320 resultados para Kaon-electroproduction, strangeness, SiPM


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The E01-011 experiment at Jefferson Laboratory (JLab) studied light-to-medium mass Λ hypernuclei via the AZ + e → [special characters omitted] + e' + K+ electroproduction reaction. Precise measurement of hypernuclear ground state masses and excitation energies provides information about the nature of hyperon-nucleon interactions. Until recently, hypernuclei were studied at accelerator facilities with intense π+ and K- meson beams. The poor quality of these beams limited the resolution of the hypernuclear excitation energy spectra to about 1.5 MeV (FWHM). This resolution is not sufficient for resolving the rich structure observed in the excitation spectra. By using a high quality electron beam and employing a new high resolution spectrometer system, this study aims to improve the resolution to a few hundred keV with an absolute precision of about 100 keV for excitation energies. In this work the high-resolution excitation spectra of [special characters omitted], and [special characters omitted] hypernuclei are presented. In an attempt to emphasize the presence of the core-excited states we introduced a novel likelihood approach to particle identification (PID) to serve as an alternative to the commonly used standard hard-cut PID. The new method resulted in almost identical missing mass spectra as obtained by the standard approach. An energy resolution of approximately 400–500 keV (FWHM) has been achieved, an unprecedented value in hypernuclear reaction spectroscopy. For [special characters omitted] the core-excited configuration has been clearly observed with significant statistics. The embedded Λ hyperon increases the excitation energies of the 11B nuclear core by 0.5–1 MeV. The [special characters omitted] spectrum has been observed with significant statistics for the first time. The ground state is bound deeper by roughly 400 keV than currently predicted by theory. Indication for the core-excited doublet, which is unbound in the core itself, is observed. The measurement of [special characters omitted] provides the first study of a d-shell hypernucleus with sub-MeV resolution. Discrepancies of up to 2 MeV between measured and theoretically predicted binding energies are found. Similar disagreement exists when comparing to the [special characters omitted] mirror hypernucleus. Also the core-excited structure observed between the major s-, p- and d-shell Λ orbits is not consistent with the available theoretical calculations. In conclusion, the discrepancies found in this study will provide valuable input for the further development of theoretical models.

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Questa tesi si inserisce nell’ambito del progetto WA104-NESSiE al CERN per il quale era richiesto lo sviluppo di un tracciatore di particelle cariche da utilizzare in presenza di campi magnetici e avente una risoluzione sulla posizione ricostruita di 1-2 mm. Il lavoro di tesi ha riguardato l'analisi dei dati raccolti con un prototipo del tracciatore composto da barre di scintillatori a sezione triangolare, accoppiati a SiPM i cui segnali sono acquisiti in modalità analogica. Il prototipo è stato esposto a particelle cariche presso la linea di fascio T9 del PS del CERN nel maggio 2016. La catena di analisi è stata validata con dati provenienti da una simulazione Monte Carlo basata su Geant4 che fornisce la risposta del tracciatore al passaggio di particelle cariche (pioni e muoni) a diversi impulsi (1-10 GeV/c). Successivamente, è stata fatta un'analisi preliminare dei dati reali e un confronto con la simulazione Monte Carlo. La risoluzione ottenuta per pioni di 5 GeV è di ∼ 2 mm, compatibile con il valore ottenuto dalla simulazione Monte Carlo di ∼ 1.5 mm. Questi risultati sono stati ricavati analizzando una frazione degli eventi acquisiti durante il test beam. Una misura più accurata della risoluzione del tracciatore può essere ottenuta introducendo alcune correzioni, come ad esempio l’allineamento dei piani, la ricalibrazione dei segnali dei singoli canali e, infine, analizzando l’intero campione.

