DOCSLIB.ORG

Strange and Non-Strange Particle Production in Proton—Proton Reactions at an Incident Momentum of 19 Gev/C Uno Svedin

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Strange and Non-Strange Particle Production in Proton—Proton Reactions at an Incident Momentum of 19 Gev/C Uno Svedin Strange and Non-Strange Particle Production in Proton—Proton Reactions at an Incident Momentum of 19 GeV/c Uno Svedin Stockholm 1974 Strange and Non-Strange Particle Production in Proton—Proton Reactions at an Incident Momentum of 19 GeV/c Uno Svedin Stockholm 1974 ISBN <i\ 7222 000-6 Sim.li Olfvei Stockholm 74 CONTENTS 1. The scope of this thesis 7 2. Introduction 11 3. Earlier studi^B of proton-proton reactions 17 4. Experimental procedures 18 5. Resume's of publications belonging to this thesis 21 0. Discussion on some physical items related to our investigations 31 6.1 Integrated cross sections 31 6.2 Average multiplicities 34 6.3 The charge multiplicity distribution 39 6.4 Scaling properties of momentum spectra 47 7. Summary 53 8. Acknowledgement 56 9. References 58 Tables List of figures Figures- 1. THE SCOPE OF THIS THESIS The present thesis is based on studies done within the framework of the Scandi- navian Bubble Chamber Collaboration during the years 1966-1974 and concerns different aspects of proton-proton reactions at an incident beam momentum of 19 GeV/c. The presentation is divided into three different parts I. Studies of final states involving non-strange particles. II. Studies of final states involving strange particles. III. Development of equipment. The main emphasis is on the presentation of atrange particle production results (Section II of papers). The results have not been discussed in the form of a thesis before. The sample from which the results are drawn is one of the largest presented up to this day for proton-proton reactions. In the discussion on the production of strange particles we make frequent use of the non-strange final state results. As many aspects of high energy physics do not show their significance except in a study over a wide range of initial energies, We will in the discussion (after a short introduction, a survey on the experimental procedure and resume's of the included papers), frequently make use of data from other ejqperiments, at other energies, of compilations earlier presented by,different.physisists,, (often using our data in part) and of model discussions by various 'authors. The main aim is to explain how our data and conclusions have fitted into the pattern of existing high energy physics results. In order to perform any experimental work, developments of & technical nature must take place. In Paper 111:1 the development of an on line system for measuring bubble chamber pictures is described. A part of the strange particle sample has been measured using this system. Paper 111:1 was earlier included in S-O. Holmgrens thesis [l]. Work to improve the quality of the sample is described in Paper 11:3. Publications included in this thesis are 1:1 H. Bjzfggild, E. Dahl-Jensen, K.H. Hanseji, H. Johnstad, E. Lohse, R. Mbllerud, M. Suk, L. Veje, V.J. Karimaki, K.V. Laurikainen, E. Riipinen, T. Jacobsen, S.O. Sjirensen, J, Allan, G. Blomqvist, O. Danielsson, G. Ekspong, L. Granstrom, S.O. Holmgren, S. Nilsson, B. Ronne, U. Svedin and N.K. Yamdagni: "Some features of particle multiplicities and momentum spectra in inelastic proton-proton colli- sions at 19 GeV/c."Nucl. Phys. B27, 285 (1971). II. II. 1 K. Alpgard, T. Buran, H. B^ggild, A.G. Frodesen, V.M. Haginan, K.H. Hansen, J.E. Hooper, P.O. Hulth, H. Johnstad, M. Korkea-Aho, K. Marquit, R. Moller, U. Svedin, II. Tttfte, P. Villanen and N. Yam- uatiiii: "The inclusive single-partible spectra of ff~, K and A in prolon-proton collisions at 19 GcV/c." Nucl. Phys. B57.. 77-99 (1973). II.2 K. Alpgdrd, G. Ekspong, A-G. Frodesen, V.M. Hagman, P.O. Hulih, V. Kp.rimi.ilci. A. Krogstad, L1. Svedin, P. Villanen and N.K. Yamdagni: "Strange particle cross sections in 19 GeV/c proton-proton interactions and their interpretation in the KNO framework." USIP-Rsport. 74-24 November 1974. 11:3 K. Alpg&rd, P.O. Hulth. U. Svedin and N.K. Yamdagni: Measurements of strange particle production cross sections in proton-proton reactions at 19 GeV/c incident momentum. USIP-Report 74-25, November 1S74. 11:4 The Scandinavian Bubble Chamber Collaboration and the K Coliabora- 4- tion: Factorization in the inclusive reactions pp -• A +Xand K p - A+ X. USIP-Report 74-26, November 1974. Hi. 111:1 G. Blomqvist, S.O. Holmgren, P.O. Hulth and U. Svedin: A hardware system for measurements of bubble chamber films on-line. USIP-Report 70-03, June 1970. 