150 research outputs found
Construction of Field Algebras with Quantum Symmetry from Local Observables
It has been discussed earlier that ( weak quasi-) quantum groups allow for
conventional interpretation as internal symmetries in local quantum theory.
From general arguments and explicit examples their consistency with (braid-)
statistics and locality was established. This work addresses to the
reconstruction of quantum symmetries and algebras of field operators. For every
algebra \A of observables satisfying certain standard assumptions, an
appropriate quantum symmetry is found. Field operators are obtained which act
on a positive definite Hilbert space of states and transform covariantly under
the quantum symmetry. As a substitute for Bose/Fermi (anti-) commutation
relations, these fields are demonstrated to obey local braid relation.Comment: 50 pages, HUTMP 93-B33
Nuclear transparency from quasielastic A(e,e'p) reactions uo to Q^2=8.1 (GeV/c)^2
The quasielastic (e,ep) reaction was studied on targets of
deuterium, carbon, and iron up to a value of momentum transfer of 8.1
(GeV/c). A nuclear transparency was determined by comparing the data to
calculations in the Plane-Wave Impulse Approximation. The dependence of the
nuclear transparency on and the mass number was investigated in a
search for the onset of the Color Transparency phenomenon. We find no evidence
for the onset of Color Transparency within our range of . A fit to the
world's nuclear transparency data reflects the energy dependence of the free
proton-nucleon cross section.Comment: 11 pages, 6 figure
Cognitive Interview-Based Validation of the Patient-Reported Outcomes Version of the Common Terminology Criteria for Adverse Events in Adolescents with Cancer
Context The National Cancer Institute created the Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) to allow direct input on symptomatic adverse events (AEs) from adult patients in oncology trials. Objectives This study sought to determine the youngest age to complete the PRO-CTCAE, evaluated comprehension of PRO-CTCAE among adolescents, tested new items not currently in PRO-CTCAE, and tested a parent-proxy version. Methods From seven pediatric cancer hospitals, 51 adolescents (13–20 years) receiving cancer treatment participated, along with 40 parent proxies. We evaluated 55 AEs from the PRO-CTCAE library (97 questions) and seven new AEs not in PRO-CTCAE that assess symptom frequency, severity, interference, or presence. Questions were distributed across three forms to reduce burden. Cognitive interviews with retrospective probing were completed in age groups of 13–15 and 16–20 year olds. Proxies were interviewed independently. Results In general, the 16–20 year olds and the parent proxies were able to understand and complete the PRO-CTCAE and newly designed AE questions. Five PRO-CTCAE terms (bloating of the abdomen, anxiety, flashing lights in front of your eyes, hot flashes, and bed sores) and the wording of the questions about AE severity were challenging for a few adolescents and proxies. The 13–15 year olds had greater challenges completing the PRO-CTCAE. Conclusion This study extends use of the adult PRO-CTCAE for adolescents as young as 16 years and proposes new questions for seven new symptomatic AEs and a parent-proxy version of PRO-CTCAE. Additional testing of the new questions and alternative language for more challenging PRO-CTCAE items is recommended in adults
The G0 Experiment: Apparatus for Parity-Violating Electron Scattering Measurements at Forward and Backward Angles
In the G0 experiment, performed at Jefferson Lab, the parity-violating
elastic scattering of electrons from protons and quasi-elastic scattering from
deuterons is measured in order to determine the neutral weak currents of the
nucleon. Asymmetries as small as 1 part per million in the scattering of a
polarized electron beam are determined using a dedicated apparatus. It consists
of specialized beam-monitoring and control systems, a cryogenic hydrogen (or
deuterium) target, and a superconducting, toroidal magnetic spectrometer
equipped with plastic scintillation and aerogel Cerenkov detectors, as well as
fast readout electronics for the measurement of individual events. The overall
design and performance of this experimental system is discussed.Comment: Submitted to Nuclear Instruments and Method
Gravitational Radiation From Cosmological Turbulence
An injection of energy into the early Universe on a given characteristic
length scale will result in turbulent motions of the primordial plasma. We
calculate the stochastic background of gravitational radiation arising from a
period of cosmological turbulence, using a simple model of isotropic
Kolmogoroff turbulence produced in a cosmological phase transition. We also
derive the gravitational radiation generated by magnetic fields arising from a
dynamo operating during the period of turbulence. The resulting gravitational
radiation background has a maximum amplitude comparable to the radiation
background from the collision of bubbles in a first-order phase transition, but
at a lower frequency, while the radiation from the induced magnetic fields is
always subdominant to that from the turbulence itself. We briefly discuss the
detectability of such a signal.Comment: 20 pages. Corrections for an errant factor of 2 in all the gravity
wave characteristic amplitudes. Accepted for publication in Phys. Rev.
