Search

Abstract: Should nature be supersymmetric, then it will be described by Quantum Supergravity at least in some energy regimes. The currently most advanced description of Quantum Supergravity and beyond is Superstring Theory/M-Theory in 10/11 dimensions. String Theory is a top-to-bottom approach to Quantum Supergravity in that it postulates a new object, the string, from which classical Supergravity emerges as a low energy limit. On the other hand, one may try more traditional bottom-to-top routes and apply the techniques of Quantum Field Theory. Loop Quantum Gravity (LQG) is a manifestly background independent and non-perturbative approach to the quantisation of classical General Relativity, however, so far mostly without supersymmetry. The main obstacle to the extension of the techniques of LQG to the quantisation of higher dimensional Supergravity is that LQG rests on a specific connection formulation of General Relativity which exists only in dimensions. In this Letter we introduce a new connection formulation of General Relativity which exists in all space–time dimensions. We show that all LQG techniques developed in can be transferred to the new variables in all dimensions and describe how they can be generalised to the new types of fields that appear in Supergravity theories as compared to standard matter, specifically Rarita–Schwinger and p-form gauge fields. [Copyright &y& Elsevier]

Abstract: General formulae for the soft SUSY breaking terms, valid in any SUGRA context, were derived in the mid-nineties. Since SUSY is not expected to have quantum anomalies, they should be valid in the quantum theory and be RG invariant down to the soft SUSY breaking scale. This observation enables us to give a uniform treatment of all phenomenological models for SUSY breaking and transmission, such as AMSB, GMSB, etc. In particular we find that the much discussed RG invariant formulae for soft SUSY breaking parameters in AMSB, effectively depend on a strong assumption of factorizability of the matter Kaehler metric. We then argue that there is no necessity for having ad hoc constructions such as mAMSB to counteract the negative squared slepton mass problem, since the natural framework that emerges in a sequestered model is one in which gaugino masses are as in AMSB, and the other soft terms are generated by RG running as in gaugino mediation. [Copyright &y& Elsevier]

Abstract: Apply the T-duality and smeared twist to the D3-brane solution one can construct the supergravity backgrounds which may dual to supersymmetric or non-supersymmetric non-commutative dipole field theory. We introduce D7-brane probe into the dual supergravity background to study the chiral dynamics and meson spectrum therein. We first find that the non-commutative dipole field does not induce the chiral symmetry breaking even if the supersymmetry was completely broken, contrast to the conventional believing that the chiral symmetry will be broken in the non-supersymmetric theory. Next, we find that the dipole field does not modify the meson spectrum in the supersymmetric theory while it will reduce the meson bound-state energy in the non-supersymmetric theory. We also evaluate the static quark–anti-quark potential and see that the dipole field has an effect to produce attractive force between the quark and anti-quark. [Copyright &y& Elsevier]

Abstract: If there are a large number of vacua, multi-inflation may be a more mediocre phenomenon rather than a single inflation. In the multi-inflation scenario, new inflation is most likely the last inflation, since its energy scale is naturally low. Furthermore, it may explain the observed spectral index of the cosmic microwave background radiations. We show, in this Letter, that a new inflation model proposed in supergravity accounts for all the present observations assuming anomaly mediation of supersymmetry breaking. As a result, we find that the relic density of the winos is consistent with the observed dark matter density in a wide range of the wino mass, , albeit for a low reheating temperature . [Copyright &y& Elsevier]

Abstract: The results of a search for squarks and gluinos using data from collisions recorded at a center-of-mass energy of 1.96 TeV by the DØ detector at the Fermilab Tevatron Collider are reported. The topologies analyzed consist of acoplanar-jet and multijet events with large missing transverse energy. No evidence for the production of squarks or gluinos was found in a data sample of 310 pb−1. Lower limits of 325 and 241 GeV were derived at the 95% C.L. on the squark and gluino masses, respectively, within the framework of minimal supergravity with , , and . [Copyright &y& Elsevier]

Abstract: In this Letter, we study the half-supersymmetric time-dependent configurations in M-theory and their matrix models. We find a large class of 11D supergravity solutions, which keeps sixteen supersymmetries. Furthermore, we investigate the isometries of these configurations and show that in general these configurations have no supernumerary supersymmetry. And also we define the matrix models in these backgrounds following discrete light-cone quantization (DLCQ) prescription. [Copyright &y& Elsevier]

Abstract: It is known that, for zero fermionic sector, , the bosonic equations of Cremmer–Julia–Scherk eleven-dimensional supergravity can be collected in a compact expression, , which is a condition on the curvature of the generalized connection w. In this Letter we show that the equation , where is the covariant derivative for the generalized connection w, collects all the bosonic equations of supergravity when the gravitino is nonvanishing, . [Copyright &y& Elsevier]

We explicitly construct a solution of eight-dimensional gauged supergravity representing D6-branes wrapped on six-cycles inside Calabi–Yau fourfolds. The solution preserves two supercharges and asymptotically is a cone with the coset space SU(2)4/U(1)3 as its base. It is shown to correspond to an M-theory compactification on a Calabi–Yau manifold with SU(5) holonomy and we discuss in detail its geometrical and topological features. We also construct a family of related higher-dimensional metrics having SU(n+1) holonomy, which of course have no brane interpretation. [Copyright &y& Elsevier]

Abstract: We attempt to reformulate eleven dimensional supergravity in terms of an object that unifies the three-form and the metric and makes the M-theory duality group manifest. This short Letter deals with the case of where the U-duality group acts in five spatial dimensions. [Copyright &y& Elsevier]