11 2. INTRODUCTION A dominant feature of hadron collisions above a few hundred MeV/c incident momentum (17-threshold) is the creation of new particles. In proton-proton reactions at 19 GeV/c, such creations occur in « 75 % of all reactions. Fig. 1 shows this inelastic part as well as the total cross sections as a func- tion of the incident laboratory momentum for proton-proton re. 3tions. We observe that a large fraction of the total cross section involves the creation of new particles over a wide range of incident momenta. The produced particles could be of several types: ft , K , K , p, p, +-0 I , A, etc. There are certain restrictions on the production of these par- ticles in the form of conservation laws, as the conservation of charge, energy, baryon number etc. The earliest identification of an event of what we now call strange particles was reported by L, Le Prince-Kinguet in 1944 [2]. It was discovered in a cloud chamber exposed to cosmic rays. The mass of the particle was found to be 2 500 ± 50 MeV/c . Such a particle is called a K-meson today. In 1947 Rochester and Butler [3] , found two cases of "forked" (or V-like) tracks in a cloud cham- ber . One of them was interpreted as the decay of a new type of uncharged elementary particle decaying into two lighter charged ones. The mass was estimated to be of the order of 1000 electron masses. Today we know there are two types of V°-particIes called A and K°. After extensive work in many labora- tories this was definitely established by R.W. Thompson et al. [4]. Whereas the strange particles were produced copiously (a 1 %..of the ff-meson _HQ . production), they had lifetimes > 10 sec. From the production cross section it 12 was derived that the matrix element, e.g. for A production, should be of the order of one-third of that of the Yukawa interaction. Thus assuming the same mechanism which produces the V-particles also to be instrumental in their decay, —22 12 one would estimate lifetimes of the order of 10" seconds, a number of 10 smaller than the experimental one. Due to this puzzle the particles were called "strange". Pais [5] solved this difficulty by suggesting that the production of strange par- ticles occurs in pairs only. The decay and production processes thus involve different particles and cannot be simply related. Experiments in 1953 , including the first artificial production of K's at the new cosmotron at Brookhaven [6], established that the production of V s(K or A) occurs in pairs only - "associated production" [7]. This whole subject was systematized in 1953 by Gell Mann [8] and almost simul- taneously by Nakano and Nishijima [9]. They introduced a new additive quantum number, later called strangeness [10], which was postulated to be conserved in strong interactions. Particles given strangeness quantum number not equal to zero were accordingly called "strange particles". Strict conservation of "strange- ness" in strong interactions corresponds to "associated production" of V-particles. A strangeness breaking decay is not possible via strong interaction. Such a decay is however possible via weak interactions, thus giving the long life times observed. In the presently accepted classification scheme for elementary particles, based on group theoretical considerations (SU_) (introduced by Y. Ne'emanand M. Gell-Mann), the strangeness number is one of the Important classification *- properties for particles. 13 During the last years more and more interest has been shown in questions on the general dynamics of reactions (questions of duality, Regge and Pomeron ex- changes, scaling, etc.). Studies of the behaviour of strange particle3 have con- tributed to the understanding of high energy phenomena. The present thesis deals with the production of strange particles produced in proton-proton interactions at an incident momentum of 19 GeV/c. It also com- pares the production of strange particles with the production of non-strange particles also produced in 19 GeV/c pp-reactions. The experiment was performed using the CERN Proton Synchrotron (PS) giving beam momenta up to *» 28 GeV/c. In order to get a fair amount of strange particlb events we collected at the Bubble Chamber exposures (described be- low) around ra500 000 pictures. After the new generation of high energy proton accelerators came into opera- tion (at Serpukov, USSR, pT ._ up to 70 GeV/c, at NAL, Batavia, USA, p_ up to fa 400 GeV/c, at CERN ISR up to a corresponding incident momentum of« 1500 GeV/c), a set of experiments studying strange and non-strange production in proton-proton reactions have been performed. Many of these experiments have studied a small sample of pictures (a few tens,of thousands) giving large .'•-.. statistical errors. The restricted number of pictures is however somewhat compensated, what the strange purtiole production concerns, by the increasing . cross sections. ' • •'.'••' :'••'••'•'•.'". '"\: '• •••'_••, ..;:' •'.. • ' • • • • 1 ' - •'**•.• A reaction ; • A •F13Jfch.+:ch; + .";r.ch' •••+--N-VN- Vi.-. N-' .1 z • n. i .4 m 14 (A is the beam and B is the target particle, Ch .
