2,454 research outputs found
SUSY Searches in All-Hadronic States with Large MET at the LHC
The CMS and ATLAS search strategy for SUSY in inclusive multijet plus high
missing transverse energy final states is reviewed. This canonical SUSY
signature may be a viable discovery channel for low mass SUSY in the early
phase of the LHC. Methods for Standard Model background estimates, MET studies
and filters for instrumental background are presented.Comment: Submitted for the SUSY07 proceedings, 4 pages, LaTeX, 13 eps figure
Q(2) dependence of nuclear transparency for exclusive rho(0) production
Exclusive coherent and incoherent electroproduction of the rho(0) meson from H-1 and N-14 targets has been studied at the HERMES experiment as a function of coherence length (l(c)), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (-Q(2)). The ratio of N-14 to H-1 cross sections per nucleon, called nuclear transparency, was found to increase (decrease) with increasing l(c) for coherent (incoherent) rho(0) electroproduction. For fixed l(c), a rise of nuclear transparency with Q(2) is observed for both coherent and incoherent rho(0) production, which is in agreement with theoretical calculations of color transparency
Species doubling and effective Lagrangians
Coupling gauge fields to the chiral currents from an effective Lagrangian for
pseudoscalar mesons naturally gives rise to a species doubling phenomenon
similar to that seen with fermionic fields in lattice gauge theory.Comment: 4 pages, uses espcrc.sty. Talk presented at LATTICE96(poster
Evidence for quark-hadron duality in the proton spin asymmetry A(1)
Spin-dependent lepton-nucleon scattering data have been used to investigate the validity of the concept of quark-hadron duality for the spin asymmetry A(1). Longitudinally polarized positrons were scattered off a longitudinally polarized hydrogen target for values of Q(2) between 1.2 and 12 GeV2 and values of W-2 between 1 and 4 GeV2. The average double-spin asymmetry in the nucleon resonance region is found to agree with that measured in deep-inelastic scattering at the same values of the Bjorken scaling variable x. This finding implies that the description of A(1) in terms of quark degrees of freedom is valid also in the nucleon resonance region for values of Q(2) above 1.6 GeV2
Exploring Advanced Detector Technologies for Muon Radiography Applications
Muon radiography often referred to as muography, is an imaging technique that
uses freely available cosmic-ray muons to study the interior structure of
natural or man-made large-scale objects. The amount of multidisciplinary
applications of this technique keeps increasing over time and a variety of
basic detector types have already been used in the construction of muon
telescopes. Here, we are investigating the use of advanced gaseous detectors
for muography. As our basic solution, given its robustness and ease of
operation in remote, outdoor environments, a scintillator-based muon telescope
with silicon photomultiplier readout is being developed. To enhance the
telescope performance, we are proposing the use of Multi-gap Resistive Plate
Chambers (mRPCs) and Thick Gas Electron Multipliers (THGEMs). While the former
offer superior time resolution which could be beneficial for detector
background rejection, the latter detector type offers excellent spatial
resolution, can be manufactured at low cost and operated with a simple gas
mixture. Currently, prototype detector planes for each of these proposed types
are being designed and constructed, and initial performance tests are in
progress. In parallel, a Geant4- based muon telescope simulation is being
developed, which will enable us to e.g. optimize our telescope geometry and
study the use of superior time resolution for background rejection. The design
and status of the three detector prototype planes and the muon telescope, along
with the initial results of their performance tests and of the Geant4
simulation studies are reported
Lattice Formulation of the Standard Model
Combining the Kaplan surface mode approach for chiral fermions with added
terms motivated by Eichten and Preskill suggests the possibility for a lattice
regularization of the standard model which is finite, exactly gauge invariant,
and only has physically desired states in its low energy spectrum. The
conjectured scheme manifestly requires anomaly cancelation and explicitly
contains baryon and lepton number violating terms.Comment: 11 pages, late
Portable Resistive Plate Chambers for Muography in confined environments
Muography (or muon radiography) is an imaging technique that relies on the
use of cosmogenic muons as a free and safe radiation source. It can be applied
in various fields such as archaeology, civil engineering, geology, nuclear
reactor monitoring, nuclear waste characterization, underground surveys, etc.
In such applications, sometimes deploying muon detectors is challenging due to
logistics, e.g. in a narrow underground tunnel or mine. Therefore, we are
developing muon detectors whose design goals include portability, robustness,
autonomy, versatility, and safety. Our portable muon detectors (or
``muoscopes'') are based on Resistive Plate Chambers (RPC), planar detectors
that use ionization in a thin gas gap to detect cosmic muons. Prototype RPCs of
active area and were built in our
laboratories at Louvain-la-Neuve (UCLouvain) and Ghent (UGent) to test and
compare various design options. Benefiting from the experience gained in
building and operating these prototypes, we are proceeding towards the
development of improved prototypes with more advanced technical layout and
readiness. In this paper we provide the status of our performance studies,
including the cross-validation of the two types of prototypes in a joint data
taking, and an outline of the direction ahead
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