Silicon photomultiplier arrays - a novel photon detector for a high resolution tracker produced at FBK-irst, Italy

A silicon photomultiplier (SiPM) array has been developed at FBK-irst having 32 channels and a dimension of 8.0 x 1.1 mm^2. Each 250 um wide channel is subdivided into 5 x 22 rectangularly arranged pixels. These sensors are developed to read out a modular high resolution scintillating fiber tracker. Key properties like breakdown voltage, gain and photon detection efficiency (PDE) are found to be homogeneous over all 32 channels of an SiPM array. This could make scintillating fiber trackers with SiPM array readout a promising alternative to available tracker technologies, if noise properties and the PDE are improved

On the basic mechanism of Pixelized Photon Detectors

A Pixelized Photon Detector (PPD) is a generic name for the semiconductor devices operated in the Geiger-mode, such as Silicon PhotoMultiplier and Multi-Pixel Photon Counter, which has high photon counting capability. While the internal mechanisms of the PPD have been intensively studied in recent years, the existing models do not include the avalanche process. We have simulated the multiplication and quenching of the avalanche process and have succeeded in reproducing the output waveform of the PPD. Furthermore our model predicts the existence of dead-time in the PPD which has never been numerically predicted. For serching the dead-time, we also have developed waveform analysis method using deconvolution which has the potential to distinguish neibouring pulses precisely. In this paper, we discuss our improved model and waveform analysis method.Comment: 4pages, 5figures, To appear in the proceedings of 5th International Conference on New Developments in Photodetection (NDIP08), Aix-les-Bains, France, 15-20 Jun 200

L’ASDI e le politiche di governance per lo sviluppo per il Distretto della Sedia

Associazione per lo Sviluppo del Distretto della Sedia (ASDI Sedia

Witten index and phase diagram of compactified N=1 supersymmetric Yang-Mills theory on the lattice

Owing to confinement, the fundamental particles of N=1 Supersymmetric Yang-Mills (SYM) theory, gluons and gluinos, appear only in colourless bound states at zero temperature. Compactifying the Euclidean time dimension with periodic boundary conditions for fermions preserves supersymmetry, and confinement is predicted to persist independently of the length of the compactified dimension. This scenario can be tested non-perturbatively with Monte-Carlo simulations on a lattice. SUSY is, however, broken on the lattice and can be recovered only in the continuum limit. The partition function of compactified N=1 SYM theory with periodic fermion boundary conditions corresponds to the Witten index. Therefore it can be used to test whether supersymmetry is realized on the lattice. Results of our recent numerical simulations are presented, supporting the disappearance of the deconfinement transition in the supersymmetric limit and the restoration of SUSY at low energies.Comment: 7 pages, 3 figures, Proceedings of the 33rd International Symposium on Lattice Field Theory (Lattice 2015), 14-18 July 2015, Kobe International Conference Center, Kobe, Japa

La Segunda Internacional en su relación con Marx y Engels a propósito de la cuestión nacional (1889-1914)

