We investigate a new class of dark matter: superweakly-interacting massive particles (superWIMPs). As with conventional WIMPs, superWIMPs appear in well-motivated particle theories with naturally the correct relic density. In contrast to WIMPs, however, superWIMPs are impossible to detect in all conventional dark matter searches. We consider the concrete examples of gravitino and graviton cold dark matter in models with supersymmetry and universal extra dimensions, respectively, and show that superWIMP dark matter satisfies stringent constraints from Big Bang nucleosynthesis and the cosmic microwave background.PACS numbers: 95.35.+d, 4.65.+e, 11.10.Kk, 12.60.Jv There is ample evidence that luminous matter makes up only a small fraction of all matter in the universe. Results from the Wilkinson Microwave Anisotropy Probe, combined with other data, constrain the non-baryonic dark matter density to Ω DM = 0.23 ± 0.04 [1], far in excess of the luminous matter density. We therefore live in interesting times: while the amount of dark matter is becoming precisely known, its identity remains a mystery.WIMPs, weakly-interacting massive particles with weak-scale masses, are particularly attractive dark matter candidates. WIMPs have several virtues. First, their appearance in particle physics theories is independently motivated by the problem of electroweak symmetry breaking. Second, given standard cosmological assumptions, their thermal relic abundance is naturally that required for dark matter. Third, the requirement that WIMPs annihilate efficiently enough to give the desired relic density generically implies that WIMP-matter interactions are strong enough for dark matter to be discovered in current or near future experiments.Here we consider a new class of non-baryonic cold dark matter: superweakly-interacting massive particles (superWIMPs or SWIMPs). As with WIMPs, superWIMPs appear in well-motivated theoretical frameworks, such as supersymmetry and extra dimensions, and their (nonthermal) relic density is also naturally in the desired range. In contrast to conventional WIMPs, however, they interact superweakly and so evade all direct and indirect dark matter detection experiments proposed to date.For concreteness, we consider two specific superWIMPs: gravitinos in supersymmetric theories, and Kaluza-Klein (KK) gravitons in theories with extra dimensions. Gravitino and graviton superWIMPs share many features, and we investigate them in parallel.For gravitino superWIMPs, we consider supergravity, where the gravitinoG and all standard model (SM) superpartners have weak-scale masses. Assuming R-parity conservation, the lightest supersymmetric particle (LSP) is stable. In supergravity, the LSP is usually assumed to be a SM superpartner. Neutralino LSPs are excellent WIMP candidates, giving the desired thermal relic density for masses of 50 GeV to 2 TeV, depending on Higgsino content. In contrast, here we assume aG LSP. The gravitinos considered here couple gravitationally and form cold dark matter, in contrast to the ca...

We show that colliders can impose strong constraints on models of dark matter, in particular, when the dark matter is light. We analyze models where the dark matter is a fermion or scalar interacting with quarks and/or gluons through an effective theory containing higher dimensional operators which represent heavier states that have been integrated out of the effective field theory. We determine bounds from existing Tevatron searches for monojets as well as expected LHC reaches for a discovery. We find that colliders can provide information which is complementary or in some cases even superior to experiments searching for direct detection of dark matter through its scattering with nuclei. In particular, both the Tevatron and the LHC can outperform spin-dependent searches by an order of magnitude or better over much of the parameter space, and if the dark matter couples mainly to gluons, the LHC can place bounds superior to any spin-independent search.

We explore model-independent collider constraints on light Majorana dark matter particles. We find that colliders provide a complementary probe of WIMPs to direct detection, and give the strongest current constraints on light DM particles. Collider experiments can access interactions not probed by direct detection searches, and outperform direct detection experiments by about an order of magnitude for certain operators in a large part of parameter space. For operators which are suppresssed at low momentum transfer, collider searches have already placed constraints on such operators limiting their use as an explanation for DAMA. * *

In models of universal extra dimensions, gravity and all standard model fields propagate in the extra dimensions. Previous studies of such models have concentrated on the Kaluza-Klein (KK) partners of standard model particles. Here we determine the properties of the KK gravitons and explore their cosmological implications. We find the lifetimes of decays to KK gravitons, of relevance for the viability of KK gravitons as dark matter. We then discuss the primordial production of KK gravitons after reheating. The existence of a tower of KK graviton states makes such production extremely efficient: for reheat temperature T RH and d extra dimensions, the energy density stored in gravitons scales as T 2+3d/2 RH . Overclosure and Big Bang nucleosynthesis therefore stringently constrain T RH in all universal extra dimension scenarios. At the same time, there is a window of reheat temperatures low enough to avoid these constraints and high enough to generate the desired thermal relic density for KK WIMP and superWIMP dark matter.

The adS p+2 × S d−p−2 geometry of the near horizon branes is promoted to a supergeometry: the solution of the supergravity constraints for the vielbein, connection and form superfields are found. This supergeometry can be used for the construction of new superconformal theories. We also discuss the Green-Schwarz action for a type IIB string on adS 5 × S 5 . a

We derive limits on the interactions of dark matter with quarks from ATLAS null searches for jets + missing energy based on ∼ 1 fb −1 of integrated luminosity, using a model-insensitive effective theory framework. We find that the new limits from the LHC significantly extend limits previously derived from CDF data at the Tevatron. Translated into the parameter space of direct searches, these limits are particularly effective for ∼ GeV mass WIMPs. Our limits indicate tension with isospin violating models satisfying minimal flavor violation which attempt to reconcile the purported CoGeNT excess with Xenon-100, indicating that either a light mediator or nontrivial flavor structure for the dark sector is necessary for a viable reconciliation of CoGeNT with Xenon.

Cold dark matter may be made of superweakly interacting massive particles, super-WIMP's, that naturally inherit the desired relic density from late decays of metastable WIMP's. Well-motivated examples are weakscale gravitinos in supergravity and Kaluza-Klein gravitons from extra dimensions. These particles are impossible to detect in all dark matter experiments. We find, however, that super-WIMP dark matter may be discovered through cosmological signatures from the early Universe. In particular, super-WIMP dark matter has observable consequences for big bang nucleosynthesis and the cosmic microwave background ͑CMB͒, and may explain the observed underabundance of 7 Li without upsetting the concordance between deuterium and CMB baryometers. We discuss the implications for future probes of CMB blackbody distortions and collider searches for new particles. In the course of this study, we also present a model-independent analysis of entropy production from late-decaying particles in light of Wilkinson microwave anisotropy probe data.

Using M(atrix) Theory, the dualities of toroidally compactified M-theory can be formulated as properties of super Yang Mills theories in various dimensions. We consider the cases of compactification on one, two, three, four and five dimensional tori. The dualities required by string theory lead to conjectures of remarkable symmetries and relations between field theories as well as extremely unusual dynamical properties. By studying the theories in the limit of vanishingly small tori, a wealth of information is obtained about strongly coupled fixed points of super Yang-Mills theory in various dimensions. Perhaps the most striking behavior, as noted by Rozali in this context, is the emergence of an additional dimension of space in the case of a four torus.