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Your search keyword '"Rohe, D."' showing total 9 results
Start Over Author "Rohe, D." Publisher american physical society
9 results on '"Rohe, D."'

1. Measurement of the recoil polarization in the p(e, e'p)π0 reaction at the Δ(1232) resonance

Author

Pospischil, T.H., Bartsch, P., Baumann, D., Bermuth, J., Bohm, R., Bohinc, K., Derber, S., Ding, M., Distler, M., Drechsel, D., Elsner, D., Ewald, I., Friedrich, J., Friedrich, J.M., Geiges, R., Hedicke, S., Jennewein, P., Kahrau, M., Kamalov, S.S., Klein, F., Krygier, K.W., Lac, J., Liesenfeld, A., McIntyre, J., Merkel, H., Merle, P., Muller, U., Neuhausen, R., Potokar, M., Ransome, R.D., Rohe, D., Rosner, G., Schmieden, H., Seimetz, M., Sirca, S., Sick, I., Sule, A., Tiator, L., Wagner, A., Walcher, T., Warren, G.A., and Weis, M.

Subjects
QC
Abstract

The recoil proton polarization in the reaction P(e, elp)φ0 at the energy of the [Triangle Open] (1232) resonance was measured. Because of the spin precession in the magnetic spectrometer all three polarization components Px, Py, and Pz were simultaneously accessible. From Px the Coulomb quadrupole to magnetic dipole ratio was determined in the framework of the Mainz Unitary Isobar Model as colossal magnetoresistance (CMR)(Q2 = 0.121 GeV) = (-6.4 ± 0.7stat ± 0.8syst)%, which is in good agreement with the result obtained from the polarization ratio Px/Pz.

Published
2001

2. Measurement of nuclear transparency for the A(e,e'pi+) reaction.

Author

Clasie B, Qian X, Arrington J, Asaturyan R, Benmokhtar F, Boeglin W, Bosted P, Bruell A, Christy ME, Chudakov E, Cosyn W, Dalton MM, Daniel A, Day D, Dutta D, El Fassi L, Ent R, Fenker HC, Ferrer J, Fomin N, Gao H, Garrow K, Gaskell D, Gray C, Horn T, Huber GM, Jones MK, Kalantarians N, Keppel CE, Kramer K, Larson A, Li Y, Liang Y, Lung AF, Malace S, Markowitz P, Matsumura A, Meekins DG, Mertens T, Miller GA, Miyoshi T, Mkrtchyan H, Monson R, Navasardyan T, Niculescu G, Niculescu I, Okayasu Y, Opper AK, Perdrisat C, Punjabi V, Rauf AW, Rodriquez VM, Rohe D, Ryckebusch J, Seely J, Segbefia E, Smith GR, Strikman M, Sumihama M, Tadevosyan V, Tang L, Tvaskis V, Villano A, Vulcan WF, Wesselmann FR, Wood SA, Yuan L, and Zheng XC

Abstract

We have measured the nuclear transparency of the A(e,e'pi+) process in 2H, 12C, 27Al, 63Cu, and 197Au targets. These measurements were performed at the Jefferson Laboratory over a four momentum transfer squared range Q2=1.1 to 4.7 (GeV/c)2. The nuclear transparency was extracted as the super-ratio of (sigmaA/sigmaH) from data to a model of pion-electroproduction from nuclei without pi-N final-state interactions. The Q2 and atomic number dependence of the nuclear transparency both show deviations from traditional nuclear physics expectations and are consistent with calculations that include the quantum chromodynamical phenomenon of color transparency.

Published
2007
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3. Proton spin structure in the resonance region.

Author

Wesselmann FR, Slifer K, Tajima S, Aghalaryan A, Ahmidouch A, Asaturyan R, Bloch F, Boeglin W, Bosted P, Carasco C, Carlini R, Cha J, Chen JP, Christy ME, Cole L, Coman L, Crabb D, Danagoulian S, Day D, Dunne J, Elaasar M, Ent R, Fenker H, Frlez E, Gan L, Gaskell D, Gomez J, Hu B, Jones MK, Jourdan J, Keith C, Keppel CE, Khandaker M, Klein A, Kramer L, Liang Y, Lichtenstadt J, Lindgren R, Mack D, McKee P, McNulty D, Meekins D, Mkrtchyan H, Nasseripour R, Niculescu I, Normand K, Norum B, Pocanic D, Prok Y, Raue B, Reinhold J, Roche J, Rohe D, Rondón OA, Savvinov N, Sawatzky B, Seely M, Sick I, Smith C, Smith G, Stepanyan S, Tang L, Testa G, Vulcan W, Wang K, Warren G, Wood S, Yan C, Yuan L, Yun J, Zeier M, and Zhu H

Abstract

We have examined the spin structure of the proton in the region of the nucleon resonances (1.085 GeV

Published
2007
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4. Correlated strength in the nuclear spectral function.

