Science.gov

Sample records for proton elastic scattering

  1. Proton Nucleus Elastic Scattering Data.

    Energy Science and Technology Software Center (ESTSC)

    1993-08-18

    Version 00 The Proton Nucleus Elastic Scattering Data file PNESD contains the numerical data and the related bibliography for the differential elastic cross sections, polarization and integral nonelastic cross sections for elastic proton-nucleus scattering.

  2. Elastic proton-proton scattering at RHIC

    SciTech Connect

    Yip, K.

    2011-09-03

    Here we describe elastic proton+proton (p+p) scattering measurements at RHIC in p+p collisions with a special optics run of {beta}* {approx} 21 m at STAR, at the center-of-mass energy {radical}s = 200 GeV during the last week of the RHIC 2009 run. We present preliminary results of single and double spin asymmetries.

  3. Intermediate energy proton-deuteron elastic scattering

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.

    1973-01-01

    A fully symmetrized multiple scattering series is considered for the description of proton-deuteron elastic scattering. An off-shell continuation of the experimentally known twobody amplitudes that retains the exchange symmeteries required for the calculation is presented. The one boson exchange terms of the two body amplitudes are evaluated exactly in this off-shell prescription. The first two terms of the multiple scattering series are calculated explicitly whereas multiple scattering effects are obtained as minimum variance estimates from the 146-MeV data of Postma and Wilson. The multiple scattering corrections indeed consist of low order partial waves as suggested by Sloan based on model studies with separable interactions. The Hamada-Johnston wave function is shown consistent with the data for internucleon distances greater than about 0.84 fm.

  4. Differential Cross Sections for Proton-Proton Elastic Scattering

    NASA Technical Reports Server (NTRS)

    Norman, Ryan B.; Dick, Frank; Norbury, John W.; Blattnig, Steve R.

    2009-01-01

    Proton-proton elastic scattering is investigated within the framework of the one pion exchange model in an attempt to model nucleon-nucleon interactions spanning the large range of energies important to cosmic ray shielding. A quantum field theoretic calculation is used to compute both differential and total cross sections. A scalar theory is then presented and compared to the one pion exchange model. The theoretical cross sections are compared to proton-proton scattering data to determine the validity of the models.

  5. Proton-Proton Elastic Scattering Excitation Functions at Intermediate Energies

    SciTech Connect

    Bisplinghoff, J.; Daniel, R.; Diehl, O.; Engelhardt, H.; Ernst, J.; Eversheim, P.; Gro-Hardt, R.; Heider, S.; Heine, A.; Hinterberger, F.; Jahn, R.; Jeske, M.; Lahr, U.; Maschuw, R.; Mayer-Kuckuk, T.; Mosel, F.; Rohdje, H.; Rosendaal, D.; Ro, U.; Scheid, H.; Schulz-Rojahn, M.; Schwandt, F.; Schwarz, V.; Trelle, H.; Wiedmann, W.; Ziegler, R.; Albers, D.; Bollmann, R.; Bueer, K.; Dohrmann, F.; Gasthuber, M.; Greiff, J.; Gro, A.; Igelbrink, M.; Langkau, R.; Lindlein, J.; Mueller, M.; Muenstermann, M.; Schirm, N.; Scobel, W.; Wellinghausen, A.; Woller, K.; Cloth, P.; Gebel, R.; Maier, R.; Prasuhn, D.; von Rossen, P.; Sterzenbach, G.

    1997-03-01

    Excitation functions of proton-proton elastic scattering cross sections have been measured in narrow steps for projectile momenta p{sub p} (energies T{sub p}) from 1100 to 3300MeV/c (500 to 2500MeV) in the angular range 35{degree}{le}{Theta}{sub c.m.}{le}90{degree} with a detector providing {Delta}{Theta}{sub c.m.}{approx}1.4{degree} resolution. Measurements have been performed continuously during projectile acceleration in the cooler synchrotron COSY with an internal CH{sub 2} fiber target, taking particular care to monitor luminosity as a function of T{sub p}. The advantages of this experimental technique are demonstrated, and the excitation functions obtained are compared to existing cross section data. No evidence for narrow structures was found. {copyright} {ital 1997} {ital The American Physical Society}

  6. Two-photon exchange and elastic electron-proton scattering

    SciTech Connect

    Peter Blunden; Wally Melnitchouk; John Tjon

    2003-06-01

    Two-photon exchange contributions to elastic electron-proton scattering cross sections are evaluated in a simple hadronic model including the finite size of the proton. The corrections are found to be small, but with a strong angular dependence at fixed Q{sup 2}. This is significant for the Rosenbluth technique for determining the ratio of electric and magnetic form factors of the proton, and partly reconciles the apparent discrepancy with the results of the polarization transfer technique.

  7. Electron- and positron-proton elastic scattering in CLAS

    SciTech Connect

    L.B. Weinstein

    2009-08-01

    There is a significant disagreement between measurements of the proton electric form factor, G{sup p}{sub E}, using Rosenbluth separations and polarization transfer. This disagreement, if not explained, could pose a fundamental challenge to our understanding of electron scattering or proton structure. Two-photon exchange (TPE) processes, although not fully calculable, are the most likely explanation of this disagreement. We will definitively test this assertion by comparing the electron-proton and positron-proton elastic scattering cross section in the Jefferson Lab CLAS. We will make a mixed identical electron and positron tertiary beam by passing a 5.5 GeV primary electron beam through a radiator to make a photon beam and then passing the photon beam through a converter to make electron-positron pairs. Measuring the elastic cross sections simultaneously using identical lepton beams should significantly reduce systematic uncertainties.

  8. Electron- and positron-proton elastic scattering in CLAS

    SciTech Connect

    Weinstein, L. B.

    2009-09-02

    There is a significant disagreement between measurements of the proton electric form factor, G{sup p}{sub E}, using Rosenbluth separations and polarization transfer. This disagreement, if not explained, could pose a fundamental challenge to our understanding of electron scattering or proton structure. Two-photon exchange (TPE) processes, although not fully calculable, are the most likely explanation of this disagreement. We will definitively test this assertion by comparing the electron-proton and positron-proton elastic scattering cross section in the Jefferson Lab CLAS. We will make a mixed identical electron and positron tertiary beam by passing a 5.5 GeV primary electron beam through a radiator to make a photon beam and then passing the photon beam through a converter to make electron-positron pairs. Measuring the elastic cross sections simultaneously using identical lepton beams should significantly reduce systematic uncertainties.

  9. Elastic Lambda-proton Scattering in CLAS

    NASA Astrophysics Data System (ADS)

    Price, John; CLAS Collaboration

    2016-03-01

    The Λ-proton reaction is important to our understanding of the structure of the proton and the nature of the strong nuclear force. Most previous measurements used bubble chambers with kaon beams to produce the Λ ``beam'', which then interacted with a second proton inside the chamber. The Λ can also be produced in the process γp -->K+ Λ , which has been studied at Jefferson Lab by the CLAS Collaboration. The long decay length of the Λ allows it to interact with a second proton in the target, leading to the process Λp --> Λp . The large acceptance of CLAS makes it a good choice for the study of this final state. A data-mining project was initiated with the CLAS g12 run, which used a tagged photon beam with 3.6

  10. Parity Violation in Forward Angle Elastic Electron Proton Scattering

    SciTech Connect

    Krishna Kumar

    1999-07-01

    HAPPEX is a new experiment to probe the strange structure of the nucleon with parity violating electron scattering. We describe the physics motivation, provide an experimental overview and report on the results from the first data run. The asymmetry for the elastic scattering of 3.3 GeV electrons off target protons at a scattering angle of 12.5 degrees was measured to a precision of 15% of itself. The contribution from strange quark form factors was found to be zero within the experimental and theoretical uncertainties.

  11. Proton-proton and proton-antiproton elastic scattering at high energies: Theory, phenomenology, and experiment

    SciTech Connect

    Wu, Tai Tsun.

    1990-01-01

    This is a brief review of the progress in the understanding, during the past twenty years, of hadronic elastic scattering near the forward direction at high energies. On the basis of quantum gauge field theories, the Pomeron is found to be a branch cut above 1. Using the physical picture that this result implies, phenomenology for proton-proton and antiproton-proton elastic scattering is constructed. Two noteworthy features are that, at high energies, both the total cross section and the ratio of the integrated elastic cross section to the total cross section to the total cross section are increasing functions of the center-of-mass energy. Detailed predictions are given for the elastic differential cross sections, Coulomb interference and the ratios of the real to imaginary parts of the forward amplitudes. These predictions have been extensively and accurately confirmed by experiments, and have also been given both for future experiments on existing accelerators and for experiments on future accelerators. 14 refs., 2 figs.

  12. Proton-proton and proton-antiproton elastic scattering at high energies: Theory, phenomenology, and experiment

    SciTech Connect

    Wu, Tai Tsun

    1990-12-31

    This is a brief review of the progress in the understanding, during the past twenty years, of hadronic elastic scattering near the forward direction at high energies. On the basis of quantum gauge field theories, the Pomeron is found to be a branch cut above 1. Using the physical picture that this result implies, phenomenology for proton-proton and antiproton-proton elastic scattering is constructed. Two noteworthy features are that, at high energies, both the total cross section and the ratio of the integrated elastic cross section to the total cross section to the total cross section are increasing functions of the center-of-mass energy. Detailed predictions are given for the elastic differential cross sections, Coulomb interference and the ratios of the real to imaginary parts of the forward amplitudes. These predictions have been extensively and accurately confirmed by experiments, and have also been given both for future experiments on existing accelerators and for experiments on future accelerators. 14 refs., 2 figs.

  13. Parity Violation in Forward Angle Elastic Electron-Proton Scattering

    SciTech Connect

    Miller, IV, Grady Wilson

    2001-01-01

    We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton at Jefferson Laboratory. The kinematic point ({theta}_lab = 12.3 deg. and (Q^2) = 0.48 (GeV/c)^2) is chosen to provide sensitivity to the strange electric form factor G^s_E. A 3.36 GeV beam of longitudinally polarized electrons was scattered from protons in a liquid hydrogen target. The scattered flux was detected by a pair of spectrometers which focussed the elastically-scattered electrons onto total-absorption detectors. The detector signals were integrated and digitized by a custom data acquisition system. A feedback system reduced systematic errors by controlling helicity-correlated beam intensity differences at the sub-ppm (part per million) level. The experimental result, A = 14.5 +/- 2.0 (stat) +/- 1.1 (syst) ppm, is consistent with the electroweak Standard Model with no additional contributions from strange quarks. In particular, the measurement implies G^S_E + 0.39 G^s_M = 0.023 +/- 0.040 +/- 0.026 ({delta}G^n_E), where the last uncertainty is due to the estimated uncertainty in the neutron electric form factor G^n_E . This result represents the first experimental constraint of the strange electric form factor.

  14. The recoil proton polarization in. pi. p elastic scattering

    SciTech Connect

    Seftor, C.J.

    1988-09-01

    The polarization of the recoil proton for ..pi../sup +/p and ..pi../sup -/p elastic scattering has been measured for various angles at 547 MeV/c and 625 MeV/c by a collaboration involving The George Washington University; the University of California, Los Angeles; and Abilene Christian University. The experiment was performed at the P/sup 3/ East experimental area of the Los Alamos Meson Physics Facility. Beam intensities varied from 0.4 to 1.0 x 10/sup 7/ ..pi../sup -/'s/sec and from 3.0 to 10.0 x 10/sup 7/ ..pi../sup +/'s/sec. The beam spot size at the target was 1 cm in the horizontal direction by 2.5 cm in the vertical direction. A liquid-hydrogen target was used in a flask 5.7 cm in diameter and 10 cm high. The scattered pion and recoil proton were detected in coincidence using the Large Acceptance Spectrometer (LAS) to detect and momentum analyze the pions and the JANUS recoil proton polarimeter to detect and measure the polarization of the protons. Results from this experiment are compared with previous measurements of the polarization, with analyzing power data previously taken by this group, and to partial-wave analysis predictions. 12 refs., 53 figs., 18 tabs.

  15. Elastic proton-deuteron scattering at intermediate energies

    SciTech Connect

    Ramazani-Moghaddam-Arani, A.; Amir-Ahmadi, H. R.; Biegun, A.; Eslami-Kalantari, M.; Joulaeizadeh, L.; Kalantar-Nayestanaki, N.; Mardanpour, H.; Messchendorp, J. G.; Moeini, H.; Shende, S. V.; Bacher, A. D.; Bailey, C. D.; Stephenson, E. J.; Gasparic, I.; Kistryn, St.; Sworst, R.; Kozela, A.; Micherdzinska, A. M.; Stephan, E.

    2008-07-15

    Observables in elastic proton-deuteron scattering are sensitive probes of the nucleon-nucleon interaction and three-nucleon force effects. The present experimental database for this reaction is large, but contains a large discrepancy between data sets for the differential cross section taken at 135 MeV/nucleon by two experimental research groups. This article reviews the background of this problem and presents new data taken at Kernfysisch Versneller Instituute (KVI). Differential cross sections and analyzing powers for the {sup 2}H(p-vector,d)p and {sup 1}H(d-vector,d)p reactions at 135 MeV/nucleon and 65 MeV/nucleon, respectively, have been measured. The differential cross-section data differ significantly from previous measurements and consistently follow the energy dependence as expected from an interpolation of published data taken over a large range at intermediate energies.

  16. Small angle elastic scattering of protons off of spinless nuclei

    SciTech Connect

    Ling, A.G.

    1988-07-01

    Elastic differential cross sections and analyzing powers for 800 MeV protons incident on /sup 12/C, /sup 40/Ca, and /sup 208/Pb in the momentum transfer range 20 MeV/c < q < 130 MeV/c have been measured. The data was taken with the High Resolution Spectrometer (HRS) at the Los Alamos Meson Physics Facility. Special delay-line drift chambers with dead regions for the beam to pass through them were used to obtain the data. Through the interference of the Coulomb and nuclear contributions to the differential cross section in the small angle region, the ratio of the real to imaginary part of the forward nuclear amplitude ..cap alpha../sub n/(0) = Ref/sub n/(0)/Imf/sub n/(0) is extracted. The importance of knowing this quantity at lower energies in order to study the differences between relativistic and non-relativistic scattering theories is discussed. 130 refs., 60 figs., 12 tabs.

  17. Proton form factors and two-photon exchange in elastic electron-proton scattering

    SciTech Connect

    Nikolenko, D. M.; Arrington, J.; Barkov, L. M.; Vries, H. de; Gauzshtein, V. V.; Golovin, R. A.; Gramolin, A. V.; Dmitriev, V. F.; Zhilich, V. N.; Zevakov, S. A.; Kaminsky, V. V.; Lazarenko, B. A.; Mishnev, S. I.; Muchnoi, N. Yu.; Neufeld, V. V.; Rachek, I. A.; Sadykov, R. Sh.; Stibunov, V. N.; Toporkov, D. K.; Holt, R. J.; and others

    2015-05-15

    Proton electromagnetic form factors are among the most important sources of information about the internal structure of the proton. Two different methods for measuring these form factors, the method proposed by Rosenbluth and the polarization-transfer method, yield contradictory results. It is assumed that this contradiction can be removed upon taking into account the hard part of the contribution of two-photon exchange to the cross section for elastic electron-proton scattering. This contribution can measured experimentally via a precision comparison of the cross sections for the elastic scattering of positrons and electrons on protons. Such a measurement, performed at the VEPP-3 storage ring in Novosibirsk at the beam energies of 1.6 and 1.0 GeV for positron (electron) scattering angles in the ranges of θ{sub e} = 15°–25° and 55°–75° in the first case and in the range of θ{sub e} = 65°–105° in the second case is described in the present article. Preliminary results of this experiment and their comparison with theoretical predictions are described.

  18. ELRADGEN: Monte Carlo generator for radiative events in elastic electron-proton scattering

    SciTech Connect

    A.V. Afanasev; I. Akushevich; A. Ilyichev; B. Niczyporuk

    2003-08-01

    We discuss the theoretical approach and practical algorithms for simulation of radiative events in elastic ep-scattering. A new Monte Carlo generator for real photon emission events in the process of elastic electron-proton scattering is presented. We perform a few consistency checks and present numerical results.

  19. Studying the proton 'radius' puzzle with μp elastic scattering

    SciTech Connect

    Gilman, R.

    2013-11-07

    The disagreement between the proton radius determined from muonic hydrogen and from electronic measurements is called the proton radius puzzle. The resolution of the puzzle remains unclear and appears to require new experimental results. An experiment to measure muon-proton elastic scattering is presented here.

  20. Spin dependence in polarized proton-proton elastic scattering at RHIC

    NASA Astrophysics Data System (ADS)

    Plyku, Donika

    The STAR (Solenoidal Tracker At RHIC - Relativistic Heavy Ion Collider) experiment is equipped with Roman Pots, insertion devices that allow detectors to be moved close to the beam for the measurement of high energy protons scattered at very small angles. This setup, together with the unique capability of RHIC to collide spin-polarized proton beams, allows STAR to study both the dynamics and the spin-dependence of the proton-proton ( pp) elastic scattering process. Silicon strip detectors, installed inside the Roman Pots, measure tracks of protons scattered diffractively at very small angles. In a dedicated run with special beam optics during the 2009 RHIC run, the collaboration collected about 20 million elastic events with transversely polarized proton beams at the center of mass energy s = 200 GeV and four momentum transfer squared (t) range of 0.003 ≤ |t| ≤ 0.035 (GeV/c) 2, where, due to the Coulomb Nuclear Interference (CNI), a measurable single spin asymmetry arises. While the electromagnetic interaction can be determined in QED, the description of the hadronic interaction at small -t scattering requires the use of nonperturbative techniques in QCD, and, phenomenological models, rather than pQCD, are used to describe the exchange mechanism. High energy diffractive scattering at small-t is dominated by the Pomeron exchange, treated in pQCD as a color singlet combination of two gluons carrying quantum numbers of the vacuum (JPC = 0++). In this dissertation, I report on a high precision measurement of the transverse single spin asymmetry A N at s = 200 GeV in pp elastic scattering at RHIC. The measured AN and its t-dependence are consistent with the absence of a hadronic spin-flip amplitude. The major contribution to the uncertainty in AN comes from the uncertainty in the beam polarization measurement. The presented results provide a precise measurement in the non-perturbative QCD regime, where experimental data are indispensable, and, a significant

  1. Measuring the Weak Charge of the Proton via Elastic Electron-Proton Scattering

    SciTech Connect

    Jones, Donald C.

    2015-10-01

    The Qweak experiment which ran in Hall C at Jefferson Lab in Newport News, VA, and completed data taking in May 2012, measured the weak charge of the proton QpW via elastic electron-proton scattering. Longitudinally polarized electrons were scattered from an unpolarized liquid hydrogen target. The helicity of the electron beam was flipped at approximately 1 kHz between left and right spin states. The Standard Model predicts a small parity-violating asymmetry of scattering rates between right and left helicity states due to the weak interaction. An initial result using 4% of the data was published in October 2013 [1] with a measured parity-violating asymmetry of -279 ± 35(stat) ± 31 (syst) ppb. This asymmetry, along with other data from parity-violating electron scattering experiments, provided the world's first determination of the weak charge of the proton. The weak charge of the proton was found to be pW = 0.064 ± 0.012, in good agreement with the Standard Model prediction of pW(SM) = 0.0708 ± 0.0003[2].

  2. On the possibility for precision measurements of differential cross sections for elastic proton-proton scattering at the Protvino accelerator

    NASA Astrophysics Data System (ADS)

    Denisov, S. P.; Kozelov, A. V.; Petrov, V. A.

    2016-03-01

    Elastic-scattering data were analyzed, and it was concluded on the basis of this analysis that precisionmeasurements of differential cross sections for elastic proton-proton scattering at the accelerator of the Institute for High Energy Physics (IHEP, Protvino, Russia) over a broad momentum-transfer range are of importance and topical interest. The layout of the respective experimental facility detecting the scattered particle and recoil proton and possessing a high momentum-transfer resolution was examined along with the equipment constituting this facility. The facility in question is able to record up to a billion events of elastic proton-proton scattering per IHEP accelerator run (20 days). Other lines of physics research with this facility are briefly discussed.

  3. Two-photon exchange correction to muon-proton elastic scattering at low momentum transfer

    NASA Astrophysics Data System (ADS)

    Tomalak, Oleksandr; Vanderhaeghen, Marc

    2016-03-01

    We evaluate the two-photon exchange (TPE) correction to the muon-proton elastic scattering at small momentum transfer. Besides the elastic (nucleon) intermediate state contribution, which is calculated exactly, we account for the inelastic intermediate states by expressing the TPE process approximately through the forward doubly virtual Compton scattering. The input in our evaluation is given by the unpolarized proton structure functions and by one subtraction function. For the latter, we provide an explicit evaluation based on a Regge fit of high-energy proton structure function data. It is found that, for the kinematics of the forthcoming muon-proton elastic scattering data of the MUSE experiment, the elastic TPE contribution dominates, and the size of the inelastic TPE contributions is within the anticipated error of the forthcoming data.

  4. Spin observables in neutron-proton elastic scattering

    SciTech Connect

    Ahmidouch, A.; Arnold, J.; van den Brandt, B.; Daum, M.; Demierre, P.; Drevenak, R.; Finger, M. |; Finger, M. Jr.; Franz, J.; Goujon, N.; Hautle, P.; Janout, Z. Jr.; Hajdas, W.; Heer, E.; Hess, R.; Koger, R.; Konter, J.A.; Lacker, H.; Lechanoine-LeLuc, C.; Lehar, F.; Mango, S.; Mascarini, C.; Rapin, D.; Roessle, E.; Schmelzbach, P.A.; Schmitt, H.; Sereni, P.; Slunecka, M.

    1995-07-15

    We describe here two experiments presently running at PSI using the NA2 polarized neutron beam. They are devoted to the measurement of 2- and 3-spin observables in {ital np} elastic scattering for kinetic energies from 230 to 590 MeV with a center of mass angular range from 60 to 180 degrees. The goal is to determine the five {ital NN} scattering amplitudes for isospin 0 in a model independent way. Preliminary results for {ital K}{sub {ital OSKO}} and {ital K}{sub {ital OSSO}} spin-transfers are presented.

  5. Normal Spin Asymmetries in Elastic Electron-Proton Scattering

    SciTech Connect

    M. Gorchtein; P.A.M. Guichon; M. Vanderhaeghen

    2004-10-01

    We discuss the two-photon exchange contribution to observables which involve lepton helicity flip in elastic lepton-nucleon scattering. This contribution is accessed through the single spin asymmetry for a lepton beam polarized normal to the scattering plane. We estimate this beam normal spin asymmetry at large momentum transfer using a parton model and we express the corresponding amplitude in terms of generalized parton distributions. We further discuss this observable in the quasi-RCS kinematics which may be dominant at certain kinematical conditions and find it to be governed by the photon helicity-flip RCS amplitudes.

  6. Measurement of the absolute differential cross section of proton-proton elastic scattering at small angles

    NASA Astrophysics Data System (ADS)

    Mchedlishvili, D.; Chiladze, D.; Dymov, S.; Bagdasarian, Z.; Barsov, S.; Gebel, R.; Gou, B.; Hartmann, M.; Kacharava, A.; Keshelashvili, I.; Khoukaz, A.; Kulessa, P.; Kulikov, A.; Lehrach, A.; Lomidze, N.; Lorentz, B.; Maier, R.; Macharashvili, G.; Merzliakov, S.; Mikirtychyants, S.; Nioradze, M.; Ohm, H.; Prasuhn, D.; Rathmann, F.; Serdyuk, V.; Schroer, D.; Shmakova, V.; Stassen, R.; Stein, H. J.; Stockhorst, H.; Strakovsky, I. I.; Ströher, H.; Tabidze, M.; Täschner, A.; Trusov, S.; Tsirkov, D.; Uzikov, Yu.; Valdau, Yu.; Wilkin, C.; Workman, R. L.; Wüstner, P.

    2016-04-01

    The differential cross section for proton-proton elastic scattering has been measured at a beam kinetic energy of 1.0 GeV and in 200 MeV steps from 1.6 to 2.8 GeV for centre-of-mass angles in the range from 12°-16° to 25°-30°, depending on the energy. A precision in the overall normalisation of typically 3% was achieved by studying the energy losses of the circulating beam of the COSY storage ring as it passed repeatedly through the windowless hydrogen target of the ANKE magnetic spectrometer. It is shown that the data have a significant impact upon the results of a partial wave analysis. After extrapolating the differential cross sections to the forward direction, the results are broadly compatible with the predictions of forward dispersion relations.

  7. TWO-PHOTON EXCHANGE IN ELECTRON-PROTON ELASTIC SCATTERING: THEORY UPDATE

    SciTech Connect

    Andrei Afanasev

    2007-05-21

    Recent theoretical developments in the studies of two-photon exchange effects in elastic electron-proton scattering are reviewed. Two-photon exchange mechanism is considered a likely source of discrepancy between polarized and unpolarized experimental measurements of the proton electric form factor at momentum transfers of several GeV$^2$. This mechanism predicts measurable effects that are currently studied experimentally.

  8. Two-photon exchange corrections in elastic lepton-proton scattering at small momentum transfer

    NASA Astrophysics Data System (ADS)

    Tomalak, Oleksandr; Vanderhaeghen, Marc

    2016-03-01

    In recent years, elastic electron-proton scattering experiments, with and without polarized protons, gave strikingly different results for the electric over magnetic proton form factor ratio. A mysterious discrepancy (``the proton radius puzzle'') has been observed in the measurement of the proton charge radius in muon spectroscopy experiments versus electron spectroscopy and electron scattering. Two-photon exchange (TPE) contributions are the largest source of the hadronic uncertainty in these experiments. We compare the existing models of the elastic contribution to TPE correction in lepton-proton scattering. A subtracted dispersion relation formalism for the TPE in electron-proton scattering has been developed and tested. Its relative effect on cross section is in the 1 - 2 % range for a low value of the momentum transfer. An alternative dispersive evaluation of the TPE correction to the hydrogen hyperfine splitting was found and applied. For the inelastic TPE contribution, the low momentum transfer expansion was studied. In addition with the elastic TPE it describes the experimental TPE fit to electron data quite well. For a forthcoming muon-proton scattering experiment (MUSE) the resulting TPE was found to be in the 0 . 5 - 1 % range, which is the planned accuracy goal.

  9. Two-photon exchange in proton elastic scattering

    NASA Astrophysics Data System (ADS)

    Bernauer, Jan C.

    2015-10-01

    Recent interest in the proton electromagnetic form factors is partly motivated by the discrepancy found in the determination of the electric-to-magnetic form factor ratio using different techniques. Results from scattering experiments using the Rosenbluth technique indicate that the form factor ratio is constant as a function of Q2 while experiments employing polarization show a clear, roughly linear, decline of the ratio. A possible explanation is the typically unaccounted for contribution of hard two-photon exchange to the scattering process. Theoretical calculations show large variations, many indicating an effect of the right sign and magnitude. Direct verification was sought by experiments at VEPP-3, Jefferson Lab and by the OLYMPUS collaboration at DESY. In the talk, I will discuss the OLYMPUS experiment and the current state of experimental and theoretical results.

  10. Two-photon exchange correction in elastic unpolarized electron-proton scattering at small momentum transfer

    NASA Astrophysics Data System (ADS)

    Tomalak, O.; Vanderhaeghen, M.

    2016-01-01

    We evaluate the two-photon exchange (TPE) correction to the unpolarized elastic electron-proton scattering at small momentum transfer Q2 . We account for the inelastic intermediate states approximating the double virtual Compton scattering by the unpolarized forward virtual Compton scattering. The unpolarized proton structure functions are used as input for the numerical evaluation of the inelastic contribution. Our calculation reproduces the leading terms in the Q2 expansion of the TPE correction and goes beyond this approximation by keeping the full Q2 dependence of the proton structure functions. In the range of small momentum transfer, our result is in good agreement with the empirical TPE fit to existing data.

  11. Determination of the proton charge radius from elastic electron-proton scattering

    NASA Astrophysics Data System (ADS)

    Horbatsch, Marko; Hessels, Eric A.

    2016-05-01

    Precisely measured electron-proton elastic scattering cross sections are reanalyzed to evaluate their strength for determining the rms charge radius (RE) of the proton. More than half of the cross sections at lowest Q2 are fit using two single-parameter form-factor models, with the first based on a dipole parametrization, and the second on a linear fit to a conformal-mapping variable. These low-Q2 fits extrapolate the slope of the form factor to Q2 = 0 and determine RE values of approximately 0.84 and 0.89 fm, respectively. Fits spanning all Q2, in which the single constants are replaced with cubic splines at larger Q2, lead to similar results for RE. We conclude that the scattering data are consistent with RE ranging from at least 0.84 to 0.89 fm, and therefore is consistent with both of the discrepant determinations of RE made using muonic and electronic hydrogen-atom spectroscopy. NSERC Canada, Canada Research Chair Program.

  12. Spin asymmetries for elastic proton scattering and the spin-dependent couplings of the Pomeron

    SciTech Connect

    Trueman, T. L.

    2008-03-01

    This paper serves as a report on the large amount of analysis done in conjunction with the polarized proton program at the Relavitistic Heavy Ion Collider at Brookhaven National Laboratory. This comprises elastic scattering data of protons on protons in colliding beam or fixed target mode and proton beams on carbon targets. In addition to providing a model for the energy dependence of the analyzing power of elastic scattering needed for proton polarimetry, it also provides some significant information about the spin dependence of dominant Regge poles. Most notably, the data indicate that the Pomeron has a significant spin-flip coupling. This allows the exploration of the double-spin flip asymmetry A{sub NN} for which some data over a wide energy range are now available, along with a concrete realization of a proposed Odderon search.

  13. Measurement and parametrization of proton elastic scattering cross sections for nitrogen

    SciTech Connect

    Radovic, I. Bogdanovic; Siketic, Z.; Jaksic, M.; Gurbich, A. F.

    2008-10-01

    The cross sections for the elastic scattering of protons from natural nitrogen at non-Rutherford scattering energies were measured at three laboratory scattering angles: 118 deg., 150 deg., and 165 deg. The experimental data were parametrized in the framework of nuclear physics models. A benchmark experiment was performed in order to prove that the excitation functions obtained in the present work can be used to adequately simulate the yield from a thick target containing nitrogen.

  14. Transverse Spin Asymmetries in the CNI Region of Elastic Proton-Proton Scattering at s=200 GeV

    NASA Astrophysics Data System (ADS)

    Svirida, Dmitry

    2016-02-01

    Precise measurements of transverse spin asymmetries in proton-proton elastic scattering at very small values of four-momentum transfer squared, t, have been performed using the Relativistic Heavy Ion Collider (RHIC) polarized proton beams. The measurements of both single and double spin asymmetries were made at the center-of-mass energy s = 200 GeV and in the region 0.003 ≤|t|≤ 0.035 (GeV/c)2, which was accessed using Roman Pot devices incorporated into the STAR experimental setup. The obtained set of asymmetries is sensitive to the poorly known hadronic contribution to the spin-flip amplitudes and provide significant constraints for the theoretical descriptions of the reaction mechanism of proton-proton elastic scattering at high energies.

  15. Benchmark measurements of non-Rutherford proton elastic scattering cross section for boron

    NASA Astrophysics Data System (ADS)

    Chiari, M.; Bianconi, M.; Bogdanović Radović, I.; Mayer, M.

    2015-01-01

    In the literature several elastic scattering cross-sections data sets are available for protons on 10B and 11B at energies and scattering angles suitable for elastic backscattering spectrometry (EBS) analysis. However, agreement between these different data sets is generally poor, with systematic differences up to 20%, well beyond the stated absolute uncertainties. To resolve the conflict between the different data sets in the absence of the evaluated cross-section data, a benchmark experiment was performed. Proton backscattering spectra were obtained with a thick uniform B4C target at beam energies in the range of 2.0-4.0 MeV and at different scattering angles, followed by a standard direct simulation with the SIMNRA code using the available experimental cross-section data. As a result, recommendation on the most appropriate data set to be used in proton EBS analysis of boron is given.

