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601.
R. Albrecht T. C. Awes C. Baktash P. Beckmann F. Berger R. Bock G. Classon L. Dragon R. L. Ferguson A. Franz S. Garpman R. Glasow H. A. Gustafsson H. H. Gutbrod K. H. Kampert B. W. Kolb P. Pristiansson I. Y. Lee H. L?hner I. Lund F. E. Obenshain A. Oskarsson I. Ottrlund T. Peitzmann S. Persson F. Plasil A. M. Poskanzer M. Purschke H. G. Ritter R. Santo H. R. Schmidt T. Siemiarczuk S. P. Sorensen E. Stenlung G. R. Young WA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1988,38(1):97-103
Transverse momentum (p T) distributions fo inclusive photons and neutral pions at midrapidity are measured with a lead glass calorimeter in 60 and are measured with a lead glass calorimeter in 60 and 200A·Gev16O+nucleus and and proton+nucleus reactions. Inclusive photon distributions are compared for central and peripheral reactions. The degree of centrality is determined either from the charged particle multiplicity or from the remaining projectile energy in the forward direction. Deviations from a nucleus+nucleus interaction model based upon linear extrapolation from p+p reactions are observed in central16O+Au data. The variation of theaverage transverse momentum is investigated as function of centrality. The target-mass and energy dependence of π0 p T distributions are presented. For16O+Au a change of slope in these distributions is observed atp t ≈0.8 GeV/c compatible with hydrodynamic expansion models. 相似文献
602.
SINDRUM Collaboration W. Bertl R. Eichler L. Felawka H. K. Walter
G. Bowden
S. Egli R. Engfer Ch. Grab E. A. Hermes D. Herter P. Heusi N. Kraus R. J. Powers H. S. Pruys A. v.d. SchaafJ. J. Domingo
J. Jansen N. Lordong J. MergaertJ. Martino
《Physics letters. [Part B]》1984,140(5-6):299-303A search for the decay μ+→e+e+e−, in which no candidate was found, yields a new upper limit for the branching ratio Rμ→3e<1.6×10−10 (90% confidence). A total of 16
decays were observed, in agreement both in number and momentum distribution with V - A theory. 相似文献
603.
W. Bell K. Braune G. Claesson D. Drijard M. A. Faessler H. G. Fischer H. Frehse R. W. Frey S. Garpman W. Geist C. Gruhn P. Hanke M. Heiden W. Herr P. G. Innocenti T. J. Ketel E. E. Kluge I. Lund G. Mornacchi T. Nakada I. Otterlund B. Povh A. Putzer B. Rensch E. Stenlund T. J. M. Symons R. Szwed O. Ullaland M. Wunsch CERN-Heidelberg-Lund Collaboration 《Zeitschrift fur Physik C Particles and Fields》1984,22(2):109-118
Two-particle rapidity correlations have been studied for αα, αp, andp p interactions at the CERN ISR using the Split-Field Magnet (SFM) detector. In order to isolate the true two-particle correlations, the analysis was performed at fixed charged multiplicity. In the framework of a simple cluster model, it is found that cluster widths as well as cluster multiplicities are the same for αα, αp, andp p interactions, and both decrease with increasing charged multiplicity. 相似文献
604.
A tagging method to suppress the π± background in Σ-hypernuclear spectroscopy is examined. The method, which is based on Monte Carlo simulations, investigates the capabilities of Σ to form a hyperon-nucleus bound system. The hypernuclear system can be found either in the ground state or in low-lying state, as well as in a resonance state. The tracking capabilities of the FINUDA spectrometer to detect Σ-hypernuclei are used. Σ-hypernuclei are produced by stopped K?,s. 相似文献
605.
The large hadron collider (LHC) under construction at CERN will deliver ion beams up to centre of mass energies of the order
of 5.5 TeV per nucleon, in case of lead. If compared to the available facilities for the study of nucleus-nucleus collisions
(SpS and RHIC), this represents a huge step forward in terms of both volume and energy density that can be attained in nuclear
interactions. ALICE (a large ion collider experiment) is the only detector specifically designed for the physics of nuclear
collisions at LHC, even though it can also study high cross-section processes occurring in proton-proton collisions. The main
goal of the experiment is to observe and study the phase transition from hadronic matter to deconfined partonic matter (quark
gluon plasma —QGP). ALICE is conceived as a general-purpose detector and will address most of the phenomena related to the
QGP formation at LHC energies: for this purpose, a large fraction of the hadrons, leptons and photons produced in each interaction
will be measured and identified. 相似文献
606.
