Results of resonance searches in the Xi(-)pi(-), Xi(-)pi(+), Xi;(+)pi(-), and Xi;(+)pi(+) invariant mass spectra in proton-proton collisions at sqrts=17.2 GeV are presented. Evidence is shown for the ...existence of a narrow Xi(-)pi(-) baryon resonance with mass of 1.862+/-0.002 GeV/c(2) and width below the detector resolution of about 0.018 GeV/c(2). The significance is estimated to be above 4.2sigma. This state is a candidate for the hypothetical exotic Xi(--)(3/2) baryon with S=-2, I=3 / 2, and a quark content of (dsdsū). At the same mass, a peak is observed in the Xi(-)pi(+) spectrum which is a candidate for the Xi(0)(3/2) member of this isospin quartet with a quark content of (dsus-d). The corresponding antibaryon spectra also show enhancements at the same invariant mass.
The STAR Level-3 trigger system Adler, C.; Berger, J.; Demello, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2003, Letnik:
499, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The STAR Level-3 trigger issues a trigger decision upon a complete online reconstruction of Au+Au collisions at relativistic heavy ion collider energies. Central interactions are processed up to a ...rate of
50
s
−1
including a simple analysis of physics observables. The setup of the processor farm and the event reconstruction as well as experiences and the proposed trigger algorithms are described.
The production of charged pions in minimum bias p+C interactions is studied using a sample of 377000 inelastic events obtained with the NA49 detector at the CERN SPS at 158 GeV/c beam momentum. The ...data cover a phase space area ranging from 0 to 1.8 GeV/c in transverse momentum and from -0.1 to 0.5 in Feynman xF. Inclusive invariant cross sections are given on a grid of 270 bins per charge, thus offering for the first time a dense coverage of the projectile hemisphere and of the cross-over region into the target fragmentation zone.
New results on the production of charged pions in p+p interactions are presented. The data come from a sample of 4.8 million inelastic events obtained with the NA49 detector at the CERN SPS at 158 ...GeV/c beam momentum. Pions are identified by energy loss measurement in a large TPC tracking system which covers a major fraction of the production phase space. Inclusive invariant cross sections are given on a grid of nearly 300 bins per charge over intervals from 0 to 2 GeV/c in transverse momentum and from 0 to 0.85 in Feynman x. The results are compared to existing data in overlapping energy ranges.
Results on charged pion and kaon production in central Pb+Pb collisions at 20A and 30A GeV are presented and compared to data at lower and higher energies. Around 30A GeV a rapid change of the energy ...dependence for the yields of pions and kaons as well as for the shape of the transverse mass spectra is observed. The change is compatible with the prediction that the threshold for production of a state of deconfined matter at the early stage of the collisions is located at low CERN Super Proton Synchroton energies.
The STAR level-3 trigger system Lange, J.S; Adler, C; Berger, J ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2000, Letnik:
453, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The STAR level-3 trigger is a MYRINET interconnected ALPHA processor farm, performing online tracking of
N
track≥8000 particles (
N
point≤45 per track) with a design input rate of
R=100
Hz
. A ...large-scale prototype system was tested in 12/99 with laser and cosmic particle events.
Abstract Background One proposed strategy to increase the success of irrigation and debridement with implant retention for the treatment of acute periprosthetic joint infection (PJI) is the use of ...dissolvable antibiotic impregnated calcium sulfate beads to provide a local depot of antibiotics. The purpose of this study was to evaluate the outcome of such an approach. Methods Thirty-two patients with acute hematogenous (18 patients; 1 bilateral) or acute postoperative (14 patients) PJIs who underwent irrigation and debridement with implant retention and addition of antibiotic-impregnated calcium sulfate beads were retrospectively reviewed. PJI followed 27 total knees and 6 total hips. The most common infecting organisms were methicillin-sensitive staphylococcus aureus (13/33) and Streptococcus (9/33). The primary outcome parameter was recurrence of infection according to MSIS criteria. Patients were followed for a minimum of 3 months or until failure. Results At a mean of 12.7 months (range, 3 to 30 months), 16 of the 33 patients failed (48%). Acute hematogenous and acute postoperative PJI had similar failure rates at 47% and 50%, respectively (p=0.88). Seven failures required a two-stage exchange, while 8 patients were treated with chronic antibiotic suppression, being unwilling or unable to undergo further surgical intervention. Conclusion The addition of antibiotic-impregnated calcium sulfate beads does not appear to improve outcomes of irrigation and debridement with implant retention in the setting of acute hematogenous or acute postoperative PJI. Given the short follow-up in this report, this represents a best-case scenario and the overall failure rate may be higher with further follow-up.
Results are presented on event-by-event electric charge fluctuations in central Pb+Pb collisions at 20A,30A,40A,80A, and 158A GeV. The observed fluctuations are close to those expected for a gas of ...pions correlated by global charge conservation only. These fluctuations are considerably larger than those calculated for an ideal gas of deconfined quarks and gluons. The present measurements do not necessarily exclude reduced fluctuations from a quark-gluon plasma because these might be masked by contributions from resonance decays.
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