  16. Single-spin asymmetries from two-photon exchange in elastic electron proton scattering

    SciTech Connect

    A.V. Afanasev; N.P. Merenkov

    2005-02-01

    The parity-conserving single-spin beam asymmetry of elastic electron-proton scattering is induced by an absorptive part of the two-photon exchange amplitude. We demonstrate that this asymmetry has logarithmic and double-logarithmic enhancement due to contributions of hard collinear quasi-real photons. An optical theorem is used to evaluate the asymmetry in terms of the total photoproduction cross section on the proton.

  17. Mechanism of elastic and inelastic proton scattering on a {sup 15}C nucleus in diffraction theory

    SciTech Connect

    Ibraeva, E. T.; Zhusupov, M. A.; Imambekov, O.

    2012-11-15

    The amplitudes for elastic and inelastic proton scattering on the neutron-rich nucleus {sup 15}C (to its J{sup {pi}} = 5/2{sup +} level in the latter case) in inverse kinematics were calculated within Glauber diffraction theory. First- and second-order terms were taken into account in the multiple-scattering operator. The {sup 15}C wave function in the multiparticle shell model was used. This made it possible to calculate not only respective differential cross sections but also the contribution of proton scattering on nucleons occurring in different shells. The differential cross sections for elastic and inelastic scattering were calculated at the energies of 0.2, 0.6, and 1 GeV per nucleon.

  18. Modeling proton and alpha elastic scattering in liquid water in Geant4-DNA

    NASA Astrophysics Data System (ADS)

    Tran, H. N.; El Bitar, Z.; Champion, C.; Karamitros, M.; Bernal, M. A.; Francis, Z.; Ivantchenko, V.; Lee, S. B.; Shin, J. I.; Incerti, S.

    2015-01-01

    Elastic scattering of protons and alpha (α) particles by water molecules cannot be neglected at low incident energies. However, this physical process is currently not available in the "Geant4-DNA" extension of the Geant4 Monte Carlo simulation toolkit. In this work, we report on theoretical differential and integral cross sections of the elastic scattering process for 100 eV-1 MeV incident protons and for 100 eV-10 MeV incident α particles in liquid water. The calculations are performed within the classical framework described by Everhart et al., Ziegler et al. and by the ICRU 49 Report. Then, we propose an implementation of the corresponding classes into the Geant4-DNA toolkit for modeling the elastic scattering of protons and α particles. Stopping powers as well as ranges are also reported. Then, it clearly appears that the account of the elastic scattering process in the slowing-down of the charged particle improves the agreement with the existing data in particular with the ICRU recommendations.

  19. Measurements of proton-proton and proton-antiproton elastic scattering at the European Center for Nuclear Research Intersecting Storage Rings

    NASA Astrophysics Data System (ADS)

    Amos, N. A.

    Proton-proton and proton-anitproton elastic scattering were measured at the CERN Intersecting Storage rings. Using the optical theorem, the total nuclear cross sections was extracted for these collisions. By measuring the interference between the Coulomb amplitude and the nuclear amplitude rho, the ratio of the real part to the imaginary part of the forward nuclear elastic scattering amplitude was found. Further, the nuclear slope parameter was extracted in the forward direction. The elastic scattering measurements were made at small scattering angles (approx. 1 milliradian), demanding that the detectors be placed close to the beams. Normalization of the data was performed by two methods: Van der Meer calibrations were performed on sets of luminosity monitor counters, the known Coulomb differential scattering cross section fixed the normalization scale.

  20. A recoil detector for the measurement of antiproton-proton elastic scattering at angles close to 90°

    NASA Astrophysics Data System (ADS)

    Hu, Q.; Bechstedt, U.; Gillitzer, A.; Grzonka, D.; Khoukaz, A.; Klehr, F.; Lehrach, A.; Prasuhn, D.; Ritman, J.; Sefzick, T.; Stockmanns, T.; Täschner, A.; Wuestner, P.; Xu, H.

    2014-10-01

    The design and construction of a recoil detector for the measurement of recoil protons of antiproton-proton elastic scattering at scattering angles close to are described. The performance of the recoil detector has been tested in the laboratory with radioactive sources and at COSY with proton beams by measuring proton-proton elastic scattering. The results of laboratory tests and commissioning with beam are presented. Excellent energy resolution and proper working performance of the recoil detector validate the conceptual design of the KOALA experiment at HESR to provide the cross section data needed to achieve a precise luminosity determination at the PANDA experiment.

  1. Structure of light neutron-rich nuclei and mechanism of elastic proton scattering

    SciTech Connect

    Ibraeva, E. T.; Zhusupov, M. A.; Imambekov, O.

    2011-11-15

    Differential cross sections for elastic p{sup 6}He, p{sup 8}Li, and p{sup 9}Li scattering at two energies of 70 and 700 MeV per nucleon were calculated within the Glauber theory of multiple diffractive scattering. Threeparticle wave functions ({alpha}-n-n for {sup 6}He, {alpha}-t-n for {sup 8}Li, and {sup 7}Li-n-n for {sup 9}Li) were used for realistic potentials of intercluster interactions. The sensitivity of elastic scattering to proton-nucleus interaction and to the structure of nuclei was explored. In particular, the dependence of the differential cross section on the contribution of higher order collisions, on scattering on the core and peripheral nucleons, and on the contribution of small wave-function components and their asymptotic behavior was determined. A comparison with available experimental data and with the results of calculations within different formalisms was performed.

  2. A predictive theory for elastic scattering and recoil of protons from 4He

    DOE PAGESBeta

    Hupin, Guillaume; Quaglioni, Sofia; Navratil, Petr

    2014-12-08

    Low-energy cross sections for elastic scattering and recoil of protons from 4He nuclei (also known as α particles) are calculated directly by solving the Schrodinger equation for five nucleons interacting through accurate two- and three-nucleon forces derived within the framework of chiral effective field theory. Precise knowledge of these processes at various proton backscattering/recoil angles and energies is needed for the ion-beam analysis of numerous materials, from the surface layers of solids, to thin films, to fusion-reactor materials. Indeed, the same elastic scattering process, in two different kinematic configurations, can be used to probe the concentrations and depth profiles ofmore » either hydrogen or helium. Furthermore, we compare our results to available experimental data and show that direct calculations with modern nuclear potentials can help to resolve remaining inconsistencies among data sets and can be used to predict these cross sections when measurements are not available.« less

  3. Predictive theory for elastic scattering and recoil of protons from 4He

    NASA Astrophysics Data System (ADS)

    Hupin, Guillaume; Quaglioni, Sofia; Navrátil, Petr

    2014-12-01

    Low-energy cross sections for elastic scattering and recoil of protons from 4He nuclei (also known as α particles) are calculated directly by solving the Schrödinger equation for five nucleons interacting through accurate two- and three-nucleon forces derived within the framework of chiral effective field theory. Precise knowledge of these processes at various proton backscattering/recoil angles and energies is needed for the ion-beam analysis of numerous materials, from the surface layers of solids, to thin films, to fusion-reactor materials. Indeed, the same elastic scattering process, in two different kinematic configurations, can be used to probe the concentrations and depth profiles of either hydrogen or helium. We compare our results to available experimental data and show that direct calculations with modern nuclear potentials can help to resolve remaining inconsistencies among data sets and can be used to predict these cross sections when measurements are not available.

  4. A predictive theory for elastic scattering and recoil of protons from 4He

    SciTech Connect

    Hupin, Guillaume; Quaglioni, Sofia; Navratil, Petr

    2014-12-08

    Low-energy cross sections for elastic scattering and recoil of protons from 4He nuclei (also known as α particles) are calculated directly by solving the Schrodinger equation for five nucleons interacting through accurate two- and three-nucleon forces derived within the framework of chiral effective field theory. Precise knowledge of these processes at various proton backscattering/recoil angles and energies is needed for the ion-beam analysis of numerous materials, from the surface layers of solids, to thin films, to fusion-reactor materials. Indeed, the same elastic scattering process, in two different kinematic configurations, can be used to probe the concentrations and depth profiles of either hydrogen or helium. Furthermore, we compare our results to available experimental data and show that direct calculations with modern nuclear potentials can help to resolve remaining inconsistencies among data sets and can be used to predict these cross sections when measurements are not available.

  5. Two-Photon Exchange in Elastic Electron-Proton Scattering: A QCD Factorization Approach

    SciTech Connect

    Kivel, Nikolai; Vanderhaeghen, Marc

    2009-08-28

    We estimate the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer Q{sup 2}. It is shown that the leading two-photon exchange amplitude behaves as 1/Q{sup 4}, and can be expressed in a model independent way in terms of the leading twist nucleon distribution amplitudes. Using several models for the nucleon distribution amplitudes, we provide estimates for existing data and for ongoing experiments.

  6. Elastic proton scattering on tritium below the n-{sup 3}He threshold

    SciTech Connect

    Lazauskas, Rimantas

    2009-05-15

    Elastic proton scattering on the {sup 3}H nucleus is studied between p-{sup 3}H and n-{sup 3}He thresholds, in the energy region where the first excited state of the {alpha} particle is embedded in the continuum. Faddeev-Yakubovski equations are solved in configuration space by fully considering effects from isospin breaking and rigorously treating the Coulomb interaction. Different realistic nuclear Hamiltonians are tested, elucidating open problems in the description of the nuclear interaction.

  7. Collinear Photon Exchange in the Beam Normal Polarization Asymmetry of Elastic Electron-Proton Scattering

    SciTech Connect

    Andrei Afanasev; N.P. Merenkov

    2004-07-01

    The parity-conserving single-spin beam asymmetry of elastic electron-proton scattering is induced by an absorptive part of the two-photon exchange amplitude. We demonstrate that this asymmetry has logarithmic and double-logarithmic enhancement due to contributions of hard collinear quasi-real photons. An optical theorem is used to evaluate the asymmetry in terms of the total photoproduction cross section on the proton, predicting its magnitude at 20-30 parts per million for high electron beam energies and small scattering angles. At fixed 4-momentum transfers, the asymmetry is rising logarithmically with increasing electron beam energy, following the high-energy diffractive behavior of total photoproduction cross section on the proton.

  8. Large Logarithms in the Beam Normal Spin Asymmetry of Elastic Electron--Proton Scattering

    SciTech Connect

    Andrei Afanasev; Mykola Merenkov

    2004-06-01

    We study a parity-conserving single-spin beam asymmetry of elastic electron-proton scattering induced by an absorptive part of the two-photon exchange amplitude. It is demonstrated that excitation of inelastic hadronic intermediate states by the consecutive exchange of two photons leads to logarithmic and double-logarithmic enhancement due to contributions of hard collinear quasi-real photons. The asymmetry at small electron scattering angles is expressed in terms of the total photoproduction cross section on the proton, and is predicted to reach the magnitude of 20-30 parts per million. At these conditions and fixed 4-momentum transfers, the asymmetry is rising logarithmically with increasing electron beam energy, following the high-energy diffractive behavior of total photoproduction cross section on the proton.

  9. High energy proton-proton elastic scattering at the Large Hadron Collider and nucleon structure

    NASA Astrophysics Data System (ADS)

    Luddy, Richard Joseph

    To gain insight into the structure of the nucleon, we pursue the development of the phenomenological model of Islam et al. (IIFS model) for high energy elastic pp and p¯p scattering. We determine the energy dependence of the parameters of the IIFS model using the available elastic differential cross section data from SPS Collider and Tevatron and the known asymptotic behavior of sigmatot (s) and rho(s) from dispersion relation calculations and more recent analyses of Cudell et al. (COMPETE Collaboration). Next, we incorporate a high energy elastic valence quark-quark scattering amplitude into the model based on BFKL pomeron to describe small impact parameter (large | t|) pp collisions. Finally, we predict the pp elastic differential cross section at the unprecedented c.m. energy of s = 14.0 TeV at the Large Hadron Collider (LHC). This prediction assumes crucial significance---because of an approved experiment at LHC: TOTal and Elastic Measurement (TOTEM). The TOTEM group plans to measure pp elastic dsigma/dt at 14.0 TeV all the way from momentum transfer |t| = 0 to |t| ≃ 10 GeV 2. Their measurement will stringently test not only the diffraction and o-exchange descriptions of the original IIFS model, but also the additional valence quark-quark scattering contribution that we find to be dominant for large |t|. Successful quantitative verification of the predicted dsigma/dt will mean that our picture of the nucleon with an outer cloud of qq¯ condensed ground state, an inner core of topological baryonic charge, and a still smaller core of massless valence quarks provides a realistic description of nucleon structure.

  10. Dispersion Relations for Meson-Proton and Proton-Proton Forward Elastic Scattering

    NASA Astrophysics Data System (ADS)

    Alkin, A.; Cudell, J. R.; Martynov, E.

    2012-07-01

    An analysis of the data on forward {pp, bar pp, π^{±}p} and {K^{±}p} scattering is performed making use of the single- and double-subtraction integral and comparing with derivative dispersion relations for amplitudes. Various pomeron and odderon models for the total cross sections are considered and compared. The real part of the amplitude is calculated via dispersion relations. It is shown that the integral dispersion relations lead to a better description of the data for {sqrt{s} > 5 GeV}. Predictions of the considered models for the TOTEM experiment at LHC energies are given.

  11. Elastic Proton Scattering of Medium Mass Nuclei from Coupled-Cluster Theory

    SciTech Connect

    Hagen, G.; MichelN.,

    2012-01-01

    Using coupled-cluster theory and interactions from chiral effective field theory, we compute overlap functions for transfer and scattering of low-energy protons on the target nucleus 40Ca. Effects of three-nucleon forces are included phenomenologically as in-medium two-nucleon interactions. Using known asymptotic forms for one-nucleon overlap functions we derive a simple and intuitive way of computing scattering observables such as elastic scattering phase shifts and cross sections. As a first application and proof of principle, we compute phase shifts and differential interaction cross sections at energies of 9.6 and 12.44 MeV and compare with experimental data. Our computed diffraction minima are in fair agreement with experimental results, while we tend to overestimate the cross sections at large scattering angles.

  12. Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering

    SciTech Connect

    David Armstrong; Francois Arvieux; Razmik Asaturyan; Todd Averett; Stephanie Bailey; Guillaume Batigne; Douglas Beck; Elizabeth Beise; Jay Benesch; Louis Bimbot; James Birchall; Angela Biselli; Peter Bosted; Elodie Boukobza; Herbert Breuer; Roger Carlini; Robert Carr; Nicholas Chant; Yu-Chiu Chao; Swapan Chattopadhyay; Russell Clark; Silviu Covrig; Anthony Cowley; Daniel Dale; Charles Davis; Willie Falk; John Finn; Tony Forest; Gregg Franklin; Christophe Furget; David Gaskell; Joseph Grames; Keith Griffioen; Klaus Grimm; Benoit Guillon; Hayko Guler; Lars Hannelius; Richard HASTY; Alice Hawthorne Allen; Tanja Horn; Kathleen Johnston; Mark Jones; Peter Kammel; Reza Kazimi; Paul King; Ameya Kolarkar; Elie Korkmaz; Wolfgang Korsch; Serge Kox; Joachim Kuhn; Jeff Lachniet; Lawrence Lee; Jason Lenoble; Eric Liatard; Jianglai Liu; Berenice Loupias; Allison Lung; Dominique Marchand; Jeffery Martin; Kenneth McFarlane; David McKee; Robert McKeown; Fernand Merchez; Hamlet Mkrtchyan; Bryan Moffit; M. Morlet; Itaru Nakagawa; Kazutaka Nakahara; Retief Neveling; Silvia Niccolai; S. Ong; Shelley Page; Vassilios Papavassiliou; Stephen Pate; Sarah Phillips; Mark Pitt; Benard Poelker; Tracy Porcelli; Gilles Quemener; Brian Quinn; William Ramsay; Aamer Rauf; Jean-Sebastien Real; Julie Roche; Philip Roos; Gary Rutledge; Jeffery Secrest; Neven Simicevic; Gregory Smith; Damon Spayde; Samuel Stepanyan; Marcy Stutzman; Vince Sulkosky; Vincent Sulkosky; Vince Sulkosky; Vincent Sulkosky; Vardan Tadevosyan; Raphael Tieulent; Jacques Van de Wiele; Willem van Oers; Eric Voutier; William Vulcan; Glen Warren; Steven Wells; Steven Williamson; Stephen Wood; Chen Yan; Junho Yun; Valdis Zeps

    2007-08-01

    We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 values of 0.15 and 0.25 (GeV/c)^2 with results of A_n = -4.06 +- 0.99(stat) +- 0.63(syst) and A_n = -4.82 +- 1.87(stat) +- 0.98(syst) ppm. These results are inconsistent with calculations solely using the elastic nucleon intermediate state, and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A_n provides a direct probe of the imaginary component of the two-photon exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.

  13. Investigation of the nuclear matter distribution of 56Ni by elastic proton scattering in inverse kinematics

    NASA Astrophysics Data System (ADS)

    von Schmid, M.; Bagchi, S.; Bönig, S.; Csatlós, M.; Dillmann, I.; Dimopoulou, C.; Egelhof, P.; Eremin, V.; Furuno, T.; Geissel, H.; Gernhäuser, R.; Harakeh, M. N.; Hartig, A.-L.; Ilieva, S.; Kalantar-Nayestanaki, N.; Kiselev, O.; Kollmus, H.; Kozhuharov, C.; Krasznahorkay, A.; Kröll, T.; Kuilman, M.; Litvinov, S.; Litvinov, Yu A.; Mahjour-Shafiei, M.; Mutterer, M.; Nagae, D.; Najafi, M. A.; Nociforo, C.; Nolden, F.; Popp, U.; Rigollet, C.; Roy, S.; Scheidenberger, C.; Steck, M.; Streicher, B.; Stuhl, L.; Thürauf, M.; Uesaka, T.; Weick, H.; Winfield, J. S.; Winters, D.; Woods, P. J.; Yamaguchi, T.; Yue, K.; Zamora, J. C.; Zenihiro, J.; the EXL Collaboration

    2015-11-01

    We have measured the nuclear-matter distribution of the doubly-magic N = Z nucleus 56Ni by investigating elastic proton scattering in inverse kinematics. The radioactive beam of 56Ni was injected and stored in the experimental storage ring (ESR, GSI) and interacted with an internal hydrogen gas-jet target. The high revolution frequency of the ions in the ring enabled a high luminosity, despite the low density of the target being used. This way, measurements at very low momentum transfers became possible. By measuring the energy and the scattering angle of the recoiling protons, we were able to separate the elastic reaction channel from inelastic scattering to the first excited {2}+ state of 56Ni and deduced the differential cross section of 56Ni {(p,p)}56 Ni. The data were analyzed within the framework of the Glauber multiple-scattering theory in order to extract the nuclear-matter radius and radial matter distribution of 56Ni. Parameterizing the matter distribution with the phenomenological Symmetrized Fermi distribution, a preliminary value of 3.5 fm for the rms matter radius was deduced. This experiment was part of an EXL (EXotic nuclei studied in Light-ion induced reactions at storage rings) campaign at GSI in 2012 and was the first successful investigation of nuclear reactions with a stored radioactive beam ever.

  14. Fast proton hopping detection in ice I{sub h} by quasi-elastic neutron scattering.

    SciTech Connect

    Presiado, I.; Lal, J.; Mamontov, E.; Kolesnikov, A. I.; Huppert, D.

    2011-01-01

    Quasi-elastic neutron scattering was employed on samples of HCl-doped polycrystalline ice I{sub h}. The analysis of the scattering signal provides the excess proton hopping time, {tau}{sub hop}, in the temperature range of 140-195 K. The hopping time strongly depends on the temperature of the sample, and the activation energy of a hopping step is 17 kJ/mol. The values of {tau}{sub hop} of the current experiment are in good agreement with calculated values derived from previous photochemical experiments, in which we found that the proton hopping time at T > 242 K is on the order of 200 fs, roughly 10 times shorter than in liquid water at room temperature.

  15. Fast Proton Hopping Detection in Ice Ih by Quasi-Elastic Neutron Scattering

    SciTech Connect

    Presiado, Itay; Lal, Jyotsana; Mamontov, Eugene; Kolesnikov, Alexander I; Huppert, Dan I

    2011-01-01

    Quasi-elastic neutron scattering was employed on samples of HCl-doped polycrystalline ice I{sub h}. The analysis of the scattering signal provides the excess proton hopping time, {tau}{sub hop}, in the temperature range of 140-195 K. The hopping time strongly depends on the temperature of the sample, and the activation energy of a hopping step is 17 kJ/mol. The values of {tau}{sub hop} of the current experiment are in good agreement with calculated values derived from previous photochemical experiments,(1) in which we found that the proton hopping time at T > 242 K is on the order of 200 fs, roughly 10 times shorter than in liquid water at room temperature.

  16. Relativistic impulse approximation analysis of elastic proton scattering from He isotopes

    NASA Astrophysics Data System (ADS)

    Kaki, Kaori

    2014-01-01

    Recent relativistic mean field (RMF) calculations have provided nuclear distributions of some isotopes whose mass numbers are much larger than atomic numbers. For helium isotopes, the RMF calculation seems to be inappropriate because of the small mass numbers; however, applicable results are obtained for 6,8He nuclei. The author calculates observables of proton elastic scattering from the helium isotopes and discusses relations between observables and nuclear distributions of the isotopes by comparison of the calculated results with experimental data. The calculations are based on relativistic impulse approximation (RIA) at incident proton energy: 71 MeV for 4,6,8He, 300 and 500 MeV for 4He, and 0.7 GeV for 6He. Scattering observables are predicted for 6,8He at 200 MeV.

  17. Elastic scattering of polarized protons on helium three at 800 MeV

    SciTech Connect

    Azizi, A.

    1985-07-01

    A set of spin dependent parameters and cross sections has been measured for polarized p-/sup 3/He elastic scattering over the range of q .7 to 4.2 fm/sup -1/. The experiment was done at the Los Alamos Meson Physics Facility (LAMPF) using the High Resolution Spectrometer (HRS) with a polarized proton beam at .8 GeV. The focal plane polarimeter of the HRS was used to determine the spin direction of the scattered proton. Since /sup 3/He is one of the simplest nuclei, polarized p-/sup 3/He scattering provides a very sensitive test of multiple scattering theories. The theoretical analysis was done by using two different wave functions for /sup 3/He as input to the multiple scattering theory. The theoretical calculations and experimental data together will give us useful information about nucleon-nucleon amplitudes and also help us to obtain a better understanding of the scattering process. 68 refs., 55 figs., 9 tabs.

  18. Phenomenological optical potential analysis of proton-carbon elastic scattering at 200 MeV

    NASA Technical Reports Server (NTRS)

    Bidasaria, H. B.; Townsend, L. W.

    1982-01-01

    Differential cross sections for 200 MeV protons elastically scattered from C-12 were analyzed utilizing a local, complex, spin-dependent optical potential with a harmonic well radial dependence. Analyses were performed using the WKB and eikonal approximations. For the latter, first-order corrections to he phase shifts were incorporated to account for the spin-orbit contribution. Large disagreement between theory and experiment was observed when the usual Thomas form for the spin-orbit potential was utilized. Substantial improvement was obtained by allowing the parameters in the central and spin-orbit potential terms to vary independently.

  19. Investigation of the structure of light exotic nuclei by proton elastic scattering in inverse kinematics

    NASA Astrophysics Data System (ADS)

    Alkhazov, G. D.; Vorobyov, A. A.; Dobrovolsky, A. V.; Inglessi, A. G.; Korolev, G. A.; Khanzadeev, A. V.

    2015-05-01

    In order to study the spatial structure of exotic nuclei, it was proposed at the Petersburg Nuclear Physics Institute (PNPI) to measure the differential cross section for small-angle proton elastic scattering in inverse kinematics. Several experiments in beams of 0.7-GeV/nucleon exotic nuclei were performed at the heavy-ion accelerator facility of GSI (Gesellschaft für Schwerionenforschung, Darmstadt, Germany) by using the IKAR ionization spectrometer developed at PNPI. The IKAR ionization chamber filled with hydrogen at a pressure of 10 bar served simultaneously as a target and as a recoil-proton detector, which measured the recoil-proton energy. The beam-particle scattering angle was also measured. The results obtained for the cross sections in question were analyzed on the basis of the Glauber-Sitenko theory using phenomenological nuclear-density distributions with two free parameters. Nuclear-matter distributions and root-mean-square radii were found for the nuclei under investigation. The size of the halo in the 6He, 8He, 11Li, and 14Be nuclei was determined among other things. Information about neutron distributions in nuclei was deduced by combining the data obtained here with the known values of the radii of proton distributions. A sizable neutron skin was revealed in the 8Li, 9Li, and 12Be nuclei.

  20. Investigation of the structure of light exotic nuclei by proton elastic scattering in inverse kinematics

    SciTech Connect

    Alkhazov, G. D.; Vorobyov, A. A.; Dobrovolsky, A. V. Inglessi, A. G.; Korolev, G. A.; Khanzadeev, A. V.

    2015-05-15

    In order to study the spatial structure of exotic nuclei, it was proposed at the Petersburg Nuclear Physics Institute (PNPI) to measure the differential cross section for small-angle proton elastic scattering in inverse kinematics. Several experiments in beams of 0.7-GeV/nucleon exotic nuclei were performed at the heavy-ion accelerator facility of GSI (Gesellschaft für Schwerionenforschung, Darmstadt, Germany) by using the IKAR ionization spectrometer developed at PNPI. The IKAR ionization chamber filled with hydrogen at a pressure of 10 bar served simultaneously as a target and as a recoil-proton detector, which measured the recoil-proton energy. The beam-particle scattering angle was also measured. The results obtained for the cross sections in question were analyzed on the basis of the Glauber-Sitenko theory using phenomenological nuclear-density distributions with two free parameters. Nuclear-matter distributions and root-mean-square radii were found for the nuclei under investigation. The size of the halo in the {sup 6}He, {sup 8}He, {sup 11}Li, and {sup 14}Be nuclei was determined among other things. Information about neutron distributions in nuclei was deduced by combining the data obtained here with the known values of the radii of proton distributions. A sizable neutron skin was revealed in the {sup 8}Li, {sup 9}Li, and {sup 12}Be nuclei.

  1. Measurements of Proton-Proton and Proton-Antiproton Elastic Scattering at the European Center for Nuclear Research Intersecting Storage Rings.

    NASA Astrophysics Data System (ADS)

    Amos, Norman Alexander

    1985-12-01

    We have measured proton-proton and proton-antiproton elastic scattering at the CERN Intersecting Storage Rings. Using the optical theorem, we have extracted the total nuclear cross sections for these collisions. By measuring the interference between the Coulomb amplitude and the nuclear amplitude we have found (rho), the ratio of the real part to the imaginary part of the forward nuclear elastic scattering amplitude. Further, we have extracted the nuclear slope parameter in the forward direction. The elastic scattering measurements were made at small scattering angles ((TURN)1 milliradian), demanding that the detectors be placed close to the beams. Access to the interior of the ISR beam pipe was afforded by using reentrant cavities in the beam pipe, called "Roman Pots". The detectors consisted of two conjugate pairs of scintillator hodoscopes placed above and below the beams. Each detector consisted of a front plane of 24 strips of 2 mm scintillator which measured polar scattering angles, seven strips of 4 mm scintillator which measured azimuthal angles, and a trigger counter 48 x 28 mm('2). Normalization of the data was performed by two methods: (1) Van der Meer calibrations were performed on sets of luminosity monitor counters, (2) the known Coulomb differential scattering cross section fixed the normalization scale. For proton-proton interactions, the total nuclear cross sections measured were 39.95 (+OR-) 0.30 mb and 42.19 (+OR-) 0.19 mb for center-of-mass energies SQRT.(s) = 30.6 GeV and 52.8 GeV, respectively. The measured values of (rho) were 0.035 (+OR-) 0.009 and 0.071 (+OR-) 0.010. For proton-antiproton interactions, the cross sections found were 41.10 (+OR-) 0.40 mb and 43.34 (+OR-) 0.43 mb, respectively, and the (rho) values were 0.088 (+OR-) 0.025 and 0.066 (+OR-) 0.022.

  2. Measurement of the absolute differential cross section of proton–proton elastic scattering at small angles

    DOE PAGESBeta

    Mchedlishvili, D.; Chiladze, D.; Dymov, S.; Bagdasarian, Z.; Barsov, S.; Gebel, R.; Gou, B.; Hartmann, M.; Kacharava, A.; Keshelashvili, I.; et al

    2016-02-03

    The differential cross section for proton-proton elastic scattering has been measured at a beam kinetic energy of 1.0 GeV and in 200 MeV steps from 1.6 to 2.8 GeV for centre-of-mass angles in the range from 12°-16° to 25°-30°, depending on the energy. A precision in the overall normalisation of typically 3% was achieved by studying the energy losses of the circulating beam of the COSY storage ring as it passed repeatedly through the windowless hydrogen target of the ANKE magnetic spectrometer. It is shown that the data have a significant impact upon the results of a partial wave analysis.more » Furthermore, after extrapolating the differential cross sections to the forward direction, the results are broadly compatible with the predictions of forward dispersion relations.« less

  3. Nuclear Proton-proton Elastic Scattering via the Trojan Horse Method

    SciTech Connect

    Tumino, A.; Spitaleri, C.; Rapisarda, G. G.; Cherubini, S.; Crucilla, V.; Gulino, M.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Romano, S.; Sergi, M. L.; Mukhamedzhanov, A.; Campajola, L.; Elekes, Z.; Fueloep, Zs.; Gyuerky, G.; Kiss, G. G.; Somorjai, E.; Gialanella, L.

    2009-08-26

    We present here an important test of the main feature of the Trojan Horse Method (THM), namely the suppression of Coulomb effects in the entrance channel due to off-energy-shell effects. This is done by measuring the THM p--p elastic scattering via the p+d{yields}p+p+n reaction at 4.7 and 5 MeV, corresponding to a p--p relative energy ranging from 80 to 670 keV. In contrast to the on-energy-shell (OES) case, the extracted p-p cross section does not exhibit the Coulomb-nuclear interference minimum due to the suppression of the Coulomb amplitude. This is confirmed by the half-off-energy shell (HOES) calculations and strengthened by the agreement with the calculated OES nuclear cross sections.

  4. Proton-Nucleus Elastic Cross Sections Using Two-Body In-Medium Scattering Amplitudes

    NASA Technical Reports Server (NTRS)

    Tripathi, R. K.; Wilson, John W.; Cucinotta, Francis A.

    2001-01-01

    Recently, a method was developed of extracting nucleon-nucleon (NN) cross sections in the medium directly from experiment. The in-medium NN cross sections form the basic ingredients of several heavy-ion scattering approaches including the coupled-channel approach developed at the Langley Research Center. The ratio of the real to the imaginary part of the two-body scattering amplitude in the medium was investigated. These ratios are used in combination with the in-medium NN cross sections to calculate elastic proton-nucleus cross sections. The agreement is excellent with the available experimental data. These cross sections are needed for the radiation risk assessment of space missions.

  5. Virtual coupling potential for elastic scattering of 10,11Be on proton and carbon targets

    NASA Astrophysics Data System (ADS)

    Lapoux, V.; Alamanos, N.; Auger, F.; Blumenfeld, Y.; Casandjian, J.-M.; Chartier, M.; Cortina-Gil, M. D.; Fékou-Youmbi, V.; Gillibert, A.; Cormick, M. Mac; Maréchal, F.; Marie, F.; Mittig, W.; de Oliveira Santos, F.; Orr, N. A.; Ostrowski, A. N.; Ottini-Hustache, S.; Roussel-Chomaz, P.; Scarpaci, J.-A.; Sida, J.-L.; Suomijärvi, T.; Winfield, J. S.

