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Quasielastic (e,e{prime}p) scattering at large momentum transfer

Description: Coincidence cross sections for (e, e{prime} p) quasi-elastic scattering were measured at CEBAF with high statistical precision for C, Fe, and Au targets for 0.6 < Q{sup 2} < 3.3 GeV{sup 2}. Missing energy and missing momentum distributions obtained from a preliminary analysis are in reasonable agreement with prior data from SLAC. The preliminary results are compared with a PWIA calculation to determine the nuclear transparency as a function of Q{sup 2} and A. At both A{sup 2} = 0.6 and Q{sup 2} = 1.8 GeV{sup 2} data were taken to perform a Rosenbluth separation to extract the longitudinal and transverse cross sections. The preliminary missing-energy distributions of the forward and backward angle measurements do not indicate an obvious excess of transverse strength.
Date: August 1, 1997
Creator: Ent, R.; Abbott, D. & Dunne, J.
Partner: UNT Libraries Government Documents Department

Measurement of color transparency by C(p,2p) reactions at large momentum transfer

Description: The subject of color transparency, the enhancement of the ability of hadrons to penetrate nuclear matter by kinematic selection, is both interesting and controversial. The description of the collision of hadrons with nucleons inside nuclei, and the connection with initial and final state interactions involve fundamental questions of quantum mechanics, and nuclear and particle physics. Interest in color transparency was greatly increased by AGS Experiment 834 which observed dramatic changes with incident momentum for a variety of nuclei. A new experiment, E850, has studied the (p,2p) quasi-elastic reaction near 90{degree} cm for momenta between 5.9 and 9 GeV/c. The quasi-elastic reaction was compared to the elastic reaction on free protons to determine the transparency. With limited statistics, but with better kinematic definition in a new detector, the authors have confirmed the rise in Carbon transparency ratio seen in Expt 834. The Tr(D/H) for deuterium is consistent with no energy dependence. Unlike the free d{sigma}/dt for hydrogen, the d{sigma}/dt from protons in a nucleus is consistent with the exact s{sup {minus}10} scaling. This suggests two components to the pp scattering amplitude; one small and perturbative, the other spatially large and varying, but filtered away by the nuclear matter in the Carbon nucleus. The plan is to complete the repairs of the superconducting solenoid early this fall, reassemble the detector, and collect data starting next spring.
Date: December 1, 1997
Creator: Carroll, A.S. & Collaboration, E850
Partner: UNT Libraries Government Documents Department

Measurements of elastic and quasi-elastic scatterings of pp and -pp from ~ 20 to 40 GeV/c

Description: We propose a systematic study of elastic and quasi-elastic scatterings of pp and {bar p}p in the forward region (|t{vert_bar} {approx}&lt; 1.5 GeV{sup 2}) from {approx} 20 to 40 GeV/c by using the single-arm spectrometer of NAL Exp. 7 without any essential change. The physics interests in this energy region warrant a precise comparison between pp and {bar p}p as a function of s(t) for fixed t(s). Therefore it is essential to use the same experimental apparatus and analysis procedures in order to minimize possible systematic errors. The possible future experiments at Serpukhov will not be able to produce sufficient flux in the secondary {bar p} beams to answer the physics questions raised in this proposal.
Date: July 1, 1971
Creator: Lai, K.W.; Turkot, F.; Gordon, H.A.; Schublein, P.; /Brookhaven; Cords, D. et al.
Partner: UNT Libraries Government Documents Department

Recent results for (e,e{prime}p) reactions at Jefferson Lab

Description: Coincidence cross sections for (e, e{prime}p) quasi-elastic scattering were measured at CEBAF with high statistical precision for C, Fe, and Au targets for 0.6 < Q{sup 2} < 3.3 GeV{sup 2}. Missing energy and missing momentum distributions obtained from a preliminary analysis are in reasonable agreement with prior data from SLAC. The preliminary analysis are compared with a PWIA calculation to determine the nuclear transparency as a function of Q{sup 2} and A. A Rosenbluth analysis to extract the longitudinal and transverse cross sections from these data is anticipated.
Date: September 1, 1997
Creator: Potterveld, D.; Cummings, W.J. & Geesaman, D.F.
Partner: UNT Libraries Government Documents Department

Precise measurement of the neutron magnetic form factor from quasielastic {sup 3}{rvec H}e({rvec e},e`)

