共查询到20条相似文献,搜索用时 431 毫秒
1.
The interactions of 4.1AGeV/c
22Ne and 4.5AGeV/c
32S nuclei with emulsion have been studied and the dependence of the average multiplicities of the emitted secondary charged
particles and the interacting projectile nucleons on the impact parameters have been investigated. The behavior of the Koba-Neilsen-Olesen
(KNO) scaling formula of the multiplicity distributions produced due to the interactions of22Ne and32S at the energies mentioned above is satisfied by all target protons. The multiplicity distributions of the emitted4He fragments and the fragmentation cross-section relative to the inelastic cross-section have been investigated and give a4He-fragments yield which is always ten times greater than the yield of any other fragments. The dependence of the normalized
mean multiplicity and the reduced multiplicity on the mass of the projectile and target nucleus can be described by a power
law. 相似文献
2.
S. Vokál A. Vokálová A. Kravčáková S. Lehocká G. I. Orlova 《Physics of Atomic Nuclei》2008,71(8):1395-1402
The angular structures of particles produced in 208Pb-induced collisions with Ag(Br) nuclei in an emulsion detector at 158 A GeV/c have been investigated. Nonstatistical ringlike substructures in the azimuthal plane of the collision have been found and
their parameters have been determined. An indication of the formation of ringlike substructures from two symmetrical emission
cones, one in the forward and the other in the backward direction in the center-of-mass system, has been obtained. The ringlike
substructures’ parameters have been determined. The experimental results are in an agreement with I.M. Dremin’s idea that
the mechanism of the ringlike substructures’ formation in nuclear collisions is similar to that of Cherenkov electromagnetic
radiation.
The text was submitted by the authors in English. 相似文献
3.
《The European Physical Journal C - Particles and Fields》2008,53(2):177-204
A measurement of the double-differential π± production cross-section in proton–carbon, proton–copper and proton–tin collisions in the range of pion momentum 100 MeV/c≤p<800 MeV/c and angle 0.35 rad≤θ<2.15 rad is presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS.
The pions were produced by proton beams in a momentum range from 3 GeV/c to 12 GeV/c hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced
particles was done using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. An elaborate
system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential
cross-sections d2σ/dpdθ at four incident proton beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c).
PACS 13.75.Cs; 13.85.Ni 相似文献
4.
M. Deutschmann G. Ransone P. Sixel H. Böttcher R. Nahnhauer Y. Goldschmidt-Clermont G. Kellner D.R.O. Morrison F.A. Triantis J. Figiel K. Sliwa K.W.J. Barnham P. Newham J. Wells P.R.S. Wright M. Zomorrodian F. Mandl A. Jacholkowska 《Nuclear Physics B》1979,155(2):307-319
Differential cross sections of single particles and multiparticle systems produced in K?p interactions at 110 GeV/c are presented. At large values of transverse momentum (p⊥) we find the multiparticle cross section to be an order of magnitude larger than that for single particles. This and other features of our data are consistent with results obtained at 200 GeV/c, that have been interpreted as evidence of a new dynamical mechanism in hadron-hadron interactions. However, similar features are observed in a K?p experiment at 16 GeV/c. 相似文献
5.
《The European Physical Journal C - Particles and Fields》2007,51(4):787-824
A measurement of the double-differential cross-section for the production of charged pions in proton–tantalum collisions emitted
at large angles from the incoming beam direction is presented. The data were taken in 2002 with the HARP detector in the T9
beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 GeV/c to 12 GeV/c hitting a tantalum target with a thickness of 5% of a nuclear interaction length. The angular and momentum range covered
by the experiment (100 MeV/c ≤p< 800 MeV/c and 0.35 rad ≤θ< 2.15 rad) is of particular importance for the design of a neutrino factory. The produced particles were
detected using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. Track recognition,
momentum determination and particle identification were all performed based on the measurements made with the TPC. An elaborate
system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential
cross-sections d2σ/dpdθ at four incident proton beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c). In addition, the pion yields within the acceptance of typical neutrino factory designs are shown as a function of beam
momentum. The measurement of these yields within a single experiment eliminates most systematic errors in the comparison between
rates at different beam momenta and between positive and negative pion production.
PACS 13.75.Cs; 13.85.Ni 相似文献
6.
