B. Norum
University of Virginia, Physics, Faculty Member
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The first beam-target double-polarization data taken with a new polarized target using HD in the solid phase are reported here. Preliminary pion photo-production results on the double-polarization observables G and E are shown for the... more
The first beam-target double-polarization data taken with a new polarized target using HD in the solid phase are reported here. Preliminary pion photo-production results on the double-polarization observables G and E are shown for the proton. The latter determines the size of the GDH observable sigma1/2 - sigma3/2. Preliminary results for this quantity are also given.
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Frozen-spin HD targets have been used to measure beam-target double-polarization observables in pion photo-production at the LEGS (Laser Electron Gamma Source) facility. The HD targets are pure; the only unpolarizable nucleons associated... more
Frozen-spin HD targets have been used to measure beam-target double-polarization observables in pion photo-production at the LEGS (Laser Electron Gamma Source) facility. The HD targets are pure; the only unpolarizable nucleons associated with the target cell are sampled in empty-cell measurements and subtracted in the conventional way, resulting in exceptionally clean spectra. HD gas is isotopically purified by distillation and
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Supported by the National Science Foundation and Indiana University
Research Interests: Physics, Nuclear Physics, Energy, Isotope, Oxygen, and 7 moreInelastic, Scattering, Proton, Elastic, Beryllium, Intermediate, and Scatter
It is clear that new experimental data is needed to compare with recent Lorentz Integral Transform calculations of the photodisintegration cross sections of the lithium isotopes. We describe a recent measurement on these isotopes... more
It is clear that new experimental data is needed to compare with recent Lorentz Integral Transform calculations of the photodisintegration cross sections of the lithium isotopes. We describe a recent measurement on these isotopes performed with the monochromatic, polarized photon beam at the High Intensity Gamma-Ray Source (HIGS) at Duke University in Durham, NC, USA. The Blowfish Neutron Detector Array, a segmented neutron detector array with good angular resolution that covers .5ex1 -.1em/ -.15em.25ex4 of 4pi steradians, was used to detect photoneutrons. Clear separation of various reaction channels is possible which allows detector efficiencies to be accurately modeled using a GEANT4 simulation. Several methods for obtaining the incident photon flux are available so precision cross sections between 8 and 35 MeV can be obtained. )
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We propose to make a high precision measurement of the threshold contribution to the Deuteron extended GDH sum over the momentum transfer range 0.015 < Q < 0.2 GeV. We plan to use JLab’s polarized electron beam with 100–150 nA... more
We propose to make a high precision measurement of the threshold contribution to the Deuteron extended GDH sum over the momentum transfer range 0.015 < Q < 0.2 GeV. We plan to use JLab’s polarized electron beam with 100–150 nA current and two incident energies of 600 and 1200 MeV. The University of Virginia solid polarized ND3 target will be utilized along with the Hall C High Momentum Spectrometer in standard configuration at 12.5◦ to 20.5◦ . The HMS excitation energy resolution will be approximately 1 MeV, providing sufficient separation from the elastic scattering process. This experiment will reduce the systematic uncertainty of the Deuteron threshold contribution to the extended GDH sum measurement of PR05-111 [1], and will also provide very precise vector asymmetries and cross sections in the quasielastic region. We request 42 hours to perform this measurement. 1 Theoretical Background 1.1 The GDH Sum Rule The Gerasimov-Drell-Hearn (GDH) sum rule for real photon absorpti...
We propose to perform a high precision measurement of the GerasimovDrell-Hearn integral in the 0.015<Q<0.4 GeV range, using the Hall A High Resolution Spectrometers combined with the septum magnets. Such data will provide a clean... more
We propose to perform a high precision measurement of the GerasimovDrell-Hearn integral in the 0.015<Q<0.4 GeV range, using the Hall A High Resolution Spectrometers combined with the septum magnets. Such data will provide a clean benchmark measurement for Chiral Perturbation Theory and will help to disentangle theoretical issues related to χPT calculations. The combination of these proton data with neutron data will also be extremely valuable. Finally such a measurement will complete the proton data already taken at JLAB and in other high energy facilities in such a way that we will have measurements of the GDH integral on the proton in the full Q range, i.e from the photon point to well into the DIS domain. We plan to use the UVa polarized NH3 target. With 20 days of beam time we can reach a ±2% (stat) ±8% (syst) on the integral and ±6 % (stat) ±8% (syst) on the spin structure function g1.
