122670209
First coincidence search among periodic gravitational wave source candidates using Virgo data
F. Acernese6, P. Amico10, M. Alshourbagy11, F. Antonucci 12, S. Aoudia7, P. Astone12, S. Avino6, D. Babusci4, G. Ballardin2, F. Barone6, L. Barsotti11, M. Barsuglia8 , F. Beauville1, S. Bigotta11, S. Birindelli11, M.A. Bizouard8, C. Boccara9, F. Bondu7, L. Bosi10, C. Bradaschia11, S. Braccini11,A. Brillet7, V. Brisson8, L. Brocco12, D. Buskulic1, E. Calloni6, E. Campagna3, F. Carbognani2, F. Cavalier8, R. Cavalieri2, G. Cella11, E. Cesarini3, E. Chassande-Mottin7, N. Christensen2, C. Corda11, A. Corsi12, F. Cottone10, A.-C. Clapson8, F. Cleva7, J.-P. Coulon7, E. Cuoco2, A. Dari10, V. Dattilo2, M. Davier8, M. del Prete2, R. De Rosa6, L. Di Fiore6, A. Di Virgilio11, B. Dujardin7, A. Eleuteri6, I. Ferrante11, F. Fidecaro11, I. Fiori11, R. Flaminio1, 2, J.-D. Fournier7, O.Francois2, S. Frasca12, F. Frasconi2, 11, L. Gammaitoni10, F. Garufi6, E. Genin2, A. Gennai11, A. Giazotto11, G. Giordano4, L. Giordano6, R. Gouaty1, D. Grosjean1, G. Guidi3, S. Hebri2, H. Heitmann7, P. Hello8, S. Karkar1, S. Kreckelbergh8, P. La Penna2, M. Laval7, N. Leroy8, N. Letendre1, B. Lopez2, Lorenzini3, V. Loriette9, G. Losurdo3, J.-M. Mackowski5, E. Majorana12, C. N. Man7, M. Mantovani11, F. Marchesoni10, F. Marion1, J. Marque2, F. Martelli3, A. Masserot1, M. Mazzoni3, L. Milano6, F. Menzinger2, C. Moins2, J. Moreau9, N. Morgado5, B. Mours1, F. Nocera2, A. Pai12, C. Palomba12, F. Paoletti2, 11, S. Pardi6, A. Pasqualetti2, R. Passaquieti11, D. Passuello11, B. Perniola3, F. Piergiovanni3, L. Pinard5, R. Poggiani11, M. Punturo10, P. Puppo12, K. Qipiani6, P. Rapagnani12, V. Reita9, A. Remillieux5, F. Ricci12, I. Ricciardi6, P. Ruggi 2, G. Russo6, S. Solimeno6, A. Spallicci7, R. Stanga3, T. Marco11, M. Tonelli11, A. Toncelli11, E. Tournefier1, F. Travasso10, C. Tremola11, G. Vajente 11, D. Verkindt1, F. Vetrano3, A. Vicere3, J.-Y. Vinet7, H. Vocca10 and M. Yvert1 1Laboratoire d’Annecy-le-Vieux de Physique des Particules (LAPP), IN2P3/CNRS, Universite de Savoie, Annecy-le-Vieux, France;
122598875
RESULTS FROM LIGO OBSERVATIONS: STOCHASTIC BACKGROUND AND CONTINUOUS WAVE SIGNALS
The search for gravitational radiation has entered a new era as the Laser Interferom-eter Gravitational Wave Observatory (LIGO) has reached its initial target sensitivity. Other similar interferometric detectors are also approaching their design goals. There is presently vigorous activity in the gravitational radiation community in the search for signals. Here we review the status of the LIGO search for a stochastic background, and continuous wave signals.
15022161
A first comparison of search methods for gravitational wave bursts using LIGO and Virgo simulated data
We present a comparative study of six search methods for gravitational wave bursts using simulated LIGO and Virgo noise data. The simulated data were generated according to the design sensitivity of the two 4 km LIGO interferometers and the 3 km Virgo interferometer. The searches were applied on replicas of the data sets to which eight different signals were injected. Three figures of merit were employed in this analysis: (a) receiver operator characteristic curves, (b) necessary signal-to-noise ratios for the searches to achieve 50% and 90% efficiencies and (c) variance and bias for the estimation of the arrival time of a gravitational wave burst.
2702261
LISA source confusion: identification and characterization of signals
The Laser Interferometer Space Antenna (LISA) is expected to detect gravitational radiation from a large number of compact binary systems. We present a method by which these signals can be identified and have their parameters estimated. Our approach uses Bayesian inference, specifically the application of a Markov chain Monte Carlo method. The simulation study that we present here considers a large number of sinusoidal signals in noise, and our method estimates the number of periodic signals present in the data, the parameters for these signals and the noise level. The method is significantly better than classical spectral techniques at performing these tasks and does not use stopping criteria for estimating the number of signals present.
