Spin Observables of Nuclear Probes PDF
Preview Spin Observables of Nuclear Probes
Spin Observables of Nuclear Probes Spin Observables of Nuclear Probes Edited by Charles J. Horowitz, Charles D. Goodman, and George E. Walker Indiana University Bloomington, Indiana Plenum Press • New York and London Library of Congress Cataloging in Publication Data Telluride International Conference on Spin Observables of Nuclear Probes (1988) Spin Observables of nuclear probes I edited by Charles J. Horowitz, Charles D. Goodman, and George E. Walker. p. cm. "Proceedings of the Telluride International Conference on Spin Observables of Nuclear Probes, held March 14-17, 1988, in Telluride, Colorado" - T.p. verso. Bibliography: p. Includes index. ISBN-13: 978-1-4612-8073-6 e-ISBN-13: 978-1-4613-0769-3 DOl: 10.1007/978-1-4613-0769-3 1. Nuclear spin - Congresses. 2. Nuclear structure - Congresses. I. Horowitz, Charles. II. Goodman, Charles. III. Walker, George E. IV. Title. QC793.3.S8T45 1988 88-38971 539.7'23-dcl9 CIP Proceedings of the Telluride International Conference on Spin Observables of Nuclear Probes, held March 14-17, 1988, in Telluride, Colorado © 1988 Plenum Press, New York Softcover reprint of the hardcover I st edition 1988 A Division of Plenum Publishing Corporation 233 Spring Street, New York, N.Y. 10013 All rights reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher PREFACE The proceedings of the "International Conference on Spin Observables of Nuclear Probes" are presented in this volume. This conference was held in Telluride, Colorado, March 14-17, 1988, and was the fourth in the Telluride series of nuclear physics conferences. A continuing theme in the Telluride conference series has been the complementarity of various intermediate-energy projectiles for elucidating the nucleon-nucleon interaction and nuclear structure. Earlier conferences have contributed significantly to an understanding of spin currents in nuclei, in particular the distribution of Gamow-Teller strength using charge-exchange reactions. The previous conference on "Antinucleon and Nucleon Nucleus Interactions" compared nuclear information from tra tional probes to recent results from antinucleon reactions. The 1988 conference on Spin Observables of Nuclear Probes, put special emphasis on spin observables and brought together experts using spin information to probe nuclear structure. Spin observables have provided very detailed information about nuclear structure and reactions. Since the 1985 Telluride conference we have seen data from new focal plane polarimeters at LAMPF, TRIUMF, IUCF and elsewhere. In addition, spin observables provide an important common ground between electron and hadron scattering physics. In the future we look forward to new facilities such as NTOF for polarized neutron measurements at Los Alamos and a vigorous spin program at CEBAF. The first day of the conference dealt with spin observables in both inclusive (morning) and coincidence reactions (afternoon). Charge exchange reactions were discussed on the second day and relativistic descriptions of nuclei on the third day. There has always been a close relationship between relativity and spin. Proton scattering spin obser vables presented at the '85 conference have led to much theoretical work on relativistic models in the intervening years. Finally, spin observables in few body systems were presented on the fourth day. We are very happy that five eastern bloc physicists from Dubna and Novosibirsk were able to attend the conference. We hope that this signals an increase in East/West physics collaborations in the future. We wish to gratefully acknowledge the sponsorship of the National Science Foundation. We are also grateful for the support from Horshaw/ Filtrol, Inc. in sponsoring the reception for the conference participants. v CONTENTS (* Asterisk indicates author who presented the talk) Nuclear Spin Response Studies in Inelastic Polarized Proton Scattering • • • • • 1 K. W. Jones Nucleon-Nucleus Scattering to the Continuum • • • • • • • • • • 15 R. D. Smith Relativistic Calculations for Quasi-Elastic Proton Scattering • • • • • • • • • • 53 M. J. Iqbal Spin Excitations in a Schematic Model • • • • • • • • • • 59 P. M. Boucher, B. Castel, Y. Okuhara, I. P. Johnstone, J. Wambach*, and T. Suzuki Spin Observables in Electron Scattering From Nuclei . • • • • • • • • • • 65 T. W. Donnelly Spin Observables in Exclusive Electron Scattering 79 