Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

DISRUPTING THE ISI-TALIBAN RELATIONSHIP: A PRINCIPAL-AGENT APPROACH

This study argues that principal-agent theory provides a unique perspective on the relationship between the Afghan Taliban and the Pakistani state. This perspective assists in developing strategies to reduce, disrupt, or eliminate the support that the Taliban receive from Pakistan. Furthermore, the framework of this study can be applied to other state-sponsored terrorist groups, insurgencies, and proxies.http://archive.org/details/disruptingtheisi1094561387Major, United States ArmyMajor, United States ArmyApproved for public release; distribution is unlimited

Framing the Post-2020 Afghan Environment: Thoughts and Recommendations

This research aims to augment the reader’s strategic appreciation for the post-2020 environment in Afghanistan. As such, the authors consider this a “thought piece” versus a policy prescriptive decision briefing or white paper. The near-term goal is to inform the NATO Special Operations Component Command – Afghanistan/Special Operations Joint Task Force – Afghanistan (NSOCC-A/SOJTF-A) Commander and his staff on crucial variables that may prove consequential in the forthcoming development of a campaign design for the future utilization of Special Operations Forces (SOF) in Afghanistan, while also providing a collection of ‘creative options’ that could be injected into future SOF campaign plans in order to influence the aforementioned variables. For this analysis, the authors consciously present a holistic look at Afghanistan, accounting for variables and circumstances beyond SOJTF-A’s authorities or sphere of influence. The expanded scope was purposefully chosen to present a comprehensive understanding of the environment in which SOJTF-A leadership employs the SOF enterprise.Commander, NSOCC-A/SOJTF-ACommander, NSOCC-A/SOJTF-