We propose to expose two stacks of nuclear emulsion to the 200 and 500 GeV/c protons. In these stacks, the following properties are examined: (1) energy dependence of total, elastic, and inelastic cross sections, (2) contribution of diffraction dissociation, (3) energy dependence of mean multiplicity, (4) character of multiplicity distribution, (5) behaviors of backwards particles for which momenta and masses are determined

/INS, Tokyo

Kaneko, S.

Kusumoto, O.

Mikamo, S.

Ozaki, S.

Teranaka, M.

U., /Hiroshima

U., /Osaka City

Watanabe, K.

UNT (University of North Texas) Digital Library

NAL PROPOSAL No. 117 Correspondent: 	 o. Kusumoto Department of Physics Faculty of Science Osaka City University Sugimoto-cho, Sumiyoshi-k Osaka, Japan PHENOMENOLOGICAL STUDY OF 200 and 500 GeV/c PROTON-PROTON COLLISIONS IN EMULSION S. Ozaki, o. Kusumoto, M. Teranaka, K. Watanabe Osaka City University S. Kaneko Hiroshima University S. Mikamo INS Tokyo University February 27, 1971 ----_._------------­February 27, 1971 NAL PROPOSAL Phenomenological Study of 200 and 500 GeV/c proton-proton collisions in Emulsion Names of Experimenters: S.Ozaki, O.Kusumoto, M.Teranaka and K.Watanabe - Osaka City Univ. S.Kaneko - Hiroshima Univ. S.Mikamo - INS Tokyo Univ. Name of Correspondent: O.Kusumoto, Department of Physics, Faculty of Science, Osaka City University, Sugimoto-cho, Sumiyoshi-ku, Osaka, Japan. Abstract We propose to expose two stacks of nuclear emulsion to the 200 and 500 GeV/c protons. In these stacks, the following properties are examined. 1) energy dependence of total, elastic and inelastic cross sections, 2) contribution of diffraction dissociation, 3) energy dependence of mean multiplicity, 4) character of multiplicity distri­bution, 5) behaviors of backward particles for which momenta and masses are determined. PHYSICS JUSTIFICATION The following properties of the proton-proton collisions at momenta of 200 and 500 GeV/c are examined: 1) elastic and inelastic cross sections, 2) contribution of diffraction dissociation, 3) energy dependence of mean multiplicity, 4) character of multiplicity distribution, 5) behaviors of backward particles for which momenta and masses are determi ned. What tendency is observed for the cross sections at very high energy, l ~he~her they dec~dase.)that 1S, own to zero or approach a constant or increase like a logarithmic way with energy, is one of the basic problems l ). Though the emulsion experiment is somewhat weak to compete with the counter experiment about this problem, the cross sections and their energy dependences are at first checked through the selected events. According to 1T-·nucleus experiments in emulsion2), the cross section per nucleon for diffraction dissociation increases roughly proportional to p~/2 up to 60 GeV/c where Po is the incident momentum and is amount­ing to ~ 1 mb at 60 GeV/c. It is pointed out by Feynman3) that at high energy limit this process should be 10 %of the elastic one. The second purpose of the present proposal is to derive the cross sections for this process of the proton at 200 and 500 GeV/c. The en~gy depend­ence of mean multiplicity of charged particles, <n':to>, is also a basic problem to consider the structure of multiparticle process3,4). The Ii· recent results of accelerator experiments5) show that < nt> seems to have a power dependence with energy rather than logarithmic way. It is our thi rd purpose to see thi s energy dependence of <n:l') for proton­proton collisions. The fourth aim is to examine whether the prong­number distributions at energies of hundreds GeV are pure Poissonian or not1). This gives us the information whether there exists any correlation between particles at their production stage. In recent cosmic ray experiment6). it is reported that there seems to be some production correlation between secondaries7). The final ;s the main purpose of the present proposal. About 10 %of particles emitted backward in the proton-proton eMS should be determined their momenta by the single or relative scattering measurements. By a10ng-the­track scanning of '" 10 km in emulsion, ",3000 protpn-proton collisions (collisions with free and quasi-free protons) should be detected when the cross section for PP is 40 mb (corresponding mean free path - 3.1 m). Among the visible prongs associated with these collisions, about 1500 prongs should be determined their momenta (these prongs have track lengths per plate more than 5 mm). The maximum momentum of a recoil proton is estimated to be ...., 1.4 GeV/c under the assumptions of P*» Mp and p*.» P..L where p* and PJ. are momentum and transverse momentum of a ~ )proton and Mp the proton mass** • **)Under these assumptions, the momentum of a proton in Lab. system, P, is wri tten as, - 1 .L (1' I.."f"H &)~ 'n2.t'i:I P - ¥-H.t L. I' 1-,...