160 research outputs found
Transverse-momentum resummation for the signal-background interference in the H →γγ channel at the LHC
We present an upgraded calculation of the effects of resonance-continuum interference for the Higgs boson decaying to two photons at the Large Hadron Collider, at next-to-leading order in the strong coupling αS, O(αS3), and including transverse-momentum (qT) resummation at next-to-leading logarithmic accuracy. We study the importance of the interference contribution in different transverse-momentum regions, with a particular focus on the low-qT region qT2 Q2 (with Q2 being the invariant diphoton mass) where resummation becomes essential for a reliable calculation
Seiberg-Witten-type Maps for Currents and Energy-Momentum Tensors in Noncommutative Gauge Theories
We derive maps relating the currents and energy-momentum tensors in
noncommutative (NC) gauge theories with their commutative equivalents. Some
uses of these maps are discussed. Especially, in NC electrodynamics, we obtain
a generalization of the Lorentz force law. Also, the same map for anomalous
currents relates the Adler-Bell-Jackiw type NC covariant anomaly with the
standard commutative-theory anomaly. For the particular case of two dimensions,
we discuss the implications of these maps for the Sugawara-type energy-momentum
tensor.Comment: 14 pages, JHEP styl
Towards an explicit expression of the Seiberg-Witten map at all orders
The Seiberg-Witten map links noncommutative gauge theories to ordinary gauge
theories, and allows to express the noncommutative variables in terms of the
commutative ones. Its explicit form can be found order by order in the
noncommutative parameter theta and the gauge potential A by the requirement
that gauge orbits are mapped on gauge orbits. This of course leaves
ambiguities, corresponding to gauge transformations, and there is an infinity
of solutions. Is there one better, clearer than the others ? In the abelian
case, we were able to find a solution, linked by a gauge transformation to
already known formulas, which has the property of admitting a recursive
formulation, uncovering some pattern in the map. In the special case of a pure
gauge, both abelian and non-abelian, these expressions can be summed up, and
the transformation is expressed using the parametrisation in terms of the gauge
group.Comment: 17 pages. Latex, 1 figure. v2: minor changes, published versio
A sigma model field theoretic realization of Hitchin's generalized complex geometry
We present a sigma model field theoretic realization of Hitchin's generalized
complex geometry, which recently has been shown to be relevant in
compactifications of superstring theory with fluxes. Hitchin sigma model is
closely related to the well known Poisson sigma model, of which it has the same
field content. The construction shows a remarkable correspondence between the
(twisted) integrability conditions of generalized almost complex structures and
the restrictions on target space geometry implied by the Batalin--Vilkovisky
classical master equation. Further, the (twisted) classical Batalin--Vilkovisky
cohomology is related non trivially to a generalized Dolbeault cohomology.Comment: 28 pages, Plain TeX, no figures, requires AMS font files AMSSYM.DEF
and amssym.tex. Typos in eq. 6.19 and some spelling correcte
Emergent Gravity from Noncommutative Spacetime
We showed before that self-dual electromagnetism in noncommutative (NC)
spacetime is equivalent to self-dual Einstein gravity. This result implies a
striking picture about gravity: Gravity can emerge from electromagnetism in NC
spacetime. Gravity is then a collective phenomenon emerging from gauge fields
living in fuzzy spacetime. We elucidate in some detail why electromagnetism in
NC spacetime should be a theory of gravity. In particular, we show that NC
electromagnetism is realized through the Darboux theorem as a diffeomorphism
symmetry G which is spontaneously broken to symplectomorphism H due to a
background symplectic two-form , giving rise to
NC spacetime. This leads to a natural speculation that the emergent gravity
from NC electromagnetism corresponds to a nonlinear realization G/H of the
diffeomorphism group, more generally its NC deformation. We also find some
evidences that the emergent gravity contains the structure of generalized
complex geometry and NC gravity. To illuminate the emergent gravity, we
illustrate how self-dual NC electromagnetism nicely fits with the twistor space
describing curved self-dual spacetime. We also discuss derivative corrections
of Seiberg-Witten map which give rise to higher order gravity.Comment: 50 pages; Cosmetic revision and updated reference
Generalized Kaehler Potentials from Supergravity
We consider supersymmetric N=2 solutions with non-vanishing NS three-form.
