Harmonic polylogarithms for massive Bhabha scattering

One- and two-dimensional harmonic polylogarithms, HPLs and GPLs, appear in calculations of multi-loop integrals. We discuss them in the context of analytical solutions for two-loop master integrals in the case of massive Bhabha scattering in QED. For the GPLs we discuss analytical representations, conformal transformations, and also their transformations corresponding to relations between master integrals in the s- and t-channel.Comment: 6 pages, latex, uses espcrc2.sty, contrib. to Proc. of X. Int. Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT), May 22 - 27, 2005, DESY, Zeuthen, Germany, to appear in NI

Spin Dependence of Deep Inelastic Diffraction

Using a perturbative model for diffractive interactions, we derive an expression for the polarized diffractive structure function $g_1^D$ in the high energy limit. This structure function is given by the interference of diffractive amplitudes with polarized and unpolarized exchanges. For the polarized exchange we consider both two-gluon and quark-antiquark amplitudes. The polarized diffractive amplitude receives sizable contributions from non-strongly ordered regions in phase space, resulting in a double logarithmic enhancement at small $x$. The resummation of these double logarithmic terms is outlined. We also discuss the transition from our perturbative expression to the nonperturbative region. A first numerical estimate indicates that the perturbative contribution to the spin asymmetry is substantially larger than the nonperturbative one.Comment: 16 pages, LaTeX, 1 figure include

Transverse parton distribution functions at next-to-next-to-leading order: the quark-to-quark case

We present a calculation of the perturbative quark-to-quark transverse parton distribution function at next-to-next-to-leading order based on a gauge invariant operator definition. We demonstrate for the first time that such a definition works beyond the first non-trivial order. We extract from our calculation the coefficient functions relevant for a next-to-next-to-next-to-leading logarithmic $Q_T$ resummation in a large class of processes at hadron colliders.Comment: 4 pages, 1 figure, revised version, accepted for publication in PR

Letter from US Representative B. J. Gehrmann to Representative Burdick Regarding Indian Department, October 9, 1935

This letter, dated October 9, 1935, from United States (US) Representative from Wisconsin B. J. Gehrmann to US Representative Usher Burdick states that Gehrmann has received requests for copies of a bill that Burdick introduced regarding the reorganization or elimination of the Indian Department. The document has a handwritten note at the bottom signed by Burdick that reads Margaret: send him some Bills and write him I intend to push the Bill with what force I can muster.https://commons.und.edu/burdick-papers/1120/thumbnail.jp

Double virtual corrections for gluon scattering at NNLO

We use the antenna subtraction method to isolate the double virtual infrared singularities present in gluonic scattering amplitudes at next-to-next-to-leading order. In previous papers, we derived the subtraction terms that rendered (a) the double real radiation tree-level process finite in the single and double unresolved regions of phase space and (b) the mixed single real radiation one-loop process both finite and well behaved in the unresolved regions of phase space. Here, we show how to construct the double virtual subtraction term using antenna functions with both initial- and final-state partons which remove the explicit infrared poles present in the two-loop amplitude. As an explicit example, we write down the subtraction term for the four-gluon two-loop process. The infrared poles are explicitly and locally cancelled in all regions of phase space leaving a finite remainder that can be safely evaluated numerically in four-dimensions

Antenna subtraction with massive fermions at NNLO: Double real initial-final configurations

We derive the integrated forms of specific initial-final tree-level four-parton antenna functions involving a massless initial-state parton and a massive final-state fermion as hard radiators. These antennae are needed in the subtraction terms required to evaluate the double real corrections to $t\bar{t}$ hadronic production at the NNLO level stemming from the partonic processes $q\bar{q}\to t\bar{t}q'\bar{q}'$ and $gg\to t\bar{t}q\bar{q}$.Comment: 24 pages, 1 figure, 1 Mathematica file attache

The Harada Method – A Method for Employee Development during Production Ramp Up

Caused by shorter product life cycles and higher product variety the importance of production ramp ups is increasing. Even though companies are aware of that fact, up to 40% of the ramp up projects still miss technical and economical requirements. The success of a ramp up depends on the planning of human factors, organizational aspects and technological solutions. Since only partly considered in scientific literature, this paper lays its focus on the human factor during production ramp up. There are only incoherent methods which address the problems in this area. A systematic and holistic method to improve the capabilities of the employees during ramp up is missing. The Harada Method is a relatively young approach for developing highly-skilled workers. It consists of different worksheets which help employees to set guidelines and reach overall objectives. This approach is going to be transferred into a tool for ramp up management

Precise predictions for dijet production at the LHC

We present the calculation of dijet production, doubly differential in dijet mass m j j and rapidity difference | y ∗ | , at leading color in all partonic channels at next-to-next-to-leading order (NNLO) in perturbative QCD. We consider the long-standing problems associated with scale choice for dijet production at next-to-leading order (NLO) and investigate the impact of including the NNLO contribution. We find that the NNLO theory provides reliable predictions, even when using scale choices that display pathological behavior at NLO. We choose the dijet invariant mass as the theoretical scale on the grounds of perturbative convergence and residual scale variation and compare the predictions to the ATLAS 7 TeV 4.5     fb − 1 data