218 research outputs found
Chiral-Yang-Mills theory, non commutative differential geometry, and the need for a Lie super-algebra
In Yang-Mills theory, the charges of the left and right massless Fermions are
independent of each other. We propose a new paradigm where we remove this
freedom and densify the algebraic structure of Yang-Mills theory by integrating
the scalar Higgs field into a new gauge-chiral 1-form which connects Fermions
of opposite chiralities. Using the Bianchi identity, we prove that the
corresponding covariant differential is associative if and only if we gauge a
Lie-Kac super-algebra. In this model, spontaneous symmetry breakdown naturally
occurs along an odd generator of the super-algebra and induces a representation
of the Connes-Lott non commutative differential geometry of the 2-point finite
space.Comment: 17 pages, no figur
Indecomposable doubling for representations of the type I Lie superalgebras sl(m/n) and osp(2/2n)
We establish that for the type I Lie superalgebras and ,
each Kac module admits a 1 parameter family of indecomposable double
extensions. The result follows from the explicit evaluation of the Lie
superalgebra cohomology valued in the tensor product of the module and its
dual.Comment: 14 pages, LaTeX. Minor corrections and clarifications added. Citation
adde
Mass generation for non-Abelian antisymmetric tensor fields in a three-dimensional space-time
Starting from a recently proposed Abelian topological model in (2+1)
dimensions, which involve the Kalb-Ramond two form field, we study a
non-Abelian generalization of the model. An obstruction for generalization is
detected. However we show that the goal is achieved if we introduce a vectorial
auxiliary field. Consequently, a model is proposed, exhibiting a non-Abelian
topological mass generation mechanism in D=3, that provides mass for the
Kalb-Ramond field. The covariant quantization of this model requires ghosts for
ghosts. Therefore in order to quantize the theory we construct a complete set
of BRST and anti-BRST equations using the horizontality condition.Comment: 8 pages. To appear in Physical Review
Supersymmetrization of horizontality condition: nilpotent symmetries for a free spinning relativistic particle
We derive the off-shell nilpotent and absolutely anticommuting
Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetry transformations for a
supersymmetric system of a free spinning relativistic particle within the
framework of superfield approach to BRST formalism. A novel feature of our
present investigation is the consistent and clear supersymmetric modification
of the celebrated horizontality condition for the precise determination of the
proper (anti-)BRST symmetry transformations for all the bosonic and fermionic
dynamical variables of our theory which is considered on a (1, 2)-dimensional
supermanifold parameterized by an even (bosonic) variable (\tau) and a pair of
odd (fermionic) variables \theta and \bar\theta (with \theta^2 = \bar\theta^2 =
0,\; \theta \bar\theta + \bar\theta \theta = 0) of the Grassmann algebra. One
of the most important features of our present investigation is the derivation
of (anti-)BRST invariant Curci-Ferrari type restriction which turns out to be
responsible for the absolute anticommutativity of the (anti-)BRST symmetry
transformations and existence of the coupled (but equivalent) Lagrangians for
the present theory of a supersymmetric system.Comment: LaTeX file, 24 pages, version to appear in EPJ
Construction of matryoshka nested indecomposable N-replications of Kac-modules of quasi-reductive Lie superalgebras, including the sl(m/n) and osp(2/2n) series
We construct a new class of finite dimensional indecomposable representations
of simple superalgebras which may explain, in a natural way, the existence of
the heavier elementary particles. In type I Lie superalgebras sl(m/n) and
osp(2/2n), one of the Dynkin weights labeling the finite dimensional
irreducible representations is continuous. Taking the derivative, we show how
to construct indecomposable representations recursively embedding N copies of
the original irreducible representation, coupled by generalized Cabibbo angles,
as observed among the three generations of leptons and quarks of the standard
model. The construction is then generalized in the appendix to quasi-reductive
Lie superalgebras.Comment: Revised version 2 with minor modifications. On the suggestion of the
referee, we show that the construction does not apply to the psl(n/n)
superalgebras. 15 pages, 32 references Revised version 3 no modification
except reformatting the bibliography and adding do
Weighted pooling—practical and cost-effective techniques for pooled high-throughput sequencing
Motivation: Despite the rapid decline in sequencing costs, sequencing large cohorts of individuals is still prohibitively expensive. Recently, several sophisticated pooling designs were suggested that can identify carriers of rare alleles in large cohorts with a significantly smaller number of pools, thus dramatically reducing the cost of such large-scale sequencing projects. These approaches use combinatorial pooling designs where each individual is either present or absent from a pool. One can then infer the number of carriers in a pool, and by combining information across pools, reconstruct the identity of the carriers
Distribution of satellite galaxies in high redshift groups
We use galaxy groups at redshifts between 0.4 and 1.0 selected from the Great
Observatories Origins Deep Survey (GOODS) to study the color-morphological
properties of satellite galaxies, and investigate possible alignment between
the distribution of the satellites and the orientation of their central galaxy.
We confirm the bimodal color and morphological type distribution for satellite
galaxies at this redshift range: the red and blue classes corresponds to the
early and late morphological types respectively, and the early-type satellites
are on average brighter than the late-type ones. Furthermore, there is a {\it
morphological conformity} between the central and satellite galaxies: the
fraction of early-type satellites in groups with an early-type central is
higher than those with a late-type central galaxy. This effect is stronger at
smaller separations from the central galaxy. We find a marginally significant
signal of alignment between the major axis of the early-type central galaxy and
its satellite system, while for the late-type centrals no significant alignment
signal is found. We discuss the alignment signal in the context of shape
evolution of groups.Comment: 7 pages, 7 figures, accepted by Ap
Superfield Approach to (Non-)local Symmetries for One-Form Abelian Gauge Theory
We exploit the geometrical superfield formalism to derive the local,
covariant and continuous Becchi-Rouet-Stora-Tyutin (BRST) symmetry
transformations and the non-local, non-covariant and continuous dual-BRST
symmetry transformations for the free Abelian one-form gauge theory in four -dimensions (4D) of spacetime. Our discussion is carried out in the
framework of BRST invariant Lagrangian density for the above 4D theory in the
Feynman gauge. The geometrical origin and interpretation for the (dual-)BRST
charges (and the transformations they generate) are provided in the language of
translations of some superfields along the Grassmannian directions of the six
(-dimensional supermanifold parametrized by the four spacetime and two
Grassmannian variables.Comment: LaTeX file, 23 page
Superfield approach to symmetry invariance in QED with complex scalar fields
We show that the Grassmannian independence of the super Lagrangian density,
expressed in terms of the superfields defined on a (4, 2)-dimensional
supermanifold, is a clear-cut proof for the Becchi-Rouet-Stora-Tyutin (BRST)
and anti-BRST invariance of the corresoponding four (3 + 1)-dimensional (4D)
Lagrangian density that describes the interaction between the U(1) gauge field
and the charged complex scalar fields. The above 4D field theoretical model is
considered on a (4, 2)-dimensional supermanifold parametrized by the ordinary
four spacetime variables x^\mu (with \mu = 0, 1, 2, 3) and a pair of
Grassmannian variables \theta and \bar\theta (with \theta^2 = \bar\theta^2 = 0,
\theta \bar\theta + \bar\theta \theta = 0). Geometrically, the (anti-)BRST
invariance is encoded in the translation of the super Lagrangian density along
the Grassmannian directions of the above supermanifold such that the outcome of
this shift operation is zero.Comment: LaTeX file, 14 pages, minor changes in the title and text, version to
appear in ``Pramana - Journal of Physics'
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