Physics Research Works
Permanent URI for this collectionhttp://hdl.handle.net/1903/1597
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Item Two-Body Photodisintegration of the Deuteron up to 2.8 GeV(The American Physical Society, 1995-01) Belz, J.E.; Potterveld, D.H.; Anthony, P.; Arnold, R.G.; Arrington, J.; Beck, D.; Beise, E.J.; Bosted, P.E.; Bulten, H.-J.; Chapman, M.S.; Coulter, K.P.; Dietrich, F.; Ent, R.; Epstein, M.; Filippone, B.W.; Gao, H.; Gearhart, R.A.; Geesaman, D.F.; Hansen, J.-O.; Holt, R.J.; Jackson, H.E.; Jones, C.E.; Keppel, C.E.; Kinney, E.R.; Kuhn, S.; Lee, K.; Lorenzon, W.; Makins, N.C.R.; Lung, A.; Margaziotis, D.J.; McKeown, R.D.; Meziani, Z.E.; Milner, R.G.; Mueller, B.; Napolitano, J.; Nelson, J.; O'Neill, T.G.; Papavassiliou, V.; Petratos, G.G.; Rock, S.E.; Segel, R.E.; Spengos, M.; Szalta, Z.M.; Tao, L.H.; van Bibber, K.; van der Brand, F.J.; White, J.L.; Zeidman, B.Measurements were performed for the photodisintegration cross section of the deuteron for photon energies from 1.6 to 2.8 GeV and center-of-mass angles from 37° to 90°. The measured energy dependence of the cross section at θc.m.=90° is in agreement with the constituent counting rules.Item Momentum transfer dependence of nuclear transparency from the quasielastic 12C(e,e’p) reaction(1994-03) Makins, N.C.R.; Ent, R.; Chapman, M.S.; Hansen, J.-O.; Lee, K.; Milner, R.G.; Nelson, J.; Bosted, P.E.; Keppel, C.E.; Lung, A.; Rock, S.E.; Spengos, M.; Szalata, Z.M.; Tao, L.H.; White, J.L.; Coulter, K.P.; Geesaman, D.F.; Holt, R.J.; Jackson, H.E.; Papavassiliou, V.; Potterveld, D.H.; Zeidman, B.; Arrington, J.; Beise, E.J.; Belz, E.; Filippone, B.W.; Gao, H.; Lorenzon, W.; Mueller, B.; McKeown, R.D.; O'Neill, T.G.; Epstein, M.; Margaziotis, D.J.; Napolitano, J.; Anthony, P.L.; van Bibber, K.; Dietrich, F.S.; Gearhart, R.A.; Petratos, G.G.; Kuhn, S.E.The cross section for quasielastic 12C(e,e’p) scattering has been measured at momentum transfer Q2=1, 3, 5, and 6.8 (GeV/c)2. The results are consistent with scattering from a single nucleon as the dominant process. The nuclear transparency is obtained and compared with theoretical calculations that incorporate color transparency effects. No significant rise of the transparency with Q2 is observed.Item Evidence for virtual Compton scattering from the proton(1995-11) van der Brand, J.F.J.; Ent, R.; Anthony, P.L.; Arnold, R.G.; Arrington, J.; Beise, E.J.; Belz, J.E.; Bosted, P.E.; Bulten, H.-J.; Chapman, M.S.; Coulter, K.P.; Dietrich, F.S.; Epstein, M.; Filippone, B.W.; Gao, H.; Gearheat, R.A.; Geesaman, D.F.; Hansen, J.