V. P. Ladygin L. S. Azhgirey S. V. Afanasiev V. V. Arkhipov V. K. Bondarev Yu. T. Borzounov G. Filipov L. B. Golovanov A. Yu. Isupov V. I. Ivanov A. A. Kartamyshev V. A. Kashirin A. N. Khrenov V. I. Kolesnikov V. A. Kuznetsov N. B. Ladygina A. G. Litvinenko S. G. Reznikov P. A. Rukoyatkin A. Yu. Semenov I. A. Semenova G. D. Stoletov A. P. Tzvinev V. N. Zhmyrov L. S. Zolin 《Physics of Atomic Nuclei》2006,69(5):852-859
The angular dependence of the tensor A
yy and vector A
y analyzing powers in the inelastic scattering of deuterons with a momentum of 9.0 GeV/c on hydrogen and carbon has been measured. The range of measurements corresponds to the baryonic resonance excitation with
masses of ∼2.2–2.6 GeV/c
2. The A
yy data, being in good agreement with the previous results, demonstrate an approximate t scaling up to −1.5 (GeV/c)2. The large values of A
y show a significant role of the spin-dependent part of the elementary amplitude of the NN → NN* reaction. The results of the experiment are compared with model predictions of the plane-wave impulse approximation.
The text was submitted by the authors in English. 相似文献
7.
R. Arnaldi K. Banicz K. Borer J. Castor B. Chaurand W. Chen C. Cicalò A. Colla P. Cortese S. Damjanovic A. David A. de Falco A. Devaux L. Ducroux H. En’yo J. Fargeix A. Ferretti M. Floris A. F?rster P. Force N. Guettet A. Guichard H. Gulkanian J. M. Heuser M. Keil L. Kluberg Z. Li C. Louren?o J. Lozano F. Manso P. Martins A. Masoni A. Neves H. Ohnishi C. Oppedisano P. Parracho P. Pillot T. Poghosyan G. Puddu E. Radermacher P. Ramalhete P. Rosinsky E. Scomparin J. Seixas S. Serci R. Shahoyan P. Sonderegger H. J. Specht R. Tieulent G. Usai R. Veenhof H. K. W?hri 《The European Physical Journal C - Particles and Fields》2009,59(3):607-623
The yield of muon pairs in the invariant mass region 1<M<2.5 GeV/c
2 produced in heavy-ion collisions significantly exceeds the sum of the two expected contributions, Drell-Yan dimuons and muon
pairs from the decays of D meson pairs. These sources properly account for the dimuons produced in proton-nucleus collisions.
In this paper, we show that dimuons are also produced in excess in 158 A GeV In-In collisions. We furthermore observe, by tagging the dimuon vertices, that this excess is not due to enhanced D meson
production, but made of prompt muon pairs, as expected from a source of thermal dimuons specific to high-energy nucleus-nucleus collisions. The yield of
this excess increases significantly from peripheral to central collisions, both with respect to the Drell-Yan yield and to
the number of nucleons participating in the collisions. Furthermore, the transverse mass distributions of the excess dimuons
are well described by an exponential function, with inverse slope values around 190 MeV. The values are independent of mass
and significantly lower than those found at masses below 1 GeV/c
2, rising there up to 250 MeV due to radial flow. This suggests the emission source of thermal dimuons above 1 GeV/c
2 to be of largely partonic origin, when radial flow has not yet built up. 相似文献
8.
L. S. Azhgirey S. V. Afanasiev A. Yu. Isupov V. I. Ivanov A. N. Khrenov V. P. Ladygin N. B. Ladygina A. G. Litvinenko V. F. Peresedov N. P. Yudin V. N. Zhmyrov L. S. Zolin 《Physics of Atomic Nuclei》2005,68(6):991-998
Tensor A yy and vector A y analyzing powers in the inelastic scattering of deuterons with a momentum of 5.0 GeV/c on beryllium at an angle of 178 mrad in the vicinity of the excitation of baryonic resonances with masses up to ~ 1.8 GeV/c 2 have been measured. The A yy data are in good agreement with the previous data obtained at 4.5 and 5.5 GeV/c. The results of the experiment are compared with the predictions of the plane-wave impulse approximation and ω meson-exchange models. 相似文献
9.
