Photopion Nuclear Physics

420 Pages·1979·12.948 MB·English

by  G. E. Brown (auth.), Paul Stoler (eds.)

Photopion
Nuclear
Physics
Edited by
Paul Stoler
Rensselaer Polytechnic Institute
Troy, New York
Plenum Press· New York and London
Library of Congress Cataloging in Publication Data
Main entry under title:
Photopion nuclear physics.
"Based on lectures presented at the International Symposium on Photo
pion Nuclear Physics at Rensselaer Polytechnic Institute, Troy, New York,
August 10-12, 1978."
QC793.5.M422P47 539.7'2162 78-31569
ISBN-13: 978-1-4684-3473-6 e-ISBN-13: 978-1-4684-3471-2
001: 10.1007/978-1-4684-3471-2
Based on Lectures presented at the International Symposium
on.Photopion Nuclear Physics at Rensselaer Polytechnic Institute,
Troy, New York, August 10-12,1978.
©1979 Plenum Press, New York
Softcover reprint of the hardcover 15t edition 1979
A Division of Plenum Publish ing Corporation
227 West 17th Street, New York, N.Y. 10011
All rights reserved
No part of this book may be produced, 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
This volume consists of twelve review articles and a
variety of short contributions which are based on lectures
presented at the International Symposium on Photopion Nuclear
Physics. The review articles were submitted after the sym
posium, and there was considerable editing and cross referen
cing with the aim of achieving a greater overall unity than
ordinarily found in conference proceedings.
Photopion Nuclear Physics, as the name suggests, combines
two of the most active areas of current intermediate energy
nuclear physics research - electromagnetic phenomena as
studied by means of electron scattering and photonuclear pro
cesses, and mesonic effects in nuclei. The potential value of
photopion studies as a complement to electron scattering for
the study of spin-isospin aspects of nuclear transitions has
been widely recognized for about a decade, thanks to the the
oretical work at such institutions as Stanford and Catholic
Universities. In fact, some of this theoretical work was done
in anticipation of the advent of the new high duty cycle and
good energy resolution electron linacs. The potential for
using this reaction to study mesonic effects was not as broad
ly addressed at that time. However, as seen in the following
pages of these proceedings, that situation has dramatically
changed. For example, within thr past two years, theoretical
studies of experiments on D and 2C, done respectively at the
Saclay and Bates electron linacs, have shown a strong sensi
tivity to different aspects of pion-nuclear interactions, so
that these problems have emerged into the forefront of this
field.
The symposium was conceived of at a time when most of the
initial experiments on charged pion production on light nuclei
and pion capture had been completed, and the subsequent agree
ment of the theoretical calculations gave a good degree of
confidence in the basic approach. Diverse higher energy data
v
vi PREFACE
and theoretical calculations (some speculative) were beginning
to appear from various laboratories. It was just about the
right time for a conference to see how it all fits together
and to define some coherent directions for this field.
The proceedings tend to follow the actual format of the
symposium. The first part contains three papers which give a
general review of the field from the theoretical and experi
mental points of view. Each of the next four sections begins
with a review of some specific area of interest, and contains
some contributed papers which are pertinent to that area.
Finally, the summary paper attempts to assess the present sta
tus of the field, and hints at some possible future directions.
There was a very large discussion time during the symposium.
These discussions were not reproduced in the Proceedings. How
ever, as previously indicated, the final versions of all manu
scripts were submitted after the symposium so that each author
could take all the other contributions and the discussions in
to account to some extent. Although there was considerable
editing, very little was substantive, and that only after com
plete consultations with the authors.
Thanks are due to H. A. Medicus and B. Schoch of the or
ganizing committee, as well as to the editor's colleagues. A.
M. Bernstein, K. I. Blomqvist, K. Min, E. J. Winhold and P. F.
Yergin for their work on behalf of the symposium, and to the
International Advisory Committee (A. M. Bernstein, G. E. Brown,
K. M. Crowe, D. Drechsel, H. Feshbach, J. S. O'Connell, K.
Shoda, V. L. Telegdi, C: Tzara, H. Uberall, J. D. Walecka, P.
F. Yergin) for their guidance. Special appreciation goes to
Phyllis Campbell and Clara Gorenstein for their work in over
seeing the day-to-day organizational details, and to Deborah
Maniaci who bore the responsibility for most of the technical
typing in this volume. The editor and organizing committee
are grateful to the United States National Science Foundation,
the United States Department of Energy, the American Physical
Society and Rensselaer Polytechnic Institute for their sponsor
ship. The Digital Equipment Corporation generously supplied
financial aid to help meet the travel expenses of some scien
tists who otherwise could not have attended.
Troy, New York Paul Stoler
November 1978
Contents
(A separate list of contributed papers follows on p. ix.)
