Filetype
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.
The origin of the observed scaling violations in inclusive e+e- annihilation is investigated. Perturbative jet evolution is not necessarily the only reason for scale breaking in the hadron spectra at present energies. Remnants of finite-transverse-momentum and mass effects are still important in nonperturbative, cascade-type, jet formation in the 10 GeV range. Heavy-quark fragmentation has a stron
Recent advances in coarse-grained lattice and off-lattice protein models are reviewed. The sequence dependence of thermodynamical folding properties are investigated and evidence for non-randomness of the binary sequences of good folders are discussed. Similar patterns for non-randomness are found for real proteins. Dynamical parameter MC methods, such as the tempering and multisequence algorithms
A neural network algorithm for finding tracks in high energy physics experiments is presented. The performance of the algorithm is explored on modest size samples with encouraging results. It is inherently parallel and thus suitable for execution on a conventional SIMD architecture. More important, it naturally lends itself to direct implementations in custom made hardware, which would permit real
An F77 package for feed-forward artificial neural network data processing, JETNET 3.0, is presented. It represents a substantial extension and generalization of an earlier release, JETNET 2.0. The package, which consists of a set of subroutines, is focused on multilayer perceptron architectures. As compared to earlier versions it contains a variety of minimization options, measures for monitoring
A neural network method for identifying the ancestor of a hadron jet is presented. The idea is to find an efficient mapping between certain observed hadronic kinematical variables and the quark-gluon identity. This is done with a neuronic expansion in terms of a network of sigmoidal functions using a gradient descent procedure, where the errors are back-propagated through the network. With this me
