Structure Functions are not Parton Probabilities

We explain why contrary to common belief, the deep inelastic scattering structure functions are not related to parton probabilities in the target.Comment: 4 pages. Invited talk presented during the `International Light-Cone Workshop', Trento, ECT, September 3-11, 2001. Updated Report-Number

Containing the Not-Invented-Here Syndrome in external knowledge absorption and open innovation: The role of indirect countermeasures

This paper builds new theory and provides supporting evidence to contain the Not-Invented-Here Syndrome (NIHS) – a persistent decision-making error arising from an attitude-based bias against external knowledge. Conceptually, we draw on the 4i framework of organizational learning to develop a novel process perspective on NIHS. This allows us not only to unpack how and where NIHS impedes organizational learning, but also to identify the key requirements for effective NIHS countermeasures. Importantly, countermeasures fall into two categories: those that seek to change the negative attitude directly (direct NIHS countermeasures) and those that seek to attenuate the behavioral impact of negative attitudes without addressing the attitudes as such (indirect NIHS countermeasures). While the evidence base on direct NIHS countermeasures has grown over the last decade, indirect NIHS countermeasures have received little research attention. To address this gap, we adopt a mixed methods research design composed of two complementary empirical studies – the first qualitative and the second quantitative. Study 1 explores the prevalence of distinct NIHS countermeasures in collaborative R&D practice. Based on 32 interviews and three focus group meetings with R&D employees, we find that a broad array of primarily direct NIHS countermeasures is employed in R&D practice. Study 2 addresses the scarcity of scholarly and managerial insights on indirect NIHS countermeasures by testing the effectiveness of perspective taking as a debiasing technique to contain negative attitudes at the level of the individual. Based on quantitative survey data from 565 global R&D projects, it provides empirical evidence not only for the prevalence and negative effects of NIHS on project success as mediated by external knowledge absorption, but also for the effectiveness of perspective taking as an exemplary indirect NIHS countermeasure

Extension of the generalized multipole technique to three-dimensional anisotropic scatterers

New expansions are derived for the simulation of three-dimensional anisotropic scatterers with the generalized multipole technique (GMT). This extension of the GMT makes possible the investigation of subtle phenomena such as the interaction of light with realistic crystals or magneto-optic materials. (C) 1998 Optical Society of America

Electromagnetic scattering in polarizable backgrounds

We develop a fully vectorial formalism for the investigation of electromagnetic scattering in polarizable backgrounds, i.e., where the scatterers are not in vacuum but situated in a medium with a dielectric permittivity different from unity. Our approach is based on the Green's tensor technique and the corresponding Green's tensors for two-dimensional (2D) and three-dimensional (3D) systems are developed. The analysis of 2D systems is not restricted to the case where transverse electric (TE) and transverse magnetic (TM) modes are decoupled, but treated in a general manner. Practical examples illustrate the application of the method: scattering by a microcavity for two dimensions and color formation in opal for three dimensions

Increasing the performance of the coupled-dipole approximation: A spectral approach

We show that it is possible to increase the performance of the coupled-dipole approximation (CDA) for scattering by using concepts from the sampling theory. In standard CDA, the source in each discretized cell is represented by a point dipole and the corresponding scattered field given by Green's tensor. In the present approach, the source has a certain spatial extension, and the corresponding Green's tensor must be redefined. We derive these so-called filtered Green's tensors for one-dimensional (1-D), two-dimensional (2-D), and three-dimensional (3-D) systems, which forms the basis of our new scheme: the filtered coupled-dipole technique (FCD)

Diffractive Phenomena and Shadowing in Deep-Inelastic Scattering

Shadowing effects in deep-inelastic lepton-nucleus scattering probe the mass spectrum of diffractive leptoproduction from individual nucleons. We explore this relationship using current experimental information on both processes. In recent data from the NMC and E665 collaboration, taken at small x << 0.1 and Q^2 < 1 GeV^2, shadowing is dominated by the diffractive excitation and coherent interaction of low mass vector mesons. If shadowing is explored at small x > 1 GeV^2 as discussed at HERA, the situation is different. Here dominant contributions come from the coherent interaction of diffractively produced heavy mass states. Furthermore we observe that the energy dependence of shadowing is directly related to the mass dependence of the diffractive production cross section for free nucleon targets.Comment: 12 pages Latex, 8 figure

