Sökresultat

SU(2) lattice gauge theory in three dimensions is investigated on a 162×32 lattice. We find that R>×T Wilson loops are well described by a simple string theory for β in the (approximate) scaling region.

Recent SU(3) lattice Monte Carlo data (244 and 164) are analyzed in terms of a simple string model. Good agreement is found. Observed similarities between SU(3) and three-dimensional SU(2) indicate that the string theory is indeed an effective one.

Existing bag-model calculations for the masses of lowest-lying glueball states are extended and reviewed and compared to the present lattice Monte Carlo calculations. The predicted spectra agree remarkably well.

We consider SU(2) lattice gauge theory in three dimensions. The Wilson loops are found to be well described by a simple string model in the approximate scaling region.

Phenomenological consequences of a recently improved and unified study of the lowestlying hadrons in the MIT Bag model are explored. In contrast to earlier fits we find the new values for the Bag constant B1/4(200-230 MeV) and the hadronic radii R0(≈3.2 GeV-1) to be consistent with present estimates of the gluon condensate {Mathematical expression}, the Hagedorn temperature TH and experimental hyp

An effective spin-dependent interaction Hamiltonian for low-lying gluon modes is calculated to O(±s) in the MIT bag model. We give expressions for the energy shifts of low-lying glueballs.

We present a consistent and unified study of the spectrum of low-lying mesons, baryons, and glueballs using the MIT bag model, incorporating several improvements in the model. We correct for the center-of-mass motion, use a running coupling αs(R), include self-energy terms for quarks and gluons confined in a cavity, and get the bag constant from a model of the QCD vacuum. Our fit to the meson and

It is argued semiquantitatively that the magnetic instability of the perturbative QCD vacuum leads to the formation of a Bose-Einstein condensate that locally can be described as a JPC=0++ gluon color-singlet bound state of "glueball." We also indicate how this result might be obtained by a more rigorous field-theoretical treatment. A general discussion of the global properties of the "glueball va

Mellan 16 februari och 22 mars 2017 genomfördes 24 mätningar av finfraktionen (PM2.5) och grovfraktionen (PM10 – PM2.5) av grundämnen i luftburna partiklar på mätstationerna i Stadshuset och Lundåkrahamnen i Landskrona. Detta gjordes som ett led i att kontrollera luftkvaliten i Landskrona stad, särskilt med tanke på industrierna i Landskrona, som tidigare har givit höga halter av framförallt metal

We claim that experimental meson spectroscopy now requires the existence of constituent gluons. Drawing from several models, we study the number of mesons with given quantum numbers that can be expected in a given mass range, concentrating on pseudoscalars below 2 GeV. Counting only quark-antiquark states gives fewer mesons than are now seen, but including gluon degrees of freedom so that glueball

Methods for computing loop diagrams in confined scalar and gauge theories are developed. We construct propagators with different types of boundary conditions in boxes (rectangular cavities) using the method of image charges, which allows for a separation of the short-distance singularities. The techniques are illustrated by a calculation of the Casimir effect in a box using a covariant gauge, and

The postulate that ordinary hadrons contain intrinsic charm-quark states (such as |uudcc» in the proton) at the 1% level is shown to explain two sets of unexpected experimental results: (1) the copious diffractive production of charmed hadrons at large longitudinal momentum in high-energy proton-nucleon and pion-nucleon collisions, and (2) the anomalously large number of same-sign dimuon events ob

Leptospirosis is a zoonotic disease found wherever human is in direct or indirect contact with contaminated water and environment. Considering the increasing number of cases of this disease in the northern part of Iran, identifying areas characterized by high disease incidence risk can help policy-makers develop strategies to prevent its further spread. This study presents an approach for generati

Recent data give unexpectedly large cross-sections for charmed particle production at high xF in hadron collisions. This may imply that the proton has a non-negligible uudcc Fock component. The interesting consequences of such a hypothesis are explored.

We consider hadron production in deep inelastic scattering of electrons on photons. 1. (i)Exploiting the leading order QCD corrections due to gluon bremsstrahlung we find that the photon structure functions rapidly approach their asymptotic form which can be calculated in QCD. 2. (ii)Replacing QCD by a theory with a fixed quark-gluon coupling constant (scalar or abelian gluons) gives dramatic chan

We study deep inelastic scattering of an electron or positron on an almost real photon target in the reaction e+e− → e+e− + hadrons with C = +, where one e+ or e− is scattered at small or zero angle, yielding a virtual photon γ(k), k2 ∼ O(−me2). The other e− or e+ scatters on this virtual photon, emerging at large angle. We emphasize particularly: (i) the pointlike QCD contribution to the structur

We present a simple physical model of a nonperturbative gluon jet. The gluon fragments into isoscalar clusters in a cascade fashion. The primary mesons produced are η, η′, ω, φ (and states of bound glue). The experimental consequences of the model are dramatic, allowing a clear test.