Antitrust Challenge to Non-Profit Certification Organizations: Conflicts of Interest and a Practical Rule of Reason Approach to Certification Programs As Industry-Wide Builders of Competition and Efficiency

The paramount antitrust challenge for nonprofit product certification programs is to demonstrate aggressively that such programs strengthen the competitive market system on an industry-wide basis. This affirmative challenge is, however, limited by another urgent antitrust challenge still closer to the courtroom door. This challenge, requiring advance organizational and litigation planning, is to avoid or defeat a possible plaintiff\u27s claim of antitrust abuses by a certification organization whose decision-making participants may be caught in alleged conflicts of interest. These two challenges must be met for certification programs to survive and progress. The only way successfully to meet these antitrust challenges is to make product performance certification programs synonymous with industry-wide competition and productivity and with systems of safeguards against conflicts of interest. Further, this must be proved to the judge and jury. This Commentary will discuss two critical questions that flow from an analytical approach to these two challenges: First, whether a coherent basis exists for viewing nonprofit certification programs as structural elements in the marketplace hierarchy that advance urgent antitrust goals, including increased competition and productivity; and second, whether a distinct duty to safeguard certification organizations against conflicts of interest would, if met, demonstrate that a certification organization under antitrust scrutiny in court should be found to be without conspiratorial intent

spinney: A Form Library for Helicity Spinors

In this work, the library spinney is presented, which provides an implementation of helicity spinors and related algorithms for the symbolical manipulation program Form. The package is well suited for symbolic amplitude calculations both in traditional, Feynman diagram based approaches and unitarity-based techniques.Comment: 39 pages, 3 figure

On Tree Amplitudes in Gauge Theory and Gravity

The BCFW recursion relations provide a powerful way to compute tree amplitudes in gauge theories and gravity, but only hold if some amplitudes vanish when two of the momenta are taken to infinity in a particular complex direction. This is a very surprising property, since individual Feynman diagrams all diverge at infinite momentum. In this paper we give a simple physical understanding of amplitudes in this limit, which corresponds to a hard particle with (complex) light-like momentum moving in a soft background, and can be conveniently studied using the background field method exploiting background light-cone gauge. An important role is played by enhanced spin symmetries at infinite momentum--a single copy of a "Lorentz" group for gauge theory and two copies for gravity--which together with Ward identities give a systematic expansion for amplitudes at large momentum. We use this to study tree amplitudes in a wide variety of theories, and in particular demonstrate that certain pure gauge and gravity amplitudes do vanish at infinity. Thus the BCFW recursion relations can be used to compute completely general gluon and graviton tree amplitudes in any number of dimensions. We briefly comment on the implications of these results for computing massive 4D amplitudes by KK reduction, as well understanding the unexpected cancelations that have recently been found in loop-level gravity amplitudes.Comment: 22 pages, 3 figure

NLO Higgs boson production plus one and two jets using the POWHEG BOX, MadGraph4 and MCFM

We present a next-to-leading order calculation of Higgs boson production plus one and two jets via gluon fusion interfaced to shower Monte Carlo programs, implemented according to the POWHEG method. For this implementation we have used a new interface of the POWHEG BOX with MadGraph4, that generates the codes for generic Born and real processes automatically. The virtual corrections have been taken from the MCFM code. We carry out a simple phenomenological study of our generators, comparing them among each other and with fixed next-to-leading order results.Comment: 27 pages, 21 figure

Multigluon tree amplitudes with a pair of massive fermions

We consider the calculation of n-point multigluon tree amplitudes with a pair of massive fermions in QCD. We give the explicit transformation rules of this kind of massive fermion-pair amplitudes with respect to different reference momenta and check the correctness of them by SUSY Ward identities. Using these rules and onshell BCFW recursion relation, we calculate the analytic results of several n-point multigluon amplitudes.Comment: 15page

Quasisymmetry and rectifiability of quasispheres

We obtain Dini conditions with "exponent 2" that guarantee that an asymptotically conformal quasisphere is rectifiable. In particular, we show that for any e>0 integrability of (esssup_{1-t < |x| < 1+t} K_f(x)-1)^{2-e} dt/t implies that the image of the unit sphere under a global quasiconformal homeomorphism f is rectifiable. We also establish estimates for the weak quasisymmetry constant of a global K-quasiconformal map in neighborhoods with maximal dilatation close to 1.Comment: 19 pages, 3 figures (version 3: minor changes and typos fixed

Scattering AMplitudes from Unitarity-based Reduction Algorithm at the Integrand-level

SAMURAI is a tool for the automated numerical evaluation of one-loop corrections to any scattering amplitudes within the dimensional-regularization scheme. It is based on the decomposition of the integrand according to the OPP-approach, extended to accommodate an implementation of the generalized d-dimensional unitarity-cuts technique, and uses a polynomial interpolation exploiting the Discrete Fourier Transform. SAMURAI can process integrands written either as numerator of Feynman diagrams or as product of tree-level amplitudes. We discuss some applications, among which the 6- and 8-photon scattering in QED, and the 6-quark scattering in QCD. SAMURAI has been implemented as a Fortran90 library, publicly available, and it could be a useful module for the systematic evaluation of the virtual corrections oriented towards automating next-to-leading order calculations relevant for the LHC phenomenology.Comment: 35 pages, 7 figure

Platform work, exploitation, and migrant worker resistance: evidence from Berlin and London

For migrant workers who do not have access to other means of income, the platform economy offers a viable yet exploitative alternative to the conventional labour market. Migrant workers are used as a source of cheap labour by platforms – and yet, they are not disempowered. They are at the heart of a growing platform worker movement. Across different international contexts, migrants have played a key role in leading strikes and other forms of collective action. This article traces the struggles of migrant platform workers in Berlin and London to explore how working conditions, work experiences, and strategies for collective action are shaped at the intersection of multiple precarities along lines of employment and migration status. Combining data collected through research by the Fairwork project with participant observation and ethnography, the article argues that migrant workers are more than an exploitable resource: they are harbingers of change

An Integrand Reconstruction Method for Three-Loop Amplitudes

We consider the maximal cut of a three-loop four point function with massless kinematics. By applying Groebner bases and primary decomposition we develop a method which extracts all ten propagator master integral coefficients for an arbitrary triple-box configuration via generalized unitarity cuts. As an example we present analytic results for the three loop triple-box contribution to gluon-gluon scattering in Yang-Mills with adjoint fermions and scalars in terms of three master integrals.Comment: 15 pages, 1 figur