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IceCube Search for Neutrinos Coincident with Compact Binary Mergers from LIGO-Virgo's First Gravitational-Wave Transient Catalog
No full textUsing the IceCube Neutrino Observatory, we search for high-energy neutrino emission coincident with compact binary mergers observed by the LIGO and Virgo gravitational-wave (GW) detectors during their first and second observing runs. We present results from two searches targeting emission coincident with the sky localization of each GW event within a 1000 s time window centered around the reported merger time. One search uses a model-independent unbinned maximum-likelihood analysis, which uses neutrino data from IceCube to search for pointlike neutrino sources consistent with the sky localization of GW events. The other uses the Low-Latency Algorithm for Multi-messenger Astrophysics, which incorporates astrophysical priors through a Bayesian framework and includes LIGO-Virgo detector characteristics to determine the association between the GW source and the neutrinos. No significant neutrino coincidence is seen by either search during the first two observing runs of the LIGO-Virgo detectors. We set upper limits on the time-integrated neutrino emission within the 1000 s window for each of the 11 GW events. These limits range from 0.02 to 0.7 GeV cm . We also set limits on the total isotropic equivalent energy, E , emitted in high-energy neutrinos by each GW event. These limits range from 1.7 × 10 to 1.8 × 10 erg. We conclude with an outlook for LIGO-Virgo observing run O3, during which both analyses are running in real time
Bounds on Lorentz invariance violation from MAGIC observation of GRB 190114C
No full textOn January 14, 2019, the Major Atmospheric Gamma Imaging Cherenkov telescopes detected GRB 190114C above 0.2 TeV, recording the most energetic photons ever observed from a gamma-ray burst. We use this unique observation to probe an energy dependence of the speed of light in vacuo for photons as predicted by several quantum gravity models. Based on a set of assumptions on the possible intrinsic spectral and temporal evolution, we obtain competitive lower limits on the quadratic leading order of speed of light modification
lepton mass measurement at Belle II
No full textThe reconstruction of tau-pair production, , from the subsequent 3-prong () and 1-prong (, or ) decays, is presented using 8.8 fb of collision data of Belle II at the center-of-mass energy . The pseudomass technique developed by the ARGUS experiment is used to measure the -lepton mass in the 3-prong decay, resulting in
Search for the lepton flavor violating decay 3 in proton-proton collisions at 13 TeV
No full textResults are reported from a search for the lepton flavor violating decay 3 in proton-proton collisions at 13 TeV. The data sample corresponds to an integrated luminosity of 33.2 fb recorded by the CMS experiment at the LHC in 2016. The search exploits leptons produced in both W boson and heavy-flavor hadron decays. No significant excess above the expected background is observed. An upper limit on the branching fraction 3 of 8.0 10 at 90% confidence level is obtained, with an expected upper limit of 6.9 10
production in pp collisions with a new fragmentation function
No full textWe study inclusive -baryon production in collisions in the general-mass variable-flavor-number scheme and compare with data from the LHCb, ALICE, and CMS collaborations. We perform a new fit of the fragmentation function combining data from OPAL and Belle. The agreement with LHC data is slightly worse compared with a calculation using an older fragmentation function, and the tension between different determinations of production cross sections from the LHC experimental collaborations is not resolved. The ratio of data for -baryon and D-meson production seems to violate the universality of c-quark to c-hadron fragmentation
Search for decays to invisible final states () at Belle
No full textWe report searches for B0→invisible and B0→invisible+γ decays, where the energy of the photon is required to be larger than 0.5 GeV. These results are obtained from a 711 fb-1 data sample that contains 772×106BB¯ pairs and was collected near the ϒ(4S) resonance with the Belle detector at the KEKB e+e- collider. We observe no significant signal for either decay and set upper limits on their branching fractions at 90% confidence level of B(B0→invisible)<7.8×10-5 and B(B0→invisible+γ)<1.6×10-5
Search for resonant pair production of Higgs bosons in the bbZZ channel in proton-proton collisions at 13 TeV
