1,154 research outputs found
Precision predictions for direct gaugino and slepton production at the LHC
The search for electroweak superpartners has recently moved to the centre of
interest at the LHC. We provide the currently most precise theoretical
predictions for these particles, use them to assess the precision of parton
shower simulations, and reanalyse public experimental results assuming more
general decompositions of gauginos and sleptons.Comment: 5 pages, 2 tables, 5 figures, proceedings of ICHEP 201
Graded Differential Geometry of Graded Matrix Algebras
We study the graded derivation-based noncommutative differential geometry of
the -graded algebra of complex -matrices
with the ``usual block matrix grading'' (for ). Beside the
(infinite-dimensional) algebra of graded forms the graded Cartan calculus,
graded symplectic structure, graded vector bundles, graded connections and
curvature are introduced and investigated. In particular we prove the
universality of the graded derivation-based first-order differential calculus
and show, that is a ``noncommutative graded manifold'' in a
stricter sense: There is a natural body map and the cohomologies of and its body coincide (as in the case of ordinary graded manifolds).Comment: 21 pages, LATE
Chern-Simons action for inhomogeneous Virasoro group as an extension of three dimensional flat gravity
We initiate the study of a Chern-Simons action associated to the semi-direct
sum of the Virasoro algebra with its coadjoint representation. This model
extends the standard Chern-Simons formulation of three dimensional flat gravity
and is similar to the higher-spin extension of three dimensional anti-de Sitter
or flat gravity. The extension can also be constructed for the exotic but not
for the cosmological constant deformation of flat gravity.Comment: 15 pages. Version to appear in J. of Math. Phy
Monojet searches for momentum-dependent dark matter interactions
We consider minimal dark matter scenarios featuring momentum-dependent couplings of the dark sector to the Standard Model. We derive constraints from existing LHC searches in the monojet channel, estimate the future LHC sensitivity for an integrated luminosity of 300 fb−1, and compare with models exhibiting conventional momentum-independent interactions with the dark sector. In addition to being well motivated by (composite) pseudo-Goldstone dark matter scenarios, momentum-dependent couplings are interesting as they weaken direct detection constraints. For a specific dark matter mass, the LHC turns out to be sensitive to smaller signal cross-sections in the momentum-dependent case, by virtue of the harder jet transverse-momentum distribution
Odd Chern-Simons Theory, Lie Algebra Cohomology and Characteristic Classes
We investigate the generic 3D topological field theory within AKSZ-BV
framework. We use the Batalin-Vilkovisky (BV) formalism to construct explicitly
cocycles of the Lie algebra of formal Hamiltonian vector fields and we argue
that the perturbative partition function gives rise to secondary characteristic
classes. We investigate a toy model which is an odd analogue of Chern-Simons
theory, and we give some explicit computation of two point functions and show
that its perturbation theory is identical to the Chern-Simons theory. We give
concrete example of the homomorphism taking Lie algebra cocycles to
Q-characteristic classes, and we reinterpreted the Rozansky-Witten model in
this light.Comment: 52 page
Cohomology of Lie superalgebras and of their generalizations
The cohomology groups of Lie superalgebras and, more generally, of color Lie
algebras, are introduced and investigated. The main emphasis is on the case
where the module of coefficients is non-trivial. Two general propositions are
proved, which help to calculate the cohomology groups. Several examples are
included to show the peculiarities of the super case. For L = sl(1|2), the
cohomology groups H^1(L,V) and H^2(L,V), with V a finite-dimensional simple
graded L-module, are determined, and the result is used to show that
H^2(L,U(L)) (with U(L) the enveloping algebra of L) is trivial. This implies
that the superalgebra U(L) does not admit of any non-trivial formal
deformations (in the sense of Gerstenhaber). Garland's theory of universal
central extensions of Lie algebras is generalized to the case of color Lie
algebras.Comment: 50 pages, Latex, no figures. In the revised version the proof of
Lemma 5.1 is greatly simplified, some references are added, and a pertinent
result on sl(m|1) is announced. To appear in the Journal of Mathematical
Physic
An Analysis of the Representations of the Mapping Class Group of a Multi-Geon Three-Manifold
It is well known that the inequivalent unitary irreducible representations
(UIR's) of the mapping class group of a 3-manifold give rise to ``theta
sectors'' in theories of quantum gravity with fixed spatial topology. In this
paper, we study several families of UIR's of and attempt to understand the
physical implications of the resulting quantum sectors. The mapping class group
of a three-manifold which is the connected sum of with a finite number
of identical irreducible primes is a semi-direct product group. Following
Mackey's theory of induced representations, we provide an analysis of the
structure of the general finite dimensional UIR of such a group. In the picture
of quantized primes as particles (topological geons), this general
group-theoretic analysis enables one to draw several interesting qualitative
conclusions about the geons' behavior in different quantum sectors, without
requiring an explicit knowledge of the UIR's corresponding to the individual
primes.Comment: 52 pages, harvmac, 2 postscript figures, epsf required. Added an
appendix proving the semi-direct product structure of the MCG, corrected an
error in the characterization of the slide subgroup, reworded extensively.