    2008-01-01

    The 10,11Be(p, p) and (12C, 12C) reactions were analyzed to determine the influence of the weak binding energies of exotic nuclei on their interaction potential. The elastic cross sections were measured at GANIL in inverse kinematics using radioactive 10,11Be beams produced at energies of 39.1A and 38.4 A MeV. The elastic proton scattering data were analyzed within the framework of the microscopic Jeukenne-Lejeune-Mahaux (JLM) nucleon-nucleus potential. The angular distributions are found to be best reproduced by reducing the real part of the microscopic optical potential, as a consequence of the coupling to the continuum. These effects modify deeply the elastic potential. Including the Virtual Coupling Potential (VCP), we show the ability of the general optical potentials to reproduce the data for scattering of unstable nuclei, using realistic densities. Finally, the concepts needed to develop a more general and microscopic approach of the VCP are discussed.

  6. Measurements of proton-proton elastic scattering and total cross-section at the LHC by TOTEM

    NASA Astrophysics Data System (ADS)

    Deile, M.; Totem Collaboration

    2013-04-01

    The TOTEM experiment at the LHC has extended the measurement of the differential cross-section for elastic proton-proton scattering at √s = 7TeV to four-momentum transfers |t| as low as 5×10-3 GeV2. The new data were collected in different dedicated runs with a special beam optics (β* = 90m) and Roman Pot detectors placed as close as 4.8 times the transverse beam size from the outgoing beams. In addition, the accompanying inelastic rates were recorded with the forward telescopes T1 and T2 for 3.1 < |η| < 6.5. Thus the first measurement of the total protonproton cross-section with the luminosity-independent method based on the optical theorem could be performed. Alternatively, using the CMS luminosity measurement as an input, two additional total crosssection determinations with different systematic dependences were obtained: (a) as the direct sum of the elastic and inelastic cross-sections, and (b) calculated from only the elastic cross-section extrapolated to t = 0, as published previously [1] for an earlier data set. The results from all methods and data sets agree very well within their uncertainties.

  7. Measurements on Small Angle Elastic Scattering from Proton-Proton and Proton-Antiproton Collisions at the ISR.

    NASA Astrophysics Data System (ADS)

    Shukla, Shekhar

    Experiment R211 was performed at the Intersecting Storage Rings (ISR) of the European Center for Nuclear Research (CERN), Geneva, Switzerland. The aim was to measure, for pp and pp scattering at high energy, the three quantities: (1) the total nuclear cross section, (sigma)(,n), (2) the nuclear slope parameter, b, that describes the dependence of the differential elastic cross section on the 4-momentum transfer, t, for small (VBAR)t(VBAR), and (3) the ratio, (rho), of the real to the imaginary part of the forward nuclear elastic scattering amplitude. These quantities were deduced from differential elastic scattering cross sections measured in the near forward direction (down to (VBAR)t(VBAR) = .0003(GeV/c)('2) at SQRT.(s) = 23.5 GeV). The measurements were made for pp scattering at SQRT.(s) = 23.5 GeV, 30.5 GeV, 52.8 GeV and 62.5 GeV and pp scattering at SQRT.(s) = 30.5 GeV, 52.8 GeV and 62.5 GeV. The scattering was produced with two beams colliding at an angle of 14.7(DEGREES). Detectors consisting of strips of scintillators recorded the positions of the elastically scattered particles in the near forward direction. Another set of scintillation counters, calibrated using the van der Meer method, measured the luminosity. The optical theorem was used to obtain (sigma)(,n) from the differential cross section in the forward direction. Where available, the differential cross sections in the (VBAR)t(VBAR) range where the Coulomb and nuclear interaction were of comparable strength, served to determine the value of (rho). Again, if available, the measurements at higher values of (VBAR)t(VBAR), where the nuclear scattering dominated, were used to find the value of the slope parameter, b. The following quantities were measured: (i) (sigma)(,n) and (rho) at SQRT.(s) = 23.5 GeV and SQRT.(s) = 30.5 GeV, (ii) (sigma)(,n), (rho) and b at SQRT.(s) = 52.8 GeV and (iii) (sigma)(,n) and b at SQRT.(s) = 62.5 GeV. The total cross section for both pp and pp scattering is seen to rise

  8. Elastic scattering and breakup of 11Be on protons at 26.9 A MeV

    NASA Astrophysics Data System (ADS)

    Chen, J.; Lou, J. L.; Ye, Y. L.; Li, Z. H.; Ge, Y. C.; Li, Q. T.; Li, J.; Jiang, W.; Sun, Y. L.; Zang, H. L.; Aoi, N.; Ideguchi, E.; Ong, H. J.; Ayyad, Y.; Hatanaka, K.; Tran, D. T.; Yamamoto, T.; Tanaka, M.; Suzuki, T.; Tho, N. T.; Rangel, J.; Moro, A. M.; Pang, D. Y.; Lee, J.; Wu, J.; Liu, H. N.; Wen, C.

    2016-03-01

    The elastic scattering and breakup of the halo nucleus 11Be on protons at an incident energy of 26.9 A MeV have been measured. The 11Be+p elastic scattering cross sections at various energies, including the present one, are systematically analyzed with the Chapel Hill 89 (CH89) and Koning-Delaroche (KD) global optical model potentials (OMPs), and the corresponding normalization factors are obtained. An extended version of the continuum-discretized coupled-channels (XCDCC) formalism, including dynamic core excitation effects, is applied to analyze the elastic scattering and breakup data. It is found that the core excitation plays a moderate role in the elastic scattering and breakup reaction of the halo nucleus 11Be, being consistent with previous results at higher energies.

  9. Proton-proton elastic scattering at the LHC energy of \\chem{\\sqrt{s} = 7\\,TeV}

    NASA Astrophysics Data System (ADS)

    TOTEM Collaboration; Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bozzo, M.; Brücken, E.; Buzzo, A.; Cafagna, F. S.; Calicchio, M.; Catanesi, M. G.; Covault, C.; Csanád, M.; Csörgö, T.; Deile, M.; Dimovasili, E.; Doubek, M.; Eggert, K.; Eremin, V.; Ferro, F.; Fiergolski, A.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Janda, M.; Kašpar, J.; Kopal, J.; Kundrát, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Leszko, T.; Lippmaa, E.; Lokajíček, M.; Lo Vetere, M.; Rodríguez, F. Lucas; Macrí, M.; Magaletti, L.; Magazzù, G.; Mercadante, A.; Minutoli, S.; Nemes, F.; Niewiadomski, H.; Noschis, E.; Novák, T.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Österberg, K.; Perrot, A.-L.; Palazzi, P.; Pedreschi, E.; Petäjäjärvi, J.; Procházka, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Saarikko, H.; Santroni, A.; Scribano, A.; Sette, G.; Snoeys, W.; Spinella, F.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Vitek, M.; Welti, J.; Whitmore, J.

    2011-08-01

    Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at \\sqrt{s} = 7\\,TeV in dedicated runs with the Roman Pot detectors placed as close as seven times the transverse beam size (σbeam) from the outgoing beams. After careful study of the accelerator optics and the detector alignment, |t|, the square of four-momentum transferred in the elastic scattering process, has been determined with an uncertainty of \\delta t = 0.1\\,\\rm{GeV} \\sqrt{\\vert t\\vert } . In this letter, first results of the differential cross-section are presented covering a |t|-range from 0.36 to 2.5 GeV2. The differential cross-section in the range 0.36 < |t| < 0.47 GeV2 is described by an exponential with a slope parameter B = (23.6 ± 0.5stat ± 0.4syst) GeV-2, followed by a significant diffractive minimum at |t| = (0.53 ± 0.01stat ± 0.01syst) GeV2. For |t|-values larger than ~1.5 GeV2, the cross-section exhibits a power law behaviour with an exponent of -7.8 ± 0.3stat ± 0.1syst. When compared to predictions based on the different available models, the data show a strong discriminative power despite the small t-range covered.

  10. Condensate-enclosed chiral-bag model of the proton and pp elastic scattering at LHC 13 TeV

    NASA Astrophysics Data System (ADS)

    Islam, M. M.; Luddy, R. J.

    2015-11-01

    Our investigation of high energy pp and p¯p elastic scattering over the last ten years has led us to consider that the proton has three regions: (i) an outer region consisting of a quark-antiquark (qq¯) condensate ground state (also described as quark-antiquark outer cloud), (ii) an inner shell of topological (geometrical) baryonic charge of size ˜ 0.44 fm, and (iii) a core of size ˜ 0.2 fm, where the three valence quarks of a proton with baryonic charges are confined. The proton structure that has emerged leads to four main elastic scattering processes in pp scattering. The first process (which gives rise to diffraction scattering) is described by a profile function. The second process involves multiple ω-exchanges. The third process in pp scattering is quark-quark scattering via gluon-gluon interaction. The fourth process — which appears for the first time in our investigation of pp scattering — is a glancing collision at the boundary of a proton with that of the other proton. To describe quantitatively the four processes, their parameters have to be determined. For this purpose, we investigate: (i) pp 7 TeV dσ/dt measured by the TOTEM Collaboration and (ii) p¯p 1.96 TeV dσ/dt measured by the D0 Collaboration. Once the parameters are satisfactorily obtained, we calculate pp dσ/dt at 7 TeV and compare with the TOTEM data. We also calculate p¯p dσ/dt at 1.96 TeV and compare with the D0 data. We then predict pp elastic dσ/dt at 13 TeV which will soon be measured at LHC by the TOTEM Collaboration. This measurement will establish how well we have predicted the 13 TeV dσ/dt and determined the structure of the proton.

  11. Transverse Beam Spin Asymmetries at Backward Angles in Elastic Electron-Proton and Quasielastic Electron-Deuteron Scattering

    NASA Astrophysics Data System (ADS)

    Androić, D.; Armstrong, D. S.; Arvieux, J.; Bailey, S. L.; Beck, D. H.; Beise, E. J.; Benesch, J.; Benmokhtar, F.; Bimbot, L.; Birchall, J.; Bosted, P.; Breuer, H.; Capuano, C. L.; Chao, Y.-C.; Coppens, A.; Davis, C. A.; Ellis, C.; Flores, G.; Franklin, G.; Furget, C.; Gaskell, D.; Gericke, M. T. W.; Grames, J.; Guillard, G.; Hansknecht, J.; Horn, T.; Jones, M. K.; King, P. M.; Korsch, W.; Kox, S.; Lee, L.; Liu, J.; Lung, A.; Mammei, J.; Martin, J. W.; McKeown, R. D.; Micherdzinska, A.; Mihovilovic, M.; Mkrtchyan, H.; Muether, M.; Page, S. A.; Papavassiliou, V.; Pate, S. F.; Phillips, S. K.; Pillot, P.; Pitt, M. L.; Poelker, M.; Quinn, B.; Ramsay, W. D.; Real, J.-S.; Roche, J.; Roos, P.; Schaub, J.; Seva, T.; Simicevic, N.; Smith, G. R.; Spayde, D. T.; Stutzman, M.; Suleiman, R.; Tadevosyan, V.; van Oers, W. T. H.; Versteegen, M.; Voutier, E.; Vulcan, W.; Wells, S. P.; Williamson, S. E.; Wood, S. A.; Pasquini, B.; Vanderhaeghen, M.

    2011-07-01

    We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasielastic scattering on the deuteron, at backward angles (lab scattering angle of 108°) for Q2=0.22GeV2/c2 and 0.63GeV2/c2 at beam energies of 362 and 687 MeV, respectively. The asymmetry arises due to the imaginary part of the interference of the two-photon exchange amplitude with that of single-photon exchange. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (πN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasistatic deuterium approximation, and is also in agreement with theory.

  12. Transverse beam spin asymmetries at backward angles in elastic electron-proton and quasielastic electron-deuteron scattering.

    PubMed

    Androić, D; Armstrong, D S; Arvieux, J; Bailey, S L; Beck, D H; Beise, E J; Benesch, J; Benmokhtar, F; Bimbot, L; Birchall, J; Bosted, P; Breuer, H; Capuano, C L; Chao, Y-C; Coppens, A; Davis, C A; Ellis, C; Flores, G; Franklin, G; Furget, C; Gaskell, D; Gericke, M T W; Grames, J; Guillard, G; Hansknecht, J; Horn, T; Jones, M K; King, P M; Korsch, W; Kox, S; Lee, L; Liu, J; Lung, A; Mammei, J; Martin, J W; McKeown, R D; Micherdzinska, A; Mihovilovic, M; Mkrtchyan, H; Muether, M; Page, S A; Papavassiliou, V; Pate, S F; Phillips, S K; Pillot, P; Pitt, M L; Poelker, M; Quinn, B; Ramsay, W D; Real, J-S; Roche, J; Roos, P; Schaub, J; Seva, T; Simicevic, N; Smith, G R; Spayde, D T; Stutzman, M; Suleiman, R; Tadevosyan, V; van Oers, W T H; Versteegen, M; Voutier, E; Vulcan, W; Wells, S P; Williamson, S E; Wood, S A; Pasquini, B; Vanderhaeghen, M

    2011-07-01

    We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasielastic scattering on the deuteron, at backward angles (lab scattering angle of 108°) for Q² = 0.22 GeV²/c² and 0.63 GeV²/c² at beam energies of 362 and 687 MeV, respectively. The asymmetry arises due to the imaginary part of the interference of the two-photon exchange amplitude with that of single-photon exchange. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (πN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasistatic deuterium approximation, and is also in agreement with theory. PMID:21797598

  13. Measurements of sin/sup 2/ theta/sub w/ from studies of the elastic scattering of neutrinos by protons and electrons

    SciTech Connect

    Mann, A.K.

    1986-01-01

    This talk is intended as a brief report on studies of the elastic scattering of neutrinos by protons and electrons. Measurements of the ratios of muon antineutrino and muon neutrino elastic scattering on protons, and the corresponding ratio for elastic scattering on electrons minimize systematic experimental errors, and lead directly to values of the fundamental parameter of the electroweak interaction, the Weinberg Angle, with minimal ambiguity. Accordingly, the principal motivation in carrying out these studies was the desire to obtain and compare precise values of the Weinberg Angle from both the semileptonic and leptonic reactions as still another test of the basic validity of the standard electroweak theory. 10 refs., 11 figs.

  14. Structure of low-lying states of {sup 10,11}C from proton elastic and inelastic scattering

    SciTech Connect

    Jouanne, C.; Lapoux, V.; Auger, F.; Alamanos, N.; Drouart, A.; Gillibert, A.; Lobo, G.; Musumarra, A.; Nalpas, L.; Pollacco, E.; Sida, J.-L.; Trotta, M.; Blumenfeld, Y.; Khan, E.; Suomijaervi, T.; Zerguerras, T.; Roussel-Chomaz, P.; Savajols, H.; Lagoyannis, A.; Pakou, A.

    2005-07-01

    To probe the ground state and transition densities, elastic and inelastic scattering on a proton target were measured in inverse kinematics for the unstable {sup 10}C and {sup 11}C nuclei at 45.3 and 40.6 MeV/nucleon, respectively. The detection of the recoil proton was performed by the MUST telescope array, in coincidence with a wall of scintillators for the quasiprojectile. The differential cross sections for elastic and inelastic scattering to the first excited states are compared to the optical model calculations performed within the framework of the microscopic nucleon-nucleus Jeukenne-Lejeune-Mahaux potential. Elastic scattering is sensitive to the matter-root-mean square radius found to be 2.42{+-}0.1 and 2.33{+-}0.1 fm, for {sup 10,11}C, respectively. The transition densities from cluster and mean-field models are tested, and the cluster model predicts the correct order of magnitude of cross sections for the transitions of both isotopes. Using the Bohr-Mottelson prescription, a profile for the {sup 10}C transition density from the 0{sup +} ground to the 2{sub 1}{sup +} state is deduced from the data. The corresponding neutron transition matrix element is extracted: M{sub n}=5.51{+-}1.09 fm{sup 2}.

  15. Meson exchange effects in elastic ep scattering at loop level and the electromagnetic form factors of the proton

    NASA Astrophysics Data System (ADS)

    Chen, Hong-Yu; Zhou, Hai-Qing

    2014-10-01

    A new form of two-photon exchange (TPE) effect is studied to explain the discrepancy between unpolarized and polarized experimental data in elastic ep scattering. The mechanism is based on a simple idea that apart from the usual TPE effects from box and crossed-box diagrams, the mesons may also be exchanged in elastic ep scattering by two-photon coupling at loop level. The detailed study shows such contributions to reduced unpolarized cross section (σun) and polarized observables (Pt,Pl) at fixed Q2 are only dependent on proton's electromagnetic form factors GE ,M and a new unknown universal parameter g. After combining this contribution with the usual TPE contributions from box and crossed-box diagrams, the ratio μpGE/GM extracted from the recent precise unpolarized and polarized experimental data can be described consistently.

  16. Two-Photon-Exchange and {gamma}Z-Exchange Corrections to Parity-Violating Elastic Electron-Proton Scattering

    SciTech Connect

    Zhou Haiqing; Kao Chungwen; Yang Shinnan

    2007-12-31

    Leading electroweak corrections play an important role in precision measurements of the strange form factors. We calculate the two-photon-exchange (TPE) and {gamma}Z-exchange corrections to the parity-violating asymmetry of the elastic electron-proton scattering in a simple hadronic model including the finite size of the proton. We find both can reach a few percent and are comparable in size with the current experimental measurements of strange-quark effects in the proton neutral weak current. The effect of {gamma}Z exchange is in general larger than that of TPE, especially at low momentum transfer Q{sup 2}{<=}1 GeV{sup 2}. Their combined effects on the values of G{sub E}{sup s}+G{sub M}{sup s} extracted in recent experiments can be as large as -40% in certain kinematics.

  17. Measurement of analyzing power for proton-carbon elastic scattering in the coulomb-nuclear interference region with a 22-GeV/c polarized proton beam.

    PubMed

    Tojo, J; Alekseev, I; Bai, M; Bassalleck, B; Bunce, G; Deshpande, A; Doskow, J; Eilerts, S; Fields, D E; Goto, Y; Huang, H; Hughes, V; Imai, K; Ishihara, M; Kanavets, V; Kurita, K; Kwiatkowski, K; Lewis, B; Lozowski, W; Makdisi, Y; Meyer, H-O; Morozov, B V; Nakamura, M; Przewoski, B; Rinckel, T; Roser, T; Rusek, A; Saito, N; Smith, B; Svirida, D; Syphers, M; Taketani, A; Thomas, T L; Underwood, D; Wolfe, D; Yamamoto, K; Zhu, L

    2002-07-29

    The analyzing power for proton-carbon elastic scattering in the Coulomb-nuclear interference region of momentum transfer, 9.0x10(-3)<-t<4.1x10(-2) (GeV/c)(2), was measured with a 21.7 GeV/c polarized proton beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory. The ratio of hadronic spin-flip to nonflip amplitude, r(5), was obtained from the analyzing power to be Rer(5)=0.088+/-0.058 and Imr(5)=-0.161+/-0.226. PMID:12144435

  18. Monte Carlo simulation and parameterized treatment on the effect of nuclear elastic scattering in high-energy proton radiography

    NASA Astrophysics Data System (ADS)

    Xu, Hai-Bo; Zheng, Na

    2015-07-01

    A version of Geant4 has been developed to treat high-energy proton radiography. This article presents the results of calculations simulating the effects of nuclear elastic scattering for various test step wedges. Comparisons with experimental data are also presented. The traditional expressions of the transmission should be correct if the angle distribution of the scattering is Gaussian multiple Coulomb scattering. The mean free path (which depends on the collimator angle) and the radiation length are treated as empirical parameters, according to transmission as a function of thickness obtained by simulations. The results can be used in density reconstruction, which depends on the transmission expressions. Supported by NSAF (11176001) and Science and Technology Developing Foundation of China Academy of Engineering Physics (2012A0202006)

  19. Role of elastic projectile-electron scattering in double ionization of helium by fast proton impact

    NASA Astrophysics Data System (ADS)

    Schulz, M.; Ciappina, M. F.; Kirchner, T.; Fischer, D.; Moshammer, R.; Ullrich, J.

    2009-04-01

    We present a systematic study of atomic four-body fragmentation dynamics. To this end we have measured a variety of multiple differential double ionization cross sections for 6 MeV p+He collisions. The data are compared to a first-order calculation with correlated electrons and to a simulation representing a second-order process, with some experimental results seemingly in favor of the first, others in agreement with the second approach. This apparent conflict can be resolved by accounting for elastic scattering between the projectile and one electron already promoted to the continuum through electron-electron correlation in the first-order process.

  20. Validity of the relativistic impulse approximation for elastic proton-nucleus scattering at energies lower than 200 MeV

    SciTech Connect

    Li, Z. P.; Hillhouse, G. C.; Meng, J.

    2008-07-15

    We present the first study to examine the validity of the relativistic impulse approximation (RIA) for describing elastic proton-nucleus scattering at incident laboratory kinetic energies lower than 200 MeV. For simplicity we choose a {sup 208}Pb target, which is a spin-saturated spherical nucleus for which reliable nuclear structure models exist. Microscopic scalar and vector optical potentials are generated by folding invariant scalar and vector scattering nucleon-nucleon (NN) amplitudes, based on our recently developed relativistic meson-exchange model, with Lorentz scalar and vector densities resulting from the accurately calibrated PK1 relativistic mean field model of nuclear structure. It is seen that phenomenological Pauli blocking (PB) effects and density-dependent corrections to {sigma}N and {omega}N meson-nucleon coupling constants modify the RIA microscopic scalar and vector optical potentials so as to provide a consistent and quantitative description of all elastic scattering observables, namely, total reaction cross sections, differential cross sections, analyzing powers and spin rotation functions. In particular, the effect of PB becomes more significant at energies lower than 200 MeV, whereas phenomenological density-dependent corrections to the NN interaction also play an increasingly important role at energies lower than 100 MeV.

  1. Elastic proton scattering at intermediate energies as a probe of the He,86 nuclear matter densities

    NASA Astrophysics Data System (ADS)

    Chung, Le Xuan; Kiselev, Oleg A.; Khoa, Dao T.; Egelhof, Peter

    2015-09-01

    The Glauber model analysis of the elastic He,86+p scattering data at energies around 700 MeV/nucleon, measured in two separate experiments at GSI-Darmstadt, has been carried out using several phenomenological parametrizations of the nuclear matter density. By taking into account the new data points measured at high-momentum transfer, the nuclear matter radii of ,8He6 have been accurately determined from the Glauber model analysis of the data, with the spin-orbital interaction explicitly taken into account. The well-known geometry for the core and dineutron halo has been used with the new parametrizations of the 6He density to extract the detailed information on the structure of 6He in terms of the core and dineutron halo radii. An enhanced sensitivity of the data measured at high-momentum transfer to the core part of the 6,8He densities has been found.

  2. Direct measurements of two photon exchange on lepton-proton elastic scattering using simultaneous electron-positron beams in CLAS

    NASA Astrophysics Data System (ADS)

    Adikaram, Dasuni Kalhari

    The electric (GE) and magnetic ( GM) form factors of the proton are fundamental observables which characterize its charge and magnetization distributions. There are two methods to measure the proton form factors: the Rosenbluth separation method and the polarization transfer technique. However, the ratio of the electric and magnetic form factors measured by those methods significantly disagree at momentum transfer Q2 > 1 GeV2. The most likely explanation of this discrepancy is the inclusion of two-photon exchange (TPE) amplitude contributions to the elastic electron-proton cross section which significantly changes the extraction of GE from the Rosenbluth separation measurement. The Jefferson Lab CLAS TPE experiment determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections. The primary electron beam was used to create an intense bremsstrahlung photon beam. Some of the photons were then converted to a mixed e+/ e- beam which then interacted with a liquid hydrogen target. The e+p and e-p events were detected by the CLAS (CEBAF Large Acceptance Spectrometer). The elastic cross section ratios ((sigma( e+p)/(sigma(e -p)) were measured over a wide range of virtual photon polarization epsilon and Q2. The cross section ratios displayed a strong epsilon dependence at Q2 = 1.45 GeV2. There is no significant Q2 dependence observed at epsilon = 0.45. The results are consistent with a recent measurement at the VEPP-3 lepton storage ring in Novosibirsk and with the hadronic calculation by Blunders, Melnitchouk and Tjon. The hadronic calculation resolves the disagreement between the Rosenbluth separation and polarization transfer extractions of GE/GM at Q2 up to 2 -- 3 GeV2. Applying the GLAS TPE correction to the Rosenbluth cross section measurements significantly decreases the extracted value of GE and brings it into good agreement with the polarization transfer measurement at Q2˜1.75 GeV2. Thus, these

  3. New Measurement of Parity Violation in Elastic Electron-Proton Scattering and Implications for Strange Form Factors

    SciTech Connect

    Konrad Aniol; David Armstrong; Todd Averett; Maud Baylac; Etienne Burtin; John Calarco; Gordon Cates; Christian Cavata; Zhengwei Chai; C. Chang; Jian-Ping Chen; Eugene Chudakov; Evaristo Cisbani; Marius Coman; Daniel Dale; Alexandre Deur; Pibero Djawotho; Martin Epstein; Stephanie Escoffier; Lars Ewell; Nicolas Falletto; John Finn; A. Fleck; Bernard Frois; Salvatore Frullani; Juncai Gao; Franco Garibaldi; Ashot Gasparian; G. M. Gerstner; Ronald Gilman; Oleksandr Glamazdin; Javier Gomez; Viktor Gorbenko; Jens-ole Hansen; F. Hersman; Douglas Higinbotham; Richard Holmes; Maurik Holtrop; Thomas Humensky; Sebastien Incerti; Mauro Iodice; Cornelis De Jager; Johann Jardillier; Xiaodong Jiang; Mark Jones; J. Jorda; Christophe Jutier; W. Kahl; James Kelly; Donghee Kim; M. -J. Kim; Minsuk Kim; Ioannis Kominis; Edgar Kooijman; Kevin Kramer; Krishna Kumar; Michael Kuss; John LeRose; Raffaele De Leo; M. Leuschner; David Lhuillier; Meihua Liang; Nilanga Liyanage; R. Lourie; Richard Madey; Sergey Malov; Demetrius Margaziotis; Frederic Marie; Pete Markowitz; Jacques Martino; Peter Mastromarino; Kathy McCormick; Justin McIntyre; Zein-Eddine Meziani; Robert Michaels; Brian Milbrath; Gerald Miller; Joseph Mitchell; Ludyvine Morand; Damien Neyret; Gerassimos Petratos; Roman Pomatsalyuk; John Price; David Prout; Thierry Pussieux; Gilles Quemener; Ronald Ransome; David Relyea; Yves Roblin; Julie Roche; Gary Rutledge; Paul Rutt; Marat Rvachev; Franck Sabatie; Arunava Saha; Paul Souder; Marcus Spradlin; Steffen Strauch; Riad Suleiman; Jeffrey Templon; T. Teresawa; James Thompson; Raphael Tieulent; Luminita Todor; Baris Tonguc; Paul Ulmer; Guido Urciuoli; Branislav Vlahovic; Krishni Wijesooriya; R. Wilson; Bogdan Wojtsekhowski; Rhett Woo; Wang Xu; Imran Younus; C. Zhang

    2001-06-01

    We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The result is A = -15.05 +- 0.98(stat) {+-} 0.56(syst) ppm at the kinematic point theta{sub lab} = 12.3 degrees and Q{sup 2} = 0.477 (GeV/c){sup 2}. The measurement implies that the value for the strange form factor (G{sub E}{sup s} + 0.392 G{sub M}{sup s})/(G{sub M}{sup p} {mu}{sub p}) = 0.069 +- 0.056 +- 0.039, where the first error is experimental and the second arises from the uncertainties in electromagnetic form factors. This measurement is the first fixed-target parity violation experiment that used either a ''strained'' GaAs photocathode to produce highly polarized electrons or a Compton polarimeter to continuously monitor the electron beam polarization.

  4. Study of proton resonance structure in 27P via resonant elastic scattering of 26Si+p

    NASA Astrophysics Data System (ADS)

    Jung, H. S.; Lee, C. S.; Kwon, Y. K.; Moon, J. Y.; Lee, J. H.; Yun, C. C.; Kubono, S.; Yamaguchi, H.; Hashimoto, T.; Kahl, D.; Hayakawa, S.; Choi, Seonho; Kim, M. J.; Kim, Y. H.; Kim, Y. K.; Park, J. S.; Kim, E. J.; Moon, C.-B.; Teranishi, T.; Wakabayashi, Y.; Iwasa, N.; Yamada, T.; Togano, Y.; Kato, S.; Cherubini, S.; Rapisarda, G. G.

    2012-11-01

    A measurement of resonant elastic scattering of 26Si+p was performed with a thick target using a 26Si radioactive ion beam at the CRIB (CNS Radioactive Ion Beam separator) of the Center for Nuclear Study (CNS), the University of Tokyo. The excitation function of 27P was measured successfully with the inverse kinematics method through a covered the range of excitation energies from Ex ~ 2.3 to 3.8 MeV, providing information about the resonance structure of this nucleus. The properties of these resonances are important to better determine the production rates of 26Si(p,g)27P reaction, which is one of the astrophysically important nuclear reactions to understand the production of the 26Al. Some new resonant states have been investigated, and determined their resonance parameters, such as excitation energies, proton partial widths, and spin-parities by R-matrix calculation.

  5. Test of charge symmetry in neutron-proton elastic scattering at 477 MeV

    SciTech Connect

    Abegg, R.; Bandyopadhyay, D.; Birchall, J.; Cairns, E.W.; Coombes, H.; Davis, C.A.; Davison, N.E.; Delheij, P.P.J.; Green, P.W.; Greeniaus, L.G.; Gubler, H.P.; Healy, D.C.; Lapointe, C.; Lee, W.P.; McDonald, W.J.; Miller, C.A.; Moss, G.A.; Plattner, G.R.; Poffenberger, P.R.; Ramsay, W.D.; Roy, G.; Soukup, J.; Svenne, J.P.; Tkachuk, R.; van Oers, W.T.H.; Wait, G.D.; Zhang, Y.P.

    1986-06-16

    An experiment resulting in the first measurement of the isospin-mixing, charge-symmetry violating component of the n-italic-p-italic interaction has been performed. The experiment determined the difference in the angles of the zero crossing of the neutron and proton analyzing powers A-italic/sub n-italic/ and A-italic/sub p-italic/ at 477 MeV. In terms of the laboratory scattering angle of the neutron, the measured difference t-italich-italice-italict-italica-italic/sub 0//sub n-italic/(A/sub n/)= -t-italich-italice-italict-italica-italic/sub 0//sub n-italic/(A/sub p/) = +0.13X(de +- 0.06 X(de( +- 0.03X(de) where the second error is a worst case estimate of systematic error. The resulting difference in the analyzing powers at the zero-crossing angle A-italic/sub n-italic/-A/sub p/ = +0.0037 +- 0.0017( +- 0 .0008).

  6. Measurement of proton-proton elastic scattering and total cross-section at \\chem{\\sqrt {s} = 7\\,TeV}

    NASA Astrophysics Data System (ADS)

    The TOTEM Collaboration; Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bossini, E.; Bozzo, M.; Brogi, P.; Brücken, E.; Buzzo, A.; Cafagna, F. S.; Calicchio, M.; Catanesi, M. G.; Covault, C.; Csanád, M.; Csörgő, T.; Deile, M.; Eggert, K.; Eremin, V.; Ferretti, R.; Ferro, F.; Fiergolski, A.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Intonti, R. A.; Kašpar, J.; Kopal, J.; Kundrát, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Leszko, T.; Lippmaa, E.; Lokajíček, M.; Lo Vetere, M.; Rodríguez, F. Lucas; Macrí, M.; Mäki, T.; Mercadante, A.; Minafra, N.; Minutoli, S.; Nemes, F.; Niewiadomski, H.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Österberg, K.; Palazzi, P.; Procházka, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Saarikko, H.; Santroni, A.; Scribano, A.; Smajek, J.; Snoeys, W.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Vítek, M.; Welti, J.; Whitmore, J.

