Symmetries and conservation laws have both played a vital part in the development of the Standard Model in the 20 century, and discoveries of symmetry violations have helped to propel elementary particle physics forward to the theory we have today. In this essay I attempt to introduce both the historical and theoretical background to this most important concept in particle physics, as well as g...

We have carried out a direct search in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied-about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0. 16e ( e ...

These proceedings summarize lectures that were delivered as part of the 2002 and 2003 Theoretical Advanced Study Institutes in elementary particle physics (TASI) at the University of Colorado at Boulder. They are intended to provide a pedagogical introduction to cosmology aimed at advanced graduate students in particle physics and string theory.

An InSb Schottky detector, fabricated from an undoped InSb wafer with Hall mobility which is higher than those of previously employed InSb wafers, was used for alpha particle detection. The output pulse of this InSb detector showed a very fast rise time, which was comparable with the output pulses of scintillation detectors.

The single-period problem (SPP), also known as the newsboy or news-vendor problem, is to ®nd the order quantity which maximizes the expected pro®t in a single period probabilistic demand framework. Interest in the SPP remains unabated and many extensions to it have been proposed in the last decade. These extensions include dealing with di€erent objectives and utility functions, di€erent supplie...

** The research reported in this paper was partially supported by grants from the U.S. Department of Education to the Consortium for Policy Research in Education (Grant # OERI-R308A60003), the National Science Foundation’s Interagency Educational Research Initiative (Grant # REC 9979863), and the Atlantic Philanthropies. Opinions expressed in this paper are those of the author, and do not neces...

The purpose of the paper is twofold. I first outline a philosophical theory of concepts based on conceptual role semantics. This approach is explicitly intended as a framework for the study and explanation of conceptual change in science. Then I point to the close similarities between this philosophical framework and the theory theory of concepts, suggesting that a convergence between psycholog...

The details of what constitutes the majority of the mass that makes up dark matter in the Universe remains one of the prime puzzles of cosmology and particle physics today-80 y after the first observational indications. Today, it is widely accepted that dark matter exists and that it is very likely composed of elementary particles, which are weakly interacting and massive [weakly interacting ma...