Description: Polarized {sup 3}He targets have proven to be a useful tool for studying the electric and magnetic form factors of the neutron, and the spin structure of the neutron. The neutron magnetic form factor at low Q{sup 2} was determined previously at MIT-Bates from the quasielastic {sup 3}{ital {rvec H}e({rvec e}, e{sup `})} process. New experiment was planned at TJNAF to systematically measure the inclusive {sup 3}He quasielastic transverse asymmetry, A{sub T{sup `}}, at Q{sup 2} = 0.1 - 0.5 (GeV/c){sup 2} with high statistical and systematic accuracy. A 2% statistical uncertainty is aimed at all the pro- posed values of Q{sup 2} , and 3% systematic uncertainty for A{sub T{sup `}} can be achieved for this experiment. The precise data will constrain theoretical calculations of {sup 3}He quasielastic asymmetry. Furthermore, the neutron magnetic form factor at Q{sup 2} = 0.1 - 0.5 (GeV/c){sup 2} will be extracted from the measured asymmetries with an overall uncertainty of 2%. Precise measurements of {ital G{sup n}{sub M}} at low Q{sup 2} will resolve the discrepancy among the existing data in the same Q{sup 2} region.
Date: February 1, 1997
Creator: Gao, H.
Partner: UNT Libraries Government Documents Department

A-dependence of nuclear transparency in quasielastic A(e,e{prime}p) at high Q{sup 2}

Description: The A-dependence of the quasielastic A(e,e{prime}p) reaction has been studied with {sup 3}H, C, Fe, and Au nuclei at momentum transfers Q{sup 2} = 1, 3, 5, and 6.8(GeV/c){sup 2}. The authors extract the nuclear transparency T(A,Q{sup 2}), a measure of the average probability of escape of a proton from a nucleus A. Several calculations predict a significant increase in T with momentum transfer, a phenomenon known as color transparency. No statistically significant rise is seen for any of the nuclei studied.
Date: May 1, 1994
Creator: O`Neill, T.G.; Lorenzon, W. & Arrington, J.
Partner: UNT Libraries Government Documents Department

Proton propagation through nuclei and the quasi-free reaction mechanism studied with (e,e{prime}p) reactions

Description: Jefferson Lab experiment E91-013 measured the energy dependence of proton propagation in nuclei, using the quasi-free (e, e{prime}p) reaction. The ratios of the experimental (e, e{prime}p) cross-sections integrated over the quasi-free region to PWIA calculations are presented as a function of momentum transfer, (0.6 < Q{sup 2} < 3.3 GeV{sup 2}) and target nucleus (C, Fe and Au). As a first step towards a longitudinal and transverse separation of the quasi-free cross-section, a super ratio of the measured to the calculated cross-sections at forward and backward angles is presented.
Date: September 1, 1997
Creator: Dutta, D.; Abbott, D. & Amatuni, T.A.
Partner: UNT Libraries Government Documents Department

Recent experiments using polarization observables at Bates

Description: In this talk I summarize the experiments completed at the MIT-Bates electron accelerator in the last few years and compare their results with those of recent experiments performed elsewhere that address the same or similar physics issues. The experiments described here focus on measurements of the nucleon form factors and studies of the three-body system in inclusive quasielastic electron scattering from polarized {sup 3}He.
Date: August 1, 1995
Creator: Jones, C.E.
Partner: UNT Libraries Government Documents Department

Reorientations in plastic crystal phases of Zintl alloys

Description: Quasielastic neutron scattering measurements on the Zintl alloy NaSn show that the high-temperature solid phase discovered by Hume-Rothery is a plastic crystal characterized by rapid rotations of the Sn{sub 4}{sup (4{minus})} Zintl ions. The reorientations are similar to those previously observed in CsPb but have a markedly different wave vector dependence, indicating a different behaviour of the alkali metal ions.
Date: December 31, 1993
Creator: Saboungi, M. L.; Fortner, J.; Price, D. L. & Howells, W. S.
Partner: UNT Libraries Government Documents Department

