57 research outputs found

    Pre-DECIGO can get the smoking gun to decide the astrophysical or cosmological origin of GW150914-like binary black holes

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    Pre-DECIGO consists of three spacecraft arranged in an equilateral triangle with 100km arm lengths orbiting 2000km above the surface of the earth. It is hoped that the launch date will be in the late 2020s. Pre-DECIGO has one clear target: binary black holes (BBHs) like GW150914 and GW151226. Pre-DECIGO can detect 30M30M\sim 30M_\odot-30M_\odot BBH mergers up to redshift z30z\sim 30. The cumulative event rate is 1.8×105events yr1\sim 1.8\times 10^{5}\,{\rm events~yr^{-1}} in the Pop III origin model of BBHs like GW150914, and it saturates at z10z\sim 10, while in the primordial BBH (PBBH) model, the cumulative event rate is 3×104events yr1 \sim 3\times 10^{4}\,{\rm events~ yr^{-1}} at z=30z=30 even if only 0.1%0.1\% of the dark matter consists of PBHs, and it is still increasing at z=30z=30. In the Pop I/II model of BBHs, the cumulative event rate is (310)×105events yr1(3-10)\times10^{5}\,{\rm events~ yr^{-1}} and it saturates at z6z \sim 6. We present the requirements on orbit accuracy, drag free techniques, laser power, frequency stability, and interferometer test mass. For BBHs like GW150914 at 1Gpc, SNR90\sim 90 is achieved with the definition of Pre-DECIGO in the 0.011000.01-100Hz band. Pre-DECIGO can measure the mass spectrum and the zz-dependence of the merger rate to distinguish various models of BBHs like GW150914. Pre-DECIGO can also predict the direction of BBHs at z=0.1z=0.1 with an accuracy of 0.3deg2\sim 0.3\,{\rm deg}^2 and a merging time accuracy of 1\sim 1s at about a day before the merger so that ground-based GW detectors further developed at that time as well as electromagnetic follow-up observations can prepare for the detection of merger in advance. For intermediate mass BBHs at a large redshift z>10z > 10, the QNM frequency after the merger can be within the Pre-DECIGO band so that the ringing tail can also be detectable to confirm the Einstein theory of general relativity with SNR35\sim 35. [abridged]Comment: 17 pages, 10 figures, added some references, modifications to match the published version in PTE

    Effects of short-term pulmonary rehabilitation on exercise capacity and quality of life in patients with chronic obstructive pulmonary disease.

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    Although the rehabilitation of patients with chronic obstructive pulmonary disease (COPD) improves both exercise capacity and quality of life, a standard protocol for COPD patients has not been established. To clarify whether physiologic and quality-of-life improvements can be achieved by an inpatient pulmonary rehabilitation program 5 days per week for 3 weeks, 18 patients with COPD were enrolled in a rehabilitation program. The physical exercise training regimen consisted of respiratory muscle stretch gymnastics and cycle ergometer exercise training. Pulmonary function tests, an incremental ergometer exercise test, a 6-min walking test, and a quality of life assessment by the Chronic Respiratory Questionnaire were administered before and after the program. The peak VO2, an indicator of maximal exercise capacity, did not increase, although the 6-min walking distance, an indicator of functional exercise capacity, increased significantly after rehabilitation. There was a significant improvement in the quality of life in terms of dyspnea, fatigue, and emotional state. These findings suggest that even a 3-week program may be beneficial for COPD patients. Increases in functional exercise capacity, even without an increase in maximal exercise capacity, are helpful for reducing dyspnea and improving quality of life parameters in patients with COPD.</p

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Search for single production of vector-like quarks decaying into Wb in pp collisions at s=8\sqrt{s} = 8 TeV with the ATLAS detector

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    Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at s=8TeV\sqrt{s}=8\,\mathrm TeV{} with the ATLAS detector

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    Measurement of the W boson polarisation in ttˉt\bar{t} events from pp collisions at s\sqrt{s} = 8 TeV in the lepton + jets channel with ATLAS

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    Measurements of top-quark pair differential cross-sections in the eμe\mu channel in pppp collisions at s=13\sqrt{s} = 13 TeV using the ATLAS detector

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    Measurement of the bbb\overline{b} dijet cross section in pp collisions at s=7\sqrt{s} = 7 TeV with the ATLAS detector

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    ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider

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    Charged-particle distributions at low transverse momentum in s=13\sqrt{s} = 13 TeV pppp interactions measured with the ATLAS detector at the LHC

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