La interpretació que sobre les nacions van poder oferir Marx i Engels va restar inconclusa, quedant lluny de veure's cristal·litzada en fórmules analítiques precises a partir de les quals fos possible combinar la qüestió nacional en un pla d'acció revolucionari. Tanmateix, aquests primers esbossos sobre les nacions van ser recollits i ampliats pels socialistes de la Segona Internacional. L'objectiu d'aquest treball és recuperar analíticament les primeres interpretacions que van sorgir en el si del socialisme europeu a la fi del segle XIX i començaments del segle XX al voltant del procés de conformació d'aquella nova relació dialèctica intervinguda entre la lluita nacional i la lluita de classes. Amb aquest propòsit seran abordades les produccions intel·lectuals més destacades del període, la qual cosa permetrà actualitzar des d'una perspectiva històrica el nucli dels intensos debats experimentats pel marxisme europeu que van aconseguir el seu punt d'ebullició fa exactament un segle al voltant del sorgiment de les nacions i les nacionalitats i les seves possibles vinculacions amb els plans per aconseguir l'emancipació dels treballadors.Marx and Engels’ interpretation of the nations was left inconclusive, thus remaining far from crystallising into precise analytic formulas from which it would be possible to combine the national question into a revolutionary action plan. Nevertheless, these first sketches around the nations were compiled and expanded on by the Second International socialists. The aim of this paper is to analytically recover the first interpretations that emerged within the European socialism in the late nineteenth century and early twentieth century around the process of forming this new mediated dialectical relationship between the national struggle and class struggle. To this purpose, I will address the most salient intellectual productions of the period, which will update from a historical perspective the core of the intense debates experienced by the European Marxism, which reached their boiling point exactly a century ago during the rise of nations and nationalities and their possible links with plans to achieve the emancipation of workers.La interpretación que sobre las naciones pudieron brindar Marx y Engels resultó inconclusa, quedando lejos de verse cristalizada en fórmulas analíticas precisas a partir de las cuales fuera posible combinar la cuestión nacional en un plan de acción revolucionario. No obstante, estos primeros bocetos en torno de las naciones fueron recogidos y ampliados por los socialistas de la Segunda Internacional. El objetivo de este trabajo es recuperar analíticamente las primeras interpretaciones que emergieron en el seno del socialismo europeo a finales del siglo XIX y comienzos del siglo XX alrededor del proceso de conformación de aquella novedosa relación dialéctica mediada entre la lucha nacional y la lucha de clases. Con este propósito serán abordadas las producciones intelectuales más salientes del período, lo que permitirá actualizar desde una perspectiva histórica el núcleo de los intensos debates experimentados por el marxismo europeo que alcanzaron su punto de ebullición hace exactamente un siglo alrededor del surgimiento de las naciones y las nacionalidades y sus posibles vinculaciones con los planes para alcanzar la emancipación de los trabajadores

Phase structure of the N=1 supersymmetric Yang-Mills theory at finite temperature

Supersymmetry (SUSY) has been proposed to be a central concept for the physics beyond the standard model and for a description of the strong interactions in the context of the AdS/CFT correspondence. A deeper understanding of these developments requires the knowledge of the properties of supersymmetric models at finite temperatures. We present a Monte Carlo investigation of the finite temperature phase diagram of the N=1 supersymmetric Yang-Mills theory (SYM) regularised on a space-time lattice. The model is in many aspects similar to QCD: quark confinement and fermion condensation occur in the low temperature regime of both theories. A comparison to QCD is therefore possible. The simulations show that for N=1 SYM the deconfinement temperature has a mild dependence on the fermion mass. The analysis of the chiral condensate susceptibility supports the possibility that chiral symmetry is restored near the deconfinement phase transition.Comment: 26 pages, 12 figure

La compleja relación entre la dirección del Partido Comunista de la Argentina y la representación de la Comintern ante la ruptura de 1928

En su rol como jefe del Secretariado Latino de la Comintern, Jules Humbert-Droz señalaba en 1928 que el origen de la crisis que atravesaba el Partido Comunista de la Argentina desde el año anterior radicaba en la convivencia de dos facciones enfrentadas que redundaba en la inexistencia de un verdadero Comité Central. El conflicto entre una minoría de la dirección del partido argentino liderada por José Penelón y una mayoría encabezada por Rodolfo Ghioldi decantó en el pedido formal por parte de este último grupo para que la Comintern decidiera de qué manera se debía reestablecer la estabilidad intrapartidaria. Partiendo de esta situación problemática se plantea en este artículo que fue la misma dirección mayoritaria del PCA la que, al solicitar la intervención del Comité Ejecutivo cominterniano en los asuntos internos de la sección argentina, condujo a un alineamiento dogmático con la Internacional Comunista que hubo de marcar la trayectoria del PCA durante todo el tiempo transcurrido hasta la disolución de aquella.In his role as head of the Latin Secretariat of the Communist International, Jules Humbert-Droz poin - ted out in 1928 that the origin of the crisis the Communist Party of Argentina was going through since the previous year stemmed from the coexistence of two opposing factions and the lack of a true Central Committee. The conflict between a minority in the leadership of the Argentine party led by José Penelón and a majority conducted by Rodolfo Ghioldi resulted in the formal request of the latter group for the Comintern to decide the path to re-establishing the intra-party stability. Taking into consideration this problem, the present article hypothesises that it was the majority of the leadership of the PCA which, by requesting intervention from the Executive Committee of the Comintern in the internal affairs of the Argentine section, conducted a dogmatic alignment with the Communist International, thus marking the path for the PCA until its dissolution.Fil: Piemonte, Víctor Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto de Historia Argentina y Americana ; Argentin