&. • II P comes from p.... • Since PJ.max is -1 GeV/c, we have Pma~ 1.4 GeV/c.max max ii.' Therefore, all of the recoil protons among the 1500 prongs could be identified. Since the situation of P*»M for pions and kaons is ex­pected not to be so different for the case of the recoil proton and the mode value of P~ of pions or kaons is also expected to be relatively smaller than P*, the chance we can identify pions and kaons seems to be more than 50 %. Using these results, we can examine at first the features of angular and momentum distributions for protons, pions and kaons. Second, according to the parton mode1 36r the hypothesis of limiting fragmentation~)the longitudinal momentum distribution in lab. system for special particles, that is, protons, pions or kaons, at fixed P~ approaches a limiting one at very high energy. The tendency to approach a limit seems to be observed at the energies produced by accelerators nowavai1ab1eS). Though much more statistics are needed, at high energy and also highly inelastic limits, we could observe the parton mass9) if the model is correct. It is not clear at present that from where the condition of high energy and highly inelastic is satisfied. In order to proceed the study along this line, we are pre­paring a Helmholtz type pulsic magnet. In the studies aforementioned, the nuclear emulsion is essentially useful, because at the energies few hundred GeV about 10 charged particles are produced by a collision and emitted in a very narrow cone and there­fore a fine spacial resolving power is generally required. References 1) S.J.Chang and T.M.Van, Phys. Rev. letters 25 1586 (1970). 2) E.V.Anzon et a1., Phys.letters 31B 241 (1970). 3) R.P.Feynman, Phys. Rev. Letters 25 1415 (1969). 4) S.J.Chang and T.M.Van, Phys. Rev. Letters 25 1586 (1970). 5) E.V.Anzon et a1., Phys. Letters 31B 237 (1970). 6) L.W.Jones et a1., Phys. Rev. Letters 25 1679 (1970). 7) C.P.Wang, Phys. Rev. 180 1463 (1969). 8) J.Benecke et al., Phys. Rev. 188 2159 (1969). 9) J.D.Bjorken and E.A.Paschos, Phys. Rev. 185 1975 (1969). Experimental Arrangement 1) Beam: Protons of 200 and 500 GeV/c. 2) Intensity: 104 - 105 protons/cm2• We would desire two test exposure of intensities 104 and 105 and then determine the final value. 3) Emulsion: Ilford K-5 pellicle of 600 micron thick and 10 x 20 cm2 , 47 sheets/stack. Beam parallel to the 20 cm side. 4) Alignment: as accurate as possible. Apparatus 1) Emulsion storage facilities protecting from background radiations, high humidity and high temperature. 2) Processing facilities: grid-printing, adhesion of pellicle and backing glass, developing and drying. NAL PROPOSAL 	 No. l17-A Correspondent: 	 O. Kusumoto Department of Physics Faculty of Science Osaka City University Sugimoto-cho, Sumiyoshi-ku Osaka, Japan PHENOMENOLOGICAL STUDY OF 200 and 500 GeV/c PROTON-PROTON COLLISIONS IN EMULSION S. 	Ozaki, o. Kusumoto, M. Teranaka, K. Watanabe Osaka City University S. Kaneko Hiroshima university S. Mikamo INS Tokyo university ADDENDUM NO. 	 1 February 29, 	1972 Proposal File No. -11 7 ___ Master .!......I­DO JRS We wish to propose the exposures of our proposal no. 117 to split into two parts, namely, the one is the exposures described in the proposal, but we use somewhat smaller sizes of stacks, and the other one is the five kinds of sandwich stacks, each having a Be, AI, Ni, Ag or W foil between pellicles. The latter is used to get the total cross section for the proton­nucleus collision on each nucleus and to see what the energy and mass number dependences are. At present, we have not any definite information about the proton-nucleus