471 research outputs found

    Josephson current in s-wave superconductor / Sr_2RuO_4 junctions

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    The Josephson current between an s-wave and a spin-triplet superconductor Sr2_2RuO4_4 (SRO) is studied theoretically. In spin-singlet / spin-triplet superconductor junctions, there is no Josephson current proportional to sinϕ\sin \phi in the absence of the spin-flip scattering near junction interfaces, where ϕ\phi is a phase-difference across junctions. Thus a dominant term of the Josephson current is proportional to sin2ϕ\sin 2\phi . The spin-orbit scattering at the interfaces gives rise to the Josephson current proportional to cosϕ\cos\phi, which is a direct consequence of the chiral paring symmetry in SRO

    The Prevalence of Knee Symptoms, Radiographic, and Symptomatic Osteoarthritis at Four Time Points: The Johnston County Osteoarthritis Project, 1999-2018

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    Objective: To describe point prevalence of knee symptoms, radiographic knee osteoarthritis (rKOA), severe rKOA, and symptomatic rKOA at four time points in the longitudinal, population-based Johnston County Osteoarthritis Project (JoCo OA). Methods: Data were from 2573 JoCo OA participants with up to 18 years of follow-up (1999-2018) and standardized fixed-flexion knee radiographs read by a single, reliable expert musculoskeletal radiologist. The four outcomes were 1) self-reported knee symptoms, defined by “On most days, do you have pain, aching, or stiffness in your right/left knee?”; 2) rKOA, defined as a Kellgren-Lawrence grade (KLG) of 2 to 4); 3) severe rKOA, defined as a KLG of 3 or 4; and 4) symptomatic rKOA, defined as both symptoms and rKOA in the same joint. Weighted prevalence estimates and 95% confidence intervals (CIs) were generated overall and by age group, sex, race, and body mass index (BMI). Results: Most recently (2017-2018, T4), the overall prevalence (percentage) of knee symptoms, rKOA, severe rKOA, and symptomatic rKOA was 41% (95% CI: 35-47%), 61% (95% CI: 56-67%), 35% (95% CI: 30-40%), and 30% (95% CI: 24-35%), respectively. From time point T1 to T4, prevalence increased for rKOA, severe rKOA, and symptomatic rKOA but not for knee symptoms. The prevalence of both severe rKOA (17-39%) and symptomatic rKOA (23-30%) was consistently higher among women. The prevalence of all outcomes was higher among those with higher BMI and among Black participants at all time points, particularly rKOA (35-69%) and severe rKOA (22-46%). Conclusion: These updated estimates demonstrate a large and increasing burden of knee OA, particularly among women and Black individuals

    Spiral Galaxies as Chiral Objects?

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    Spiral galaxies show axial symmetry and an intrinsic 2D-chirality. Environmental effects can influence the chirality of originally isolated stellar systems and a progressive loss of chirality can be recognised in the Hubble sequence. We point out a preferential modality for genetic galaxies as in microscopic systems like aminoacids, sugars or neutrinos. This feature could be the remnant of a primordial symmetry breaking characterizing systems at all scales.Comment: 10 pages, 3 figure

    Cosmological distance indicators

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    We review three distance measurement techniques beyond the local universe: (1) gravitational lens time delays, (2) baryon acoustic oscillation (BAO), and (3) HI intensity mapping. We describe the principles and theory behind each method, the ingredients needed for measuring such distances, the current observational results, and future prospects. Time delays from strongly lensed quasars currently provide constraints on H0H_0 with < 4% uncertainty, and with 1% within reach from ongoing surveys and efforts. Recent exciting discoveries of strongly lensed supernovae hold great promise for time-delay cosmography. BAO features have been detected in redshift surveys up to z <~ 0.8 with galaxies and z ~ 2 with Ly-α\alpha forest, providing precise distance measurements and H0H_0 with < 2% uncertainty in flat Λ\LambdaCDM. Future BAO surveys will probe the distance scale with percent-level precision. HI intensity mapping has great potential to map BAO distances at z ~ 0.8 and beyond with precisions of a few percent. The next years ahead will be exciting as various cosmological probes reach 1% uncertainty in determining H0H_0, to assess the current tension in H0H_0 measurements that could indicate new physics.Comment: Review article accepted for publication in Space Science Reviews (Springer), 45 pages, 10 figures. Chapter of a special collection resulting from the May 2016 ISSI-BJ workshop on Astronomical Distance Determination in the Space Ag