    2013-01-01

    At the LHC energy of \\sqrt s = 7\\,{ { TeV}} , under various beam and background conditions, luminosities, and Roman Pot positions, TOTEM has measured the differential cross-section for proton-proton elastic scattering as a function of the four-momentum transfer squared t. The results of the different analyses are in excellent agreement demonstrating no sizeable dependence on the beam conditions. Due to the very close approach of the Roman Pot detectors to the beam center (≈5σbeam) in a dedicated run with β* = 90 m, |t|-values down to 5·10-3 GeV2 were reached. The exponential slope of the differential elastic cross-section in this newly explored |t|-region remained unchanged and thus an exponential fit with only one constant B = (19.9 ± 0.3) GeV-2 over the large |t|-range from 0.005 to 0.2 GeV2 describes the differential distribution well. The high precision of the measurement and the large fit range lead to an error on the slope parameter B which is remarkably small compared to previous experiments. It allows a precise extrapolation over the non-visible cross-section (only 9%) to t = 0. With the luminosity from CMS, the elastic cross-section was determined to be (25.4 ± 1.1) mb, and using in addition the optical theorem, the total pp cross-section was derived to be (98.6 ± 2.2) mb. For model comparisons the t-distributions are tabulated including the large |t|-range of the previous measurement (TOTEM Collaboration (Antchev G. et al), EPL, 95 (2011) 41001).

  7. ELASTIC SCATTERING OF PROTONS FROM $\\sqrt{s} = 23.5~{\\rm GeV}$ to 7 TeV FROM A GENERALIZED BIALAS-BZDAK MODEL

    NASA Astrophysics Data System (ADS)

    Csörgő, T.; Nemes, F.

    2014-01-01

    The Bialas-Bzdak model of elastic proton-proton scattering is generalized to the case when the real part of the parton-parton level forward scattering amplitude is nonvanishing. Such a generalization enables the model to describe well the dip region of the differential cross-section of elastic scattering at the intersecting storage rings (ISR) energies, and improves significantly the ability of the model to describe also the recent TOTEM data at √ {s} = 7 TeV LHC energy. Within this framework, both the increase of the total cross-section, as well as the decrease of the location of the dip with increasing colliding energies, is related to the increase of the quark-diquark distance and to the increase of the "fragility" of the protons with increasing energies. In addition, we present and test the validity of two new phenomenological relations: one of them relates the total p+p cross-section to an effective, model-independent proton radius, while the other relates the position of the dip in the differential elastic cross-section to the measured value of the total cross-section.

  8. Study of proton resonance structure in {sup 27}P via resonant elastic scattering of {sup 26}Si+p

    SciTech Connect

    Jung, H. S.; Lee, C. S.; Kwon, Y. K.; Moon, J. Y.; Lee, J. H.; Yun, C. C.; Kubono, S.; Yamaguchi, H.; Hashimoto, T.; Kahl, D.; Hayakawa, S.; Choi, Seonho; Kim, M. J.; Kim, Y. H.; Kim, Y. K.; Park, J. S.; Kim, E. J.; Moon, C.-B.; Teranishi, T.; Wakabayashi, Y.; and others

    2012-11-12

    A measurement of resonant elastic scattering of {sup 26}Si+p was performed with a thick target using a {sup 26}Si radioactive ion beam at the CRIB (CNS Radioactive Ion Beam separator) of the Center for Nuclear Study (CNS), the University of Tokyo. The excitation function of {sup 27}P was measured successfully with the inverse kinematics method through a covered the range of excitation energies from E{sub x}{approx} 2.3 to 3.8 MeV, providing information about the resonance structure of this nucleus. The properties of these resonances are important to better determine the production rates of {sup 26}Si(p,g){sup 27}P reaction, which is one of the astrophysically important nuclear reactions to understand the production of the {sup 26}Al. Some new resonant states have been investigated, and determined their resonance parameters, such as excitation energies, proton partial widths, and spin-parities by R-matrix calculation.

  9. Contribution of two-boson exchange with {delta}(1232) excitation to parity-violating elastic electron-proton scattering

    SciTech Connect

    Nagata, Keitaro; Kao, C. W.; Zhou Haiqing; Yang Shinnan

    2009-06-15

    We study the leading electroweak corrections in the precision measurement of the strange form factors. Specifically, we calculate the two-boson exchange (TBE), two-photon exchange (TPE) plus {gamma}Z exchange ({gamma}ZE), and corrections with {delta}(1232) excitation to the parity-violating asymmetry of the elastic electron-proton scattering. The interplay between nucleon and {delta} contributions is found to depend strongly on the kinematics, as {delta}{sub {delta}} begins as negligible at backward angles but becomes very large and negative and dominant at forward angles, while {delta}{sub N} always stays positive and decreases monotonically with increasing {epsilon}. The total TBE corrections to the extracted values of G{sub E}{sup s}+{beta}G{sub M}{sup s} in recent experiments of HAPPEX and G0 are, depending on kinematics, found to be large and range between 13% and -75%, but are found to be small in the case of A4 experiments.

  10. Parity violation in the elastic scattering from the proton in Hall A

    SciTech Connect

    Souder, Paul

    1992-06-01

    We are planning to measure the parity-violating electroweak asymmetry in the scattering of polarized electrons from hydrogen. We expect to obtain unique information about the weak form factors of the nucleon emphasizing the possible contributions of strange quarks to the weak vector matrix elements involved. Helium and deuterium and other possible targets of interest.

  11. Two-Photon Exchange Effects in Elastic Electron-Proton Scattering

    SciTech Connect

    Johnson, Myriam James

    2013-08-01

    Two methods, Rosenbluth separation and polarization transfer, can be used to extract the proton form factor ratio μp GEp/GMp, but they do not yield the same results. It is thought that the disagreement is due to two photon exchange corrections to the differential cross sections. High precision proton Rosenbluth extractions were carried out at 102 kinematics points spanning 16 values of momentum transfer Q2, from 0.40 to 5.76 GeV2. Reduced cross sections were found to 1.1% or better for Q2 less than 3 GeV2 increasing to 4% at 5.76 GeV2 The form factor ratios were determined to 1:5-3% for Q2 < 1.5 GeV2, increasing to 9% by 3 GeV2 and rapidly above. Our data agrees with prior Rosenbluth, improving upon it the 1.0 - 2.0 GeV2 range to conclusively show a separation from polarization transfer where it had not been certain before. In addition, reduced cross sections at each Q2 were tested for nonlinearity in the angular variable. Such a departure from linearity would be a signature of two photon exchange effects, and prior data had not been sufficiently precise to show nonzero curvature. Our data begins to hint at negative curvature but does not yet show a significant departure from zero.

  12. HZETRN: neutron and proton production in quasi-elastic scattering of GCR heavy-ions

    NASA Technical Reports Server (NTRS)

    Shavers, M. R.; Cucinotta, F. A.; Wilson, J. W.

    2001-01-01

    The development of transport models for radiation shielding design and evaluation has provided a series of deterministic computer codes that describe galactic cosmic radiation (GCR), solar particle events, and experimental beams at particle accelerators. These codes continue to be modified to accommodate new theory and improvements to the particle interaction database (Cucinotta et al., 1994, NASA Technical Paper 3472, US Government Printing Office, Washington DC). The solution employed by the heavy-ion transport code HZETRN was derived with the assumption that nuclear fragments are emitted with the same velocity as the incident ion through velocity conserving nuclear interactions. This paper presents a version of the HZETRN transport code that provides a more realistic distribution of the energy of protons and neutrons emitted from GCR interactions in shields. This study shows that the expected GCR dose equivalent is lower than previously calculated for water shields that are less than 110 g cm-2 thick. Calculations of neutron energy spectra in low Earth orbit indicate substantial contributions from relativistic neutrons. c2001 Elsevier Science Ltd. All rights reseved.

  13. K-shell ionization probability in elastic proton scattering on /sup 138/Ba through an f/sub 7/2/ isobaric-analog resonance

    SciTech Connect

    Dost, M.; Lorek, R.; Roehl, S.; Seidel, J.; Koenig, W.

    1985-10-01

    The bombarding energy dependence of the K-shell ionization probability P/sub K/ was measured in elastic proton scattering on /sup 138/Ba at energies near the 69-keV-wide f/sub 7/2/ isobaric-analog resonance at 9.965 MeV. The best simultaneous fit to P/sub K/ in the scattering angle intervals 45/sup 0/--80/sup 0/ and 100/sup 0/--135/sup 0/ yields R/sub 0/ = -0.30 +- 0.30 for the tangent of the phase angle of the semiclassical monopole ionization amplitude.

  14. A 3% Measurement of the Beam Normal Single Spin Asymmetry in Forward Angle Elastic Electron-Proton Scattering using the Qweak Setup

    SciTech Connect

    Waidyawansa, Dinayadura Buddhini

    2013-08-01

    The beam normal single spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable of the imaginary part of the two-photon exchange process. Moreover, it is a potential source of false asymmetry in parity violating electron scattering experiments. The Q{sub weak} experiment uses parity violating electron scattering to make a direct measurement of the weak charge of the proton. The targeted 4% measurement of the weak charge of the proton probes for parity violating new physics beyond the Standard Model. The beam normal single spin asymmetry at Q{sub weak} kinematics is at least three orders of magnitude larger than 5 ppb precision of the parity violating asymmetry. To better understand this parity conserving background, the Q{sub weak} Collaboration has performed elastic scattering measurements with fully transversely polarized electron beam on the proton and aluminum. This dissertation presents the analysis of the 3% measurement (1.3% statistical and 2.6% systematic) of beam normal single spin asymmetry in electronproton scattering at a Q2 of 0.025 (GeV/c)2. It is the most precise existing measurement of beam normal single spin asymmetry available at the time. A measurement of this precision helps to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process.

  15. Totem Results on Elastic Scattering and Total Cross-Section

    NASA Astrophysics Data System (ADS)

    Kašpar, Jan

    2015-06-01

    TOTEM is an LHC experiment dedicated to forward hadronic physics. In this contribution, an update on two main parts of its physics programme is given: proton-proton elastic scattering and total cross-section.

  16. Proton (antiproton) elastic scattering at energies from FNAL to the LHC in the tripole Pomeron-Odderon model

    NASA Astrophysics Data System (ADS)

    Martynov, E.

    2013-06-01

    The model of elastic scattering amplitudes dominated by the triple (at t=0) Pomeron pole suggested earlier is modified to confront to existing experimental data on pp and p¯p total and differential cross sections at s≥19GeV and |t|≤14.2GeV2 including the newest TOTEM data. Predictions for the future TOTEM measurements at 13 and 14 TeV are given.

  17. Empirical parametrization of the two-photon-exchange effect contributions to the electron-proton elastic scattering cross section

    SciTech Connect

    Qattan, I. A.; Alsaad, A.

    2011-05-15

    The most recent electron-proton elastic scattering data were re-analyzed using an empirical parametrization of the two-photon-exchange (TPE) effect contributions to {sigma}{sub R}. The TPE effect contribution F(Q{sup 2},{epsilon}) was double Taylor series expanded as a polynomial of order n keeping only terms linear in {epsilon} to account for the experimentally observed and verified linearity of the Rosenbluth plots. We fix the ratio R=G{sub Ep}/G{sub Mp} to be that obtained from a fit to the recoil-polarization data and parametrize {sigma}{sub R} first by a three-parameter formula (fit I) and then by a two-parameter formula (fit III). In contrast to previous analyses, the fit parameter G{sub Mp}{sup 2} as obtained from these fits is either smaller or equal to the values obtained from our conventional Rosenbluth fit (fit II) but never larger. The ratio g(Q{sup 2})/G{sub Mp}{sup 2} which represents the ratio of the TPE and one-photon-exchange (OPE) effect contributions to the intercept of {sigma}{sub R} is large and it ranges 3%-88%. The ratio R{sub 1{gamma}x2{gamma}={tau}}f(Q{sup 2})/G{sub Ep}{sup 2} which represents the ratio of the TPE and OPE effect contributions to the slope of {sigma}{sub R} is also large, reaching a value of 12.0-14.4 at Q{sup 2}= 5.25 (GeV/c){sup 2}. The ratio R{sub 1{gamma}x2{gamma}} as obtained from fits I and III is consistent, within error, with those obtained from previous analyses. Our formulas seem to explain the linearity of {sigma}{sub R}. Moreover, our analysis shows that the extracted G{sub Ep}{sup 2} and G{sub Mp}{sup 2} using the conventional Rosenbluth separation method can in fact be broken into the usual OPE and TPE contributions. Therefore, {sigma}{sub R} can in fact be derived under weaker conditions than those imposed by the Born approximation. Our results show that the TPE amplitudes, g(Q{sup 2})/G{sub Mp}{sup 2} and f(Q{sup 2})/G{sub Mp}{sup 2}, are sizable and grow with Q{sup 2} value up to Q{sup 2}{approx}6 (Ge

  18. Measurement of the analyzing power for pion proton elastic scattering between 471 and 687 MeV/c

    SciTech Connect

    Mokhtari-Amirmajdi, A.

    1985-06-01

    The analyzing power, A/sub N/, has been measured for ..pi../sup + -/p..--> pi../sup + -/p at 471, 547, 625, and 687 MeV/c in an angular range corresponding to -0.9 less than or equal to cos theta/sub cm/ less than or equal to 0.8. A polarized proton target with polarization axis normal to the scattering plane was used. The scattered pion and recoil proton were detected in coincidence, using a magnetic spectrometer and a wire chamber/scintillator array, except in cases where one of the particles was kinematically inaccessible. Statistical uncertainties in the data are as low as 0.02; systematic uncertainties are estimated to be less than 3%. The ..pi../sup -/p data are characterized by large values of analyzing power, and rapid variations in the angular distribution with incident momentum. The measurements are compared with the results of existing partial wave analysis.

  19. Probing the cluster structure of 7Li via elastic scattering on protons and deuterons in inverse kinematics

    NASA Astrophysics Data System (ADS)

    Pakou, A.; Soukeras, V.; Cappuzzello, F.; Acosta, L.; Agodi, C.; Aslanoglou, X.; Calabrese, S.; Carbone, D.; Cavallaro, M.; Foti, A.; Keeley, N.; Marquinez-Duran, G.; Martel, I.; Mazzocco, M.; Parascandolo, C.; Pierroutsakou, D.; Rusek, K.; Sgouros, O.; Strano, E.; Zagatto, V. A. B.

    2016-07-01

    Elastic scattering measurements were performed for the 7Li+p system in inverse kinematics at energies of 16, 25, 35, and 38.1 MeV and for the 7Li+d system at 38.1 MeV. The heavy ejectiles were detected by the large acceptance MAGNEX spectrometer at the Laboratori Nazionali del Sud in Catania, Italy. The results are analyzed using the Jeukenne-Lejeune-Mahaux and continuum discretized coupled channel frameworks. In the latter case the cluster structure of 7Li proves to be critical for the theoretical interpretation of the experimental results.

  20. Nucleas (hadron) nucleus elastic scattering and geometrical picture

    SciTech Connect

    Aleem F.; Ali, S.; Saleem, M.

    1995-08-01

    A comprehensive explanation of nucleus-nucleus and hadron-nucleus elastic scattering is elusive ever since the measurements of these reactions were made. By proposing energy dependent hadronic form factors for deuteron and alpha, in analogy to that of the proton as suggested by Chou and Yang recently, the authors have fitted all the available data for alpha-alpha and deuteron-deuteron elastic scattering. In order to further verify the validity of the proposed form factor, they have also fitted the data for proton-alpha and proton-deuteron elastic scattering. It is concluded that the hadronic matter is expanding with an increase in energy. 30 refs., 11 figs.

  1. Two-photon exchange corrections to elastic electron-proton scattering at large momentum transfer within the SCET approach

    NASA Astrophysics Data System (ADS)

    Kivel, N.; Vanderhaeghen, M.

    2013-04-01

    We calculate the two-photon exchange (TPE) corrections in the region where the kinematical variables describing the elastic ep scattering are moderately large momentum scales relative to the soft hadronic scale. For such kinematics we use the QCD factorization approach formulated in the framework of the soft-collinear effective theory (SCET). Such technique allows us to develop a description for the soft-spectator scattering contribution which is found to be important in the region of moderately large scales. Together with the hard-spectator contribution we present the complete factorization formulas for the TPE amplitudes at the leading power and leading logarithmic accuracy. The momentum region where both photons are hard is described by only one new nonperturbative SCET form factor. It turns out that the same form factor also arises for wide-angle Compton scattering which is also described in the framework of the SCET approach. This allows us to estimate the soft-spectator contribution associated with the hard photons in a model independent way. The main unknown in our description of the TPE contribution is related with the configuration where one photon is soft. The nonperturbative dynamics in this case is described by two unknown SCET amplitudes. We use a simple model in order to estimate their contribution. The formalism is then applied to a phenomenological analysis of existing data for the reduced cross section as well as for the transverse and longitudinal polarization observables.

  2. Determination of the weak charge of the proton through parity violating asymmetry measurements in the elastic e+p scattering

    NASA Astrophysics Data System (ADS)

    Subedi, Adesh

    The Qweak experiment has taken data to make a 2.5% measurement of parity violating elastic e+p asymmetry in the four momentum transfer region of 0.0250 (GeV/c)2. This asymmetry is proportional to the weak charge of the proton, which is related to the weak mixing angle, sin2θ W. The final Qweak measurement will provide the most precise measurement of the weak mixing angle below the Z° pole to test the Standard Model prediction. A description of the experimental apparatus is provided in this dissertation. The experiment was carried out using a longitudinally polarized electron beam of up to 180 muA on a 34.5 cm long unpolarized liquid hydrogen target. The Qweak target is not only the world's highest cryogenic target ever built for a parity experiment but also is the least noisy target. This dissertation provides a detailed description of this target and presents a thorough analysis of the target performance. Statistical analysis of Run 1 data, collected between Feb--May 2011, is done to extract a blinded parity violating asymmetry of size--299.7 +/- 13.4 (stat.) +/- 17.2 (syst.) +/- 68 (blinding) parts-per-billion. This resulted in a preliminary proton's weak charge of value 0.0865 +/- 0.0085, a 9% measurement. Based on this blinded asymmetry, the weak mixing angle was determined to be sin2θW = 0.23429 +/- 0.00211.

  3. Microscopic analysis of Be,1110 elastic scattering on protons and nuclei, and breakup processes of 11Be within the 10Be +n cluster model

    NASA Astrophysics Data System (ADS)

    Lukyanov, V. K.; Kadrev, D. N.; Zemlyanaya, E. V.; Spasova, K.; Lukyanov, K. V.; Antonov, A. N.; Gaidarov, M. K.

    2015-03-01

    The density distributions of 10Be and 11Be nuclei obtained within the quantum Monte Carlo model and the generator coordinate method are used to calculate the microscopic optical potentials (OPs) and cross sections of elastic scattering of these nuclei on protons and 12C at energies E <100 MeV/nucleon. The real part of the OP is calculated using the folding model with the exchange terms included, while the imaginary part of the OP that reproduces the phase of scattering is obtained in the high-energy approximation. In this hybrid model of OP the free parameters are the depths of the real and imaginary parts obtained by fitting the experimental data. The well-known energy dependence of the volume integrals is used as a physical constraint to resolve the ambiguities of the parameter values. The role of the spin-orbit potential and the surface contribution to the OP is studied for an adequate description of available experimental elastic scattering cross-section data. Also, the cluster model, in which 11Be consists of a n -halo and the 10Be core, is adopted. Within the latter, the breakup cross sections of 11Be nucleus on 9Be,93Nb,181Ta , and 238U targets and momentum distributions of 10Be fragments are calculated and compared with the existing experimental data.

  4. Determination of the weak charge of the proton through parity violating asymmetry measurements in the elastic e+p scattering

    SciTech Connect

    Subedi, Adesh

    2014-12-01

    The Qweak experiment has taken data to make a 2.5% measurement of parity violating elastic e+p asymmetry in the four momentum transfer region of 0.0250 (GeV/c)2. This asymmetry is proportional to the weak charge of the proton, which is related to the weak mixing angle, sin2(theta_W). The final Qweak measurement will provide the most precise measurement of the weak mixing angle below the Z0 pole to test the Standard Model prediction. A description of the experimental apparatus is provided in this dissertation. The experiment was carried out using a longitudinally polarized electron beam of up to 180 microampere on a 34.5 cm long unpolarized liquid hydrogen target. The Qweak target is not only the world's highest cryogenic target ever built for a parity experiment but also is the least noisy target. This dissertation provides a detailed description of this target and presents a thorough analysis of the target performance. Statistical analysis of Run 1 data, collected between Feb - May 2011, is done to extract a blinded parity violating asymmetry of size -299.7 ± 13.4 (stat.) ± 17.2 (syst.) ± 68 (blinding) parts-per-billion. This resulted in a preliminary proton's weak charge of value 0.0865 ± 0.0085, a 9% measurement. Based on this blinded asymmetry, the weak mixing angle was determined to be sin2(theta_W) = 0.23429 ± 0.00211.

  5. Elastic and inelastic scattering of polarized protons from carbon-12 at 400, 600, and 700 MeV

    SciTech Connect

    Jones, K.W.

    1984-04-01

    Good resolution cross section and analyzing power (p vector, p') data for many states in /sup 12/C up to an excitation energy of 21 MeV and spanning a momentum transfer range of 0.3 to 2.1 fm/sup -1/ were obtained using the High Resolution Spectrometer at the Clinton P. Anderson Meson Physics Facility at incident beam energies of 398, 597, and 698 MeV. Optical model potentials were obtained from the elastic scattering data. Inelastic data were analyzed in the Distorted Wave Impulse Approximation using the Love-Franey effective nucleon-nucleon interaction. The energy dependent isoscalar natural parity cross sections were underestimated, while phase difficulties were encountered in fitting analyzing powers. The energy independent isovector natural parity cross sections were reasonably reproduced, but analyzing powers were not, the calculations yielding positive trends whereas the data are of opposite sign. The energy independent isoscalar and isovector unnatural parity cross sections were quite well reproduced up to moderate momentum transfers, and striking successes were observed for some analyzing power data. Systematics of energy dependence together with the results of the DWIA calculations permitted the assignment of spin, parity and isospin quantum numbers to states in the 18-21 MeV excitation region. 64 references.

  6. Elastic and diffractive scattering at D0

    SciTech Connect

    Edwards, Tamsin; /Manchester U.

    2004-04-01

    The first search for diffractively produced Z bosons in the muon decay channel is presented, using a data set collected by the D0 detector at the Fermilab Tevatron at {radical}s = 1.96 TeV between April and September 2003, corresponding to an integrated luminosity of approximately 110 pb{sup -1}. The first dN/d|t| distribution for proton-antiproton elastic scattering at this c.o.m. energy is also presented, using data collected by the D0 Forward Proton Detector between January and May 2002. The measured slope is reproduced by theoretical predictions.

  7. Proton resonance scattering of 7Be

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; Saito, A.; He, J. J.; Wakabayashi, Y.; Amadio, G.; Fujikawa, H.; Kubono, S.; Khiem, L. H.; Kwon, Y. K.; Niikura, M.; Teranishi, T.; Nishimura, S.; Togano, Y.; Iwasa, N.; Inafuku, K.

    2006-07-01

    We have studied the proton resonance scattering of 7Be by using a pure 7Be beam produced at CRIB (CNS Radioactive Ion Beam separator; CNS stands for Center of Nuclear Study, University of Tokyo). The excitation function of 8B was measured up to the excitation energy of 6.8 MeV, with the thick-target method. The excited states of 8B higher than 3.5 MeV were not known by the past experiments. This proton elastic scattering is also of importance in relation with the 7Be(p,γ)8B reaction, which is a key reaction in the standard solar model.

  8. Systematic CDCC calculations for 11Be + p elastic scattering

    NASA Astrophysics Data System (ADS)

    Chen, Jie; Lou, JianLing; Pang, DanYang; Ye, YanLin

    2016-03-01

    Continuum discretised coupled-channels (CDCC) method with a 10Be(0+) + n two-body cluster model is applied to systematically analyze the elastic scattering of the halo nucleus 11Be from the proton target at various incident energies below 100 MeV/nucleon. Using the renormalized 10Be- p potential deduced from the 10Be + p elastic scattering data, the differential cross sections of 11Be + p scattering are well reproduced by the CDCC calculations without any further adjustment parameters, demonstrating the applicability of this approach for describing the scattering of exotic nuclei based on the scattering of the less exotic core nuclei.

  9. Microscopic analysis of 10,11Be elastic scattering on protons and 12C and breakup processes of 11Be within the 10Be+n cluster model

    NASA Astrophysics Data System (ADS)

    Spasova, K.; Lukyanov, V. K.; Kadrev, D. N.; Antonov, A. N.; Zemlyanaya, E. V.; Lukyanov, K. V.; Gaidarov, M. K.

    2016-06-01

    The elastic scattering cross-sections of 10,11Be on protons and 12C at energy E < 100 MeV/nucleon using microscopically calculated optical potentials (OP) are presented. The real OP is obtained by a folding procedure with effective NN interactions, while the imaginary OP is estimated within the high energy approximation (HEA). The spin-orbit part of the OP is also included. The characteristics of the breakup processes of 11Be on different nuclear targets are also considered. The cross-sections of diffractive breakup and stripping reactions of 11Be on 9Be, 93Nb, 181Ta and 238U at energy E = 63 MeV/nucleon and the longitudinal momentum distributions of 10Be fragments produced in the breakup of 11Be on these nuclei are presented. The results are in a good agreement with the available experimental data, in particular the obtained widths of about 50 MeV/c are closed to the empirical ones.

  10. Two-photon exchange in electron-trinucleon elastic scattering

    NASA Astrophysics Data System (ADS)

    Kobushkin, A. P.; Timoshenko, Ju. V.

    2013-10-01

    We discuss two-photon exchange (TPE) in elastic electron scattering off the trinucleon systems, 3He and 3H. The calculations are done in the semirelativistic approximation with the trinucleon wave functions obtained with the Paris and CD-Bonn nucleon-nucleon potentials. An applicability area of the model is wide enough and includes the main part of kinematical domain where experimental data exist. All three TPE amplitudes (generalized form factors) for electron 3He elastic scattering are calculated. We find that the TPE amplitudes are a few times more significant in the scattering of electrons off 3He then in the electron-proton scattering.

  11. Electron-Hydrogen Elastic Scattering

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.

    2004-01-01

    Scattering by single-electron systems is always of interest because the wave function of the target is known exactly. Various approximations have been employed to take into account distortion produced in the target. Among them are the method of polarized orbitals and the close coupling approximation. Recently, e-H and e-He+ S-wave scattering in the elastic region has been studied using the Feshbach projection operator formalism. In this approach, the usual Hartree-Fock and exchange potentials are augmented by an optical potential and the resulting phase shifts have rigorous lower bounds. Now this method is being applied to the e-H P-wave scattering in the elastic region. The number of terms in the Hylleraas-type wave function for the 1,3 P phase shifts is 84 and the resulting phase shifts (preliminary) are given. The results have been given up to five digits because to that accuracy they are rigorous lower bounds. They are in general agreement with the variational (VAR) results of Armstead, and those obtained from the intermediate energy R-matrix method (RM) of Scholz et al., and the finite element method (FEM) of Botero and Shertzer. The later two methods do not provide any bounds on phase shifts.

  12. Measurement of the polarization parameter in proton-neutron elastic scattering at 1. 30, 1. 39, 1. 59, and 1. 82 GeV/c

    SciTech Connect

    Sakuda, M.; Isagawa, S.; Ishimoto, S.; Kabe, S.; Masaike, A.; Morimoto, K.; Ogawa, K.; Suetake, M.; Takasaki, F.; Watase, Y.; Kim, N.; Kobayashidouble-dagger, S.; Murakami, A.; de Lesguen, A.; Nakajima, K.; Nakada, S.; Wada, T.; Yamachi, I.

    1982-04-01

    The polarization parameters of the pn elastic scattering were measured at beam momenta between 1.30 and 1.82 GeV/c. The results are discussed in comparison with the partial-wave analysis of Hashimoto and Hoshizaki.

  13. Elastic scattering with weakly bound projectiles

    SciTech Connect

    Figueira, J. M.; Abriola, D.; Arazi, A.; Capurro, O. A.; Marti, G. V.; Martinez Heinmann, D.; Pacheco, A. J.; Testoni, J. E.; Barbara, E. de; Fernandez Niello, J. O.; Padron, I.; Gomes, P. R. S.; Lubian, J.

    2007-02-12

    Possible effects of the break-up channel on the elastic scattering threshold anomaly has been investigated. We used the weakly bound 6,7Li nuclei, which is known to undergo break-up, as projectiles in order to study the elastic scattering on a 27Al target. In this contribution we present preliminary results of these experiments, which were analyzed in terms of the Optical Model and compared with other elastic scattering data using weakly bound nuclei as projectile.

  14. Evaluation of the Proton Charge Radius from Electron–Proton Scattering

    SciTech Connect

    Arrington, John; Sick, Ingo

    2015-09-15

    In light of the proton radius puzzle, the discrepancy between measurements of the proton charge radius from muonic hydrogen and those from electronic hydrogen and electron–proton (e–p) scattering measurements, we re-examine the charge radius extractions from electron scattering measurements. We provide a recommended value for the proton root-mean-square charge radius, r{sub E} = 0.879 ± 0.011 fm, based on a global examination of elastic e–p scattering data. The uncertainties include contributions to account for tension between different data sets and inconsistencies between radii using different extraction procedures.

  15. Decoherence due to Elastic Rayleigh Scattering

    NASA Astrophysics Data System (ADS)

    Uys, H.; Biercuk, M. J.; Vandevender, A. P.; Ospelkaus, C.; Meiser, D.; Ozeri, R.; Bollinger, J. J.

    2010-11-01

    We present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of light off resonant with higher lying excited states. We demonstrate that under appropriate conditions, elastic Rayleigh scattering can be the dominant source of decoherence, contrary to previous discussions in the literature. We show that the elastic-scattering decoherence rate of a two-level system is given by the square of the difference between the elastic-scattering amplitudes for the two levels, and that for certain detunings of the light, the amplitudes can interfere constructively even when the elastic-scattering rates from the two levels are equal. We confirm this prediction through calculations and measurements of the total decoherence rate for a superposition of the valence electron spin levels in the ground state of Be+9 in a 4.5 T magnetic field.

  16. Decoherence due to elastic Rayleigh scattering.

    PubMed

    Uys, H; Biercuk, M J; Vandevender, A P; Ospelkaus, C; Meiser, D; Ozeri, R; Bollinger, J J

    2010-11-12

    We present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of light off resonant with higher lying excited states. We demonstrate that under appropriate conditions, elastic Rayleigh scattering can be the dominant source of decoherence, contrary to previous discussions in the literature. We show that the elastic-scattering decoherence rate of a two-level system is given by the square of the difference between the elastic-scattering amplitudes for the two levels, and that for certain detunings of the light, the amplitudes can interfere constructively even when the elastic-scattering rates from the two levels are equal. We confirm this prediction through calculations and measurements of the total decoherence rate for a superposition of the valence electron spin levels in the ground state of 9Be+ in a 4.5 T magnetic field. PMID:21231210

  17. Study of Proton Resonances in 2626Si and 27P by the Elastic Scattering of 1H(25Al, p) 25Al, 1H(26Si, p)26Si

    NASA Astrophysics Data System (ADS)

    Moon, J. Y.; Lee, C. S.; Lee, J. H.; Yun, C. C.; Kim, J. C.; Youn, M.; Kubono, S.; Teranishi, T.; He, J. J.; Notani, M.; Nishimura, S.; Nishimura, M.; Guimarães, V.; Lihitenthaler, R. F.; Kato, S.

    2005-12-01

    The observational space map of 1.809-MeV gamma rays - coming from the decay of 26Al - taken by COMPTEL requires the sources and their nucleosynthetic activity to be unveiled. One suggestion for the observation is the explosive hydrogen burning process which occurs in novae or X-ray bursts. Two capture reactions such as 25 Al(p,γ)26Si and 26Si(p,γ)27P are of great importance in the production of 1.809-MeV gamma rays. Resonance states within the Gamow window should be precisely known to determine their reaction rates. As for the latter reaction, only a few levels in 27P have been known above the proton threshold in comparison with many levels known in its mirror nucleus 27Mg. We studied proton resonances in 26Si and 27P by the elastic scattering at low energies, respectively using low-energy 25Al and 26Si radioactive ion beams available from the CRIB facility at CNS, University of Tokyo. We carried out an experiment to investigate proton resonances in 26Si up to EC.M. = 3.016 MeV, especially to determine the resonance parameters of the states at Ex = 7.019 and 8.120 MeV. We also measured the elastic scattering of p + 26Si up to EC.M. = 3.290 MeV.

