88 research outputs found
The 1953 Cosmic Ray Conference at Bagneres de Bigorre
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
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
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
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
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
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
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
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
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
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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