A new accurate measurement of the tensor analyzing powers T20, T21, and T22 in deuteron photodisintegration has been performed. Wide-aperture nonmagnetic detectors allowed broad kinematic coverage in a single set up: E(gamma)=25 to 600 MeV, and theta(p)(cm)=24 degrees to 48 degrees and 70 degrees to 102 degrees . The new data provide a significant improvement over the few existing measurements. The angular dependency of the tensor asymmetries in deuteron photodisintegration is extracted for the first time.
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http://dx.doi.org/10.1103/PhysRevLett.98.182303 | DOI Listing |
Phys Rev Lett
April 2020
Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA.
We report a measurement of the spin polarization of the recoiling neutron in deuterium photodisintegration, utilizing a new large acceptance polarimeter within the Crystal Ball at MAMI. The measured photon energy range of 300-700 MeV provides the first measurement of recoil neutron polarization at photon energies where the quark substructure of the deuteron plays a role, thereby providing important new constraints on photodisintegration mechanisms. A very high neutron polarization in a narrow structure centered around E_{γ}∼570 MeV is observed, which is inconsistent with current theoretical predictions employing nucleon resonance degrees of freedom.
View Article and Find Full Text PDFPhys Rev Lett
June 2013
INFN, Sezione di Roma Tor Vergata, 00133 Rome, Italy.
We have measured cross sections for the γ(3)He → pd reaction at photon energies of 0.4-1.4 GeV and a center-of-mass angle of 90°.
View Article and Find Full Text PDFPhys Rev Lett
May 2007
Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia.
A new accurate measurement of the tensor analyzing powers T20, T21, and T22 in deuteron photodisintegration has been performed. Wide-aperture nonmagnetic detectors allowed broad kinematic coverage in a single set up: E(gamma)=25 to 600 MeV, and theta(p)(cm)=24 degrees to 48 degrees and 70 degrees to 102 degrees . The new data provide a significant improvement over the few existing measurements.
View Article and Find Full Text PDFPhys Rev Lett
May 2007
Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA.
We measured the angular dependence of the three recoil-proton polarization components in two-body photodisintegration of the deuteron at a photon energy of 2 GeV. These new data provide a benchmark for calculations based on quantum chromodynamics. Two of the five existing models have made predictions of polarization observables.
View Article and Find Full Text PDFPhys Rev Lett
January 2005
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, PO 13, 00044 Frascati, Italy.
We investigate the transition from the nucleon-meson to the quark-gluon description of the strong interaction using the photon energy dependence of the d(gamma,p)n differential cross section for photon energies above 0.5 GeV and center-of-mass proton angles between 30 degrees and 150 degrees. A possible signature for this transition is the onset of cross-section s(-11) scaling with the total energy squared, s, at some proton transverse momentum P(T).
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