Load more

Recommended publications
  • The Role of Strangeness in Ultrarelativistic Nuclear
    HUTFT THE ROLE OF STRANGENESS IN a ULTRARELATIVISTIC NUCLEAR COLLISIONS Josef Sollfrank Research Institute for Theoretical Physics PO Box FIN University of Helsinki Finland and Ulrich Heinz Institut f ur Theoretische Physik Universitat Regensburg D Regensburg Germany ABSTRACT We review the progress in understanding the strange particle yields in nuclear colli sions and their role in signalling quarkgluon plasma formation We rep ort on new insights into the formation mechanisms of strange particles during ultrarelativistic heavyion collisions and discuss interesting new details of the strangeness phase di agram In the main part of the review we show how the measured multistrange particle abundances can b e used as a testing ground for chemical equilibration in nuclear collisions and how the results of such an analysis lead to imp ortant con straints on the collision dynamics and spacetime evolution of high energy heavyion reactions a To b e published in QuarkGluon Plasma RC Hwa Eds World Scientic Contents Introduction Strangeness Pro duction Mechanisms QuarkGluon Pro duction Mechanisms Hadronic Pro duction Mechanisms Thermal Mo dels Thermal Parameters Relative and Absolute Chemical Equilibrium The Partition Function The Phase Diagram of Strange Matter The Strange Matter Iglo o Isentropic Expansion Trajectories The T ! Limit of the Phase Diagram
    [Show full text]
  • Strange Particle Theory in the Cosmic Ray Period R
    STRANGE PARTICLE THEORY IN THE COSMIC RAY PERIOD R. Dalitz To cite this version: R. Dalitz. STRANGE PARTICLE THEORY IN THE COSMIC RAY PERIOD. Journal de Physique Colloques, 1982, 43 (C8), pp.C8-195-C8-205. 10.1051/jphyscol:1982811. jpa-00222371 HAL Id: jpa-00222371 https://hal.archives-ouvertes.fr/jpa-00222371 Submitted on 1 Jan 1982 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. JOURNAL DE PHYSIQUE Colloque C8, suppldment au no 12, Tome 43, ddcembre 1982 page ~8-195 STRANGE PARTICLE THEORY IN THE COSMIC RAY PERIOD R.H. Dalitz Department of Theoretical Physics, 2 KebZe Road, Oxford OX1 3NP, U.K. What role did theoretical physicists play concerning elementary particle physics in the cosmic ray period? The short answer is that it was the nuclear forces which were the central topic of their attention at that time. These were considered to be due primarily to the exchange of pions between nucleons, and the study of all aspects of the pion-nucleon interactions was the most direct contribution they could make to this problem. Of course, this was indeed a most important topic, and much significant understanding of the pion-nucleon interaction resulted from these studies, although the precise nature of the nucleonnucleon force is not settled even to this day.
