3,478 research outputs found
Constraining Light Colored Particles with Event Shapes
Using recently developed techniques for computing event shapes with
Soft-Collinear Effective Theory, LEP event shape data is used to derive strong
model-independent bounds on new colored particles. In the effective field
theory computation, colored particles contribute in loops not only to the
running of alpha_s but also to the running of hard, jet and soft functions.
Moreover, the differential distribution in the effective theory explicitly
probes many energy scales, so event shapes have strong sensitivity to new
particle thresholds. Using thrust data from ALEPH and OPAL, colored adjoint
fermions (such as a gluino) below 51.0 GeV are ruled out to 95% confidence
level. This is nearly an order-of-magnitude improvement over the previous
model-independent bound of 6.3 GeV.Comment: 4 pages, 2 figure
Ecumenical modal logic
The discussion about how to put together Gentzen's systems for classical and
intuitionistic logic in a single unified system is back in fashion. Indeed,
recently Prawitz and others have been discussing the so called Ecumenical
Systems, where connectives from these logics can co-exist in peace. In Prawitz'
system, the classical logician and the intuitionistic logician would share the
universal quantifier, conjunction, negation, and the constant for the absurd,
but they would each have their own existential quantifier, disjunction, and
implication, with different meanings. Prawitz' main idea is that these
different meanings are given by a semantical framework that can be accepted by
both parties. In a recent work, Ecumenical sequent calculi and a nested system
were presented, and some very interesting proof theoretical properties of the
systems were established. In this work we extend Prawitz' Ecumenical idea to
alethic K-modalities
Probing Trilinear Gauge Boson Interactions via Single Electroweak Gauge Boson Production at the LHC
We analyze the potential of the CERN Large Hadron Collider (LHC) to study
anomalous trilinear vector-boson interactions W^+ W^- \gamma and W^+ W^- Z
through the single production of electroweak gauge bosons via the weak boson
fusion processes q q -> q q W (-> \ell^\pm \nu) and q q -> q q Z(-> \ell^+
\ell^-) with \ell = e or \mu. After a careful study of the standard model
backgrounds, we show that the single production of electroweak bosons at the
LHC can provide stringent tests on deviations of these vertices from the
standard model prediction. In particular, we show that single gauge boson
production exhibits a sensitivity to the couplings \Delta \kappa_{Z,\gamma}
similar to that attainable from the analysis of electroweak boson pair
production.Comment: 20 pages, 6 figure
Virtual effects of light gauginos and higgsinos: a precision electroweak analysis of split supersymmetry
We compute corrections to precision electroweak observables in supersymmetry
in the limit that scalar superpartners are very massive and decoupled. This
leaves charginos and neutralinos and a Standard Model-like Higgs boson as the
only states with unknown mass substantially affecting the analysis. We give
complete formulas for the chargino and neutralino contributions, derive simple
analytic results for the pure gaugino and higgsino cases, and study the general
case. We find that in all circumstances, the precision electroweak fit improves
when the charginos and neutralinos are near the current direct limits. Larger
higgsino and gaugino masses worsen the fit as the theory predictions
asymptotically approach those of the Standard Model. Since the Standard Model
is considered by most to be an adequate fit to the precision electroweak data,
an important corollary to our analysis is that all regions of parameter space
allowed by direct collider constraints are also allowed by precision
electroweak constraints in split supersymmetry.Comment: 22 pages, 5 figures, v2: typos fixed and note adde
Completeness for a First-order Abstract Separation Logic
Existing work on theorem proving for the assertion language of separation
logic (SL) either focuses on abstract semantics which are not readily available
in most applications of program verification, or on concrete models for which
completeness is not possible. An important element in concrete SL is the
points-to predicate which denotes a singleton heap. SL with the points-to
predicate has been shown to be non-recursively enumerable. In this paper, we
develop a first-order SL, called FOASL, with an abstracted version of the
points-to predicate. We prove that FOASL is sound and complete with respect to
an abstract semantics, of which the standard SL semantics is an instance. We
also show that some reasoning principles involving the points-to predicate can
be approximated as FOASL theories, thus allowing our logic to be used for
reasoning about concrete program verification problems. We give some example
theories that are sound with respect to different variants of separation logics
from the literature, including those that are incompatible with Reynolds's
semantics. In the experiment we demonstrate our FOASL based theorem prover
which is able to handle a large fragment of separation logic with heap
semantics as well as non-standard semantics.Comment: This is an extended version of the APLAS 2016 paper with the same
titl
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This paper discusses research on Friedrich Nietzsche's affirmation of tragic morality
General-elimination stability
General-elimination harmony articulates Gentzen's idea that the elimination-rules are justified if they infer from an assertion no more than can already be inferred from the grounds for making it. Dummett described the rules as not only harmonious but stable if the E-rules allow one to infer no more and no less than the I-rules justify. Pfenning and Davies call the rules locally complete if the E-rules are strong enough to allow one to infer the original judgement. A method is given of generating harmonious general-elimination rules from a collection of I-rules. We show that the general-elimination rules satisfy Pfenning and Davies' test for local completeness, but question whether that is enough to show that they are stable. Alternative conditions for stability are considered, including equivalence between the introduction- and elimination-meanings of a connective, and recovery of the grounds for assertion, finally generalizing the notion of local completeness to capture Dummett's notion of stability satisfactorily. We show that the general-elimination rules meet the last of these conditions, and so are indeed not only harmonious but also stable.Publisher PDFPeer reviewe
The deal.II Library, Version 8.3
deal.II version 8.3 was released August 1, 2015. This paper provides an overview of the new features of this release and serves as a citable reference for the deal.II software library version 8.3. deal.II is an object-oriented finite element library used around the world in the development of finite element solvers. It is available for free under the GNU Lesser General Public License (LGPL) from the deal.II homepage at http://www.dealii.org/
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