927 research outputs found
The Background Field Method and the Linearization Problem for Poisson Manifolds
The background field method (BFM) for the Poisson Sigma Model (PSM) is
studied as an example of the application of the BFM technique to open gauge
algebras. The relationship with Seiberg-Witten maps arising in non-commutative
gauge theories is clarified. It is shown that the implementation of the BFM for
the PSM in the Batalin-Vilkovisky formalism is equivalent to the solution of a
generalized linearization problem (in the formal sense) for Poisson structures
in the presence of gauge fields. Sufficient conditions for the existence of a
solution and a constructive method to derive it are presented.Comment: 33 pp. LaTex, references and comments adde
Super Background Field Method for N=2 SYM
The implementation of the Background Field Method (BFM) for quantum field
theories is analysed within the Batalin-Vilkovisky (BV) formalism. We provide a
systematic way of constructing general splittings of the fields into classical
and quantum parts, such that the background transformations of the quantum
fields are linear in the quantum variables. This leads to linear Ward-Takahashi
identities for the background invariance and to great simplifications in
multiloop computations. In addition, the gauge fixing is obtained by means of
(anti)canonical transformations generated by the gauge-fixing fermion. Within
this framework we derive the BFM for the N=2 Super-Yang-Mills theory in the
Wess-Zumino gauge viewed as the twisted version of Donaldson-Witten topological
gauge theory. We obtain the background transformations for the full BRST
differential of N=2 Super-Yang-Mills (including gauge transformations, SUSY
transformations and translations). The BFM permits all observables of the
supersymmetric theory to be identified easily by computing the equivariant
cohomology of the topological theory. These results should be regarded as a
step towards the construction of a super BFM for the Minimal Supersymmetric
Standard Model.Comment: 34 pages, Latex, JHEP3.cl
Comments on the Equivalence between Chern-Simons Theory and Topological Massive Yang-Mills Theory in 3D
The classical formal equivalence upon a redefinition of the gauge connection
between Chern-Simons theory and topological massive Yang-Mills theory in
three-dimensional Euclidean space-time is analyzed at the quantum level within
the BRST formulation of the Equivalence Theorem. The parameter controlling the
change in the gauge connection is the inverse of the topological
mass. The BRST differential associated with the gauge connection redefinition
is derived and the corresponding Slavnov-Taylor (ST) identities are proven to
be anomaly-free. The Green functions of local operators constructed only from
the (-dependent) transformed gauge connection, as well as those of
BRST invariant operators, are shown to be independent of the parameter
, as a consequence of the validity of the ST identities. The relevance
of the antighost-ghost fields, needed to take into account at the quantum level
the Jacobian of the change in the gauge connection, is analyzed. Their role in
the identification of the physical states of the model within conventional
perturbative gauge theory is discussed.Comment: 19 pages, LATEX, to appear in Journal of High Energy Physic
Algebraic Properties of BRST Coupled Doublets
We characterize the dependence on doublets of the cohomology of an arbitrary
nilpotent differential s (including BRST differentials and classical linearized
Slavnov-Taylor (ST) operators) in terms of the cohomology of the
doublets-independent component of s. All cohomologies are computed in the space
of local integrated formal power series. We drop the usual assumption that the
counting operator for the doublets commutes with s (decoupled doublets) and
discuss the general case where the counting operator does not commute with s
(coupled doublets). The results are purely algebraic and do not rely on
power-counting arguments.Comment: Some explanations enlarged, references adde
Renormalization of the Yang-Mills theory in the ambiguity-free gauge
The renormalization procedure for the Yang-Mills theory in the gauge free of
the Gribov ambiguity is constructed. It is shown that all the ultraviolet
infinities may be removed by renormalization of the parameters entering the
classical Lagrangian and the local redefinition of the fields.Comment: 20 pages. Some explanations extended, one reference added. Final
version published in the journa
Higher-order non-symmetric counterterms in pure Yang-Mills theory
We analyze the restoration of the Slavnov-Taylor (ST) identities for pure
massless Yang-Mills theory in the Landau gauge within the BPHZL renormalization
scheme with IR regulator. We obtain the most general form of the action-like
part of the symmetric regularized action, obeying the relevant ST identities
and all other relevant symmetries of the model, to all orders in the loop
expansion. We also give a cohomological characterization of the fulfillment of
BPHZL IR power-counting criterion, guaranteeing the existence of the limit
where the IR regulator goes to zero. The technique analyzed in this paper is
needed in the study of the restoration of the ST identities for those models,
like the MSSM, where massless particles are present and no invariant
regularization scheme is known to preserve the full set of ST identities of the
theory.Comment: Final version published in the journa
Preference of farmers towards private and public extension services
The main purpose of this study was to know the preference of farmers for different services provided by private and public extension agencies. In recent times involvement of private extension agencies has been increased in agricultural sector and up to some extent it has sidelined the public extension agencies, but public extension agencies have potential to do better and to reach farmers at their best. In view of this, present study was undertaken to find out the farmers’ preference towards public and private extension services in Ambala, Kurukshetra, Karnal, Hisar and Fatehabad districts of Haryana state. From each district two blocks were selected randomly and from each block two villages were selected. A manageable size of 10 farmers was selected from each village thus making total sample size of 200 farmers. Various aspects related to agricultural services provided by both public and private agencies were identified and response were obtained by putting a tick mark as per farmers’ preference for private and public agencies. On the basis of statistical tools like rank and mean score, results showed that farmers had great preference for ‘Input supply’ in private extension as compared to public extension followed by ‘Infrastructure facilities’. While for ‘Consultancy and diagnosis services’, ‘Information’ and ‘Technical services’, public extension was preferred as over the private extension
Slavnov-Taylor Parameterization for the Quantum Restoration of BRST Symmetries in Anomaly-Free Gauge Theories
It is shown that the problem of the recursive restoration of the
Slavnov-Taylor (ST) identities at the quantum level for anomaly-free gauge
theories is equivalent to the problem of parameterizing the local approximation
to the quantum effective action in terms of ST functionals, associated with the
cohomology classes of the classical linearized ST operator. The ST functionals
of dimension <=4 correspond to the invariant counterterms, those of dimension
>4 generate the non-symmetric counterterms upon projection on the action-like
sector. At orders higher than one in the loop expansion there are additional
contributions to the non-invariant counterterms, arising from known lower order
terms. They can also be parameterized by using the ST functionals. We apply the
method to Yang-Mills theory in the Landau gauge with an explicit mass term
introduced in a BRST-invariant way via a BRST doublet. Despite being
non-unitary, this model provides a good example where the method devised in the
paper can be applied to derive the most general solution for the action-like
part of the quantum effective action, compatible with the fulfillment of the ST
identities and the other relevant symmetries of the model, to all orders in the
loop expansion. The full dependence of the solution on the normalization
conditions is given.Comment: 23 pages. Final version published in the journa
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