimeter. The magnitude of the polarization shows a sharp energy dependence with a peak of about −80% at around 500–550 MeV. This feature cannot be explained by conventional models and seems to indicate a new mechanism in the dibaryon system.
AROUND THETA OF 90 DEG.
Proton polarization in γd→pn has been measured at c.m. angle around 90° and photon energies from 325 to 725 MeV. The polarization increases sharply with the photon energy, reaching a high maximum of (-80±8)% around 500-550 MeV. Such a high polarization with a sharp energy dependence seems to indicate a new effect in the dibaryon system.
No description provided.
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ERRORS INCLUDE BY QUADRATIC ADDITION THE 5 PCT UNCERTAINTY IN THE CARBON ANALYSING POWER.
The proton polarization in deuteron photodisintegration has been measured at photon energies between 400 and 650 MeV at c.m. angles between 45° and 135°. To explain the polarization and differential cross-section data consistently, we have introduced dibaryon resonances and performed a partial-wave analysis at photon energies between 350 and 700 MeV. It has been shown that the existence of at least two dibaryon resonances is required in this energy range: one at ∼2380MeV with I ( J P ) = 0(3 + ) or 0(1 + ), and the other at ∼2260 MeV with I ( J P ) = 1(3 − ) or 1(2 − ).
No description provided.