J. W. Van Orden Relativistic Treatment of Mesonic COntributions to Quasielastic (e,e') •••••• 95 P. G. Blunden* and M. N. Butler The (p,2p) Reaction in the Dirac Impulse Approximation • • • • • • • • 101 E. D. Cooper* and o. V. Maxwell Spin-observables for the (p,p'y) Reaction at 400 MeV III K. H. Hicks Proton Induced Delta Production 119 B. K. Jain The (n,p) Reaction as a Probe of Nuclear Structure 139 K. P. Jackson* and A. Celler (p,n) Measurements Above 200 MeV and the Isovector Effective NN Interaction •••••••••• 155 R. G. Jeppesen vii Spin-Isospin Excitations in Nuclei and (p,n) Reactions • • • • • • • • • • • • • • • 169 S. N. Ershov, F. A. Gareev, N. I. Pyatov* and S. A. Fayans 'Isovector Spin Observables in Nuclear Charge-Exchange Reactions at LAMPF ••• • • • • • • • • • • • 183 J. B. MCClelland New Neutron Time-of-Flight (NTOF) Facilities at the Brookhaven 2DO-Mev Linac •••••••• 195 T. E. Ward*, J. Alessi, J. Brennan, P. Grand R. Lankshear, C. L. Snead, N. Tsoupas and M. Zucker The 208pb(p,n)208Bi Reaction at 135 MeV • • • • • • • • • 199 J. W. watson*, M. R. Plumley, P. J. Pella, B. D. Anderson, A. R. Baldwin, R. Madey, and C. C. Foster Spin-Isospin Modes in Quasi-Free Region. • • • • 207 M. Ichimura*, K. Kawahigashi, T. S. Jorgensen and C. Gaarde Charge Exchange Reactions at Saturne 221 C. Ellegaard Spin-Isospin Response of a Nucleon at High Excitation Energy • • • • • • • • • • • • • • • 231 V. F. Dmitriev 3 4 Momentum Distributions of Fragments of D, He, and He Nuclei and T20 in 00 Deuteron Break-Up 241 V. G. Ableev, B. Naumann, L. Naumann, A. A. Nomofilov, L. Penchev, N. M. piskunov, V. I. Sharov, I. M. Sitnik, E. A. Strokovsky, L. N. Strunov*, S. A. Zaporozhets, A. P. Kobushkin, Kh. Oimitrov, L. Vizireva, B. Kuhn, and W. Neubert Ratio ~~ ~w-Teller to Fermi Strength Observed in , C(p,n) at 492 and 590 MeV •• • • • • • 245 J. L. Ullmann*, J. Rapaport, P. W. Lisowski, R. C. Byrd, T. Carey, T. N. Taddeucci, J. McClelland, L. Rybarcyk, R. C. Haight, N.S.P. King, G. L. Morgan, D. A. Lind, R. Smythe, C. D. Zafiratos, D. Prout, E. Sugarbaker, W. P. Alford, and W. G. Love Spin-Isospin Nuclear Responses with Hadronic Probes • • • • • • 251 W. M. Alberico Wigner-Kirkwood Expansion of the Quasi-Elastic Nuclear Responses and Application to Spin-Isospin ResJ;X>nses ••••••••••••••••••• 261 G. Chan fray The Relativistic Nuclear Response and Vacuum Polarization • • • 269 C. J. Horowitz Dirac RPA for Finite Nuclei 285 J. R. Shepard viii Relativistic RPA calculations in Finite Nuclei: Results ••••••••• 301 R. J. Furnstahl Charge Exchange (P,N) Reactions to the Isobaric Analog State • • • • • • • • • • • • • • • 321 S. Hama*, M. J. Iqbal, J. I. Johansson and H. S. Sherif Validity of the Hartree Approximation in the Walecka Model •••••••• 329 R. J. Perry A Relativistic Description of Deformed Nuclei 339 C. E. Price Violent Collisions of Spinning Protons • • • • • • • • • • • • 351 A. D. Krisch A Status Report on the "t20" Experiment at Bates: Toward a Separation of the Charge and Quadrupole Form Factors of the Deuteron • • • • • • • • • • • • • • • • • • • • 357 M. Garcon*, L. antonuk, J. Arvieux, D. Beck, E. Beise, A. Boudard, E. B. cairns, J. M. cameron, G. Dodson, K. Dow, M. Farkhondeh, H. W. Fielding, R. Goloskie, S. Hoibraten, J. Jourdan, S. Kowalski, C. Lapointe, W. J. McDonald, D. Pham, R. Redwine, N. Rodning, G. Roy, M. E. Schulze, P. A. Souder, J. Soukup, I. The, W. Turchinetz, C. F. Williamson, K. Wilson, S. Wood, and W. Ziegler Physics in the GeV Region with Polarized Targets in Electron Storage Rings •••••••• 371 R. J. Holt Spin Observables in PP Elastic and PP Inelastic Scattering • • • • • • • • • • • 379 R. Bertini Measurement of 2-nd and 3-rd Order Spin Observables in Elastic Scattering of 1.6 GeV Tensor and Vector Polarized Deuteron Beam From a polarized Hydrogen Target •••••••••••••••• 393 V. Ghazikhanian, B. Aas, D. Adams, E. Bleszynski, M. Bleszynski, J. Bystricky, G. J. Igo, F. Sperisen, C. A. Whitten, P. Chaumette, J. Deregel, J. Fabre, F. Lehar, A. de Lesquen, L. van Rossurn, J. Arvieux, J. Ball, A. Boudard, F. Perrot Nuclear Isovector Electroweak Interactions in a Relativistic Model • • • • • 399 G. E. Walker* and M. W. Price Energy Dependent Corrections to Spin Observables in Nucleon-Nucleus Scattering •••••• 417 J. Piekarewicz The Empirical Connection Between (p,n) Cross Sections and Beta Decay Transition Strengths •••••• 425 T. N. Taddeucci ix Summary Talk--International Conference on Spin Observables of Nuclear Probes • 443 G. T. Garvey Contributors • • • • • • • • • • • • • • • • • • • • • • • • • 459 . . . . . . . . . . . . . . . . . . . . . . 