On gauge independence in quantum gravity

We prove the gauge independence of the one-loop path integral for on-shell quantum gravity obtained in the framework of the modified geometric approach. We use a projector on pure gauge directions constructed via the quadratic form of the action. This enables us to formulate the proof entirely in terms of determinants of non-degenerate elliptic operators without reference to any renormalization procedure. The role of the rotation of the conformal factor in achieving gauge independence is discussed. Direct computations on CP² in a general three-parameter background gauge are presented. We comment on the gauge dependence of previous results by Ichinose.     

Cutoff Value for a Nutritional Indicator Related to Gait Independence in Elderly Fracture Patients: A Preliminary Study

Objective: Previous studies have reported the relationship between nutritional status and gait independence in elderly fracture patients. However, the degree to which nutritional indicators are related to gait independence is unclear. The purpose of this study is to calculate a cutoff value for a nutritional indicator related to gait independence in patients with hip and vertebral compression fractures. Method: This study included 69 patients (33 hip fracture, 36 vertebral compression fracture) who underwent rehabilitation at a convalescent rehabilitation ward. The relationships between nutritional indexes (Mini-Nutritional Assessment-Short Form [MNA^Ⓡ-SF] and skeletal muscle mass index [SMI] ) at admission and gait independence at discharge were analyzed using logistic regression. In addition, receiver operating characteristic analysis was performed to calculate a cutoff value that predicts gait independence. Results: Among the nutritional indicators used in this study, only MNA^Ⓡ-SF was significantly able to predict gait independence at discharge, and this association was maintained, even after adjustment for confounders. The calculated MNA^Ⓡ-SF cutoff values were 5.5 (sensitivity 100%, specificity 46.3%) and 7.5 points (sensitivity 67.9%, specificity 78.0%). Conclusion: This study suggests that MNA^Ⓡ-SF may be an index for predicting gait independence in patients with hip or vertebral compression fractures in the convalescent rehabilitation ward. The cutoff values calculated in this study were simple and useful index for physical therapists to interpret the results of MNA^Ⓡ-SF.     

Vector meson dominance model in γ+γ*(Q 2)→f(1270,2+)→ππ

Constructed is the vector dominance model for the γ+γ^*(Q ²)→f(1270,2⁺) process which is in good agreement with the experiment. We note that the experimental data do not require the consideration of the generalized vector dominance model. It is also shown that the vector dominance model (non-generalized) with the natural assumption of the vector meson-hadron scattering total cross section independence of vector meson helicity state describes well the total cross section of γγ^*→hardons process in the Regge region.     

Configuration mixing and total muon capture rates

We modify the Primakoff closure approximation to get independence on the mean neutrino energy and energy weighted sum rules are used for the corrective terms. A near model - independent discussion is then possible, and the total rates are shown to be a very sensitive tool to investigate configuration mixing of the target. Wild discrepancies with experiment would arise if the limit of pure jj or LS couplings are used for ¹²C, whereas the Cohen-Kurath wave function gives a very good result.     

Computing the Loewner Driving Process of Random Curves in the Half Plane

We simulate several models of random curves in the half plane and numerically compute the stochastic driving processes that produce the curves through the Loewner equation. Our models include models whose scaling limit is the Schramm-Loewner evolution (SLE) and models for which it is not. We study several tests of whether the driving process is Brownian motion, as it is for SLE. We find that testing only the normality of the process at a fixed time is not effective at determining if the random curves are an SLE. Tests that involve the independence of the increments of Brownian motion are much more effective. We also study the zipper algorithm for numerically computing the driving function of a simple curve. We give an implementation of this algorithm which runs in a time O(N ^1.35) rather than the usual O(N ²), where N is the number of points on the curve.     

Study of the luminescence of H2O and D2O ices induced by charged-particle bombardment

We measured the optical emission of H₂O and D₂O ices in visible region (300-500 nm) induced by energetic hydrogen ions (H⁺, H₂⁺, and H₃⁺) irradiation. Our analysis of the data of ion-stimulated luminescence (ISL) shows that all spectra of ISL emission are identical, independent of projectile. We show that all lines in the ISL emission spectrum may be assigned to decays from excited particles and/or fragments of H, H₂, OH, and H₂O. From the independence of emission spectrum on projectile we conclude that the final process causing the emissions may be attributed to the interaction between H⁺ (and/or H) and the water molecules.     

Does leading ln x resummation predict the rise of g 1 at small x?

We numerically analyse the evolution of the flavor non-singlet g ₁ structure function taking into account the all-order resummation of α_s ln² × terms which is expected to have much stronger effects than the DGLAP evolution in the small x region. We include a part of the next-to-leading logarithmic corrections coming from the resummed “coefficient function” which are not considered in the calculation of Blümlein and Vogt to respect the factorization scheme independence. It is pointed out that the resummed coefficient function gives unexpectedly large suppression factor over the experimentally accessible range of x and Q ². This fact implies that the next-to-leading logarithmic contributions are very important for the g ₁ structure function.     

Instantons and the hyperfine splitting ofB andB Smesons

In this short note we wish to point out that the instanton model, which was theoretically fascinating, has recently found application in explaining the hyperfine splitting of mesons and baryons. In particular, the flavour independence ofM _v ² -M _P ² (i.e. the squared mass difference of the vector and the pseudoscalar mesons), known to be constant for the strange and non-strange mesons in theu,d and the charm quark sectors, have recently been shown to be the same for the beauty sector through experiments. This flavour independence and the magnitude of the splitting agrees remarkably well with the instanton model.     