-O.; Holt, R.J.; Jackson, H.E.; Jones, C.E.; Margaziotis, D.J.; McKeown, R.D.; Milner, R.G.; Mueller, B.; Napolitano, J.; Nelson, J.; Keppel, C.E.; Kinney, R.D.; Kuhn, S.; Lee, K.; Lorenzon, W.; Lung, A.; Makins, N.C.R.; O'Neill, T.G.; Papavassiliou, V.; Petratos, G.; Potterveld, D.H.; Rock, S.E.; Spengos, M.; Szalata, Z.M.; Tao, L.H.; van Bibber, K.; Wasson, D.A.; White, J.L.; Zeidman, B.In virtual Compton scattering an electron is scattered off a nucleon such that the nucleon emits a photon. We show that these events can be selected experimentally, and present the first evidence for virtual Compton scattering from the proton in data obtained at the Stanford Linear Accelerator Center. The angular and energy dependence of the data is well described by a calculation that includes the coherent sum of electron and proton radiation.Item Quasielastic (e,e′p) reaction on 12C,56Fe, and 197Au(2003-12) Dutta, D.; van Westrum, D.; Abbott, D.; Ahmidouch, A.; Amatuni, A.; Armstrong, C.; Arrington, J.; Assamagan, K.A.; Bailey, K.; Baker, O.K.; Barrow, S.; Beard, K.; Beatty, D.; Beedoe, S.; Beise, E.; Belz, E.; Bochna, C.; Bosted, P.E.; Breuer, H.; Bruins, E.E.W.; Carlini, R.; Cha, J.; Chant, N.; Cothran, C.; Cummings, W.J.; Danagoulian, S.; Day, D.; DeSchepper, D.; Ducret, J.-E.; Duncan, F.; Dunne, J.; Eden, T.; Ent, R.; Fortune, H.T.; Frolov, V.; Geesaman, D.F.; Gao, H.; Gilman, R.; Gueye, P.; Hansen, J.O.; Hinton, W.; Holt, R.J.; Jackson, C.; Jackson, H.E.; Jones, C.; Kaufman, S.; Kelly, J.J.; Keppel, C.; Khandaker, M.; Kim, W.; Kinney, A.; Klein, A.; Koltenuk, D.; Kramer, L.; Lorenzon, W.; Lung, A.; McFarlane, K.; Mack, D.J.; Madey, R.; Markowitz, P.; Martin, J.; Mateos, A.; Meekins, D.; Miller, M.A.; Milner, R.; Mitchell, J.; Mohring, R.; Mkrtchyan, H.; Nathan, A.M.; Niculescu, G.; Niculescu, I.; O'Neill, T.G.; Potterveld, D.; Price, J.W.; Reinhold, J.; Salgado, C.; Schiffer, J.P.; Segel, R.E.; Stoler, P.; Suleiman, R.; Tadevosyan, V.; Tang, L.; Terburg, B.; Welch, T.P.; Williamson, C.; Wood, S.; Yan, C.; Yang, J.-C.; Yu, J.; Zeidman, B.; Zhao, W.; Zihlmann, B.We report the results from a systematic study of the quasielastic (e,e′p) reaction on 12C, 56Fe, and 197Au performed at Jefferson Lab. We have measured nuclear transparency and extracted spectral functions (corrected for radiation) over a Q2 range of 0.64–3.25 (GeV∕c)2 for all three nuclei. In addition, we have extracted separated longitudinal and transverse spectral functions at Q2 of 0.64 and 1.8 (GeV∕c)2 for these three nuclei (except for 197Au at the higher Q2). The spectral functions are compared to a number of theoretical calculations. The measured spectral functions differ in detail but not in overall shape from most of the theoretical models. In all three targets the measured spectral functions show considerable excess transverse strength at Q2=0.64 (GeV∕c)2, which is much reduced at 1.8 (GeV∕c)2.Item Measurement of longitudinal and transverse cross sections in the 3He(e,e′π+)3H reaction at W=1.6 GeV(2001-12) Gaskell, D.; Ahmidouch, A.; Ambrozewicz, P.; Anklin, H.; Arrington, J.; Assamagan, K.; Avery, S.; Bailey, K.; Baker, O.K.; Beedoe, S.; Beise, B.; Breuer, H.; Brown, D.S.; Carlini, R.; Cha, J.; Chant, N.; Cowley, A.; Danagoulian, S.; De