  18. Analysis of elastic scattering and breakup of {sup 11}li in collisions with protons using a dynamical two-cluster model

    SciTech Connect

    Lukyanov, V. K. Zemlyanaya, E. V.; Lukyanov, K. V.

    2015-01-15

    The {sup 11}Li scattering and breakup on protons is considered under the assumption that the {sup 11}Li nucleus consists of two interacting clusters, which are a c = {sup 9}Li core and a h = 2n dineutron halo. The single-particle density of the {sup 11}Li nucleus, amicroscopic optical potential, and the cross section for {sup 11}Li+p scattering for various choices of cluster shape are obtained and analyzed by folding the density distribution for either cluster with the probability density for the relative motion of two clusters. A comparison with experimental data of the scattering cross section at low, 60–75 MeV, and intermediate, 700 MeV, energies is performed. The momentum distribution of c fragments upon {sup 11}Li breakup is calculated and studied with a help of the obtained p + c and p + h microscopic optical potentials.

  19. Measurement of the transverse beam spin asymmetry in elastic electron-proton scattering and the inelastic contribution to the imaginary part of the two-photon exchange amplitude.

    PubMed

    Maas, F E; Aulenbacher, K; Baunack, S; Capozza, L; Diefenbach, J; Gläser, B; Imai, Y; Hammel, T; von Harrach, D; Kabuss, E-M; Kothe, R; Lee, J H; Sanchez-Lorente, A; Schilling, E; Schwaab, D; Stephan, G; Weber, G; Weinrich, C; Altarev, I; Arvieux, J; Elyakoubi, M; Frascaria, R; Kunne, R; Morlet, M; Ong, S; Vandewiele, J; Kowalski, S; Suleiman, R; Taylor, S

    2005-03-01

    We report on a measurement of the asymmetry in the scattering of transversely polarized electrons off unpolarized protons, A( perpendicular), at two Q2 values of 0.106 and 0.230 (GeV/c)(2) and a scattering angle of 30 degrees proton. PMID:15783877

  20. Spatial measure of reaction size in proton scattering

    NASA Astrophysics Data System (ADS)

    Ito, Makoto; Iwasaki, Masataka; Otani, Reiji; Tomita, Masashi

    2016-06-01

    The microscopic coupled-channel (MCC) calculations for proton + 12C inelastic scattering are performed in the energy range of Ep = 29.95 MeV to 65 MeV. The nuclear interactions for the proton -12C system are constructed from the folding model, which employs the internal wave function of 12C, obtained from the 3α resonating group method (3α RGM), and an effective nucleon-nucleon interaction of the density-dependent Michigan three-range Yukawa (DDM3Y). The MCC calculation with the 3α RGM + DDM3Y nicely reproduces all of the differential cross sections for elastic and inelastic scattering in the angular range of θc.m. = 30° to 120°. We introduce a scattering radius, which characterizes a spatial size of the scattering area, from partial wave decompositions of an angle-integrated cross section. The scattering radii for the elastic scattering and the various inelastic channels, which involve the rotational or vibrational excitations and the 3α excitations in 12C, are derived. We found that the scattering radii for the inelastic channels with a well developed 3α structure are strongly enhanced in comparison to the scattering radii for the elastic and collective channels. This enhancement of the scattering radius for the 3α channel strongly suggests that the scattering radius is sensitive to a size of the intrinsic structure of the finally excited state in the scattering process.

  1. Backward elastic pd scattering at 316, 364, 470 and 590 MeV

    NASA Technical Reports Server (NTRS)

    Alder, J. C.; Dollhopf, W.; Lunke, C.; Perdrisat, C. F.; Roberts, W. K.; Kitching, P.; Moss, G. F.; Olsen, W. C.; Priest, J. R.

    1971-01-01

    Preliminary results are reported from a part of the data obtained at the NASA Space Radiation Effect Laboratory for the elastic scattering of protons by deuterons in the backward hemisphere. The data is averaged over a proton angle interval which corresponds to the angular resolution on the correlation angle, given the proton bin used in the data analysis.

  2. A study of the proton resonant property in 22Mg by elastic scattering of 21Na + p and its astrophysical implication in the 18Ne(α, p)21Na reaction rate

    NASA Astrophysics Data System (ADS)

    He, J. J.; Kubono, S.; Teranishi, T.; Notani, M.; Baba, H.; Nishimura, S.; Moon, J. Y.; Nishimura, M.; Michimasa, S.; Iwasaki, H.; Yanagisawa, Y.; Hokoiwa, N.; Kibe, M.; Lee, J. H.; Kato, S.; Gono, Y.; Lee, C. S.

    2008-04-01

    Proton resonances in 22Mg have been investigated by the resonant elastic scattering of 21 Na + p . The 21Na beam with a mean energy of 4.00 MeV/nucleon was separated by the CNS radioactive-ion-beam separator (CRIB) and bombarded a thick ( CH2 n target. The energy spectra of recoiled protons were measured at scattering angles of θc.m. ≈ 172° , 146° , respectively. Several excited states observed before have been confirmed including two states (at 6.616, 6.796 MeV) observed at TRIUMF. A new state at 7.06 MeV has been observed, and another new one at 7.28 MeV is tentatively identified due to its low statistics. The proton resonant parameters were deduced from an R -matrix analysis of the differential cross-section data with a SAMMY-M6-BETA code. The astrophysical implication for the 18 Ne(α, p)21 Na reaction has been briefly discussed.

  3. Asymmetry Measurement in the Elastic Pion-Proton Scattering at 1.94 and 2.07 GeV/c

    SciTech Connect

    Alekseev, I. G.; Budkovsky, P. E.; Kanavets, V. P.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Ryltsov, V. V.; Sulimov, A. D.; Svirida, D. N.; Zhurkin, V. V.; Bazhanov, N. A.; Bunyatova, E. I.; Zolin, L. S.; Beloglazov, Yu. A.; Filimonov, E. A.; Kovalev, A. I.; Kruglov, S. P.; Novinsky, D. V.; Shchedrov, V. A.; Sumachev, V. V.

    2007-06-13

    Latest results by the ITEP-PNPI collaboration on the asymmetry in the {pi}+p elastic scattering are presented. The data were obtained for the first time in the region of backward angles with low cross section, where the predictions of the partial wave analyses are not reliable. The results at 1.94 GeV/c are in favor of the older KH80 analysis and show noticeable deviation from the latest FA06 solution by GWU group. At 2.07 GeV/c very low cross section did not allow to achieve good accuracy. Yet the data do not follow any of the PWA predictions and definitely disagree with SP06 analysis.

  4. Inversion problem for ion-atom differential elastic scattering.

    NASA Technical Reports Server (NTRS)

    Rich, W. G.; Bobbio, S. M.; Champion, R. L.; Doverspike, L. D.

    1971-01-01

    The paper describes a practical application of Remler's (1971) method by which one constructs a set of phase shifts from high resolution measurements of the differential elastic scattering of protons by rare-gas atoms. These JWKB phase shifts are then formally inverted to determine the corresponding intermolecular potentials. The validity of the method is demonstrated by comparing an intermolecular potential obtained by direct inversion of experimental data with a fairly accurate calculation by Wolniewicz (1965).

  5. Decoherence due to elastic Rayleigh scattering

    NASA Astrophysics Data System (ADS)

    Uys, H.; Biercuk, M. J.; Vandevender, A. P.; Ospelkaus, C.; Bollinger, J. J.; Meiser, D.

    2010-03-01

    Off-resonant light scattering (spontaneous emission) is an important source of decoherence in many coherent control experiments. Typically one focuses on the effects of Raman scattering, in which an atomic state is changed by a single scattering event. We present theoretical and experimental studies of the decoherence of hyperfine ground-state superpositions due to elastic Rayleigh scattering of off-resonant light. By a master equation technique we show that for a two-level superposition the elastic decoherence rate is the square of the difference between the two elastic scattering amplitudes. Thus, if the light detunings for the two states have opposite sign, the amplitudes interfere constructively and can result in a large decoherence rate. We calculate and measure the total decoherence rate for a superposition state of the valence electron spin in the ground state of ^9Be^+ in a 4.5 T magnetic field. We find that for large (˜20 GHz) detunings, decoherence due to elastic Rayleigh scattering can be 5 times larger than decoherence due to Raman scattering. This is in contrast with workootnotetextR. Ozeri, et al., PRL 95, 030403 (2005) at low magnetic field where decoherence was dominated by Raman scattering.

  6. Proton-Proton Scattering at 105 Mev and 75 Mev

    DOE R&D Accomplishments Database

    Birge, R. W.; Kruse, U. E.; Ramsey, N. F.

    1951-01-31

    The scattering of protons by protons provides an important method for studying the nature of nuclear forces. Recent proton-proton scattering experiments at energies as high as thirty Mev{sup 1} have failed to show any appreciable contribution to the cross section from higher angular momentum states, but it is necessary to bring in tensor forces to explain the magnitude of the observed cross section.

  7. Hadronic uncertainties in the elastic scattering of supersymmetric dark matter

    SciTech Connect

    Ellis, John; Olive, Keith A.; Savage, Christopher

    2008-03-15

    We review the uncertainties in the spin-independent and spin-dependent elastic scattering cross sections of supersymmetric dark matter particles on protons and neutrons. We propagate the uncertainties in quark masses and hadronic matrix elements that are related to the {pi}-nucleon {sigma} term and the spin content of the nucleon. By far the largest single uncertainty is that in spin-independent scattering induced by our ignorance of the matrix elements linked to the {pi}-nucleon {sigma} term, which affects the ratio of cross sections on proton and neutron targets as well as their absolute values. This uncertainty is already impacting the interpretations of experimental searches for cold dark matter. We plead for an experimental campaign to determine better the {pi}-nucleon {sigma} term. Uncertainties in the spin content of the proton affect significantly, but less strongly, the calculation of rates used in indirect searches.

  8. Elastic scattering and reactions of light exotic beams

    NASA Astrophysics Data System (ADS)

    Keeley, N.; Alamanos, N.; Kemper, K. W.; Rusek, K.

    2009-10-01

    The present work provides a literature survey of elastic scattering of exotic nuclei from 6He to 17F. It presents a set of definitions that allow different analyses to be put into a common language. A calculational approach is proposed that yields consistent results across different beams and targets so that conclusions concerning the influence of virtual and real breakup as well as transfer couplings on the elastic scattering may be drawn. Calculations of elastic scattering around the Coulomb barrier are emphasised, employing a Pb target whose large Z allows the interplay between nuclear and Coulomb forces to be exploited to maximise possible effects arising from proton or neutron haloes or skins. A series of test calculations is performed and where possible compared to data, demonstrating that there are instances where coupling to transfer channels can have a large effect on the elastic scattering angular distributions. By careful choice of target/beam combination, different aspects of the coupling effects may be emphasised.

  9. Elastic Hadron Scattering on Li Isotopes at Intermediate Energies

    SciTech Connect

    Zhusupov, M.A.; Imambekov, O.; Ibraeva, E.T.

    2005-01-01

    The elastic scattering of hadrons (protons, charged pions, and positively charged kaons) on {sup 6,7,8}Li nuclei is analyzed on the basis of Glauber-Sitenko diffraction theory. A few nuclear-wave-function versions found within two- and three-particle potential cluster models are used in the calculations. It is shown that the application of these wave functions in diffraction theory makes it possible to describe adequately the experimental differential cross sections and analyzing powers in hadron scattering at intermediate energies. In this study, particular attention is given to a comparison of the scattering of different particles on the same target nucleus, as well as to a comparison of scattering of particles of the same sort on different target nuclei.

  10. Coherent elastic neutrino-nucleus scattering

    NASA Astrophysics Data System (ADS)

    Scholberg, Kate

    2015-05-01

    I describe physics potential and experimental prospects for coherent elastic neutrino-nucleus scattering (CEvNS), a process which has not yet been observed. Germanium- based detectors represent a promising technology for CEvNS experiments. I focus primarily on stopped-pion neutrino sources.

  11. Elastic electron scattering by ethyl vinyl ether

    SciTech Connect

    Khakoo, M. A.; Hong, L.; Kim, B.; Winstead, C.; McKoy, V.

    2010-02-15

    We report measured and calculated results for elastic scattering of low-energy electrons by ethyl vinyl ether (ethoxyethene), a prototype system for studying indirect dissociative attachment processes that may play a role in DNA damage. The integral cross section displays the expected {pi}{sup *} shape resonance. The agreement between the calculated and measured cross sections is generally good.

  12. Asymptotic behaviour of backward elastic scattering

    NASA Astrophysics Data System (ADS)

    Germond, J. F.; Lombard, R. J.

    1988-05-01

    We discuss a compact formula proposed by Dias de Deus and Pimenta for the asymptotic value of the elastic scattering amplitude at backward angles. Improvements and generalization are obtained by means of the saddle-point method which corroborate old calculations by Serber.

  13. Neutron densities in 120Sn observed by polarized proton scattering

    NASA Astrophysics Data System (ADS)

    Sakaguchi, H.; Takeda, H.; Taki, T.; Yosoi, M.; Itoh, M.; Kawabata, T.; Ishikawa, T.; Uchida, M.; Tsukahara, N.; Noro, T.; Yoshimura, M.; Fujimura, H.; Yoshida, H.; Obayashi, E.; Tamii, A.; Akimune, H.

    2001-06-01

    Cross sections, analyzing powers and spin rotation parameters of proton elastic scattering from 58Ni and 120Sn have been measured at intermediate energies. By elastic scattering off N~=Z nuclei like 58Ni at intermediate energies we can study medium modification of the nucleon-nucleon (NN) interaction inside the nucleus, because proton distributions in target nuclei are constrained by charge distributions measured by electron scattering and neutron distributions can be assumed to be the same as proton's. In order to explain our experimental data of 58Ni at large scattering angles, it was found to be necessary to use experimental densities deduced from charge densities measured by electron scattering and to modify the coupling constants and the masses of exchanged σ and ω mesons in the RIA, assuming linear dependencies of meson properties to nuclear densities. Parameters of the medium effect have been searched to reproduce the data. For N≠Z nuclei, neutron density distribution can be extracted from the elastic scattering, assuming the same medium modifications fixed by the 58Ni data and using proton distributions obtained from charge distributions. We have searched neutron density distributions obtained from charge distributions. We have searched neutron density distribution so as to reproduce 120Sn data at the proton incident energy of 300 MeV. Deduced neutron distribution has an increase at the nuclear center, which is consistent with the 3s1/2 orbit wave function as expected in 120Sn. At energies other than 300 MeV, experimental data of 120Sn have been also well reproduced by the neutron distribution obtained at 300 MeV. .

  14. Excitation function of elastic pp scattering from a unitarily extended Bialas-Bzdak model

    NASA Astrophysics Data System (ADS)

    Nemes, F.; Csörgő, T.; Csanád, M.

    2015-05-01

    The Bialas-Bzdak model of elastic proton-proton scattering assumes a purely imaginary forward scattering amplitude, which consequently vanishes at the diffractive minima. We extended the model to arbitrarily large real parts in a way that constraints from unitarity are satisfied. The resulting model is able to describe elastic pp scattering not only at the lower ISR energies but also at √ {s} = 7 TeV in a statistically acceptable manner, both in the diffractive cone and in the region of the first diffractive minimum. The total cross-section as well as the differential cross-section of elastic proton-proton scattering is predicted for the future LHC energies of √ {s} = 13, 14, 15 TeV and also to 28 TeV. A nontrivial, significantly nonexponential feature of the differential cross-section of elastic proton-proton scattering is analyzed and the excitation function of the nonexponential behavior is predicted. The excitation function of the shadow profiles is discussed and related to saturation at small impact parameters.

  15. Results on neutrino-electron elastic scattering at AGS energies

    SciTech Connect

    Lanou, R.E.

    1984-02-26

    In an experiment designed to study elastic scattering of nu/sub ..mu../ (and anti nu/sub ..mu../) from electrons and protons via the weak neutral current, we have recently completed several extensive data taking runs. Results for the cross section of nu/sub ..mu../ + e/sup -/ ..-->.. nu/sub ..mu../ + e/sup -/ are presented based upon the first third of the available sample. Preliminary analysis of anti nu/sub ..mu../ + e/sup -/ ..-->.. anti nu/sub ..mu../ + e/sup -/ is in progress and evidence for the signal is presented.

  16. Hydrogen analysis for granite using proton-proton elastic recoil coincidence spectrometry.

    PubMed

    Komatsubara, T; Sasa, K; Ohshima, H; Kimura, H; Tajima, Y; Takahashi, T; Ishii, S; Yamato, Y; Kurosawa, M

    2008-07-01

    In an effort to develop DS02, a new radiation dosimetry system for the atomic bomb survivors of Hiroshima and Nagasaki, measurements of neutron-induced activities have provided valuable information to reconstruct the radiation situation at the time of the bombings. In Hiroshima, the depth profile of (152)Eu activity measured in a granite pillar of the Motoyasu Bridge (128 m from the hypocenter) was compared with that calculated using the DS02 methodology. For calculation of the (152)Eu production due to the thermal-neutron activation reaction, (151)Eu(n,gamma)(152)Eu, information on the hydrogen content in granite is important because the transport and slowing-down process of neutrons penetrating into the pillar is strongly affected by collisions with the protons of hydrogen. In this study, proton-proton elastic recoil coincidence spectrometry has been used to deduce the proton density in the Motoyasu pillar granite. Slices of granite samples were irradiated by a 20 MeV proton beam, and the energies of scattered and recoil protons were measured with a coincidence method. The water concentration in the pillar granite was evaluated to be 0.30 +/- 0.07%wt. This result is consistent with earlier data on adsorptive water (II) and bound water obtained by the Karl Fisher method. PMID:18509666

  17. Hard elastic scattering in QCD: Leading behavior

    SciTech Connect

    Botts, J.F.

    1989-01-01

    The author derives the asymptotic behavior of elastic meson-meson and baryon-baryon scattering at high energy and large angle t/s {approximately} O(1). The results organize both Sudakov and nonleading logarithmic corrections to independent (Landshoff) scatterings of valence quarks. He shows how to separate these contributions systematically from single scattering contributions, in a manner which suggests that the complete amplitudes should be computable perturbatively down to the dimensional counting power, in terms of hadronic wave functions. In the final chapter, the perturbative asymptotic amplitude and differential cross section for elastic pion-pion scattering is calculated numerically. For various choices of pion wave function and running coupling, the onset of power law behavior, d{sigma}/dt {approximately} s{sup {minus}5.8}, was observed. The dependence in d{sigma}/dt on the cutoff in gluon momentum, chosen to be O({Lambda}{sub QCD}/Q), was observed to be sharp for ln(s/1GeV{sup 2}) less than 1. Very small oscillations in d{sigma}/dt appear in physically realizable energies, but these are cutoff dependent, and their interpretation unclear. Higher twist effects were estimated to be roughly {approximately}15% for 2 < ln(s/1GeV{sup 2}) < 10.

  18. Positron elastic scattering from alkaline earth targets

    NASA Astrophysics Data System (ADS)

    Poveda, Luis A.; Assafrão, Denise; Mohallem, José R.

    2016-07-01

    A previously reported model potential approach [Poveda et al., Phys. Rev. A 87, 052702 (2013)] was extended to study low energy positron elastic scattering from beryllium and magnesium. The cross sections were computed for energies ranging from 10-5 eV up to well above the positronium formation threshold. The present results are in good agreement with previous reports, including the prediction of a p-wave resonance in the cross section for magnesium. The emergence of this shape resonance is connected to a trend observed in the evolution of the partial wave cross section in going from Be to Mg target. This trend lead us to speculate that a sharp d-wave resonance should be observed in positron elastic scattering from calcium. The positron-target binding energies are investigated in detail, both using the scattering information and by direct computation of the bound state energies using the model potentials. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2016-70120-y

  19. Exploring central opacity and asymptotic scenarios in elastic hadron scattering

    NASA Astrophysics Data System (ADS)

    Fagundes, D. A.; Menon, M. J.; Silva, P. V. R. G.

    2016-02-01

    In the absence of a global description of the experimental data on elastic and soft diffractive scattering from the first principles of QCD, model-independent analyses may provide useful phenomenological insights for the development of the theory in the soft sector. With that in mind, we present an empirical study on the energy dependence of the ratio X between the elastic and total cross sections; a quantity related to the evolution of the hadronic central opacity. The dataset comprises all the experimental information available on proton-proton and antiproton-proton scattering in the c.m. energy interval 5 GeV-8 TeV. Generalizing previous works, we discuss four model-independent analytical parameterizations for X, consisting of sigmoid functions composed with elementary functions of the energy and three distinct asymptotic scenarios: either the standard black disk limit or scenarios above or below that limit. Our two main conclusions are the following: (1) although consistent with the experimental data, the black disk does not represent an unique solution; (2) the data reductions favor a semi-transparent scenario, with asymptotic average value for the ratio X bar = 0.30 ± 0.12. In this case, within the uncertainty, the asymptotic regime may already be reached around 1000 TeV. We present a comparative study of the two scenarios, including predictions for the inelastic channel (diffraction dissociation) and the ratio associated with the total cross-section and the elastic slope. Details on the selection of our empirical ansatz for X and physical aspects related to a change of curvature in this quantity at 80-100 GeV, indicating the beginning of a saturation effect, are also presented and discussed.

  20. Elastic scattering, fusion, and breakup of light exotic nuclei

    NASA Astrophysics Data System (ADS)

    Kolata, J. J.; Guimarães, V.; Aguilera, E. F.

    2016-05-01

    The present status of fusion reactions involving light ( A < 20) radioactive projectiles at energies around the Coulomb barrier ( E < 10 MeV per nucleon) is reviewed, emphasizing measurements made within the last decade. Data on elastic scattering (providing total reaction cross section information) and breakup channels for the involved systems, demonstrating the relationship between these and the fusion channel, are also reviewed. Similarities and differences in the behavior of fusion and total reaction cross section data concerning halo nuclei, weakly-bound but less exotic projectiles, and strongly-bound systems are discussed. One difference in the behavior of fusion excitation functions near the Coulomb barrier seems to emerge between neutron-halo and proton-halo systems. The role of charge has been investigated by comparing the fusion excitation functions, properly scaled, for different neutron- and proton-rich systems. Possible physical explanations for the observed differences are also reviewed.

  1. Radiative corrections to polarization observables in electron-proton scattering

    NASA Astrophysics Data System (ADS)

    Borisyuk, Dmitry; Kobushkin, Alexander

    2014-08-01

    We consider radiative corrections to polarization observables in elastic electron-proton scattering, in particular, for the polarization transfer measurements of the proton form factor ratio μGE/GM. The corrections are of two types: two-photon exchange (TPE) and bremsstrahlung (BS); in the present work we pay special attention to the latter. Assuming small missing energy or missing mass cutoff, the correction can be represented in a model-independent form, with both electron and proton radiation taken into account. Numerical calculations show that the contribution of the proton radiation is not negligible. Overall, at high Q2 and energies, the total correction to μGE/GM grows, but is dominated by TPE. At low energies both TPE and BS may be significant; the latter amounts to ˜0.01 for some reasonable cut-off choices.

  2. Elastic Electron Scattering from Tritium and Helium-3

    DOE R&D Accomplishments Database

    Collard, H.; Hofstadter, R.; Hughes, E. B.; Johansson, A.; Yearian, M. R.; Day, R. B.; Wagner, R. T.

    1964-10-01

    The mirror nuclei of tritium and helium-3 have been studied by the method of elastic electron scattering. Absolute cross sections have been measured for incident electron energies in the range 110 - 690 MeV at scattering angles lying between 40 degrees and 135 degrees in this energy range. The data have been interpreted in a straightforward manner and form factors are given for the distributions of charge and magnetic moment in the two nuclei over a range of four-momentum transfer squared 1.0 - 8.0 F{sup -2}. Model-independent radii of the charge and magnetic moment distributions are given and an attempt is made to deduce form factors describing the spatial distribution of the protons in tritium and helium-3.

  3. Neutron elastic scatter for detection and identification of obscured objects

    NASA Astrophysics Data System (ADS)

    Gomberg, Henry J.; Charatis, George; Wang, David; McEllistrem, Marcus R.

    1993-11-01

    Neutron Elastic Scatter (NES) may be used for non-destructively assaying materials for the presence of narcotics, explosives, or other contraband. The technology relies on the high penetrating power of neutrons to reach through varying thickness of shielding materials, and also on the large probabilities for elastic scattering of neutrons. Elastic scattering probabilities are the largest of all neutron induced events, exceeding any single non-elastic process typically by a factor of ten or more. Indeed, usually the elastic scattering probability is larger than the sum of all inelastic processes.

  4. Elastic Scattering - Past, Present and Future

    SciTech Connect

    Fazal-e-Aleem; Rashid, Haris; Tahir, Sohail Afzal

    2007-02-14

    Various aspects of elastic and diffractive scattering have been studied at Fermilab and CERN. Search for more results is ongoing at RHIC and planned at LHC. In this talk, we review the progress made so far and elaborate future prospects. Theoretical study focuses on the analysis of the available data in the light of predictions of various models with special emphasis on Eikonal picture and QCD inspired models. In the light of this analysis, various possibilities have been explored with reference to RHIC and LHC measurements.

  5. Time reversal invariance violating and parity conserving effects in proton-deuteron scattering

    NASA Astrophysics Data System (ADS)

    Song, Young-Ho; Lazauskas, Rimantas; Gudkov, Vladimir

    2016-06-01

    Time reversal invariance violating parity conserving (TVPC) effects are calculated for elastic proton-deuteron scattering with proton energies up to 2 MeV. The distorted-wave Born approximation is employed to estimate TVPC matrix elements, based on hadronic wave functions, obtained by solving three-body Faddeev-Merkuriev equations in configuration space with realistic potentials.

  6. Multiple scattering of proton via stochastic differential equations

    NASA Astrophysics Data System (ADS)

    Kia, M. R.; Noshad, Houshyar

    2015-08-01

    Multiple scattering of protons through a target is explained by a set of coupled stochastic differential equations. The motion of protons in matter is calculated by analytical random sampling from Moliere and Landau probability density functions (PDF). To satisfy the Vavilov theory, the moments for energy distribution of a 49.1 MeV proton beam in aluminum target are obtained. The skewness for the PDF of energy demonstrates that the energy distribution of protons in thin thickness becomes a Landau function, whereas, by increasing the thickness of the target it does not follow a Gaussian function completely. Afterwards, the depth-dose distributions are calculated for a 60 MeV proton beam traversing soft tissue and for a 160 MeV proton beam travelling through water. The results prove that when elastic scattering is taken into account, the Bragg-peak position is decreased, while the dose deposited in the Bragg region is increased. The results obtained in this article are benchmarked by comparison of our results with the experimental data reported in the literature.

  7. Subcritical scattering from buried elastic shells.

    PubMed

    Lucifredi, Irena; Schmidt, Henrik

    2006-12-01

    Buried objects have been largely undetectable by traditional high-frequency sonars due to their insignificant bottom penetration. Further, even a high grazing angle sonar approach is vastly limited by the coverage rate dictated by the finite water depth, making the detection and classification of buried objects using low frequency, subcritical sonar an interesting alternative. On the other hand, such a concept would require classification clues different from the traditional high-resolution imaging and shadows to maintain low false alarm rates. A potential alternative, even for buried targets, is classification based on the acoustic signatures of man-made elastic targets. However, the elastic responses of buried and proud targets are significantly different. The objective of this work is to identify, analyze, and explain some of the effects of the sediment and the proximity of the seabed interface on the scattering of sound from completely and partially buried elastic shells. The analysis was performed using focused array processing of data from the GOATS98 experiment carried out jointly by MIT and SACLANTCEN, and a new hybrid modeling capability combining a virtual source-or wave-field superposition-approach with an exact spectral integral representation of the Green's functions for a stratified ocean waveguide, incorporating all multiple scattering between the object and the seabed. Among the principal results is the demonstration of the significant role of structural circumferential waves in converting incident, evanescent waves into backscattered body waves, emanating to the receivers at supercritical grazing angles, in effect making the target appear closer to the sonar than predicted by traditional ray theory. PMID:17225387

  8. Electron Elastic-Scattering Cross-Section Database

    National Institute of Standards and Technology Data Gateway

    SRD 64 NIST Electron Elastic-Scattering Cross-Section Database (PC database, no charge)   This database provides values of differential elastic-scattering cross sections, corresponding total elastic-scattering cross sections, phase shifts, and transport cross sections for elements with atomic numbers from 1 to 96 and for electron energies between 50 eV and 20,000 eV (in steps of 1 eV).

  9. Elastic scattering at 7 TeV and high-energy cross section for cosmic ray studies

    NASA Astrophysics Data System (ADS)

    Wibig, T.

    2012-08-01

    The recent measurements of the elastic cross section by the TOTEM Collaboration together with the first estimations of the inelastic cross sections by other LHC detectors are used to test the simplest version of the geometrical model of the proton-proton scattering. We show that the description found for lower energy data, with the modest adjustment of the model parameter extrapolation, could be, in principle, used to describe the LHC measurement and to predict the cross sections in very high energy cosmic ray domain. However, the shape of the first elastic dip in the elastic differential scattering cross section suggests that the ratio of the real to the imaginary part of the elastic amplitude falls rather fast and the analysis of the elastic cross-section fraction suggests that the geometrical picture and scaling of the proton-proton collision should be modified when entering the ultrahigh-energy domain.

  10. Model independent radiative corrections in processes of polarized electron-nucleon elastic scattering

    SciTech Connect

    Igor Akushevich; Andrei Afanasev; Mykola Merenkov

    2001-12-01

    The explicit formulae for radiative correction (RC) calculation for elastic ep-scattering is presented. Two typical measurements of polarization observables such as beam-target asymmetry or recoil proton polarization, are considered. Possibilities to take into account realistic experimental acceptances are discussed. The Fortran code MASCARAD for providing the RC procedure is presented. Numerical analysis is done for kinematical conditions of TJNAF.

  11. Model independent radiative corrections in processes of polarized electron-nucleon elastic scattering

    NASA Astrophysics Data System (ADS)

    Afanasev, A.; Akushevich, I.; Merenkov, N.

    2001-12-01

    Explicit formulas for radiative correction (RC) calculations for elastic ep scattering are presented. Two typical measurements of polarization observables, such as beam-target asymmetry or recoil proton polarization, are considered. The possibilities of taking into account realistic experimental acceptances are discussed. The FORTRAN code MASCARAD for providing the RC procedure is presented. A numerical analysis is done for the kinematical conditions of CEBAF.

  12. QED Radiative Corrections to Asymmetries of Elastic ep-scattering in Hadronic Variables

    SciTech Connect

    Alexander Ilyichev; Andrei Afanasev; Igor Akushevich; Mykola Merenkov

    2001-08-16

    Compact analytical formulae for QED radiative corrections in the processes of elastic e-p scattering are obtained in the case when kinematic variables are reconstructed from the recoil proton momentum measured. Numerical analysis is presented under kinematic conditions of current experiments at JLab.

  13. Coherency in neutrino-nucleus elastic scattering

    NASA Astrophysics Data System (ADS)

    Kerman, S.; Sharma, V.; Deniz, M.; Wong, H. T.; Chen, J.-W.; Li, H. B.; Lin, S. T.; Liu, C.-P.; Yue, Q.; Texono Collaboration

    2016-06-01

    Neutrino-nucleus elastic scattering provides a unique laboratory to study the quantum mechanical coherency effects in electroweak interactions, towards which several experimental programs are being actively pursued. We report results of our quantitative studies on the transitions towards decoherency. A parameter (α ) is identified to describe the degree of coherency, and its variations with incoming neutrino energy, detector threshold, and target nucleus are studied. The ranges of α that can be probed with realistic neutrino experiments are derived, indicating complementarity between projects with different sources and targets. Uncertainties in nuclear physics and in α would constrain sensitivities in probing physics beyond the standard model. The maximum neutrino energies corresponding to α >0.95 are derived.

