The $\Sigma$ beam asymmetry in $\eta^{\prime}$ photoproduction off the proton was measured at the GrAAL polarized photon beam with incoming photon energies of 1.461 and 1.480 GeV. For both energies ...the asymmetry as a function of the meson emission angle shows a clear structure, more pronounced at the lowest one, with a change of sign around 90$^o$. The results are compared to the existing theories that fail to account for the data.
Paleodemography: Expectancy and false hope Bocquet-Appel, J. P.; Masset, C.
American journal of physical anthropology,
April 1996, Letnik:
99, Številka:
4
Journal Article
After 40kyr bp, the distribution of archaeological sites shows that the occupation of the western-European peninsula, at the north of the Alpine arc, has the appearance of nodes of concentration, ...separated by vast zones which are either empty or with a negligible population density. The populational kinetics of the hunter–gatherers in this vast area is characterized by the permanence of a refuge zone located in northern Aquitaine. The leptokurtic aspect of the density distributions of sites observed from the Aurignacian to the Glacial Maximum but not at the Magdalenian suggest occasional long distance movement such as raids or opportunistic expeditions. During the Glacial Maximum, the response to the cold is marked by the complete abandonment of the northern peripheral zone, a contraction of the population mainly on the first peripheral zone surrounding the refuge zone, but without geographical change of position of the refuge zone. An optimistic estimate of the meta-population size of hunter–gatherers, which takes into account the change of area size due to the sea level variation, goes from the Aurignacian, 4000, to the Glacial Maximum 8000. During the Magdalenian a demographic explosion occurred with 40,000 individuals.
The differential cross section for the reaction p(γ,ηp) has been measured from threshold to 1100 MeV photon laboratory energy. For the first time, the region of the S11(1535) resonance is fully ...covered in a photoproduction experiment and will allow a precise extraction of its parameters at the photon point. These high precision data together with the already measured beam asymmetry data will provide stringent constraints on the extraction of new couplings of baryon resonances to the η meson.
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 ...wide angular range. These high-precision data improve significantly the database for the beam asymmetry in the second and third resonance regions covering for the first time the energy domain 1100-1500 MeV. New partial-wave analyses including these data are presented for which the beam asymmetry brings crucial constraints.
Static and dynamic polarization of HD Bassan, M.; Bouchigny, S.; Commeaux, C. ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,
06/2004, Letnik:
526, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
The static polarization of HD samples has been achieved using “brute force”, for HD samples purified by double distillation. Proton polarization in excess of 60% and deuteron vector polarization ...higher than 14% have been reached. It has been demonstrated that the ageing technique allows to get relaxation times at
1.5
K
and
1
T
larger than a week. It is advocated that the conventional dynamic polarization of HD should be feasible for the proton and the deuteron contained in the HD molecule. This would simplify considerably the machinery presently necessary to perform nuclear physics experiments with HD targets polarized by the static method.
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