Remarks on the analytic structure of supersymmetric effective actions

We study the effective superpotential of N=1 supersymmetric gauge theories with a mass gap, whose analytic properties are encoded in an algebraic curve. We propose that the degree of the curve equals the number of semiclassical branches of the gauge theory. This is true for supersymmetric QCD with one adjoint and polynomial superpotential, where the two sheets of its hyperelliptic curve correspond to the gauge theory pseudoconfining and higgs branches. We verify this proposal in the new case of supersymmetric QCD with two adjoints and superpotential V(X)+XY^2, which is the confining phase deformation of the D_{n+2} SCFT. This theory has three kinds of classical vacua and its curve is cubic. Each of the three sheets of the curve corresponds to one of the three semiclassical branches of the gauge theory. We show that one can continuously interpolate between these branches by varying the couplings along the moduli space.Comment: 49 pages, 3 figures, harvmac; typos correcte

Selective laser melting of H13 tool steel powder: effect of process parameter on complex part production

This research work presents the investigation of H13 tool steel powder in the production of parts characterized by complex features via selective laser melting. The authors proposed a benchmark geometry with 40 mm nominal height, self-supported overhanging structure and internal channels. To investigate powder printability and process capabilities, an experimental campaign was designed as a function of laser power, scan speed and hatching distance. Full dense parts exhibiting 99.92% internal density have been achieved by imposing a laser power equal to 150 W, a scan speed equal to 500 mm/s and a hatching distance equal to 120 µm, while high geometrical accuracy in terms of no material drops along sample edges and low-dimensional deviations of the realized sloping surfaces (i.e., + 0.23° and − 0.90° for nominal 35° and 40° overhang, respectively) has been achieved for 150 W, 1000 mm/s, and 100 µm. Findings open the way to use SLM technology in the design of advanced cutting tool solutions

Industrial policies in Europe: an introduction

As guest editors of this Special Issue of PE/JEP we have selected a small number of rather detailed assessment of contemporary history of domestic industrial policies in the international context. The four papers included in this Special Issue can be seen as three case studies of “sectoral” innovation policies (broad band, wind energy, biotechnology) with a strong emphasis on country institutional features and policy instruments, together with one “horizontal” case of industrial policy in a specific country context (innovative startups in Italy). The heterogeneous theoretical background (industrial organization, evolutionary theory of the firm, economics of innovation, development) provides a somewhat unifying hidden thread of these case studies, without becoming a subject of analysis per se. This approach has been our intentional editorial choice and we are fully aware of its limitations. After very short non-technical summaries of the four papers (Section 1) we try to present a rather synthetic assessment of our personal views (largely shared among us even with partial minor disagreements) about the increasingly hot debate on the nature, limitations and desirable perspectives of industrial policy today. We argue for a non-ideological forward-looking role of governments as active players in helping domestic entrepreneurial resources not only to fully exploit inherited comparative advantages but also to face structural uncertainties and discover own potential competitive advantages in a rapidly changing international context (Section 2)

Chiral Rings, Anomalies and Electric-Magnetic Duality

We study electric-magnetic duality in the chiral ring of a supersymmetric U(N_c) gauge theory with adjoint and fundamental matter, in presence of a general confining phase superpotential for the adjoint and the mesons. We find the magnetic solution corresponding to both the pseudoconfining and higgs electric vacua. By means of the Dijkgraaf-Vafa method, we match the effective glueball superpotentials and show that in some cases duality works exactly offshell. We give also a picture of the analytic structure of the resolvents in the magnetic theory, as we smoothly interpolate between different higgs vacua on the electric side.Comment: 54 pages, harvmac. v2: typos correcte

Threshold Photo/Electro Pion Production - Working Group Summary

We summarize the pertinent experimental and theoretical developments in the field of pion photo- and electroproduction in the threshold region. We discuss which experiments and which calculations should be done/performed in the future.Comment: plain TeX (macro included), 6pp, summary talk presented at the workshop on "Chiral Dynamics: Theory and Experiments", MIT, July 25-29, 199

An electromagnetic shashlik calorimeter with longitudinal segmentation

A novel technique for longitudinal segmentation of shashlik calorimeters has been tested in the CERN West Area beam facility. A 25 tower very fine samplings e.m. calorimeter has been built with vacuum photodiodes inserted in the first 8 radiation lengths to sample the initial development of the shower. Results concerning energy resolution, impact point reconstruction and electron/pion separation are reported.Comment: 13 pages, 12 figure