    Observation of exclusive DVCS in polarized electron beam asymmetry measurements

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    We report the first results of the beam spin asymmetry measured in the reaction e + p -> e + p + gamma at a beam energy of 4.25 GeV. A large asymmetry with a sin(phi) modulation is observed, as predicted for the interference term of Deeply Virtual Compton Scattering and the Bethe-Heitler process. The amplitude of this modulation is alpha = 0.202 +/- 0.028. In leading-order and leading-twist pQCD, the alpha is directly proportional to the imaginary part of the DVCS amplitude.Comment: 6 pages, 5 figure

    Complete measurement of three-body photodisintegration of 3He for photon energies between 0.35 and 1.55 GeV

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    The three-body photodisintegration of 3He has been measured with the CLAS detector at Jefferson Lab, using tagged photons of energies between 0.35 GeV and 1.55 GeV. The large acceptance of the spectrometer allowed us for the first time to cover a wide momentum and angular range for the two outgoing protons. Three kinematic regions dominated by either two- or three-body contributions have been distinguished and analyzed. The measured cross sections have been compared with results of a theoretical model, which, in certain kinematic ranges, have been found to be in reasonable agreement with the data.Comment: 22 pages, 25 eps figures, 2 tables, submitted to PRC. Modifications: removed 2 figures, improvements on others, a few minor modifications to the tex

    A Kinematically Complete Measurement of the Proton Structure Function F2 in the Resonance Region and Evaluation of Its Moments

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    We measured the inclusive electron-proton cross section in the nucleon resonance region (W < 2.5 GeV) at momentum transfers Q**2 below 4.5 (GeV/c)**2 with the CLAS detector. The large acceptance of CLAS allowed for the first time the measurement of the cross section in a large, contiguous two-dimensional range of Q**2 and x, making it possible to perform an integration of the data at fixed Q**2 over the whole significant x-interval. From these data we extracted the structure function F2 and, by including other world data, we studied the Q**2 evolution of its moments, Mn(Q**2), in order to estimate higher twist contributions. The small statistical and systematic uncertainties of the CLAS data allow a precise extraction of the higher twists and demand significant improvements in theoretical predictions for a meaningful comparison with new experimental results.Comment: revtex4 18 pp., 12 figure

    eta-prime photoproduction on the proton for photon energies from 1.527 to 2.227 GeV

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    Differential cross sections for the reaction gamma p -> eta-prime p have been measured with the CLAS spectrometer and a tagged photon beam with energies from 1.527 to 2.227 GeV. The results reported here possess much greater accuracy than previous measurements. Analyses of these data indicate for the first time the coupling of the etaprime N channel to both the S_11(1535) and P_11(1710) resonances, known to couple strongly to the eta N channel in photoproduction on the proton, and the importance of j=3/2 resonances in the process.Comment: 6 pages, 3 figure

    Measurement of the Deuteron Structure Function F2 in the Resonance Region and Evaluation of Its Moments

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    Inclusive electron scattering off the deuteron has been measured to extract the deuteron structure function F2 with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. The measurement covers the entire resonance region from the quasi-elastic peak up to the invariant mass of the final-state hadronic system W~2.7 GeV with four-momentum transfers Q2 from 0.4 to 6 (GeV/c)^2. These data are complementary to previous measurements of the proton structure function F2 and cover a similar two-dimensional region of Q2 and Bjorken variable x. Determination of the deuteron F2 over a large x interval including the quasi-elastic peak as a function of Q2, together with the other world data, permit a direct evaluation of the structure function moments for the first time. By fitting the Q2 evolution of these moments with an OPE-based twist expansion we have obtained a separation of the leading twist and higher twist terms. The observed Q2 behaviour of the higher twist contribution suggests a partial cancellation of different higher twists entering into the expansion with opposite signs. This cancellation, found also in the proton moments, is a manifestation of the "duality" phenomenon in the F2 structure function
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