The OPAL Collaboration G. Abbiendi et al. 《The European Physical Journal C - Particles and Fields》2003,27(4):467-481
Charged particle momentum distributions are studied in the reaction hadrons, using data collected with the OPAL detector at centre-of-mass energies from 192 GeV to 209 GeV. The data correspond
to an average centre-of-mass energy of 201.7 GeV and a total integrated luminosity of 433 pb-1. The measured distributions and derived quantities, in combination with corresponding results obtained at lower centre-of-mass
energies, are compared to QCD predictions in various theoretical approaches to study the energy dependence of the strong interaction
and to test QCD as the theory describing it. In general, a good agreement is found between the measurements and the corresponding
QCD predictions.
Received: 17 July 2002 / Published online: 3 March 2003 相似文献
607.
DELPHI data collected at centre-of-mass energies up to 208 GeV have been analysed to search for charginos, neutralinos and sfermions in the framework of the Minimal Supersymmetric Standard Model (MSSM) with R-parity conservation. No evidence for a signal was found in any of the channels. The results of each search were used to derive limits on production cross-sections and particle masses. In addition, the combined result of all searches excludes regions in the parameter space of the constrained MSSM, leading to limits on the mass of the Lightest Supersymmetric Particle and other supersymmetric particles.Received: 22 February 2003, Revised: 24 July 2003, Published online: 12 November 2003 相似文献
608.
609.
K. Schlösser I. Berkes E. Hagn P. Herzog T. Niinikoski H. Postma C. Richard-Serre J. Rikovska N. J. Stone L. Vanneste E. Zech the ISOLDE Collaboration NICOLE ISOLDE Collaboration 《Hyperfine Interactions》1988,43(1-4):139-149
A facility for Nuclear Implantation into Cold On-Line Equipment (NICOLE) is being installed at the new on-line isotope separator
ISOLDE 3 at CERN. The first on-line run was in the beginning of July 1988. The low temperature equipment has been successfully
tested and first off-line experiments on various isotopes have been performed. NMR/ON has been done on vaious isotopes (Co,
Xe, Pt, Au) in iron host. First experience with the top-loading dilution refrigertor (Oxford Instruments Limited) shows that
it performs very well. The cooling power is 400 μW at 100 mK and 34 μW at 25 mK. The base temperature can be kept continuously
well below 5 mK. NMR/ON can be performed at temperatures below 5.5 mK. The base temperature on-line is expected to be lower
then 6 mK. The sample can be cooled down from room temperature to 10 mK within two hours, to 6 mK within 3 hours which is
not only important for off-line but also for on-line experiments when samples have to be changed to remove long lived daughter
activity. The latest results will be reported. 相似文献
610.
M. J. G. Borge D. G. Burke F. Calaprice O. C. Jonsson G. Løvhøiden R. A. Naumann K. Nybø G. Nyman H. L. Ravn T. F. Thorsteinsen The ISOLDE Collaboration CERN Geneva Switzerland 《Zeitschrift für Physik A Hadrons and Nuclei》1986,325(4):429-434
Neutron-rich isotopes of radon, produced by spallation reactions in a ThC2 target and selected chemically, were mass-separated and used as samples for radiation counting experiments. Assignments of the activities to radon isotopes were confirmed by genetic relationships to the previously known francium daughters. The halflife for the new isotope227Rn is 23±1 s and that for226Rn is 7.4±0.1 min. X-rays,γ-rays, and conversion electrons from the223Rn activity were measured. The decay patterns ofK X-rays and known gamma transitions in the223Fr daughter yield a halflife of 23.2± 0.4 min for223Rn, in contrast to the value of 43± 5 min reported earlier. Energies, intensities, and likely multipolarities for the most prominent gamma transitions in the223Rn→223Fr decay are presented. 相似文献