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A search for non-qq¯ mesons in central production

Kirk, Andrew (1989)
Ph.D. thesis, University of Birmingham.

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This thesis presents a search for non-qq¯ mesons produced in the central region in the reaction pp -> Pf (X0) Ps at 300 GeV/c, where the subscripts f and s indicate the fastest and slowest particles in the laboratory respectively and X0 represents the central system that is presumed to be produced by double exchange processes. Results are presented of an analysis of the decay of X0 to K0sK±π+, K+K-K+K- and π+π-π+π-.
In the K0sK±π+ channel clear f1(1285) and f1(1420) signals are seen. A spin parity analysis shows that both are consistent with being 1++ states. The f1(1420) is found to decay only to K*K¯ and no 0-+ wave is required to describe the data. The production of the f1(1285) as a function of energy is not the same as that for the f1(1420) whose cross section is found to be constant with energy.
In the K+K-K+K- channel ΦΦ production has been observed and the ratio σ(ΦK+K-)/σ(ΦΦ) is
1.0±0.3. The cross-section for central production of ΦΦ is found to be the same at 300 GeV/c and 85 GeV/c. An angular analysis of the ΦΦ system favours JP = 2+ over 0¯.
The π+π-π+π- mass spectrum shows evidence for the f1(1285) with a mass of 1281± 1 MeV and a width of 31 ± 5 MeV. In addition there is evidence for two new enhancements at masses of 1449± 4 and 1901± 13 MeV with widths of 78± 18 and 312±61 MeV respectively. An analysis of the state at 1.45 GeV indicates that it is not a π+π-π+π- decay mode of the f1(1420) or ι/ε(1440).

Type of Work:Ph.D. thesis.
Supervisor(s):Bloodworth, Ian and Kinson, John B
School/Faculty:Faculties (to 1997) > Faculty of Science
Department:School of Physics and Space Research
Keywords:particle physics
Subjects:QC Physics
Institution:University of Birmingham
ID Code:8069
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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