1,748 research outputs found
Soft masses in superstring models with anomalous U(1) symmetries
We analyze the general structure of soft scalar masses emerging in
superstring models involving anomalous U(1) symmetries, with the aim of
characterizing more systematically the circumstances under which they can
happen to be flavor universal. We consider both heterotic orbifold and
intersecting brane models, possibly with several anomalous and non-anomalous
spontaneously broken U(1) symmetries. The hidden sector is assumed to consist
of the universal dilaton, Kahler class and complex structure moduli, which are
supposed to break supersymmetry, and a minimal set of Higgs fields which
compensate the Fayet-Iliopoulos terms. We leave the superpotential that is
supposed to stabilize the hidden sector fields unspecified, but we carefully
take into account the relations implied by gauge invariance and the constraints
required for the existence of a metastable vacuum with vanishing cosmological
constant. The results are parametrized in terms of a constrained Goldstino
direction, suitably defined effective modular weights, and the U(1) charges and
shifts. We show that the effect induced by vector multiplets strongly depends
on the functional form of the Kahler potential for the Higgs fields. We find in
particular that whenever these are charged matter fields, like in heterotic
models, the effect is non-trivial, whereas when they are shifting moduli
fields, like in certain intersecting brane models, the effect may vanish.Comment: 35 pages, LaTe
Remarks on twisted theories with matter
We investigate some aspects of N=2 twisted theories with matter
hypermultiplets in the fundamental representation of the gauge group. A
consistent formulation of these theories on a general four-manifold requires
turning on a particular magnetic flux, which we write down explicitly in the
case of SU(2k). We obtain the blowup formula and show that the blowup function
is given by a hyperelliptic sigma-function with singular characteristic. We
compute the contact terms and find, as a corollary, interesting identities
between hyperelliptic Theta functions.Comment: 18 pages, harvmac, one figur
Constraints for the existence of flat and stable non-supersymmetric vacua in supergravity
We further develop on the study of the conditions for the existence of
locally stable non-supersymmetric vacua with vanishing cosmological constant in
supergravity models involving only chiral superfields. Starting from the two
necessary conditions for flatness and stability derived in a previous paper
(which involve the Kahler metric and its Riemann tensor contracted with the
supersymmetry breaking auxiliary fields) we show that the implications of these
constraints can be worked out exactly not only for factorizable scalar
manifolds, but also for symmetric coset manifolds. In both cases, the
conditions imply a strong restriction on the Kahler geometry and constrain the
vector of auxiliary fields defining the Goldstino direction to lie in a certain
cone. We then apply these results to the various homogeneous coset manifolds
spanned by the moduli and untwisted matter fields arising in string
compactifications, and discuss their implications. Finally, we also discuss
what can be said for completely arbitrary scalar manifolds, and derive in this
more general case some explicit but weaker restrictions on the Kahler geometry.Comment: 22 pages, Latex, no figure
Minimal Stability in Maximal Supergravity
Recently, it has been shown that maximal supergravity allows for
non-supersymmetric AdS critical points that are perturbatively stable. We
investigate this phenomenon of stability without supersymmetry from the
sGoldstino point of view. In particular, we calculate the projection of the
mass matrix onto the sGoldstino directions, and derive the necessary conditions
for stability. Indeed we find a narrow window allowing for stable SUSY breaking
points. As a by-product of our analysis, we find that it seems impossible to
perturb supersymmetric critical points into non-supersymmetric ones: there is a
minimal amount of SUSY breaking in maximal supergravity.Comment: 27 pages, 1 figure. v2: two typos corrected, published versio
GP Financial Management Capacity and PRI Financial Management Reform Efforts in West Bengal
The State of West Bengal in its Annual Financial Statement of 2009-2010 called for “decentralization with accountability.” In addition to an expanded welfare system and the promotion of self-reliance at the local level, the State has been concerned with improving livelihoods through significantly enhanced funding to its local governments. To be effective, decentralization should move to the level of villages in rural areas in addition to accommodating urban municipalities. The Government of West Bengal (GOWB) has a strong interest in increasing the service delivery to constituents and has encouraged development in the area of financial management by providing incentives, training, computerization and the dissemination of good practice information for rural local governments (PRIs) in order to advance such delivery. This report provides a detailed assessment of the current state of budgeting and financial management capacity of the GOWB PRIs, an assessment of PRI financial management reforms, and focused attention to the capacity of the GPs to manage budgets and fiscal flow. Results from this work support development of a new grant program. The report also highlights budgeting and financial management issues relevant to creating an efficient flow of funds in such a grant program, given the capacity witnessed in GOWB rural local governments. Also, benchmarks that might be considered in a new grant program are provided
GP Financial Management Capacity and PRI Financial Management Reform Efforts in West Bengal
The State of West Bengal in its Annual Financial Statement of 2009-2010 called for “decentralization with accountability.” In addition to an expanded welfare system and the promotion of self-reliance at the local level, the State has been concerned with improving livelihoods through significantly enhanced funding to its local governments. To be effective, decentralization should move to the level of villages in rural areas in addition to accommodating urban municipalities. The Government of West Bengal (GOWB) has a strong interest in increasing the service delivery to constituents and has encouraged development in the area of financial management by providing incentives, training, computerization and the dissemination of good practice information for rural local governments (PRIs) in order to advance such delivery. This report provides a detailed assessment of the current state of budgeting and financial management capacity of the GOWB PRIs, an assessment of PRI financial management reforms, and focused attention to the capacity of the GPs to manage budgets and fiscal flow. Results from this work support development of a new grant program. The report also highlights budgeting and financial management issues relevant to creating an efficient flow of funds in such a grant program, given the capacity witnessed in GOWB rural local governments. Also, benchmarks that might be considered in a new grant program are provided
An international perspective on the determinants of local government fragmentation
The main questions addressed in this paper are the identification of the main determinants of jurisdictional fragmentation as presently observed across countries and how well those findings line up with the predictions of the expanded standard model of optimal jurisdiction size. To our knowledge, to date, there does not exit a rigorous study analyzing the cross-country determinants of fragmentation in the way this issue has been previously analyzed for some particular countries. At the outset, country fixed effects can be expected to loom large and powerful. Each country with its own history conditioned by a myriad of details, including colonial legacies, geography or ethnic and linguistic fragmentation, are likely to have contributed to heterogeneous levels of fragmentation. These factors could all be summarized in what is often termed the long shadow or the “dead hand” of history. Indeed, some countries may still have the same vertical structure of government that they had many decades ago. But there are also many countries that have changed their governmental structures over the years. So in this paper we would like to find out what may the common determinants that have led to those changes, and also perhaps to help us better understand if those common determinants can also be used to explain why other countries have changed so little. The rest of this paper is organized as follows. In section 2 we offer a simple extension of the conventional model for optimal jurisdiction size. In section 3 we review the literature on government fragmentation and its impact. In section 4 we outline the empirical model proposed for the analysis of jurisdictional fragmentation. In section 5 we present the results from our estimations. We conclude in section 6
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