共查询到20条相似文献,搜索用时 46 毫秒
1.
From the experimental matrix (the number of events with a given number Ng of particles with velocity 0.3c<v<0.7c, and ns, the number of shower particles (v > 0.7c) in a pseudo-rapidity interval Δηi) obtained from the Heidelberg-Igel hadron-nucleus experiment at CERN, we extract the shower particle multiplicity distributions as a function of ν, the number of nucleons that interacted with the projectile. We use a theoretically justified statistical correlation between ν and Ng (recoil protons) and the assumption that the correlation between ns and Ng is given merely through ν. The data used are for incoming energies 50 and 150 GeV with a proton or pion as the projectile and Cu or Pb as the target. We find that the shower particle multiplicity distributions are of a Poissonian character in each η bin and for each value of ν. The average multiplicities are approximately the same for the two targets and for the different projectile, possibly with a small excess for the pion projectile.The results are compared to a rather general theoretical model of the soft interaction type. The predictions from this model for the shower particle pseudorapidity distributions are very close to the derived values. 相似文献
2.
A.T. Abrosimov G. Bellini L.P. Chernenko M. Di Corato G.I. Drondina P.L. Frabetti Yu.I. Ivanshin P. Laurikainen L.K. Litkin V.P. Lobanova E. Meroni S. Michelletti V.A. Moiseenko V.I. Nikanorov S. Otwinowski Z. Otwinowski F. Palombo M. Pernicka O.A. Zaimidoroga 《Nuclear Physics B》1979,158(1):11-28
Multiparticle production in π?-nucleus interactions at 40 GeV/c (Fifth Joint CERN-Serpukhov Experiment) has been studied using a spark-chamber technique at the Serpukhov accelerator. The mean multiplicities, the pseudorapidity distributions and the dispersion of the multiplicity distributions of charged particles produced on C, Al, Cu and Pb targets are presented. The data have been analysed, both subtracting and including secondary protons with p < 1 GeV/c. In the region of pseudorapidity η > 3.4 the average multiplicity is nearly independent of the size () of the target nucleus, while it increases for η < 3.4. In the forward direction (η > 4) the mean multiplicity on nuclei is smaller than the mean multiplicity on hydrogen. The dependence upon in the target fragmentation region is stronger when the emitted protons are included in the pseudorapidity distributions of the secondary particles. The dispersion of the multiplicity distributions for the different nuclear targets versus the mean multiplicity shows the same slope as found by the world statistics on hydrogen and by other experiments on nuclei at different energies. The results are compared with the predictions of the coherent tube model and with the soft hadron-nucleus collision model. 相似文献
3.
M.A. Faessler U. Lynen J. Niewisch B. Pietrzyk B. Povh H. Schröder P.C. Gugelot T. Siemiarczuk I.P. Zielinski 《Nuclear Physics B》1979,157(1):1-22
The experiment studies charged particle production for π?, K?, and interactions on nuclei at 20 and 37 GeV/c at the CERN SPS. A non-magnetic detector, consisting of CsI(Tl) scintillation and lucite ?erenkov counters, distinguishes between fast particles, mainly pions, and slow particles, mainly nucleons, with a cut at velocity β ≈ 0.7. Angular distributions, multiplicity distributions and correlations of slow and fast particles were analysed. It is shown that the measurement of the correlations can provide a critical test for different theoretical models of the hadron-nucleus interaction. At the energies studied so far a systematic deviation from KNO scaling is observed. This gives further support to the “standard picture” of the hadron-nucleus interaction and it contrasts with predictions of the coherent-tube model. The regularity observed for the angular distribution of fast secondaries as a function of the number of slow particles can only be explained by combining features predicted by different models. 相似文献
4.
The dynamic properties of an n-component phonon system in d dimensions, which serves as a model for a structural phase transition of second order, are investigated. The symmetry group of the hamiltonian is the group of orthogonal transformations (n). For n ≥ 2 a continuous symmetry is broken for T<Tc, where Tc is the transition temperature. We derive the hydrodynamic equations for the generators of this group, the angular-momentum variables. Besides the usual hydrodynamics of a phonon system, there are additional independent diffusive modes for T > Tc. In the ordered phase we find 2 (n ? 1) propagating modes with linear dispersion and quadratic damping. Formally the hydrodynamics is similar in the isotropic Heisenberg ferromagnet (n = 2) or the isotropic antiferromagnet (n ≥ 3). The relaxing modes for T < Tc require special care. We study the critical dynamics by means of the dynamical scaling hypothesis and by a mode-coupling calculation, both of which give the critical dynamical exponent . The results are compared with the 1/n expansion. It is shown that for large n there is a non-asymptotic region characterized by an effective exponent , where φ is the crossover exponent for a uniaxial perturbation, and ν the critical exponent of the correlation length. 相似文献
5.