M. Posik, ∗ D. Flay, D. S. Parno, 3 K. Allada, W. Armstrong, T. Averett, F. Benmokhtar, 2 W. Bertozzi, A. Camsonne, M. Canan, G.D. Cates, C. Chen, J.-P. Chen, S. Choi, E. Chudakov, F. Cusanno, 14 M. M. Dalton, W. Deconinck, C.W. de Jager,... more
M. Posik, ∗ D. Flay, D. S. Parno, 3 K. Allada, W. Armstrong, T. Averett, F. Benmokhtar, 2 W. Bertozzi, A. Camsonne, M. Canan, G.D. Cates, C. Chen, J.-P. Chen, S. Choi, E. Chudakov, F. Cusanno, 14 M. M. Dalton, W. Deconinck, C.W. de Jager, X. Deng, A. Deur, C. Dutta, L. El Fassi, 15 G. B. Franklin, M. Friend, H. Gao, F. Garibaldi, S. Gilad, R. Gilman, 15 O. Glamazdin, S. Golge, J. Gomez, L. Guo, O. Hansen, D. W. Higinbotham, T. Holmstrom, J. Huang, C. Hyde, 20 H. F. Ibrahim, X. Jiang, 18 G. Jin, J. Katich, A. Kelleher, A. Kolarkar, W. Korsch, G. Kumbartzki, J.J. LeRose, R. Lindgren, N. Liyanage, E. Long, A. Lukhanin, V. Mamyan, D. McNulty, Z.-E. Meziani, † R. Michaels, M. Mihovilovič, B. Moffit, 8 N. Muangma, S. Nanda, A. Narayan, V. Nelyubin, B. Norum, Nuruzzaman, Y. Oh, J. C. Peng, X. Qian, 27 Y. Qiang, 8 A. Rakhman, S. Riordan, 29 A. Saha, ‡ B. Sawatzky, 8 M. H. Shabestari, A. Shahinyan, S. Širca, 24 P. Solvignon, 8 R. Subedi, V. Sulkosky, 8 W. A. Tobias, W. Troth, D. Wang, Y. Wan...
We propose to test the time reversal invariance properties of the electromagnetic interaction, improving the precision of current measurements by a factor of 100 to 250, in 60 days of running. The measurement can be done using TJNAF's... more
We propose to test the time reversal invariance properties of the electromagnetic interaction, improving the precision of current measurements by a factor of 100 to 250, in 60 days of running. The measurement can be done using TJNAF's electron beam, a solid polarized
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Abstract: Neutral pion photoproduction from a liquid deuterium target was measured in the energy region near 300 MeV at the LEGS facility of Brookhaven National Laboratory. The inclusive cross sections from deuterium are in agreement with... more
Abstract: Neutral pion photoproduction from a liquid deuterium target was measured in the energy region near 300 MeV at the LEGS facility of Brookhaven National Laboratory. The inclusive cross sections from deuterium are in agreement with measurments from Mainz, ...
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We report preliminary results of pi photo-production using polarized gamma beams and a polarized HD target. Four observables can be extracted simultaneously from the data, the cross section, the beam asymmetry Sigma, and the... more
We report preliminary results of pi photo-production using polarized gamma beams and a polarized HD target. Four observables can be extracted simultaneously from the data, the cross section, the beam asymmetry Sigma, and the double-polarization observables G and E. The latter determines the GDH sum rule integral.
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Cross sections and asymmetries have been measured for the ^16O(gamma,pp), and ^16O(gamma,pn) reactions with polarized photons with energies from 205 to 315 MeV using the LEGS facility at Brookhaven National Laboratory. Protons and... more
Cross sections and asymmetries have been measured for the ^16O(gamma,pp), and ^16O(gamma,pn) reactions with polarized photons with energies from 205 to 315 MeV using the LEGS facility at Brookhaven National Laboratory. Protons and neutrons were detected and identified in an Delta E-E array of plastic (Bicron 408) and CsI scintillators located 100 cm from a water target covering a broad
Research Interests: Physics and Cross Section
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Research Interests: Physics, Atomic Physics, Inelastic Neutron Scattering, Physical sciences, Density dependence, and 11 moreNuclear Reactions, Elastic Scattering, Excited states, Hartree fock method, Cross Section, Charge Density, Energy Levels, Momentum Transfer, Electron scattering, Form Factor, and Charged Particles
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The differential cross section for the reaction 15N(gamma,pi-)15Ogs has been measured at a photon energy of 220 MeV. We find a discrepancy between our data and a calculation based on the distorted wave impulse approximation which uses... more
The differential cross section for the reaction 15N(gamma,pi-)15Ogs has been measured at a photon energy of 220 MeV. We find a discrepancy between our data and a calculation based on the distorted wave impulse approximation which uses phenomenological 1p-shell wave functions. A second calculation, in which higher-shell configurations are included in the wave functions, fails to correct the discrepancy and
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... integrand MA Blackston,* MW Ahmed, BA Perdue, and HR Weller Department of Physics, Duke University, Durham, North Carolina 27708, USA and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA B ...
