93 research outputs found

    Detector Description and Performance for the First Coincidence Observations between LIGO and GEO

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    For 17 days in August and September 2002, the LIGO and GEO interferometer gravitational wave detectors were operated in coincidence to produce their first data for scientific analysis. Although the detectors were still far from their design sensitivity levels, the data can be used to place better upper limits on the flux of gravitational waves incident on the earth than previous direct measurements. This paper describes the instruments and the data in some detail, as a companion to analysis papers based on the first data.Comment: 41 pages, 9 figures 17 Sept 03: author list amended, minor editorial change

    Search for Gravitational Waves from Primordial Black Hole Binary Coalescences in the Galactic Halo

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    We use data from the second science run of the LIGO gravitational-wave detectors to search for the gravitational waves from primordial black hole (PBH) binary coalescence with component masses in the range 0.2--1.0M1.0 M_\odot. The analysis requires a signal to be found in the data from both LIGO observatories, according to a set of coincidence criteria. No inspiral signals were found. Assuming a spherical halo with core radius 5 kpc extending to 50 kpc containing non-spinning black holes with masses in the range 0.2--1.0M1.0 M_\odot, we place an observational upper limit on the rate of PBH coalescence of 63 per year per Milky Way halo (MWH) with 90% confidence.Comment: 7 pages, 4 figures, to be submitted to Phys. Rev.

    Updated Nucleosynthesis Constraints on Unstable Relic Particles

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    We revisit the upper limits on the abundance of unstable massive relic particles provided by the success of Big-Bang Nucleosynthesis calculations. We use the cosmic microwave background data to constrain the baryon-to-photon ratio, and incorporate an extensively updated compilation of cross sections into a new calculation of the network of reactions induced by electromagnetic showers that create and destroy the light elements deuterium, he3, he4, li6 and li7. We derive analytic approximations that complement and check the full numerical calculations. Considerations of the abundances of he4 and li6 exclude exceptional regions of parameter space that would otherwise have been permitted by deuterium alone. We illustrate our results by applying them to massive gravitinos. If they weigh ~100 GeV, their primordial abundance should have been below about 10^{-13} of the total entropy. This would imply an upper limit on the reheating temperature of a few times 10^7 GeV, which could be a potential difficulty for some models of inflation. We discuss possible ways of evading this problem.Comment: 40 pages LaTeX, 18 eps figure

    TOI-269 b: An eccentric sub-Neptune transiting a M2 dwarf revisited with ExTrA

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    We present the confirmation of a new sub-Neptune close to the transition between super-Earths and sub-Neptunes transiting the M2 dwarf TOI-269 (TIC 220 479 565, V = 14.4 mag, J = 10.9 mag, Ro = 0.40 Ro, Mo = 0.39 Mo, d = 57 pc). The exoplanet candidate has been identified in multiple TESS sectors, and validated with high-precision spectroscopy from HARPS and ground-based photometric follow-up from ExTrA and LCO-CTIO. We determined mass, radius, and bulk density of the exoplanet by jointly modeling both photometry and radial velocities with juliet. The transiting exoplanet has an orbital period of P = 3.6977104 ± 0.0000037 days, a radius of 2.77 ± 0.12 R·, and a mass of 8.8 ± 1.4 M·. Since TOI-269 b lies among the best targets of its category for atmospheric characterization, it would be interesting to probe the atmosphere of this exoplanet with transmission spectroscopy in order to compare it to other sub-Neptunes. With an eccentricity e = 0.425-0.086+0.082, TOI-269 b has one of the highest eccentricities of the exoplanets with periods less than 10 days. The star being likely a few Gyr old, this system does not appear to be dynamically young. We surmise TOI-269 b may have acquired its high eccentricity as it migrated inward through planet-planet interactions

    A comparative study on the modeling of dynamic after-cavity interaction in gyrotrons

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    There are cases where gyrotron interaction simulations predict dynamic After-Cavity Interaction (ACI). In dynamic ACI, a mode is excited by the electron beam at a dominant frequency in the gyrotron cavity and, at the same time, this mode is also interacting with the beam at a different frequency in the non-linear uptaper after the cavity. In favor of dynamic ACI being a real physical effect, there are some experimental findings that could be attributed to it, as well as some physical rationale indicating the possibility of a mode being resonant with the beam at different frequencies in different regions. However, the interaction codes used in dynamic ACI prediction up to now are based on simplifications that put questions on their capability of correctly simulating this effect. In this work, the shortcomings of the usual simplifications with respect to dynamic ACI modeling, namely, the trajectory approach and the single-frequency boundary condition, are identified. Extensive simulations of dynamic ACI cases are presented, using several "in-house" as well as commercial codes. We report on the comparison and the assessment of different modeling approaches and their results and we discuss whether, in some cases, dynamic ACI can be a numerical artifact or not. Although the possibility of existence of dynamic ACI in gyrotrons is not disputed, it is concluded that the widely used trajectory approach for gyrotron interaction modeling is questionable for simulating dynamic ACI and can lead to misleading results. © 2015 EURATOM

    Randomized phase II study of sunitinib versus standard of care forpatients with previously treated advanced triple-negative breast cancer

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    Purpose: This randomized, open-label phase II study compared the efficacy of sunitinib monotherapy with that of single-agent standard-of-care (SOC) chemotherapy in patients with previously treated advanced triple-negative breast cancer (TNBC). Methods: Patients with advanced TNBC, relapsed after anthracycline- and taxane-based chemotherapy, were randomized to receive either sunitinib (37.5mg/day) or the investigator's choice of SOC therapy. Progression-free survival was the primary endpoint. Results: Median progression-free survival was 2.0 months with sunitinib and 2.7 months with SOC chemotherapy (one-sided P=0.888). Median overall survival was not prolonged with sunitinib (9.4 months) compared with SOC chemotherapy (10.5 months; one-sided P=0.839). The objective response rate was 3% with sunitinib and 7% with SOC chemotherapy (one-sided P=0.962). Conclusions: Sunitinib monotherapy did not improve efficacy compared with SOC chemotherapy in patients with previously treated advanced TNBC, for which identification of effective treatments and therapeutic targets remains an urgent need. Trial registration: NCT00246571
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