236 research outputs found

    BICEP2 / Keck Array VIII: Measurement of gravitational lensing from large-scale B-mode polarization

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    We present measurements of polarization lensing using the 150 GHz maps which include all data taken by the BICEP2 & Keck Array CMB polarization experiments up to and including the 2014 observing season (BK14). Despite their modest angular resolution (0.5\sim 0.5^\circ), the excellent sensitivity (3μ\sim 3\muK-arcmin) of these maps makes it possible to directly reconstruct the lensing potential using only information at larger angular scales (700\ell\leq 700). From the auto-spectrum of the reconstructed potential we measure an amplitude of the spectrum to be ALϕϕ=1.15±0.36A^{\phi\phi}_{\rm L}=1.15\pm 0.36 (Planck Λ\LambdaCDM prediction corresponds to ALϕϕ=1A^{\phi\phi}_{\rm L}=1), and reject the no-lensing hypothesis at 5.8σ\sigma, which is the highest significance achieved to date using an EB lensing estimator. Taking the cross-spectrum of the reconstructed potential with the Planck 2015 lensing map yields ALϕϕ=1.13±0.20A^{\phi\phi}_{\rm L}=1.13\pm 0.20. These direct measurements of ALϕϕA^{\phi\phi}_{\rm L} are consistent with the Λ\LambdaCDM cosmology, and with that derived from the previously reported BK14 B-mode auto-spectrum (ALBB=1.20±0.17A^{\rm BB}_{\rm L}=1.20\pm 0.17). We perform a series of null tests and consistency checks to show that these results are robust against systematics and are insensitive to analysis choices. These results unambiguously demonstrate that the B-modes previously reported by BICEP / Keck at intermediate angular scales (150350150\lesssim\ell\lesssim 350) are dominated by gravitational lensing. The good agreement between the lensing amplitudes obtained from the lensing reconstruction and B-mode spectrum starts to place constraints on any alternative cosmological sources of B-modes at these angular scales.Comment: 12 pages, 8 figure

    BICEP2 / Keck Array V: Measurements of B-mode Polarization at Degree Angular Scales and 150 GHz by the Keck Array

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    The Keck Array is a system of cosmic microwave background (CMB) polarimeters, each similar to the BICEP2 experiment. In this paper we report results from the 2012 and 2013 observing seasons, during which the Keck Array consisted of five receivers all operating in the same (150 GHz) frequency band and observing field as BICEP2. We again find an excess of B-mode power over the lensed-Λ\LambdaCDM expectation of >5σ> 5 \sigma in the range 30<<15030 < \ell < 150 and confirm that this is not due to systematics using jackknife tests and simulations based on detailed calibration measurements. In map difference and spectral difference tests these new data are shown to be consistent with BICEP2. Finally, we combine the maps from the two experiments to produce final Q and U maps which have a depth of 57 nK deg (3.4 μ\muK arcmin) over an effective area of 400 deg2^2 for an equivalent survey weight of 250,000 μ\muK2^{-2}. The final BB band powers have noise uncertainty a factor of 2.3 times better than the previous results, and a significance of detection of excess power of >6σ> 6\sigma.Comment: 13 pages, 9 figure

    Durvalumab with or without tremelimumab in patients with recurrent or metastatic head and neck squamous cell carcinoma: EAGLE, a randomized, open -label phase III study