Schepper, D.; Dunne, J.; Dutta, D.; Ent, R.; Gan, L.; Gasparian, A.; Geesaman, D.F.; Gilman, R.; Glashausser, C.; Gueye, P.; Harvey, M.; Hashimoto, O.; Hinton, W.; Hofman, G.; Jackson, C.; Jackson, H.E.; Keppel, C.; Kinney, E.; Koltenuk, D.; Lung, A.; Mack, D.; McKee, D.; Mitchell, J.; Mkrtchyan, H.; Mueller, B.; Niculescu, G.; Niculescu, I.; O'Neill, T.G.; Papavassiliou, V.; Potterveld, D.; Reinhold, J.; Roos, P.; Sawafta, R.; Segel, R.; Stepanyan, S.; Tadevosyan, V.; Takahashi, T.; Tang, L.; Terburg, B.; Van Westrum, D.; Volmer, J.; Welch, T.P.; Wood, S.; Yuan, L.; Zeidman, B.; Zihlmann, B.The coherent 3He(e,e′π+)3H reaction was measured at Q2=0.4 (GeV/c)2 and W=1.6 GeV for two values of the virtual photon polarization, ε, allowing the separation of longitudinal and transverse cross sections. The results from the coherent process on 3He were compared to H(e,e′π+)n data taken at the same kinematics. This marks the first direct comparison of these processes. At these kinematics (pπ=1.1 GeV/c), pion rescattering from the spectator nucleons in the 3He(e,e′π+)3H process is expected to be small, simplifying the comparison to π+ production from the free proton.Item Separated spectral functions for the quasifree 12C(e,e′p) reaction(2000-05) Dutta, D.; van Westrum, D.; Abbott, D.; Ahmidouch, A.; Amatuni, A.; Armstrong, C.; Arrington, J.; Assamagan, K.A.; Bailey, K.; Baker, O.K.; Barrow, S.; Beard, K.; Beatty, D.; Beedoe, S.; Beise, E.; Belz, E.; Bochna, C.; Bosted, P.E.; Breuer, H.; Bruins, E.E.W.; Carlini, R.; Cha, J.; Chant, N.; Chrien, R.E.; Cothran, C.; Cummings, W.J.; Danagoulian, S.; Day, D.; DeSchepper, D.; Ducret, J.-E.; Duncan, F.; Dunne, J.; Eden, T.; Ent, R.; Fortune, H.T.; Frolov, V.; Geesaman, D.F.; Gao, H.; Gilman, R.; Gue`ye, P.; Hansen, J.O.; Hinton, W.; Holt, R.J.; Jackson, C.; Jackson, H.E.; Jones, C.; Kaufman, S.; Kelly, J.J.; Keppel, C.; Khandaker, M.; Kim, W.; Kinney, E.; Klein, A.; Koltenuk, D.; Kramer, L.; Lorenzon, W.; McFarlane, K.; Mack, D.J.; Madey, R.; Markowitz, P.; Martin, J.; Mateos, A.; Meekins, D.; Meier, E.; Miller, M.A.; Milner, R.; Mitchell, J.; Mohring, R.; Mkrtchyan, H.; Nathan, A.M.; Niculescu, G.; Niculescu, I.; O'Neill, T.G.; Potterveld, D.; Price, J.W.; Reinhold, J.; Salgado, C.; Schiffer, J.P.; Segel, R.E.; Stoler, P.; Suleiman, R.; Sawafta, R.; Sutter, R.J.; Tadevosyan, V.; Tang, L.; Terburg, B.; Welch, T.P.; Williamson, C.; Wood, S.; Yan, C.; Jae-Choon, Yang; Yu, J.; Zeidman, B.; Zhao, W.; Zihlmann, B.A separation of the longitudinal and transverse 12C(e,e′p) cross sections in the quasifree region has been performed in parallel kinematics at Q2 of 0.64 and 1.8 GeV2 for initial proton momentum <80 MeV. The separated transverse and longitudinal spectral functions at Q2=0.64GeV2 show significant differences for missing energy between 25 and 60 MeV indicating a breakdown in the single nucleon knockout picture. The transverse spectral functions exhibit definite momentum transfer dependence.Item Coherent π0 