INVITED PAPERS
INTRODUCTORY REVIEW 1
G. E. Brown
PHOTOPION PHYSICS - AN EXPERIMENTAL
OVERVIEW ••.••••• 19
E. J. Winhold
RELATIONSHIP OF WEAK AND ELECTROMAGNETIC
PROCESSES TO PHOTOPION
REACTIONS .•.•••..••• 51
T. W. Donnelly
RADIATIVE PION CAPTURE 69
J. P. Perroud
CONTRIBUTED PAPERS 101
TOTAL CROSS SECTION MEASUREMENTS FOR THE
PHOTOPRODUCTION OF CHARGED
PIONS FROM THRESHOLD TO
350 MeV • • • . • • • • • • • • • • • •• 129
E. C. Booth
CONTRIBUTED PAPERS 155
CHARGED PION SPECTROSCOPY • 175
K. Shoda
CONTRIBUTED PAPERS 193
NEUTRAL PION PHOTOPRODUCTION ON NUCLEI
NEAR THRESHOLD • • • • • • • 219
N. de Botton
CONTRIBUTED PAPERS 239
vii
viii CONTENTS
CORRECTIONS TO THE QUASI-FREE PROCESS 255
J. M. Laget
PHOTOPRODUCTION OF CHARGED PIONS
FROM C1 2 USING A TAGGED
PHOTON BEAM • • • • • • 275
J. Arends, J. Eyink, H. Hartmann,
A. Hegerath, B. Mecking, G. NBldeke,
and H. Rost
CONTRIBUTED PAPER • • ••• 295
PION-NUCLEUS INTERACTIONS AND
PHOTOPRODUCTION 301.
F. Tabakin
. . . . . .
CONTRIBUTED PAPER ., 327
PION-NUCLEUS INTERACTIONS IN THE
RESONANCE REGION 335
E. J. Moniz
CONTRIBUTED PAPERS 353
SUMMARY AND OUTLOOK. 405
A. M. Bernstein
LIST OF CONTRIBUrORS 425
LIST OF PARTICIPANTS 429
INDEX • • • • • • • • • 433
CONTENTS ix
CONTRIBUTED PAPERS
INVESTIGATION OF ANALOGS OF Ml, El and M2 TRANSITIONS
IN lOB, 12C and 14N THROUGH RADIATIVE PION CAPTURE. 101
J. C. Alder, W. Dahme, B. Gabioud, C. Joseph,
J. F. Loude, N. Morel, H. Panke, A. Perrenoud,
J. P. Perroud, D. Renker, G. Strassner, M. T.
Tran, P. Truol and E. Winkelmann
RADIATIVE PION CAPTURE IN MEDIUM MASS NUCLEI: 32S, 107
40 Ca • • • • • • • • • • • • • • • • • • • • • • •
J. C. Alder, W. Dahme, B. Gabioud, C. Joseph,
J. F. Loude, H. Medicus, N. Morel, H. Panke,
A. Perrenoud, J. P. Perroud, D. Renker, G.
Strassner, M. T. Tran, P. Truol and E.
Winkelmann
BRANCHING RATIO FOR RADIATIVE PION CAPTURE WITH
RESPECT TO ABSORPTION OF STOPPED NEGATIVE PIONS 111
Carl Werntz
GIANT RESONANCE EXCITATION IN VARIOUS PROCESSES.