    [Show full text]
  • Detection of a Strange Particle
    10 extraordinary papers Within days, Watson and Crick had built a identify the full set of codons was completed in forensics, and research into more-futuristic new model of DNA from metal parts. Wilkins by 1966, with Har Gobind Khorana contributing applications, such as DNA-based computing, immediately accepted that it was correct. It the sequences of bases in several codons from is well advanced. was agreed between the two groups that they his experiments with synthetic polynucleotides Paradoxically, Watson and Crick’s iconic would publish three papers simultaneously in (see go.nature.com/2hebk3k). structure has also made it possible to recog- Nature, with the King’s researchers comment- With Fred Sanger and colleagues’ publica- nize the shortcomings of the central dogma, ing on the fit of Watson and Crick’s structure tion16 of an efficient method for sequencing with the discovery of small RNAs that can reg- to the experimental data, and Franklin and DNA in 1977, the way was open for the com- ulate gene expression, and of environmental Gosling publishing Photograph 51 for the plete reading of the genetic information in factors that induce heritable epigenetic first time7,8. any species. The task was completed for the change. No doubt, the concept of the double The Cambridge pair acknowledged in their human genome by 2003, another milestone helix will continue to underpin discoveries in paper that they knew of “the general nature in the history of DNA. biology for decades to come. of the unpublished experimental results and Watson devoted most of the rest of his ideas” of the King’s workers, but it wasn’t until career to education and scientific administra- Georgina Ferry is a science writer based in The Double Helix, Watson’s explosive account tion as head of the Cold Spring Harbor Labo- Oxford, UK.
    [Show full text]
  • Negative Strange Quark-Chemical Potential a Necessary and Sufficient Observable of the Deconfinement Phase Transition in a Finite-Baryon Equilibrated State*
    Negative strange quark-chemical potential A necessary and sufficient observable of the deconfinement phase transition in a finite-baryon equilibrated state* Apostolos D. Panagiotou and Panayiotis Katsas University of Athens, Physics Department Nuclear & Particle Physics Division Panepistimiopolis, GR-157 71 Athens, Hellas Abstract We consider the variation of the strange quark-chemical potential in the phase diagramme of nuclear matter, employing the order parameters and mass-scaled partition functions in each domain and enforcing flavour conservation. Assuming the region beyond the hadronic phase to be described by massive, correlated and interacting quarks, in the spirit of lattice and N−J-L calculations, we find the strange quark-chemical potential to attain large negative values in this domain. We propose that this change in the sign of the strange quark- chemical potential, from positive in the hadronic phase to negative in the partonic, to be a unique, concise and well-defined indication of the quark-deconfinement phase transition in nuclear matter. We propose also that, for a chemically equilibrated state in the deconfined region, which follows an isentropic expansion to hadronization via a second order phase transition, the fugacities of the equilibrated quark flavours, once fixed in the primordial state, remain constant throughout the hadronization process. PACS codes: 25.75.+r,12.38.Mh,24.84.+p Key words: Quark-chemical potential, phase transition, deconfined quark matter, HG, QGP e-mail: [email protected] * Work supported in part by the Research Secretariat of the University of Athens. 1. Introduction It is generally expected that ultra-relativistic nucleus-nucleus collisions will provide the basis for strong interaction thermodynamics, which will lead to new physics.
    [Show full text]
  • Charged Current Events with Neutral Strange Particles in High-Energy Antineutrino Interactions
    Nuclear Physics B177 (1981) 365-381 O North-Holland Publishing Company CHARGED CURRENT EVENTS WITH NEUTRAL STRANGE PARTICLES IN HIGH-ENERGY ANTINEUTRINO INTERACTIONS V.V. AMMOSOV, A.G. DENISOV, P.F. ERMOLOV, G.S. GAPIENKO, V.A. GAPIENKO, V.I. KLUKHIN, V.I. KORESHEV, P.V. PITUKHIN, V.I. SIROTENKO, E.A. SLOBODYUK, Z.V. USUBOV and V.G. ZAETZ Institute of High Energy Physics, Serpukhov, U$SR J.P. BERGE, D. BOGERT, R. ENDORF 1, R. HANFT, J.A. MALKO, G.I. MOFFATT 1, F.A. NEZRICK, R. ORAVA and J. WOLFSON Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA V.I. EFREMENKO, A.V. FEDOTOV, P.A. GORICHEV, V.S. KAFTANOV, G.K. KLIGER, V.Z. KOLGANOV, S.P. KRUTCHININ, M.A. KUBANTSEV, I.V. MAKHLJUEVA, V.I. SHEKELJAN and V.G. SHEVCHENKO Institute for Theoretical and Experimental Physics, MosCow, USSR J. BELL, C.T. COFFIN, B.P. ROE, A.A. SEIDL, D. SINCLAIR and E. WANG University of Michigan, Ann Arbor, Michigan 48104, USA Received 23 May 1980 (Revised 5 August 1980) The results of a study of strange particle production in charged current 77,N interactions in the Fermilab 15 ft bubble chamber filled with a heavy Ne-H2 mixture are presented. Production rates and average multiplicities of K°'s and A's as functions of W 2 and Q2 are given. The experimental data agree well with the quark-parton model predictions if a yield of 0.06 + 0.02 of K°'s and A's from charm production is included. Upper limits for D-meson production are given and the shape of the charmed quark fragmentation function is discussed.