  14. Resolving the Proton Form Factor Problem with Positron-Proton Scattering

    NASA Astrophysics Data System (ADS)

    Weinstein, Lawrence

    2012-10-01

    The proton electromagnetic form factors are essential pieces of our knowledge of nucleon structure. However, Rosenbluth separation measurements of the proton electric form factor, GE(Q^2), differ from polarization transfer measurements by a factor of three at Q^2 = 5.6 (GeV/c)^2. This discrepancy must be resolved. One possible resolution is to include the contribution of hard two-photon exchange (TPE) contributions. These contributions are very difficult to calculate. However, we can directly determine the TPE effect by measuring the ratio of the positron-proton to electron-proton elastic scattering cross sections, R=σ(e^+p)/σ(e^-p), because the TPE amplitude has the same sign as the e^+p born amplitude and the opposite sign as the e^-p born amplitude. We have measured R over a wide range of momentum transfer, 0.2 <=Q^2 <=2 GeV^2, and virtual photon polarization, 0.1 <=ɛ<=0.9, using a mixed identical beam of electrons and positrons in Hall B at Jefferson Lab. This talk will describe the experimental techniques used to produce this beam, the analysis techniques to identify elastic scattering events, and some preliminary results.

  15. 25Al+p Elastic Scattering with CRIB

    NASA Astrophysics Data System (ADS)

    Pearson, Jonty; Chen, A. A.; Kubono, S.; Yamaguchi, H.; He, J. J.; Khlem, L. H.; Salto, A.; Amadio, G.; Fajikawa, H.; Nilkura, M.; Wakabayashi, Y.; Teranishi, T.; Nishimura, S.; Togano, Y.; Odahara, A.; Moon, J. Y.; Kwon, Y. K.; Cherubini, S.; Pizzone, R.; La Cognata, M.

    The present rate of the 25 Al(p,γ)26 Si reaction suffers from significant uncertainties due to the lack of relevant structure information in the compound nucleus 26 Si. An 25 Al+p elastic-scattering experiment in inverse kinematics was performed using the CRIB facility at the CNS at the Uni- versity of Tokyo, Japan, to try and improve current understanding. The 2 H(24 Mg,n)25 Al reaction was used to produce a 7.5 MeV/A 25 Al radioactive beam with intensities of ˜ 106 pps at the secondary CH2 target position. Protons were detected in silicon E?E telescopes and a center-of- mass energy range of 3 MeV was scanned, reaching up to about 8.5 MeV in excitation energy in 26 Si.

  16. Support minimized inversion of acoustic and elastic wave scattering

    SciTech Connect

    Safaeinili, A.

    1994-04-24

    This report discusses the following topics on support minimized inversion of acoustic and elastic wave scattering: Minimum support inversion; forward modelling of elastodynamic wave scattering; minimum support linearized acoustic inversion; support minimized nonlinear acoustic inversion without absolute phase; and support minimized nonlinear elastic inversion.

  17. Coulomb effects on edge scattering in elastic nuclear collisions

    SciTech Connect

    Silveira, R. da; Leclercq-Willain, Ch.

    2011-04-15

    We present a qualitative analysis of the effects of the Coulomb force on the edge scattering produced in elastic nuclear collisions occurring under strong absorption conditions. This analysis is illustrated with several examples of nucleus-nucleus and antiproton-nucleus elastic scattering.

  18. Elastic Scattering LIDAR Data Acquisition Visualization and Analysis

    Energy Science and Technology Software Center (ESTSC)

    1999-10-12

    ELASTIC/EVIEW is a software system that controls an elastic scattering atmospheric Light Detection and Ranging (LIDAR) instrument. It can acquire elastic scattering LIDAR data using this system and produce images of one, two, and three-dimensional atmospheric data on particulates and other atmospheric pollutants. The user interface is a modern menu driven syatem with appropriate support for user configuration and printing files.

  19. Parity Violation in Proton-Proton Scattering at 47 Mev.

    NASA Astrophysics Data System (ADS)

    Tanner, Danelle Mary

    A measurement of parity-violation in proton-proton scattering at 47 MeV has been completed by observing the longitudinal analyzing power. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI). where (sigma)('+)((sigma)('-)) is the scattering cross section for positive (negative) helicity. Polarized protons from an atomic beam ion source were accelerated by the 224-cm Texas A&M University cyclotron to an energy of 50 MeV, producing a vertically polarized beam. A superconducting solenoid magnet precessed the beam polarization into the horizontal plane after which a 47.6(DEGREES) bending magnet precessed the polarization into the longtitudinal direction (p(,z) = 0.69 (+OR-) 0.02). RF transitions reversed the polarization direction every 21 msec. Protons scattered from the high pressure ((DBLTURN)37 atm), 42-cm long H(,2) gas target were detected by four plastic scintillators located in the target chamber. Photomultiplier tubes amplified the light from the scintillators, providing a signal proportional to the scattered beam intensity. A lock-in amplifier (LIA) synchronized to the spin-flip frequency compared the scattered intensity to the total beam intensity, measured with a Faraday cup. The output of the LIA was integrated for one second and then read by an ADC. Polarimeters were used to monitor both beam intensity and polarization profiles. A series of tests were performed to determine the role of spurious asymmetries due to changes in beam position and angle, and due to beam intensity modulations correlated with the spin reversal. The result after correction for beam intensity modulation was A(,z) = -(4.6 (+OR-) 2.6) x 10('-7). A more conservative result, taking into account all of the possible spurious asymmetries was A(,z) = -(4.6 (+OR-) 4.2) x 10('-7).

  20. The Proton Coulomb Form Factor from Polarized Inclusive e-p Scattering

    SciTech Connect

    Chris Harris

    2001-08-01

    The proton form factors provide information on the fundamental properties of the proton and provide a test for models based on QCD. In 1998 at Jefferson Lab (JLAB) in Newport News, VA, experiment E93026 measured the inclusive e-p scattering cross section from a polarized ammonia (15NH3) target at a four momentum transfer squared of Q2 = 0.5 (GeV/c)2. Longitudinally polarized electrons were scattered from the polarized target and the scattered electron was detected. Data has been analyzed to obtain the asymmetry from elastically scattered electrons from hydrogen in 15NH3. The asymmetry, Ap, has been used to determine the proton elastic form factor GEp. The result is consistent with the dipole model and data from previous experiments. However, due to the choice of kinematics, the uncertainty in the measurement is large.

  1. Proton spin polarizabilities from polarized Compton scattering

    SciTech Connect

    B. Pasquini; D. Drechsel; M. Vanderhaeghen

    2007-07-01

    Polarized Compton scattering off the proton is studied within the framework of subtracted dispersion relations for photon energies up to 300 MeV. As a guideline for forthcoming experiments, we focus the attention on the role of the proton's spin polarizabilities and investigate the most favorable conditions to extract them with a minimum of model dependence. We conclude that a complete separation of the four spin polarizabilities is possible, at photon energies between threshold and the $\\Delta(1232)$ region, provided one can achieve polarization measurements with an accuracy of a few percent.

  2. Positron-proton to electron-proton elastic cross section ratios from CLAS

    NASA Astrophysics Data System (ADS)

    Adikaram, Dasuni; Rimal, Dipak; Weinstein, Larry; Raue, Brian

    2014-03-01

    There is a significant discrepancy between the ratio of the electromagnetic form factors of the proton measured by the Rosenbluth and the polarization transfer technique. The most likely explanation of this discrepancy is the inclusion of two-photon exchange (TPE) amplitude contributions to the elastic electron-proton cross section. The CLAS TPE experiment measured the TPE contribution in the wide range of Q2 and ɛ range using a comparison of positron-proton to electron-proton elastic cross sections (R = σ (e+ p) / σ (e- p)). Preliminary results will be presented, along with the estimations of systematic uncertainties. A detailed comparison of new results with previous R measurements and theoretical calculations will be presented. Implications of the CLAS TPE measurements on the elastic electron-proton cross section will be also discussed.

  3. Recent results on deuteron-proton scattering from RIKEN

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Kimiko

    2016-03-01

    Nucleon-deuteron (Nd) scattering, for which a rigorous formulation in terms of Faddeev equations exists and exact solutions of these equations for any dynamical input can be obtained, offers a good opportunity to study the dynamical aspects of 3NFs, such as momentum and spin dependences. Since the first indication of 3NF effects in Nd elastic scattering around 100 MeV/nucleon, precise measurements of proton-deuteron / neutron-deuteron scattering have been extensively performed at 60-300 MeV/nucleon. Direct comparison between the data and the Faddeev calculations based on realistic nucleon-nucleon forces plus 2π-exchange three nucleon forces draws the following conclusions. (1) The 3NF is definitely needed in Nd elastic scattering. (2) The spin dependent parts of the 3NFs may be deficient. (3) The shorter-range components of the 3NFs are probably required for the cross section as well as the spin observables at backward angles with increasing an incident energy.

  4. Improved Optics For Quasi-Elastic Light Scattering

    NASA Technical Reports Server (NTRS)

    Cheung, Harry Michael

    1995-01-01

    Improved optical train devised for use in light-scattering measurements of quasi-elastic light scattering (QELS) and laser spectroscopy. Measurements performed on solutions, microemulsions, micellular solutions, and colloidal dispersions. Simultaneous measurements of total intensity and fluctuations in total intensity of light scattered from sample at various angles provides data used, in conjunction with diffusion coefficients, to compute sizes of particles in sample.

  5. A Quasi-Elastic Neutron Scattering Study of the Dynamics of Electrically Constrained Water.

    PubMed

    Fuchs, Elmar C; Bitschnau, Brigitte; Wexler, Adam D; Woisetschläger, Jakob; Freund, Friedemann T

    2015-12-31

    We have measured the quasi-elastic neutron scattering (QENS) of an electrohydrodynamic liquid bridge formed between two beakers of pure water when a high voltage is applied, a setup allowing to investigate water under high-voltage without high currents. From this experiment two proton populations were distinguished: one consisting of protons strongly bound to oxygen atoms (immobile population, elastic component) and a second one of quasi-free protons (mobile population, inelastic component) both detected by QENS. The diffusion coefficient of the quasi-free protons was found to be D = (26 ± 10) × 10(-5) cm(2) s(-1) with a jump length lav ∼ 3 Å and an average residence time of τ0 = 0.55 ± 0.08 ps. The associated proton mobility in the proton channel of the bridge is ∼9.34 × 10(-7) m(2) V(-1) s(-1), twice as fast as diffusion-based proton mobility in bulk water. It also matches the so-called electrohydrodynamic or "apparent" charge mobility, an experimental quantity which so far has lacked molecular interpretation. These results further corroborate the proton channel model for liquid water under high voltage and give new insights into the molecular mechanisms behind electrohydrodynamic charge transport phenomena and delocalization of protons in liquid water. PMID:26643863

  6. Global analysis of proton elastic form factor data with two-photon exchange corrections

    SciTech Connect

    J. Arrington; W. Melnitchouk; J. A. Tjon

    2007-09-01

    We use the world's data on elastic electron-proton scattering and calculations of two-photon exchange effects to extract corrected values of the proton's electric and magnetic form factors over the full Q^2 range of the existing data. Our analysis combines the corrected Rosenbluth cross section and polarization transfer data, and is the first extraction of G_Ep and G_Mp including explicit two-photon exchange corrections and their associated uncertainties. In addition, we examine the angular dependence of the corrected cross sections, and discuss the possible nonlinearities of the cross section as a function of epsilon.

  7. Attenuation of Elastic Waves due to Scattering from Spherical Cavities and Elastic Inclusions.

    NASA Astrophysics Data System (ADS)

    Hinders, Mark Karl

    1990-01-01

    The attenuation of elastic waves due to scattering from a spherical inclusion of arbitrary size in an infinitely extended medium is investigated. The spherical scatterer and the exterior medium are isotropic, homogeneous, and linearly elastic, but of arbitrarily differing material parameters, with compressional and shear waves supported in both media. Exact expressions for scattered and transmitted fields caused by an incident plane compressional or shear wave of unit amplitude are calculated analytically and general expressions for extinction and scattering cross -sections are derived for both lossy and lossless scattering. Application to ultrasonic determination of porosity in cast aluminum is investigated.

  8. Prospects for detecting dark matter particles by elastic scattering

    SciTech Connect

    Sadoulet, B.

    1987-02-01

    The rates, signatures, and backgrounds likely to be encountered by experiments attempting to detect dark matter particles by elastic scattering are discussed. Detector material discussed includes boron, tungsten, germanium, and silicon. 14 refs., 3 figs.

  9. The two-photon exchange contribution to elastic electron-nucleon scattering at large momentum transfer

    SciTech Connect

    Andrei V. Afanasev; Stanley J. Brodsky; Carl E. Carlson; Yu-Chun Chen; Marc Vanderhaeghen

    2005-01-01

    We estimate the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer by using a quark-parton representation of virtual Compton scattering. We thus can relate the two-photon exchange amplitude to the generalized parton distributions which also enter in other wide angle scattering processes. We find that the interference of one- and two-photon exchange contribution is able to substantially resolve the difference between electric form factor measurements from Rosenbluth and polarization transfer experiments.

  10. On the Large-t Elastic Scattering at √{s} = 7 TeV

    NASA Astrophysics Data System (ADS)

    Troshin, S. M.; Tyurin, N. E.

    2012-06-01

    We discuss discrimination of the scattering mechanisms on the basis of functional dependencies of the large-t elastic scattering suggested by the recent data from the TOTEM experiment. It is shown that Orear exponent is in a better agreement with the data than the power-like dependence used by the TOTEM. This implies that the collective dynamics is dominating over the point-like mechanism related to the scattering of the proton constituents. We also emphasize that vanishing of the helicity-flip amplitudes contributions at the LHC energies would result in appearance of the dip-bump structures at higher values of transferred momenta.

  11. An Examination of Proton Charge Radius Extractions from e–p Scattering Data

    SciTech Connect

    Arrington, John

    2015-09-15

    A detailed examination of issues associated with proton radius extractions from elastic electron–proton scattering experiments is presented. Sources of systematic uncertainty and model dependence in the extractions are discussed, with an emphasis on how these may impact the proton charge and magnetic radii. A comparison of recent Mainz data to previous world data is presented, highlighting the difference in treatment of systematic uncertainties as well as tension between different data sets. We find several issues that suggest that larger uncertainties than previously quoted may be appropriate, but do not find any corrections which would resolve the proton radius puzzle.

  12. An Examination of Proton Charge Radius Extractions from e-p Scattering Data

    NASA Astrophysics Data System (ADS)

    Arrington, John

    2015-09-01

    A detailed examination of issues associated with proton radius extractions from elastic electron-proton scattering experiments is presented. Sources of systematic uncertainty and model dependence in the extractions are discussed, with an emphasis on how these may impact the proton charge and magnetic radii. A comparison of recent Mainz data to previous world data is presented, highlighting the difference in treatment of systematic uncertainties as well as tension between different data sets. We find several issues that suggest that larger uncertainties than previously quoted may be appropriate, but do not find any corrections which would resolve the proton radius puzzle.

  13. Proton radius from electron scattering data

    NASA Astrophysics Data System (ADS)

    Higinbotham, Douglas W.; Kabir, Al Amin; Lin, Vincent; Meekins, David; Norum, Blaine; Sawatzky, Brad

    2016-05-01

    Background: The proton charge radius extracted from recent muonic hydrogen Lamb shift measurements is significantly smaller than that extracted from atomic hydrogen and electron scattering measurements. The discrepancy has become known as the proton radius puzzle. Purpose: In an attempt to understand the discrepancy, we review high-precision electron scattering results from Mainz, Jefferson Lab, Saskatoon, and Stanford. Methods: We make use of stepwise regression techniques using the F test as well as the Akaike information criterion to systematically determine the predictive variables to use for a given set and range of electron scattering data as well as to provide multivariate error estimates. Results: Starting with the precision, low four-momentum transfer (Q2) data from Mainz (1980) and Saskatoon (1974), we find that a stepwise regression of the Maclaurin series using the F test as well as the Akaike information criterion justify using a linear extrapolation which yields a value for the proton radius that is consistent with the result obtained from muonic hydrogen measurements. Applying the same Maclaurin series and statistical criteria to the 2014 Rosenbluth results on GE from Mainz, we again find that the stepwise regression tends to favor a radius consistent with the muonic hydrogen radius but produces results that are extremely sensitive to the range of data included in the fit. Making use of the high-Q2 data on GE to select functions which extrapolate to high Q2, we find that a Padé (N =M =1 ) statistical model works remarkably well, as does a dipole function with a 0.84 fm radius, GE(Q2) =(1+Q2/0.66 GeV2) -2 . Conclusions: Rigorous applications of stepwise regression techniques and multivariate error estimates result in the extraction of a proton charge radius that is consistent with the muonic hydrogen result of 0.84 fm; either from linear extrapolation of the extremely-low-Q2 data or by use of the Padé approximant for extrapolation using a larger

  14. 12C+p resonant elastic scattering in the Maya active target

    NASA Astrophysics Data System (ADS)

    Sambi, S.; Raabe, R.; Borge, M. J. G.; Caamano, M.; Damoy, S.; Fernández-Domínguez, B.; Flavigny, F.; Fynbo, H.; Gibelin, J.; Grinyer, G. F.; Heinz, A.; Jonson, B.; Khodery, M.; Nilsson, T.; Orlandi, R.; Pancin, J.; Perez-Loureiro, D.; Randisi, G.; Ribeiro, G.; Roger, T.; Suzuki, D.; Tengblad, O.; Thies, R.; Datta, U.

    2015-03-01

    In a proof-of-principle measurement, the Maya active target detector was employed for a 12C( p, p) resonant elastic scattering experiment in inverse kinematics. The excitation energy region from 0 to 3MeV above the proton breakup threshold in 13N was investigated in a single measurement. By using the capability of the detector to localize the reaction vertex and record the tracks of the recoiling protons, data covering a large solid angle could be utilized, at the same time keeping an energy resolution comparable with that of direct-kinematics measurements. The excitation spectrum in 13N was fitted using the R-matrix formalism. The level parameters extracted are in good agreement with previous studies. The active target proved its potential for the study of resonant elastic scattering in inverse kinematics with radioactive beams, when detection efficiency is of primary importance.

  15. Quasi-elastic neutron scattering studies of protein dynamics

    SciTech Connect

    Rorschach, H.E.

    1993-05-25

    Results that shed new light on the study of protein dynamics were obtained by quasi-elastic neutron scattering. The triple axis instrument H-9 supplied by the cold source was used to perform a detailed study of the quasi-elastic spectrum and the Debye-Waller factor for trypsin in powder form, in solution, and in crystals. A preliminary study of myoglobin crystals was also done. A new way to view the results of quasi-elastic scattering experiments is sketched, and the data on trypsin are presented and analyze according to this new picture.

  16. Test of 600 and 750 MeV NN matrix on elastic scattering Glauber model calculations

    NASA Astrophysics Data System (ADS)

    Brissaud, I.

    1980-09-01

    The 600 and 750 MeV proton nucleus elastic scattering cross section and polarization calculations have been performed in the framework of the Glauber model to test the pp and pn scattering amplitudes deduced from a phase shift analysis by Bystricky, Lechanoine and Lehar. It is well known that up to now we do not possess a non-phenomenological NN scattering matrix at intermediate energies. However proton-nucleus scattering analyses are used to extract information about short range correlations1), Δ resonance2) or pion condensation presences)... etc. Most scattering calculations made at these energies have been done with phenomenological NN amplitudes having a gaussian q-dependence 10050_2005_Article_BF01438168_TeX2GIFE1.gif A(q) = {kσ }/{4π }(α + i) e^{ - β ^2 q^2 /2} and 10050_2005_Article_BF01438168_TeX2GIFE2.gif C(q) = {kσ }/{4π }iq(α + i) D_e - β ^2 q^2 /2 K and σ being respectively the projectile momentum and the total pN total cross section. The parameters α, β and D are badly known and are adjusted by fitting some specific reactions as p+4He elastic scattering4). Even when these amplitudes provide good fits to the data, our understanding of the dynamics of the scattering remains obscure.

  17. rvec p + sup 13 rvec C elastic scattering at 500 MeV

    SciTech Connect

    Tanaka, N.

    1990-01-01

    For the first time, an elastic scattering experiment was performed at LAMPF using polarized protons and a polarized target nucleus ({rvec p} + {sup 13}{rvec C}). The analyzing powers (A{sub ooon}({Theta})) and (A{sub oonn}({Theta})) were measured using an incident beam energy of 500 MeV over the laboratory angular range of 10{degree}--30{degree}. Motivation for the experiment and some preliminary results and conclusions are presented. 12 refs., 7 figs.

  18. Quasi-elastic nuclear scattering at high energies

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.

    1992-01-01

    The quasi-elastic scattering of two nuclei is considered in the high-energy optical model. Energy loss and momentum transfer spectra for projectile ions are evaluated in terms of an inelastic multiple-scattering series corresponding to multiple knockout of target nucleons. The leading-order correction to the coherent projectile approximation is evaluated. Calculations are compared with experiments.

  19. Effects of Auger electron elastic scattering in quantitative AES

    NASA Astrophysics Data System (ADS)

    Jablonski, Aleksander

    1987-09-01

    The Monte Carlo algorithm was developed for simulating the trajectories of electrons elastically scattered in the solid. The distribution of scattering angles was determined using the partial wave expansion method. This algorithm was used to establish the influence of Auger electron elastic collisions on the results of quantitative AES analysis. The calculations were performed for the most pronounced KLL, L 3 MM and M 5NN Auger transitions. It turned out that due to the elastic collisions the Auger electron signal is decreased by up to 10%. The corresponding decreased of the escape depth of Auger electrons reaches 30% as compared with the value derived from the inelastic mean free path. The values of the inelastic mean free path resulting from the overalyer method may be strongly affected by elastic scattering of Auger electrons.

  20. Inelastic Scattering Of Electrons By Protons

    DOE R&D Accomplishments Database

    Cone, A. A.; Chen, K. W.; Dunning, J. R. Jr.; Hartwig, G.; Ramsey, N. F.; Walker, J. K.; Wilson, R.

    1966-12-01

    The inelastic scattering of electrons by protons has been measured at incident electron energies up to 5 BeV/c and momentum transfers q{sup 2}=4(BeV/c){sup 2}. Excitation of known nucleon resonances at M=1238, 1512, 1688 and possibly 1920 MeV have been observed. The calculations for the resonance at M=1238 MeV have been compared with calculations by Adler based on the dispersion theory of Chew, Goldberger, Low and Nambu. The agreement is good. Qualitative models are discussed for the other resonances.

  1. Measuring the 2{gamma} Exchange Effect in Electron-Proton Scattering at CLAS

    SciTech Connect

    Bennett, Robert Paul

    2011-10-24

    Recent results from experiments at Jefferson Laboratory, Newport News VA, which measure the ratio of the electric to magnetic form factors of the proton, G{sub E}/G{sub M}, have forced us to reexamine the single photon exchange approximation in lepton-proton elastic scattering. Discrepancies between the ratio obtained via the time-tested Rosenbluth separation method and new polarization transfer measurements, which differ by as much as a factor of three, may be resolved by considering the effect of two photon exchange (TPE). Theoretical corrections for the TPE effect are difficult due to the large number of excited nucleon states that can contribute to the process. The TPE effect can, however, be determined directly by measuring the ratio of the positron-proton to electron-proton elastic scattering cross sections, R = {sigma}(e{sup +})/{sigma}(e{sup -}), since the TPE effect changes sign with the charge of the incident particle. The CLAS TPE experiment at Jefferson Laboratory, will determine the effect of two-photon exchange in elastic lepton-proton scattering by precisely measuring the ratio of positron-proton to electron-proton elastic cross sections over a large kinematic range (0.1<{epsilon}<0.96, 0.02{<=}Q{sup 2}{<=}2.0). We will accomplish this by directing the 5.5 GeV primary electron beam, provided by the Continuous Electron Beam Accelerator Facility (CEBAF), onto a set of radiators and converters to produce simultaneous and identical beams of electron and positrons. Acceptance and efficiency concerns are minimized by only considering the ratios of the elastic cross sections and switching polarity of magnets in the beam line and the spectrometer. Guided by the results of a short 2006 test run and extensive GEANT based modeling, new shielding and beam line components were designed to maximize luminosity. The unique experimental design and challenges of the TPE experiment and the projected luminosities will be presented.

  2. Elastic scattering by finitely many point-like obstacles

    NASA Astrophysics Data System (ADS)

    Hu, Guanghui; Sini, Mourad

    2013-04-01

    This paper is concerned with the time-harmonic elastic scattering by a finite number N of point-like obstacles in {{R}}^n (n = 2, 3). We analyze the N-point interactions model in elasticity and derive the associated Green's tensor (integral kernel) in terms of the point positions and the scattering coefficients attached to them, following the approach in quantum mechanics for modeling N-particle interactions. In particular, explicit expressions are given for the scattered near and far fields corresponding to elastic plane waves or point-source incidences. As a result, we rigorously justify the Foldy method for modeling the multiple scattering by finitely many point-like obstacles for the Lamé model. The arguments are based on the Fourier analysis and the Weinstein-Aronszajn inversion formula of the resolvent for the finite rank perturbations of closed operators in Hilbert spaces.

  3. Experimental study of quasi-elastic scattering of ultracold neutrons

    NASA Astrophysics Data System (ADS)

    Steyerl, A.; Yerozolimsky, B. G.; Serebrov, A. P.; Geltenbort, P.; Achiwa, N.; Pokotilovski, Yu. N.; Kwon, O.; Lasakov, M. S.; Krasnoshchokova, I. A.; Vasilyev, A. V.

    2002-08-01

    Ultracold neutrons (UCN) are lost from traps if they are quasi-elastically scattered from the wall with an energy gain sufficient to exceed the Fermi potential for the wall. Possible mechanisms of a quasi-elastic energy transfer are, for instance, scattering from hydrogen diffusing in an impurity surface layer or on surface waves at a liquid wall. Using two different experimental methods at the UCN source of the Institut Laue-Langevin we have investigated both the energy-gain and the energy-loss side of quasi-elastic UCN scattering on Fomblin grease coated walls. For Fomblin oil and similar new types of oil we report up-scattering data as a function of temperature and energy transfer. These low-temperature oils may be used in an improved measurement of the neutron lifetime, which requires extremely low wall reflection losses.

  4. Electron impact elastic scattering and vibrational excitation of ethylene

    NASA Astrophysics Data System (ADS)

    Khakoo, Murtadha; Khakoo, Sabaha; Sakaamini, Ahmad; Hargreaves, Leigh; Winstead, Carl; McKoy, Vince

    2015-09-01

    Experimental and theoretical (Schwinger Multi-Channel model) differential scattering cross sections for low energy electron elastic scattering plus vibrational excitation (4 energy loss features) of ethylene are presented. The incident electron energy range is from 0.5eV to 100eV and scattering angles of 5 to 130 degrees. Comparisons with theory and past available measurements show good agreement in general. Funded by a National Science Foundation Collaborative Research Grant to CSUF and Caltech.

  5. Target-charge dependence of the breakup coupling effects in the elastic scattering of 8B

    NASA Astrophysics Data System (ADS)

    Kucuk, Y.; Aciksoz, E.

    2016-04-01

    We perform continuum discretized coupled-channels calculations for the elastic scattering of 8B on different targets to trace where the Coulomb-nuclear breakup coupling effects start to be dominant in the interaction of the proton halo nuclei. We observe a qualitative difference in angular distributions when the charge of the target increases as seen in the case of neutron halos, but the Coulomb-nuclear interference peak begins to disappear clearly at a relatively smaller value of Z T for the proton halos.

  6. Elastic neutrino electron scattering at Brookhaven

    SciTech Connect

    Cutts, D.

    1984-01-01

    A progress report is given of Experiment 734 at Brookhaven, with a focus on the elastic reactions nu/sub ..mu../ + e/sup -/ ..-->.. nu/sub ..mu../ + e/sup -/ and anti nu/sub ..mu../ + e/sup -/ ..-->.. anti nu/sub ..mu../ + e/sup -/. The present status, recent results, and future plans are discussed.

  7. Ay Measurement in p→p-Elastic Scattering at Small Angles

    NASA Astrophysics Data System (ADS)

    Macharashvili, G.

    2016-02-01

    The proton analysing power in p→p elastic scattering has been measured at small angles at COSY-ANKE at 796MeV and five other beam energies between 1.6 and 2.4GeV using a polarized proton beam. The asymmetries obtained by detecting the fast proton in the ANKE forward detector or the slow recoil proton in a silicon tracking telescope are completely consistent. The sources of the systematic uncertainties and the time stability issue were considered. The ANKE data at the higher energies lie well above the predictions of the most recent partial wave solution at small angles. An updated phase shift analysis that uses the ANKE results together with the World data leads to a better description of these new measurements.

  8. Absolute Beam Energy Measurement using Elastic ep Scattering at Thomas Jefferson National Accelerator Facility

    NASA Astrophysics Data System (ADS)

    Deur, Alexandre

    1999-10-01

    The Jefferson Lab beam energy measurement in Hall A using the elastic ep scattering will be described. This new, non-magnetic, energy measurement method allows a ( triangle E/E=10-4 ) precision. First-order corrections are canceled by the measurements of the electron and proton scattering angles for two symmetric kinematics. The measurement principle will be presented as well as the device and measurement results. Comparison with independent magnetic energy measurements of the same accuracy will be shown. This project is the result of a collaboration between the LPC: université Blaise Pascal/in2p3), Saclay and Jefferson Lab.

  9. Elastic electron scattering from formic acid

    SciTech Connect

    Trevisan, Cynthia S.; Orel, Ann E.; Rescigno, Thomas N.

    2006-07-31

    Following our earlier study on the dynamics of low energy electron attachment to formic acid, we report the results of elastic low-energy electron collisions with formic acid. Momentum transfer and angular differential cross sections were obtained by performing fixed-nuclei calculations employing the complex Kohn variational method. We make a brief description of the technique used to account for the polar nature of this polyatomic target and compare our results with available experimental data.

  10. Weak charge of the proton: loop corrections to parity-violating electron scattering

    SciTech Connect

    Wally Melnitchouk

    2011-05-01

    I review the role of two-boson exchange corrections to parity-violating elastic electron–proton scattering. Direct calculations of contributions from nucleon and Delta intermediate states show generally small, [script O](1–2%), effects over the range of kinematics relevant for proton strangeness form factor measurements. For the forward angle Qweak experiment at Jefferson Lab, which aims to measure the weak charge of the proton, corrections from the gammaZ box diagram are computed within a dispersive approach and found to be sizable at the E~1 GeV energy scale of the experiment.

  11. Elastic and inelastic scattering of He atoms from Bi(111)

    NASA Astrophysics Data System (ADS)

    Tamtögl, A.; Mayrhofer-Reinhartshuber, M.; Balak, N.; Ernst, W. E.; Rieder, K. H.

    2010-08-01

    Elastic and inelastic scattering of helium atoms has been used to study the Bi(111) surface. Sharp diffraction peaks are found with results in excellent agreement with previous structure determinations of the Bi(111) surface. The rather large first order peaks with respect to the zero order peak indicate a stronger surface corrugation than observed in helium scattering from other metallic surfaces. Time-of-flight spectra of scattered He atoms clearly reveal two inelastic scattering maxima, which allow a first report on phonon creation and annihilation events on the Bi(111) surface. An estimate of the group velocity shows that the phonon creation peak is likely to correspond to a Rayleigh mode.

  12. Checks of asymptotia in pp elastic scattering at LHC

    NASA Astrophysics Data System (ADS)

    Grau, Agnes; Pacetti, Simone; Pancheri, Giulia; Srivastava, Yogendra N.

