0000000000549504
AUTHOR
G Mitselmakher
Search for Multimessenger Sources of Gravitational Waves and High-energy Neutrinos with Advanced LIGO during Its First Observing Run, ANTARES, and IceCube
[EN] Astrophysical sources of gravitational waves, such as binary neutron star and black hole mergers or core-collapse supernovae, can drive relativistic outflows, giving rise to non-thermal high-energy emission. High-energy neutrinos are signatures of such outflows. The detection of gravitational waves and high-energy neutrinos from common sources could help establish the connection between the dynamics of the progenitor and the properties of the out¿ow. We searched for associated emission of gravitational waves and high-energy neutrinos from astrophysical transients with minimal assumptions using data from Advanced LIGO from its first observing run O1, and data from the ANTARES and IceCub…
Measurements of the Lineshape of the $Z^{0}$ and Determination of Electroweak Parameters from its Hadronic and Leptonic Decays
Abstract: During the LEP running periods in 1990 and 1991 DELPHI has accumulated approximately 450000 Z0 decays into hadrons and charged leptons. The increased event statistics coupled with improved analysis techniques and improved knowledge of the LEP beam energies permit significantly better measurements of the mass and width of the Z0 resonance. Model independent fits to the cross sections and leptonic forward-backward asymmetries yield the following Z0 parameters: the mass and total width M(Z) = 91.187 +/- 0.009 GeV, GAMMA(Z) = 2.486 +/- 0.012 GeV, the hadronic and leptonic partial widths GAMMA(had) = 1.725 +/- 0.012GeV, GAMMA(l) = 83.01 +/- 0.52 MeV, the invisible width GAMMA(inv) = 51…
Search for High-energy Neutrinos from Gravitational Wave Event GW151226 and Candidate LVT151012 with ANTARES and IceCube
[EN] The Advanced LIGO observatories detected gravitational waves from two binary black hole mergers during their first observation run (O1). We present a high-energy neutrino follow-up search for the second gravitational wave event, GW151226, as well as for gravitational wave candidate LVT151012. We find two and four neutrino candidates detected by IceCube, and one and zero detected by ANTARES, within +/- 500 s around the respective gravitational wave signals, consistent with the expected background rate. None of these neutrino candidates are found to be directionally coincident with GW151226 or LVT151012. We use nondetection to constrain isotropic-equivalent high-energy neutrino emission …
Properties of the Binary Neutron Star Merger GW170817
On August 17, 2017, the Advanced LIGO and Advanced Virgo gravitational-wave detectors observed a low-mass compact binary inspiral. The initial sky localization of the source of the gravitational-wave signal, GW170817, allowed electromagnetic observatories to identify NGC 4993 as the host galaxy. In this work, we improve initial estimates of the binary's properties, including component masses, spins, and tidal parameters, using the known source location, improved modeling, and recalibrated Virgo data. We extend the range of gravitational-wave frequencies considered down to 23 Hz, compared to 30 Hz in the initial analysis. We also compare results inferred using several signal models, which ar…
DETERMINATION OF ALPHA(S) FOR B-QUARKS AT THE Z(0) RESONANCE
The strong coupling constant for b quarks has been determined, and its flavour independence, as predicted by QCD, investigated. The analysis involved events with lepton candidates selected from approximately 356 000 hadronic decays of the Z0, collected by the DELPHI detector at LEP in 1990 and 199 1. A method based on a direct comparison of the three-jet fraction in a b enriched sample, selected by requiring leptons with large momenta and transverse momenta, to that of the entire hadronic sample, illustrated the significant effect of the b quark mass on the multi-jet cross section, and verified the flavour independence of the strong coupling constant to an accuracy of +/- 6%. A second proce…
DETERMINATION OF ALPHA-S FROM THE SCALING VIOLATION IN THE FRAGMENTATION FUNCTIONS IN E+E- ANNIHILATION
A determination of the hadronic fragmentation functions of the Z0 boson is presented from a study of the inclusive hadron production with the DELPHI detector at LEP. These fragmentation functions were compared with the ones at lower energies, thus covering data in a large kinematic range: 196 less-than-or-equal-to Q2 less-than-or-equal-to 8312 GeV2 and x (= p(h)/E(beam)) > 0.08. A large scaling violation was observed, which was used to extract the strong coupling constant in second order QCD: alpha(s)(M(Z)) = 0.118 +/- 0.005. The corresponding QCD scale for five quark flavours is: LAMBDA(MS)(5)BAR = 230 +/- 60 MeV.
Search for eccentric binary black hole mergers with advanced LIGO and advanced Virgo during their first and second observing runs
When formed through dynamical interactions, stellar-mass binary black holes may retain eccentric orbits ($e>0.1$ at 10 Hz) detectable by ground-based gravitational-wave detectors. Eccentricity can therefore be used to differentiate dynamically-formed binaries from isolated binary black hole mergers. Current template-based gravitational-wave searches do not use waveform models associated to eccentric orbits, rendering the search less efficient to eccentric binary systems. Here we present results of a search for binary black hole mergers that inspiral in eccentric orbits using data from the first and second observing runs (O1 and O2) of Advanced LIGO and Advanced Virgo. The search uses min…
Search for Subsolar Mass Ultracompact Binaries in Advanced LIGO's Second Observing Run
We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO’s second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between \ud0.2\ud \ud \udM\ud⊙\ud–\ud1.0\ud \ud \udM\ud⊙\ud. We use the null result to constrain the binary merger rate of (\ud0.2\ud \ud \udM\ud⊙\ud, \ud0.2\ud \ud \udM\ud⊙\ud) binaries to be less than \ud3.7\ud×\ud10\ud5\ud \ud \udGpc\ud−\ud3\ud \udyr\ud−\ud1\udand the binary …
Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A
On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB 170817A was observed independently by the Fermi Gamma-ray Burst Monitor, and the Anticoincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory. The probability of the near-simultaneous temporal and spatial observation of GRB 170817A and GW170817 occurring by chance is $5.0\times 10^{-8}$. We therefore confirm binary neutron star mergers as a progenitor of short GRBs. The association of GW170817 and GRB 170817A provides new insight into fundamental physics and the origin of short gamma-ray bursts. We use the ob…
GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs
We present the results from three gravitational-wave searches for coalescing compact binaries with component masses above 1$\mathrm{M}_\odot$ during the first and second observing runs of the Advanced gravitational-wave detector network. During the first observing run (O1), from September $12^\mathrm{th}$, 2015 to January $19^\mathrm{th}$, 2016, gravitational waves from three binary black hole mergers were detected. The second observing run (O2), which ran from November $30^\mathrm{th}$, 2016 to August $25^\mathrm{th}$, 2017, saw the first detection of gravitational waves from a binary neutron star inspiral, in addition to the observation of gravitational waves from a total of seven binary …