5,146 research outputs found
Do Young Neutron Stars Which Show Themselves As AXPs, SGRs and Radio Pulsars Accrete?
We examined the fall-back disk models, and in general accretion, proposed to
explain the properties of anomalous X-ray pulsars (AXPs), soft gamma repeaters
(SGRs), and radio pulsars (PSRs). We checked the possibility of some gas
remaining around the neutron star after the supernova explosion. We also
compared AXPs and SGRs with the X-ray pulsars in X-ray binaries. We conclude
the existing models of accretion from a fall-back disk are insufficient to
explain the nature of AXPs/SGRs, particularly the SGR bursts. We also discussed
the proposed model of combination of magnetic dipole radiation and propeller
torques in order to explain the evolution of radio pulsars on the P-\.{P}
diagram. The predictions of this model contradict the observational data.Comment: 16 Pages, 1 Figur
Electricity Trade Patterns in a Network: Evidence from the Ontario Market
We investigate whether trade has any effect on the price formation process in a specific electricity market, and identify interconnected markets that have higher impacts on prices in that market. In particular, we study Ontario wholesale electricity market and its trade with 12 interconnected markets including New York, Michigan, and Minnesota markets. We find that imports are unambiguously related to prices, while exports are not. Furthermore, imports have a positive and significant relationship with prices. We argue that the results are associated with auction design, production constraints, and technological differences. Out of the 12 studied interties, only three have a significant impact on price, two of which are the largest ones.electricity trade; simultaneous trade; transmission network; electricity prices; nonlinear Granger causality; Ontario, New York, Michigan, Manitoba, Quebec wholesale electricity markets.
Search for a Standard Model Higgs Boson in CMS via Vector Boson Fusion in the H->WW->l\nu l\nu Channel
We present the potential for discovering the Standard Model Higgs boson
produced by the vector-boson fusion mechanism. We considered the decay of Higgs
bosons into the W+W- final state, with both W-bosons subsequently decaying
leptonically. The main background is ttbar with one or more jets produced. This
study is based on a full simulation of the CMS detector, and up-to-date
reconstruction codes. The result is that a signal of 5 sigma significance can
be obtained with an integrated luminosity of 12-72 1/fb for Higgs boson masses
between 130-200 GeV. In addition, the major background can be measured directly
to 7% from the data with an integrated luminosity of 30 1/fb. In this study, we
also suggested a method to obtain information in Higgs mass using the
transverse mass distributions.Comment: 26 pages, 22 figure
A practical probabilistic earthquake hazard analysis tool: case study Marmara region
Earthquakes have a damaging impact on the economic welfare and resilience of communities, particularly in developing countries. Seismic hazard assessment is the first step towards performing prevention, preparedness, and response or recovery actions to reduce seismic risk. This paper presents a computation tool for predicting the seismic hazard at the macro level as a part of a comprehensive multi-hazard framework on earthquake risk assessment. The probabilistic seismic hazard analysis (PSHA) procedure is based on the Monte-Carlo approach, and particular attention is paid to the definition of source zones assigned in the study area. Both Poisson and time dependent (renewal) models are adopted to quantify the effect of temporal dependencies between seismic events, while near-field rupture directivity effects are also taken into account. Marmara region in Turkey is selected as a case study area to perform a new seismic hazard analysis and verify the accuracy of the proposed tool. The results show good agreement with results from the recent SHARE project and the latest Turkish Earthquake Design code hazard maps. This confirms that the proposed PSHA method can be an attractive alternative to the direct integration based methods due to its practicality and powerful handling of uncertainties
Simulation of the CMS Resistive Plate Chambers
The Resistive Plate Chamber (RPC) muon subsystem contributes significantly to
the formation of the trigger decision and reconstruction of the muon trajectory
parameters. Simulation of the RPC response is a crucial part of the entire CMS
Monte Carlo software and directly influences the final physical results. An
algorithm based on the parametrization of RPC efficiency, noise, cluster size
and timing for every strip has been developed. Experimental data obtained from
cosmic and proton-proton collisions at TeV have been used for
determination of the parameters. A dedicated validation procedure has been
developed. A good agreement between the simulated and experimental data has
been achieved.Comment: to be published in JINS
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Measurement of masses in the [Formula: see text] system by kinematic endpoints in pp collisions at [Formula: see text].
A simultaneous measurement of the top-quark, W-boson, and neutrino masses is reported for [Formula: see text] events selected in the dilepton final state from a data sample corresponding to an integrated luminosity of 5.0 fb-1 collected by the CMS experiment in pp collisions at [Formula: see text]. The analysis is based on endpoint determinations in kinematic distributions. When the neutrino and W-boson masses are constrained to their world-average values, a top-quark mass value of [Formula: see text] is obtained. When such constraints are not used, the three particle masses are obtained in a simultaneous fit. In this unconstrained mode the study serves as a test of mass determination methods that may be used in beyond standard model physics scenarios where several masses in a decay chain may be unknown and undetected particles lead to underconstrained kinematics
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