9,150 research outputs found
Modifications on nucleon parameters at finite temperature
Taking into account the additional operators coming up at finite temperature,
we investigate the mass and residue of the nucleon in the framework of thermal
QCD sum rules. We observe that the mass and residue of the nucleon are
initially insusceptible to increase of temperature, however after a certain
temperature, they start to fall increasing the temperature.Comment: 12 Pages, 4 Figures and 1 Tabl
Thermal behavior of the mass and residue of hyperons
We investigate the mass and residue of the , and
hyperons at finite temperature in the framework of thermal QCD sum rules. In
our calculation, we take into account the additional operators coming up at
finite temperature. We find the temperature-dependent continuum threshold for
each hyperon using the obtained sum rules for their mass and residue. The
numerical results demonstrate that the mass and residue of the particles under
consideration remain stable up to a certain temperature, after which they
decrease by increasing the temperature.Comment: 25Pages, 6 Figures and 2 Table
Quantum Chromodynamics with Many Flavors
We investigate the phase structure of lattice QCD for general number of
flavors . Based on numerical data combined with the results of the
perturbation theory we propose the following picture: When , there
is only one IR fixed point at vanishing gauge coupling, i.e., the theory in the
continuum limit is trivial. On the other hand, when , there
is a non-trivial fixed point. Therefore, the theory is non-trivial with
anomalous dimensions, however, without quark confinement. Theories which
satisfy both quark confinement and spontaneous chiral symmetry breaking in the
continuum limit exist only for .Comment: Talk presented by K. Kanaya at the 1997 Yukawa International Seminar
(YKIS'97) on ``Non-Perturbative QCD --- Structure of the QCD Vacuum ---'',
YITP, Kyoto, Japan, 2--12 Dec. 1997. To be published in the proceedings
[Prog. Theor. Phys. Suppl.
Evolving temporal fuzzy association rules from quantitative data with a multi-objective evolutionary algorithm
A novel method for mining association rules that are both quantitative and temporal using a multi-objective evolutionary algorithm is presented. This method successfully identifies numerous temporal association rules that occur more frequently in areas of a dataset with specific quantitative values represented with fuzzy sets. The novelty of this research lies in exploring the composition of quantitative and temporal fuzzy association rules and the approach of using a hybridisation of a multi-objective evolutionary algorithm with fuzzy sets. Results show the ability of a multi-objective evolutionary algorithm (NSGA-II) to evolve multiple target itemsets that have been augmented into synthetic datasets
Microsporidan Spores: Retention of Infectivity after Passage through the Gut of the Assassin Bug, Zelus exsanguis (Stal)
Thermal QCD Sum Rules Study of Vector Charmonium and Bottomonium States
We calculate the masses and leptonic decay constants of the heavy vector
quarkonia, and mesons at finite temperature. In particular,
considering the thermal spectral density as well as additional operators coming
up at finite temperature, the thermal QCD sum rules are acquired. Our numerical
calculations demonstrate that the masses and decay constants are insensitive to
the variation of temperature up to , however after this point,
they start to fall altering the temperature. At deconfinement temperature, the
decay constants attain roughly to 45% of their vacuum values, while the masses
are diminished about 12%, and 2.5% for and states,
respectively. The obtained results at zero temperature are in good consistency
with the existing experimental data as well as predictions of the other
nonperturbative models. Considerable decreasing in the values of the decay
constants can be considered as a sign of the quark gluon plasma phase
transition.Comment: 14 Pages, 8 Figures and 2 Table
Thomas-Fermi-Poisson theory of screening for latterally confined and unconfined two-dimensional electron systems in strong magnetic fields
We examine within the self-consistent Thomas-Fermi-Poisson approach the
low-temperature screening properties of a two-dimensional electron gas (2DEG)
subjected to strong perpendicular magnetic fields. Numerical results for the
unconfined 2DEG are compared with those for a simplified Hall bar geometry
realized by two different confinement models. It is shown that in the strongly
non-linear screening limit of zero temperature the total variation of the
screened potential is related by simple analytical expressions to the amplitude
of an applied harmonic modulation potential and to the strength of the magnetic
field.Comment: 12 pages, 12 figure
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