70,103 research outputs found

    Consistent analysis of neutral- and charged-current neutrino scattering off carbon

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    Background: Good understanding of the cross sections for (anti)neutrino scattering off nuclear targets in the few-GeV energy region is a prerequisite for correct interpretation of results of ongoing and planned oscillation experiments. Purpose: Clarify possible source of disagreement between recent measurements of the cross sections on carbon. Method: Nuclear effects in (anti)neutrino scattering off carbon nucleus are described using the spectral function approach. The effect of two- and multi-nucleon final states is accounted for by applying an effective value of the axial mass, fixed to 1.23 GeV. Neutral-current elastic (NCE) and charged-current quasielastic (CCQE) processes are treated on equal footing. Results: The differential and total cross sections for the energy ranging from a few hundreds of MeV to 100 GeV are obtained and compared to the available data from the BNL E734, MiniBooNE, and NOMAD experiments. Conclusions: Nuclear effects in NCE and CCQE scattering seem to be very similar. Within the spectral function approach, the axial mass from the shape analysis of the MiniBooNE data is in good agreement with the results reported by the BNL E734 and NOMAD Collaborations. However, the combined analysis of NCE and CCQE data does not seem to support the contribution of multi-nucleon final states being large enough to explain the normalization of the MiniBooNE-reported cross sections.Comment: 14 pages, 9 figures, detailed discussion of the role of FSI is adde

    B Physics with NRQCD: A Quenched Study

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    We present results on the spectrum of B mesons and heavy baryons, using a non-relativistic formulation for the heavy and a clover action for the light quark. We also discuss B meson decay constants and their dependency upon the heavy meson mass.Comment: 4 pages, uuencoded compressed postscript file, contribution to LATTICE 9

    Guidelines for the management of the foot health problems associated with rheumatoid arthritis

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    Background. Rheumatoid arthritis (RA) as a chronic systemic disease, commonly affects the feet, impacting negatively on patients' quality of life. Specialist podiatrists have a prime role to play in the assessment and management of foot and ankle problems within this patient group. However, it has been identified that in many areas there is no specialist podiatry service, with many patients being managed by non‐specialist podiatrists. Therefore, the North West Clinical Effectiveness Group for the Foot in Rheumatic Diseases (NWCEG) identified the need to develop ‘practitioner facing’ guidelines for the management of specific foot health problems associated with RA. Methods. Members of a guideline development group from the NWCEG each reviewed the evidence for specific aspects of the assessment and management of foot problems. Where evidence was lacking, ‘expert opinion’ was obtained from the members of the NWCEG and added as a consensus on current and best practice. An iterative approach was employed, with the results being reviewed and revised by all members of the group and external reviewers before the final guideline document was produced. Results. The management of specific foot problems (callus, nail pathology, ulceration) and the use of specific interventions (foot orthoses, footwear, patient education, steroid injection therapy) are detailed and standards in relation to each are provided. A diagrammatic screening pathway is presented, with the aim of guiding nonspecialist podiatrists through the complexity of assessing and managing those patients with problems requiring input from a specialist podiatrist and other members of the rheumatology multidisciplinary team. Conclusion. This pragmatic approach ensured that the guidelines were relevant and applicable to current practice as ‘best practice’, based on the available evidence from the literature and consensus expert opinion. These guidelines provide both specialist and non‐specialist podiatrists with the essential and ‘gold standard’ aspects of managing people with RA‐related foot problems

    Quantum black holes in Type-IIA String Theory

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    We study black hole solutions of Type-IIA Calabi-Yau compactifications in the presence of perturbative quantum corrections. We define a class of black holes that only exist in the presence of quantum corrections and that, consequently, can be considered as purely quantum black holes. The regularity conditions of the solutions impose the topological constraint h^{1,1}>h^{2,1} on the Calabi-Yau manifold, defining a class of admissible compactifications, which we prove to be non-empty for h^{1,1}=3 by explicitly constructing the corresponding Calabi-Yau manifolds, new in the literature.Comment: 17 pages. References added. Explanation of the truncation improve

    New Cosmological Structures on Medium Angular Scales Detected with the Tenerife Experiments