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    Background: Targeting the programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) axis has demonstrated clinical benefit in recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC). Combining immunotherapies targeting PD-L1 and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) has shown evidence of additive activity in several tumor types. This phase III study evaluated the efficacy of durvalumab (an anti-PD-L1 monoclonal antibody) or durvalumab plus tremelimumab (an anti-CTLA-4 monoclonal antibody) versus standard of care (SoC) in R/M HNSCC patients. Patients and methods: Patients were randomly assigned to receive 1 : 1 : 1 durvalumab (10 mg/kg every 2 weeks [q2w]), durvalumab plus tremelimumab (durvalumab 20 mg/kg q4w plus tremelimumab 1 mg/kg q4w 4, then durvalumab 10 mg/kg q2w), or SoC (cetuximab, a taxane, methotrexate, or a fluoropyrimidine). The primary end points were overall survival (OS) for durvalumab versus SoC, and OS for durvalumab plus tremelimumab versus SoC. Secondary end points included progression-free survival (PFS), objective response rate, and duration of response. Results: Patients were randomly assigned to receive durvalumab (n 1⁄4 240), durvalumab plus tremelimumab (n 1⁄4 247), or SoC (n 1⁄4 249). No statistically significant improvements in OS were observed for durvalumab versus SoC [hazard ratio (HR): 0.88; 95% confidence interval (CI): 0.72e1.08; P 1⁄4 0.20] or durvalumab plus tremelimumab versus SoC (HR: 1.04; 95% CI: 0.85e1.26; P 1⁄4 0.76). The 12-month survival rates (95% CI) were 37.0% (30.9e43.1), 30.4% (24.7e36.3), and 30.5% (24.7 e36.4) for durvalumab, durvalumab plus tremelimumab, and SoC, respectively. Treatment-related adverse events (trAEs) were consistent with previous reports. The most common trAEs (any grade) were hypothyroidism for durvalumab and durvalumab plus tremelimumab (11.4% and 12.2%, respectively), and anemia (17.5%) for SoC. Grade !3 trAE rates were 10.1%, 16.3%, and 24.2% for durvalumab, durvalumab plus tremelimumab, and SoC, respectively. Conclusion: There were no statistically significant differences in OS for durvalumab or durvalumab plus tremelimumab versus SoC. However, higher survival rates at 12 to 24 months and response rates demonstrate clinical activity for durvalumab

    The Origin of the Universe as Revealed Through the Polarization of the Cosmic Microwave Background

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    Modern cosmology has sharpened questions posed for millennia about the origin of our cosmic habitat. The age-old questions have been transformed into two pressing issues primed for attack in the coming decade: How did the Universe begin? and What physical laws govern the Universe at the highest energies? The clearest window onto these questions is the pattern of polarization in the Cosmic Microwave Background (CMB), which is uniquely sensitive to primordial gravity waves. A detection of the special pattern produced by gravity waves would be not only an unprecedented discovery, but also a direct probe of physics at the earliest observable instants of our Universe. Experiments which map CMB polarization over the coming decade will lead us on our first steps towards answering these age-old questions.Comment: Science White Paper submitted to the US Astro2010 Decadal Survey. Full list of 212 author available at http://cmbpol.uchicago.ed

    Spectral Distortions of the CMB as a Probe of Inflation, Recombination, Structure Formation and Particle Physics

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    Following the pioneering observations with COBE in the early 1990s, studies of the cosmic microwave background (CMB) have focused on temperature and polarization anisotropies. CMB spectral distortions - tiny departures of the CMB energy spectrum from that of a perfect blackbody - provide a second, independent probe of fundamental physics, with a reach deep into the primordial Universe. The theoretical foundation of spectral distortions has seen major advances in recent years, which highlight the immense potential of this emerging field. Spectral distortions probe a fundamental property of the Universe - its thermal history - thereby providing additional insight into processes within the cosmological standard model (CSM) as well as new physics beyond. Spectral distortions are an important tool for understanding inflation and the nature of dark matter. They shed new light on the physics of recombination and reionization, both prominent stages in the evolution of our Universe, and furnish critical information on baryonic feedback processes, in addition to probing primordial correlation functions at scales inaccessible to other tracers. In principle the range of signals is vast: many orders of magnitude of discovery space could be explored by detailed observations of the CMB energy spectrum. Several CSM signals are predicted and provide clear experimental targets, some of which are already observable with present-day technology. Confirmation of these signals would extend the reach of the CSM by orders of magnitude in physical scale as the Universe evolves from the initial stages to its present form. The absence of these signals would pose a huge theoretical challenge, immediately pointing to new physics.Comment: Astro2020 Science White Paper, 5 pages text, 13 pages in total, 3 Figures, minor update to reference

    CMB-S4 Science Book, First Edition

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    This book lays out the scientific goals to be addressed by the next-generation ground-based cosmic microwave background experiment, CMB-S4, envisioned to consist of dedicated telescopes at the South Pole, the high Chilean Atacama plateau and possibly a northern hemisphere site, all equipped with new superconducting cameras. CMB-S4 will dramatically advance cosmological studies by crossing critical thresholds in the search for the B-mode polarization signature of primordial gravitational waves, in the determination of the number and masses of the neutrinos, in the search for evidence of new light relics, in constraining the nature of dark energy, and in testing general relativity on large scales
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