collision in the energy range more than 100 GeV. Therefore, it is fruitful to obtain the general features on it as much as possible, for example, for the total cross section, diffraction dissociation, and their mass number dependences and so on. The sandwich stacks are suitable and convenient to derive this information efficiently. We use the sandwich stack made up by three pellicles of 5 cm x 5 em, 600 ~ thick and one metal foil of 200 ~ 400 ~ thick and expose vertically to the emulsion plane with a 104 2beam density of ~ 5 x particles/em • This exposure can afford us more than 10 3 events of the desired proton-nucleus 2/ 3collision when the cross section is assumed to be 50 Amillibarns. The scanning rate is about one sandwiched stack per scanner-month. The ordinary stack is composed of 3 dozen pellicles of 7.5 cm x 15 cm, 600 microns thick each, in which we expect the number of the proton-proton collisions to be about 8 x -2­310 under the condition of the exposed density of 104 particles/ 2 cm and of the cross section of pp, 40 mb. The purpose we wish to add to those of the proposal no. 117 is the short-lived particle hunting. Recently Niu found an event which might be a decay of a new particle with a supposed l 'f t' -13,1 e 1me around 10 sec 1n his cosmic ray study. The emulsion has an essential advantage to search such a short-lived particle because of its fine spacial resolving power. If the Lorentz factor of the particle is 100, we can derive the information about the lifetime of that particle down to 10-16 sec. The hunting of any short-lived particle is done by inspecting near the vertex point of the proton or pion hitting to the nucleon or nucleus. This analysis is mutually complementary with Niu's experiment (proposal no. 156). 1According to the recent theoretical works based on the Glauber theory2, if heavy mass resonances with masses up to 2P/R on Regge recurrences where P is the incident proton. momentum and R is the nuclear radius of the target, contributes in the intermediate stage of the collision, that is, in the stage that the impinging proton passes through the nucleus, the total elastic cross section has a strong energy dependence especially in the light nuclei. The emulsion has a value of mean mass number (A), 48.5 and ~2/3, 13.2 where the contribution lof the free hydrogen is excluded. The calculation of Trefilshows that in this case the total elastic cross section (P + A + P + A) has a difference ~ 10% between impinging proton energies -3­100 and 300 GeV. Therefore, we can have a chance to check the contribution of the higher mass resonances. In addition to the proton exposures with energies more than 100 GeV, we wish to propose the exposures of the same kind of an ordinary and the five sandwich stacks for pions with the same energies of protons. The same kind of analysis as the protons is applied and the results are compared with those of protons, for example, target fragmentation, diffraction dissociation, and short-lived particle hunting, and so on. Therefore, we would like to change the subject of our proposal to "Phenomenological Study of Proton and Pion Interactions at Energies More Than 100 GeV Using Emulsion". The proposal includes the studies as: 1. proton or pion - nucleon interactions 2. proton or pion - nucleus interactions 3. short-lived particle hunting and requires the exposures of ordinary and sandwich stacks to each proton or pion beam at least in two different energies more than 100 GeV. We add the following collaborators to the original group: S. Higashi, Osaka City University M. Ohta, Kinki University J. Yokota, Science Education Institute of Osaka Prefecture REFERENCES 1. 	 J. S. Trefi1, Phys. Rev. D3 1615 (1971), other references included therein. 2. 	 J. Glauber, in High Energy Physics and Nuclear Structure, edited by S. Devons (Plenum, New York, 1970). 

Phenomenological study of 200 and 500 GeV/c proton-proton collisions in emulsion

https://digital.library.unt.edu/ark:/67531/metadc889953/m2/1/high_res_d/901690.pdf

Phenomenological study of 200 and 500 GeV/c proton-proton collisions in emulsion

Abstract

Similar works

Full text

Available Versions

UNT (University of North Texas) Digital Library