V. P. Ladygin L. S. Azhgirey S. V. Afanasiev V. V. Arkhipov V. K. Bondarev G. Filipov A. Yu. Isupov V. I. Ivanov A. A. Kartamyshev V. A. Kashirin A. N. Khrenov V. I. Kolesnikov V. A. Kuznetsov N. B. Ladygina A. G. Litvinenko S. G. Reznikov P. A. Rukoyatkin A. Yu. Semenov I. A. Semenova G. D. Stoletov V. N. Zhmyrov L. S. Zolin 《The European Physical Journal A - Hadrons and Nuclei》2000,8(3):409-416
The tensor Ayy and vector Ay analyzing powers in the inelastic scattering of deuterons with a momentum of 4.5 GeV/c on beryllium at an angle of 80 mr in the vicinity of baryonic resonances excitation have been measured. The Ayy data being in good agreement with the previous results obtained at a zero angle demonstrate an approximate t scaling up to - 0.9 (GeV/c)2. The results of the experiment are compared with the predictions of the multiple-scattering and -meson exchange models.
Received: 20 April 2000 / Accepted: 29 May 2000 相似文献
10.
《Physics letters. [Part B]》1988,209(1):127-134
Two-jet mass distributions have been measured as a function of centre-of-mass scattering angle for high-mass jet pairs produced in proton-antiproton collisions at the CERN collider operating at a centre-of-mass energy of 630 GeV. The agreement between QCD expectations and the experimental measurements has been used to place limits on the production cross section of an object X decaying into two jets. In particular we consider the existence of a massive colour octet of vector gauge bosons (axigluons). We exclude axigluons with a width ΛA < 0.4mA and a mass mA in the range 150 < mA < 310 GeV/c2 (95% CL). 相似文献
11.
Andrew M. Adare 《The European Physical Journal C - Particles and Fields》2009,62(1):127-131
Angular correlations involving energetic particles associated with partonic jet fragmentation provide an important opportunity
to study the hot nuclear matter produced in A+A collisions, particularly when compared against a p+p reference. Recent results from di-hadron correlations suggest that jet observables from A+A and p+p differ considerably at low p
T
but approach comparable values as p
T
increases above 7 GeV/c, providing clues on the nature of partonic energy loss and the medium response. The most recent π
0-triggered jet correlation results from the PHENIX experiment are presented, as well as a quantitative study of the jet-peak
widths and shapes. 相似文献
12.
O. V. Selyugin 《The European Physical Journal A - Hadrons and Nuclei》2006,28(1):83-89
The analysing power AN is examined in the range of the Coulomb-hadron interference on the basis of the experimental data from pL = 6 GeV/c up to 200 GeV/c taking account of a phenomenological analysis at pL = 6 GeV/c and a dynamic high-energy spin model. The results are compared with the new RHIC data at pL = 100 GeV/c. The new experimental data obtained at RHIC indicate small contributions of the hadron spin-flip amplitude. 相似文献
13.
P. Astbury J. Gallivan J. Jafar M. Letheren V. Steiner J.A. Wilson W. Beusch M. Borghini D. Websdale L. Fluri K. Freudenreich F.X. Gentit W. Wetzel P. Le Du O. Guisan 《Nuclear Physics B》1975,99(1):30-52
We present measurements for the baryon-exchange reaction π?p→ΛK0 at 5 GeV/c over the range ?u<2(GeV/c)2. The differential cross section is obtained from events produced on a liquid hydrogen target. These data are combined with events produced on a butanol polarized target and the parameters P, A, and R are then determined from an analysis of the decay angular distribution of the forward-going Λ. From our data it is possible to determine the magnitudes and the relative phase of the two invariant amplitudes A′ and B. The consequences for the ratio B/A′ are discussed in detail. 相似文献
14.
Intranuclear cascading mechanism one of the important non-linear effects in high energy nucleusnucleus collisions is investigated. The data on multiplicity (n s ) and pseudorapidity (η) distributions of shower particles produced by32S and16O at 200A GeV,16O at 60A GeV,28Si at 14.5A GeV and He at ≈140A GeV are presented and compared with the string model VENUS, which takes into account the cascade interactions of secondary particles. The effect of the intranuclear collisions on the distributions of <η> versus <n s > is discussed for all the beams. 相似文献
15.
U.U. Abdurakhmanov K.G. Gulamov V.V. Lugovoi V.Sh. Navotny 《Chinese Journal of Physics (Taipei)》2018,56(6):2689-2697
The statistical event-by-event analysis of inelastic interactions of 16O and 32S nuclei in emulsion at 60 A?GeV/c and 200 A?GeV/c reveals the existence of groups of high multiplicity events belonging to very central nuclear interactions with Gaussian pseudorapidity distributions for produced particles as suggested by the original hydrodynamic-tube model. Characteristics of these events are presented. The experimental observations are interpreted as a result of quark-gluon plasma formation in the course of central nuclear interactions. 相似文献
16.
