We present data on the inclusive scattering of polarized electrons from a polarized 3He target at energies from 0.862 to 5.06 GeV, obtained at a scattering angle of 15.5 degrees. Our data include measurements from the quasielastic peak, through the nucleon resonance region, and beyond, and were used to determine the virtual photon cross-section difference sigma(1/2)-sigma(3/2). We extract the extended Gerasimov-Drell-Hearn integral for the neutron in the range of four-momentum transfer squared Q2 of 0.1-0.9 GeV2.
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http://dx.doi.org/10.1103/PhysRevLett.89.242301 | DOI Listing |
Phys Rev Lett
February 2018
Institut für Kernphysik & Cluster of Excellence PRISMA, Johannes Gutenberg-Universität Mainz, D-55128 Mainz, Germany.
The theoretical uncertainty of (g-2)_{μ} is currently dominated by hadronic contributions. In order to express those in terms of directly measurable quantities, we consider a sum rule relating g-2 to an integral of a photoabsorption cross section. The sum rule, attributed to Schwinger, can be viewed as a combination of two older sum rules: Gerasimov-Drell-Hearn and Burkhardt-Cottingham.
View Article and Find Full Text PDFPhys Rev Lett
May 2009
Department of Physics, University of Virginia, Charlottesville, Virginia 22901, USA.
We report new measurements of inclusive pi production from frozen-spin HD for polarized photon beams covering the Delta(1232) resonance. These provide data simultaneously on both H and D with nearly complete angular distributions of the spin-difference cross sections entering the Gerasimov-Drell-Hearn (GDH) sum rule. Recent results from Mainz and Bonn exceed the GDH prediction for the proton by 22 microb, suggesting as yet unmeasured high-energy components.
View Article and Find Full Text PDFPhys Rev Lett
November 2004
Institut für Kernphysik, Johannes Gutenberg-Universität, D-55099 Mainz, Germany.
An explicit evaluation of the spin asymmetry of the deuteron and the associated Gerasimov-Drell-Hearn sum rule is presented which includes photodisintegration, and single and double pion and eta production as well. Photodisintegration is treated with a realistic retarded potential and a corresponding meson exchange current. For single pion and eta production the elementary operator from MAID is employed, whereas for double pion production, an effective Lagrangian approach is used.
View Article and Find Full Text PDFPhys Rev Lett
July 2004
Physikalisches Institut, Universität Bonn, D-53115 Bonn, Germany.
For the first time we checked the fundamental Gerasimov-Drell-Hearn (GDH) sum rule for the proton experimentally in the photon energy range from 0.2-2.9 GeV with the tagged photon facilities at MAMI (Mainz) and ELSA (Bonn).
View Article and Find Full Text PDFPhys Rev Lett
December 2002
Istituto Nazionale di Fiscica Nucleare, Sezione Sanità, 00161 Roma, Italy.
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