Economic Implications of Additive Manufacturing and the Contribution of MIS

This is the author accepted manuscript. The final version is available from Springer at http://link.springer.com/article/10.1007%2Fs12599-015-0374-4

Resummation of nuclear enhanced higher twist in the Drell Yan process

We investigate higher twist contributions to the transverse momentum broadening of Drell Yan pairs in proton nucleus collisions. We revisit the contribution of matrix elements of twist-4 and generalize this to matrix elements of arbitrary twist. An estimate of the maximal nuclear broadening effect is derived. A model for nuclear enhanced matrix elements of arbitrary twist allows us to give the result of a resummation of all twists in closed form. Subleading corrections to the maximal broadening are discussed qualitatively.Comment: 10 pages, 5 figures; v2: minor changes in text, acknowledgement added; v3: mistake in fig. 1 correcte

Investigation of slowing down and charge-exchange of nickel and uranium ions in gases and solids in the energy range (60 - 200) MeV/u

In this thesis new slowing down and charge-state measurements will be presented in the energy range of (60 - 200) MeV/u. These measurements were done using the Fragment Separator (FRS) facility at GSI in Darmstadt. The presented data were taken during two experimental runs. The experiments were divided into two parts. In the first part a 200 MeV/u Ni27+ beam was used. The evolution of charge states as a function of the target thickness was investigated covering both the non-equilibrium and equilibrium region. This was done with various mono-atomic materials (Z2 = 6, 7, 10, 13, 18, 22) and compound materials (ethylene, polyethylene and polypropylene). From the measured charge-state distributions the one-electron ionization and capture cross sections have been extracted. A 40 % gas-solid difference is observed in the ionization cross sections for the mono-atomic materials. In the compound materials a 30 % difference is observed between ethylene and the polymers. The experimental cross sections for the mono-atomic materials have been compared with theoretical calculations [1, 2]. The theoretical ionization cross sections agree quite well with the corresponding experimental ionization cross sections. In the gaseous targets the agreement between experiment and theory is better than 3 %. For the capture cross sections the agreement between experiment and theory is also very good for the lighter target materials (Z2 <= 7). For the heavier targets large deviations up to one order of magnitude are observed. These deviations are due to the increasing importance of the non-radiative capture channel in heavier target materials which is quite difficult to calculate accurately. The results motivate for further refinement of the theory in this energy region. In the second part 3 different uranium beams were used with initial energies of 61 MeV/u (U86+ incident), 85 MeV/u (U73+ incoming) and 200 MeV/u (U81+ incident) to measure the evolution of the charge states again and the energy loss as a function of the target thickness in the same materials as used in the first part plus some additional mono-atomic materials Z2 = 29, 36, 47, 54. From the measured charge-state distributions and energy losses the mean charges and stopping forces have been extracted. At 61 MeV/u we observe a gas-solid difference in the mean charge of up to 4 charge states for the mono-atomic materials. The corresponding stopping powers (forces) at the same specific energy only show a gas-solid difference for light materials (Z2 <= 7). The stopping forces are compared with calculations done with the PASS code [3, 4], ATIMA code [5] and the Hubert et al. tables [6]. The agreement is quite good between experiment and theory. The PASS code predicts by using the experimental mean charges a gas-solid difference in the stopping force for the heavier target materials. In the data at 200 MeV/u there is a gas-solid difference in the ionization rate for U81+ ions similar to the Ni27+ results.In dieser Dissertation werden neue Ladungsverteilungen