G. Conforto M.A. Kramer D. Underwood R.M. Mobley A.W. Key R. Prepost D.H. Tompkins M.S. Witherell 《Physics letters. [Part B]》1973,45(2):154-156
The missing mass spectrum in the region of the A?2 has been measured in the reaction π?p→X?p at 6.0 GeV/c in the interval 0.27 <|t|<0.42 (GeV/c)2, with an optical spark chamber system which simultaneously observed the decay X?→ηπ?. A signal of 230 events above background per five MeV interval is observed at the A2 peak, with a signal-to-background ratio of greater than 1:1. A single D-wave Breit-Wigner distribution with a quadratic background gives a good fit to the data, yielding the parameters M0=(1.324±0.003) GeV/c2 and Γ0=(0.104±0.009) GeV/c2. The spectrum is incompatible with a dipole shape. 相似文献
17.
The DELPHI Collaboration J. Abdallah et al. 《The European Physical Journal C - Particles and Fields》2003,26(4):505-525
In some supersymmetric models, the gluino () is predicted to be light and stable. In that case, it would hadronize to form R-hadrons. In these models, the missing energy
signature of the lightest supersymmetric particle is no longer valid, even if R-parity is conserved. Therefore, such a gluino
is not constrained by hadron collider results, which looked for the decay . Data collected by the DELPHI detector in 1994 at 91.2 GeV have been analysed to search for events. No deviation from Standard Model predictions is observed and a gluino mass between 2 and 18 GeV/c2 is excluded at the 95% confidence level in these models. Then, R-hadrons produced in the squark decays were searched for
in the data collected by DELPHI at the centre-of-mass energies of 189 to 208 GeV, corresponding to an overall integrated luminosity
of 609 Pb-1. The observed number of events is in agreement with the Standard Model predictions. Limits at 95% confidence level are derived
on the squark masses from the excluded regions in the plane ()
GeV/c2, and GeV/c2 for purely left squarks.
GeV/c2, and GeV/c2 independent of the mixing angle.
Received: 6 November 2002 / Published online: 15 January 2003 相似文献
18.
R. Vidal S.W. Herb L.M. Lederman H.D. Snyder J.K. Yoh C.N. Brown W.R. Innes R.D. Kephart K. Ueno T. Yamanouchi D.M. Kaplan A.S. Ito H. Jöstlein W. Smith 《Physics letters. [Part B]》1978,77(3):344-346
We have searched for an almost stable, charged particle produced in 400 GeV proton-nucleus collisions. A total of 5 × 1010 light secondary particles were sampled in a secondary beam of 70 GeV/c momentum. If a 4.5 to 6.0 GeV mass particle is produced with a cross section comparable with the production cross section of the upsilon then this experiment places an upper limit on the lifetime of such a particle of about 5 × 10?8 s. 相似文献
19.
G. Coremans-Bertrand J. Sacton A. Breslin S. McMahon A. Montwill D.H. Davis D.N. Tovee F.R. Stannard G. Baroni S. Di Liberto A. Manfredini S. Petrera G. Romano M. Jung N. Kurtz M. Paty T. Pniewski 《Physics letters. [Part B]》1976,65(5):480-482
The associated production of charmed particles by the interactions of 300 GeV/c protons with complex nuclei has been sought using nuclear emulsions. The failure to observe any candidates for this process among some 60,000 interactions investigated implies, provided charmed particles lifetimes are in the range 10?12 to 10?14 s, a cross section for their associated production by the interactions of 300 GeV/c protons with nucleons of less than 1.5 microbarns at a 90% confidence level. 相似文献
20.
H. Braun D. Brick A. Fridman J. -P. Gerber P. Juillot G. Maurer A. Michalon M. -E. Michalon-Mentzer C. Voltolini 《Physics letters. [Part B]》1976,60(5)
Based on 4085
events, X denoting a neutral
N or
system, we present evidence for 5.1 and 3.1 standard deviation enhancements at the X mass of 2.85 and 3.05 GeV/c2, respectively. The lower mass bump has a width of Λ 39 GeV/c2 while the 3.05 GeV/c2 is seen as a one bin accumulation (20 GeV/c2 width). The relevance of these peaks is discussed. 相似文献