16,566 research outputs found

    Comparing lattice Dirac operators with Random Matrix Theory

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    We study the eigenvalue spectrum of different lattice Dirac operators (staggered, fixed point, overlap) and discuss their dependence on the topological sectors. Although the model is 2D (the Schwinger model with massless fermions) our observations indicate possible problems in 4D applications. In particular misidentification of the smallest eigenvalues due to non-identification of the topological sector may hinder successful comparison with Random Matrix Theory (RMT).Comment: LATTICE99(topology and confinement), Latex2e using espcrc2.sty, 3 pages, 3 figure

    Electroweak Corrections to the Decays of Stop and Gluino

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    The electroweak corrections at the order of O(αewmt(b)2/mW2)O(\alpha_{ew}m_{t(b)}^2/m_W^2) to the partial widths of the t~2g~+t\tilde{t}_2 \to \tilde{g} + t and g~t~1+tˉ\tilde{g} \to \tilde{t}_1 + \bar{t} decays (depending on the masses of the particles involved) are investigated within the Supersymmetric Standard Model. The relative corrections can reach the value of 10% in some parameter space, which can be comparable with the corresponding QCD corrections. Therefore, they should be taken into account for the precise experimental measurement at future colliders.Comment: 15 pages, 5 figures, Physical Review D publication versio

    Refractometry of organosilica microspheres

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    The refractive index of novel organosilica (nano/micro)material is determined using two methods. The first method is based on analysis of optical extinction efficiency of organosilica beads versus wavelength, which is obtained by a standard laboratory spectrometer. The second method relies on the measurable trapping potential of these beads in the focused light beam (laser tweezers). Polystyrene beads were used to test these methods, and the determined dispersion curves of refractive index values have been found accurate. The refractive index of organosilica beads has been determined to range from 1.60-1.51 over the wavelength range of 300-1100 nm.Comment: 9 pages, 8 figure

    A systematic review and meta-analysis on acoustic voice parameters after uncomplicated thyroidectomy

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    BACKGROUND: Postthyroidectomy voice changes are common even without apparent laryngeal nerve injury. Our study evaluated the impact of open cervical thyroidectomy on five acoustic voice parameters in the early (< 3 months) and late (≥ 3 months) postoperative periods. METHODS: A systematic review was performed to identify studies that quantitatively assessed voice quality by acoustic voice analysis before and after thyroidectomy. Parameters included average fundamental frequency (F0 , Hz), jitter (%), shimmer (%), noise-to-harmonic ratio (NHR), and maximum phonation time (MPT) (in secs). Meta-analysis was performed using both fixed- and random-effects models. RESULTS: A total of 896 patients were analyzed. Relative to baseline, F0 significantly worsened in the early period (from 194.9 ± 34.9 Hz to 188.0 ± 34.0 Hz, P = 0.001). This was equivalent to a quarter-tone loss (P = 0.004). Shimmer (from 3.15 ± 1.59% to 3.19 ± 1.70%, P = 0.040) and MPT (from 17.9 secs to 16.7 secs, P = 0.046) also worsened in the early period, whereas jitter and NHR remained unchanged in the early and late periods. Males suffered greater deterioration in F0 (from 120.6 ± 18.8 Hz to 111.0 ± 18.5 Hz, P = 0.048) and in NHR (from 0.12 ± 0.02 to 0.16 ± 0.03, P = 0.019) than females in the early period. Four of the five acoustic parameters (F0 , jitter, shimmer, and NHR) significantly worsened after total thyroidectomy (TT) and not after lesser resection. CONCLUSION: F0 , shimmer, and MPT significantly worsened in the early and not in the late postoperative period. F0 impairment was perceptually significant. Males and those undergoing TT suffered greater voice impairment than their counterparts during the early period.postprin

    Single chargino production via gluon-gluon fusion in a supersymmetric theory with an explicit R-parity violation

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    We studied the production of single charginoχ~1±\tilde{\chi}_1^{\pm} accompanied by μ\mu^{\mp} lepton via gluon-gluon fusion at the LHC. The numerical analysis of their production rates is carried out in the mSUGRA scenario with some typical parameter sets. The results show that the cross sections of the χ~1±μ\tilde{\chi}_1^{\pm}\mu^{\mp} productions via gluon-gluon collision are in the order of 11021 \sim 10^{2} femto barn quantitatively at the CERN LHC, and can be competitive with production mechanism via quark-antiquark annihilation process.Comment: LaTex file, 18 pages, 4 EPS file

    A nondiagrammatic calculation of the Rho parameter from heavy fermions

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    A simple nondiagrammatic evaluation of the nondecoupling effect of heavy fermions on the Veltman's Rho parameter is presented in detail. This calculation is based on the path integral approach, the electroweak chiral Lagrangian formalism, and the Schwinger proper time method.Comment: 11 page
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