1,213 research outputs found
Synchronization of the CMS muon detector
Precise synchronization is crucial for the functioning of the CMS Muon Detector. In this paper we first discuss the possible sources of data misalignment, like variations in particle time of flight, signal formation and propagation within a detector ( e.g. drift time), connections between various elements, set-up times and jitters of digital electronics. Then we review several methods which can be used to synchronize the system for the first time and to maintain the synchronization over a long period of time. Finally we discuss in detail a possible application of those methods to the Resistive Plate Chambers. We also briefly discuss the cases of Drift Tubes and Cathode Strip Chambers
Discovering New Particles at Colliders
We summarize the activities of the New Particles Subgroup at the 1996 Snowmass Workshop. We present the expectations for discovery or exclusion of leptoquarks at hadron and lepton colliders in the pair production and single production modes. The indirect detection of a scalar lepton quark at polarized and colliders is discussed. The discovery prospects for particles with two units of lepton number is discussed. We summarize the analysis of the single production of neutral heavy leptons at lepton colliders
Discovery Potential for New Phenomena
We examine the ability of future facilities to discover and interpret non-supersymmetric new phenomena. We first explore explicit manifestations of new physics, including extended gauge sectors, leptoquarks, exotic fermions, and technicolor models. We then take a more general approach where new physics only reveals itself through the existence of effective interactions at lower energy scales. [Summary Report of the New Phenomena Working Group. To appear in the Proceedings of the 1996 DPF/DPB Summer Study on New Directions for High Energy Physics - Snowmass96, Snowmass, CO, 25 June - 12 July 1996.
Applications of Free Electron Lasers in Biology and Medicine
The advent of free electron lasers opens up new opportunities to probe the dynamics of ultrafast processes and the structure of matter with unprecedented spatial and temporal resolution. New methods inaccessible with other known types of radiation sources can be developed, resulting in a breakthrough in deep understanding the fundamentals of life as well as in numerous medical and biological applications. In the present work the properties of free electron laser radiation that make the sources excellent for probing biological matter at an arbitrary wavelength, in a wide range of intensities and pulse durations are briefly discussed. A number of biophysical and biomedical applications of the new sources, currently considered among the most promising in the field, are presented
The catalog of short periods stars from the ''Pi of the Sky'' data
Based on the data from the ''Pi of the Sky'' project we made a catalog of the
variable stars with periods from 0.1 to 10 days. We used data collected during
a period of two years (2004 and 2005) and classified 725 variable stars. Most
of the stars in our catalog are eclipsing binaries - 464 (about 64%), while the
number of pulsating stars is 125 (about 17%). Our classification is based on
the shape of the light curve, as in the GCVS catalog. However, some stars in
our catalog were classified as of different type than in the GCVS catalog. We
have found periods for 15 stars present in the GCVS catalog with previously
unknown period.Comment: New Astronomy in prin
The Gravitino-Stau Scenario after Catalyzed BBN
We consider the impact of Catalyzed Big Bang Nucleosynthesis on theories with
a gravitino LSP and a charged slepton NLSP. In models where the gravitino to
gaugino mass ratio is bounded from below, such as gaugino-mediated SUSY
breaking, we derive a lower bound on the gaugino mass parameter m_1/2. As a
concrete example, we determine the parameter space of gaugino mediation that is
compatible with all cosmological constraints.Comment: 1+14 pages, 6 figures; v2: minor clarifications, 1 reference added,
matches version to appear in JCA
GRB 080319B: A Naked-Eye Stellar Blast from the Distant Universe
Long duration gamma-ray bursts (GRBs) release copious amounts of energy
across the entire electromagnetic spectrum, and so provide a window into the
process of black hole formation from the collapse of a massive star. Over the
last forty years, our understanding of the GRB phenomenon has progressed
dramatically; nevertheless, fortuitous circumstances occasionally arise that
provide access to a regime not yet probed. GRB 080319B presented such an
opportunity, with extraordinarily bright prompt optical emission that peaked at
a visual magnitude of 5.3, making it briefly visible with the naked eye. It was
captured in exquisite detail by wide-field telescopes, imaging the burst
location from before the time of the explosion. The combination of these unique
optical data with simultaneous gamma-ray observations provides powerful
diagnostics of the detailed physics of this explosion within seconds of its
formation. Here we show that the prompt optical and gamma-ray emissions from
this event likely arise from different spectral components within the same
physical region located at a large distance from the source, implying an
extremely relativistic outflow. The chromatic behaviour of the broadband
afterglow is consistent with viewing the GRB down the very narrow inner core of
a two-component jet that is expanding into a wind-like environment consistent
with the massive star origin of long GRBs. These circumstances can explain the
extreme properties of this GRB.Comment: 43 pages, 18 figures, 3 tables, submitted to Nature May 11, 200
Parallax in “Pi of the Sky” project
The main goal of the “Pi of the Sky” project is search for optical transients (OTs) of astrophysical origin, in particular those related to gamma-ray bursts (GRBs). Since March 2011 the project has two running observatories: one in northern Chile and the other one insouthern Spain. This allows for regular observations of a common sky fields, visible from both observatories which are scheduled usually 1–2 h per night. In such a case, the on-line flash recognition algorithm, looking for optical transients, can use parallax information toassure that events observed from both sites have parallax angle smaller than the error of astrometry. On the other hand, the remaining OT candidates can be verified against a hypothesis of being near-Earth objects. This paper presents algorithm using parallax information for identification of near-Earth objects, which might be satellites, or space debris elements. Preliminary results of the algorithm are also presented
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