photoproduction on the deuteron up to 4 GeV(1999-09) Meekins, D.G.; Abbott, D.J.; Ahmidouch, A.; Armstrong, C.S.; Arrington, J.; Assamagan, K.A.; Baker, O.K.; Barrow, S.P.; Beatty, D.P.; Beck, D.H.; Beedoe, S.Y.; Beise, E.J.; Belz, J.E.; Bochna, C.; Bosted, P.E.; Brash, E.J.; Breuer, H.; Cadman, R.V.; Cardman, L.; Carlini, R.D.; Cha, J.; Chant, N.S.; Collins, G.; Cothran, C.; Cummings, W.J.; Danagoulian, S.; Duncan, F.A.; Dunne, J.A.; Dutta, D.; Eden, T.; Ent, R.; Filippone, B.W.; Forest, T.A.; Fortune, H.T.; Frolov, V.V.; Gao, H.; Geesaman, D.F.; Gilman, R.; Gueye, P.L.J.; Gustafsson, K.K.; Hansen, J.-O.; Harvey, M.; Hinton, W.; Holt, R.J.; Jackson, H.E.; Keppel, C.E.; Khandaker, M.A.; Kinney, E.R.; Klein, A.; Koltenuk, D.M.; Kumbartzki, G.; Lung, A.F.; Mack, D.J.; Madey, R.; Markowitz, P.; McFarlane, K.W.; McKeown, R.D.; Meziani, Z.-E.; Miller, M.A.; Mitchell, J.H.; Mkrtchyan, H.G.; Mohring, R.M.; Napolitano, J.; Nathan, A.M.; Niculescu, G.; Niculescu, I.; O'Neill, T.G.; Owen, B.R.; Pate, S.F.; Potterveld, D.H.; Price, J.W.; Rakness, G.L.; Ransome, D.; Reinhold, J.; Rutt, P.M; Salgado, C.W.; Savage, G.; Segel, R.E.; Simicevic, N.; Stoler, P.; Suleiman, R.; Tang, L.; Terburg, B.P.; van Westrum, D.; Vulcan, W.F.; Williamson, S.E.; Witkowski, M.T.; Wood, S.A.; Yan, C.; Zeidman, B.The differential cross section for 2H(γ,d)π0 has been measured at deuteron center-of-mass angles of 90° and 136°. This work reports the first data for this reaction above a photon energy of 1 GeV, and permits a test of the apparent constituent counting rule and reduced nuclear amplitude behavior as observed in elastic ed scattering. Measurements were performed up to a photon energy of 4.0 GeV, and are in good agreement with previous lower energy measurements. Overall, the data are inconsistent with both constituent-counting rule and reduced nuclear amplitude predictions.Item Inclusive electron scattering from nuclei at x≃1(1996-05) Arrington, J.; Anthony, P.; Arnold, R.G.; Beise, E.J.; Belz, J.E.; Bosted, P.E.; Bulten, H.-J.; Chapman, M.S.; Coulter, K.P.; Dietrich, F.; Ent, R.; Epstein, M.; Filippone, B.W.; Gao, H.; Gearhart, R.A.; Geesaman, D.F.; Hansen, J.-O.; Holt, R.J.; Jackson, H.E.; Jones, C.E.; Keppel, C.E.; Kinney, E.R.; Kuhn, S.; Lee, K.; Lorenzon, W.; Lung, A.; Makins, N.C.R.; Margaziotis, D.J.; McKeown, R.D.; Milner, R.G.; Mueller, B.; Napolitano, J.; Nelson, J.; O'Neill, T.G.; Papavassiliou, V.; Petratos, G.G.; Potterveld, D.H.; Rock, S.E.; Spengos, M.; Szalata, Z.M.; Tao, L.H.; van Bibber, K.; van den Brand, J.F.J.; White, J.L.; Winter, D.; Zeidman, B.The inclusive A(e,e′) cross section for x≃1 was measured on 2H, C, Fe, and Au for momentum transfers Q2 from 1 to 6.8 (GeV/c)2. The scaling behavior of the data was examined in the region of transition from y scaling to x scaling. Throughout this transitional region, the data exhibit ξ scaling, reminiscent of the Bloom-Gilman duality seen in free nucleon scattering.