Photons produced in pp interactions at 450 GeV/c were detected by reconstructing the e+e− pairs of photon conversions in a 1 mm thick lead sheet placed in front of the MWPCs of the OMEGA spectrometer ...at CERN. A soft photon signal 4.1±0.8 times the inner bremsstrahlung prediction was observed in the forward rapidity region (yc.m.s.⩾1.2), thus extending the domain of the anomalous soft photon effect seen already in K+p, π+p and π−p interactions.
In this Letter we present additional experimental characteristics of anomalous soft photon radiation observed in π−p interactions at 280 GeV/c in the CERN experiment WA91, together with a ...re-calculated ratio of the observed direct soft photon signal to the expected level of the hadronic inner bremsstrahlung, which is found to be 5.3±1.0. The other presented characteristics, energy dependence and angular distributions of direct soft photons, show the similarity of the observed signal to the expected hadronic bremsstrahlung behaviour.
Photons produced in
π
−p interactions at 280 GeV/
c were detected by reconstructing the e
+e
− pairs produced via the materialisation of the photons in a 1 mm thick lead sheet placed in front of the ...MWPC's of the OMEGA spectrometer at CERN. A soft photon signal 7.8 ± 1.5 times the Q.E.D. inner bremsstrahlung prediction was observed confirming the results of a previous experiment.
Results from NA57 Dainese, A.
Nuclear physics. A,
08/2006, Letnik:
774
Journal Article
Recenzirano
Odprti dostop
The NA57 experiment has measured the production of strange and multi-strange hadrons in heavy-ion collisions at the CERN SPS. After briefly introducing the NA57 apparatus and analysis procedures, we ...present recent results on strangeness enhancement in Pb+Pb relative to p+Be collisions, on the study of the
m
T
distributions of strange particles, and on central-to-peripheral nuclear modification factors in Pb+Pb collisions at top SPS energy.
We present central-to-peripheral nuclear modification factors, RCP, for the pT distributions of KS0, Λ, Λ¯, and negatively charged particles, measured at central rapidity in Pb–Pb collisions at top ...SPS energy. The data cover the 55% most central fraction of the inelastic cross section. The KS0 and ΛRCP(pT) are similar in shape to those measured at sNN=200 GeV at RHIC, though they are larger in absolute value. We have compared our KS0RCP data to a theoretical calculation. The prediction overestimates the data at pT≈3–4 GeV/c, unless sizeable parton energy loss is included in the calculation.
PDF
