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.
A coupled channel analysis of the centrally produced
K
+
K
−and
π
+
π
−final states has been performed in
pp collisions at an incident beam momentum of 450 GeV/c. The pole positions and branching ...ratios to
ππ and
K
K
of the
f
0(980),
f
0(1370),
f
0(1500) and
f
0(1710) have been determined. A systematic study of the production properties of all the resonances observed in the
π
+
π
−and
K
+
K
−channels has been performed.
The reaction pp -> pf (eta eta) ps has been studied at 450 GeV/c. For the first time a partial wave analysis of the centrally produced eta eta system has been performed. Signals for the f0(1500), ...f0(1710) and f2(2150) are observed and the decay branching fractions of these states are determined.
The production and decay properties of the
f
0(1370),
f
0(1500),
f
0(2000) and
f
2(1950) have been studied in central pp interactions at 450 GeV/c. The
dP
T
,
φ and |
t| distributions of these ...resonances are presented. For the
J=0 states, the
f
0(1370) and
f
0(2000) have similar
dP
T
and
φ dependences. These are different to the
dP
T
and
φ dependences of the
f
0(980),
f
0(1500) and
f
0(1710). For the
J=2 states the
f
2(1950) has different dependences to the
f
2(1270) and
f
2
′(1520). This shows that the
dP
T
and
φ dependences are not just
J phenomena.
A partial wave analysis of the centrally produced
π
+
π
− channel has been performed in
pp collisions using an incident beam momentum of 450 GeV/c. An unambiguous physical solution has been found. ...Evidence is found for the
f
0(980),
f
0(1300),
f
0(1500) and
f
j
(1710) with
J = 0 in the
S-wave. The ϱ(770) is observed dominantly in the
P
0
−-wave and the
f
2(1270) is observed dominantly in the
D
0
−-wave. In addition, there is evidence for a broad enhancement in the
D-wave below 1 GeV.
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.
The production and decay properties of the f0(1370), f0(1500), f0(2000) and f2(1950) have been studied in central pp interactions at 450 GeV/c. The dPT, phi and |t| distributions of these resonances ...are presented. For the J = 0 states, the f0(1370) and f0(2000) have similar dPT and phi dependences. These are different to the dPT and phi dependences of the f0(980), f0(1500) and f0(1710). For the J = 2 states the f2(1950) has different dependences to the f2(1270) and f2'(1520). This shows that the dPT and phi dependences are not just J phenomen
The reaction
pp→
p
f
p
s
(
K
+
K
−
K
+
K
−) in which the
K
+K
−K
+K
−
system is centrally produced has been studied at 450 GeV/c.
φφ production has been found to dominate this reaction and is ...compatible with being produced by double Pomeron exchange. An angular analysis of the
φφ system favours
J
PC
=2
++ and its
dP
T
dependence is similar to that observed for glueball candidates.
A study has been made of pseudoscalar mesons produced centrally in pp interactions. The results show that the
η and
η
′ appear to have a similar production mechanism which differs from that of the
π
...0. The production properties of the
η and
η
′ are not consistent with what is expected from double Pomeron exchange. In addition the production mechanism for the
η and
η
′ is such that the production cross section are greatest when the azimuthal angle between the
p
T
vectors of the two protons is 90 degrees.
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