143 research outputs found
Recommended from our members
Search for WW and WZ production in lepton, neutrino plus jets final states at CDF Run II and Silicon module production and detector control system for the ATLAS SemiConductor Tracker
In the first part of this work, we present a search for WW and WZ production in charged lepton, neutrino plus jets final states produced in p{bar p} collisions with {radical}s = 1.96 TeV at the Fermilab Tevatron, using 1.2 fb{sup -1} of data accumulated with the CDF II detector. This channel is yet to be observed in hadron colliders due to the large singleWplus jets background. However, this decay mode has a much larger branching fraction than the cleaner fully leptonic mode making it more sensitive to anomalous triple gauge couplings that manifest themselves at higher transverse W momentum. Because the final state is topologically similar to associated production of a Higgs boson with a W, the techniques developed in this analysis are also applicable in that search. An Artificial Neural Network has been used for the event selection optimization. The theoretical prediction for the cross section is {sigma}{sub WW/WZ}{sup theory} x Br(W {yields} {ell}{nu}; W/Z {yields} jj) = 2.09 {+-} 0.14 pb. They measured N{sub Signal} = 410 {+-} 212(stat) {+-} 102(sys) signal events that correspond to a cross section {sigma}{sub WW/WZ} x Br(W {yields} {ell}{nu}; W/Z {yields} jj) = 1.47 {+-} 0.77(stat) {+-} 0.38(sys) pb. The 95% CL upper limit to the cross section is estimated to be {sigma} x Br(W {yields} {ell}{nu}; W/Z {yields} jj) < 2.88 pb. The second part of the present work is technical and concerns the ATLAS SemiConductor Tracker (SCT) assembly phase. Although technical, the work in the SCT assembly phase is of prime importance for the good performance of the detector during data taking. The production at the University of Geneva of approximately one third of the silicon microstrip end-cap modules is presented. This collaborative effort of the university of Geneva group that lasted two years, resulted in 655 produced modules, 97% of which were good modules, constructed within the mechanical and electrical specifications and delivered in the SCT collaboration for assembly on the end-cap disks. The SCT end-caps and barrels consist of 4088 silicon modules, with a total of 6.3 million readout channels. The coherent and safe operation of the SCT during commissioning and subsequent operation is the essential task of the Detector Control System (DCS). The main building blocks of the DCS are the cooling system, the power supplies and the environmental system. The DCS has been initially developed for the SCT assembly phase and this system is described in the present work. Particular emphasis is given in the environmental hardware and software components, that were my major contributions. Results from the DCS testing during the assembly phase are also reported
Recommended from our members
Diboson physics at CDF
This article presents the most recent results of the diboson production properties, using up to {integral} Ldt = 1.9 fb{sup -1} of data taken with the CDF Run II detector, at Tevatron. We summarize measurements of the W{gamma}, Z{gamma}, WW, WZ and ZZ production cross sections in leptonic channels. A search for the combined WW and WZ production in lepton-neutrino plus dijet final states is also presented
Recommended from our members
Search for new physics in dilepton and diphoton final states at CDF
The CDF detector has accumulated a large data sample of p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron. In this report we present the results of searches for physics beyond the Standard Model using final states of 2 leptons or 2 photons using 190 pb{sup -1} to 448 pb{sup -1} of data. No deviation from the predictions of Standard Model was observed. The non-observation was used to derive cross section limits on contributions to these final states from possible new physics processes. For many specific new physics models, such as Z', Randall-Sundrum Graviton, Large Extra Dimensions and SUSY, these cross section limits can be used to place strong constraints on their parameters
A High Luminosity e+e- Collider to study the Higgs Boson
A strong candidate for the Standard Model Scalar boson, H(126), has been
discovered by the Large Hadron Collider (LHC) experiments. In order to study
this fundamental particle with unprecedented precision, and to perform
precision tests of the closure of the Standard Model, we investigate the
possibilities offered by An e+e- storage ring collider. We use a design
inspired by the B-factories, taking into account the performance achieved at
LEP2, and imposing a synchrotron radiation power limit of 100 MW. At the most
relevant centre-of-mass energy of 240 GeV, near-constant luminosities of 10^34
cm^{-2}s^{-1} are possible in up to four collision points for a ring of 27km
circumference. The achievable luminosity increases with the bending radius, and
for 80km circumference, a luminosity of 5 10^34 cm^{-2}s^{-1} in four collision
points appears feasible. Beamstrahlung becomes relevant at these high
luminosities, leading to a design requirement of large momentum acceptance both
in the accelerating system and in the optics. The larger machine could reach
the top quark threshold, would yield luminosities per interaction point of
10^36 cm^{-2}s^{-1} at the Z pole (91 GeV) and 2 10^35 cm^{-2}s^{-1} at the W
pair production threshold (80 GeV per beam). The energy spread is reduced in
the larger ring with respect to what is was at LEP, giving confidence that beam
polarization for energy calibration purposes should be available up to the W
pair threshold. The capabilities in term of physics performance are outlined.Comment: Submitted to the European Strategy Preparatory Group 01-04-2013 new
version as re-submitted to PRSTA
Beam Condition Monitoring with Diamonds at CDF
This report talks Beam Condition Monitoring with Diamonds at CD
Recommended from our members
Tevatron-for-LHC Report of the QCD Working Group
The experiments at Run 2 of the Tevatron have each accumulated over 1 fb{sup -1} of high-transverse momentum data. Such a dataset allows for the first precision (i.e. comparisons between theory and experiment at the few percent level) tests of QCD at a hadron collider. While the Large Hadron Collider has been designed as a discovery machine, basic QCD analyses will still need to be performed to understand the working environment. The Tevatron-for-LHC workshop was conceived as a communication link to pass on the expertise of the Tevatron and to test new analysis ideas coming from the LHC community. The TeV4LHC QCD Working Group focused on important aspects of QCD at hadron colliders: jet definitions, extraction and use of Parton Distribution Functions, the underlying event, Monte Carlo tunes, and diffractive physics. This report summarizes some of the results achieved during this workshop
COLLIMATION OPTIMISATION IN THE BEAM DELIVERY SYSTEM OF THE INTERNATIONAL LINEAR COLLIDER*
Abstract The collimation systems of the International Linear Collider (ILC) Beam Delivery System (BDS) must perform efficient removal of halo particles which lie outside the acceptable ranges of energy and spatial spread. An optimisation strategy based on earlier work is applied to the latest version of the BDS lattice. The resulting improvement in collimation performance is studied by halo tracking simulations, and the luminosity performance of the optimised lattice is also examined
- …