Author

Rohe D, Armstrong CS, Asaturyan R, Baker OK, Bueltmann S, Carasco C, Day D, Ent R, Fenker HC, Garrow K, Gasparian A, Gueye P, Hauger M, Honegger A, Jourdan J, Keppel CE, Kubon G, Lindgren R, Lung A, Mack DJ, Mitchell JH, Mkrtchyan H, Mocelj D, Normand K, Petitjean T, Rondon O, Segbefia E, Sick I, Stepanyan S, Tang L, Tiefenbacher F, Vulcan WF, Warren G, Wood SA, Yuan L, Zeier M, Zhu H, and Zihlmann B

Abstract

We have carried out an (e,e'p) experiment at high momentum transfer and in parallel kinematics to measure the strength of the nuclear spectral function S(k,E) at high nucleon momenta k and large removal energies E. This strength is related to the presence of short-range and tensor correlations, and was known hitherto only indirectly and with considerable uncertainty from the lack of strength in the independent-particle region. This experiment locates by direct measurement the correlated strength predicted by theory.

Published
2004
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5. Measurement of the electric form factor of the neutron at Q2=0.5 and 1.0 GeV2/c2.

Author

Warren G, Wesselmann F, Zhu H, McKee P, Savvinov N, Zeier M, Aghalaryan A, Ahmidouch A, Arenhövel H, Asaturyan R, Ben-Dayan I, Bloch F, Boeglin W, Boillat B, Breuer H, Brower J, Carasco C, Carl M, Carlini R, Cha J, Chant N, Christy E, Cole L, Coman L, Coman M, Crabb D, Danagoulian S, Day D, Duek K, Dunne J, Elaasar M, Ent R, Farrell J, Fatemi R, Fawcett D, Fenker H, Forest T, Garrow K, Gasparian A, Goussev I, Gueye P, Harvey M, Hauger M, Herrera R, Hu B, Jaegle I, Jones M, Jourdan J, Keith C, Kelly J, Keppel C, Khandaker M, Klein A, Klimenko A, Kramer L, Krusche B, Kuhn S, Liang Y, Lichtenstadt J, Lindgren R, Liu J, Lung A, Mack D, Maclachlan G, Markowitz P, McNulty D, Meekins D, Mitchell J, Mkrtchyan H, Nasseripour R, Niculescu I, Normand K, Norum B, Opper A, Piasetzky E, Pierce J, Pitt M, Prok Y, Raue B, Reinhold J, Roche J, Rohe D, Rondon O, Sacker D, Sawatzky B, Seely M, Sick I, Simicevic N, Smith C, Smith G, Steinacher M, Stepanyan S, Stout J, Tadevosyan V, Tajima S, Tang L, Testa G, Trojer R, Vlahovic B, Vulcan B, Wang K, Wells S, Woehrle H, Wood S, Yan C, Yanay Y, Yuan L, Yun J, and Zihlmann B

Abstract

The electric form factor of the neutron was determined from measurements of the d-->(e-->,e'n)p reaction for quasielastic kinematics. Polarized electrons were scattered off a polarized deuterated ammonia (15ND3) target in which the deuteron polarization was perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle detector. We find G(n)(E)=0.0526+/-0.0033(stat)+/-0.0026(sys) and 0.0454+/-0.0054+/-0.0037 at Q(2)=0.5 and 1.0 (GeV/c)(2), respectively.

Published
2004
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6. Soft fermi surfaces and breakdown of Fermi-liquid behavior.

Author

Metzner W, Rohe D, and Andergassen S

Abstract

Electron-electron interactions can induce Fermi surface deformations which break the point-group symmetry of the lattice structure of the system. In the vicinity of such a "Pomeranchuk instability" the Fermi surface is easily deformed by anisotropic perturbations, and exhibits enhanced collective fluctuations. We show that critical Fermi surface fluctuations near a d-wave Pomeranchuk instability in two dimensions lead to large anisotropic decay rates for single-particle excitations, which destroy Fermi-liquid behavior over the whole surface except at the Brillouin zone diagonal.

