Invariant pT spectra and rapidity densities covering a large rapidity range (−0.1<y<3.5) are presented for π± and K± mesons from central Au + Au collisions at sNN=62.4 GeV. The mid-rapidity yields of ...meson particles relative to their anti-particles are found to be close to unity (π−/π+∼1, K−/K+∼0.85) while the anti-proton to proton ratio is p¯/p∼0.49. The rapidity dependence of the π−/π+ ratio is consistent with a small increase towards forward rapidities while the K−/K+ and p¯/p ratios show a steep decrease to ∼0.3 for kaons and 0.022 for protons at y∼3. It is observed that the kaon production relative to its own anti-particle as well as to pion production in wide rapidity and energy ranges shows an apparent universal behavior consistent with the baryo-chemical potential, as deduced from the p¯/p ratio, being the driving parameter.
The proton-to-pion ratios measured in the BRAHMS experiment for
Au
+
Au
and
p
+
p
collisions at
s
N
N
=
62.4
and 200 GeV are presented as a function of transverse momentum and collision centrality at ...selected pseudorapidities in the range of 0–3.8. A strong pseudorapidity dependence of these ratios is observed. We also compare the magnitude and
p
T
-dependence of the
p
/
π
+
ratios measured in
Au
+
Au
collisions at
s
N
N
=
200
GeV
and
η
≈
2.2
with the same ratio measured at
s
N
N
=
62.4
GeV
and
η
=
0
. The great similarity found between these ratios throughout the whole
p
T
range (up to
2.2
GeV
/
c
) is consistent with particle ratios in
A
+
A
collisions being described with grand-canonical distributions characterized by the baryo-chemical potential
μ
B
. At the collision energy of 62.4 GeV, we have observed a unique point in pseudorapidity,
η
=
3.2
, where the
p
/
π
+
ratio is independent of the collision system size in a wide
p
T
-range of
0.3
⩽
p
T
⩽
1.8
GeV
/
c
.
We review the main results obtained by the BRAHMS Collaboration on the properties of hot and dense hadronic and partonic matter produced in ultrarelativistic heavy ion collisions at RHIC. A ...particular focus of this paper is to discuss to what extent the results collected so far by BRAHMS, and by the other three experiments at RHIC, can be taken as evidence for the formation of a state of deconfined partonic matter, the so-called quark–gluon plasma (QGP). We also discuss evidence for a possible precursor state to the QGP, i.e., the proposed color glass condensate.
A systematic review of arthrosis of finger joints in relation to occupational exposure revealed 11 epidemiological studies and 13 case reports. All studies but one were cross-sectional rendering ...demonstration of causation problematic. The reviewed literature also had drawbacks relating to exposure classification, confounding and non-attendance. Four studies showed an association between extensive use of precision grip and development of arthrosis of the distal interphalangeal joints of fingers. Two studies found an association between forceful gripping and the occurrence of arthrosis involving the metacarpophalangeal joints. Arthrosis of the proximal interphalangeal joints and first carpo-metacarpal joints was not related to any specific occupational task. Well-designed studies are needed to further elucidate this possible occupational hazard.
π+π+ and π−π− correlations from 200 GeV per nucleon S + Pb collisions and π+π+ correlations from 450 GeV p + Pb collisions measured by the focussing spectrometer of CERN experiment NA44 are ...presented. The large data set which emphasizes small values of momentum difference allows multi-dimensional analysis along with the more traditional one-dimensional parameterization to characterize the pion emission source. It is found that the three radius parameters are similar and large compared to the projectile radius. This can be explained by pion scattering in the final state hadronic system.
The first measurements of xF-dependent single-spin asymmetries of identified charged hadrons, pi+/-, K+/-, and protons, from transversely polarized proton-proton collisions at 62.4 GeV at RHIC are ...presented. Large asymmetries are seen in the pion and kaon channels. The asymmetries in inclusive pi+ production, AN(pi+), increase with xF from 0 to approximately 0.25 and AN(pi-) decrease from 0 to approximately -0.4. Observed asymmetries for K- unexpectedly show positive values similar to those for K+, increasing with xF, whereas proton asymmetries are consistent with zero over the measured kinematic range. Comparisons of the data with predictions of QCD-based models are presented.
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