206997636
CalcHEP 3.4 for collider physics within and beyond the Standard Model
We present version 3.4 of the CalcHEP software package which is designed for effective evaluation and simulation of high energy physics collider processes at parton level. The main features of CalcHEP are the computation of Feynman diagrams, integration over multi-particle phase space and event simulation at parton level. The principle attractive key-points along these lines are that it has: (a) an easy startup and usage even for those who are not familiar with CalcHEP and programming; (b) a friendly and convenient graphical user interface (GUI); (c) the option for the user to easily modify a model or introduce a new model by either using the graphical interface or by using an external package with the possibility of cross checking the results in different gauges; (d) a batch interface which allows to perform very complicated and tedious calculations connecting production and decay modes for processes with many particles in the final state. With this features set, CalcHEP can efficiently perform calculations with a high level of automation from a theory in the form of a Lagrangian down to phenomenology in the form of cross sections, parton level event simulation and various kinematical distributions. In this paper we report on the new features of CalcHEP 3.4 which improves the power of our package to be an effective tool for the study of modern collider phenomenology
118658638
Top triangle moose: Combining Higgsless and topcolor mechanisms for mass generation
We present the details of a deconstructed model that incorporates both Higgsless and top-color mechanisms. The model alleviates the tension between obtaining the correct top quark mass and keeping {delta}{rho} small that exists in many Higgsless models. It does so by singling out the top quark mass generation as arising from a Yukawa coupling to an effective top Higgs which develops a small vacuum expectation value, while electroweak symmetry breaking results largely from a Higgsless mechanism. As a result, the heavy partners of the SM fermions can be light enough to be seen at the LHC. After presenting the model, we detail the phenomenology, showing that for a broad range of masses, these heavy fermions are discoverable at the LHC.
119346782
Technifermion representations and precision electroweak constraints
Abstract We discuss the selection of fermion representations in technicolor models with a view toward minimizing technicolor contributions to the precision electroweak S parameter. We present and analyze models that involve one technifermion SU ( 2 ) L doublet with standard-model singlet technifermion sectors that lead to walking behavior, which further reduces S. We also consider models that have technifermions in higher-dimensional representations and study embeddings in extended technicolor theories.
26080010
LIGO S6 detector characterization studies
LIGO recently commenced its sixth science run (S6) simultaneously with Virgo starting its second science run (VSR2). Because of differing interferometer configurations with respect to S5, much effort has been invested understanding new sources of noise in the LIGO S6 interferometers. The LIGO Scientific Collaboration's detector characterization working group is actively investigating the origin of noise in the LIGO interferometers and determining the periods of good, bad or questionable data quality. We describe the instrumental issues found to affect the data quality in S6 and the vetoes developed for burst and inspiral searches. The methods used to search for and identify periodic noise lines are also presented. A summary of other noise search efforts in S6 is also given.
988568
Gravitational-wave astronomy with inspiral signals of spinning compact-object binaries
Inspiral signals from binary compact objects (black holes and neutron stars) are primary targets of the ongoing searches by ground-based gravitational-wave interferometers (LIGO, Virgo, and GEO-600). We present parameter-estimation simulations for inspirals of black hole-neutron star binaries using Markov Chain Monte Carlo methods. For the first time, we both estimated the parameters of a binary inspiral source with a spinning, precessing component and determined the accuracy of the parameter estimation, for simulated observations with ground-based gravitational-wave detectors. We demonstrate that we can obtain the distance, sky position, and binary orientation at a higher accuracy than previously suggested in the literature. For an observation of an inspiral with sufficient spin and two or three detectors we find an accuracy in the determination of the sky position of the order of tens of square degrees.
121103964
Methods of gravitational wave detection in the VIRGO Interferometer
The gravitational wave detector VIRGO is in the final commissioning phase and some preliminary data has already been acquired. The aim of VIRGO is to directly detect gravitational waves emitted by compact objects at the time of coalescence and by other astrophysical sources. Here we report on the present sensitivity for detecting these sources and what we will achieve in the near future. We also discuss some details of our data analysis methods and we show some preliminary results related to the fraction of the Universe that we can observe.
9176350
Inference on inspiral signals using LISA MLDC data
In this paper, we describe a Bayesian inference framework for the analysis of data obtained by LISA. We set up a model for binary inspiral signals as defined for the Mock LISA Data Challenge 1.2 (MLDC), and implemented a Markov chain Monte Carlo (MCMC) algorithm to facilitate exploration and integration of the posterior distribution over the nine-dimensional parameter space. Here, we present intermediate results showing how, using this method, information about the nine parameters can be extracted from the data.
2694758
Bayesian inference on compact binary inspiral gravitational radiation signals in interferometric data
In this paper we present a description of a Bayesian analysis framework for use with interferometric gravitational radiation data in search of binary neutron star inspiral signals. Five parameters are investigated, and the information extracted from the data is illustrated and quantified. The posterior integration is carried out using Markov chain Monte Carlo (MCMC) methods. Implementation details include the use of importance resampling for improved convergence and informative priors reflecting the conditions expected for realistic measurements. An example is presented from an application using realistic, albeit fictitious, data. We expect that these parameter estimation techniques will prove useful at the end of a binary inspiral detection pipeline for interferometric detectors like LIGO or Virgo.