Measurement of muon neutrino quasi-elastic scattering on carbon

Description: Low energy (200 &lt; E{sub v} &lt; 2000 MeV) neutrino oscillation experiments, including MiniBooNE, require a model of charged current quasi-elastic (CCQE) neutrino interactions to predict signal samples. Using a high-statistics sample of muon neutrino CCQE events, MiniBooNE finds that a simple Fermi gas model, with appropriate adjustments, accurately characterizes the CCQE events observed in a carbon-based detector. The extracted parameters include an effective axial mass, M{sub A} = 1.23 {+-} 0.20 GeV, used to describe the four-momentum dependence of the axial-vector form factor of the nucleon; and a Pauli-suppression parameter, {kappa} = 1.019 {+-} 0.011.
Date: June 1, 2007
Creator: Aguilar-Arevalo, A.A.; Bazarko, A.O.; Brice, S.J.; Brown, B.C.; Bugel, L.; Cao, J. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the nu(mu) Charged Current pi+ Production to Quasi-elastic Scattering Cross Section

Description: Using high statistics samples of charged current interactions, MiniBooNE reports a model independent measurement of the single charged pion production to quasi-elastic cross section ratio on mineral oil without corrections for pion re-interactions in the target nucleus [1]. The result is provided as a function of neutrino energy in the range 0.4 GeV &lt; E &lt; 2.4 GeV with 11% precision in the region of highest statistics.
Date: September 1, 2009
Creator: Nowak, Jaroslaw A. & U., /Louisiana State
Partner: UNT Libraries Government Documents Department

Studying neutrino oscillations using quasi-elastic events in MINOS

Description: MINOS (Main Injector Neutrino Oscillation Search), is a long baseline neutrino experiment designed to search for neutrino oscillations using two detectors at Fermi National Accelerator Laboratory, IL (Near Detector) and Soudan, MN (Far Detector). It will study {nu}{sub {mu}} {yields} {nu}{sub {tau}} oscillations and make a measurement on the oscillation parameters, {Delta}m{sub 23}{sup 2} and sin{sup 2} 2{theta}{sub 23}, via a {nu}{sub {mu}} beam made at Fermilab. Charge current neutrino interactions in the MINOS detectors are of three types: quasi-elastic scattering (QEL), resonance scattering (RES) and deep inelastic scattering (DIS). Of these, quasi-elastic scattering leaves the cleanest signal with just one {mu} and one proton in the final state, thus rendering the reconstruction of the neutrino energy more accurate. This thesis will outline a method to separate QEL events from the others in the two detectors and perform a calculation of {Delta}m{sub 23}{sup 2} and sin{sup 2} 2{theta}{sub 23} using those events. The period under consideration was May 2005 to February 2006. The number of observed quasi-elastic events with energies below 10 GeV was 29, where the expected number was 60 {+-} 3. A fit to the energy distribution of these events gives {Delta}m{sub 23}{sup 2} = 2.91{sub -0.53}{sup +0.49}(stat){sub -0.09}{sup +0.08}(sys) x 10{sup -3} eV{sup 2} and sin{sup 2} 2{theta}{sub 23} = 0.990{sub -0.180}(stat){sub -0.030}(sys).
Date: February 1, 2008
Creator: Kumaratunga, Sujeewa Terasita & U., /Minnesota
Partner: UNT Libraries Government Documents Department

Cross section measurements for quasi-elastic neutrino-nucleus scattering with the MINOS near detector

Description: The Main Injector Neutrino Oscillation Search (MINOS) is a long baseline neutrino oscillation experiment based at the Fermi National Accelerator Laboratory (FNAL) in Chicago, Illinois. MINOS measures neutrino interactions in two large iron-scintillator tracking/sampling calorimeters; the Near Detector on-site at FNAL and the Far Detector located in the Soudan mine in northern Minnesota. The Near Detector has recorded a large number of neutrino interactions and this high statistics dataset can be used to make precision measurements of neutrino interaction cross sections. The cross section for charged-current quasi-elastic scattering has been measured by a number of previous experiments and these measurements disagree by up to 30%. A method to select a quasi-elastic enriched sample of neutrino interactions in the MINOS Near Detector is presented and a procedure to fit the kinematic distributions of this sample and extract the quasi-elastic cross section is introduced. The accuracy and robustness of the fitting procedure is studied using mock data and finally results from fits to the MINOS Near Detector data are presented.
Date: April 1, 2008
Creator: Dorman, Mark Edward & London, /University Coll.
Partner: UNT Libraries Government Documents Department