    2012-07-01

    We parametrize TOTEM data for the elastic differential pp cross section at √{s}=7 TeV in terms of two exponentials with a relative phase. We employ two previously derived sum rules for pp elastic scattering amplitude in impact parameter space to check whether asymptotia has been reached at the LHC. A detailed study of the TOTEM data for the elastic differential cross section at √{s}=7 TeV is made and it is shown that, within errors, the asymptotic sum rules are satisfied at LHC. We propose to use this parametrization to study forthcoming higher energy data.

  13. The First Measurement of the Elastic pp-scattering Spin Parameters at {radical}(s) = 200 GeV

    SciTech Connect

    Bueltmann, S.; Chiang, I. H.; Chrien, R. E.; Drees, A.; Gill, R. L.; Guryn, W.; Landgraf, J.; Ljubicic, T. A.; Lynn, D.; Pearson, C.; Pile, P.; Rusek, A.; Sakitt, M.; Tepikian, S.; Yip, K.; Chwastowski, J.; Pawlik, B.; Haguenauer, M.; Bogdanov, A. A.; Nurushev, S. B.

    2007-06-13

    Elastic scattering of polarized protons in the range of very small momentum transferred was studied for the first time at {radical}(s) = 200 GeV in the experiment pp2pp at RHIC. This article presents the single spin asymmetry A{sub N} and the double spin asymmetries A{sub NN} and A{sub SS} measured in this experiment.

  14. Elastic scattering of electrons from Rb, Cs and Fr atoms

    NASA Astrophysics Data System (ADS)

    Gangwar, R. K.; Tripathi, A. N.; Sharma, L.; Srivastava, R.

    2010-04-01

    Differential, integrated elastic, momentum-transfer and total cross sections as well as differential S, T and U spin parameters for scattering of electrons from rubidium, caesium and francium atoms in the incident energy range up to 300 eV are calculated using a relativistic Dirac equation. The projectile electron-target atom interaction is represented by both real and complex parameter-free optical potentials for obtaining the solution of a Dirac equation for scattered electrons. The Dirac-Fock wavefunctions have been used to represent the Rb, Cs and Fr target atoms. The results of differential cross sections and spin asymmetry parameter S for e-Rb and e-Cs have been compared with the available experimental and theoretical results. Detailed results are reported for the elastic scattering of electrons from the ground states of a francium atom for the first time in the wide range of incident electron energies. The results of electron-Fr elastic scattering show the similar features to those obtained in the case of e-Rb and e-Cs elastic scattering.

  15. Energy distribution of elastically scattered electrons from double layer samples

    NASA Astrophysics Data System (ADS)

    Tőkési, K.; Varga, D.

    2016-02-01

    We present a theoretical description of the spectra of electrons elastically scattered from thin double layered Au-C samples. The analysis is based on the Monte Carlo simulation of the recoil and Doppler effects in reflection and transmission geometries of the scattering at a fixed angle of 44.3 ° and a primary energy of 40 keV. The relativistic correction is taken into account. Besides the experimentally measurable energy distributions the simulations give many partial distributions separately, depending on the number of elastic scatterings (single, and multiple scatterings of different types). Furthermore, we present detailed analytical calculations for the main parameters of the single scattering, taking into account both the ideal scattering geometry, i.e. infinitesimally small angular range, and the effect of the real, finite angular range used in the measurements. We show our results for intensity ratios, peak shifts and broadenings for four cases of measurement geometries and layer thicknesses. While in the peak intensity ratios of gold and carbon for transmission geometries were found to be in good agreement with the results of the single scattering model, especially large deviations were obtained in reflection geometries. The separation of the peaks, depending on the geometry and the thickness, generally smaller, and the peak width generally larger than it can be expected from the nominal values of the primary energy, scattering angle, and mean kinetic energy of the atoms. We also show that the peaks are asymmetric even for the case of the single scattering due to the finite solid angle. Finally, we present a qualitative comparison with the experimental data. We find our resulting energy distribution of elastically scattered electrons to be in good agreement with recent measurements.

  16. Contraband detection via neutron elastic scattering

    SciTech Connect

    Gomberg, H.J.; Charatis, G.; Brundage, J.

    1993-04-01

    Reliable detection of explosives and narcotics depends on generating signatures of compounds which characterize them. Major explosives and also alkaloid narcotics contain unique concentrations of Carbon (C), Nitrogen (N), and Oxygen (O). The kinematic energy shifts of neutrons scattered through angles larger than 140{degrees} allows separate determinations of C, N, and O; ratios of N/C and O/C together give clear signatures of the presence of plastic explosives or narcotics. The ability to detect these signatures under conditions similar to those that would obtain for airport screening has been demonstrated for neutrons for energies less {le} 3 MeV. Strong N resonances and a deep window for scattering from O enhance the confidence of element quantification. Detection of contraband in large cargo containers presents a much more difficult problem. Use of higher energy neutrons is now being tested for shielding penetration, so narcotic signatures could be identified behind the shielding of cargo containers. Scattered neutron spectra, or {open_quotes}signatures{close_quotes} of different organic compounds will be presented.

  17. High energy parton-parton elastic scattering in QCD

    SciTech Connect

    Tang, W.K.

    1993-08-01

    We show that the high energy limit of quark-quark, or gluon-gluon, elastic scattering is calculable in terms of the BFKL pomeron when {minus}t {much_gt} {Lambda}{sub QCD}{sup 2}. Surprisingly, this on-shell amplitudes does not have infrared divergences in the high energy limit.

  18. Elastic scattering of e- and e+ from Rb and Cd

    NASA Technical Reports Server (NTRS)

    Pangantiwar, A. W.; Srivastava, Rajesh

    1990-01-01

    Differential cross section results are calculated for the elastic scattering of electrons and positrons from the ground state of Rb and Cd atoms. An optical model potential approach is used for the calculation. Results are compared with the available electron impact experimental results.

  19. Avalanche proton-boron fusion based on elastic nuclear collisions

    NASA Astrophysics Data System (ADS)

    Eliezer, Shalom; Hora, Heinrich; Korn, Georg; Nissim, Noaz; Martinez Val, Josè Maria

    2016-05-01

    Recent experiments done at Prague with the 600 J/0.2 ns PALS laser interacting with a layer of boron dopants in a hydrogen enriched target have produced around 109 alphas. We suggest that these unexpected very high fusion reactions of proton with 11B indicate an avalanche multiplication for the measured anomalously high nuclear reaction yields. This can be explained by elastic nuclear collisions in the broad 600 keV energy band, which is coincident with the high nuclear p-11B fusion cross section, by the way of multiplication through generation of three secondary alpha particles from a single primarily produced alpha particle.

  20. Rayleigh scattering and nonlinear inversion of elastic waves

    SciTech Connect

    Gritto, R.

    1995-12-01

    Rayleigh scattering of elastic waves by an inclusion is investigated and the limitations determined. In the near field of the inhomogeneity, the scattered waves are up to a factor of 300 stronger than in the far field, excluding the application of the far field Rayleigh approximation for this range. The investigation of the relative error as a function of parameter perturbation shows a range of applicability broader than previously assumed, with errors of 37% and 17% for perturbations of {minus}100% and +100%, respectively. The validity range for the Rayleigh limit is controlled by large inequalities, and therefore, the exact limit is determined as a function of various parameter configurations, resulting in surprisingly high values of up to k{sub p}R = 0.9. The nonlinear scattering problem can be solved by inverting for equivalent source terms (moments) of the scatterer, before the elastic parameters are determined. The nonlinear dependence between the moments and the elastic parameters reveals a strong asymmetry around the origin, which will produce different results for weak scattering approximations depending on the sign of the anomaly. Numerical modeling of cross hole situations shows that near field terms are important to yield correct estimates of the inhomogeneities in the vicinity of the receivers, while a few well positioned sources and receivers considerably increase the angular coverage, and thus the model resolution of the inversion parameters. The pattern of scattered energy by an inhomogeneity is complicated and varies depending on the object, the wavelength of the incident wave, and the elastic parameters involved. Therefore, it is necessary to investigate the direction of scattered amplitudes to determine the best survey geometry.

  1. Measurement of the Wolfenstein parameters for proton-proton and proton-neutron scattering at 500 MeV

    SciTech Connect

    Marshall, J.A.

    1984-07-01

    Using liquid hydrogen and liquid deuterium targets respectively, forward angle (ten degrees to sixty degrees in the center of Mass) free proton-proton and quasielastic proton-proton and proton-neutron triple scattering data at 500 MeV have been obtained using the high resolution spectrometer at the Los Alamos Meson Physics Facility. The data are in reasonable agreement with recent predictions from phase shift analyses, indicating that the proton-nucleon scattering amplitudes are fairly well determined at 500 MeV. 32 references.

  2. Amplitude description of elastic pp scattering at 800 MeV

    NASA Astrophysics Data System (ADS)

    Moravcsik, Michael J.; Arash, Firooz; Goldstein, Gary R.

    1985-04-01

    Recent polarization data on proton-proton elastic scattering at 800 MeV taken at LAMPF are used for an amplitude analysis using the optimal formalism. The direct analysis of data is done in the transversity frame, which is best suited to parity-conserving reactions. From the results, amplitudes are also obtained in the helicity frame and the ``magic'' frame. Agreement with previous amplitudes obtained from an energy-dependent phase-shift analysis is good. The comparison of the helicity amplitudes c and e strengthens previous suggestions for a possible triplet-state dibaryon resonance. The comparison of the amplitudes am and cm in the magic frame indicates a possible domination of the process near 90° scattering angle by one-particle-exchange mechanism involving exchanged particles with natural parity.

  3. Elastic positron-cadmium scattering at low energies

    SciTech Connect

    Bromley, M. W. J.; Mitroy, J.

    2010-05-15

    The elastic and annihilation cross sections for positron-cadmium scattering are reported up to the positronium-formation threshold (at 2.2 eV). The low-energy phase shifts for the elastic scattering of positrons from cadmium were derived from the bound and pseudostate energies of a very large basis configuration-interaction calculation of the e{sup +}-Cd system. The s-wave binding energy is estimated to be 126{+-}42 meV, with a scattering length of A{sub scat}=(14.2{+-}2.1)a{sub 0}, while the threshold annihilation parameter, Z{sub eff}, was 93.9{+-}26.5. The p-wave phase shift exhibits a weak shape resonance that results in a peak Z{sub eff} of 91{+-}17 at a collision energy of about 490{+-}50 meV.

  4. Nuclear rainbow in elastic scattering of {sup 9}Be nuclei

    SciTech Connect

    Glukhov, Yu. A. Ogloblin, A. A.; Artemov, K. P.; Rudakov, V. P.

    2010-01-15

    A systematic investigation of the elastic scattering of the {sup 9}Be nucleus, which is among themost loosely bound stable nuclei was performed.Differential cross sections for elastic {sup 9}Be + {sup 16}O scattering were measured at a c.m. energy of 47.5 MeV (beam of 132-MeV {sup 16}O nuclei). Available data at different energy values and data for neighboring nuclei were included in our analysis. As a result, the very fact of rainbow scattering was reliably established for the first time in systems involving {sup 9}Be. In addition, the analysis in question made it possible to identify Airy minima and to determine unambiguously the nucleus-nucleus potential with a high probability.

  5. Microcalcifications as elastic scatterers under ultrasound.

    PubMed

    Anderson, M E; Soo, M C; Trahey, G E

    1998-01-01

    One of the fundamental limitations of medical ultrasound in the imaging of the breast is the inability of current practice to reliably visualize microcalcifications in the size range of clinical interest. Microcalcifications (MCs) are small crystals of calcium phosphates that form in human tissue through a number of mechanisms. The size, morphology, and distribution of MCs are important indicators in the mammographic screening for and diagnosis of various carcinomas in the breast. The authors are investigating the imaging of MCs under ultrasound in the interest of extending the utility of medical ultrasound in the breast clinic. They present an analysis of the acoustic properties of MCs modeled as elastic spheres based on the Faran model that considers the predicted complex spectra and spatial coherence of echoes from MCs. They have found the predictions of the model to be similar to ultrasound echoes from suspected MCs in vivo. They also present breast phase aberration estimates and spatial and frequency compounding results based on the echoes from these targets. PMID:18244247

  6. Measurements of the Proton Electromagnetic Form Factor Ratio From Elastic e + p -> e + p Scattering at Momentum Transfer Q2 = 2.5, 5.2, 6.7 and 8.5 (GeV/c)2

    SciTech Connect

    Mkrtchyan, Arthur

    2012-05-31

    Among the fundamental observables of nucleon structure, electromagnetic form factors are a crucial benchmark for modern calculations describing the strong interaction dynamics of the nucleon's quark constituents. Electromagnetic probes are traditionally preferered to the hadronic beams. The electromagnetic interaction is a powerful tool for investigating the nucleon structure since it is well understood and it reveals observables that can be directly interpreted in terms of the current carried by the quarks. Elastic scattering leads to the form factors that describe the spatial charge and current distributions inside the nucleon. The reaction mechanism is assumed to be one photon exchange, the electromagnetic interaction is exactly calculable in QED, and one can safely extract the information on the hadronic vertex. The most important feature of early measurements of proton form factor ratio GEp/GMp with recoil polarization technique at Q2 up to 5.6 (GeV/c)2 is the sharp decline of the ratio with Q2 increases, indicating that GEp falls much faster than GMp. This contradicts to data obtained by Rosenbluth separation method. An intriguing question was whether GEp will continue to decrease or become constant when Q2 increases. New set of measurements of proton form factor ratio GEp/GMp at Q2 = 2.5, 5.2, 6.7 and 8.5 (GeV/c)2 have been conducted at JLab Hall C using ~85% longitudinally polarized electron elastic scattering from unpolarized hydrogen target. Recoil protons were detected in the HMS magnetic spectrometer with the standard detector package, combined with newly installed trigger scintillators and Focal Plane Polarimeter. The BigCal electromagnetic calorimeter (1744 channel) have been used for electron detection. Data obtained in this

  7. Investigation of color transparency by high transverse momentum pp elastic scattering inside nuclei

    SciTech Connect

    Barton, D.S.; Bunce, G.; Carroll, A.S.; Gushue, S.; Makdisi, Y.I.; Heppelmann, S.; Courant, H.; Fang, G.Y.; Heller, K.J.; Marshak, M.L.

    1989-01-01

    Following a suggestion of Mueller and Brodsky, we have measured (p, 2p) quasielastic scattering in nuclei at 90(degree) CM at momentum transfers of Q/sup 2/ = 4.8, 8.5 and 10.4 (GeV/c)/sup 2/. In a perturbative QCD model of large transverse momentum exclusive reactions, the hadrons which scatter are anomalously ''small,'' and hence have a reduced absorption in nuclear matter over distances comparable to nuclear radii. At sufficiently high momentum, the absorption should vanish completely and lead to complete ''color transparency.'' The absorption of the initial and final state protons as they pass through nuclear matter is determined from the ratio of the differential cross section for elastic scattering from protons in nuclei to that from free protons. The kinematic constraints of the experiment allow a clear extraction of the (p,2p) quasielastic signal, and a good measurement of the target proton momentum spectrum as probed by large momentum transfers. In contrast to a conventional Glauber picture of constant transparency, a striking energy dependence is observed in this experiment. 11 refs., 4 figs.

  8. Low-Energy Elastic Electron Scattering by Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Zatsarinny O.; Bartschat, K.; Tayal, S. S.

    2006-01-01

    The B-spline R-matrix method is employed to investigate the low-energy elastic electron scattering by atomic oxygen. Flexible non-orthogonal sets of radial functions are used to construct the target description and to represent the scattering functions. A detailed investigation regarding the dependence of the predicted partial and total cross sections on the scattering model and the accuracy of the target description is presented. The predicted angle-integrated elastic cross sections are in good agreement with experiment, whereas significant discrepancies are found in the angle-differential elastic cross sections near the forward direction. .The near-threshold results are found to strongly depend on the treatment of inner-core short-range correlation effects in the target description, as well as on a proper account of the target polarizability. A sharp increase in the elastic cross sections below 1 eV found in some earlier calculations is judged to be an artifact of an unbalanced description of correlation in the N-electron target structure and the (N+l)-electron-collision problems.

  9. Semiphenomenological method of analysis for intermediate-energy alpha-nucleus elastic scattering data

    SciTech Connect

    Ahmad, I.; Alvi, M.A.

    1983-12-01

    We propose a semiphenomenological method of analysis for intermediate energy ..cap alpha..-nucleus elastic scattering experiments and demonstrate its usefulness by analyzing available elastic ..cap alpha..-nucleus scattering data at 1.37 GeV.

  10. Measurement of Neutrino-Nucleon Neutral-Current Elastic Scattering Cross-section at SciBooNE

    SciTech Connect

    Takei, Hideyuki; /Tokyo Inst. Tech.

    2009-02-01

    In this thesis, results of neutrino-nucleon neutral current (NC) elastic scattering analysis are presented. Neutrinos interact with other particles only with weak force. Measurement of cross-section for neutrino-nucleon reactions at various neutrino energy are important for the study of nucleon structure. It also provides data to be used for beam flux monitor in neutrino oscillation experiments. The cross-section for neutrino-nucleon NC elastic scattering contains the axial vector form factor G{sub A}(Q{sup 2}) as well as electromagnetic form factors unlike electromagnetic interaction. G{sub A} is propotional to strange part of nucleon spin ({Delta}s) in Q{sup 2} {yields} 0 limit. Measurement of NC elastic cross-section with smaller Q{sup 2} enables us to access {Delta}s. NC elastic cross-sections of neutrino-nucleon and antineutrino-nucleon were measured earlier by E734 experiment at Brookheaven National Laboratory (BNL) in 1987. In this experiment, cross-sections were measured in Q{sup 2} > 0.4 GeV{sup 2} region. Result from this experiment was the only published data for NC elastic scattering cross-section published before our experiment. SciBooNE is an experiment for the measurement of neutrino-nucleon scattering cross-secitons using Booster Neutrino Beam (BNB) at FNAL. BNB has energy peak at 0.7 GeV. In this energy region, NC elastic scattering, charged current elastic scattering, charged current pion production, and neutral current pion production are the major reaction branches. SciBar, electromagnetic calorimeter, and Muon Range Detector are the detectors for SciBooNE. The SciBar consists of finely segmented scintillators and 14336 channels of PMTs. It has a capability to reconstruct particle track longer than 8 cm and separate proton from muons and pions using energy deposit information. Signal of NC elastic scattering is a single proton track. In {nu}p {yields} {nu}p process, the recoil proton is detected. On the other hand, most of {nu}n {yields} {nu

  11. Low-energy elastic differential scattering of He/++/ by He.

    NASA Technical Reports Server (NTRS)

    Lam, S. K.; Doverspike, L. D.; Champion, R. L.

    1973-01-01

    Experimental results are developed for the relative elastic differential scattering of He(++) by He for collision energies in the range 4 equal to or less than E equal to or less than 75 eV. In the analysis of the data, semiclassical considerations are utilized, assuming that the dynamics of the scattering is governed solely by the B and E states of He2(++). It is shown that existing ab initio calculations for the intermolecular potentials predict differential cross sections which are not in particularly good agreement with the experimental data.

  12. Target structure independent 7Li elastic scattering at lowmomentum transfers

    SciTech Connect

    Momotyuk, O.A.; Keeley, N.; Kemper, K.W.; Roeder, B.T.; Crisp,A.M.; Cluff, W.; Schmidt, B.G.; Wiedeking, M.; Marechal, F.; Rusek, K.; Mezhevych, S.Yu.; Liendo, J.

    2006-07-20

    Analyzing powers and cross sections for the elastic scattering of polarized 7Li by targets of 6Li, 7Li and 12C are shown to depend only on the properties of the projectile for momentum transfers of less than 1.0 fm-1. The result of a detailed analysis of the experimental data within the framework of the coupled channels model with ground state reorientation and transitions to the excited states of the projectile and targets included in the coupling schemes are presented. This work suggests that nuclear properties of weakly-bound nuclei can be tested by elastic scattering experiments, independent of the target used, if data are acquired for momentum transfers less than {approx}1.0 fm-1.

  13. Measurement of neutrino flux from neutrino-electron elastic scattering

    DOE PAGESBeta

    Park, J.; Aliaga, L.; Altinok, O.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Cai, T.; et al

    2016-06-10

    In muon-neutrino elastic scattering on electrons is an observable neutrino process whose cross section is precisely known. Consequently a measurement of this process in an accelerator-based νμ beam can improve the knowledge of the absolute neutrino flux impinging upon the detector; typically this knowledge is limited to ~10% due to uncertainties in hadron production and focusing. We also isolated a sample of 135±17 neutrino-electron elastic scattering candidates in the segmented scintillator detector of MINERvA, after subtracting backgrounds and correcting for efficiency. We show how this sample can be used to reduce the total uncertainty on the NuMI νμ flux frommore » 9% to 6%. Finally, our measurement provides a flux constraint that is useful to other experiments using the NuMI beam, and this technique is applicable to future neutrino beams operating at multi-GeV energies.« less

  14. Measurement of neutrino flux from neutrino-electron elastic scattering

    NASA Astrophysics Data System (ADS)

    Park, J.; Aliaga, L.; Altinok, O.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Cai, T.; Carneiro, M. F.; Christy, M. E.; Chvojka, J.; da Motta, H.; Dytman, S. A.; Díaz, G. A.; Eberly, B.; Felix, J.; Fields, L.; Fine, R.; Gago, A. M.; Galindo, R.; Ghosh, A.; Golan, T.; Gran, R.; Harris, D. A.; Higuera, A.; Kleykamp, J.; Kordosky, M.; Le, T.; Maher, E.; Manly, S.; Mann, W. A.; Marshall, C. M.; Martinez Caicedo, D. A.; McFarland, K. S.; McGivern, C. L.; McGowan, A. M.; Messerly, B.; Miller, J.; Mislivec, A.; Morfín, J. G.; Mousseau, J.; Naples, D.; Nelson, J. K.; Norrick, A.; Nuruzzaman; Osta, J.; Paolone, V.; Patrick, C. E.; Perdue, G. N.; Rakotondravohitra, L.; Ramirez, M. A.; Ray, H.; Ren, L.; Rimal, D.; Rodrigues, P. A.; Ruterbories, D.; Schellman, H.; Solano Salinas, C. J.; Tagg, N.; Tice, B. G.; Valencia, E.; Walton, T.; Wolcott, J.; Wospakrik, M.; Zavala, G.; Zhang, D.; Miner ν A Collaboration

    2016-06-01

    Muon-neutrino elastic scattering on electrons is an observable neutrino process whose cross section is precisely known. Consequently a measurement of this process in an accelerator-based νμ beam can improve the knowledge of the absolute neutrino flux impinging upon the detector; typically this knowledge is limited to ˜10 % due to uncertainties in hadron production and focusing. We have isolated a sample of 135 ±17 neutrino-electron elastic scattering candidates in the segmented scintillator detector of MINERvA, after subtracting backgrounds and correcting for efficiency. We show how this sample can be used to reduce the total uncertainty on the NuMI νμ flux from 9% to 6%. Our measurement provides a flux constraint that is useful to other experiments using the NuMI beam, and this technique is applicable to future neutrino beams operating at multi-GeV energies.

  15. Elasticity of biomembranes studied by dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Fujime, Satoru; Miyamoto, Shigeaki

    1991-05-01

    Combination of osmotic swelling and dynamic light scattering makes it possible to measure the elastic modulus of biomembranes. By this technique we have observed a drastic increase in membrane flexibility on activation of Na/glucose cotransporters in membrane vesicles prepared from brush-borders of rat small intestine and on activation by micromolar [Ca2] of exocytosis in secretory granules isolated from rat pancreatic acinar cells and bovine adrenal chromaffin cells. 1 .

  16. Visualization of scattering strength of elastic bodies in a fluid

    NASA Astrophysics Data System (ADS)

    Schenck, H. A.; Fales, J. L.

    1992-07-01

    As Part of the Submarine Technology Program, the Defense Advanced Research Projects Agency (DARPA) recently sponsored a Low-Frequency Structural Acoustics Benchmark Exercise. The purpose of the exercise was to test and validate several major computational codes that have been developed to solve acoustic scattering problems of elastic objects in a fluid. This report describes some of the visualization techniques and procedures that were developed to review, compare, and analyze the large amount of computational data generated in the exercise.

  17. Practical correction procedures for elastic electron scattering effects in ARXPS

    NASA Astrophysics Data System (ADS)

    Lassen, T. S.; Tougaard, S.; Jablonski, A.

    2001-06-01

    Angle-resolved XPS and AES (ARXPS and ARAES) are widely used for determination of the in-depth distribution of elements in the surface region of solids. It is well known that elastic electron scattering has a significant effect on the intensity as a function of emission angle and that this has a great influence on the determined overlayer thicknesses by this method. However the applied procedures for ARXPS and ARAES generally neglect this because no simple and practical procedure for correction has been available. However recently, new algorithms have been suggested. In this paper, we have studied the efficiency of these algorithms to correct for elastic scattering effects in the interpretation of ARXPS and ARAES. This is done by first calculating electron distributions by Monte Carlo simulations for well-defined overlayer/substrate systems and then to apply the different algorithms. We have found that an analytical formula based on a solution of the Boltzmann transport equation provides a good account for elastic scattering effects. However this procedure is computationally very slow and the underlying algorithm is complicated. Another much simpler algorithm, proposed by Nefedov and coworkers, was also tested. Three different ways of handling the scattering parameters within this model were tested and it was found that this algorithm also gives a good description for elastic scattering effects provided that it is slightly modified so that it takes into account the differences in the transport properties of the substrate and the overlayer. This procedure is fairly simple and is described in detail. The model gives a much more accurate description compared to the traditional straight-line approximation (SLA). However it is also found that when attenuation lengths instead of inelastic mean free paths are used in the simple SLA formalism, the effects of elastic scattering are also reasonably well accounted for. Specifically, from a systematic study of several

  18. Experiment to measure total cross sections, differential cross sections and polarization effects in pp elastic scattering at RHIC

    SciTech Connect

    Guryn, W.

    1998-02-01

    The authors are describing an experiment to study proton-proton (pp) elastic scattering experiment at the Relativistic Heavy Ion Collider (RHIC). Using both polarized and unpolarized beams, the experiment will study pp elastic scattering from {radical}s = 50 GeV to {radical}s = 500 GeV in two kinematical regions. In the Coulomb Nuclear Interference (CNI) region, 0.0005 < {vert_bar}t{vert_bar} < 0.12 (GeV/c){sup 2}, they will measure and study the s dependence of the total and elastic cross sections, {sigma}{sub tot} and {sigma}{sub el}; the ratio of the real to the imaginary part of the forward elastic scattering amplitude, {rho}; and the nuclear slope parameter of the pp elastic scattering, b. In the medium {vert_bar}t{vert_bar}-region, {vert_bar}t{vert_bar} < 1.5 (GeV/c){sup 2}, they plan to study the evolution of the dip structure with s, as observed at ISR in the differential elastic cross section, d{sigma}{sub el}/dt, and the s and {vert_bar}t{vert_bar} dependence of b. With the polarized beams the following can be measured: the difference in the total cross sections as function of initial transverse spin states {Delta}{sigma}{sub T}, the analyzing power, A{sub N}, and the transverse spin correlation parameter A{sub NN}. The behavior of the analyzing power A{sub N} at RHIC energies in the dip region of d{sigma}{sub el}/dt, where a pronounced structure was found at fixed-target experiments will be studied. The relation of pp elastic scattering to the beam polarization measurement at RHIC is also discussed.

  19. N13+p elastic resonance scattering via a thick-target method

    NASA Astrophysics Data System (ADS)

    Wang, Y. B.; Wang, B. X.; Qin, X.; Bai, X. X.; Guo, B.; Jiang, C.; Li, Y. J.; Li, Z. H.; Lian, G.; Su, J.; Zeng, S.; Liu, W. P.

    2008-04-01

    The N13+p elastic resonance scattering has been studied in inverse kinematics via a thick-target method. A N13 secondary beam of 47.8±1.5 MeV produced by the H2(C12,N13)n reaction was used to bombard a 9.33 mg/cm2 (CH2)n target. The recoil protons were detected by a ΔE-E silicon counter telescope at θlab=15°. The performance of the setup was checked by C12+p elastic resonance scattering with the same (CH2)n target. The excitation function for the N13(p,p) elastic scattering was obtained in the energy interval of Ec.m.~0.5-3.2 MeV and was analyzed by using a multilevel R-matrix code MULTI7. Several low-lying excited states in O14 were surveyed. Our results confirm a very recent 2- assignment to the 6.8 MeV level and agree with the observation of a new 0- level at 5.7 MeV with a width of 400(45) keV.

  20. Deconstruction and elastic ππ scattering in Higgsless models

    NASA Astrophysics Data System (ADS)

    Chivukula, R. Sekhar; Simmons, Elizabeth H.; He, Hong-Jian; Kurachi, Masafumi; Tanabashi, Masaharu

    2007-02-01

    We study elastic pion-pion scattering in global linear moose models and apply the results to a variety of Higgsless models in flat and anti-de Sitter (AdS) space using the equivalence theorem. In order to connect the global moose to Higgsless models, we first introduce a block-spin transformation which corresponds, in the continuum, to the freedom to perform coordinate transformations in the Higgsless model. We show that it is possible to make an “f-flat” deconstruction in which all of the f-constants fj of the linear moose model are identical; the phenomenologically relevant f-flat models are those in which the coupling constants of the groups at either end of the moose are small—corresponding to the global linear moose. In studying pion-pion scattering, we derive various sum rules, including one analogous to the Kawarabayashi-Suzuki-Riazuddin-Fayyazuddin (KSRF) relation, and use them in evaluating the low-energy and high-energy forms of the leading elastic partial-wave scattering amplitudes. We obtain elastic unitarity bounds as a function of the mass of the lightest KK mode and discuss their physical significance.

  1. Deconstruction and elastic {pi}{pi} scattering in Higgsless models

    SciTech Connect

    Chivukula, R. Sekhar; Simmons, Elizabeth H.; He, Hong-Jian; Kurachi, Masafumi; Tanabashi, Masaharu

    2007-02-01

    We study elastic pion-pion scattering in global linear moose models and apply the results to a variety of Higgsless models in flat and anti-de Sitter (AdS) space using the equivalence theorem. In order to connect the global moose to Higgsless models, we first introduce a block-spin transformation which corresponds, in the continuum, to the freedom to perform coordinate transformations in the Higgsless model. We show that it is possible to make an 'f-flat' deconstruction in which all of the f-constants f{sub j} of the linear moose model are identical; the phenomenologically relevant f-flat models are those in which the coupling constants of the groups at either end of the moose are small--corresponding to the global linear moose. In studying pion-pion scattering, we derive various sum rules, including one analogous to the Kawarabayashi-Suzuki-Riazuddin-Fayyazuddin (KSRF) relation, and use them in evaluating the low-energy and high-energy forms of the leading elastic partial-wave scattering amplitudes. We obtain elastic unitarity bounds as a function of the mass of the lightest KK mode and discuss their physical significance.

  2. Elastic waves in discontinuous media: Three-dimensional scattering

    NASA Astrophysics Data System (ADS)

    Molino, F. R.; Sabatier, P. C.

    1994-09-01

    This report contains an exact study of elastic wave propagation and its scattering in discontinuous media where hard reflectors are onionlike sets of surfaces. In order to reformulate the problem as a finite set of boundary integral equations, the wave motion between reflectors is represented by means of elastic potentials which involve vectorial densities on the surfaces. In the external medium, an outgoing asymptotic condition generalizes the Silver-Müller (and the Sommerfeld) condition to the case of coupled waves (S and P waves) moving with different velocities. The uniqueness of the Green's function, which guarantees the uniqueness of the direct problem solution, is proven. For any incident wave and arbitrary number of surfaces, the transmission and scattering problems are studied, with and without the simplification obtained by assuming constant Poisson ratios. According to the parameter ranges, the equations which are obtained are well posed, either as second kind Fredholm equations, or because they reduce to the inverse of the sum of the identity operator and a ``small norm'' bounded operator. The results can be used to describe rigorously the three-dimensional scattering of elastic waves in the frequency domain for any kind of incident wave function (P,S,...) as well as the response to a localized source.

