Non-perturbative pion matrix element of a twist-2 operator from the lattice

We give a continuum limit value of the lowest moment of a twist-2 operator in pion states from non-perturbative lattice calculations. We find that the non-perturbatively obtained renormalization group invariant matrix element is , which corresponds to . In obtaining the renormalization group invariant matrix element, we have controlled important systematic errors that appear in typical lattice simulations, such as non-perturbative renormalization, finite size effects and effects of a non-vanishing lattice spacing. The crucial limitation of our calculation is the use of the quenched approximation. Another question that remains not fully clarified is the chiral extrapolation of the numerical data.Received: 28 October 2004, Published online: 4 February 2005PACS: 11.15.Ha, 12.38.Gc     

Search for nearly mass-degenerate charginos and neutralinos at LEP

A search was performed for charginos with masses close to the mass of the lightest neutralino in collisions at centre-of-mass energies of 189-209 GeV recorded by the OPAL detector at LEP. Events were selected if they had an observed high-energy photon from initial state radiation, reducing the dominant background from two-photon scattering to a negligible level. No significant excess over Standard Model expectations has been observed in the analysed data set corresponding to an integrated luminosity of 570 pb^-1. Upper limits were derived on the chargino pair-production cross-section, and lower limits on the chargino mass were derived in the context of the Minimal Supersymmetric Extension of the Standard Model for the gravity- and anomaly-mediated Supersymmetry breaking scenarios.Received: 26 July 2002, Published online: 11 July 2003     

尿多胺含量与血液系统恶性肿瘤关系研究 Ⅱ、CGC-FID测定尿中多胺及临床中应用

本文报道采用硅胶预柱快速分离干扰杂质后用CGC-FID法测定尿中多胺。最低极限可测到1nmol。该法快速、灵敏、重现性好、所得回收率高、可用于临床诊断。     

Study of ATLAS sensitivity to FCNC top decays

The ATLAS experiment sensitivity to top quark flavour changing neutral current (FCNC) decays was studied at LHC using tt̄ events. While one of the top quarks is expected to follow the dominant Standard Model decay t→bW, the other decays through a FCNC channel, i.e. t→Zu(c), t→γu(c) or t→gu(c). Different types of analyses, applied to each FCNC decay mode, were compared. The FCNC branching ratio sensitivity (assuming a 5σ signal significance) and 95% confidence level limits on the branching ratios (in the hypothesis of signal absence) were obtained.     

Observation of modulated spontaneous emission of Rhodamine 6G in low refractive index contrast 1D-periodic gelatin film

The modulation of the spontaneous emission of Rhodamine 6G has been observed in one-dimensional periodic dielectric structure of dichromated gelatin film with refractive index contrast as low as 0.01. The spontaneous emission is enhanced at the band edges and inhibits in the band gap, which agree well with the theoretical analysis on the redistribution of the fractional local density of optical states.     

Update of the global electroweak fit and constraints on two-Higgs-doublet models

We present an update of the global fit of the Standard Model electroweak sector to latest experimental results. We include new kinematic top quark and W boson mass measurements from the LHC, a \(\sin \!^2\theta ^{\ell }_{\mathrm{eff}}\) result from the Tevatron, and a new evaluation of the hadronic contribution to \(\alpha (M_Z^2)\). We present tests of the internal consistency of the electroweak Standard Model and updated numerical predictions of key observables. The electroweak data combined with measurements of the Higgs boson coupling strengths and flavour physics observables are used to constrain parameters of two-Higgs-doublet models.     

Uniqueness Theorems for Holomorphic Curves with Hypersurfaces of Fermat–Waring Type

In this paper, we establish uniqueness theorems for holomorphic mappings from \(\mathbb C\) to \(P^N({\mathbb C}) \) for the case where the targets are not hyperplanes, but hypersurfaces of Fermat–Waring type.