461 Index x NUCLEAR SPIN RESPONSE STUDIES IN INELASTIC POLARIZED PROTON SCATTERING Kevin W. Jones Los Alamos National Laboratory Los Alamos, N.M. 87544 ABSTRACT Spin-flip probabilities Snn have been measured for inelastic proton scattering at incident proton energies around 300 MeV from a number of nuclei. At low excitation energies Snn is below the free value. For excitation energies above about 30 MeV for momentum transfers between about 0.35 fm-1 and 0.65 fm-1 Snn exceeds free values significantly. These results = = + = suggest that the relative llS 1/(llS 0 llS 1) nuclear spin response approaches about 90% in the region of the enhancement. Comparison of the data with slab response = calculations are presented. Decomposition of the measured cross sections into (1(llS 0) and = (1(llS 1) permit extraction of nonspin-flip and spin-flip dipole and quadrupole strengths. INTRODUCTION Spin excitations in nuclei have been the subject of considerable theoretical and experi mental work during the past six years. Indeed, much of the work presented here originated in the study of M1 transitions in nuclei, a subject addressed in detail in the 1982 Telluride Conference and in subsequent publications.1-1 The initially strong focus on the distribution of Ml strength excited by proton inelastic scattering has evolved into a more general study of the distribution of spin excitations in nuclei excited with this probe. The program begun at the high resolution proton spectrometer facility (HRS) at LAMPF has been facilitated by the development of a polarimeter facility associated with the medium resolution spectrometer (MRS) at TRIUMF.8,9 The combination of data available from the HRS facility at LAMPF and the MRS at TRIUMF forms a substantial contribution to the study of continuum exci tations by inelastic proton scattering up to about 50 MeV in a variety of nuclei from 12C to 90Zr. The proton is a complex but desirable probe of the nucleus, roughly equally scalar and vector in nature. As such it can be used to excite the full complexity of the nuclear continuum. By contrast, the charge-exchange reaction (p, n) is a probe of purely isovector character; consequently the excitation of the nucleus is selective. The complementarity of these and other probes should result in a detailed understanding of the isospin and spin re sponse of the nucleus. Recent advances in marge-exchange studies addressing the distribution of Gamow-Teller and other isovector strength in nuclei are discussed by other contributors at this conference. EXPERIMENTAL DETAILS Experiments have been carried out at both the HRS at LAMPF and the MRS at TRI UMF. Measurements at the HRS were made with a beam of 319-MeV protons polarized perpendicular to the reaction plane. Scattered particles were detected in the standard HRS focal-plane poiarimeter10 modified to minimize backgrounds inherent in small-angle inelastic scattering. The choice of 319 MeV was dictated by precession considerations in the spec trometer and the relative strength of spin-flip to nonspin-flip components of the effective nucleon-nucleon interaction. Measurements at the MRS were made with a beam of 290-MeV protons polarized perpendicular to the reaction plane. Scattered particles were detected in the standard MRS focal plane polarimeter. Beam polarizations at both facilities were mon itored continuously with in-beam polarimeters, as well as with the quench-ratio technique at the HRS. Absolute normalization of measured cross sections was made by comparison of measured cross sections for proton scattering from hydrogen with extant data and phase shift analyses.l1 Data were taken for scattering from 12C, 40Ca, 48Ca, SlV, and 90Zr at the HRS, and from 44Ca and 54Fe at the MRS. Typical cross-section spectra for inelastic proton scattering around an incident energy of 300 MeV are shown in Fig. 1. 10.0 B.O 64Fe(p,p,)64Fe· 290 MeV 6.0 3.10 % 4.0 '=;:=:;- 2.0 ~ .0 E- 0.0 r:.::J ~c: B.O ~ b N' 0 6.0 15.00 4.0 2.0 0.0 -5 0 5 10 15 20 25 30 35 40 45 Ex (MeV) = Fig. 1. Differential cross section spectra for the 54Fe(p,p')54Fe* reaction at Tp 290 MeV. The data were taken using the MRS facility at TRIUMF at laboratory scattering angles of 3.10 and 150. 2
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