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The Borg, a collective of humanoid cyborgs linked together in a hive-mind and modeled on the earthly superorganisms of ant colonies and beehives, has been the most feared alien race in the Star Trek universe. The formidable success of the Borg in assimilating their foes corresponds to the astounding success of superorganisms in our own biosphere. Yet the Borg also serves as a metaphor for another collective of biological entities known as the corporation. In the Anthropocene epoch, corporations have become the most powerful force on the planet; their influence on the social world and the environment exceeds any government and may determine the continued sustainability of human life. Corporations have been described as people and as machines, but neither metaphor accurately describes their essence or contributes to an understanding that might resist their power. This paper reframes our understanding of the corporation by examining the metaphors that are used to describe it, and by suggesting an entirely new metaphor viewing the Borg and the corporation through the lens of sociobiology. I will argue that the corporation is a new form of superorganism that has become the dominant species on the planet and that the immense, intractable power of a globalized, corporate hive-mind has become the principal obstacle to addressing the planetary emergency of climate change. Reframing our metaphoric understanding of corporations as biological entities in the planetary biosphere may enable us to imagine ways to resist their increasing dominance and create a sustainable future. 

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This book is a synthesizing reflection on the Holocaust commemoration, in which space becomes a starting point for discussion. The author understands space primarily as an amalgam of physical and social components, where various commemorative processes may occur. The first part of the book draws attention to the material aspect of space, which determines its character and function. Material culture has been a long ignored and depreciated dimension of human culture in the humanities and social sciences, because it was perceived as passive and fully controlled by human will, and therefore insignificant in the course of social and historical processes. An example of the Nazi system perfectly illustrates how important were the restrictions and prohibitions on the usage of mundane objects, and in general, the whole material culture in relation to macro and micro space management — the state, cities, neighborhoods and houses, but also parks and swimming pools, factories and offices or shops and theaters. The importance of things and space was also clearly visible in exploitative policies present in overcrowded ghettos and concentration and death camps. For this very reason, when we study spatial forms of Holocaust commemoration, it should be acknowledged that the first traces, proofs and mementoes of the murdered were their things. The first "monuments" showing the enormity of the destruction are thus primarily gigantic piles of objects — shoes, glasses, toys, clothes, suitcases, toothbrushes, etc., which together with the extensive camps’ space try to recall the scale of a crime impossible to understand or imagine. The first chapter shows the importance of introducing the material dimension in thinking about space and commemoration, and it ends with a question about one of the key concepts for the book, a monument, which can be understood as both object (singular or plural) and architecture (sculptures, buildings, highways). However, the term monument tends to be used rather in a later and traditional sense, as an architectural, figurative form commemorating the heroic deeds, carved in stone or cast in bronze. Therefore, the next chapter reconstructs this narrower line of thinking, together with a discussion about what form a monument commemorating a subject as delicate and sensitive as the Holocaust should take on. This leads to an idea of the counter-monument, the concept which was supposed to be the answer to the mentioned representational dilemma on the one hand, and which would disassociate it from the Nazi’s traditional monuments on the other hand. This chapter clarifies the counter-monument definition and explains the misunderstandings and confusions generated on the basis of this concept by following the dynamics of the new commemorative form and by investigating monuments from the ‘80s and ‘90s erected in Germany. In the next chapter, I examine various forms of the Holocaust commemoration in Berlin, a city famous for its bold, monumental, and even controversial projects. We find among them the entire spectrum of memorials – big, monumental, and abstract forms, like Peter Eisenman’s Memorial to the Murdered Jews of Europe or Daniel Liebeskind’s Jewish Museum Berlin; flat, invisible, and employing the idea of emptiness, like Christian Boltanski’s Missing House or Micha Ullman’s Book Burning Memorial; the dispersed and decentralized, like Renata Stih and Frieder Schnock’s Memory Places or Gunter Demnig’s Stumbling Blocks. I enrich descriptions of the monuments by signaling at this point their second, extended life, which manifests itself in the alternative modes of (mis)use, consisting of various social activities or artistic performances. The formal wealth of the outlined projects creates a wide panorama of possible solutions to the Holocaust commemoration problems. However, the discussions accompanying the building of monuments and their "future life" after realization emphasize the importance of the social component that permeates the biography of the monument, and therefore significantly influences its foreseen design. The book also addresses the relationship of space, place and memory in a specific situation, when commemoration is performed secretly or remains as unrealized potential. Although place is the most common space associated with memory, today the nature of this relationship changes, and is what indicates popularity and employment of such terms as Marc Augé’s non-places or Pierre Nora’s site of memory. I include and develop these concepts about space and memory in my reflections to describe qualitatively different phenomena occurring in Central and Eastern European countries. These are unsettling places in rural areas like glades or parking lots, markets and playgrounds in urban settings. I link them to the post-war time and modernization processes and call them sites of non-memory and non-sites of memory. Another part of the book deals with a completely different form of commemoration called Mystery of memory. Grodzka Gate - NN Theatre in Lublin initiated it in 2000 and as a form it situates itself closer to the art of theater than architecture. Real spaces and places of everyday interactions become a stage for these performances, such as the “Jewish town” in Lublin or the Majdanek concentration camp. The minimalist scenography modifies space and reveals its previously unseen dimensions, while the actors — residents and people especially related to places like survivors and Righteous Among the Nations — are involved in the course of the show thanks to various rituals and symbolic gestures. The performance should be distinguished from social actions, because it incorporates tools known from religious rituals and art, which together saturate the mystery of memory with an aura of uniqueness. The last discussed commemoration mode takes the form of exposition space. I examine an exhibition concerning the fate of the incarcerated children presented in one of the barracks of the Majdanek State Museum in Lublin. The Primer – Children in Majdanek Camp is unique for several reasons. First, because even though it is exhibited in the camp barrack, it uses a completely different filter to tell the story of the camp in comparison to the exhibitions in the rest of the barracks. For this reason, one experiences immersing oneself in all subsequent levels of space and narrative accompanying them – at first, in a general narrative about the camp, and later in a specifically arranged space marked by children’s experiences, their language and thinking, and hence formed in a way more accessible for younger visitors. Second, the exhibition resigns from didacticism and distancing descriptions, and takes an advantage of eyewitnesses and survivors’ testimonies instead. Third, the exhibition space evokes an aura of strangeness similar to a fairy tale or a dream. It is accomplished thanks to the arrangement of various, usually highly symbolic material objects, and by favoring the fragrance and phonic sensations, movement, while belittling visual stimulations. The exhibition creates an impression of a place open to thinking and experiencing, and functions as an asylum, a radically different form to its camp surrounding characterized by a more overwhelming and austere space.