    [Show full text]
  • Astrophysical Relevance of Strange Quarks
    Available online a t www.scholarsresearchlibrary.com Scholars Research Library Archives of Physics Research, 2010, 1 (3):89-110 (http://scholarsresearchlibrary.com/archive.html) ISSN 0976-0970 CODEN (USA): APRRC7 Astrophysical relevance of Strange Quarks Navjot Hothi† and Shuchi Bisht * Department of Physics, Kumaun University, Nainital, Uttrakhand, India ______________________________________________________________________________ ABSTRACT In this contribution, peculiarities in the nature of strange quarks in relevance to astrophysics are investigated. The absolute stability of strange quark matter is a viable possibility and immensely affects physics at the astrophysical scale. Relativistic heavy-ion reactions offer a stage to produce this exotic state of matter and we have discussed the enhanced production of strange particles during these reactions within the framework of quark-gluon plasma (QGP) along with its observable implications. The role of strangeness for compact star phenomenology is explored. Emphasis is laid upon the possibility of existence of a third family of strange quark stars and its study help in revealing a number of unexplored features of the cosmos. Bag model parameters have been used to determine some integral parameters for a sequence of strange stars with crust and strange dwarfs constructed out of strange quark matter crust. A comparative analysis is performed between the strange and neutron stars and the strange and white dwarfs based upon these intrinsic parameters and paramount differences are observed. PACS numbers: 12.38.Mh, 25.75.Nq, 14.65.-q, 97.60.Jd, 26.60.-c Keywords: strangeness, strange stars, quark-gluon plasma, deconfinement. ______________________________________________________________________________ INTRODUCTION The last few years witnessed the inclusion of strangeness as another degree of freedom in astrophysical systems.
    [Show full text]
  • 1 Historical Introduction to the Elementary Particles
    13 1 Historical Introduction to the Elementary Particles This chapter is a kind of ‘folk history’ of elementary particle physics. Its purpose is to provide a sense of how the various particles were first discovered, and how they fit into the overall scheme of things. Along the way some of the fundamental ideas that dominate elementary particle theory are explained. This material should be read quickly, as background to the rest of the book. (As history, the picture presented here is certainly misleading, for it sticks closely to the main track, ignoring the false starts and blind alleys that accompany the development of any science. That’s why I call it ‘folk’ history – it’s the way particle physicists like to remember the subject – a succession of brilliant insights and heroic triumphs unmarred by foolish mistakes, confusion, and frustration. It wasn’t really quite so easy.) 1.1 The Classical Era (1897–1932) It is a little artificial to pinpoint such things, but I’d say that elementary particle physics was born in 1897, with J. J. Thomson’s discovery of the electron [1]. (It is fashionable to carry the story all the way back to Democritus and the Greek atomists, but apart from a few suggestive words their metaphysical speculations have nothing in common with modern science, and although they may be of modest antiquarian interest, their genuine relevance is negligible.) Thomson knew that cathode rays emitted by a hot filament could be deflected by a magnet. This suggested that they carried electric charge; in fact, the direction of the curvature required that the charge be negative.
