The NA60 experiment at the CERN SPS has studied $\phi$ meson production in In-In collisions at 158A GeV via both the $K^+K^-$ and the $\mu^+\mu^-$ decay channels. The yields and inverse slope ...parameters of the $m_T$ spectra observed in the two channels are compatible within errors, different from the large discrepancies seen in Pb-Pb collisions between the hadronic (NA49) and dimuon (NA50) decay channels. Possible physics implications are discussed.
Charmonium production in p–A collisions is a unique tool for the study of the interaction of bound cc states in nuclear matter. It can provide details on the basic features of the resonance formation ...mechanism and, in particular, on its non-perturbative aspects. In this Letter, we present an experimental study of charmonia and Drell–Yan production in proton–nucleus collisions at 450 GeV/c. The results are analyzed in the framework of the Glauber model and lead to the values of the nuclear absorption cross-section σabspA for J/ψ and ψ′. Then, we compare the J/ψ absorption in proton–nucleus and sulphur–uranium interactions, using NA38 data. We obtain that, for the J/ψ, σabspA and σabsSU are compatible, showing that no sizeable additional suppression mechanism is present in S–U collisions, and confirming that the anomalous J/ψ suppression only sets in for Pb–Pb interactions.
The Neutron Zero Degree Calorimeter for the ALICE experiment Arnaldi, R.; Chiavassa, E.; Cicalò, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2006, Volume:
564, Issue:
1
Journal Article
Peer reviewed
In this paper, we present the performance of the Neutron Zero Degree Calorimeter (ZN) for the ALICE experiment. The ZN is a quartz-fiber spaghetti calorimeter, which will measure the energy of the ...spectator neutrons in heavy ion collisions at the CERN LHC. Its principle of operation is based on the detection of the Cherenkov light produced by the charged particles of the shower in silica optical fibers, embedded in a W-alloy absorber. The detector was tested at CERN SPS using positive hadron and positron beams with momenta ranging from 50 to
150
GeV
/
c
. The response of the calorimeter, the energy resolution, the localizing capability, the signal uniformity and the transverse profile of the detectable hadronic shower are presented.
Soil gravel content affects many soil physical properties, as well as crop yield. Little is known regarding the influence of soil gravel content on growth and nutrient uptake of durum wheat (Triticum ...durum Desf.). The accumulation of nitrogen and phosphorous during the vegetative and reproductive periods and the contribution of pre-anthesis assimilates to grain N and P content have been evaluated in two durum wheat varieties grown on soils with 0, 10, 20 and 30% gravel content. The two varieties showed similar behaviour and the increase of soil gravel decreased plant biomass during the entire biological cycle. Nitrogen and P concentration of all plant parts was not affected by soil gravel content, while N and P content was greatly reduced, owing to the effect on dry matter yield. Post-anthesis accumulation and remobilization of N and P were greatly reduced: the decrease from gravel-free soil to 30% gravel content was about 41 kg N ha â1 and 4 kg P ha â1 for the former and 14 kg N ha â1 and 2 kg P ha â1 for the latter. The differences in growth rate were attributed to differences in development of the root system due to the restricted soil volume.
The NA60 experiment studies open charm and prompt dimuon production in proton-nucleus and nucleus-nucleus collisions at the CERN SPS. During 2003 the experiment collected data in Indium-Indium ...collisions at 158 GeV per nucleon. Almost 240 million dimuon events were recorded. New results on J/\(\psi\) suppression, open-charm production and low mass dimuons should help clarify some interesting questions left open by previous experiments. After a brief detector description, this paper focuses on the analysis of the low mass dimuons. Preliminary results are presented on the \(\phi/\omega\) production cross section ratios and on the \(\phi\) transverse momentum distributions, both as a function of collision centrality.
This biennial
Review summarizes much of particle physics. Using data from previous editions, plus 2778 new measurements from 645 papers, we list, evaluate, and average measured properties of gauge ...bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on CKM quark-mixing matrix,
V
ud
&
V
us
,
V
cb
&
V
ub
, top quark, muon anomalous magnetic moment, extra dimensions, particle detectors, cosmic background radiation, dark matter, cosmological parameters, and big bang cosmology.
A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full
Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website:
http://pdg.lbl.gov.
The identification of the isovector member of the scalar nonet plays a fundamental role in fixing the properties of the other members and, therefore, in the possible identification of an extra state ...as the glueball candidate. After more than 20 years of experiments on this subject the situation has not yet been clarified. A review of the experimental results coming both from \(\bar{p}p\) annihilation and the \(\pi p\) reaction is presented in this paper.
The zero degree calorimeters (ZDCs) for the ALICE experiment will measure the energy of the spectator nucleons in heavy ion collisions at the CERN LHC. The dipole magnets of the LHC beam optics will ...separate the ion beams from the spectator protons; the spectator protons and neutrons will be respectively detected by the proton (ZP) and the neutron (ZN) calorimeters. Since all the spectator nucleons have the same energy, the calorimeter response is proportional to their number, providing a direct information on the centrality of the collision. ZDCs are spaghetti calorimeters, which detect the Cherenkov light produced by the shower particles in silica optical fibers embedded in a dense absorber. The technical characteristics of ZP and ZN detectors are described. The calorimeters have been tested at the CERN SPS using pion and electron beams with momenta ranging from 50 to 200 GeV/c; the ZN detector behaviour has also been studied with an indium beam of 158 GeV/c per nucleon. The beam test results are presented: the calorimeters response, the energy resolution and the localizing capability. Also the signal uniformity and a comparison between the transverse profile of the hadronic and electromagnetic shower are discussed. Moreover the differences between the ZP detector responses to protons and pions of the same energy have been investigated, exploiting the proton contamination in the positive pion beams.
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