[Phi] Production and the OZI Rule in [Greek Letter Pi Superscript +]D Interactions at 10 Gev/C Joel Stephen Hendrickson Iowa State University
Total Page:16
File Type:pdf, Size:1020Kb
Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1981 [Phi] production and the OZI rule in [Greek letter pi superscript +]d interactions at 10 GeV/c Joel Stephen Hendrickson Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Elementary Particles and Fields and String Theory Commons Recommended Citation Hendrickson, Joel Stephen, "[Phi] production and the OZI rule in [Greek letter pi superscript +]d interactions at 10 GeV/c " (1981). Retrospective Theses and Dissertations. 7428. https://lib.dr.iastate.edu/rtd/7428 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This was produced from a copy of a document sent to us for microfilming. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the material submitted. The following explanation of techniques is provided to help you understand markings or notations which may appear on this reproduction. 1. The sign or "target" for pages apparently lacking from the document photographed is "Missing Page(s)". If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting through an image and duplicating adjacent pages to assure you of complete continuity. 2. When an image on the film is obliterated with a round black mark it is an indication that the film inspector noticed either blurred copy because of movement during exposure, or duplicate copy. Unless we meant to delete copyrighted materials that should not have been filmed, you will find a good image of the page in the adjacent frame. If copyrighted materials were deleted you will find a target note listing the pages in the adjacent frame. 3. When a map, drawing or chart, etc., is part of the material being photo graphed the photographer has followed a definite method in "sectioning" the material. It is customary to begin filming at the upper left hand corner of a large sheet and to continue from left to right in equal sections with small overlaps. If necessary, sectioning is continued again—beginning below the first row and continuing on until complete. 4. For any illustrations that cannot be reproduced satisfactorily by xerography, photographic prints can be purchased at additional cost and tipped into your xerographic copy. Requests can be made to our Dissertations Customer Services Department. 5. Some pages in any document may have indistinct print. In all cases we have filmed the best available copy. Universi^ MicnSilms International 300 N /fc t H HD , ANN AHBUH MMHI06 8209128 Hendrickson, Joel Stephen PHI PRODUCTION AND THE OZI RULE IN POSITIVE PION(D) INTERACTIONS AT 10 GEV/C lom State University PH.D. 1981 University Microfilms Intsrnâtionâl 3% X. Z«* Road Ann Aitor. MI 49106 PLEASE NOTE: In all cases this material has been Aimed in the best possible way from the available copy. Problems encountered with this document have been identified here with a check mark V . 1. Glossy photographs or pages 2. Colored illustrations, paper or print 3. Photographs with dark t>ackground 4. Illustrations are poor copy 5. Pages with black marks, not original copy 6. Print shows through as there is text on both sides of page 7. Indistinct, broken or small print on several pages 8. Print exceeds margin requirements 9. Tightly bound copy with print lost in spine 10. Computer printout pages with indistinct print 11. Page(s) lacking when material received, and not available from school or author. 12. Page(s) seem to be missing in numbering only as text follows. 13. Two pages numbered . Text follows. 14. Curling and wrinkled pages 15. Other University Microfilms International : production and the OZI rule in interactions at 10 GeV/c by Joel Stephen Hendrickson A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Department: Physics Major: High Energy Physics Approved: Signature was redacted for privacy. CT^rge of-^Ma^af Work Signature was redacted for privacy. For the Major Department Signature was redacted for privacy. For the Graduate College Iowa State University Ames, Iowa 1981 11 TABLE OF CONTENTS Page CHAPTER 1. INTRODUCTION 1 CHAPTER 2. THEORY 3 CHAPTER 3. EQUIPMENT 25 CHAPTER 4. TRIGGERING AND DATA ACQUISITION 46 CHAPTER 5. EVENT RECONSTRUCTION 55 CHAPTER 6. DATA ANALYSIS AND MONTE CARLO 69 CHAPTER 7. RESULTS 79 APPENDIX 111 BIBLIOGRAPHY 132 1 CHAPTER 1. INTRODUCTION The recent discovery of numerous heavy particles with abnormally small hadronic