Narrow Results

The procedures for the estimation of background and the analytical representation of peak shape are described. The method for the background evaluation is outlined without using peak-free regions in spectrum. The expression for the response function is simple and reproduces experimental data for a wide range of channel numbers and peak positions.

The production of soft e⁺e^- pairs through the interactions of beamstrahlung photons is the major expected background at the next generation of high energy e⁺e^- and e^-e^- colliders. This process has been simulated and the resulting distributions of particles in the very forward 5-25 mrad pair luminosity monitor are shown.

A method for analyzing the structure of the white background in document images is described, along with applications to the problem of isolating blocks of machine-printed text. The approach is based on computational-geometry algorithms for off-line enumeration of maximal white rectangles and on-line rectangle unification. These support a fast, simple, and general heuristic for geometric layout segmentation, in which white space is covered greedily by rectangles until all text blocks are isolated. Design of the heuristic can be substantially automated by an analysis of the empirical statistical distribution of properties of covering rectangles: for example, the stopping rule can be chosen by Rosenblatt’s perceptron training algorithm. Experimental trials show good behavior on the large and useful class of textual Manhattan layouts. On complex layouts from English-language technical journals of many publishers, the method finds good segmentations in a uniform and nearly parameter-free manner. On a variety of non-Latin texts, some with vertical text lines, the method finds good segmentations without prior knowledge of page and text-line orientation.

There are many challenges addressed in MRC compression, such as the segmentation of the document into foreground and background layers, represented as a binary mask. Usually, the resulting quality of a MRC compression method depends on the segmentation algorithm used to compute the binary mask. The aim of this work is to leverage state-of-the-art techniques in document segmentation allowing further content, such as text or images, to be exploited in an efficient way. Then, a novel methodology is proposed that leads to increasing document segmentation performance for MRC compression scheme.

We reexamine the model-independent data analysis methods for extracting properties of Weakly Interacting Massive Particles (WIMPs) by using data (measured recoil energies) from direct Dark Matter detection experiments directly and, as a more realistic study, consider a small fraction of residue background events, which pass all discrimination criteria and then mix with other real WIMP-induced signals in the analyzed data sets. In this talk, the effects of residue backgrounds on the determination of the WIMP mass as well as the spin-independent WIMP coupling on nucleons will be discussed.

Muon induced neutrons and long-lived radioactive isotopes are important background sources for low-energy underground experiments. We study the produced processes and properties of cosmic muon induced backgrounds, show the muon veto system used for rejecting these backgrounds and the methods to estimate residual backgrounds in the Daya Bay Reactor Neutrino Experiment.

Experiments in physics, Astro-particle physics and cosmology that require careful shielding against cosmic rays includes dark matter searches, studies of radioactive decays, and neutrino detection experiments. The need for such shielding has motivated the construction of laboratory caverns in mines and adjacent to tunnels under mountains. There are currently about a dozen such laboratories, in existence or under construction, all in the Northern Hemisphere. There is a well established case put forward for a Southern Hemisphere facility. Presented in this paper is a feasibility study of measurements of radon in air (using electret ion chambers and alpha spectroscopy), background gamma ray measurements (inside/outside) the tunnel using scintillator (inorganic) detectors, cosmic ray measurements using organic scintillators and radiometric analyses of representative rock samples for the establishment of such a facility in the South Africa.

This is a brief introduction of the early history of BES, the formation of BES collaboration. The article is composed by Prof. Zhipeng Zheng, the formal director of IHEP.

A method for analyzing the structure of the white background in document images is described, along with applications to the problem of isolating blocks of machine-printed text. The approach is based on computational-geometry algorithms for offline enumeration of maximal white rectangles and on-line rectangle unification. These support a fast, simple, and general heuristic for geometric layout segmentation, in which white space is covered greedily by rectangles until all text blocks are isolated. Design of the heuristic can be substantially automated by an analysis of the empirical statistical distribution of properties of covering rectangles: for example, the stopping rule can be chosen by Rosenblatt's perceptron training algorithm. Experimental trials show good behavior on the large and useful class of textual Manhattan layouts. On complex layouts from English-language technical journals of many publishers, the method finds good segmentations in a uniform and nearly parameter-free manner. On a variety of non-Latin texts, some with vertical text lines, the method finds good segmentations without prior knowledge of page and text-line orientation.

It is now well established that roughly 25% of the total mass-energy density of the Universe is in the form of non-relativistic particles referred to as Dark Matter. This paper will review various ongoing Dark Matter searches and the variety of techniques and implementation used to both detect the rare Dark Matter interactions as well as reject the vast number of background events, with focus given to the recent results obtained in this past year. Eight years into the 21^st century, the field Dark Matter searches is very active, with many new experimental results, and some intriguing hints.

EDELWEISS-2 is a Ge-bolometer experiment searching for WIMP dark matter and located in the underground laboratory, Laboratoire Souterrain de Modane (LSM, France). The collaboration uses new cryogenic detectors with an improved background rejection (interleaved electrode design and continues further developments. An operation of ten 400-g bolometers at LSM together with an active muon veto shielding has been achieved. Results based on a total effective exposure of 384 kgd obtained in 2009/2010 have been published recently. A cross-section for spin-independent scattering of WIMPs on the nucleon of 4.4·10⁻⁸ pb is excluded at 90%CL for a WIMP mass of 85 GeV. This bolometer data and the latest measurements with 800-g detectors are presented. Further plans of the collaboration to reach sensitivity of 5 · 10⁻⁹pb and for a next generation experiment, EURECA, are discussed.