Consistency in NLO analyses of inclusive and semi-inclusive polarized DIS data

We perform a detailed study of the consistency between different sets of polarized deep inelastic scattering data and theory, from the standpoint of a next to leading order QCD global analysis, and following the criteria proposed by Collins and Pumplin. In face of recent suggestions that challenge the usual assumption about parent parton spin independence of unpolarized fragmentation functions, we specially focus on polarized semi-inclusive data. Received: 2 December 2002 / Revised version: 6 February 2003 / Published online: 31 March 2003 RID="a" ID="a" e-mail: sassot@df.uba.ar ^* Partially supported by Conicet and Fundación Antorchas     

氘-核自洽微观光学势的温度依赖性

本文在Skyrme相互作用参数与温度无关的假定下,利用Green函数的质量算符方法和半经典变分方法,推导了有限温度下氘-核自洽微观光学势的计算公式,计算和分析了在不同氘核入射能量下d+⁴⁰Ca和d+⁹⁰Zr光学势的温度依赖性。     

Hadron final states in deep-inelastic leptoproduction on nuclei

We discuss some aspects of the formation of inclusive hadron final states in deep-inelastic electro-, muo- and neutrinoproduction on nuclear targets.The inclusive final states are known to possess a remarkable Q² independence in interactions with free nucleons. Nevertheless, we prove that the nuclear spectra and mean multiplicities should have a rather specific and appreciable dependence on Q². In leptoproduction on heavy nuclei the yields of particles in nucleus fragmentation rise by a factor of two, as at the fixed energy transfer v one passes from incoherent scattering to diffraction scattering, and the total multiplicities change by 20–40%. The effects predicted seem to be detectable with the current and the near-future experimental facilities. Fermilab bubble chamber neutrino experiments and the coming SPS muon and neutrino experiments deserve special attention in this respect. We also comment on the possibilities offered by leptoproduction on nuclei for testing some absorption models.     

Explicit expressions for linearly independent spin eigenfunctions

Both the spin-free and the spin-dependent spin eigenfunctions with λ-double occupancy and their reverse relations are produced explicitly. The orthogonal spin coefficients for λ-double occupancy are just some linear sums of 2^λ orthogonal spin coefficients for zero-double occupancy. Their linear independence is shown.     

String tension in SU(3) lattice gauge theory

Wilson loop expectation values have been determined in SU(3) lattice gauge theory without fermions using Monte Carlo methods and considering lattices of up to 10⁴ sites. A heat bath technique has been developed in order to enhance the statistical independence of successive lattice configurations.     

Avoided level crossings and pair production in strong Coulomb fields

Generalising previous work on static strong Coulomb fields to the time-dependent case, we propose an alternative e ⁺ e ^- -pair production mechanism relying on avoided crossing transitions between positive and negative energy states. The resulting essential independence on the details of the collision process nicely matches experimental findings.     

General covariance of the non-abelian DBI-action: checks and balances

We perform three tests on our proposal to implement diffeomorphism invariance in the non-abelian D0-brane DBI action as a base-point independence constraint between matrix Riemann normal coordinate systems. First, we show that T-duality along an isometry correctly interchanges the potential and kinetic terms in the action. Second, we show that the method to impose base-point independence using an auxiliary dN²-dimensional nonlinear sigma model also works for metrics which are curved along the brane, provided a physical gauge choice is made at the end. Third, we show that without alteration this method is applicable to higher order in velocities. Testing specifically to order 4, we elucidate the range of validity of the symmetrized trace approximation to the non-abelian DBI action.     

Confirmation of temperature independence in the fluorescence lifetime of the P0 → F2 transition in praseodymium-doped fluoride glass

The dependence of the fluorescence lifetime from the ³P₀ → ³F₂ transition in praseodymium-doped fluoride glass as a function of dopant concentration and temperature was investigated. It was found that the fluorescence lifetime at the concentration of 7000 ppm was constant with temperature, confirming the prediction of temperature independence in the lifetime for this transition in Pr³⁺-doped ZBLAN glass.     

Measurement of the branching fractions and forward-backward asymmetries of the Z0 into light quarks

Using approximately 4.3 million hadronic Z⁰ decays collected with the OPAL detector at LEP between 1990 and 1995, we measure the branching fractions of the Z⁰ into up-type and down-type light quarks, Rq, and the forwardbackward asymmetries, A_FB(q), using high-momentum stable particles as a tag. Adopting a method that employs double tagged events to determine the flavour tagging efficiencies, and assuming the flavour independence of strong interactions and SU(2) isospin symmetry, we measure:     

A simple model for the velocity modulation detection technique of molecular ions

We present a simple model to describe the line-profile of velocity modulated ions. This model is based on Langevin's theory of the mobility and on the independence of the electric field strength on the discharge current in the ideal positive column. A comparison of time constants responsible for the drift of the ions, the concentration, and the ignition and extinction of the discharge itself is essential for a rough understanding of the velocity modulation. The behaviour of H₃O⁺ ions in an ac glow discharge was examined. Under our experimental conditions the line-profile can be explained by a temporal dependence of the velocity which is close to a square-wave. Due to this particular temporal dependence the amplitude of the signal only depends on the concentration modulation, while the line-shape is a simple difference line-profile.     

States on Symmetric Logics: Conditional Probability and Independence. II

We study the notions of conditional probabilities, independence and ε-independence for states on symmetric logics. We prove that a non-atomic state on the logic with the Lyapunov’s property is determined by its specification of independent events. We present the examples of (1) Δ-subadditive but is not subadditive and (2) two-valued non Δ-subadditive states on symmetric logic. We investigate the independence relation transitivity for a Δ-subadditive state. We also study continuity properties of conditional probabilities and ε-independence relation with respect to natural pseudometric for Δ-subadditive state. Finally, we pose two open problems.     

Remarks on Independent Value Model

By nonperturbative investigation of the generating functional for simple ⁴ model without gradient term we have shown that triviality of the model (independence of the result on the coupling) may be a perturbative calculation relict.