Hanbury-Brown and Twiss (HBT) interferometry is used to study the space-time evolution of nuclear collisions at CERN energies. Pairs of identified pions, kaons and protons are studied by NA44 for a ...variety of collisions systems ranging from p-Pb to PbPb. The pion and kaon correlation data from the 1994 and 1995 Pb runs are compared to published data. The systematic increase in radius parameter with system size is continued in the Pb data sample. Model comparision stress the importance of scattering in the evolution of the collision.
The NA44 experiment has measured single-particle inclusive spectra for charged pions, kaons, and protons as a function of transverse mass near midrapidity in 158A GeV/c Pb+Pb collisions. From the ...particle mass dependence of the observed m(T) distributions, we are able to deduce a value of about 120 MeV for the temperature at thermal freeze-out. From the observed ratios of the rapidity densities, we find values of the chemical potentials for light and strange quarks and a chemical freeze-out temperature of approximately 140 MeV.
Two-neutron interferometry measurements Pluta, J.; Bizard, G.; Désesquelles, P ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
1998, Letnik:
411, Številka:
2
Journal Article
Recenzirano
The results of analysis of two-neutron correlations in the region of small relative velocities are presented. The influence of spurious correlations on the form of correlation function is considered ...in detail. Data analysis and computer simulations were performed for a specific detector configuration with close angular position and different distances between the target and detector modules. The features of different methods of cross-talk elimination are examined. The proposed method is verified and the first results of cross-talk free correlation functions are presented for the ArAu reaction at
60
MeV
u
measured with the DEMON detector at GANIL.
Proton-neutron correlation functions measured in Ar induced reactions at 30 MeV per nucleon are presented. Significant suppression of correlation as compared to that expected from nuclear final state ...attraction is observed. This effect can only partly be due to Coulomb repulsion of the protons from the emitting nucleus. Three-body classical and quantum calculations show that substantial correlations survive even in a strong Coulomb field of the emitter.
Recent results of analyses on hadron spectra from the focusing spectrometer experiment NA44 are presented. One-, two- and three-particle hadron spectra in the mid-rapidity region at CERN/SPS energy ...have been measured. The
m
T
inverse-slopes of proton and anti-proton in collision systems from p+A to Pb+Pb are discussed. Spectra of deuteron, triton and anti-deuteron are presented, and the flow effect on the composite particle spectra are discussed. The two-particle interferometry analysis is made for the π
±π
± and
K
+
K
+ correlations in the central Pb+Pb collisions, and the dependences of interferometric parameters on the transverse mass and the multiplicity are discussed.
Coalescence, interferometry and flow Murray, Michael; Bearden, I.G.; Bøggild, H. ...
Nuclear Physics A,
1999, Letnik:
661, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
NA44 has measured proton and deuteron distributions from
SS and
SPb collisions at 200 GeV/
c and
PbPb collisions at 158 GeV/
c. The mean
p
T
of both protons and deuterons grows with system size but ...the deuterons are somewhat slower than the protons. The phase space density of protons falls with
m
T
but increases for larger systems. The phase space density of
p̄s is much lower than of protons while their average freeze-out radii are similar. The proton source size increases with system size but not as rapidly as the pion source. For
PbPb collisions, all radii lie on a single curve.
We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at 200 GeV using the STAR detector ...at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage -1.3, 1.3. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes.
In ultraperipheral relativistic heavy-ion collisions, a photon from the electromagnetic field of one nucleus can fluctuate to a quark-antiquark pair and scatter from the other nucleus, emerging as a ...rho{0}. The rho{0} production occurs in two well-separated (median impact parameters of 20 and 40 F for the cases considered here) nuclei, so the system forms a two-source interferometer. At low transverse momenta, the two amplitudes interfere destructively, suppressing rho{0} production. Since the rho{0} decays before the production amplitudes from the two sources can overlap, the two-pion system can only be described with an entangled nonlocal wave function, and is thus an example of the Einstein-Podolsky-Rosen paradox. We observe this suppression in 200 GeV per nucleon-pair gold-gold collisions. The interference is 87%+/-5%(stat.)+/-8%(syst.) of the expected level. This translates into a limit on decoherence due to wave function collapse or other factors of 23% at the 90% confidence level.
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