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.
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 reactions
pp→
p
f
(
X
0)
p
s
, where
X
0 is observed decaying to
π
0
π
0
π
0
π
0 ,
π
+
π
−
π
+
π
− and
π
+
π
−
π
0
π
0 , have been studied at 450 GeV/
c. There is evidence for an
a
2(1320)
π ...decay mode of the
η
2(1645) and
η
2(1870) in the
π
+
π
−
π
0
π
0 and
π
+
π
−
π
+
π
− final states. The
f
2(1950) is consistent with being a single resonance with a dominant
f
2(1270)
ππ decay mode. The
f
0(1370) is found to decay dominantly to
ρρ while the
f
0(1500) is found to decay to
ρρ and
σσ.
A study of the
f
1(1285) and
f
1(1420) produced in central pp interactions has been performed. For the first time in a single experiment the branching fractions of both mesons in all major decay ...modes have been determined. Both the
f
1(1285) and
f
1(1420) are consistent with being produced by double Pomeron exchange.
The reaction
pp→
p
f
(
ηη)
p
s
has been studied at 450 GeV/c. For the first time a partial wave analysis of the centrally produced
ηη system has been performed. Signals for the
f
0(1500),
f
0(1710) ...and
f
2(2150) are observed and the decay branching fractions of these states are determined.
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.
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.
A partial wave analysis of the centrally produced eta pi0 and eta pi- channels has been performed in pp collisions using an incident beam momentum of 450 GeV/c. Clear a0(980) and a2(1320) signals ...have been observed in S and D+ waves respectively. The dPT, phi and |t| distributions of these resonances are presented.
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