SciNOvA: A Measurement of Neutrino-Nucleus Scattering in a Narrow-Band Beam

Description: We propose to construct and deploy a fine-grained detector in the Fermilab NOvA 2 GeV narrow-band neutrino beam. In this beam, the detector can make unique contributions to the measurement of quasi-elastic scattering, neutral-current elastic scattering, neutral-current {pi}{sup 0} production, and enhance the NOvA measurements of electron neutrino appearance. To minimize cost and risks, the proposed detector is a copy of the SciBar detector originally built for the K2K long baseline experiment and used recently in the SciBooNE experiment.
Date: October 15, 2010
Creator: Paley, J.; Djurcic, Z.; /Argonne; Harris, D.; Tesarek, R.; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

Low-energy {sup 4}He{sup +} scattering from deuterium adsorbed on stepped Pd(331)

Description: We have taken angle-resolved data for the scattering of low-energy (< I keV) {sup 4}He{sup +} from deuterium adsorbed on a stepped Pd(331) surface. The impact geometry was up the staircase, that is, the {sup 4}He{sup +} beam was perpendicular to and directly incident onto the unshadowed <011>Pd ledge atoms. A strong quasi-elastic scattering signal of {sup 4}He{sup +} from D ({sup 4}He{sup +}/D) was observed at a forward scattering angle of {theta} = 25{degrees} and an incidence angle of {alpha} = 76{degrees} from the (331) normal. The results agree with shadow cone calculations of scattering first from Pd ledge atoms followed by a second event, {sup 4}He{sup +}/D. The resultant adsorption geometry shows D to reside in the quasi- threefold ledge site on the surface directly above the bulk fcc octahedral void. These results are consistent with the previous{sup 4}He{sup +} scattering study of the geometrically related Pd(110)- D(ads) system.
Date: July 1, 1996
Creator: Ellis, W.P. & Bastasz, R.
Partner: UNT Libraries Government Documents Department

Quasi-free ({ital e,e`p}) reactions: the first look from CEBAF

Description: Coincidence cross sections for ({ital e,e{sup `}p}) quasi-elastic scattering were measured at CEBAF with high statistical precision for C, Fe, and Au targets for 0.6 {lt} Q{sup 2} {lt} 3.3 GeV{sup 2}. {ital E{sub m}} and {ital P{sub m}} distributions obtained from a preliminary analysis are in reasonable agreement with prior data from SLAC, The preliminary results are compared with a PWIA calculation to determine the nuclear transparency as a function of Q{sup 2} and A. A. Rosenbluth analysis to extract the longitudinal and transverse cross sections from these data is anticipated.
Date: November 1, 1996
Creator: Abbott, D.; Amatuoni, T. & Armstrong, C.
Partner: UNT Libraries Government Documents Department

Nuclear effects in deep inelastic scattering

Description: The authors extend the approach used to treat quasi-elastic inclusive electron-nucleus scattering to the deep inelastic region. They provide a general approach to describe lepton scattering from an off-shell nucleon, and calculate the ratio of inclusive deep inelastic scattering cross sections to the deuteron for nuclear matter and helium (EMC-effect). They find that the consistent inclusion of the binding effects, in particular the ones arising from the short-range nucleon-nucleon interaction, allows to describe the data in the region of x &gt; 0.15 where binding fully accounts for the deviation of the cross section ratios from one.
Date: March 1, 1998
Creator: Benhar, O.; Pandharipande, V.R. & Sick, I.
Partner: UNT Libraries Government Documents Department

Searching for Color Coherent effects at intermediate Q{sup 2} via double scattering processes

Description: The authors propose that measuring the Q{sup 2} dependence of the number of final-state interactions of the recoil protons in quasi-elastic electron scattering from light nuclei is a new method to investigate Color Coherent effects at intermediate values of Q{sup 2} ({approximately} few (GeV/c){sup 2}). This is instead of measuring events without final-state interactions. Their calculations indicate that such measurements could reveal significant color transparency effects for the highest of the energies initially available at CEBAF. Measurements that detect more than one hadron in the final state, which require the use of large acceptance (4{pi}) detectors, are required.
Date: January 1, 1994
Creator: Egiyan, K.; Sargsyan, M.; Frankfurt, L.; Greenberg, W.R.; Miller, G.R. & Strikman, M.
Partner: UNT Libraries Government Documents Department

Dynamical relativistic effects in quasielastic 1 {rho}-shell proton knockout from {sup 16}O