13085972
Using Markov chain Monte Carlo methods for estimating parameters with gravitational radiation data
We present a Bayesian approach to the problem of determining parameters for coalescing binary systems observed with laser interferometric detectors. By applying a Markov Chain Monte Carlo (MCMC) algorithm, specifically the Gibbs sampler, we demonstrate the potential that MCMC techniques may hold for the computation of posterior distributions of parameters of the binary system that created the gravity radiation signal. We describe the use of the Gibbs sampler method, and present examples whereby signals are detected and analyzed from within noisy data.
43905547
Veto studies for LIGO inspiral triggers
LIGO recently conducted its third scientific data run, S3. Here, we summarize the veto and data quality studies conducted by the LIGO Scientific Collaboration in connection with the search for binary inspiral signals in the S3 data. The veto results presented here come from studies on the S3 playground data. LIGO's interferometer channels and physical environmental monitors were monitored, and events in these channels coincident with inspiral triggers were examined.
119230543
Pair production of MSSM Higgs bosons in the nondecoupling region at the LHC
We consider the Higgs boson signals from pair production at the LHC within the framework of the MSSM in the non-decoupling (low-m_A) region. In light of the recent observation of a SM-like Higgs boson, we argue that the exploration for Higgs pair production at the LHC is a crucial next step to probe the MSSM Higgs sector. We emphasize that the production of H^\pm A^0 and H^{+}H^{-} depends only on the electroweak gauge couplings while all the leading Higgs production channels via gluon fusion, vector-boson fusion, and Higgsstrahlung depend on additional free Higgs sector parameters. In the non-decoupling region, the five MSSM Higgs bosons are all relatively light and pair production signals may be accessible. We find that at the 8 TeV LHC, a 5\sigma signal for H^\pm A^0, H^\pm h^0 -> \tau^{\pm}\nu b\bar b and H^{+}H^{-} -> \tau^{+}\nu \tau^{-}\nu are achievable with an integrated luminosity of 7 (11) fb^{-1} and 24 (48) fb^{-1}, respectively for m_A=95 (130) GeV. At the 14 TeV LHC, a 5\sigma signal for these two channels would require as little as 4 (7) fb^{-1} and 10 (19) fb^{-1}, respectively.
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.
51806520
New developments in FEYNRULES
The program FeynRules is a Mathematica package developed to facilitate the implementation of new physics theories into high-energy physics tools. Starting from a minimal set of information such as the model gauge symmetries, its particle content, parameters and Lagrangian, FeynRules provides all necessary routines to extract automatically from the Lagrangian (that can also be computed semi-automatically for supersymmetric theories) the associated Feynman rules. These can be further exported to several Monte Carlo event generators through dedicated interfaces, as well as translated into a Python library, under the so-called UFO model format, agnostic of the model complexity, especially in terms of Lorentz and/or color structures appearing in the vertices or of number of external legs. In this work, we briefly report on the most recent new features that have been added to FeynRules, including full support for spin- 3 fermions, a new module allowing for the automated diagonalization of the particle spectrum and a new set of routines dedicated to decay width calculations.
119517996
Extended technicolor models with two ETC groups
We construct extended technicolor (ETC) models that can produce the large splitting between the masses of the $t$ and $b$ quarks without necessarily excessive contributions to the $\rho$ parameter or to neutral flavor-changing processes. These models make use of two different ETC gauge groups, such that left- and right-handed components of charge $Q=2/3$ quarks transform under the same ETC group, while left- and right-handed components of charge -1/3 quarks and charged leptons transform under different ETC groups. The models thereby suppress the masses $m_b$ and $m_\tau$ relative to $m_t$, and $m_s$ and $m_\mu$ relative to $m_c$ because the masses of the $Q=-1/3$ quarks and charged leptons require mixing between the two ETC groups, while the masses of the $Q=2/3$ quarks do not. A related source of the differences between these mass splittings is the effect of the two hierarchies of breaking scales of the two ETC groups. We analyze a particular model of this type in some detail. Although we find that this model tends to suppress the masses of the first two generations of down-type quarks and charged leptons too much, it gives useful insights into the properties of theories with more than one ETC group.
119069146
Flavor-changing processes in extended technicolor
We analyze constraints on a class of extended technicolor (ETC) models from neutral flavor-changing processes induced by (dimension-six) four-fermion operators. The ETC gauge group is taken to commute with the standard model gauge group. The models in the class are distinguished by how the left- and right-handed $(L,R)$ components of the quarks and charged leptons transform under the ETC group. We consider ${K}^{0}\ensuremath{-}{\overline{K}}^{0}$ and other pseudoscalar meson mixings, and conclude that they are adequately suppressed if the $L$ and $R$ components of the relevant quarks are assigned to the same (fundamental or conjugate-fundamental) representation of the ETC group. Models in which the $L$ and $R$ components of the down-type quarks are assigned to relatively conjugate representations, while they can lead to realistic CKM mixing and intrafamily mass splittings, do not adequately suppress these mixing processes. We identify an approximate global symmetry that elucidates these behavioral differences and can be used to analyze other possible representation assignments. Flavor-changing decays, involving quarks and/or leptons, are adequately suppressed for any ETC representation assignment of the $L$ and $R$ components of the quarks, as well as the leptons. We draw lessons for future ETC model building.