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HEP Seminars

10 Apr 2021

UCL HEP Seminars 1994

7th December 1994 : Dr Allan Skillman

Inclusive Strange Vector and Tensor Meson Production in Hadronic Z Decays

Measurements have been made in the OPAL experiment at LEP of the inclusive production of strange vector phi(1020) and K*(892) mesons, and the neutral tensor meson K*(1430). The measurements for the vector states update previously published results based on lower statistics, while the K*(1430) rate represents the first measurement of a strange tensor state in Z0 decay. Both the overall production rates, and normalised differential cross sections for the vector states, have been compared to JETSET and HERWIG predictions. The peak positions in the xi = ln(1/xp) distributions have been measured and found to be consistent with measurements of other hadron states.

Wednesday 30th November 1994 : Dr Jeff Forshaw (DRAL)

Diffractive Vector Meson Production at Large Momentum Transfer

HERA is able to observe diffractive production of vector mesons. Their observation at large momentum transfer will provide important information regarding the nature of the pomeron in QCD

Wednesday 23rd November 1994 : Dr Nick Brook (Glasgow)

The Hadronic Final State in Deep Inelastic Scattering at Zeus

The general characteristics of the hadronic final state in deep inelastic, neutral current electron-proton interactions at ZEUS are investigated for Q2 > 10 GeV2. The general properties of events with a large rapidity gap are investigated and compared to events without a rapidity gap. The kinematic properties of the jets in 2-jet events are measured and compared to NLO calculations. Fragmentation effects are investigated in the current fragmentation region. The data are used to study QCD coherence effects in DIS and to compare with corresponding e+e- data in order to test the universality of quark fragmentation.

Wednesday 2nd November 1994 : Prof Elliot Leader

The Present Status of Polarised Deep Inelastic Scattering

The unexpected results of the EMC experiment in 1987, using a longitudinally polarised lepton beam on a longitudinally polarised hydrogen target, with its suggestion of a "spin crisis in the parton model" catalysed an enormous amount of theoretical and experimental work. What that was regarded as a trivial extension of the unpolarised case is now seen to be a rich field of its own, full of subtleties. Several new experiments reported results during 1993/4. The first data on neutrons appeared and led initially to claims that the fundamental Bjorken sum rule was violated. The seminar will cover both the theory and phenomenology .

Friday 28th October 1994 : Dr Lev Chekhtman (CERN/Novosibirsk)

Microstrip Gas Chambers - Possible Applications for X-ray Detection

Existing low-dose digital X-ray systems have much worse spatial resolution than photographic film/screen techniques. Microstrip gas chambers offer resolutions of around 100 microns and may have larger area than solid-state strip or CCD detectors.

Wednesday 26th October 1994 : Dr Robert Bingham (DRAL)

Particle Acceleration in Plasmas using High Powered Lasers

The generation of relativistic plasma waves in low density plasmas is important in the quest for producing ultra-high acceleration gradients for accelerators. At present two methods are being pursued vigorously to achieve ultra-high acceleration gradients. The first is the beat wave mechanism which uses conventional long pulses (>100 ps) modest intensity lasers (I ~ 10E14 Watts/cm2 - 10E16 Watts/cm2) and the second uses the new breed of compact high brightness lasers (< 1 ps) and intensities > 10E18 Watts/cm2. With the development of these compact short pulse high brightness lasers new areas of study for laser matter interactions is opening up. In the ultra-high intensity regime laser plasma interactions are highly nonlinear and relativistic leading to new phenomenon such as plasma wakefield excitation for particle acceleration, relativistic self-focusing, remote guiding of laser beams, harmonic generation and photon acceleration.

Friday 21st October 1994 : Dr John Hassard (IC)

Diamond Detectors: Towards the Frontiers of Technology

Diamond films are strictly insulators, but they are excellent photoconductors (and conductors of heat). As detectors for ionising particles they may be especially interesting for high-radiation environments in nuclear medicine and at future particle colliders.

Wednesday 12th October 1994 : Prof Tegid Jones, Prof David Miller, Dr Mark Thomson

Glasgow Conference Review

Tegid, David and Mark will be telling us about the highlights of that sunny week in July, north of the border.