30,578 research outputs found
Chiral-symmetry breaking in dual QCD
In the context of the formulation of QCD with dual potentials, we show that chiral-symmetry breaking occurs only in the confined state. Therefore, the transition temperature, beyond which chiral symmetry is restored, is the same as the deconfinement temperature. To carry out the calculation, it is necessary to couple quarks to dual gluons. We indicate how this is done (to lowest order in the magnetic coupling constant) and give the Feynman rules for quarkâdual-gluon vertices
A Constituent Quark Anti-Quark Effective Lagrangian Based on the Dual Superconducting Model of Long Distance QCD
We review the assumptions leading to the description of long distance QCD by
a Lagrangian density expressed in terms of dual potentials. We find the color
field distribution surrounding a quark anti-quark pair to first order in their
velocities. Using these distributions we eliminate the dual potentials from the
Lagrangian density and obtain an effective interaction Lagrangian depending only upon the quark
and anti-quark coordinates and velocities, valid to second order in their
velocities. We propose as the Lagrangian describing the long distance
interaction between constituent quarks. Elsewhere we have determined the two
free parameters in , and the string tension , by
fitting the 17 known levels of and systems. Here we use
at the classical level to calculate the leading Regge trajectory. We
obtain a trajectory which becomes linear at large with a slope , and for small the trajectory bends so
that there are no tachyons. For a constituent quark mass between 100 and 150
MeV this trajectory passes through the two known Regge recurrences of the
meson. In this paper, for simplicity of presentation, we have treated the
quarks as spin-zero particles.Comment: {\bf 32,UW/PT94-0
L^2 part of the heavy-quark potential from dual QCD and heavy-quark spectroscopy
We use the classical approximation to the dual QCD field equations to calculate the term in the heavy-quark potential that is proportional to angular momentum squared. This potential combined with the potentials obtained in our earlier work gives a result which is essentially the dual of the potential acting between a monopole-antimonopole pair carrying Dirac electric dipole moments and rotating in a relativistic superconductor. These potentials are used to fit the masses of the low-lying states of the ccÌ
and bbÌ
systems. The agreement, achieved with only four parameters, two of which are roughly determined in advance, is better than 1%. We also predict the masses of the lightest cbÌ
states
Static quark potential according to the dual-superconductor picture of QCD
We use the effective action describing long-range QCD, which predicts that QCD behaves as a dual superconductor, to derive the interaction energy between two heavy quarks as a function of separation. The dual-superconductor field equations are solved in an approximation in which the boundary between the superconducting vacuum and the region of normal vacuum surrounding the quarks is sharp. Further, non-Abelian effects are neglected. The resulting heavy-quark potential is linear in separation at large separation, and Coulomb-like at small separation. Overall it agrees very well with phenomenologically determined potentials
Quantized electric-flux-tube solutions to Yang-Mills theory
We suggest that long-distance Yang-Mills theory is more conveniently described in terms of electric rather than the customary magnetic vector potentials. On this basis we propose as an effective Lagrangian for this regime the most simple gauge-invariant (under the magnetic rather than electric gauge group) and Lorentz-invariant Lagrangian which yields a 1/q^4 gluon propagator in the Abelian limit. The resulting classical equations of motion have solutions corresponding to tubes of color electric flux quantized in units of e/2 (e is the Yang-Mills coupling constant). To exponential accuracy the electric color energy is contained in a cylinder of finite radius, showing that continuum Yang-Mills theory has excitations which are confined tubes of color electric flux. This is the criterion for electric confinement of color
Interaction between solitons in gauge theories
A systematic method for obtaining asymptotic multisoliton solutions in gauge theories is given. These solutions are used to investigate the interaction between vortex lines in type-I and type-II superconductors, reproducing the known behavior. The application to QCD flux tubes and glueballs obtained from the long-range effective Lagrangian yield the following results: (1) No long-range Van der Waalsâtype forces exist between these solitons in spite of the fact that the Abelian force law obtained from this model is a linear potential; (2) the interactions between flux tubes and between flux tubes and anti-flux-tubes are identical, being repulsive at long range and strongly attractive at short range. This behavior differs sharply from the superconductor case, and results from the differences between the gauge groups SU(2) and U(1)
The Legacy of ERA, Privatization and the Policy Ratchet
This article explores the ways in which the neo-liberal impetus toward the privatization of state schooling signalled in the Education Reform Act 1988 (ERA) has become embedded in the English school system. Four main points are made. First, that ERA itself was of huge strategic rather than substantive importance as far as privatization is concerned. Second, by tracing the lineage of privatization from ERA onwards a 'ratchet' effect of small and incremental policy moves can be identified, which have disseminated, embedded and naturalized privatization within public sector provision. Third, that while privatization has been taken up and taken much further by New Labour than it had been by the Conservatives there are differences between the two sets of governments in the role of privatization in education policy and the role of the state. Fourth, the participation of private providers in the planning and delivery of state services has put the private sector at the very heart of policy. At points the article draws upon interviews conducted with private sector providers. © 2008 Sage Publications
Producing the docile body: analysing Local Area Under-performance Inspection (LAUI)
Sir Michael Wilshaw, the head of the Office for Standards in Education (OfSTED), declared a 'new wave' of Local Area Under-performance Inspections (LAUI) of schools 'denying children the standard of education they deserve'. This paper examines how the threat of LAUI played out over three mathematics lessons taught by a teacher in her first year in the profession. A Foucauldian approach is mobilised with regard to disciplinary power and 'docile bodies'. The paper argues that, in the case in point, LAUI was a tool mediating performative conditions and, ultimately, the docile body. The paper will be of concern to policy sociologists, teachers, school leaders, and those interested in school inspection
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