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Form-factor measurements in the momentum-transfer range 0.6&amp;amp;amp;amp;amp;amp;lt;=q&amp;amp;amp;amp;amp;amp;lt;=2.7 fm-1 are presented for the 1- levels in 18O at 4.46, 6.20, 7.62, and 8.04 MeV, the 3- levels at 5.10, 6.40,... more
Form-factor measurements in the momentum-transfer range 0.6&amp;amp;amp;amp;amp;amp;lt;=q&amp;amp;amp;amp;amp;amp;lt;=2.7 fm-1 are presented for the 1- levels in 18O at 4.46, 6.20, 7.62, and 8.04 MeV, the 3- levels at 5.10, 6.40, and 8.29 MeV, and the 5- levels at 7.86 and 8.13 MeV. These are the first measurements of the 5- states by inelastic scattering and the first electron-scattering measurements of the
Research Interests: Physics, Atomic Physics, Medicine, OMEGA, Inelastic Neutron Scattering, and 14 moreNuclear Structure, Oscillations, Physical, Nuclear Reactions, Cross Section, Scattering, Quantum Harmonic Oscillator, Experimental Data, Structural model, Momentum Transfer, Electron scattering, Form Factor, Charged Particles, and Polynomial Time
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Recent experimental data on nucleon spin structure at low to intermediate momentum transfers has provided valuable new information in the confinement regime, and shed light on the transition from confinement to asymptotic freedom. New... more
Recent experimental data on nucleon spin structure at low to intermediate momentum transfers has provided valuable new information in the confinement regime, and shed light on the transition from confinement to asymptotic freedom. New insight has been gained by exploring moments of the spin structure functions and their corresponding sum rules. At low Q 2, Chiral Perturbation Theory (χPT)
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Experimental cross sections for the $^4He(e,e'p)X$ reaction up to a missing momentum of 0.632 GeV/$c$ at $x_B=1.24$ and $Q^2$=2(GeV/$c$)$^2$ are reported. The data are compared to Relativistic Distorted Wave Impulse... more
Experimental cross sections for the $^4He(e,e'p)X$ reaction up to a missing momentum of 0.632 GeV/$c$ at $x_B=1.24$ and $Q^2$=2(GeV/$c$)$^2$ are reported. The data are compared to Relativistic Distorted Wave Impulse Approximation(RDWIA) calculations for $^4He(e,e'p)^3H$ channel. Significantly more events in the triton mass region are measured for $p_{m}$$>$0.45 GeV/$c$ than are predicted by the theoretical model, suggesting that the effects of initial-state multi-nucleon correlations are stronger than expected by the RDWIA model.
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... A VERY HIGH RESOLUTION IVIWPC SYSTEM FOR INCLINED TRACKS"0 W. BERTOZZI, MV HYNES, CP SARGENT, C. CRESWELL, PC DUNN, A. KIRSCH, M. LEITCH, B ... The timing measurer-ients are accomplished for the entire VDC with a single... more
... A VERY HIGH RESOLUTION IVIWPC SYSTEM FOR INCLINED TRACKS"0 W. BERTOZZI, MV HYNES, CP SARGENT, C. CRESWELL, PC DUNN, A. KIRSCH, M. LEITCH, B ... The timing measurer-ients are accomplished for the entire VDC with a single multiple-stop tine digitizer. ...
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The charge and magnetic form factors, F_{C} and F_{M}, respectively, of ^{3}He are extracted in the kinematic range 25 fm^{-2}≤Q^{2}≤61 fm^{-2} from elastic electron scattering by detecting ^{3}He recoil nuclei and scattered electrons... more
The charge and magnetic form factors, F_{C} and F_{M}, respectively, of ^{3}He are extracted in the kinematic range 25 fm^{-2}≤Q^{2}≤61 fm^{-2} from elastic electron scattering by detecting ^{3}He recoil nuclei and scattered electrons in coincidence with the two High Resolution Spectrometers of the Hall A Facility at Jefferson Lab. The measurements find evidence for the existence of a second diffraction minimum for the magnetic form factor at Q^{2}=49.3 fm^{-2} and for the charge form factor at Q^{2}=62.0 fm^{-2}. Both minima are predicted to exist in the Q^{2} range accessible by this Jefferson Lab experiment. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the three-body nuclear problem.
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Measurement of “pretzelosity” asymmetry of charged pion production in semi-inclusive deep inelastic scattering on a polarized <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML"><mmultiscripts><mi mathvariant="normal">He</mi><mprescripts></mprescripts><none></none><m
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The electromagnetic form factors have been measured for the lowest two T=32 states in 9Be at 14.393 and 16.976 MeV, the positive-parity state at 17.490 MeV, and a level of previously unknown Jpi at 16.671 MeV. The range of effective... more
The electromagnetic form factors have been measured for the lowest two T=32 states in 9Be at 14.393 and 16.976 MeV, the positive-parity state at 17.490 MeV, and a level of previously unknown Jpi at 16.671 MeV. The range of effective momentum transfer is 0.9&amp;lt;=qe&amp;lt;=2.5 fm-1. The data for the T=32 states show considerable deviation from the results of intermediate-coupling shell-model