44,590 research outputs found
Experimental aspects of colour reconnection
This report summarises experimental aspects of the phenomena of colour
reconnection in W+W- production, concentrating on charged multiplicity and
event shapes, which were carried out as part of the Phenomenology Workshop on
LEP2 Physics, Oxford, Physics Department and Keble College, 14-18 April, 1997.
The work includes new estimates of the systematic uncertainty which may be
attributed to colour reconnection effects in experimental measurements of Mw.Comment: 10 pages, 4 figures. To be published in proceedings of Phenomenology
Workshop on LEP2 Physics, Oxford 14-18 April 199
Payload/burned-out motor case separation system Patent
Payload/spent rocket engine case separation syste
W+W- Hadronic Decay Properties
Recent measurements of the properties of W+W- events produced in e+e-
collisions at Ecm=183 GeV at LEP are reviewed. The data are used to investigate
the predicted effects of final state interactions, specifically "colour
reconnection".Comment: 6 pages, 7 figures. To appear in the "Proceedings of the XXIX
International Conference on High Energy Physics", Vancouver, CA, 23-29 July
199
Seasonal changes in abundance of brown trout (Salmo trutta) and rainbow trout (s. gairdnerii) assessed by drift diving in the Rangitikei river, New Zealand
Numbers and approximate sizes of brown trout (Salmo trutta L.) and rainbow trout (5. gairdnerii Richardson) were estimated by snorkel divers at 6 sites in the middle reaches of the Rangitikei River, North Island, New Zealand, over 14 months. The results showed that different species and sizes of trout varied in abundance with time. The species of fingerling trout (6-12 cm FL) could not be identified because of their small size and shoaling behaviour. Rainbow trout abundance varied seasonally and was greatest in January and April (between 18 and 60 fish per kilometre) when fish between 23 and 38 cm FL were the most abundant size class. Brown trout abundance showed much less variation with time (between 5 and 36 fish per kilometre at most sites). Also in contrast to rainbow trout, the majority of brown trout were > 38 cm FL, and in June, when the greatest density was observed (56 fish per kilometre), 70 redds were seen at the same site. Two sites were dived within a 48 h period to test the variability of the method. Comparisons between the 3 dives at each site revealed no significant differences between the numbers offish in different species and size classes
Quinnat salmon (oncorhynchus tshawytscha) spawning in the Rangitikei river
The occurrence of adult quinnat salmon {Oncorhynchus tshawytscha (Walbaum)) in the Rangitikei River, North Island, New Zealand, has been confirmed on several occasions since 1922, but juvenile salmon have not previously been recorded. In late February 1981 a 79-mm-fork-length smolt was caught in a stranded side channel 180 km upstream from the mouth. This suggests that quinnat salmon can spawn successfully in this river
Gluon Correlators in the Kogan-Kovner Model
The Lorentz-invariant gluon correlation functions, corresponding to scalar
and pseudo-scalar glueballs, are calculated for Kogan's and Kovner's
variational ansatz for the pure SU(N) Yang-Mills wavefunctional.
One expects that only one dynamical mass scale should be present in QCD; the
ansatz generates the expected scale for both glueballs, as well as an
additional scale for the scalar glueball. The additional mass scale must
therefore vanish, or be close to the expected one. This is shown to constrain
the nature of the phase transition in the Kogan-Kovner ansatz.Comment: 9 pages, no figure
A new thermal vacuum facility at the Martin Marietta Waterton plant
A new thermal-vacuum facility has been recently completed at the Martin Marietta Waterton plant near Denver, Colorado. The facility was designed, fabricated, installed, and tested as a turn-key project by Pitt-Des Moines Inc. and CVI Inc. The chamber has a 5.49 M by 6.10 M (18 ft by 20 ft) flat floor and a half-cylindrical roof with a diameter of 5.49 M (18 ft). Both ends of the chamber have full cross section doors, with one equipped with translating motors for horizontal motion. The chamber is provided with four 0.91 M (36 inches) cryopumps to obtain an ultimate pressure of 9 x 10(exp -8) Torr (Clean-Dry-Empty). The thermal shroud is designed to operate at a maximum of -179 C (-290 F) with an internal heat input of 316 MJ/Hr (300,000 BTU/Hr) using liquid nitrogen. The shroud is also designed to operate at any temperature between -156 C (-250 F) and 121 C (+250 F) using gaseous nitrogen, and heat or cool at a rate of 1.1 C (2 F) per minute
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