decay widths has naturally motivated a search for a mechanism that suppresses these hadronic decay modes. The Okubo-Zwelg- Ilzuka (OZI) rule (1-4) predicts the suppression of these decay modes and is currently the accepted explanation. However, the OZI rule was originally only an ansatz and as yet its dynamical origin is not fully understood. If the OZI rule were exact, the suppression would be com plete; however, the fact that these decay modes are observed indicates that the OZI rule is violated. The dynamical mechanism for the suppres sion cannot be understood until the degree of violation has been measured and it is to this end that the present experiment has measured the cross sections for the reactions m n ^ #p and it p ->•((>A both of which are forbidden by the OZI rule. A history of the OZI rule and a discussion of the status of current theoretical models of the dynamical origin of the OZI rule are presented in Chapter 2. The experiment was conducted ar the Stanford Linear Accelerator Center (SLAC) Large Aperture Solenoid Spectrometer (LASS) facility and involved approximately five million primary physics triggers. A descrip tion of the apparatus is presented in Chapter 3. The experiment was designed to study reactions with final states involving kaons; thus, the trigger selected events with at least one fast forward particle with a mass greater than the pion mass. The trigger logic and data acquisition ? system are discussed in Chapter 4. Chapter 5 presents the method used for reconstructing the events and Chapter 6 describes the data analysis and the Monte Carlo. The results of the cross section measurements for the reactions IT n -*• $p and TT p ->• ij)A are presented in Chapter 7 and the degree of violation of the OZI rule which these measurements repre sents is interpreted in terms of the various theoretical models pre sented in Chapter 2. Also, included in this chapter are the results of a search for the reaction ^r^n -* K%A° which provides a unique study of the OZI rule since it contains both an OZI allowed diagram and an OZI forbidden diagram. The 4), and A° are not detected directly but rather inferred from their detected decay products; * -<• K^K , -+ pw^\ A -• pit . Finally, the results of a search for the phi-prime meson, the first excited state of the ss system, are presented. 3 CHAPTER 2. THEORY At the present time, there is no theoretical consensus of the OZl rule. There are a number of models proposing a dynamical origin of the OZl rule; however, the predictions from most of these models are not sufficient to distinguish among them. The models may be grouped into two categories - those based on QCD and those based on unitarity and duality. A brief statement of several of the more popular of these models is presented in this section. First, however, a short history of the OZl rule is given in order to define the OZl rule. History The wide popularity of the SU(3) model (5) of Gell-Mann is par tially due to the success of the mass formulae. For instance, the formula Y Im(N) + m(5)] » ^ [3m(A) + m(Z)] for the jP - Y baryon octet agrees well with experiment. However, the corresponding formula for the vector meson octet m^(wg) » -J [4m^(K ) - m^(p)l (where Wg is the eighth component of the octet) doesn't fare so well. Putting in the experimental masses (6) for the K and the p, this equation predicts the mass of the I = Y = 0 member of the octet (wg) to be m(wg) • 928 MeV. However, neither of the two particles having the quantum numbers necessary for that state are of the correct mass - 4 namely, the * which has a mass of m(*) - 1020 MeV and the w which has a mass of m(w) • 783 MeV. In 1962, Sakurai (7) suggested that the physical w and * be linear combinations of the eighth component of the octet (w_) and the SU(3) O singlet state (w^). 0) « (Dg sin0 + CO80 * " Wg COS0 - sin6 Using the experimental w and (p masses, the mixing angle (6) is deter mined to be 0 » 40° +1°. A number of predictions from this model agree well with experiment so some confidence was placed in the model. However, it also produced the following problem. The ratio of coupling constants in $ ^ pw and oi pir can be estimated from experimental data 2 to be (8) (g^p^/gyp^) = 0.007. Sakurai's mixing model, however, requires the ratio of coupling constants to be given by 8»pn _ gg cose - g^ sin0 Swpm " «8 + «1 In order to get the small value observed experimentally for this ratio, there has to be a large cancellation in the numerator.