J.B. Kinson

A coupled channel analysis of the centrally produced K+ K- and π+ π- final states in pp interactions at 450 GeV/c

A coupled channel analysis of the centrally produced K+K- and pi+pi- final states has been performed in pp collisions at an incident beam momentum of 450 GeV/c. The pole positions and branching ratios to pipi and KK of the f0(980), f0(1370), f0(1500) and f0(1710) have been determined. A systematic study of the production properties of all the resonances observed in the pi+pi- and K+K- channels has been performed.Abstract 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 f0(980), f0(1370), f0(1500) and f0(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 spin analysis of the 4π channels produced in central pp interactions at 450 GeV/c

The reactions pp ! pf(X 0 )ps ,w here X 0 is observed decaying to 0000 , + + and + 00 , have been studied at 450 GeV/c. There is evidence for an a2(1320) decay mode of the 2(1645) and 2(1870) in the + 00 and + + nal states. The f2(1950) is consistent with being a single resonance with a dominant f2(1270) decay mode. The f0(1370) is found to decay dominantly to while the f0(1500) is found to decay to and .

A measurement of the branching fractions of the f1(1285) and f1(1420) produced in central pp interactions at 450 GeV/c

Abstract 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.A study of the f1(1285) and f1(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 f1(1285) and f1(1420) are consistent with being produced by double Pomeron exchange.

A study of the f0(1370), f0(1500), f0(2000) and f2(1950) observed in the centrally produced 4π final states

Abstract 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.

Study of the reaction K+p→ K*0 (890) Δ++ from 4.6-16.0 GeV/c

Abstract A systematic analysis is presented on the reaction K + p → K ∗0 (890) Δ ++ for nine incident momenta between 4.6–16.0 GeV/ c . Cross sections, differential cross sections and vector meson single density matrix elements are given. As a function of energy, little if any change is observed in either the shapes of the differential cross sections or in the values of the density matrix elements. The data are interpreted in terms of current ideas on t -channel exchange mechanisms.

A study of the ωω channel produced in central pp interactions at 450 GeV/c

The reaction pp ! pf(!!)ps has been studied at 450 GeV/c and a spin analysis of the !! channel has been performed for the rst time in central production. Evidence is found for the f2(1910) in the J PC =2 ++ wave with spin projection JZ = 2. This is the only state observed in central production with spin projection JZ =2 . ItsdPT and dependencies are similar to those observed for other glueball candidates. In addition, evidence is found for a state with J PC =4 ++ consistent with the f4(2300). The f0(2000), previously observed in the

A study of the ηη' and η'η' channels produced in central pp interactions at 450 GeV/c

Abstract The reactions pp → p f ( X 0 ) p s , where X 0 is observed decaying to ηη ′ and η ′ η ′ , have been studied at 450 GeV/c. This is the first time that these channels have been observed in central production and only the second time that the η ′ η ′ channel has been observed in any production mechanism. In the ηη ′ channel there is evidence for the f 0 (1500) and a peak at 1.95 GeV. The η ′ η ′ channel shows a peak at threshold which is compatible with having J PC =2 ++ and spin projection J Z =0.

Observation of vertex factorisation breaking in central pp interactions

Abstract Central π+π− events produced in pp interactions are studied in terms of correlations between the outgoing protons. It is observed there is more ϱ0(770) and f2(1270) production in reactions where the outgoing protons are on opposite sides of the beam. This effect is not attributable to the trigger or the experimental acceptance, and suggests that the vertices do not factorise.

A study of the centrally produced K∗(892)K∗(892)and φω systems in pp interactions at 450 GeV/c

Abstract A study of the reactions pp → p f p s ( K + K − π + π − ) and pp → p f p s ( K + K − π + π − π 0 ) shows evidence for the K ∗ (892) K ∗ (892) and φω channels respectively. The K ∗ (892) K ∗ (892) mass spectrum shows a broad distribution with a maximum near threshold and an angular analysis shows that it is compatible with having J P =2 + . The behaviour of the cross-section as a function of centre of mass energy, and the four momentum transfer dependence, are compatible with what would be expected if the K ∗ (892) K ∗ (892) system was produced via double Pomeron exchange. The dP T behaviour of the φω channel is similar to what has been observed for all the undisputed q q states. In contrast, the dP T behaviour of the K ∗ (892) K ∗ (892) final state is similar to what has been observed for the φφ final state and for previously observed glueball candidates.A study of the reactions pp ->pfps(K+K-pi+pi-) and pp ->pfps(K+K-pi+pi-pi0) shows evidence for the K*K* and phi omega channels respectively. The K*K* mass spectrum shows a broad distribution with a maximum near threshold and an angular analysis shows that it is compatible with having JP = 2+. The behaviour of the cross-section as a function of centre of mass energy, and the four momentum transfer dependence, are compatible with what would be expected if the K*K* system was produced via double Pomeron exchange. The dPT behaviour of the phi omega channel is similar to what has been observed for all the undisputed qqbar states. In contrast, the dPT behaviour of the K*K* final state is similar to what has been observed for the phi phi final state and for previously observed glueball candidates.

Λ, Ξ and Ω production in PbPb collisions at 158 A GeV/c

Abstract Enhanced production of strange baryons and anti-baryons at central rapidity in S-W and S-z.sbnd;S with respect to p-A reactions has been reported by the CERN experiments WA85 and WA94. The WA97 experiment is extending such a study to Pb Pb collisions making use of the newly developed silicon pixel detectors. Results on Λ, Ξ − and Ω − production in Pb Pb collisions at 158 A GeV/ c at central rapidity are presented. Transverse mass spectra and particle ratios are presented. Hyperon yields are given as a function of the collision centrality and compared with those obtained from p-Pb collisions using the same experimental setup.