Nucleus-nucleus collisions provide the unique opportunity to create and to investigate dense nuclear matter in the laboratory. The collision experiments address fundamental aspects of ...strong-interaction physics: the nuclear equation-of-state at high baryon densities, the modification of hadron properties in the dense nuclear medium, and the phase transition from hadronic matter to the quark-gluon plasma. The experimental results are relevant for our understanding of the dynamics of core-collapse supernovae, and of the structure of neutron stars. In particular, strange particles are promising diagnostic probes of dense nuclear matter. Existing experimental data, their theoretical interpretations, and future experiments will be discussed.
Differential production cross sections of K- and K+ mesons have been measured in Ni+Ni and Au+Au collisions at a beam energy of 1.5 A GeV. The K(-)/K(+) ratio is found to be nearly constant as a ...function of the collision centrality and system size. The spectral slopes and the polar emission pattern differ for K- and K+ mesons. These observations indicate that K+ mesons decouple earlier from the fireball than K- mesons.
A golden age for heavy-quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The ...early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the
B
-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations at BESIII, the LHC, RHIC, FAIR, the Super Flavor and/or Tau–Charm factories, JLab, the ILC, and beyond. The list of newly found conventional states expanded to include
h
c
(1
P
),
χ
c
2
(2
P
),
, and
η
b
(1
S
). In addition, the unexpected and still-fascinating
X
(3872) has been joined by more than a dozen other charmonium- and bottomonium-like “
XYZ
” states that appear to lie outside the quark model. Many of these still need experimental confirmation. The plethora of new states unleashed a flood of theoretical investigations into new forms of matter such as quark–gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of
,
, and
bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. Lattice QCD has grown from a tool with computational possibilities to an industrial-strength effort now dependent more on insight and innovation than pure computational power. New effective field theories for the description of quarkonium in different regimes have been developed and brought to a high degree of sophistication, thus enabling precise and solid theoretical predictions. Many expected decays and transitions have either been measured with precision or for the first time, but the confusing patterns of decays, both above and below open-flavor thresholds, endure and have deepened. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark–gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A prototype detector based on thin-walled segmented tubes has been developed and its parameters have been studied. The detector contains 360 registration channels with a straw diameter of 4
mm. The ...prototype’ granularity is 4
сm
2 and the length of insensitive region due to straw internal elements is less than 5% of its full sensitive area. Deterioration of the spatial resolution near these elements is observed for 1.0% of the detector sensitive area. The time and spatial parameters of the detector do not differ from those of conventional tracking detectors based on drift tubes.
Spatial resolution of thin-walled high-pressure drift tubes Davkov, V.I.; Gregor, I.; Haas, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2011, Letnik:
634, Številka:
1
Journal Article
Recenzirano
A small prototype detector based on high pressure thin-walled tubes (straws) has been developed and its parameters have been studied on a bench at JINR, Dubna, and SPS at CERN. The inner diameter of ...the straws is 9.53
mm. The pressure of the active gas mixture Ar/CO
2 (80/20) was varied from 1 to 5
bar. The best spatial resolution achieved in this pressure range is ∼40
μm. Both the high efficiency and high rate capability are retained.
Differential production cross sections of K
− and K
+ mesons have been measured as function of the polar emission angle in Ni
+
Ni collisions at a beam energy of 1.93
A
GeV. In near-central ...collisions, the spectral shapes and the widths of the rapidity distributions of K
− and K
+ mesons are in agreement with the assumption of isotropic emission. In non-central collisions, the K
− and K
+ rapidity distributions are broader than expected for a single thermal source. In this case, the polar angle distributions are strongly forward–backward peaked and the nonisotropic contribution to the total yield is about one third both for K
+ and K
− mesons. The K
−/K
+ ratio is found to be about 0.03 independent of the centrality of the reaction. This value is significantly larger than predicted by microscopic transport calculations if in-medium modifications of K mesons are neglected.
Gas Chromatography–Olfactometry was performed on Tahitian vanilla extracts in order to highlight its flavor specificity. The results stressed that Tahitian vanilla flavor was very rich. 61 odorant ...zones were identified, 38 of them were attributed to an odor-active component. Among them, anisaldehyde and guaiacol were found to be the key flavor compounds of Tahitian vanilla. They were representative of the predominant “spicy-anise” and “phenolic” odor families. Moreover, three cultivars of Tahitian vanilla were characterized thanks to their GC–O profile, highlighting the diversity existing among Tahitian vanilla flavor, and providing prospects for valorizing them as well.
► GC-O analysis performed on Vanilla × tahitensis flavor. ► Detection of 61 odorant zones and identification of 38 odor active compounds. ► Anisaldehyde and guaiacol are key components of the complex Tahitian vanilla flavor. ► Each Polynesian cultivar shows a specific “sensory fingerprint”.
The CBM Physics Book Friman, Bengt; Höhne, Claudia; Leupold, Stefan ...
2011, 20110217, 2014-07-30, Letnik:
814
eBook, Book
This exhaustive survey is the product of a four-year effort by leading researchers in the field to produce both a readable introduction and a yardstick for the upcoming experiments using heavy ion ...collisions that will examine the properties of nuclear matter.
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