All our analysis and conclusions remain as befor
Cyclic Statistics In Three Dimensions
While 2-dimensional quantum systems are known to exhibit non-permutation,
braid group statistics, it is widely expected that quantum statistics in
3-dimensions is solely determined by representations of the permutation group.
This expectation is false for certain 3-dimensional systems, as was shown by
the authors of ref. [1,2,3]. In this work we demonstrate the existence of
``cyclic'', or , {\it non-permutation group} statistics for a system of n
> 2 identical, unknotted rings embedded in . We make crucial use of a
theorem due to Goldsmith in conjunction with the so called Fuchs-Rabinovitch
relations for the automorphisms of the free product group on n elements.Comment: 13 pages, 1 figure, LaTex, minor page reformattin
Discovering clinical phronesis.
Phronesis is often described as a 'practical wisdom' adapted to the matters of everyday human life. Phronesis enables one to judge what is at stake in a situation and what means are required to bring about a good outcome. In medicine, phronesis tends to be called upon to deal with ethical issues and to offer a critique of clinical practice as a straightforward instrumental application of scientific knowledge. There is, however, a paucity of empirical studies of phronesis, including in medicine. Using a hermeneutic and phenomenological approach, this inquiry explores how phronesis is manifest in the stories of clinical practice of eleven exemplary physicians. The findings highlight five overarching themes: ethos (or character) of the physician, clinical habitus revealed in physician know-how, encountering the patient with attentiveness, modes of reasoning amidst complexity, and embodied perceptions (such as intuitions or gut feeling). The findings open a discussion about the contingent nature of clinical situations, a hermeneutic mode of clinical thinking, tacit dimensions of being and doing in clinical practice, the centrality of caring relations with patients, and the elusive quality of some aspects of practice. This study deepens understandings of the nature of phronesis within clinical settings and proposes 'Clinical phronesis' as a descriptor for its appearance and role in the daily practice of (exemplary) physicians
An empirical and philosophical exploration of clinical practice.
Previous empirical work among physicians has led us to propose that clinical practice is experienced by clinicians as an engagement-in-the-clinical-situation. In this study, we pursue our exploration of clinical practice 'on its own terms' by turning to the experience of patients.
Phenomenological analysis of in-depth individual interviews with 8 patients.
We describe the patient experience as a set of three motifs: the shock on the realization of the illness, the chaos of the health care environment, and the anchor point provided by an engaged physician. We draw on Heidegger's notion of solicitude to show that patients are actively ascertaining the physician's engagement in their care.
These findings lead us to question the classical "dual discourse" of medicine that offers a dichotomous account of clinical practice as the addition of care to cure, art to science, humanism to technique, and person to medical case. We found no such distinctions in our empirical investigation of clinical practice. Rather, in our synthesis, practice appears as a unitary experience. The physician's solicitude for the patient entrains engagement in the clinical situation. Moreover, the solicitous, engaged physician constitutes an anchor point for the patient
- …