Building on worldsheet results, we reduce the problem to a single generalized
Monge-Ampere equation on the generalized Kaehler potential K recently
interpreted geometrically by Lindstrom, Rocek, Von Unge and Zabzine. One input
in the procedure is a holomorphic function w that can be thought of as the
effective superpotential for a D3 brane probe. The procedure is hence likely to
be useful for finding gravity duals to field theories with non-vanishing
abelian superpotential, such as Leigh-Strassler theories. We indeed show that a
purely NS precursor of the Lunin-Maldacena dual to the beta-deformed N=4
super-Yang-Mills falls in our class.Comment: "38 pages. v3: improved exposition and minor mistakes corrected in
sec. 4
The Hitchin functionals and the topological B-model at one loop
The quantization in quadratic order of the Hitchin functional, which defines
by critical points a Calabi-Yau structure on a six-dimensional manifold, is
performed. The conjectured relation between the topological B-model and the
Hitchin functional is studied at one loop. It is found that the genus one free
energy of the topological B-model disagrees with the one-loop free energy of
the minimal Hitchin functional. However, the topological B-model does agree at
one-loop order with the extended Hitchin functional, which also defines by
critical points a generalized Calabi-Yau structure. The dependence of the
one-loop result on a background metric is studied, and a gravitational anomaly
is found for both the B-model and the extended Hitchin model. The anomaly
reduces to a volume-dependent factor if one computes for only Ricci-flat Kahler
metrics.Comment: 33 pages, LaTe
FHIT gene therapy prevents tumor development in Fhit-deficient mice
The tumor suppressor gene FHIT spans a common fragile site and is highly susceptible to environmental carcinogens. FHIT inactivation and loss of expression is found in a large fraction of premaligant and malignant lesions. In this study, we were able to inhibit tumor development by oral gene transfer, using adenoviral or adenoassociated viral vectors expressing the human FHIT gene, in heterozygous Fhit+/- knockout mice, that are prone to tumor development after carcinogen exposure. We therefore suggest that FHIT gene therapy could be a novel clinical approach not only in treatment of early stages of cancer, but also in prevention of human cancer
Supersymmetric AdS_5 solutions of M-theory
We analyse the most general supersymmetric solutions of D=11 supergravity
consisting of a warped product of five-dimensional anti-de-Sitter space with a
six-dimensional Riemannian space M_6, with four-form flux on M_6. We show that
M_6 is partly specified by a one-parameter family of four-dimensional Kahler
metrics. We find a large family of new explicit regular solutions where M_6 is
a compact, complex manifold which is topologically a two-sphere bundle over a
four-dimensional base, where the latter is either (i) Kahler-Einstein with
positive curvature, or (ii) a product of two constant-curvature Riemann
surfaces. After dimensional reduction and T-duality, some solutions in the
second class are related to a new family of Sasaki-Einstein spaces which
includes T^{1,1}/Z_2. Our general analysis also covers warped products of
five-dimensional Minkowski space with a six-dimensional Riemannian space.Comment: 40 pages. v2: minor changes, eqs. (2.22) and (D.12) correcte
A primary cutaneous adenoid-cystic carcinoma in a young woman. Differential diagnosis and clinical implications
Primary cutaneous adenoid-cystic carcinoma (PCACC) is a rare slow-growing neoplasm of disputed histogenesis characterized by a cribriform pattern at histology and local aggressive behaviour. Up to date about 60 cases of PCACC have been reported in the literature. This tumour is most common in the scalp, affects middle-aged and older individuals (mean age 59) and has predilection for women. We describe an unexpected case of PCACC in a 32-years-old woman referred to our clinic for a subcutaneous nodule in the scalp showing a slow growth and indolent course. The differential diagnosis and the clinical management of this PCACC patient, successfully treated with a wide local excision, are presented and discussed
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