Browsing by Author "Kelly, J.J."
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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 Quasifree (e,e′p) Reactions and Proton Propagation in Nuclei(American Physical Society, 1998-06-08) Abbott, D.; Ahmidouch, A.; Amatuni, Ts. 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.; 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.; Dutta, D.; 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.E.; 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.; 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.O.; Segel, R.E.; Stoler, P.; Suleiman, R.; Tadevosyan, V.; Tang, L.; Terburg, B.; van Westrum, D.; Welch, P.; Williamson, C.; Wood, S.; Yan, C.; Yang, Jae-Choon; Yu, J.; Zeidman, B.; Zhao, W.; Zihlmann, B.The ( e,e′p) reaction was studied on targets of C, Fe, and Au at momentum transfers squared Q2 of 0.6, 1.3, 1.8, and 3.3 GeV2 in a region of kinematics dominated by quasifree electron-proton scattering. Missing energy and missing momentum distributions are reasonably well described by plane wave impulse approximation calculations with Q2 and A dependent corrections that measure the attenuation of the final state protons.Item Recoil Polarization for Δ Excitation in Pion Electroproduction(American Physical Society, 2005-09-02) Kelly, J.J.; Roche, R.E.; Chai, Z.; Jones, M.K.; Gayou, O.; Sarty, A.J.; Frullani, S.; Aniol, K.; Beise, E.J.; Benmokhtar, F.; Bertozzi, W.; Boeglin, W.U.; Botto, T.; Brash, E.J.; Breuer, H.; Brown, E.; Burtin, E.; Calarco, J.R.; Cavata, C.; Chang, C.C.; Chant, N.S.; Chen, J.-P.; Coman, M.; Crovelli, D.; De Leo, R.; Dieterich, S.; Escoffier, S.; Fissum, K.G.; Garde, V.; Garibaldi, F.; Georgakopoulus, S.; Gilad, S.; Gilman, R.; Glashausser, C.; Hansen, J.-O.; Higinbotham, D.W.; Hotta, A.; Huber, G.M.; Ibrahim, H.; Iodice, M.; de Jager, C.W.; Jiang, X.; Klimenko, A.; Kozlov, A.; Kumbartzki, G.; Kuss, M.; Lagamba, L.; Laveissiere, G.; LeRose, J.J.; Lindgren, R.A.; Liyanage, N.; Lolos, G.J.; Lourie, R.W.; Margaziotis, D.J.; Marie, F.; Markowitz, P.; McAleer, S.; Meekins, D.; Michaels, R.; Milbrath, B.D.; Mitchell, J.; Nappa, J.; Neyret, D.; Perdrisat, C.F.; Potokar, M.; Punjabi, V.A.; Pussieux, T.; Ransome, R.D.; Roos, P.G.; Rvachev, M.; Saha, A.; Sirca, S.; Suleiman, R.; Strauch, S.; Templon, J.A.; Todor, L.; Ulmer, P.E.; Urciuoli, G.M.; Weinstein, L.B.; Wijesooriya, K.; Wojtsekhowski, B.; Zheng, X.; Zhu, L.; Jefferson Laboratory E91011 and Hall A CollaborationsWe measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W=1.23 GeV at Q2=1.0 (GeV/c)2, obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have been observed for the first time. Dynamical models do not describe quantities governed by imaginary parts of interference products well, indicating the need for adjusting magnitudes and phases for nonresonant amplitudes. We performed a nearly model-independent multipole analysis and obtained values for Re (S1+/M1+)=-(6.84±0.15)% and Re (E1+/M1+)=-(2.91±0.19)% that are distinctly different from those from the traditional Legendre analysis based upon M1+ dominance and ℓπ≤1 truncation.Item Recoil polarization measurements for neutral pion electroproduction at Q2=1(GeV/c)2 near the Δ resonance(2007-02) Kelly, J.J.; Gayou, O.; Roche, R.E.; Chai, Z.; Jones, M.K.; Sarty, A.J.; Frullani, S.; Aniol, K.; Beise, E.J.; Benmokhtar, F.; Bertozzi, W.; Boeglin, W.U.; Botto, T.; Brash, E.J.; Breuer, H.; Brown, E.; Burtin, E.; Calarco, J.R.; Cavata, C.; Chang, C.C.; Chant, N.S.; Chen, J.-P.; Coman, M.; Crovelli, D.; De Leo, R.; Dieterich, S.; Escoffier, S.; Fissum, K.G.; Garde, V.; Garibaldi, F.; Georgakopoulos, S.; Gilad, S.; Gilman, R.; Glashausser, C.; Hansen, J.-O.; Higinbotham, D.W.; Hotta, A.; Huber, G.M.; Ibrahim, H.; Iodice, M.; de Jager, C.W.; Jiang, X.; Kimenko, A.; Kozlov, A.; Kumbartzki, G.; Kuss, M.; Lagamba, L.; Laveissiere, G.; LeRose, J.J.; Lindgren, R.A.; Liyange, N.; Lolos, G.J.; Lourie, R.W.; Margaziotis, D.J.; Marie, F.; Markowitz, P.; McAleer, S.; Meekins, D.; Michaels, R.; Milbrath, B.D.; Mitchell, J.; Nappa, J.; Neyret, D.; Perdrisat, C.F.; Potokar, M.; Punjabi, V.A.; Pussieux, T.; Ransome, R.D.; Roos, P.G.; Rvachev, M.; Saha, A.; Sirca, S.; Suleiman, R.; Strauch, S.; Templon, J.A.; Todor, L.; Ulmer, P.E.; Urciuoli, G.M.; Weinstein, L.B.; Wijsooriya, K.; Wojtsekhowski, B.; Zheng, X.; Zhu, L.; Jefferson Laboratory E91011 and Hall A CollaborationsWe measured angular distributions of differential cross section, beam analyzing power, and recoil polarization for neutral pion electroproduction at Q2=1.0 (GeV/c)2 in 10 bins of 1.17⩽W⩽1.35 GeV across the Δ resonance. A total of 16 independent response functions were extracted, of which 12 were observed for the first time. Comparisons with recent model calculations show that response functions governed by real parts of interference products are determined relatively well near the physical mass, W=MΔ≈1.232 GeV, but the variation among models is large for response functions governed by imaginary parts, and for both types of response functions, the variation increases rapidly with W>MΔ. We performed a multipole analysis that adjusts suitable subsets of ℓπ⩽2 amplitudes with higher partial waves constrained by baseline models. This analysis provides both real and imaginary parts. The fitted multipole amplitudes are nearly model independent—there is very little sensitivity to the choice of baseline model or truncation scheme. By contrast, truncation errors in the traditional Legendre analysis of N→Δ quadrupole ratios are not negligible. Parabolic fits to the W dependence around MΔ for the multiple analysis gives values for Re(S1+/M1+)=(-6.61±0.18)% and Re(E1+/M1+)=(-2.87±0.19)% for the pπ0 channel at W=1.232 GeV and Q2=1.0 (GeV/c)2 that are distinctly larger than those from the Legendre analysis of the same data. Similarly, the multipole analysis gives Re(S0+/M1+)=(+7.1±0.8)% at W=1.232 GeV, consistent with recent models, while the traditional Legendre analysis gives the opposite sign because its truncation errors are quite severe.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.