The Pitfalls of Dark Crossings

We explore the connection between pair production of dark matter particles at collider experiments and annihilation of dark matter in the early and late universe, with a focus on the correlation between the two time-reversed processes. We consider both a model-independent effective theory framework, where the initial and final states are assumed to not change under time-reversal, and concrete UV-complete models within the framework of supersymmetric extensions to the Standard Model. Even within the effective theory framework (where crossing symmetry is in some sense assumed), we find that the predictions of that symmetry can vary by orders of magnitude depending on the details of the selected effective interaction. Within the supersymmetric models we consider, we find that there is an even wilder variation in the expectations one can derive for collider observables based on cross-symmetric processes such as having a thermal relic or given indirect dark matter detection rates. We also explore additional "pitfalls" where na\"ive crossing symmetry badly fails, including models with very light mediators leading to Sommerfeld enhancements and/or dark matter bound states.Comment: 13 pages, 4 figure

Narratives of power: bringing ideology to the fore of planning analysis

This Special Issue starts from the premise that the concept of ideology holds significant analytical potential for planning but that this potential can only be realised if ideology is brought to the fore of analysis. By naming ideology and rendering it visible, we hope to bring it out from the shadows and into the open to examine its value and what it can tell us about the politics of contemporary planning. The papers in this Special Issue therefore seek to contribute to established academic debates by exploring some of the ways ideology can be deployed as a tool in the analysis of planning problems. This article introduces the Special Issue by exploring the various accounts in the papers of i. what ideology is; ii. what its effects are; iii. where ideology may be identified and iv. what different theories of ideology can tell us about planning. There inevitably remain many un-answered questions, paths not taken and debates left unaddressed. We hope other scholars will be inspired (or provoked) to address these omissions in the future

Tagging Boosted Ws with Wavelets

We present a new technique for distinguishing the hadronic decays of boosted heavy particles from QCD backgrounds based on wavelet transforms. As an initial exploration, we illustrate the technique in the particular case of hadronic $W$ boson decays, comparing it to the ``mass drop'' cut currently used by the LHC experiments. We apply wavelet cuts, which make use of complementary information, and in combination with the mass drop cut results in an improvement of $\sim$7% in discovery reach of hadronic $W$ boson final states over a wide range of transverse momenta.Comment: 14 pages, 5 figure

Constraints on Light Majorana Dark Matter from Colliders

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.Comment: 4 pages, 6 figure

Concentration and Extraction of Phosphorous from Swine Manure Slurries (as Struvite)

Excessive loading of phosphorus (P) onto agricultural lands has been recognized as a threat to surface water quality. Forced precipitation of struvite (MgNH4PO4•6H2O) from animal waste slurries prior to land application can reduce dissolved reactive P levels in manure slurries. It also offers the potential to recover excess phosphorus from manures and move it to cropping areas that require phosphorus fertilizer inputs. Past work indicates that ~90% of the soluble phosphorus can be concentrated into a precipitate following chemical amendment. This study will provide important information regarding the feasibility of phosphorus recovery as a means of balancing swine manure nutrient content with crop needs. Given the expanding regulations regarding phosphorus management, it is important to develop and test phosphorus management strategies. The sustainability of many animal operations in their current locations will depend upon their ability to meet new regulations requiring phosphorus management as well as nitrogen management

A design methodology to reduce the embodied carbon of concrete buildings using thin-shell floors

This paper explores the potential of thin concrete shells as low-carbon alternatives to floor slabs and beams, which typically make up the majority of structural material in multi-storey buildings. A simple and practical system is proposed, featuring pre-cast textile reinforced concrete shells with a network of prestressed steel tension ties. A non-structural fill is included to provide a level top surface. Building on previous experimental and theoretical work, a complete design methodology is presented. This is then used to explore the structural behaviour of the proposed system, refine its design, and evaluate potential carbon savings. Compared to flat slabs of equivalent structural performance, significant embodied carbon reductions (53–58%) are demonstrated across spans of 6–18 m. Self-weight reductions of 43–53% are also achieved, which would save additional material in columns and foundations. The simplicity of the proposed structure, and conservatism of the design methodology, indicate that further savings could be made with future refinements. These results show that considerable embodied carbon reductions are possible through innovative structural design, and that thin-shell floors are a practical means of achieving this.</p

Constraints on Dark Matter from Colliders

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 parameter space, and if the dark matter couples mainly to gluons, the LHC can place bounds superior to any spin independent search.Comment: 23 pages, 16 figure