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The leading approach to everyday aesthetics for the past few decades has departed from analytic philosophical grounds, generating some tensions or dichotomies regarding its foundational cornerstones: the ordinary vs. extraordinary character of everyday aesthetic experience, contextual familiarity vs. strangeness, object vs. processual orientation, etc. Although John Dewey has been widely acclaimed as a sort of foundational figure for this burgueoning sub-discipline of aesthetics, maybe not enough emphasis has been laid on his very different pragmatist approach. In this regard, his reliance on Hegelian cum Darwinian premises might allow for a connection with other branches of continental as well as Asian philosophies, from which also some research on everyday aesthetics has been made. It is from this wider ontological framework that the notion of rhythm could be vindicated as a pivotal aspect of the aesthetic dimension of our everyday lives. Dewey deals extensively with it in Art as Experience, conceiving it as a sort of pattern of accomplished experiences, accounting also for his naturalistic approach and art and life continuity thesis. On the other hand, neo-pragmatist exponent Richard Shusterman, among others, has posited links of connection between Pragmatist aesthetics and East-Asian philosophies. Particularly, Dewey’s resonances with Asian philosophies have been studied, with a preeminence on the notions of harmony and rhythm. This paper will depart from the analysis of the notion of rhythm in Dewey’s philosophy, trying to hint at some possible developments of its implications. Particularly, it will expand on some East Asian paralelisms to his philosophy, trying to link them with the notion of rhythm as an epitomizing ground for the conjunction of the extraordinary (art) and the ordinary (life).