Using the CLEO II detector, we have measured the differential cross sections for exclusive two-photon production of light pseudoscalar mesons 0 , , and Ј. From our measurements we have obtained the form factors associated with the electromagnetic transitions ␥*␥→meson. We have measured these form factors in the momentum transfer ranges from 1.5 to 9, 20, and 30 GeV 2 for 0 , , and Ј, respectively, and have made comparisons to various theoretical predictions. ͓S0556-2821͑98͒01001-7͔
This document on the CMB-S4 Science Case, Reference Design, and Project Plan is the product of a global community of scientists who are united in support of advancing CMB-S4 to cross key thresholds in our understanding of the fundamental nature of space and time and the evolution of the Universe. CMB-S4 is planned to be a joint National Science Foundation (NSF) and Department of Energy (DOE) project, with the construction phase to be funded as an NSF Major Research Equipment and Facilities Construction (MREFC) project and a DOE High Energy Physics (HEP) Major Item of Equipment (MIE) project. At the time of this writing, an interim project office has been constituted and tasked with advancing the CMB-S4 project in the NSF MREFC Preliminary Design Phase and toward DOE Critical Decision CD-1. DOE CD-0 is expected imminently.CMB-S4 has been in development for six years. Through the Snowmass Cosmic Frontier planning process, experimental groups in the cosmic microwave background (CMB) and broader cosmology communities came together to produce two influential CMB planning papers, endorsed by over 90 scientists, that outlined the science case as well as the CMB-S4 instrumental concept [1, 2]. It immediately became clear that an enormous increase in the scale of ground-based CMB experiments would be needed to achieve the exciting thresholdcrossing scientific goals, necessitating a phase change in the ground-based CMB experimental program. To realize CMB-S4, a partnership of the university-based CMB groups, the broader cosmology community, and the national laboratories would be needed.The community proposed CMB-S4 to the 2014 Particle Physics Project Prioritization Process (P5) as a single, community-wide experiment, jointly supported by DOE and NSF. Following P5's recommendation of CMB-S4 under all budget scenarios, the CMB community started in early 2015 to hold biannual workshops -open to CMB scientists from around the world -to develop and refine the concept. Nine workshops have been held to date, typically with 150 to 200 participants. The workshops have focused on developing the unique and vital role of the future ground-based CMB program. This growing CMB-S4 community produced a detailed and influential CMB-S4 Science Book [3] and a CMB-S4 Technology Book [4]. Over 200 scientists contributed to these documents. These and numerous other reports, workshop and working group wiki pages, email lists, and much more may be found at the website http://CMB-S4.org.Soon after the CMB-S4 Science Book was completed in August 2016, DOE and NSF requested the Astronomy and Astrophysics Advisory Committee (AAAC) to convene a Concept Definition Taskforce (CDT) to conduct a CMB-S4 concept study. The resulting report was unanimously accepted in late 2017. 1 One recommendation of the CDT report was that the community should organize itself into a formal collaboration. An Interim Collaboration Coordination Committee was elected by the community to coordinate this process. The resulting draft bylaws were refined at the Spring 2018 CMB-S4...
We report measurements of the electroproduction of single charged pions from hydrogen and deuterium targets for values of r in the range 0.35 < r < 0.45. Data were taken with a hydrogen target at the (W,Q ' ) points (2.15 GeV, 1.2 G~v~) ,(2.65, 2.0), (2.65, 3.4), (2.65, 6.0), and (2.65, 10.0). Data were taken with a deuterium target at the (W, Q ' ) points (2.15, 1.2) and (2.65, 2.0). The transverse cross section obtained by using these data in conjunction with earlier data at high E to separate the longitudinal and transverse components is used in ~onj~unction with the new data and the t -channel Born term to determine the pion form factor and to re-evaluate previously reported measurements. In the range 0.15 G~V~ < Q < 10.0 GeVZ the ' pion form factor can be described by the simple pole form [I + Q 2/(0.462 + 0.024)]-'.
We have observed the decays B° -» K*(892)°j and B~ -> K*(892)~ry, which are evidence for the quark-level process b -• 57. The average branching fraction is (4.5 ± 1.5 ± 0.9) x 10~5. This value is consistent with standard model predictions from electromagnetic penguin diagrams. PACS numbers: 13.40.Hq, 14.40.Jz One-loop, flavor-changing neutral current diagrams, meson decays [1]. They were later identified as a possible known as penguins, were originally introduced into the source of direct CP violation in kaon decay, and hence as theory of weak decays to explain the AI = \ rule in K a contribution to e! /e [2]. Their importance in B meson 674 0031 -9007/93/71 (5)/674(5)$06.00
CMB-S4—the next-generation ground-based cosmic microwave background (CMB) experiment—is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the universe. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semianalytic projection tool, targeted explicitly toward optimizing constraints on the tensor-to-scalar ratio, r, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2–3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments, given a desired scientific goal. To form a closed-loop process, we couple this semianalytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for r > 0.003 at greater than 5σ, or in the absence of a detection, of reaching an upper limit of r < 0.001 at 95% CL.
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