    [Show full text]
  • Significance of Strangeness Conservation/Violation Studies at BESIII
    Proceedings of the Pakistan Academy of Sciences: Pakistan Academy of Sciences A. Physical and Computational Sciences 55 (2): 1–11 (2018) Copyright © Pakistan Academy of Sciences ISSN: 2518-4245 (print), 2518-4253 (online) Review Article Significance of Strangeness Conservation/Violation Studies at BESIII Aneela Amin1 , Khadija Saeed1, Farzana Younas1, and Ghalib ul Islam2 ∗ 1Centre for High Energy Physics, University of the Punjab, Lahore (54590), Pakistan 2Department of Physics, The University of Lahore, Lahore (53700), Pakistan Abstract Strangeness violation and conservation have been studied in Charmonia and its higher state decays. The data of some prominent decay modes has been collected from BESIII laboratory from the years 2009 to date. The strangeness violating decays play an important role in the study of weak interactions. On the other hand, strangeness conserving decays describe the strong interactions. An overview of strangeness conserving decays and strangeness violating decays has been given and the decay modes are presented in tabular form. The study reveals that associated production occurs only in strangeness conserving decays rather than strangeness violating decays. Experimental and theoretical results are presented in order to arrange phenomenological developments and queries may search new domains in Experimental High Energy Physics, and will explore new prospects of strangeness, a basic quantum number of hadrons and its associated production. Keywords: Strangeness, Charmonia, Strangeness conserving decays, Strangeness violating decays, Standard model 1. INTRODUCTION described the interactions among these particles known as Standard Model. According to The study of particles and the interaction between Standard Model, three types of interactions exist them shows that quarks and leptons are the basic among these particles i.e.
    [Show full text]
  • Strange Hadron Production in Heavy Ion Collisions from SPS to RHIC
    Strange hadron production in heavy ion collisions from SPS to RHIC C. Blume1 and C. Markert2 1Institut f¨ur Kernphysik, Johann Wolfgang Goethe-Universit¨at Frankfurt, Frankfurt, Germany. 2University of Texas at Austin, Austin, Texas 78712, USA. October 22, 2018 Abstract Strange particles have been a very important observable in the search for a deconfined state of strongly interacting matter, the quark-gluon plasma (QGP), which is expected to be formed in ultra-relativistic heavy ion collisions. We review the main experimental observations made at the Super Proton Synchrotron (SPS) at CERN, Geneva, and at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). The large amount of recently collected data allows for a comprehensive study of strangeness production as a function of energy and system size. We review results on yields, transverse mass and rapidity spectra, as well as elliptic flow. The measurements are interpreted in the context of various theoretical concepts and their implications are discussed. Of particular interest is the question whether strange particles are in any way sensitive to a partonic phase. Finally, a compilation of experimental data is provided. Contents 1 Introduction 3 1.1 Strangeness enhancement as QGP signal . ......... 4 2 Theoretical aspects 5 arXiv:1105.2798v2 [nucl-ex] 19 Aug 2011 2.1 Recentdevelopments ................................ ..... 5 2.2 Transportmodels ................................... .... 6 2.3 Statisticalmodels................................... .... 9 3 Experimental overview 12 3.1 Basicobservations .................................. .... 12 3.2 Experimentaltechniques . .. .. .. ...... 13 3.2.1 Chargedkaons .................................... 14 0 3.2.2 Hyperons and KS ................................... 15 3.2.3 Corrections ...................................... 17 1 4 Energy dependence 18 4.1 Strangeness enhancement at different energies .
