112,009 research outputs found
Long-lived Colored Scalars at the LHC
We study the collider signatures of a long-lived massive colored scalar
transforming trivially under the weak interaction and decaying within the inner
sections of a detector such as ATLAS or CMS. In our study, we assume that the
colored scalar couples at tree-level to a top quark and a stable fermion,
possibly arising from a dark sector or from supersymmetric extensions of the
Standard Model. After implementing the latest experimental searches for
long-lived colored scalars, we observe a region of parameter space consistent
with a colored electroweak-singlet scalar with mass between GeV
and a lifetime between together, with a nearly degenerate
dark fermion that may be probed at the TeV LHC. We show that a
search strategy using a combination of cuts on missing transverse energy and
impact parameters can exclude regions of parameter space not accessed by prompt
searches. We show that a region of parameter space within our simplified model
may naturally arise from the light-stop window regime of supersymmetric
extensions of the Standard Model, where a light mostly right-handed stop has a
mass slightly larger than the lightest neutralino and decays through a
four-body process
European Citizens' Initiative: Legal Options for Implementation Below the Constitutional Level
The EU has long been criticized for its democratic deficit. Several proposals for overcoming or reducing this deficit have been made. Some of them mention the role of more citizen participation and direct democracy. It was in this spirit that the ECI found its way into the Constitutional Treaty, creating the first tool of transnational participatory/direct democracy. It is aimed to give the Uniom's citizens more influence on EU politics while maintaining the institutional balance - especially the initiative monopoly of the European Commission - of the Union
The European Citizens' Initiative: A First Assessment
Designed in order to enable the effective use of this new instrument and to guarantee equal access
Instantaneous Decentralized Poker
We present efficient protocols for amortized secure multiparty computation
with penalties and secure cash distribution, of which poker is a prime example.
Our protocols have an initial phase where the parties interact with a
cryptocurrency network, that then enables them to interact only among
themselves over the course of playing many poker games in which money changes
hands.
The high efficiency of our protocols is achieved by harnessing the power of
stateful contracts. Compared to the limited expressive power of Bitcoin
scripts, stateful contracts enable richer forms of interaction between standard
secure computation and a cryptocurrency.
We formalize the stateful contract model and the security notions that our
protocols accomplish, and provide proofs using the simulation paradigm.
Moreover, we provide a reference implementation in Ethereum/Solidity for the
stateful contracts that our protocols are based on.
We also adopt our off-chain cash distribution protocols to the special case
of stateful duplex micropayment channels, which are of independent interest. In
comparison to Bitcoin based payment channels, our duplex channel implementation
is more efficient and has additional features
Are Online Business Transactions Executed by Electronic Signatures Legally Binding?
Most of us believe that we make contracts over the Internet all the time. We buy books and computers, arrange for hotels and planes, trade stocks, and apply for mortgages. But as recently as seven months ago that transaction was most likely not legally binding. This uncertainty led many practitioners, businesspeople, and consumers to question the efficacy of contracts executed by electronic signatures. Without a uniform standard, many jurisdictions ruled inconsistently, while other jurisdictions did not consider the issue. This disparate treatment threatened the legitimacy of online agreements and deprived both consumers and businesses of the certainty and predictability expected from well-developed markets. The law\u27s formalities evolved outside of the digital world, and the process of adapting them to it has proven to be more difficult than expected. In June of 2000, Congress attempted to solve this problem with the Electronic Signatures in Global and National Commerce Act (E-Sign)
Canonical Abstract Syntax Trees
This paper presents Gom, a language for describing abstract syntax trees and
generating a Java implementation for those trees. Gom includes features
allowing the user to specify and modify the interface of the data structure.
These features provide in particular the capability to maintain the internal
representation of data in canonical form with respect to a rewrite system. This
explicitly guarantees that the client program only manipulates normal forms for
this rewrite system, a feature which is only implicitly used in many
implementations
An Improvement over the GVW Algorithm for Inhomogeneous Polynomial Systems
The GVW algorithm is a signature-based algorithm for computing Gr\"obner
bases. If the input system is not homogeneous, some J-pairs with higher
signatures but lower degrees are rejected by GVW's Syzygy Criterion, instead,
GVW have to compute some J-pairs with lower signatures but higher degrees.
Consequently, degrees of polynomials appearing during the computations may
unnecessarily grow up higher and the computation become more expensive. In this
paper, a variant of the GVW algorithm, called M-GVW, is proposed and mutant
pairs are introduced to overcome inconveniences brought by inhomogeneous input
polynomials. Some techniques from linear algebra are used to improve the
efficiency. Both GVW and M-GVW have been implemented in C++ and tested by many
examples from boolean polynomial rings. The timings show M-GVW usually performs
much better than the original GVW algorithm when mutant pairs are found.
Besides, M-GVW is also compared with intrinsic Gr\"obner bases functions on
Maple, Singular and Magma. Due to the efficient routines from the M4RI library,
the experimental results show that M-GVW is very efficient
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