Higher Dimensional Effective Operators for Direct Dark Matter Detection

We discuss higher dimensional effective operators describing interactions between fermionic dark matter and Standard Model particles. They are typically suppressed compared to the leading order effective operators, which can explain why no conclusive direct dark matter detection has been made so far. The ultraviolet completions of the effective operators, which we systematically study, require new particles. These particles can potentially have masses at the TeV scale and can therefore be phenomenologically interesting for LHC physics. We demonstrate that the lowest order options require Higgs-portal interactions generated by dimension six operators. We list all possible tree-level completions with extra fermions and scalars, and we discuss the LHC phenomenology of a specific example with extra heavy fermion doublets.Comment: 27 pages, 11 figures, 3 table

The conceptualisation and measurement of pedagogical content knowledge and content knowledge in the COACTIV study and their impact on student learning

An ongoing question is the extent to which teachers' professional knowledge has an impacton their teaching and, in particular, on their students' achievement. The COACTIV1 studysurveyed and tested the mathematics teachers of the classes sampled for PISA 2003/04 inGermany. The study’s key components were newly developed tests of teachers’ pedagogicalcontent knowledge and content knowledge. This article gives a report of theconceptualisation and operationalisation of both domains of knowledge and describes theconstruction of the COACTIV tests. Findings from the tests show that there are differenceswith respect to both knowledge domains regarding teachers’ school types, but thatpedagogical content knowledge and content knowledge astoundingly both do not depend onteaching experience. Furthermore we show that the two domains of knowledge correlatepositively with constructivist teachers’ subjective beliefs, on the one hand, and with somecrucial aspects of their instruction, on the other hand. Finally, we show that pedagogicalcontent knowledge – but not pure content knowledge per se – significantly contributes tostudents’ learning gains

A constrained supersymmetric left-right model

We present a supersymmetric left-right model which predicts gauge coupling unification close to the string scale and extra vector bosons at the TeV scale. The subtleties in constructing a model which is in agreement with the measured quark masses and mixing for such a low left-right breaking scale are discussed. It is shown that in the constrained version of this model radiative breaking of the gauge symmetries is possible and a SM-like Higgs is obtained. Additional CP-even scalars of a similar mass or even much lighter are possible. The expected mass hierarchies for the supersymmetric states differ clearly from those of the constrained MSSM. In particular, the lightest down-type squark, which is a mixture of the sbottom and extra vector-like states, is always lighter than the stop. We also comment on the model's capability to explain current anomalies observed at the LHC.Comment: 21 pages, 5 figures; v2: references added, matches published versio

Dark matter scenarios in a constrained model with Dirac gauginos

We perform the first analysis of Dark Matter scenarios in a constrained model with Dirac Gauginos. The model under investigation is the Constrained Minimal Dirac Gaugino Supersymmetric Standard model (CMDGSSM) where the Majorana mass terms of gauginos vanish. However, $R$-symmetry is broken in the Higgs sector by an explicit and/or effective $B_\mu$-term. This causes a mass splitting between Dirac states in the fermion sector and the neutralinos, which provide the dark matter candidate, become pseudo-Dirac states. We discuss two scenarios: the universal case with all scalar masses unified at the GUT scale, and the case with non-universal Higgs soft-terms. We identify different regions in the parameter space which fullfil all constraints from the dark matter abundance, the limits from SUSY and direct dark matter searches and the Higgs mass. Most of these points can be tested with the next generation of direct dark matter detection experiments.Comment: 28 pages, 11 figures; v2: minor changes, title modified; matches published versio

Neutrino mass from higher than d=5 effective operators in SUSY, and its test at the LHC

We discuss neutrino masses from higher than d=5 effective operators in a supersymmetric framework, where we explicitly demonstrate which operators could be the leading contribution to neutrino mass in the MSSM and NMSSM. As an example, we focus on the d=7 operator L L H_u H_u H_d H_u, for which we systematically derive all tree-level decompositions. We argue that many of these lead to a linear or inverse see-saw scenario with two extra neutral fermions, where the lepton number violating term is naturally suppressed by a heavy mass scale when the extra mediators are integrated out. We choose one example, for which we discuss possible implementations of the neutrino flavor structure. In addition, we show that the heavy mediators, in this case SU(2) doublet fermions, may indeed be observable at the LHC, since they can be produced by Drell-Yan processes and lead to displaced vertices when they decay. However, the direct observation of lepton number violating processes is on the edge at LHC.Comment: 24 pages, 5 figures, 6 table