The state of the Martian climate
60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
KELT-6b: A P ~ 7.9 Day Hot Saturn Transiting A Metal-Poor Star With A Long-Period Companion
We report the discovery of KELT-6b, a mildly inflated Saturn-mass planet transiting a metal-poor host. The initial transit signal was identified in KELT-North survey data, and the planetary nature of the occulter was established using a combination of follow-up photometry, high-resolution imaging, high-resolution spectroscopy, and precise radial velocity measurements. The fiducial model from a global analysis including constraints from isochrones indicates that the V = 10.38 host star (BD+31 2447) is a mildly evolved, late-F star with T eff = 6102 ± 43 K, log g_\star =4.07_{-0.07}^{+0.04}, and [Fe/H] = -0.28 ± 0.04, with an inferred mass M sstarf = 1.09 ± 0.04 M ☉ and radius R_\star =1.58_{-0.09}^{+0.16} \,R_\odot. The planetary companion has mass MP = 0.43 ± 0.05 M Jup, radius R_{P}=1.19_{-0.08}^{+0.13} \,R_Jup, surface gravity log g_{P}=2.86_{-0.08}^{+0.06}, and density \rho _{P}=0.31_{-0.08}^{+0.07}\,g\,cm^{-3}. The planet is on an orbit with semimajor axis a = 0.079 ± 0.001 AU and eccentricity e=0.22_{-0.10}^{+0.12}, which is roughly consistent with circular, and has ephemeris of T c(BJDTDB) = 2456347.79679 ± 0.00036 and P = 7.845631 ± 0.000046 days. Equally plausible fits that employ empirical constraints on the host-star parameters rather than isochrones yield a larger planet mass and radius by ~4}-7}. KELT-6b has surface gravity and incident flux similar to HD 209458b, but orbits a host that is more metal poor than HD 209458 by ~0.3 dex. Thus, the KELT-6 system offers an opportunity to perform a comparative measurement of two similar planets in similar environments around stars of very different metallicities. The precise radial velocity data also reveal an acceleration indicative of a longer-period third body in the system, although the companion is not detected in Keck adaptive optics images.KELT is a joint project of The Ohio State University, Vanderbilt University, and Lehigh University
KELT-6b: A P ~ 7.9 Day Hot Saturn Transiting a Metal-poor Star with a Long-period Companion
We report the discovery of KELT-6b, a mildly inflated Saturn-mass planet transiting a metal-poor host. The initial transit signal was identified in KELT-North survey data, and the planetary nature of the occulter was established using a combination of follow-up photometry, high-resolution imaging, high-resolution spectroscopy, and precise radial velocity measurements. The fiducial model from a global analysis including constraints from isochrones indicates that the V = 10.38 host star (BD+31 2447) is a mildly evolved, late-F star with T eff = 6102 ± 43 K, , and [Fe/H] = –0.28 ± 0.04, with an inferred mass M = 1.09 ± 0.04 M ☉ and radius . The planetary companion has mass MP = 0.43 ± 0.05 M Jup, radius , surface gravity , and density . The planet is on an orbit with semimajor axis a = 0.079 ± 0.001 AU and eccentricity , which is roughly consistent with circular, and has ephemeris of T c(BJDTDB) = 2456347.79679 ± 0.00036 and P = 7.845631 ± 0.000046 days. Equally plausible fits that employ empirical constraints on the host-star parameters rather than isochrones yield a larger planet mass and radius by ~4}-7}. KELT-6b has surface gravity and incident flux similar to HD 209458b, but orbits a host that is more metal poor than HD 209458 by ~0.3 dex. Thus, the KELT-6 system offers an opportunity to perform a comparative measurement of two similar planets in similar environments around stars of very different metallicities. The precise radial velocity data also reveal an acceleration indicative of a longer-period third body in the system, although the companion is not detected in Keck adaptive optics images
Coherent π0 photoproduction on the deuteron up to 4 GeV
The differential cross section for 2H(γ,d)π0 has been measured at deuteron center-of-mass angles of 90° and 136°. This work reports the first data for this reaction above a photon energy of 1 GeV, and permits a test of the apparent constituent counting rule and reduced nuclear amplitude behavior as observed in elastic ed scattering. Measurements were performed up to a photon energy of 4.0 GeV, and are in good agreement with previous lower energy measurements. Overall, the data are inconsistent with both constituent-counting rule and reduced nuclear amplitude predictions
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