118367014
The General QCD parametrization and the hierarchy of its parameters: Why some simple models of hadrons work so well
After summarizing the basic points of the general QCD parametrization (GP) we discuss systematically its applications to the properties of the lowest families of baryons and mesons. We show how the hierarchy of the parameters in the GP emerges clearly in the properties of hadrons. Among other things, it explains why simple models can work reasonably well and clarifies the relationship between current and constituent quarks. More details on the hadron properties discussed with the GP appear from the list of secrions at the beginning of the paper.
124837005
SEARCH FOR QUARKS WITH THE FERROMAGNETIC LEVITATION ELECTROMETER
14665617
Comment on "Chiral symmetry and the intrinsic structure of the nucleon"- by D.B.Leinweber,A.W.Thomas and R.D.Young
Some remarks are presented on a recent paper (Leinweber,Thomas and Young, Phys.Rev.Lett. 86, 5011, 2001). In particular a statement of the above paper on the fact that the ratio between the magnetic moments of proton and neutron should remain constant at -3/2, independent of the change of the quark mass is discussed on the basis of the general parameterization.
120916653
The relation between QCD and constituent quark models
120776511
The non-relativistic quark model
The classification scheme and decay properties of hadron states are investigated in the framework of the non relativistic quark model. The main successes and the unsolved difficulties of the model are presented indicating the future work which could be done to understand and exploit the non-relativistic quark ideas.РезюмеИсследованы схема классификации и распадные свойства адронов в рамках статической модели кварков. Изложены главные успехи и нерешенные проблемы модели, указывая задачи, которые должны быть решены для лучшего понимания и использования нерелятивистских идей.
119592224
New Results in the Search of Quarks in Matter by the Magnetic Levitation Electrometer
Abstract The results of many runs performed levitating in succession several spheres without opening the levitation chamber show the existence of an additional (magneto-electric) force acting on the sphere. Ignoring this force in the analysis of the data produces “spurious” fractional charges.
123005204
REAL-TIME MONITORING OF BEAM-BEAM MODES AT LEP
By slightly exciting one of two colliding bunches in LEP, it is possible to enhance the eigenfrequencies of the resonant system of the two bunches coupled by the space charge force. The LEP Qmeter has been adapted to detect, among these excited frequencies, the so called - and - modes, whose distance is proportional to the luminosity. A real time display of these quantities provides the Operators with an effective way of finely optimizing the luminosity.
10489447
LEP OPERATION AND PERFORMANCE WITH 100 GEV COLLIDING BEAMS
Luminosity production in LEP was extended to 101 GeV beam energy in 1999 and 104.4 GeV in 2000. The performance was continually optimised, resulting in 1999 peak and integrated luminosities higher than in any previous year of LEP operation. In particular, the beambeam tune shift reached 0.083 per interaction point. This was achieved with the help of a faster luminosity monitoring, a new tune working point, a reduced design vertical dispersion and new dispersion and coupling optimisation tools. A higher beam rate from the injectors, a better injection efficiency, a faster ramp and a newly automated control of the horizontal damping partition number J x maximised the time available for physics and thus contributed to the higher integrated luminosity.
17683309
Parasitic energy loss in the LEP superconducting cavities
The energy loss of bunches in the LEP superconducting (SC) cavities has been determined by measuring the closed orbit as a function of current with the beam position monitors located at finite dispersion. This method has already been used in earlier experiments to determine the distribution of the longitudinal impedance of different parts of LEP. In the present experiment the energy loss in two straight sections, containing only SC cavities, was compared with that in sections having both copper cavities and SC cavities. The results confirm the impedance calculations for the two types of cavities. The accuracy of the measurements was considerably improved by determining simultaneously the orbits of bunches with different currents. At the same time with these beam-based impedance measurements, the power dissipation was observed directly by local temperature monitors in different elements: the inter-cavity bellows inside the cryostat, the warm intermodule bellows, and ferrite absorbers which were installed in two places to reduce the energy leaking out of cavities. These observations were correlated with the change of cryogenics power consumption, and showed an unexpected dependence of energy loss on beam energy.
56048929
The BOM 1000 Turn Display : a Tool to Visualize the Transverse Phase-Space Topology at LEP
The LEP BOM 1000 Turn facility enables the User to acquire the position of the beam at each beam position monitor over a number of consecutive turns. By kicking the beam and acquiring the first 1000 turns after the kick, the dynamic behavior of the beam in such a condition can be studied. In particular, by selecting a position monitor and plotting the position of the beam at a given turn against the position shifted by one (or n) turn(s), the evolution of the beam in the phase-space can be observed. Fixed points in the phase-space can be put in evidence, as well as the beam behavior in their neighbourhood. Quantities like the beam damping, or the beam detuning as function of the position amplitude can also be studied in this way. Significant examples from real life will be shown.
119009661
Determination of coupled-lattice properties using turn-by-turn data
A formalism for extracting coupled betatron parameters from multiturn, shock excited, beam position monitor data is described. The most important results are nonperturbative in that they do not rely on the underlying ideal lattice model. Except for damping, which is assumed to be exponential and small enough to be removed empirically, the description is symplectic. As well as simplifying the description, this leads to self-consistency checks that are applied to the data. The most important of these is a {open_quotes}magic ratio{close_quotes} of Fourier coefficients that is required to be a lattice invariant, the same at every beam position monitor. All formulas are applied to both real and simulated data. The real data was acquired June, 1992 at LEP as part of decoupling studies, using the LEP beam orbit measurement system. Simulated data, obtained by numerical tracking (TEAPOT) in the same (except for unknown errors) lattice, agrees well with real data when subjected to identical analysis. For both datasets, deviations between extracted and design parameters and deviations from self-consistency can be accounted for by noise and signal processing limitations. This investigation demonstrates that the LEP beam position system yields reliable local coupling measurements. It can be conservatively assumed that systems of similar design at the SSC and LHC will provide the measurements needed for local decoupling.