Calvin R. Howell
Professor of Physics
Professor Howell’s research is in the area of experimental nuclear physics with emphasis on the quantum chromodynamics (QCD) description of low-energy nuclear phenomena, including structure properties of nucleons and nuclei and reaction dynamics in few-nucleon systems. The macroscopic properties of nucleon structure and the residual strong nuclear force between neutrons and protons in nuclei emerge from QCD at distances where the color interactions between quarks and gluons are strong. However, the details of the mechanisms that generate the strong nuclear force are not well understood. Effective field theories (EFT) and Lattice QCD calculations provide theoretical frames that connect low-energy nuclear phenomena to QCD. Professor Howell and collaborators are conducting experiments on few-nucleon systems that test predictions of ab-initio theory calculations for the purpose of providing insight about the QCD descriptions of low-energy nucleon interactions and structure. His current projects include measurements of the electromagnetic and spin-dependent structure properties of nucleons via Compton scattering on the proton and few-nucleon systems and studies of two- and three-nucleon interactions using few-nucleon reactions induced by photons and neutrons. In the coming years, a focus will be on investigating the neutron-neutron interaction in reactions and inside nuclei. In addition, his work includes applications of nuclear physics to national nuclear security, medical isotope production, and plant biology. Most of his research is carried out at the High Intensity Gamma-ray Source and the tandem laboratory at TUNL.
Crawford, B. E., et al. “Calculations of neutron spectra after neutron-neutron scattering.” Journal of Physics G: Nuclear and Particle Physics, vol. 30, no. 9, Sept. 2004, pp. 1269–85. Scopus, doi:10.1088/0954-3899/30/9/024. Full Text
Floyd, C. E., et al. “Neutron stimulated emission computed tomography of stable isotopes.” Proceedings of Spie the International Society for Optical Engineering, vol. 5368, no. 1, July 2004, pp. 248–54. Scopus, doi:10.1117/12.535350. Full Text
Alcorn, J., et al. “Basic instrumentation for Hall A at Jefferson Lab.” Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 522, no. 3, Apr. 2004, pp. 294–346. Scopus, doi:10.1016/j.nima.2003.11.415. Full Text
Gueorguiev, G. P., et al. “Modeling Fast Neutron Shielding for the nn-Experiment.” Accelerator Applications in a Nuclear Renaissance, (American Nuclear Society, La Grange Park, Illinois), 2004.
al, KG Fissum et, and including C. R. Howell. “Dynamics of the Quasielastic 16O(e,ep) Reaction at Q2 ~ 0.8 (GeV/c)2.” Phy. Rev. C, vol. 70, 2004.
Fissum, K. G., et al. “Dynamics of the quasielastic16O(e,e′p) reaction at Q 2≈0.8 (GeV/c)2.” Physical Review C Nuclear Physics, vol. 70, no. 3, 2004, pp. 0346061–03460630. Scival, doi:10.1103/PhysRevC.70.034606. Full Text
Laveissière, G., et al. “Backward electroproduction of π0 mesons on protons in the region of nucleon resonances at four momentum transfer squared Q2=1.0 GeV2.” Physical Review C Nuclear Physics, vol. 69, no. 4, Jan. 2004. Scopus, doi:10.1103/PhysRevC.69.045203. Full Text
Tornow, W., et al. “Low-energy photodisintegration of the deuteron and Big-Bang nucleosynthesis.” Physics Letters, Section B: Nuclear, Elementary Particle and High Energy Physics, vol. 574, no. 1–2, Nov. 2003, pp. 8–13. Scopus, doi:10.1016/j.physletb.2003.08.078. Full Text
Reichelt, T., et al. “Measurement of the neutron electric form factor via recoil polarimetry.” European Physical Journal A, vol. 18, no. 2–3, Oct. 2003, pp. 181–83. Scopus, doi:10.1140/epja/i2002-10296-0. Full Text
Madey, R., et al. “Measurements of GEn/GMn from the 2H(e→, e′n→)1H Reaction to Q2 = 1.45 (GeV/c)2.” Physical Review Letters, vol. 91, no. 12, Sept. 2003, pp. 1220021–25.