461 research outputs found
THE TOOLS AND MONTE CARLO WORKING GROUP Summary Report from the Les Houches 2009 Workshop on TeV Colliders
This is the summary and introduction to the proceedings contributions for the
Les Houches 2009 "Tools and Monte Carlo" working group.Comment: 144 Pages. Workshop site
http://wwwlapp.in2p3.fr/conferences/LesHouches/Houches2009/ . Conveners were
Butterworth, Maltoni, Moortgat, Richardson, Schumann and Skand
Jet Substructure at the Tevatron and LHC: New results, new tools, new benchmarks
In this report we review recent theoretical progress and the latest
experimental results in jet substructure from the Tevatron and the LHC. We
review the status of and outlook for calculation and simulation tools for
studying jet substructure. Following up on the report of the Boost 2010
workshop, we present a new set of benchmark comparisons of substructure
techniques, focusing on the set of variables and grooming methods that are
collectively known as "top taggers". To facilitate further exploration, we have
attempted to collect, harmonise, and publish software implementations of these
techniques.Comment: 53 pages, 17 figures. L. Asquith, S. Rappoccio, C. K. Vermilion,
editors; v2: minor edits from journal revision
Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA
An investigation of the hadronic final state in diffractive and
non--diffractive deep--inelastic electron--proton scattering at HERA is
presented, where diffractive data are selected experimentally by demanding a
large gap in pseudo --rapidity around the proton remnant direction. The
transverse energy flow in the hadronic final state is evaluated using a set of
estimators which quantify topological properties. Using available Monte Carlo
QCD calculations, it is demonstrated that the final state in diffractive DIS
exhibits the features expected if the interaction is interpreted as the
scattering of an electron off a current quark with associated effects of
perturbative QCD. A model in which deep--inelastic diffraction is taken to be
the exchange of a pomeron with partonic structure is found to reproduce the
measurements well. Models for deep--inelastic scattering, in which a
sizeable diffractive contribution is present because of non--perturbative
effects in the production of the hadronic final state, reproduce the general
tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
Novel mutations in TLR genes cause hyporesponsiveness to Mycobacterium avium subsp. paratuberculosis infection
<p>Abstract</p> <p>Background</p> <p>Toll like receptors (TLR) play the central role in the recognition of pathogen associated molecular patterns (PAMPs). Mutations in the TLR1, TLR2 and TLR4 genes may change the ability to recognize PAMPs and cause altered responsiveness to the bacterial pathogens.</p> <p>Results</p> <p>The study presents association between TLR gene mutations and increased susceptibility to <it>Mycobacterium avium </it>subsp. <it>paratuberculosis </it>(MAP) infection. Novel mutations in TLR genes (TLR1- Ser150Gly and Val220Met; TLR2 â Phe670Leu) were statistically correlated with the hindrance in recognition of MAP legends. This correlation was confirmed subsequently by measuring the expression levels of cytokines (IL-4, IL-8, IL-10, IL-12 and IFN-Îł) in the mutant and wild type moDCs (mocyte derived dendritic cells) after challenge with MAP cell lysate or LPS. Further <it>in silico </it>analysis of the TLR1 and TLR4 ectodomains (ECD) revealed the polymorphic nature of the central ECD and irregularities in the central LRR (leucine rich repeat) motifs.</p> <p>Conclusion</p> <p>The most critical positions that may alter the pathogen recognition ability of TLR were: the 9<sup>th </sup>amino acid position in LRR motif (TLR1âLRR10) and 4<sup>th </sup>residue downstream to LRR domain (exta-LRR region of TLR4). The study describes novel mutations in the TLRs and presents their association with the MAP infection.</p
Cosmogenic background simulations for neutrinoless double beta decay with the DARWIN observatory at various underground sites
Xenon dual-phase time projections chambers (TPCs) have proven to be a successful technology in studying physical phenomena that require low-background conditions. With 40t of liquid xenon (LXe) in the TPC baseline design, DARWIN will have a high sensitivity for the detection of particle dark matter, neutrinoless double beta decay (0 Îœ ÎČ ÎČ), and axion-like particles (ALPs). Although cosmic muons are a source of background that cannot be entirely eliminated, they may be greatly diminished by placing the detector deep underground. In this study, we used Monte Carlo simulations to model the cosmogenic background expected for the DARWIN observatory at four underground laboratories: Laboratori Nazionali del Gran Sasso (LNGS), Sanford Underground Research Facility (SURF), Laboratoire Souterrain de Modane (LSM) and SNOLAB. We present here the results of simulations performed to determine the production rate of 137 Xe, the most crucial isotope in the search for 0 Îœ ÎČ ÎČ of 136 Xe. Additionally, we explore the contribution that other muon-induced spallation products, such as other unstable xenon isotopes and tritium, may have on the cosmogenic background
Cosmogenic background simulations for the DARWIN observatory at different underground locations
Xenon dual-phase time projections chambers (TPCs) have proven to be a
successful technology in studying physical phenomena that require
low-background conditions. With 40t of liquid xenon (LXe) in the TPC baseline
design, DARWIN will have a high sensitivity for the detection of particle dark
matter, neutrinoless double beta decay (), and axion-like
particles (ALPs). Although cosmic muons are a source of background that cannot
be entirely eliminated, they may be greatly diminished by placing the detector
deep underground. In this study, we used Monte Carlo simulations to model the
cosmogenic background expected for the DARWIN observatory at four underground
laboratories: Laboratori Nazionali del Gran Sasso (LNGS), Sanford Underground
Research Facility (SURF), Laboratoire Souterrain de Modane (LSM) and SNOLAB. We
determine the production rates of unstable xenon isotopes and tritium due to
muon-included neutron fluxes and muon-induced spallation. These are expected to
represent the dominant contributions to cosmogenic backgrounds and thus the
most relevant for site selection
DARWIN: towards the ultimate dark matter detector
DARk matter WImp search with liquid xenoN (DARWIN) will be an experiment forthe direct detection of dark matter using a multi-ton liquid xenon timeprojection chamber at its core. Its primary goal will be to explore theexperimentally accessible parameter space for Weakly Interacting MassiveParticles (WIMPs) in a wide mass-range, until neutrino interactions with thetarget become an irreducible background. The prompt scintillation light and thecharge signals induced by particle interactions in the xenon will be observedby VUV sensitive, ultra-low background photosensors. Besides its excellentsensitivity to WIMPs above a mass of 5 GeV/c2, such a detector with its largemass, low-energy threshold and ultra-low background level will also besensitive to other rare interactions. It will search for solar axions, galacticaxion-like particles and the neutrinoless double-beta decay of 136-Xe, as wellas measure the low-energy solar neutrino flux with <1% precision, observecoherent neutrino-nucleus interactions, and detect galactic supernovae. Wepresent the concept of the DARWIN detector and discuss its physics reach, themain sources of backgrounds and the ongoing detector design and R&D efforts
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