    [Show full text]
  • Strange Quarks in Nuclei
    -'i-'-.- •//(:•', BROOKHAVEN NATIONAL LABORATORY BNL--46322 June 1991 DE91 015833 STRANGE QUARKS IN NUCLEI Carl B. Dover Physics Department Brookhaven National Laboratory Upton, New York 11973 ABSTRACT We survey the field of strange particle nuclear physics, starting with the spectroscopy of strangeness S = — 1 A hypernuclei, proceeding to an inter- pretation of recent data on 5 = —2 AA hypernuclear production and decay, and finishing with some speculations on the production of multi-strange nuclear composites (hypernuclei or "strangelets") in relativistic heavy ion collisions. Invited talk presented at the Intersections between Particle and Nuclear Physics Tucson, Arizona May 24-29, 1991 This manuscript has been authored under contract number DE-AC02-76CII00016 with the U.S. Depart- ment of Energy. Accordingly, the U.S. Government retains a non-exclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes. DBTRBUTION OF TH,S OOCUMBlf » STRANGE QUARKS IN NUCLEI Carl B. DOVER Brookhaven National Laboratory, Upton, New York 11973, USA ABSTRACT We survey the field of strange particle nuclear physics, starting with the spec- troscopy of strangeness 5 = — 1 A hypernuclei, proceeding to an interpretation of recent data on S = — 2 A A hypernuclear production and decay, and finishing with some speculations on the production of multi-strange nuclear composites (hypernuclei or "strangelets") in relativistic heavy ion collisions. 1. INTRODUCTION In this talk, we explore the strangeness (S) degree of freedom in nuclei. We start with a discussion of S = —1 hypernuclei, which consist of a single hy- peron (A or S) embedded in the nuclear medium.
    [Show full text]
  • Study of Strange Particle Production in Pp Collisions with the ALICE Detector Hélène Ricaud, Alexander Kalweit, Antonin Maire
    Study of strange particle production in pp collisions with the ALICE detector Hélène Ricaud, Alexander Kalweit, Antonin Maire To cite this version: Hélène Ricaud, Alexander Kalweit, Antonin Maire. Study of strange particle production in pp colli- sions with the ALICE detector. Journal of Physics G: Nuclear and Particle Physics, IOP Publishing, 2010, 37 (9), pp.94049. 10.1088/0954-3899/37/9/094049. hal-00600856 HAL Id: hal-00600856 https://hal.archives-ouvertes.fr/hal-00600856 Submitted on 16 Jun 2011 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Study of strange particle production in pp collisions with the ALICE detector H´el`ene Ricaud1, Alexander Kalweit1 and Antonin Maire2 (for the ALICE Collaboration) 1Technical University of Darmstadt, Institut fuer Kernphysik, Schlossgartenstrasse 9, D-64289 Darmstadt, Germany 2Institut Pluridisciplinaire Hubert Curien, 23 rue du Loess, F-67037 Strasbourg, France E-mail: [email protected] Abstract. ALICE is well suited for strange particles production studies since it has very good reconstruction capabilities in the low transverse momentum (pt)regionand it also allows to extend the identification up to quite high pt. Charged strange mesons (K+,K−,) are reconstructed via energy loss measurements whereas neutral strange 0 mesons (Ks ) and strange hyperons (Λ, Ξ, Ω) are identified via vertex reconstruction.
    [Show full text]
  • NEUTRAL KAON and LAMBDA PRODUCTION in ELECTRON-POSITRON ANNIHILATION at 29 Gev and the Z BOSON RESONANCE*
    SLAC-374 UC-414 w NEUTRAL KAON AND LAMBDA PRODUCTION IN ELECTRON-POSITRON ANNIHILATION AT 29 GeV AND THE Z BOSON RESONANCE* Carrie Sue Fordham Stanford Linear Accelerator Center Stanford University Stanford, California 94309 October 1990 Prepared for the Department of Energy under contract number DE-AC03-76SF00515 Printed in the United States of America. Available from the National Techni- cal Information Service, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, Virginia 22161. * Ph. D. thesis ii Abstract The production of Ii” and A in the hadronization of @j events from e+e- collisions at 29 GeV and the 2’ resonance is studied using the Mark II detector as upgraded for running at the Stanford Linear Collider (SLC). Hadronization processes cannot presently be calculated with Quantum Chromodynamics; instead, hadronization models must be used in comparisons with data. In these models, hadronization occurs at local energy scales of a few GeV, a level at which small differences in quark and diquark mass significantly affect the production of particles such as K” and A, the lightest neutral meson and baryon containing strange quarks. Their production and behavior in hadronic events is a test for the accuracy of our understanding of hadronization. Two-charged-particle decays of the K” and A are isolated within the hadronic event sample. The resulting distributions of I<’ and A are corrected for inefficiencies and generalized to include all K” and A. The number of K” per hadronic event is found to be 1.26f0.04f0.14 at 29 GeV and 1.54f0.21 f0.18 at the 2’ resonance.
    [Show full text]