1,071 research outputs found

    Beautiful Baryons from Lattice QCD

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    We perform a lattice study of heavy baryons, containing one (Λb\Lambda_b) or two bb-quarks (Ξb\Xi_b). Using the quenched approximation we obtain for the mass of Λb\Lambda_b MΛb=5.728±0.144±0.018GeV. M_{\Lambda_b}= 5.728 \pm 0.144 \pm 0.018 {\rm GeV}. The mass splitting between the Λb\Lambda_b and the B-meson is found to increase by about 20\% if the light quark mass is varied from the chiral limit to the strange quark mass.Comment: 11 pages, Figures obtained upon request from [email protected]

    Heavy-light baryonic mass splittings from the lattice

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    We present lattice estimates of the mass of the heavy-light baryons Λb\Lambda_b and Ξb\Xi_b obtained using propagating heavy quarks. For Λb\Lambda_b our result is MΛb=5.728±0.144±0.018M_{\Lambda_b}=5.728 \pm 0.144 \pm 0.018 GeV, after extrapolation to the continuum limit and in the quenched approximation.Comment: 3 pages postscript, Contribution to Lattice'9

    A lattice NRQCD computation of the bag parameters for ΔB\Delta B = 2 operators

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    We present an update of our NRQCD calculation of BBB_B at ÎČ\beta=5.9 with increased statistics. We also discuss a calculation of BSB_S, which is relevant to the width difference in the Bs−BˉsB_s-\bar{B}_s mixing.Comment: LATTICE99 (Heavy Quarks), 3 pages, 2 figures, espcrc2.st

    Human chorionic gonadotropin isoforms in the diagnosis of ectopic pregnancy

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    This paper has set the scene for re-defining clinical chemistry data for the diagnosis of ectopic pregnancy. Indeed it has proved some assumptions on hCG levels to be false. Professor Iles was/is the principal investigator on these studies

    Adaptive Step Size for Hybrid Monte Carlo Algorithm

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    We implement an adaptive step size method for the Hybrid Monte Carlo a lgorithm. The adaptive step size is given by solving a symmetric error equation. An integr ator with such an adaptive step size is reversible. Although we observe appreciable variations of the step size, the overhead of the method exceeds its benefits. We propose an explanation for this phenomenon.Comment: 13 pages, 5 Postscript figures, late

    Ordering monomial factors of polynomials in the product representation

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    The numerical construction of polynomials in the product representation (as used for instance in variants of the multiboson technique) can become problematic if rounding errors induce an imprecise or even unstable evaluation of the polynomial. We give criteria to quantify the effects of these rounding errors on the computation of polynomials approximating the function 1/s1/s. We consider polynomials both in a real variable ss and in a Hermitian matrix. By investigating several ordering schemes for the monomials of these polynomials, we finally demonstrate that there exist orderings of the monomials that keep rounding errors at a tolerable level.Comment: Latex2e file, 7 figures, 32 page

    The Quest for Light Sea Quarks: Algorithms for the Future

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    As part of a systematic algorithm study, we present first results on a performance comparison between a multibosonic algorithm and the hybrid Monte Carlo algorithm as employed by the SESAM collaboration. The standard Wilson fermion action is used on 32*16^3 lattices at beta=5.5.Comment: LaTeX, 3 pages, Lattice2001(algorithms

    Anorectal manometry in children with defecation disorders BSPGHAN Motility Working Group consensus statement

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    Defecatory disorders in children, including chronic constipation (CC) and fecal incontinence (FI), are common conditions worldwide and have a significant impact on children, their families, and the healthcare system. Anorectal manometry (ARM) and high‐resolution anorectal manometry (HRAM) are relatively novel tools for the assessment of anal sphincter function and rectal sensation and have contributed significantly to improving the understanding of the anorectum as a functional unit. ARM has been recognized as the investigation of choice for adults with symptoms of defecation disorders, including fecal incontinence (FI), evacuation difficulties, and constipation. Although it is the gold standard tool in adults, it has yet to be formally accepted as a standardized diagnostic tool in the pediatric age, with limited knowledge regarding indications, protocol, and normal values. ARM/HRAM is slowly becoming recognized among pediatricians, but given that there are currently no agreed guidelines there is a risk that will lead to diversity in practice. The British Society of Paediatric Gastroenterology, Hepatology and Nutrition (BSPGHAN)—Motility Working Group (MWG) therefore has taken the opportunity to provide guidance on the use of ARM/HRAM in children with CC and/or FI

    Chiral Symmetry Versus the Lattice

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    After mentioning some of the difficulties arising in lattice gauge theory from chiral symmetry, I discuss one of the recent attempts to resolve these issues using fermionic surface states in an extra space-time dimension. This picture can be understood in terms of end states on a simple ladder molecule.Comment: Talk at the meeting "Computer simulations studies in condensed matter physics XIV" Athens, Georgia, Feb. 19-24, 2001. 14 page
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