88 research outputs found

    The 1953 Cosmic Ray Conference at Bagneres de Bigorre

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    The cosmic ray conference at Bagn`eres de Bigorre in July, 1953 organized by Patrick Blackett and Louis Leprince-Ringuet was a seminal one. It marked the beginning of sub atomic physics and its shift from cosmic ray research to research at the new high energy accelerators. The knowledge of the heavy unstable particles found in the cosmic rays was essentially correct in fact and interpretation and defined the experiments that needed to be carried out with the new accelerators. A large fraction of the physicists who had been using cosmic rays for their research moved to the accelerators. This conference can be placed in importance in the same category as two other famous conferences, the Solvay congress of 1927 and the Shelter Island Conference of 1948

    Ghost-free higher-derivative theory

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    We present an example of the quantum system with higher derivatives in the Lagrangian, which is ghost-free: the spectrum of the Hamiltonian is bounded from below and unitarity is preserved.Comment: 13 pages, 1 figur

    Chiral anomalies in higher-derivative supersymmetric 6D gauge theories

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    We show that the recently constructed higher-derivative 6D SYM theory involves an internal chiral anomaly breaking gauge invariance. The anomaly is cancelled when adding to the theory an adjoint matter hypermultiplet.Comment: A missed contribution added. The article is rather essentially reshuffle

    A lapa do Bugio

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    A jazida pré-histórica do Bugio constitui uma das mais importantes grutas sepulcrais da faixa estremenha. Encontrava-se intacta à data das primeiras escavações, realizadas em 1957 e 1958. Vicissitudes várias que motivaram a dissolução da primeira equipa e favoreceram diversas depredações, entretanto realizadas, impediram que, antes do recomeço dos trabalhos, em 1966, mesmo dos materiais recuperados, se pudessem extrair todas as informações neles potencialmente contidas. Foi possível, a partir do estudo exaustivo do espólio conservado no Museu de Sesimbra e no recolhido nas escavações de 1966, estabelecer a seguinte sucessão cronológica-cultural: Primeira ocupação - corresponde talvez à ocupação mais importante, integrável no Neolítico recente-final estremenho. Estreitas analogias com o "horizonte dolménico" identificado na vizinha Lapa do Fumo e datado pelo rádio-carbono de 3090 ± 160 a. C. (SERRÃO,1978). A datação realizada no Bugio deu 2800 ± 45 a.C. Segunda ocupação- corresponde muito provavelmente a momento inicial (ou pleno) do Calcolítico, definido pela presença de raros produtos, como o recipiente de osso recolhido na sep. 7 e "ídolos" de calcário, de osso e marfim. Terceira ocupação - Calcolítico final, campaniforme - representada pelos Grupos de Palmela e Inciso. Trata-se da ocupação menos importante, excessivamente valorizada em trabalhos anteriores, talvez pela grande dispersão de fragmentos cerâmicos que não ultrapassam, contudo, nove recipientes (alguns deles representados por apenas um fragmento): taças em calote - (I), de bordo espessado - (I), de tipo Palmela - (I), caçoilas acampanadas - (2), e vasos campaniformes - (2), além de dois recipientes de tipologia mal definida.Le gisement préhistorique de Bugio est l 'une des plus importantes grottes sépulcrales du littoral de l'Estrémadure. Elle a été trouvée intacte lors des premières fouilles, réalisées en 1957 et 1958. Diverses vicissitudes, qui devaient aboutir à la dissolution de la première équipe de fouilleurs et favoriser le pillage du site, empêchèrent la difusion de toute information avant la reprise des travaux en 1966, même sur le matériel récupéré. A partir de l' étude exhaustive du mobilier conservé au Musée de Sesimbra et de celui qui a été découvert en 1966, on a pu établir les niveaux chronologiques suivants: Première occupation, peut-être la plus importante, s'intégrant dans le Néolithique récent et final de l'Estrémadure, présentant d' étroites analogies avec "l'horizon dolménique" identifié sur le site voisin de Lapa do Fumo, daté de 3090 ± 160 a.C. par radio-carbone (SERRÃO, 1978). La datation obtenue à Bugio est de 2800 ± 45 a.C.. Seconde occupation, correspondant très probablement à la phase initiale ou médiane du Chalcolithique, définie par de rares productions, comme le récipient en os recueilli dans la sépulture 7 et les "idoles" en calcaire, en os et en ivoire. Troisième occupation (Chalcolithique final, Campaniforme) représentée par les Groupes de Palmela et incisé. Il s'agit d'une occupation moins importante, surévaluée dans les travaux antérieurs, peut-être en raison de la grande dispersion des fragments de céramiques qui ne correspondaient, cependant, qu'à neuf récipients: coupes en calotte (1 ), coupes au bord épais (1), coupes de type de Palmela (1), casseroles en forme de cloche (2), vases campaniformes (2) et deux récipients à la typologie mal définie