B. Alper H. Bøggild P. Booth L.J. Carroll G. von Dardel G. Damgaard B. Duff J.N. Jackson G. Jarlskog L. Jönsson A. Klovning L. Leistam E. Lillethun S. Olgaard-Nielsen M. Prentice J.M. Weiss 《Nuclear Physics B》1975,87(1):19-40
Results are given on the inclusive production of charged pions, kaons and nucleons in high-energy proton-proton collisions in the centre-of-mass rapidity range |ycm| < 1 and for transverse momenta up to 4.8 GeV/c. The dependence of the composition of produced particles on ycm, the total energy , and transverse momentum pT is discussed. 相似文献
6.
7.
The πNN vertex function is determined from for pn → np and at 8 GeV/c in the interval 0 < ? t < 0.1 GeV2. A “regularor mass” of 3.5mπ=488 MeV is found, corresponding to an “extension” of 0.40 fm of the πNN vertex. The resulting OPE potential is discussed. 相似文献
8.
K.H. Fischer 《Solid State Communications》1983,46(4):309-311
The Glauber dynamics of an Ising spin glass with infinite-range interactions and additional static field, h, is investigated near the freezing temperature, Tf. We obtain critical slowing down at and below the de Almeida-Thouless instability line, hc(T), to order (1?T/Tf)3 with algebraic decay of the spin correlations ~t?ν, where at Tf and for T<Tf. 相似文献
9.
J.G. Rushbrooke R.E. Ansorge C.P. Bust J.R. Carter W.W. Neale C. Moore R. Raja L. Voyvodic R.J. Walker W. Morris B.Y. Oh D.L. Parker G.A. Smith J. Whitmore 《Physics letters. [Part B]》1975,59(3):303-307
New 100 GeV/cp data are used to find moments of the difference between the p and pp topological cross sections. The mean multiplicity for annihilations at 100 GeV/c is estimated to be 9.06 ± 0.56, and the value of the quantity 〈n〉/D to be 2.75 ± 0.33. It is shown that appears at 100 GeV/c to have acquired an asymptotic form, Rn = s?αβn, with α and β constant. 相似文献
10.
R. K. Shivpuri D. Grewal V. K. Verma 《Zeitschrift fur Physik C Particles and Fields》1993,58(3):419-422
We discuss here the nuclear effects in multiparticle production processes in 800 GeV proton-emulsion nuclei interactions. The multiplicity of medium energy particles (N g ) was used as a measure of the average number of projectile collisions (<v(N g )>). To study nuclear effects, we determined <v(N g )> and ratio of normalized rapidity density of all produced charged particles in hadron-nucleus to hadron-hadron interaction,R(N η ). It was found that the average multiplicity of shower particles increases with <v(N g )>. From theR(N η ) distribution, we find; a strong maxima in the target fragmentation region, a plateau in the central region and depletion of particle density in the projectile fragmentation region. 相似文献
11.
W.C. Carithers T. Modis D.R. Nygren T.P. Pun E.L. Schwartz H. Sticker J.H. Christenson 《Nuclear Physics B》1977,118(5):333-338
We have measured the transmission regeneration amplitude for carbon. The invariant amplitude varies from 5.909 ± 0.066 mb at 4.5 GeV/c to 3.933 ± 0.152 mb at 9.5 GeV/c. The results agree with optical model calculations using measured kaon-nucleon total cross sections. The data also provide a value for the ω trajectory intercept αω(0) = 0.42 ± 0.04. 相似文献
12.
B. Alper H. Bℷgild P. Booth F. Bulos L.J. Carroll G. von Dardel G. Damgaard B. Duff F. Heymann J.N. Jackson G. Jarlskog L. Jonsson A. Klovning L. Leistam E. Lillethun G. Lynch G. Manning M. Prentice J.M. Weiss 《Physics letters. [Part B]》1973,46(2):265-268
Measurements have been performed on production of particles with mass 1.5 GeV/c2 and charge for θlab = 62.5° and . At pT = 0.7 GeV/c the relative rate of production of antideuterons to π? is (5 ± 1) × 10?5. The deuteron to antideuteron ratio is 3.7 ± 1.2. No new stable particle has been amongst 0.7 × 108 charged particles entering our detector. 相似文献
13.
