The integration of the ALICE trigger system with sub-detectors Krivda, M.; Barnby, L.; Bombara, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Letnik:
617, Številka:
1
Journal Article
Recenzirano
The ALICE Trigger electronics (TRG) has been installed in the experimental cavern and tested with each of the detectors, both individually (‘standalone’ mode) and in ‘global’ runs, i.e. those ...involving other detectors. Global runs were performed with cosmic ray triggers, and also during the LHC startup period in September 2008. In this paper the status of the trigger system will be reviewed, in particular describing recent extensions to the system.
We report the main results from experiment WA97 on the production of strange and multistrange hadrons at midrapidity in Pb+Pb, p+Pb and p+Be collisions at 158
A GeV/
c. A comparison with some of the ...available models is presented.
We propose a simple Glauber-type mechanism for the suppression of jet production up to transverse momenta of about 10 \(\mathrm {GeV}/c\) at RHIC. For processes in this kinematic region, the ...formation time is smaller than the interval between two successive hard partonic collisions and the subsequent collision influences the jet production. The number of jets then roughly scales with the number of participants. Proportionality to the number of binary collisions is recovered for very high transverse momenta. The model predicts suppression of jet production in \(d + {\mathrm {Au}}\) collisions at RHIC.
The WA97 experiment has measured the transverse mass (
m
T) spectra for negative hadrons (h
−) and strange particles produced at mid-rapidity in Pb−Pb collisions. The increased statistics of analysed ...data samples allowed us to perform a study of the spectra of K
0
S, Λ, Ξ, Ω and h
− as a function of the centrality of the collisions. The data, which correspond to the most central 40% of the total inelastic cross section, have been divided into four centrality classes according to the estimated number of nucleons taking part in the collision. The
m
T spectra, analysed separately for each centrality bin, exhibit only weak (≤ 15%) centrality dependence. The deviation of the Ω inverse slope from the linear dependence on the particle mass is confirmed even for the most central Pb−Pb collisions.
A study of the strangeness enhancement in Lead-Lead collisions with respect to proton-induced reactions is being carried out at the CERN SPS by the WA97 experiment: up to now, data from proton-Lead ...collisions have been used as a reference sample. In this paper we report on a study of particle production in proton-Beryllium collisions. These collisions are expected to constitute a better reference sample than p-Pb, because of the lighter target. The analysis of hyperon and negative particle production is presented and the results are compared with those previously obtained from Pb-Pb and p-Pb collisions.
Data on mean numbers of A, Ā, K’s and on the total number of pairs of strange valence quarks in final state hadrons in hadronic and nuclear collisions at CERN-SPS energies are studied as a function ...of the mean number < ncoll > of nucleon-nucleon collisions. Results give indications of an almost linear dependence over most of the region of < ncoll >. This in turn points out to strangeness being produced mostly in the central rapidity region of nucleon-nucleon collisions by a mechanism similar to a hard or semi-hard process. The available data are extrapolated to Pb+Pb interactions by two simple models, leading to . Observations exceeding these values of would give evidence of the onset of a new dynamical regime in Pb+Pb interactions.
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