und Energieverlustmessungen präsentiert. Diese Messungen wurden am Fragment Separator (FRS) bei der GSI in Darmstadt durchgeführt. Die Daten, die hier vorgestellt werden, wurden in zwei Experimenten aufgenommen. Die Experimente bestanden aus zwei Teilen. Im ersten Teil wurde mit einem 200 MeV/u Ni27+ Strahl gemessen. Ziel dieser Messung war die Entwicklung der Ladungsverteilung als Funktion der Targetdicke vom Nichtgleichgewicht bis Gleichgewicht zu untersuchen. Dies wurde mit verschiedenen Targets gemacht (Z2 = 6, 7, 10, 13, 18, 22, Äthylen, Polyäthylen und Polypropylen). Von den gemessenen Ladungsverteilung konnten die Umladungsquerrschnitte für Elektroneneinfang und -verlust extrahiert werden. Ein Gas-Festkörper Effekt von 40 % wurde im Ionizationsquerrschnitt für die monoatomaren (reinen Elemente) Targets gemessen. Im Äthylen und den Polymeren (Polyäthylen und Polypropylen) war ein Effekt von 30 % zu sehen. Die experimentellen Umladungsquerrschnitte für die monoatomaren Targets wurden mit theoretischen Rechnungen von A. Surzhykov und S. Fritzsche [1] und V. P. Shevelko [2] verglichen. In der Ionization stimmen die theoretischen Rechnungen mit den experimentellen Werten gut überein. In den Gastargets ist die Übereinstimmung besser als 3 %. Im Elektroneneinfang gibt es gute Übereinstimmung zwischen Experiment und Theorie bei den leichten Targets (Z2 <= 7), bei den schweren Targets gibt es grosse Abweichungen bis zu einer Grössenordnung. Diese Abweichung kommt zustande, weil der nicht-radiative Querrschnitt einen grösseren Anteil hat bei den schweren Targets und dieser Teil sehr schwer theoretisch zu rechnen ist. Die Ergebnisse sind eine Motivation für Verbesserungen in der Theorie im diesen Energiebereich. Im zweiten Teil wurde ein Uranstrahl bei drei verschiedenen Energien benutzt, diese waren 61 MeV/u mit 86+ als Eingangsladungszustand, 85 MeV/u mit 73+ als Eingangsladungszustand und 200 MeV/u mit 81+ als Eingangsladungszustand. Ziel dieser Messung war es wiederum, die Entwicklung der Ladungsverteilung zu untersuchen und auch Energieverluste zu messen. Dieselben Targets wurden benutzt und zusätzlich wurden folgende Targets vermessen Z2 = 29, 36, 47, 54. Von den gemessenen Ladungsverteilungen und Energieverlusten wurde die mittlere Ladung und das Bremsvermögen bestimmt. Bei 61 MeV/u ist ein Gas-Festkörper Effekt in der mittleren Ladung bei den monoatomaren Targets zu sehen. Der Effekt hat eine Grösse von fast 4 Ladungen. Das dazu gehörige Bremsvermögen zeigt nur einen Gas-Festkörper Effekt bei den leichteren Targets (Z2 <= 7). Die experimentellen Werte wurden mit dem PASS Programm [3, 4], dem ATIMA Programm [5] und den Hubert et al. Tabellen [6] verglichen. Die theoretischen Rechnungen von den Programmen stimmen mit den experimentellen Werten gut überein. PASS sagt einen Gas-Festkörper Effekt bei den schwereren Targets voraus, weil experimentelle Ladungen als Eingangsparameter benutzt wurden. Bei der 200 MeV/u Messung wurde ein Gas-Festkörper Unterschied in der Ionizationsrate in der Entwicklung des U81+ Ladungszustand beobachtet, ähnlich wie in der Ni27+ Messung

Charmonium suppression from purely geometrical effects

The extend to which geometrical effects contribute to the production and suppression of the $J/\psi$ and $q\bar{q}$ minijet pairs in general is investigated for high energy heavy ion collisions at SPS, RHIC and LHC energies. For the energy range under investigation, the geometrical effects referred to are shadowing and anti-shadowing, respectively. Due to those effects, the parton distributions in nuclei deviate from the naive extrapolation from the free nucleon result; $f_{A}\neq A f_{N}$. The strength of the shadowing/anti-shadowing effect increases with the mass number. The consequences of gluonic shadowing effects for the $x_F$ distribution of $J/\psi$'s at $\sqrt s =20$ GeV, $\sqrt s =200$ GeV and $\sqrt s =6$ TeV are calculated for some relevant combinations of nuclei, as well as the $p_T$ distribution of minijets at midrapidity for $N_f=4$ in the final state.Comment: corrected some typos, improved shadowing ratio