  3. Shallow Lunar Hydrogen and Forward-Scattered Albedo Protons

    NASA Astrophysics Data System (ADS)

    Wilson, J. K.; Schwadron, N.; Jordan, A. P.; Spence, H. E.; Looper, M. D.; Townsend, L. W.

    2015-11-01

    The CRaTER instrument sees a ~40% higher flux of lunar albedo protons (>65 MeV) at grazing angles compared to the nadir direction. A shallow layer (<10 cm) of hydrated lunar regolith may enhance the yield of forward-scattered albedo protons.

  4. Angularly-resolved elastic light scattering of micro-particles

    NASA Astrophysics Data System (ADS)

    Aptowicz, Kevin B.

    From microbiology to astrophysics, the scientific community has long embraced elastic light scattering from small particles as a diagnostic tool. Elastic light scattering has an extremely large scattering cross-section, allowing for single particle interrogation. This is critical in applications where trace amounts of suspect particles are to be detected in a diverse background of natural aerosols. By angularly-resolving the elastically scattered light, features can be detected in these patterns that are sensitive to a particle's morphology (shape, size, internal structure, and composition). An apparatus to collect LA TAOS (Large-Angle Two-dimensional Angular Optical Scattering) patterns from single particles in-situ and in real-time was designed and constructed. The setup utilizes a cross-beam trigger system to minimize the effects of the aberration coma stemming from the main collection optic, an ellipsoidal mirror. LA TAOS patterns of ambient aerosols were collected and analyzed. Approximately 15% of the ambient aerosol had a sphere-like shape. The refractive index of these spheres was estimated by curve-fitting to Lorenz-Mie theory. In addition, the island features prevalent in the LA TAOS pattern were analyzed. Metrics generated from these were used to get partial discrimination between clusters of Bacillus subtilis spores (a simulant for anthrax) and aerosol particles found in the ambient atmosphere. A novel experimental setup for collecting simultaneously LA TAOS patterns at two wavelengths in the mid-infrared was also implemented. With this setup, the relative strength of single-particle absorption could be discerned at the two illuminating wavelengths.

  5. Elastic Properties of Lithium Germanate Glasses Studied by Brillouin Scattering

    NASA Astrophysics Data System (ADS)

    Kaneda, Kazuhiro; Matsuda, Yu; Kojima, Seiji

    2010-07-01

    To investigate the correlation between structural changes and physical properties, the elastic properties of lithium germanate glasses, xLi2O·(100-x)GeO2 represented as a function of Li2O mole fraction, have been studied in the composition range 6≤x≤36 mol % by Brillouin scattering spectroscopy. Raman spectra have also been measured to clarify the composition variation of structural changes. Several elastic properties, such as sound velocity and elastic modulus, have been determined from the Brillouin shift. The longitudinal and transverse sound velocities increase up to about x=20 mol %, and above x=20 mol %, they become nearly constant. Elastic moduli, such as longitudinal modulus (L) and shear modulus (G), increase gradually up to x=22 mol % and then decrease with a further increase in Li2O content. It is considered that such behaviors are due to the change in the coordination number of germanium atoms and the formation of nonbridging oxygen. Differently from other elastic moduli, Poisson's ratio (σ) shows a similar behavior to sound velocity.

  6. Acoustic and elastic multiple scattering and radiation from cylindrical structures

    NASA Astrophysics Data System (ADS)

    Amirkulova, Feruza Abdukadirovna

    Multiple scattering (MS) and radiation of waves by a system of scatterers is of great theoretical and practical importance and is required in a wide variety of physical contexts such as the implementation of "invisibility" cloaks, the effective parameter characterization, and the fabrication of dynamically tunable structures, etc. The dissertation develops fast, rapidly convergent iterative techniques to expedite the solution of MS problems. The formulation of MS problems reduces to a system of linear algebraic equations using Graf's theorem and separation of variables. The iterative techniques are developed using Neumann expansion and Block Toeplitz structure of the linear system; they are very general, and suitable for parallel computations and a large number of MS problems, i.e. acoustic, elastic, electromagnetic, etc., and used for the first time to solve MS problems. The theory is implemented in Matlab and FORTRAN, and the theoretical predictions are compared to computations obtained by COMSOL. To formulate the MS problem, the transition matrix is obtained by analyzing an acoustic and an elastic single scattering of incident waves by elastic isotropic and anisotropic solids. The mathematical model of wave scattering from multilayered cylindrical and spherical structures is developed by means of an exact solution of dynamic 3D elasticity theory. The recursive impedance matrix algorithm is derived for radially heterogeneous anisotropic solids. An explicit method for finding the impedance in piecewise uniform, transverse-isotropic material is proposed; the solution is compared to elasticity theory solutions involving Buchwald potentials. Furthermore, active exterior cloaking devices are modeled for acoustic and elastic media using multipole sources. A cloaking device can render an object invisible to some incident waves as seen by some external observer. The active cloak is generated by a discrete set of multipole sources that destructively interfere with an

  7. Measuring the 2-gamma Exchange Effect in Electron-Proton Scattering at CLAS

    SciTech Connect

    Bennett, Robert

    2011-10-01

    Recent results from experiments at Jefferson Laboratory, Newport News VA, which measure the ratio of the electric to magnetic form factors of the proton, G{sub E}/G{sub M}, have forced us to reexamine the single photon exchange approximation in lepton-proton elastic scattering. Discrepancies between the ratio obtained via the time-tested Rosenbluth separation method and new polarization transfer measurements, which differ by as much as a factor of three, may be resolved by considering the effect of two photon exchange (TPE). Theoretical corrections for the TPE effect are difficult due to the large number of excited nucleon states that can contribute to the process. The TPE effect can, however, be determined directly by measuring the ratio of the positron-proton to electron-proton elastic scattering cross sections, R = {sigma}(e{sup +})/{sigma}(e{sup -}), since the TPE effect changes sign with the charge of the incident particle. The CLAS TPE experiment at Jefferson Laboratory, will determine the effect of two-photon exchange in elastic lepton-proton scattering by precisely measuring the ratio of positron-proton to electron-proton elastic cross sections over a large kinematic range (0.1 < {var_epsilon} < 0.96, 0.02 {le} Q{sup 2} {le} 2.0). We will accomplish this by directing the 5.5 GeV primary electron beam, provided by the Continuous Electron Beam Accelerator Facility (CEBAF), onto a set of radiators and converters to produce simultaneous and identical beams of electron and positrons. Acceptance and efficiency concerns are minimized by only considering the ratios of the elastic cross sections and switching polarity of magnets in the beam line and the spectrometer. Guided by the results of a short 2006 test run and extensive GEANT based modeling, new shielding and beam line components were designed to maximize luminosity. The unique experimental design and challenges of the TPE experiment and the projected luminosities will be presented.

  8. {Delta} resonance contribution to two-photon exchange in electron-proton scattering

    SciTech Connect

    S. Kondratyuk; P. G. Blunden; W. Melnitchouk; J. A. Tjon

    2005-06-01

    We calculate the effects on the elastic electron-proton scattering cross section of the two-photon exchange contribution with an intermediate {Delta} resonance. The {Delta} two-photon exchange contribution is found to be smaller in magnitude than the previously evaluated nucleon contribution, with an opposite sign at backward scattering angles. The sum of the nucleon and {Delta} two-photon exchange corrections has the angular dependence compatible with both the polarization transfer and the Rosenbluth methods of measuring the nucleon electromagnetic form factors.

  9. Effect of repulsive and attractive three-body forces on nucleus-nucleus elastic scattering

    SciTech Connect

    Furumoto, T.; Sakuragi, Y.; Yamamoto, Y.

    2009-10-15

    The effect of the three-body force (TBF) is studied in nucleus-nucleus elastic scattering on the basis of Brueckner theory for nucleon-nucleon (NN) effective interaction (complex G matrix) in the nuclear matter. A new G matrix called CEG07 proposed recently by the present authors includes the TBF effect and reproduces a realistic saturation curve in the nuclear matter, and it is shown to well reproduce proton-nucleus elastic scattering. The microscopic optical potential for the nucleus-nucleus system is obtained by folding the G matrix with nucleon density distributions in colliding nuclei. We first analyze in detail the {sup 16}O+{sup 16}O elastic scattering at E/A=70 MeV. The observed cross sections are nicely reproduced up to the most backward scattering angles only when the TBF effect is included. The use of the frozen-density approximation (FDA) is essentially important to properly estimate the effect of the TBF in nucleus-nucleus scattering. Other prescriptions for defining the local density have also been tested, but only the FDA prescription gives a proper description of the experimental cross sections as well as the effect of the TBF. The effects of the three-body attraction and the {omega}-rearrangement term are also analyzed. The CEG07 interaction is compared with CDM3Y6, which is a reliable and successful effective density-dependent NN interaction used in the double-folding model. The CEG07 G matrix is also tested in the elastic scattering of {sup 16}O by the {sup 12}C, {sup 28}Si, and {sup 40}Ca targets at E/A=93.9 MeV, and in the elastic scattering of {sup 12}C by the {sup 12}C target at E/A=135 MeV with great success. The decisive effect of the TBF is clearly seen also in those systems. Finally, we have tested CEG07a, CEG07b, and CEG07c for the {sup 16}O+{sup 16}O system at various energies.

  10. Elastic scattering measurements for {sup 7}Be+{sup 27}Al system at RIBRAS facility

    SciTech Connect

    Morcelle, V.; Lichtenthaeler, R.; Morais, M. C.; Lepine-Szily, A.; Guimaraes, V.; Faria, P. N. de; Gasques, L.; Pires, K. C. C.; Condori, R. P.; Gomes, P. R. S.; Lubian, J.; Mendes, D. R. Jr.; Barioni, A.; Shorto, J. M. B.; Zamora, J. C.

    2013-05-06

    Elastic scattering angular distribution measurements of {sup 7}Be+{sup 27}Al system were performed at the laboratory energy of 15.6 MeV. The {sup 7}Be secondary beam was produced by the proton transfer reaction {sup 3}He({sup 6}Li,{sup 7}Be) and impinged on {sup 27}Al and {sup 197}Au targets, using the Radioactive Ion Beam (RIB) facility, RIBRAS. The elastic angular distribution was obtained within the angular range of 15{sup 0} - 80{sup 0} at the center of mass frame. Optical model calculations have been performed using the Woods- Saxon form factors and the Sao Paulo potential to fit the experimental data. The total reaction cross section was derived.

  11. Elastic wave scattering to characterize heterogeneities in the borehole environment

    NASA Astrophysics Data System (ADS)

    Tang, Xiao-Ming; Li, Zhen; Hei, Chuang; Su, Yuan-Da

    2016-04-01

    Scattering due to small-scale heterogeneities in the rock formation surrounding a wellbore can significantly change the acoustic waveform from a logging measurement which in turn can be used to characterize the formation heterogeneities. This study simulates the elastic heterogeneity scattering in monopole and dipole acoustic logging and analyse the resulting effects on the waveforms. The results show that significant coda waves are generated in both monopole and dipole waveforms and the dipole coda is dominated by S-to-S scattering, which can be effectively utilized to diagnose the heterogeneity in the rock formation. The coda wave modelling and analysis were used to characterize dipole acoustic data logged before and after fracturing a reservoir interval, with significant coda wave in the after-fracturing data indicating fracturing-induced heterogeneous property change in the rock volume surrounding the borehole.

  12. Consistency of electron scattering data with a small proton radius

    NASA Astrophysics Data System (ADS)

    Griffioen, Keith; Carlson, Carl; Maddox, Sarah

    2016-06-01

    We determine the charge radius of the proton by analyzing the published low momentum transfer electron-proton scattering data from Mainz. We note that polynomial expansions of the form factor converge for momentum transfers squared below 4 mπ2 , where mπ is the pion mass. Expansions with enough terms to fit the data, but few enough not to overfit, yield proton radii smaller than the CODATA or Mainz values and in accord with the muonic atom results. We also comment on analyses using a wider range of data, and overall obtain a proton radius RE=0.840 (16 ) fm.

  13. Proton-proton Scattering Above 3 GeV/c

    SciTech Connect

    A. Sibirtsev, J. Haidenbauer, H.-W. Hammer S. Krewald ,Ulf-G. Meissner

    2010-01-01

    A large set of data on proton-proton differential cross sections, analyzing powers and the double-polarization parameter A{sub NN} is analyzed employing the Regge formalism. We find that the data available at proton beam momenta from 3 GeV/c to 50 GeV/c exhibit features that are very well in line with the general characteristics of Regge phenomenology and can be described with a model that includes the {rho}, {omega}, f{sub 2}, and a{sub 2} trajectories and single-Pomeron exchange. Additional data, specifically for spin-dependent observables at forward angles, would be very helpful for testing and refining our Regge model.

  14. A Microscopic Optical Potential Approach to {sup 6,8}He+p Elastic Scattering

    SciTech Connect

    Lukyanov, V. K.; Zemlyanaya, E. V.; Lukyanov, K. V.; Kadrev, D. N.; Antonov, A. N.; Gaidarov, M. K.; Massen, S. E.

    2009-08-26

    A microscopic approach to calculate the optical potential (OP) with the real part obtained by a folding procedure and with the imaginary part inherent in the high-energy approximation (HEA) is applied to study the {sup 6,8}He+p elastic scattering data at energies of tens of MeV/N. The OP's and the cross sections are calculated using different models for the neutron and proton densities of {sup 6,8}He. The role of the spin-orbit (SO) potential and effects of the energy and density dependence of the effective NN forces are studied. Comparison of the calculations with the available experimental data on the elastic scattering differential cross sections at beam energies <100 MeV/N is performed and conclusions on the role of the aforesaid effects are made. It is shown that the present approach, which uses only parameters that renormalize the depths of the OP, can be applied along with other methods like that from the microscopic g-matrix description of the complex proton optical potential.

  15. Studies of toxic aerosols via elastic and inelastic light scattering

    SciTech Connect

    Foss, W.; Li, W.; Allen, T.M.; Blair, D.S.; Davis, E.J. )

    1993-02-01

    Evaporation rates and chemical characteristics of potentially toxic aerosols have been determined by elastic and inelastic light-scattering measurements. The aerosol systems examined were a commercial catalyst consisting of a mixture of stannous octanoate (SNO) and 2-ethylhexanoic acid (EHA) and droplets emitted from open tanks of chromic acid solutions used for anodizing aluminum. The heavy metals contained in these aerosols represent a danger to the workplace if such materials are inhaled. Nanogram amounts of the solutions were studied by suspending single microdroplets in electrodynamic balances in a flow of air to measure evaporation rates and to obtain Raman spectra. Elastic scattering data include phase functions and morphological resonance spectra from which droplet sizes are determined. The inelastic light-scattering data or Raman spectra provide molecular vibrational bond information. It was found that EHA spectra agree with bulk data in the literature, and that SNO Raman spectra, which are not available in the literature, are consistent with infrared spectra for bulk SNO. At room temperature the vapor pressure of SNO is on the order of 0.01 Pa while that of EHA is on the order of 0.1 Pa. Raman data for the residue of evaporated chromic acid solutions show the presence of chromium oxides (Cr[sup 6+] compounds), surfactants, and bound (nonvolatile) water. 31 refs., 14 figs.

  16. Elastic and Inelastic Scattering of Neutrons using a CLYC array

    NASA Astrophysics Data System (ADS)

    Brown, Tristan; Doucet, E.; Chowdhury, P.; Lister, C. J.; Wilson, G. L.; Devlin, M.; Mosby, S.

    2015-10-01

    CLYC scintillators, which have dual neutron and gamma response, have recently ushered in the possibility of fast neutron spectroscopy without time-of-flight (TOF). A 16-element array of 1'' x 1'' 6Li-depleted CLYC crystals, where pulse-shape-discrimination is achieved via digital pulse processing, has been commissioned at UMass Lowell. In an experiment at LANSCE, high energy neutrons were used to bombard 56Fe and 238U targets, in order to measure elastic and inelastic neutron scattering cross sections as a function of energy and angle with the array. The array is placed very close to the targets for enhanced geometrical solid angles for scattered neutrons compared to standard neutron-TOF measurements. A pulse-height spectrum of scattered neutrons in the detectors is compared to the energy of the incident neutrons, which is measured via the TOF of the pulsed neutrons from the source to the detectors. Recoil corrections are necessary to combine the energy spectra from all the detectors to obtain angle-integrated elastic and inelastic cross-sections. The detection techniques, analysis procedures and results will be presented. Supported by NNSA-SSAA program through DOE Grant DE-NA00013008.

  17. Overview of single-cell elastic light scattering techniques.

    PubMed

    Kinnunen, Matti; Karmenyan, Artashes

    2015-05-01

    We present and discuss several modern optical methods based on elastic light scattering (ELS), along with their technical features and applications in biomedicine and life sciences. In particular, we review some ELS experiments at the single-cell level and explore new directions of applications. Due to recent developments in experimental systems (as shown in the literature), ELS lends itself to useful applications in the life sciences. Of the developed methods, we cover elastic scattering spectroscopy, optical tweezer-assisted measurement, goniometers, Fourier transform light scattering (FTLS), and microscopic methods. FTLS significantly extends the potential analysis of single cells by allowing monitoring of dynamical changes at the single-cell level. The main aim of our review is to demonstrate developments in the experimental investigation of ELS in single cells including issues related to theoretical “representations” and modeling of biological systems (cells, cellular systems, tissues, and so on). Goniometric measurements of ELS from optically trapped single cells are shown and the importance of the experimental verification of theoretical models of ELS in the context of biomedical applications is discussed. PMID:25760756

  18. Elastic scattering of electrons from singly ionized argon

    SciTech Connect

    Griffin, D.C.; Pindzola, M.S.

    1996-03-01

    Recently, Greenwood {ital et} {ital al}. [Phys. Rev. Lett. {bold 75}, 1062 (1995)] reported measurements of large-angle elastic scattering of electrons from singly ionized argon at an energy of 3.3 eV. They compared their results for the differential cross section with cross sections determined using phase shifts obtained from two different scattering potentials and found large discrepancies between theory and experiment at large angles. They state that these differences may be due to the effects of polarization of the target, which are not included in their calculations, as well as inaccurate representations of electron exchange in the local scattering potentials that are employed to determine the phase shifts. In order to test these proposed explanations of the discrepancies, we have carried out calculations of elastic scattering from Ar{sup +} using the {ital R}-matrix method. We compare both a single-state calculation, which does not include polarization, and a 17-state calculation, in which the effects of dipole polarizability are included through the use of polarization pseudostates within the close-coupling expansion, to each other and with the measurements. We find some differences between the two calculations at intermediate scattering angles, but very close agreement at angles above 100{degree}. Although the calculated cross sections agree with experiment between 120{degree} and 135{degree}, large discrepancies persist at angles above 135{degree}. We conclude that the differences between the measurements and theory cannot be explained on the basis of an inaccurate representation of electron exchange or polarization of the target. {copyright} {ital 1996 The American Physical Society.}

  19. A method for calculating proton-nucleus elastic cross-sections

    NASA Technical Reports Server (NTRS)

    Tripathi, R. K.; Wilson, J. W.; Cucinotta, F. A.

    2002-01-01

    Recently [Nucl. Instr. and Meth. B 145 (1998) 277; Extraction of in-medium nucleon-nucleon amplitude from experiment, NASA-TP, 1998], we developed a method of extracting nucleon-nucleon (N-N) cross-sections in the medium directly from experiment. The in-medium N-N cross-sections form the basic ingredients of several heavy-ion scattering approaches including the coupled-channel approach developed at the NASA Langley Research Center. We investigated [Proton-nucleus total cross-sections in coupled-channel approach, NASA/TP, 2000; Nucl. Instr. and Meth. B 173-174 (2001) 391] the ratio of real to imaginary part of the two body scattering amplitude in the medium. These ratios are used in combination with the in-medium N-N cross-sections to calculate proton-nucleus elastic cross-sections. The agreement is excellent with the available experimental data. These cross-sections are needed for the radiation risk assessment of space missions. c2002 Elsevier Science B.V. All rights reserved.

  20. About multiple scattering of high energy protons in crystal deflectors

    NASA Astrophysics Data System (ADS)

    Taratin, A. M.; Scandale, W.

    2015-07-01

    The process of multiple scattering of high energy protons in a silicon crystal at its amorphous orientation was studied by simulation of proton trajectories in the model of binary collisions and by a straight simulation of the sequences of proton collisions with atoms when their impact parameters are randomly and uniformly distributed on the symmetry cell for a given crystallography direction. The value of the RMS deflection of multiple scattering obtained by the simulation is in a good agreement with the experiment and more than 15% larger than it follows from the Moliere theory. The obtained RMS deflection used in the Gaussian approach of multiple scattering well describes dechanneling of protons in the frame of the planar potential model. Different number of proton collisions with atoms occurs along the same crystal length for different crystal orientations. However, the change of the collision number is compensated by the corresponding change of the mean square deflection in a single collision. Therefore, multiple scattering is the same for different crystal orientations. The generator of multiple scattering for amorphous crystal orientations was proposed.

  1. Proton radiography, nuclear cross sections and multiple scattering

    NASA Astrophysics Data System (ADS)

    Sjue, Sky; Lansce Proton Radiography Team

    2015-10-01

    Proton radiography is a valuable tool for assessing dynamic experiments over times as short as 100 nanoseconds. Facilities now exist or are in development in the China, Germany, Russia and the United States with proton energies ranging from 800 MeV to 50 GeV. The multiple Coulomb scattering distribution of protons and the cross sections for proton interactions with the nucleus both depend on the proton energy. A detailed understanding of these effects is necessary to gain the best possible quantitative information from proton generated radiographs. We will present an analysis of the integrated nuclear cross sections for various metals at 800 MeV kinetic energy using step wedges at Los Alamos Neutron Science Center at 800 MeV, along with results at 24 GeV from Alternating Gradient Synchrotron at 24 GeV. The results will be compared with models of multiple scattering and several models of the nuclear interactions. Finally, we will discuss trends in the interplay between nuclear attenuation and multiple scattering as a function of proton energy.

  2. Elastic Scattering of Electron Vortex Beams in Magnetic Matter

    NASA Astrophysics Data System (ADS)

    Edström, Alexander; Lubk, Axel; Rusz, Ján

    2016-03-01

    Elastic scattering of electron vortex beams on magnetic materials leads to a weak magnetic contrast due to Zeeman interaction of orbital angular momentum of the beam with magnetic fields in the sample. The magnetic signal manifests itself as a redistribution of intensity in diffraction patterns due to a change of sign of the orbital angular momentum of the electron vortex beam. While in the atomic resolution regime the magnetic signal is most likely under the detection limits of present transmission electron microscopes, for electron probes with high orbital angular momenta, and correspondingly larger spatial extent, its detection is predicted to be feasible.

  3. Proton beam scattering system optimization for clinical and research applications

    SciTech Connect

    Wroe, A. J.; Schulte, R. W.; Slater, J. D.; Barnes, S.; McAuley, G.; Slater, J. M.

    2013-04-15

    Purpose: To develop and test a method for optimizing and constructing a dual scattering system in passively scattered proton therapy. Methods: A beam optics optimization algorithm was developed to optimize the thickness of the first scatterer (S1) and the profile (of both the high-Z material and Lexan) of the second scatterer (S2) to deliver a proton beam matching a given set of parameters, including field diameter, fluence, flatness, and symmetry. A new manufacturing process was also tested that allows the contoured second scattering foil to be created much more economically and quickly using Cerrobend casting. Two application-specific scattering systems were developed and tested using both experimental and Monte Carlo techniques to validate the optimization process described. Results: A scattering system was optimized and constructed to deliver large uniform irradiations of radiobiology samples at low dose rates. This system was successfully built and tested using film and ionization chambers. The system delivered a uniform radiation field of 50 cm diameter (to a dose of {+-}7% of the central axis) while the depth dose profile could be tuned to match the specifications of the particular investigator using modulator wheels and range shifters. A second scattering system for intermediate field size (4 cm < diameter < 10 cm) stereotactic radiosurgery and radiation therapy (SRS and SRT) treatments was also developed and tested using GEANT4. This system improved beam efficiency by over 70% compared with existing scattering systems while maintaining field flatness and depth dose profile. In both cases the proton range uniformity across the radiation field was maintained, further indicating the accuracy of the energy loss formalism in the optimization algorithm. Conclusions: The methods described allow for rapid prototyping of scattering foils to meet the demands of both research and clinical beam delivery applications in proton therapy.

  4. cap alpha. /sup 4/He elastic scattering at high energies

    SciTech Connect

    Usmani, A.A.; Ahmad, I.; Usmani, Q.N.

    1989-03-01

    Differential cross sections for ..cap alpha.. /sup 4/He elastic scattering have been calculated at incident ..cap alpha..-particle momenta of 4.32, 5.07, and 7.0 GeV/c within the framework of Glauber multiple scattering theory. The full Glauber amplitude has been calculated using the Monte Carlo method for evaluating multidimensional integrals. We found that, in general, the more realistic double-Gaussian model for the density brings theory closer to experiment as compared to the generally used single-Gaussian model in some momentum transfer regions. Our results with the double-Gaussian model and an acceptable set of NN parameters are in fairly good agreement with the experimental data at 4.32 and 5.07 GeV/c.

  5. Elastic scattering of low-energy electrons from toluene

    NASA Astrophysics Data System (ADS)

    Sakaamini, Ahmad; Hargreaves, L. R.; Khakoo, M. A.; Pastega, D. F.; Bettega, M. H. F.

    2016-04-01

    Theoretical and normalized experimental differential, momentum transfer, and integral cross sections for vibrationally elastic scattering of low-energy electrons from toluene (C6H5C H3 ) are presented. The differential cross sections are measured at incident energies from 1 to 20 eV and scattering angles from 15° to 130°. The calculated cross sections are obtained using the Schwinger multichannel method with pseudopotentials in the static-exchange plus polarization approximation. Comparisons are made between the present theory and measurements with earlier available measurements. In general, the agreement between the theory and the experiment is very good. We also discuss the resonance spectra of toluene, where we find three π* shape resonances whose locations agree well with the experiment. In addition, we compare the cross sections of toluene and benzene, since the former can be considered as a benzene derivative by the substitution of a hydrogen in benzene by a C H3 group in toluene.

  6. Elastic scattering of Beryllium isotopes near the Coulomb barrier

    SciTech Connect

    Di Pietro, A.; Figuera, P.; Amorini, F.; Fisichella, M.; Lattuada, M.; Musumarra, A.; Pellegriti, M. G.; Randisi, G.; Rizzo, F.; Santonocito, D.; Scalia, G.; Scuderi, V.; Strano, E.; Torresi, D.; Papa, M.; Acosta, L.; Martel, I.; Perez-Bernal, F.; Borge, M. J. G.; Tengblad, O.

    2011-10-28

    In this contribution, results of experiments performed with the three Beryllium isotopes {sup 9,10,11}Be on a medium mass {sup 64}Zn target, at a center of mass energy of {approx_equal}1.4 the Coulomb barrier, will be discussed. Elastic scattering angular distributions have been measured for the {sup 9,10}Be reactions. In the {sup 11}Be case the quasielastic scattering angular distribution was obtained. In the halo nucleus case, the angular distribution exhibit a non-Fresnel-type pattern with a strong damping of the Coulomb-nuclear interference peak. Moreover, it is found that the total reaction cross-section for the halo nucleus induced collision is more than double the ones extracted in the collisions induced by the non-halo Beryllium isotopes. A large contribution to the total-reaction cross-section in the {sup 11}Be case could be attributed to transfer and/or break-up events.

  7. High Precision Measurement of the Proton Elastic Form Factor Ratio at Low Q2

    SciTech Connect

    Zhan, Xiaohui

    2010-01-01

    Experiment E08-007 measured the proton elastic form factor ratio μpGE/GM in the range of Q2 = 0.3-0.7(GeV/c)2 by recoil polarimetry. Data were taken in 2008 at the Thomas Jefferson National Accelerator Facility in Virginia, USA. A 1.2 GeV polarized electron beam was scattered off a cryogenic hydrogen target. The recoil proton was detected in the left HRS in coincidence with the elasticly scattered electrons tagged by the BigBite spectrometer. The proton polarization was measured by the focal plane polarimeter (FPP). In this low Q2 region, previous measurement from Jefferson Lab Hall A (LEDEX) along with various fits and calculations indicate substantial deviations of the ratio from unity. For this new measurement, the proposed statistical uncertainty (< 1%) was achieved. These new results are a few percent lower than expected from previous world data and fits, which indicate a smaller GEp at this region. Beyond the intrinsic interest in nucleon structure, the new results also have implications in determining the proton Zemach radius and the strangeness form factors from parity violation experiments.

  8. Inclusive proton spectra and total reaction cross sections for proton-nucleus scattering at 800 MeV

    SciTech Connect

    McGill, J.A.

    1981-08-01

    Current applications of multiple scattering theory to describe the elastic scattering of medium energy protons from nuclei have been shown to be quite successful in reproducing the experimental cross sections. These calculations use the impulse approximation, wherein the scattering from individual nucleons in the nucleus is described by the scattering amplitude for a free nucleon. Such an approximation restricts the inelastic channels to those initiated by nucleon-nucleon scattering. As a first step in determining the nature of p + nucleus scattering at 800 MeV, both total reaction cross sections and (p,p') inclusive cross sections were measured and compared to the free p + p cross sections for hydrogen, deuterium, calcium 40, carbon 12, and lead 208. It is concluded that as much as 85% of all reactions in a nucleus proceed from interactions with a single nucleon in the nucleus, and that the impulse approximation is a good starting point for a microscopic description of p + nucleus interactions at 800 MeV.

  9. Experiment to measure total cross sections, differential cross sections and polarization effects in pp elastic scattering at RHIC

    SciTech Connect

    Guryn, W.

    1995-12-31

    The author is describing an experiment to study proton-proton (pp) elastic scattering experiment at the Relativistic Heavy Ion Collider (RHIC). Using both polarized and unpolarized beams, the experiment will study pp elastic scattering from {radical}s = 60 GeV to {radical}s = 500 GeV in two kinematical regions .In the Coulomb Nuclear Interference (CNI) region, 0.0005 < {vert_bar}t{vert_bar} < 0.12 (GeV/c){sup 2}, we will measure and study the s dependence of the total and elastic cross sections, {sigma}{sub tot} and {sigma}{sub el}; the ratio of the real to the imaginary part of the forward elastic scattering amplitude, {rho}; and the nuclear slope parameter of the pp elastic scattering, b. In the medium {vert_bar}t{vert_bar}, {vert_bar}t{vert_bar} {le} 1.5 (GeV/c){sup 2}, we plan to study the evolution of the dip structure with s, as observed at ISR in the differential elastic cross section, d{sigma}{sub el}/dt, and the s and {vert_bar}t{vert_bar} dependence of b. With the polarized beams the following can be measured: the difference in the total cross sections as function of initial transverse spin stated {Delta}{sigma}{sub T}, the analyzing power, A{sub N}, and the transverse spin correlation parameter A{sub NN}. The behavior of the analyzing power A{sub N} at RHIC energies in the dip region of d{sigma}{sub el}/dt, where a pronounced structure was found at fixed-target experiments will be studied.

  10. Radiative corrections to the elastic e-p and mu-p scattering in Monte Carlo simulation approach

    NASA Astrophysics Data System (ADS)

    Koshchii, Oleksandr; Afanasev, Andrei; MUSE Collaboration

    2015-04-01

    In this paper, we calculated exactly lepton mass corrections for the elastic e-p and mu-p scatterings using the ELRADGEN 2.1 Monte Carlo generator. These estimations are essential to be used in the MUSE experiment that is designed to solve the proton radius puzzle. This puzzle is due to the fact that two methods of measuring proton radius (the spectroscopy method, which measures proton energy levels in hydrogen, and the electron scattering experiment) predicted the radius to be 0.8768 +/-0.0069 fm, whereas the experiment that used muonic hydrogen provided the value that is 5% smaller. Since the radiative corrections are different for electrons and muons due to their mass difference, these corrections are extremely important for analysis and interpretation of upcoming MUSE data.