2,531 research outputs found
An 3d-3d Correspondence
M5-branes on an associative three-cycle in a -holonomy manifold
give rise to a 3d supersymmetric gauge theory,
. We propose an 3d-3d correspondence,
based on two observables of these theories: the Witten index and the
-partition function. The Witten index of a 3d theory
is shown to be computed in terms of the partition
function of a topological field theory, a super-BF-model coupled to a spinorial
hypermultiplet (BFH), on . The BFH-model localizes on solutions to a
generalized set of 3d Seiberg-Witten equations on . Evidence to support
this correspondence is provided in the abelian case, as well as in terms of a
direct derivation of the topological field theory by twisted dimensional
reduction of the 6d theory. We also consider a correspondence for the
-partition function of the theories, by
determining the dimensional reduction of the M5-brane theory on . The
resulting topological theory is Chern-Simons-Dirac theory, for a gauge field
and a twisted harmonic spinor on , whose equations of motion are the
generalized 3d Seiberg-Witten equations. For generic -manifolds the theory
reduces to real Chern-Simons theory, in which case we conjecture that the
-partition function of is given by the
Witten-Reshetikhin-Turaev invariant of .Comment: 63 pages, 4 figures; v2: JHEP versio
M5-branes on S^2 x M_4: Nahm's Equations and 4d Topological Sigma-models
We study the 6d N=(0,2) superconformal field theory, which describes multiple
M5-branes, on the product space S^2 x M_4, and suggest a correspondence between
a 2d N=(0,2) half-twisted gauge theory on S^2 and a topological sigma-model on
the four-manifold M_4. To set up this correspondence, we determine in this
paper the dimensional reduction of the 6d N=(0,2) theory on a two-sphere and
derive that the four-dimensional theory is a sigma-model into the moduli space
of solutions to Nahm's equations, or equivalently the moduli space of
k-centered SU(2) monopoles, where k is the number of M5-branes. We proceed in
three steps: we reduce the 6d abelian theory to a 5d Super-Yang-Mills theory on
I x M_4, with I an interval, then non-abelianize the 5d theory and finally
reduce this to 4d. In the special case, when M_4 is a Hyper-Kahler manifold, we
show that the dimensional reduction gives rise to a topological sigma-model
based on tri-holomorphic maps. Deriving the theory on a general M_4 requires
knowledge of the metric of the target space. For k=2 the target space is the
Atiyah-Hitchin manifold and we twist the theory to obtain a topological
sigma-model, which has both scalar fields and self-dual two-forms.Comment: 78 pages, 2 figure
F-theory and AdS_3/CFT_2
We construct supersymmetric AdS_3 solutions in F-theory, that is Type IIB
supergravity with varying axio-dilaton, which are holographically dual to 2d
N=(0,4) superconformal field theories with small superconformal algebra. In
F-theory these arise from D3-branes wrapped on curves in the base of an
elliptically fibered Calabi-Yau threefold Y_3 and correspond to strings in the
6d N=(1,0) theory obtained from F-theory on Y_3. The non-trivial fibration over
the wrapped curves implies a varying coupling of the N=4 Super-Yang-Mills
theory on the D3-branes. We compute the holographic central charges and show
that these agree with the field theory and with the anomalies of self-dual
strings in 6d. We complement our analysis with a discussion of the dual
M-theory solutions and a comparison of the central charges.Comment: 83 pages, v2: references added, typos correcte
Electron diffusion by magnetosonic waves in the Earthβs radiation belts
We conduct a global survey of magnetosonic waves and compute the associated bounce and drift averaged diffusion coefficients, taking into account co-located measurements of fpe/fce, to assess the role of magnetosonic waves in radiation belt dynamics. The average magnetosonic wave intensities increase with increasing geomagnetic activity and decreasing relative frequency with the majority of the wave power in the range fcp < f < 0.3fLHR during active conditions. In the region 4.0 β€ L* β€ 5.0, the bounce and drift averaged energy diffusion rates due to magnetosonic waves never exceed those due to whistler mode chorus, suggesting that whistler mode chorus is the dominant mode for electron energisation to relativistic energies in this region. Further in, in the region 2.0 β€ L* β€ 3.5, the bounce and drift averaged pitch angle diffusion rates due to magnetosonic waves can exceed those due to plasmaspheric hiss and very low frequency (VLF) transmitters over energy-dependent ranges of intermediate pitch angles. We compute electron lifetimes by solving the 1D pitch angle diffusion equation including the effects of plasmaspheric hiss, VLF transmitters and magnetosonic waves. We find that magnetosonic waves can have a significant effect on electron loss timescales in the slot region reducing the loss timescales during active times from 5.6 to 1.5 days for 500 keV electrons at L* = 2.5 and from 140.4 days to 35.7 days for 1 MeV electrons at L* = 2.0
Can the nearly conformal sextet gauge model hide the Higgs impostor?
New results are reported from large scale lattice simulations of a frequently
discussed strongly interacting gauge theory with a fermion flavor doublet in
the two-index symmetric (sextet) representation of the SU(3) color gauge group.
We find that the chiral condensate and the mass spectrum of the sextet model
are consistent with chiral symmetry breaking in the limit of vanishing fermion
mass. In contrast, sextet fermion mass deformations of spectral properties are
not consistent with leading conformal scaling behavior near the critical
surface of a conformal theory. A recent paper could not resolve the conformal
fixed point of the gauge coupling from the slowly walking scenario of a very
small nearly vanishing \beta-function (DeGrand:2012yq). It is argued that
overall consistency with our new results is resolved if the sextet model is
close to the conformal window, staying outside with a very small non-vanishing
\beta-function. The model would exhibit then the simplest composite Higgs
mechanism leaving open the possibility of a light scalar state with quantum
numbers of the Higgs impostor. It would emerge as the pseudo-Goldstone dilaton
state from spontaneous symmetry breaking of scale invariance. We will argue
that even without association with the dilaton, the scalar Higgs-like state can
be light very close to the conformal window. A new Higgs project of sextet
lattice simulations is outlined to resolve these important questions.Comment: 10 pages, 8 figure
A multi-targeted approach to suppress tumor-promoting inflammation
Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-ΞΊB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes
Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV
The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of βs = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pTβ₯20 GeV and pseudorapidities {pipe}Ξ·{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}Ξ·{pipe}<0. 8) for jets with 60β€pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2β€{pipe}Ξ·{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. Β© 2013 CERN for the benefit of the ATLAS collaboration
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