T. Åkesson M.G. Albrow S. Almehed E. Anassontzis R. Batley O. Benary H. Bøggild O. Botner H. Breuker H. Brody V. Burkert B. Callen R. Carosi A.A. Carter J.R. Carter P.C. Cecil V. Chernyatin W.A. Zajc 《Physics letters. [Part B]》1985,158(3):282-288
We have measured the production of direct photons, π0's, and η's in p and pp collisions at √s=53 GeV in the range 2≈pT≈6 GeV/c for the central rapidity region |y| 0.4. No statistically significant difference between pp? and pp interactions is observed. 相似文献
14.
A. Berglund T. Buran P.J. Carlson C.J.S. Damerell I. Endo A.R. Gillman V. Gracco R.J. Homer M.J. Hotchkiss A. Lundby M. Macri B.N. Ratcliff A. Santroni T. Tso F. Wickens J.A. Wilson 《Nuclear Physics B》1980,176(2):346-354
The differential cross sections for K?p and p elastic scattering have been measured over the range of four-momentum transfer squared 0.18<?t<3.3 (GeV/c)2. The K?p data decrease smoothly as a function of ?t, whereas, the data shows a break at ?t = 0.6 (GeV/c)2 followed by a fast drop to ?t ? 1.6 (GeV/c)2 where the differential cross section levels off and stays constant out to ?t = 3 (GeV/c)2. 相似文献
15.
J.G. Lee A. Harckham M. Letheren W. Beusch F. Bourgeois E. Polgár D. Websdale K. Freudenreich R. Frosch F.X. Gentit P. Mühlemann 《Nuclear Physics B》1973,52(1):292-300
The differential cross section for the charge exchange has been measured with high statistics at 7.76 GeV/c and at 5.0 GeV/c. The 7.76 GeV/c data show a very narrow [Δt ? 0.01 (GeV/c)2] forward peak superposed on a slow exponential fall-off. 相似文献
16.
Edward P. Osipov 《Reports on Mathematical Physics》1984,20(1):111-116
The ?dν(λ):expλ?:n (without counterterms) quantum field theory is considered. Here ν(·) is a finite positive measure.Let n ? 3, or n = 2 and supp. Under these conditions the theory ?dν(λ):expλ?:n (without counterterms)converges to the free-field theory when the cut- offs are removed. 相似文献
17.
R. Freud 《Solid State Communications》1973,13(1):121-123
It is shown that for tin, indium and lead samples of sufficiently high purity, sufficiently large diameter (2–3mm), and sufficiently close to the critical temperature (ΔT<0.15K), there exists a common value close to (0.64?R(ic)/Rn ? 0.69) of the resistance jump at the transition from the superconducting to the intermediate state. 相似文献
18.
Johann M. Heuser 《Acta Physica Hungarica A》2002,15(3-4):291-301
First results from measurements of Au?Au collisions at $\sqrt {s_{NN} } = 130$ GeV, performed with the PHENIX experiment during the initial physics run of Brookhaven National Laboratory’s Relativistic Heavy Ion Collider in summer 2000, are summarized. Global characterization of the collisions was obtained from charged-particle multiplicity and transverse energy densities. At mid-rapidity, dN ch /dν and dE T /dν rise steadily with the event centrality, while the ratio <E T >/<N ch > remains constant. Transverse momentum spectra of charged particles up to 5 GeV/c yield a suppression of high-momentum particles in the most central events when compared to a simple scaling of binary nucleon-nucleon collisions. The scaling matches with peripheral collisions. Transverse momentum spectra of identified neutral pions from 1 to 4 GeV/c in peripheral collisions show consistency with point-like scaling with the average number of binary collisions. Yields in central collisions are significantly suppressed. Transverse momentum spectra of identified charged hadrons up to 3.5 GeV/c were measured in minimum bias events. The mass and centrality dependencies of inverse slope parameters and mean transverse momenta were determined. Inclusive spectra of electrons were measured for momenta from a few hundred MeV/c to 4 GeV/c. Inclusive photon spectra from a few hundred MeV/c to 3 GeV/c were obtained from conversion pair measurements. 相似文献
19.
J. Bartke M. Deutschmann H.G. Kirk P. Sixel L. Becker H. Vogt R. Hartmann H. Plothow D. Kocher D.R.O. Morrison P. Porth K. Eskreys K. Olkiewicz K. Doroba T. Hofmokl 《Nuclear Physics B》1977,120(1):1-13
Interactions in which the baryon is emitted forwards in the c.m.s. are studied in 8 and 16 GeV/cπ+p collisions. These interactions are interpreted as representing baryon exchange. The properties of such off-shell N annihilation events are studied. It is found that the multiplicity distribution of the multi-pion system as a function of the effective mass for events with |upp| < 1 GeV2 is the same as for real annihilations. 相似文献