6,341 research outputs found
A superelement component dynamic synthesis method
A method is presented for coupling a broad class of component dynamic models in the manner of direct stiffness assembly. The method is implemented in a general matrix manipulation program
Search for nonpointing photons in the diphoton and ETmiss final state in root s=7 TeV proton-proton collisions using the ATLAS detector
A search has been performed for photons originating in the decay of a neutral long-lived particle, exploiting the capabilities of the ATLAS electromagnetic calorimeter to make precise measurements of the flight direction of photons, as well as the calorimeter's excellent time resolution. The search has been made in the diphoton plus missing transverse energy final state, using the full data sample of 4.8 fbā»Ā¹ of 7 TeV proton-proton collisions collected in 2011 with the ATLAS detector at the LHC. No excess is observed above the background expected from Standard Model processes. The results are used to set exclusion limits in the context of gauge mediated supersymmetry breaking models, with the lightest neutralino being the next-to-lightest supersymmetric particle and decaying with a lifetime in excess of 0.25 ns into a photon and a gravitino.G. Aad ... P. Jackson ... N. Soni ... M. J. White ... et al. (ATLAS Collaboration
On The Entanglement Entropy For Gauge Theories
We propose a definition for the entanglement entropy of a gauge theory on a
spatial lattice. Our definition applies to any subset of links in the lattice,
and is valid for both Abelian and Non-Abelian gauge theories. For
and theories, without matter, our definition agrees with
a particular case of the definition given by Casini, Huerta and Rosabal. We
also argue that in general, both for Abelian and Non-Abelian theories, our
definition agrees with the entanglement entropy calculated using a definition
of the replica trick. Our definition, however, does not agree with some
standard ways to measure entanglement, like the number of Bell pairs which can
be produced by entanglement distillation.Comment: 29 pages, 4 figures; section on Extended Lattice Construction revised
and some changes in referencing; some of the discussion of the replica trick
changed; section on SU(2) revised for clarit
Virtual RTCP: A Case Study of Monitoring and Repair for UDP-based IPTV Systems
IPTV systems have seen widespread deployment, but often lack robust mechanisms for monitoring the quality of experience. This makes it difficult for network operators to ensure that their services match the quality of traditional broadcast TV systems, leading to consumer dissatisfaction. We present a case study of virtual RTCP, a new framework for reception quality monitoring and reporting for UDP-encapsulated MPEG video delivered over IP multicast. We show that this allows incremental deployment of reporting infrastructure, coupled with effective retransmission-based packet loss repair
Precocious Diphoton Signals of the Little Radion at Hadron Colliders
In Little Randall-Sundrum models, the bulk couplings of the radion to
massless gauge fields can yield a greatly enhanced diphoton signal at hadron
colliders. We examine the implications of the Tevatron data for the Little
radion and also show that the 7 TeV run at the Large Hadron Collider will have
an impressive reach in this channel. The diphoton signal is crucial in the
search for a light radion, or the dual dilaton, and can potentially probe the
ultraviolet scale of the theory.Comment: 5 pages, 2 figures. Errors in the WW and ZZ branching fraction curves
in Fig.1 and the related numerical results in Fig.2 have been corrected. New
references have been added. Our main conclusions regarding the enhanced
diphoton signal of the Little radion remain qualitatively the same and
quantitatively similar to the previous result
The Radion as a Harbinger of Deca-TeV Physics
Precision data generally require the threshold for physics beyond the
Standard Model to be at the deca-TeV (10 TeV) scale or higher. This raises the
question of whether there are interesting deca-TeV models for which the LHC may
find direct clues. A possible scenario for such physics is a 5D warped model of
fermion masses and mixing, with Kaluza-Klein masses m_KK ~ 10 TeV, allowing it
to avoid tension with stringent constraints, especially from flavor data.
Discovery of a Standard-Model-like Higgs boson, for which there are some hints
at ~125 GeV at the LHC, would also require the KK masses to be at or above 10
TeV. These warped models generically predict the appearance of a much lighter
radion scalar. We find that, in viable warped models of flavor, a radion with a
mass of a few hundred GeV and an inverse coupling of order m_KK ~ 10 TeV could
typically be accessible to the LHC experiments -- with sqrt(s) = 14 TeV and 100
fb^-1 of data. The above statements can be applied, mutatis mutandis, to 4D
dual models, where conformal dynamics and a dilaton replace warping and the
radion, respectively. Detection of such a light and narrow scalar could thus
herald the proximity of a new physical threshold and motivate experiments that
would directly probe the deca-TeV mass scale.Comment: 18 pages, 5 figures; version published in Physical Review
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