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    We present observations at 10 and 15 GHz taken with the Tenerife experiments in a band of the sky at Dec.=+35 degrees. These experiments are sensitive to multipoles in the range l=10-30. The sensitivity per beam is 56 and 20 microK for the 10 and the 15 GHz data, respectively. After subtraction of the prediction of known radio-sources, the analysis of the data at 15 GHz at high Galactic latitude shows the presence of a signal with amplitude Delta Trms ~ 32 microK. In the case of a Harrison-Zeldovich spectrum for the primordial fluctuations, a likelihood analysis shows that this signal corresponds to a quadrupole amplitude Q_rms-ps=20.1+7.1-5.4 microK, in agreement with our previous results at Dec.+=40 degrees and with the results of the COBE DMR. There is clear evidence for the presence of individual features in the RA range 190 degrees to 250 degrees with a peak to peak amplitude of ~110 microK. A preliminary comparison between our results and COBE DMR predictions for the Tenerife experiments clearly indicates the presence of individual features common to both. The constancy in amplitude over such a large range in frequency (10-90 GHz) is strongly indicative of an intrinsic cosmological origin for these structures.Comment: ApJ Letters accepted, 13 pages Latex (uses AASTEX) and 4 encapsulated postscript figures

    Scaling and Further Tests of Heavy Meson Decay Constant Determinations from Nonrelativistic QCD

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    We present results for the B_s meson decay constant f_{B_s} from simulations at three lattice spacings in the range a^{-1}=1.1 to 2.6 GeV using NRQCD heavy quarks and clover light quarks in the quenched approximation. We study scaling of this quantity and check the consistency between mesons decaying from rest and from a state with nonzero spatial momentum. The cancellation of power law contributions that arise in the NRQCD formulation of heavy-light currents is discussed. On the coarsest lattice the D_s meson decay constant f_{D_s} is calculated. Our best values for the decay constants are given by f_{B_s} = 187(4)(4)(11)(2)(7)(6) MeV and f_{D_s} = 223(6)(31)(38)(23)(9)(^{+3}_{-1}) MeV.Comment: 29 pages with 7 postscript figures, improved error analysis, version to appear in Physical Review

    CBI limits on 31 GHz excess emission in southern HII regions

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    We have mapped four regions of the southern Galactic plane at 31 GHz with the Cosmic Background Imager. From the maps, we have extracted the flux densities for six of the brightest \hii regions in the southern sky and compared them with multi-frequency data from the literature. The fitted spectral index for each source was found to be close to the theoretical value expected for optically thin free-free emission, thus confirming that the majority of flux at 31 GHz is due to free-free emission from ionised gas with an electron temperature of 70008000\approx 7000-8000 K. We also found that, for all six sources, the 31 GHz flux density was slightly higher than the predicted value from data in the literature. This excess emission could be due to spinning dust or another emission mechanism. Comparisons with 100μ100 \mum data indicate an average dust emissivity of 3.3±1.7μ3.3\pm1.7 \muK (MJy/sr)1^{-1}, or a 95 per cent confidence limit of <6.1μ<6.1 \muK (MJy/sr)1^{-1}. This is lower than that found in diffuse clouds at high Galactic latitudes by a factor of 34\sim 3-4. The most significant detection (3.3σ3.3\sigma) was found in G284.30.3G284.3-0.3 (RCW49) and may account for up to 30\approx 30 per cent of the total flux density observed at 31 GHz. Here, the dust emissivity of the excess emission is 13.6±4.2μ13.6\pm4.2 \muK (MJy/sr)1^{-1} and is within the range observed at high Galactic latitudes. Low level polarised emission was observed in all six sources with polarisation fractions in the range 0.30.60.3-0.6 per cent. This is likely to be mainly due to instrumental leakage and is therefore upper an upper limit to the free-free polarisation. It corresponds to an upper limit of 1\sim1 per cent for the polarisation of anomalous emission.Comment: Accepted in MNRAS. 12 pages, 10 figures, 5 table

    Precision Charmonium Spectroscopy From Lattice QCD

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    We present results for Charmonium spectroscopy using Non-Relativistic QCD (NRQCD). For the NRQCD action the leading order spin-dependent and next to leading order spin-independent interactions have been included with tadpole-improved coefficients. We use multi-exponential fits to multiple correlation functions to extract ground and excited SS states. Splittings between the lowest SS, PP and DD states are given and we have accurate values for the SS state hyperfine splitting and the χc\chi_c fine structure. Agreement with experiment is good - the remaining systematic errors are discussed.Comment: 23 pages uuencoded latex file. Contains figures in late
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