No full textA search for the production of a narrow-width resonance decaying into a pair of Higgs bosons decaying into the bbZZ channel is presented. The analysis is based on data collected with the CMS detector during 2016, in proton-proton collisions at the LHC, corresponding to an integrated luminosity of 35.9 fb. The final states considered are the ones where one of the Z bosons decays into a pair of muons or electrons, and the other Z boson decays either to a pair of quarks or a pair of neutrinos. Upper limits at 95% confidence level are placed on the production of narrow-width spin-0 or spin-2 particles decaying to a pair of Higgs bosons, in models with and without an extended Higgs sector. For a resonance mass range between 260 and 1000 GeV, limits on the production cross section times branching fraction of a spin-0 and spin-2 resonance range from 0.1 to 5.0 pb and 0.1 to 3.6 pb, respectively. These results set limits in parameter space in bulk Randall-Sundrum radion, Kaluza-Klein excitation of the graviton, and N2HDM models. For specific choices of parameters the N2HDM can be excluded in a mass range between 360 and 620 GeV for a resonance decaying to two Higgs bosons. This is the first search for Higgs boson resonant pair production in the bbZZ channel
The Role of Second Phases on the Creep Behavior of As-Cast and Hot-Extruded Mg-Ca-Zr Alloys
No full textThe effect of second phases on the creep behavior of Mg-Ca-Zr alloys was investigated. Casting and hot-extrusion processes were performed to prepare Mg-xCa-0.5Zr (x = 0 wt.%, 0.3 wt.% and 0.6 wt.%) alloys with different morphologies and distributions of second phases. The as-cast microstructures of Mg-Ca-Zr alloys consisted of an Mg matrix and coarse MgCa intermetallic compounds distributed at the grain boundaries. The hot-extruded microstructures exhibited finer MgCa spherical particles and precipitates distributed homogeneously inside the matrix and along the grain boundaries. The results of creep tests suggested that the viscous glide of dislocation and dislocation climb were the dominant creep mechanisms of Mg-Ca-Zr alloys crept at 200°C. The creep property was strongly related to the morphology and distribution of the MgCa phases. The finer and more homogeneously distributed particles showed a better strengthening effect than the coarser intermetallic compounds distributed along the grain boundaries
Influence of Substrate Electronic Properties on the Integrity and Functionality of an Adsorbed Fe(II) Spin-Crossover Compound
No full textThe bistability of spin-crossover complexes on surfaces is of great interest for potential applications. Using X-ray absorption spectroscopy, we investigated the properties of [Fe(pypyr(CF))(phen)] (pypyr = 2-(2′-pyridyl)pyrrolide, phen = 1,10-phenanthroline), a vacuum-evaporable Fe(II) complex, in direct contact to a set of substrates. The electronic properties of these substrates range from metallic to semiconducting. While dissociation is observed on metal surfaces, efficient light-induced switching is realized on semimetallic and semiconducting surfaces. This indicates that the density of states of the substrate at the Fermi level plays a role for the integrity and functionality of the adsorbed compound. In an intermediate case, namely, [Fe(pypyr(CF))(phen)] on graphene/Ni(111), functional and dissociated species are found to coexist. This result indicates that some previous studies may deserve to be reconsidered because the possibility of coexisting intact and fragmented spin-crossover complexes was neglected
Insight into hydrogen effect on a duplex medium-Mn steel revealed by in-situ nanoindentation test
No full textMedium-Mn steel is the newly developed steel acting as a promising candidate of the 3rd-generation advanced high strength steels. In the present study, the effect of hydrogen on the mechanical behavior and martensite transformation process in a duplex medium-Mn steel is investigated by in-situ nanoindentation test. The mechanical response of individual phase: ferrite, and retained austenite by introducing hydrogen is studied. With the presence of hydrogen, the reduction of activation energy for dislocation nucleation was verified by using a stress-biased, statistical thermal activation model. The stacking fault energy (SFE) was reduced, which was revealed by electron channeling contrast (ECC) technique. Magnetic force microscopy (MFM) revealed a suppression of retained austenite to α′-martensite transformation with the presence of hydrogen, which is related to hydrogen induced SFE reduction and enhanced slip planarity