6,439 research outputs found

    On Asymmetric Orbifolds and the D=5 No-modulus Supergravity

    Get PDF
    We examine whether any type II asymmetric orbifolds have the same massless spectrum as the dimensional reduction of D=5 simple supergravity, which, besides the eleven-dimensional supergravity, is the only known supergravity above four dimensions with no moduli. We attempt to construct such models by further twisting the orbifolds which yield D=4, N=4 pure supergravity to find that, unfortunately, none of the models have that spectrum. We provide supergravity arguments explaining why this is so. As a by-product, we list all possible momentum-winding lattices that give D=4, N=4 pure supergravity.Comment: 10 page

    Duality Symmetry of String Theory: A Worldsheet Perspective

    Get PDF
    We study duality and local symmetries of closed bosonic string from the perspectives of worldsheet approach in the phase space path integral formalism. It is shown that the Ward identities reflecting the local symmetries associated with massless excitations such as graviton and antisymmetric tensor can be cast in a duality covariant form. It is shown how the manifestly O(d,d) invariant Hamiltonian can be obtained in the Hassan-Sen toroidal compactification scheme, d being the number of compact dimensions. It is proposed that massive excited states possess a T-duality symmetry for constant (tensor) backgrounds. This conjecture is verified for the first massive level.Comment: 14 page

    Synthetic Grey Water Treatment Through FeCl3-Activated Carbon Obtained from Cotton Stalks and River Sand

    Get PDF
    The research objective was to reclaim greywater through simple, easily available, and cost-effective methods. For this purpose, an activated charcoal was prepared from biomass (cotton stalk) through the pyrolysis process and sand collected from river Indus. Both materials were subjected to separate columns and applied as filters. Whereas, the efficiency of both materials as filter media was analyzed on the synthetic grey water (SGW). The formulation of synthetic greywater was a complicated process because the selection of ingredients and their amount should not exceed from the real grey water. So, for the presence of fecal contamination, a small amount (10 ml L-1) of settled sewage was added to the distilled water, while to mimic the organic load, several chemical products of technical grade were also added. The physicochemical and microbiological characteristics of this SGW were tested before and after treatment. The results show that both mediums (AC and river sand) were very effective in the greywater treatment. The removal efficiency for BOD and COD was up to 91.2%, and 70% respectively. Similarly, the removal measure for turbidity was 91.3%. While the pH showed that the synthetic grey water was alkaline in nature with a value of 10 because the washing detergents used during the preparation of SGW, but after passing through both filter columns, pH was observed in between 7 and 8 units. Furthermore, the removal value examined after passing SGW from both columns for total coliforms was 46.87 CFU/100 ml from1500 CFU/100 ml

    Noncompact Symmetries in String Theory

    Get PDF
    Noncompact groups, similar to those that appeared in various supergravity theories in the 1970's, have been turning up in recent studies of string theory. First it was discovered that moduli spaces of toroidal compactification are given by noncompact groups modded out by their maximal compact subgroups and discrete duality groups. Then it was found that many other moduli spaces have analogous descriptions. More recently, noncompact group symmetries have turned up in effective actions used to study string cosmology and other classical configurations. This paper explores these noncompact groups in the case of toroidal compactification both from the viewpoint of low-energy effective field theory, using the method of dimensional reduction, and from the viewpoint of the string theory world sheet. The conclusion is that all these symmetries are intimately related. In particular, we find that Chern--Simons terms in the three-form field strength HμνρH_{\mu\nu\rho} play a crucial role.Comment: 40 pages, phyzzx, CALT-68-179

    Duality Transformations in Supersymmetric Yang-Mills Theories coupled to Supergravity,

    Get PDF
    We consider duality transformations in N=2, d=4 Yang--Mills theory coupled to N=2 supergravity. A symplectic and coordinate covariant framework is established, which allows one to discuss stringy `classical and quantum duality symmetries' (monodromies), incorporating T and S dualities. In particular, we shall be able to study theories (like N=2 heterotic strings) which are formulated in symplectic basis where a `holomorphic prepotential' F does not exist, and yet give general expressions for all relevant physical quantities. Duality transformations and symmetries for the N=1 matter coupled Yang--Mills supergravity system are also exhibited. The implications of duality symmetry on all N>2 extended supergravities are briefly mentioned. We finally give the general form of the central charge and the N=2 semiclassical spectrum of the dyonic BPS saturated states (as it comes by truncation of the N=4 spectrum).Comment: 41 pages, harvmac, no figures. References added, and minor printing error corrected

    Maria del Refugio Corral

    Get PDF
    Illustration: Monika Narain / Narration: Brandon Smith, Archan Das, Monika Narain, Hannah Xu and Krisha Patelhttps://digitalcommons.imsa.edu/spanish_v/1000/thumbnail.jp

    Peri-urbanism in globalizing India: a study of pollution, health and community awareness

    Get PDF
    This paper examines the intersection between environmental pollution and people's acknowledgements of, and responses to, health issues in Karhera, a former agricultural village situated between the rapidly expanding cities of New Delhi (India's capital) and Ghaziabad (an industrial district in Uttar Pradesh). A relational place-based view is integrated with an interpretive approach, highlighting the significance of place, people's emic experiences, and the creation of meaning through social interactions. Research included surveying 1788 households, in-depth interviews, participatory mapping exercises, and a review of media articles on environment, pollution, and health. Karhera experiences both domestic pollution, through the use of domestic waste water, or gandapani, for vegetable irrigation, and industrial pollution through factories' emissions into both the air and water. The paper shows that there is no uniform articulation of any environment/health threats associated with gandapani. Some people take preventative actions to avoid exposure while others do not acknowledge health implications. By contrast, industrial pollution is widely noted and frequently commented upon, but little collective action addresses this. The paper explores how the characteristics of Karhera, its heterogeneous population, diverse forms of environmental pollution, and broader governance processes, limit the potential for citizen action against pollution

    Summary of the Activities of the Working Group I on High Energy and Collider Physics

    Get PDF
    This is a summary of the projects undertaken by the Working Group I on High Energy Collider Physics at the Eighth Workshop on High Energy Physics Phenomenology (WHEPP8) held at the Indian Institute of Technology, Mumbai, January 5-16, 2004. The topics covered are (i) Higgs searches (ii) supersymmetry searches (iii) extra dimensions and (iv) linear collider.Comment: summary of Working Group I at the Eighth Workshop on High Energy Physics Phenomenology (WHEPP8), I.I.T., Mumbai, January 5-16, 200

    The D0 Run II Impact Parameter Trigger

    Full text link
    Many physics topics to be studied by the D0 experiment during Run II of the Fermilab Tevatron ppbar collider give rise to final states containing b--flavored particles. Examples include Higgs searches, top quark production and decay studies, and full reconstruction of B decays. The sensitivity to such modes has been significantly enhanced by the installation of a silicon based vertex detector as part of the DO detector upgrade for Run II. Interesting events must be identified initially in 100-200 microseconds to be available for later study. This paper describes custom electronics used in the DO trigger system to provide the real--time identification of events having tracks consistent with the decay of b--flavored particles.Comment: To be submitted to Nucl. Instrum. Methods A. 56 pages, 31 figure
    corecore