Published
2003
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7. Measurement of the electric form factor of the neutron through d-->(e-->,e(')n)p at Q2 = 0.5 (GeV/c)(2).

Author

Zhu H, Ahmidouch A, Anklin H, Arenhövel H, Armstrong C, Bernet C, Boeglin W, Breuer H, Brindza P, Brown D, Bültmann S, Carlini R, Chant N, Cowley A, Crabb D, Danagoulian S, Day DB, Eden T, Ent R, Farah Y, Fatemi R, Garrow K, Harris C, Hauger M, Honegger A, Jourdan J, Kaufmann M, Khandaker M, Kubon G, Lichtenstadt J, Lindgren R, Lourie R, Lung A, Mack D, Malik S, Markowitz P, McFarlane K, McKee P, McNulty D, Milanovich G, Mitchell J, Mkrtchyan H, Mühlbauer M, Petitjean T, Prok Y, Rohe D, Rollinde E, Rondon OA, Roos P, Sawafta R, Sick I, Smith C, Southern T, Steinacher M, Stepanyan S, Tadevosyan V, Tieulent R, Tobias A, Vulcan W, Warren G, Wöhrle H, Wood S, Yan C, Zeier M, Zhao J, and Zihlmann B

Abstract

We report the first measurement using a solid polarized target of the neutron electric form factor G(n)(E) via d-->(e-->,e(')n)p. G(n)(E) was determined from the beam-target asymmetry in the scattering of longitudinally polarized electrons from polarized deuterated ammonia ( 15ND3). The measurement was performed in Hall C at Thomas Jefferson National Accelerator Facility in quasifree kinematics with the target polarization perpendicular to the momentum transfer. The electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle segmented detector. We find G(n)(E) = 0.04632+/-0.00616(stat)+/-0.00341(syst) at Q2 = 0.495 (GeV/c)(2).

Published
2001
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8. Measurement of the recoil polarization in the p(e-->, e'p-->)pi(0) reaction at the Delta(1232) resonance.

Author

Pospischil T, Bartsch P, Baumann D, Bermuth J, Böhm R, Bohinc K, Derber S, Ding M, Distler M, Drechsel D, Elsner D, Ewald I, Friedrich J, Friedrich JM, Geiges R, Hedicke S, Jennewein P, Kahrau M, Kamalov SS, Klein F, Krygier KW, Lac J, Liesenfeld A, McIntyre J, Merkel H, Merle P, Müller U, Neuhausen R, Potokar M, Ransome RD, Rohe D, Rosner G, Schmieden H, Seimetz M, Sirca S, Sick I, Süle A, Tiator L, Wagner A, Walcher T, Warren GA, and Weis M

Abstract

The recoil proton polarization has been measured in the p(e-->,e'p-->)pi(0) reaction in parallel kinematics around W = 1232 MeV, Q2 = 0.121 (GeV/c)2, and epsilon = 0.718 using the polarized cw electron beam of the Mainz Microtron. All three proton polarization components, Px/P(e) = (-11.4+/-1.3+/-1.4)%, P(y) = (-43.1+/-1.3+/-2.2)%, and P(z)/P(e) = (56.2+/-1.5+/-2.6)%, could be measured simultaneously. The Coulomb quadrupole to magnetic dipole ratio, CMR = (-6.4+/-0.7(stat)+/-0.8(syst))%, was determined from Px in the framework of the Mainz Unitary Isobar Model. The consistency among the reduced polarizations and the extraction of the ratio of longitudinal-to-transverse response is discussed.

Published
2001
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9. Devil's staircase-type faceting of a cubic lyotropic liquid crystal

Author

Pieranski P, Sotta P, Rohe D, and Imperor-Clerc M

Abstract

The faceting of monocrystals of the lyotropic cubic liquid crystals in equilibrium with a humid atmosphere is observed. Experiments reveal the presence of more than 60 different types of facets on the surface of a spherical crystal of radius R = 1 mm. The devil's staircase type of faceting has been predicted theoretically when the interaction between steps on the crystal surface is repulsive.

Published
2000
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