18 research outputs found
MDT data quality assessment at the Calibration Centres for the ATLAS experiment at LHC
ATLAS is a large multipurpose detector, presently in the final phase of construction at the CERN Large Hadron Collider accelerator. In ATLAS the muon detection is performed by a huge magnetic spectrometer, built with the Monitored Drift Tube technology. It consists of more than 1,000 chambers and 350,000 drift tubes, which have to be controlled to a spatial accuracy better than 10 ÎĽm and an efficiency close to 100%. Therefore, the automated monitoring of the detector is an essential aspect of the operation of the spectrometer. The quality procedure collects data from online and offline sources and from the Calibration Stream at the Calibration Centres, situated in Ann Arbor (Michigan), MPI (Munich) and INFN Rome. The assessment at the Calibration Centres is performed using the DQHistogramAnalyzer utility of the ATHENA package. This application checks the histograms in an automated way and, after a further inspection with a human interface, reports results and summaries. The analysis results are stored in an Oracle Database using the COOL LCG library, through a C++ object-oriented interface. In this study a complete description of the entire chain, from the calibration stream up to the database storage is presented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85418/1/jpconf10_219_032062.pd
Multiple Interactions and the Structure of Beam Remnants
Recent experimental data have established some of the basic features of
multiple interactions in hadron-hadron collisions. The emphasis is therefore
now shifting, to one of exploring more detailed aspects. Starting from a brief
review of the current situation, a next-generation model is developed, wherein
a detailed account is given of correlated flavour, colour, longitudinal and
transverse momentum distributions, encompassing both the partons initiating
perturbative interactions and the partons left in the beam remnants. Some of
the main features are illustrated for the Tevatron and the LHC.Comment: 69pp, 33 figure
Constraints on Supersymmetry from LHC data on SUSY searches and Higgs bosons combined with cosmology and direct dark matter searches
The ATLAS and CMS experiments did not find evidence for Supersymmetry using
close to 5/fb of published LHC data at a center-of-mass energy of 7 TeV. We
combine these LHC data with data on B_s -> mu mu (LHCb experiment), the relic
density (WMAP and other cosmological data) and upper limits on the dark matter
scattering cross sections on nuclei (XENON100 data). The excluded regions in
the constrained Minimal Supersymmetric SM (CMSSM) lead to gluinos excluded
below 1270 GeV and dark matter candidates below 220 GeV for values of the
scalar masses (m_0) below 1500 GeV. For large m_0 values the limits of the
gluinos and the dark matter candidate are reduced to 970 GeV and 130 GeV,
respectively. If a Higgs mass of 125 GeV is imposed in the fit, the preferred
SUSY region is above this excluded region, but the size of the preferred region
is strongly dependent on the assumed theoretical error.Comment: 12 pages, 5 figures, Refs. updated, Published version in Eur. Phys.
J. C with updated references and minor corrections. arXiv admin note:
substantial text overlap with arXiv:1202.336
Updated Reach of the CERN LHC and Constraints from Relic Density, b->s gamma and a(mu) in the mSUGRA Model
{We present an updated assessment of the reach of the CERN LHC pp collider
for supersymmetric matter in the context of the minimal supergravity (mSUGRA)
model. In addition to previously examined channels, we also include signals
with an isolated photon or with a leptonically decaying Z boson. For an
integrated luminosity of 100 fb^{-1}, values of m_{1/2}\sim 1400 GeV can be
probed for small m_0, corresponding to a gluino mass of m_{\tg}\sim 3 TeV. For
large m_0, in the hyperbolic branch/focus point region, m_{1/2}\sim 700 GeV can
be probed, corresponding to m_{\tg}\sim 1800 GeV. We also map out parameter
space regions preferred by the measured values of the dark matter relic
density, the b\to s\gamma decay rate, and the muon anomalous magnetic moment
a_\mu, and discuss how SUSY might reveal itself in these regions. We find the
CERN LHC can probe the entire stau co-annihilation region and also most of the
heavy Higgs annihilation funnel allowed by WMAP data, except for some range of
large m_0 and m_{1/2} if \tan\beta \agt 50.Comment: 22 page latex file including 10 EPS figures; bug fix in relic density
code modifies figures in co-annihilation regio
Muon Spectrometer Phase-I Upgrade for the ATLAS Experiment: the New Small Wheel project
The instantaneous luminosity of the Large Hadron Collider at CERN will be increased by up to a factor of five to seven with respect to the design value. To maintain an excellent detection and background rejection capability in the forward region of the ATLAS detector, part of the muon detection system will be upgraded during LHC shutdown periods with the replacement of part of the present first station in the forward regions with the so-called New Small Wheels (NSWs). The NSWs will have a diameter of approximately 10 m and will be made of two detector technologies: Micromegas and small-strip Thin Gap Chambers (sTGC). The physics motivation for this significant upgrade to the ATLAS detector will be presented. The design choices made to address the physics needs will be discussed. Finally, the status of the production of the detector modules will be presented
New gas distribution system for the ATLAS RPCs
A new gas distribution system for the ATLAS RPCs aimed at equalizing the flow with respect to the average counting rate per gas volume. The system takes into account the expected luminosity foreseen in superLHC (sLHC) and the consequent increase of gas flow necessary for the proper operation
A new approach in simulating RPC and searching for the causes of large cluster size of RPC
The impact of intrinsic charm on the parton distribution functions
In this work, we present a new investigation about the impact of intrinsic
charm (IC) on the physical observables, in particular, on the heavy structure
function . Since IC distribution is dominant at large Bjorken variable
, normally, it is expected that it can be explored only at large . But,
by studying the correlation of the charm density in the proton with , we
are going to show that the IC component can also be effective at low . To
investigate further, we perform three QCD global analyses of parton
distribution functions (PDFs), by including the EMC data that are
recognized as clear evidence for existence of the intrinsic charm in the
proton, and also by considering the IC component. Although the fit of the EMC
data is extremely poor due to the data points with lower values, i.e. 0.05, but these analyses can give us new information about the impact of EMC
data and IC contribution on the behaviour of PDFs.Comment: I withdraw this paper since my supervisor require me to withdraw this
pape