825 research outputs found
Study of the Leutwyler-Smilga regimes: Lessons for full QCD simulations
Some key points out of my recent study of the characteristic features of the
small (), intermediate () and large ()
Leutwyler-Smilga regimes for QCD-type theories in a finite volume () are presented, and a few immediate consequences for full QCD
simulations are discussed.Comment: Lattice 2000 (Topology and Confinement), 4 pages, 4 figures
comprising 16 plots: cosmetic change
Current algebra derivation of temperature dependence of hadron couplings with currents
The vector and the axial-vector meson couplings with the vector and the
axial-vector currents respectively at finite temperature have been obtained in
Ref. \cite{Mallik} by calculating all the relevant one-loop Feynman graphs with
vertices obtained from the effective chiral Lagrangian. On the other hand, the
same couplings were also derived in Ref.\cite{Ioffe1} by applying the method of
current algebra and the hypothesis of partial conservation of axial-vector
current (PCAC). The latter method appears to miss certain terms; in the case of
the vector meson coupling with the vector current, for example, a term
containing the coupling is missed. A similar situation would
also appear for the nucleon coupling with the nucleon current. In this note we
resolve these differences.Comment: 7 pages, 2 eps figure
Lattice QCD data versus Chiral Perturbation Theory: the case of
I present a selection of recent lattice data by major collaborations for the
pseudo-Goldstone boson masses in full () QCD, where the valence quarks
are chosen exactly degenerate with the sea quarks. At least the more chiral
points should be consistent with Chiral Perturbation Theory for the latter to
be useful in extrapolating to physical masses. Perspectives to reliably
determine NLO Gasser-Leutwyler coefficients are discussed.Comment: 3 pages, 4 figures, ICHEP 2002, v2: one statement clarified, one ref.
adde
Strong Interactions at Low Energy
The lectures review some of the basic concepts relevant for an understanding
of the low energy properties of the strong interactions: chiral symmetry,
spontaneous symmetry breakdown, Goldstone bosons, quark condensate. The
effective field theory used to analyze the low energy structure is briefly
sketched. As an illustration, I discuss the implications of the recent data on
the decay for the magnitude of the quark condensate.Comment: Lectures given at the school of physics "Understanding the structure
of hadrons", Prague, July 2001, 20 p
Chiral Perturbation Theory for the Quenched Approximation of QCD
[This version is a minor revision of a previously submitted preprint. Only
references have been changed.] We describe a technique for constructing the
effective chiral theory for quenched QCD. The effective theory which results is
a lagrangian one, with a graded symmetry group which mixes Goldstone bosons and
fermions, and with a definite (though slightly peculiar) set of Feynman rules.
The straightforward application of these rules gives automatic cancellation of
diagrams which would arise from virtual quark loops. The techniques are used to
calculate chiral logarithms in , , , and the ratio of
to . The leading
finite-volume corrections to these quantities are also computed. Problems for
future study are described.Comment: 14 page
Holography with Gravitational Chern-Simons Term
The holographic description in the presence of gravitational Chern-Simons
term is studied. The modified gravitational equations are integrated by using
the Fefferman-Graham expansion and the holographic stress-energy tensor is
identified. The stress-energy tensor has both conformal anomaly and
gravitational or, if re-formulated in terms of the zweibein, Lorentz anomaly.
We comment on the structure of anomalies in two dimensions and show that the
two-dimensional stress-energy tensor can be reproduced by integrating the
conformal and gravitational anomalies. We study the black hole entropy in
theories with a gravitational Chern-Simons term and find that the usual
Bekenstein-Hawking entropy is modified. For the BTZ black hole the modification
is determined by area of the inner horizon. We show that the total entropy of
the BTZ black hole is precisely reproduced in a boundary CFT calculation using
the Cardy formula.Comment: 19 pages, Latex; v3: minor corrections, some clarification
Topology and pion correlators -- a study in the N_f=2 Schwinger model
I readdress the issue whether the topological charge of the gauge background
has an influence on a hadronic observable. To this end pion correlators in the
Schwinger model with 2 dynamical flavours are determined on subensembles with a
fixed topological charge. It turns out that the answer depends on a specific
function of the sea-quark mass and the box volume which is in close analogy to
the Leutwyler-Smilga parameter in full QCD.Comment: Lattice2001(confinement), 3 pages, 2 figure
Aspects of quark mass generation on a torus
In this talk we report on recent results for the quark propagator on a
compact manifold. The corresponding Dyson-Schwinger equations on a torus are
solved on volumes similar to the ones used in lattice calculations. The
quark-gluon interaction is fixed such that the lattice results are reproduced.
We discuss both the effects in the infinite volume/continuum limit as well as
effects when the volume is small.Comment: 3 pages, 3 figures; talk given by CF at QNP06, Madrid, June 200
The structure of teacher-specific intercultural competence: Empirical evidence on the 'Beliefs, Values, and Goals' dimension
The aim of this contribution is to identify the elements that are integral parts of a teacher-specific intercultural competence construct. In this paper, we focus on those facets of the construct that are considered to be rather value-laden and affectively tinged. Following the widely used theoretical model of teachersâ professional competencies developed by Baumert and Kunter (2013), we conceptually place these facets within the Beliefs, Values, & Goals dimension, and propose four core elements: (1) appreciation of cultural diversity; (2) ethno-relative worldview; (3) attitudes toward integration; and (4) identification with goals of intercultural education. In order to test the hypothesis that these four aspects represent one single overarching latent construct, we operationalized each with an appropriate scale and then scrutinized the instrumentsâ internal consistency, and convergent and factorial validity. The results suggest that our four scales have good internal consistencies (Cronbachâs alphas between .82 and .89), adhere to a one-factor structure (as demonstrated by Confirmatory Factor Analysis), and indicate one latent construct (RMSEA = 0.000; TLI = 1.004; CFI =
1.000; SRMR = .007). With these results, this paper presents a valid, contextually relevant new instrument to assess (pre-service) teachersâ beliefs, values and goals regarding intercultural education and contributes to resolving theoretical, methodological, and practical issues of research on intercultural competencies.+repphzhbib2018
Effective QCD Partition Function in Sectors with Non-Zero Topological Charge and Itzykson-Zuber Type Integral
It was conjectured by Jackson et.al. that the finite volume effective
partition function of QCD with the topological charge coincides with the
Itzyskon-Zuber type integral for rectangular matrices. In the
present article we give a proof of this conjecture, in which the original
Itzykson-Zuber integral is utilized.Comment: 7pages, LaTeX2
- âŠ