Description: The authors have measured the cross section for quasielastic 1 {rho}-shell proton knockout in the (sup 16)O (e, e{prime}p) reaction at {omega} = 0.439 GeV and Q{sup 2} = 0.8 (GeV/c){sup 2} for missing momentum P{sub miss} {&lt;=} 355 MeV/c. They have extracted the response functions R{sub L+TT}, R{sub T}, R{sub LT}, and the left-right asymmetry, A{sub LT}, for the 1{rho}{sub 1/2} and the 1{rho}{sub 3/2} states. The data are well described by relativistic distorted wave impulse approximation calculations. At large P{sub miss}, the structure observed in A{sub LT} indicates the existence of dynamical relativistic effects.
Date: July 1999
Partner: UNT Libraries Government Documents Department

Inclusive scattering from polarized {sup 3}He and neutron form factors

Description: Because of the lack of a free neutron target, deuterium targets had been used extensively in studying the neutron structure in the past from unpolarized electron-deuteron scattering experiments. Only recently polarized electron-deuteron scattering measurements have been performed which yield more precise information on the charge form factor of the neutron. The unique spin structure of the {sup 3}He ground state and the recent developments in polarized target technologies make polarized {sup 3}He targets very effective neutron targets. In this talk, the author reviews the current status of the polarized {sup 3}He targets and focus on the quasielastic asymmetry measurement from inclusive {sup 3}He(e,e{prime}) process and the neutron form factors. He discusses the results of the MIT-Bates experiment 88-25 and the preliminary results of the recently completed JLab experiment E95-001 in which precision measurements of the neutron magnetic form factor at low Q{sup 2} are aimed.
Date: November 1, 1999
Creator: Collaboration, Haiyan Gao for the Hall A
Partner: UNT Libraries Government Documents Department

Spin-orbit final state interaction in the framework of Glauber theory for (e,e{prime}p) reactions

Description: The authors investigate the reactions D(e,e{prime}p)n and D({rvec e},e{prime}p)n at GeV energies and discuss the opportunities to distinguish between different models for the nuclear ground state by measuring the response functions. In calculating the final-state interaction (FSI) they employ Glauber theory, and they also include relativistic effects in the electromagnetic current. They include not only the central FSI, but also the spin-orbit FSI which is usually neglected in (e,e{prime}p) calculations within the Glauber framework and they show that this contribution plays a crucial role for the fifth response function. All of the methods developed here can be applied to any target nucleus.
Date: November 1, 1998
Creator: Jeschonnek, S. & Donnelly, T.W.
Partner: UNT Libraries Government Documents Department

{sup 3}He[pol]({rvec e}, e{prime})X and the neutron electromagnetic form factors

Description: Recent data for the spin-dependent A{sub T}, and A{sub TL}, asymmetries in {sup 3}He[pol]({rvec e}, e{prime}) quasielastic scattering are reviewed. The neutron electric and magnetic form factors are extracted from the data using a plane wave impulse approximation (PWIA) model, and the model uncertainties are estimated. The extracted G{sub M}{sup n} is in agreement with the dipole prediction as well as with other recent experiments. No meaningful result for G{sub E}{sup n} is obtained due to large uncertainties and possible final-state interaction effects. At higher Q{sup 2}, the determination of G{sub E}{sup n} in {sup 3}He[pol]({rvec e},e{prime}) does appear feasible based on the plane wave impulse approximation (PWIA) predictions.
Date: December 31, 1995
Creator: Hansen, J.O.
Partner: UNT Libraries Government Documents Department

Cross section of electron - off-shell nucleon interaction

Description: The results of theoretical calculations of the electron-bound nucleon interaction cross section ({sigma}{sub eN}) are given for four theoretical approaches. It is shown that there are significant differences between predictions of these methods, especially for the deeply bound (high internal momentum, high removing energy) nucleons. To test these predictions experimentally the authors study of cross sections obtained for two primary energies or for bound proton and neutron. These ratios will be insensitive to the nuclear spectral function as well as to the off-shell modifications of the bound nucleon form-factors if every pair of measurements are made for the same values of energy and momentum-transfers, removal energy, internal and final momenta of the struke nucleon. It is shown that dependences of the discussed ratios on various kinematical parameters are significantly different in different approaches and can be used to distinguish the theoretical models used.
Date: January 1, 1993
Creator: Egiyan, K. & Sargsyan, M.
Partner: UNT Libraries Government Documents Department