    On the free field realization of the osp(1|2) current algebra

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    The free field representation of the osp(1|2) current algebra is analyzed. The four point conformal blocks of the theory are studied. The structure constants for the product of an arbitrary primary operator and a primary field that transforms according to the fundamental representation of osp(1|2) are explicitly calculated.Comment: 11 pages, phyzz

    Graded Parafermions

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    A graded generalization of the Z_k parafermionic current osp(1|2)/U(1) coset conformal field theory. The structure of the parafermionic highest-weight modules is analyzed and the dimensions of the fields of the theory are determined. A free field realization of the graded parafermionic system is obtained and the structure constants of the current algebra are found. Although the theory is not unitary, it presents good reducibility properties.Comment: 27 pages, LaTeX, 1 eps file. Typos correcte

    Fusion rules and singular vectors of the osp(1|2) current algebra

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    The fusion of Verma modules of the osp(1|2) current algebra is studied. In the framework of an isotopic formalism, the singular vector decoupling conditions are analyzed. The fusion rules corresponding to the admissible representations of the osp(1|2) algebra are determined. A relation between the characters of these last representations and those corresponding to the minimal superconformal models is found. A series of equations that relate the descendants of the highest weight vectors resulting from a fusion of Verma modules are obtained. Solving these equations the singular vectors of the theory can be determined.Comment: 63 pages, phyzz

    Structure constants for the osp(1|2) current algebra

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    We study the free field realization of the two-dimensional osp(1|2) current algebra. We consider the case in which the level of the affine osp(1|2) symmetry is a positive integer. Using the Coulomb gas technique we obtain integral representations for the conformal blocks of the model. In particular, from the behaviour of the four-point function, we extract the structure constants for the product of two arbitrary primary operators of the theory. From this result we derive the fusion rules of the osp(1|2) conformal field theory and we explore the connections between the osp(1|2) affine symmetry and the N=1 superconformal field theories.Comment: 64 pages, phyzzx, no figure

    K^+ -> pi^+pi^0e^+e^-: a novel short-distance probe

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    We study the decay K^+ -> pi^+ pi^0 e^+ e^-, currently under analysis by the NA62 Collaboration at CERN. In particular, we provide a detailed analysis of the Dalitz plot for the long-distance, gamma^*-mediated, contributions (Bremsstrahlung, direct emission and its interference). We also examine a set of asymmetries to isolate genuine short-distance effects. While we show that charge asymmetries are not required to test short distances, they provide the best environment for its detection. This constitutes by itself a strong motivation for NA62 to study K^- decays in the future. We therefore provide a detailed study of different charge asymmetries and the corresponding estimated signals. Whenever possible, we make contact with the related processes K^+ -> pi^+ pi^0 gamma and K_L -> pi^+ pi^- e^+ e^- and discuss the advantages of K^+ -> pi^+ pi^0 e^+ e^- over them.Comment: 25 pages, 6 figure

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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