13
EXAMPLE: C• . . . . . . . . . . • . . . • • . . 117
H. R. Kissener and R. A. Eramzhyan
NUCLEON SPECTRA FROM THE 160(n-,y) REACTION .. 121
R. A. Eramzhyan, M. Gmitro, L. A. Tosunjan
THE UNIFIED DESCRIPTION OF DIRECT AND RESONANCE
PROCESSES IN THE RADIATIVE PION CAPTURE BY LIGHT
NUCLEI. . . . . • . . • . . . . . 125
V. V. Balashov and R. Wunsch
THEORY OF PION PHOTOPRODUCTION in 12C and 160 155
A. Nagl and H. Uoerall
NEGATIVE PION PHOTOPRODUCTION FROM 28Si
K. Srinivasa Rao and S. Susila
PHOTOPRODUCTION OF n- FROM 14N. . 165
V. DeCarlo, N. Freed, and W. Rhodes
x CONTENTS
A METHOD FOR MEASUREMENTS OF THE TOTAL 2H(y,n-)pp
CROSS SECTIONS AT THRESHOLD. • . • . . . • . • . . 171
B. Schoch, F. Klein and G. LUhrs
STUDY ON THE LOW-LYING STATES VIA THE PHOTOPION
PRODUCTION ON SEVERAL NUCLEI . . . . . . . • 193
H. Ohashi, K. Nakahara, M. Yamazaki, K. Shoda
and B. N. Sung
CHARGED PION ELECTROPRODUCTION ON LIGHT NUCLEI NEAR
THE THRESHOLD. • • • . • • . • . . . . . . . . 199
S. Furui
PHOTOPION ENERGY DISTRIBUTIONS AND SPIN-ISOSPIN
GIANT RESONANCES . . . . . • . . • . . . • • • . 205
K. Shoda, M. Yamazaki, K. Nakahara, H. Ohashi
PION SPECTRA TO INDIVIDUAL FINAL STATES IN THE
12 ± 12 12
REACTIONS C(y,n) B, N. • . . . • . . . • 211
N. Paras, A. M. Bernstein, K. I. Blomqvist,
G. Franklin, J. LeRose, K. Min, M. Pauli,
D. Rowley, B. Schoch, P. Stoler, E. J.
Winhold and P. F. Yergin
A MEASUREMENT OF nO PHOTOPRODUCTION ON 3He and 4He
NEAR THRESHOLD . . . . . . . . . . . . . . . . . 239
P. Argan, G. Audit, A. Bloch, N. de Botton, J. L.
Faure, C. Schuhl, G. Tamas, C. Tzara and E.
Vincent
NEUTRAL PION PHOTOPRODUCTION FROM COMPLEX NUCLEI
NEAR THRESHOLD . . . . . . . . • . . . . . . . 245
F. L. Milder, E. C. Booth, B. L. Roberts,
J. Comuzzi and H. Crannell
249
R. Sridhar, K. Srinivasa Rao and S. Susjla
QUASI-FREE PION PHOTOPRODUCTION FROM COPPER AND LEAD 295
K. Baba, I. Endo, M. Fujisaki, S. Kadota, Y.
Sumi, H. Fujii, Y. Murata, S. Noguchi, A.
Murakami
12 - 12
C(y,TI) Ng.s. FOR (0-50) MeV PIONS •. 327
G. N. Epstein, M. K. Singham and F. Tabakin
CONTENTS xi
COHERENT o PHOTOPRODUCTION IN THE ISOBAR-HOLE
TI
FORMALISM. . . • . . • • • . • . . . • . . . • 353
J. H. Koch and E. J. Moniz
UNIFIED DESCRIPTION OF PION-PHOTOPRODUCTION AND
ELASTIC PION SCATTERING ON THE DEUTERON IN THE
ISOBAR-DOORWAY MODEL . . . . . . • . . . . 361
R. Handel, M. Dillig and M. G. Huber
A SUM RULE DESCRIPTION FOR THE INCLUSIVE ELECTROPRO-
DUCTION OF PIONS FROM NUCLEI ......•.•.• 367
R. Rosenfelder
INCLUSIVE ELECTROPRODUCTION OF LOW ENERGY PI MESONS. 371
M. Pauli, A. M. Bernstein, K. I. Blomqvist,
G. B. Franklin, J. LeRose, K. Min, N. Paras,
D. Rowley, B. Schoch, P. Stoler, E. J.
Winhold and P. F. Yergin
PHOTOPION PRODUCTION IN THE FERMI GAS MODEL. 381
J. S. O'Connell, W. M. MacDonald and E. T.
Dressler
TOTAL PHOTONUCLEAR ABSORPTION CROSS SECTIONS FOR
Li and Be UP TO 350 MeV ..••......•..
J. Ahrens, H. Gimm, R. J. Hughes, R. Leicht, P.
Minn, A. Zieger and B. Ziegler
ISOMERIC AND GROUND STATE FORMATION IN 197Hg BY THE
197 ( - 197
Au y,n) Hg REACTION NEAR THRESHOLD. • • • • •• 387
P. H. Ballentine, J. K. Hersh, H. A. Medicus,
S. Planeta, E. Potenziani and S. Rossdeutscher
INVESTIGATION OF THE CHARGE EXCHANGE PROCESS n-d + 391
H.-T. Cheon
PION-ELECTROPRODUCTION FROM SINGLE NUCLEONS. 395
H. B. Miska
DEEP INELASTIC ELECTRON SCATTERING NEAR AND ABOVE
PION THRESHOLD. . . . . • . • . • . • . . . . . • 399
P. D. Zimmerman and C. F. Williamson
INTRODUCTORY REVIEW
*
G. E. Brown
State University of New York. Stony Brook. NY
and NORDITA. Copenhagen
I. INTRODUCTION
Photopion physics is several decades old. but its applica
tion to nuclear structure is in its infancy. In this introduc
tion I wish first to review what is known about photopion pro
duction on nucleons at threshold. where firm statements of the
theoretical predictions can be made. and then to extend the
discussion to higher-energy regimes. where models have to be
used. In particular. we shall discuss the isobar-doorway model
and its relationship to the optical model.
As examples of nuclear structure studies. we shall discuss
~ production by y-rays on C12• where good experiments and
careful theoretical analyses have been carried out.
The use of photo- and electropion production to study
nucleon-isobar interactions will be discussed.
II. LOW ENERGY THEOREMS
Current algebra gives very definite predictions for the
photoproduction of pions near threshold. To lowest order in I
m 1m the threshold production is given by the Kroll-Ruderman
n
~
result. This result also follows from gauge invariance in the
following simple way.
The interaction of low-energy pions with nucleons is given
by pseudo-vector coupling