Photon Multiplicity Measurements : From SPS to RHIC and LHC

Results from the photon multiplicity measurements using a fine granularity preshower photon multiplicity detector (PMD) at CERN SPS are discussed. These include study of pseudo-rapidity distributions of photons, scaling of photon multiplicity with number of participating nucleons, centrality dependence of mean transverse momentum of photons, event-by-event fluctuations in photon multiplicity and localised charged-neutral fluctuations. Basic features of the PMD to be used in STAR experiment at RHIC and in ALICE experiment at LHC are also discussed.Comment: 12 pages, Invited talk at the 4th International Conference on the Physcis and Astrophysics of the Quark-Gluon-Plasma, November 2001, Jaipur, India, to appear in Praman

On the stability constraints and oscillatory behavior of coupled systems

Stability constraints for two general forms of coupled systems of second order nonlinear differential equation

Flow with PMD: Past and Future

Measurements of azimuthal distribution of inclusive photons using the fine granularity preshower photon multiplicity detector (PMD) at CERN SPS are used to obtain anisotropy in the azimuthal distributions. These results are used to estimate the anisotropy in the neutral pion distributions. The results are compared with results of charged particle data, both for first order and second order anisotropy. Assuming the same anisotropy for charged and neutral pions, the anisotropy in photons is estimated and compared with the measured anisotropy. The effect of neutral pion decay on the correlation between the first order and the second order event plane is also discussed. Data from PMD can also be used to estimate the reaction plane for studying any anisotropy in particle emission characteristics in the ALICE experiment at the Large Hadron Collider. In particular, we show that using the event plane from the PMD, it will be possible to measure the anisotropy in Jpsi absorption (if any) in the ALICE experiment.Comment: Invited talk in the Fourth International Conference on the Physics and Astrophysics of Quark Gluon Plasma, 26-30 Nov.2001, Jaipur, Indi

Optimal control of linear time delay systems

Obtaining optimal control for linear time varying system with time dela

Event-by-Event Search for Charged Neutral Fluctuations in Pb - Pb Collisions at 158-A-GeV

Results from the analysis of data obtained from the WA98 experiment at the CERN SPS have been presented. Some events have been filtered which show photon excess in limited $\eta-\phi$ zones within the overlap region of the charged particle and photon multiplicity detectors.Comment: 6 pages, 4 figure

Studies in matter antimatter separation and in the origin of lunar magnetism

Antimatter experiments of the University of Santa Clara are investigated. Topics reported include: (1) planetary geology, (2) lunar Apollo magnetometer experiments, and (3) Roche limit of a solid body

Comparative studies of lunar, Martian, and Mercurian craters and plains

The spatial distribution of lunar smooth plains is not consistent with experimental simulations of melt rock emplacement during cratering in layered materials. Nor is it consistent with the location of melt rocks (suevite) near the Ries basin. Lunar smooth plains surrounding Imbrium are most extensive in areas where pre-existing craters are most degraded. This observation suggests that plains form by impact of basin and local primary crater ejecta, together with deposition of debris excavated by the resultant secondary cratering events. Craters within the belt of smooth plains surrounding the Caloris basin on Mercury are most degraded nearest the basin; this suggests that Mercurian smooth plains must, at least in part, be emplaced in a manner similar to plains surrounding the Imbrium basin. Mercurian uplands have a primary crater population deficient in small crater diameters (less than approximately 30 km). Lunar uplands far from major basins also have a crater population deficient in small crater sizes. Martian cratered terrain exhibits a similar crater deficiency, which was previously interpreted as due to obliteration of small craters (less than approximately 30 km) by some surface process. A crater size distribution deficient in small sizes (less than approximately 30 km) on the Mercurian, lunar, and Martian uplands has implications for the origin of debris bombarding the inner solar system during the period recorded by these surfaces. It is proposed that during late heavy bombardment, the inner solar system was inundated with bodies that broke up under tidal fission as they approached the planets. Such a mechanism would lend to production of a crater population deficient in small crater sizes, and it would also explain the large degree of spatial clustering of primary craters on Mercury, the moon, and Mars

Change detection in categorical evolving data streams

Detecting change in evolving data streams is a central issue for accurate adaptive learning. In real world applications, data streams have categorical features, and changes induced in the data distribution of these categorical features have not been considered extensively so far. Previous work on change detection focused on detecting changes in the accuracy of the learners, but without considering changes in the data distribution. To cope with these issues, we propose a new unsupervised change detection method, called CDCStream (Change Detection in Categorical Data Streams), well suited for categorical data streams. The proposed method is able to detect changes in a batch incremental scenario. It is based on the two following characteristics: (i) a summarization strategy is proposed to compress the actual batch by extracting a descriptive summary and (ii) a new segmentation algorithm is proposed to highlight changes and issue warnings for a data stream. To evaluate our proposal we employ it in a learning task over real world data and we compare its results with state of the art methods. We also report qualitative evaluation in order to show the behavior of CDCStream

On fixed linear systems with a generalized performance criteria

Fixed linear systems with generalized performance criteri