2,891 research outputs found
Single Top production at CMS
A first measurement of the cross section of single top quark production in
the t channel in pp collision at sqrt(s)=7 TeV is presented. The measurement is
performed on a data sample corresponding to an integrated luminosity of 35.9
pb^-1 recorded at the LHC with the CMS detector. Leptonic decay channels with
an electron or a muon in the final state are considered. After a selection
optimized for the t-channel mode, two different and complementary analyses have
been performed. Both analyses confirm the Tevatron's observation of single top,
and their combination measures a cross section of sigma = 83.6 +/-
29.8(stat.+syst.) +/- 3.3 (lumi.) pb, which is consistent with the Standard
Model prediction.Comment: 7 pages, 3 figures, Proceedings of the DPF-2011 Conference,
Providence, RI, August 8-13, 201
The ATLAS and CMS Detectors and Triggers for B physics
The ATLAS and CMS detectors are the two general purpose experiments which will be operated at the LHC, and these have been designed to explore the full range of physics that can be accessed at LHC energies. With the large b production cross section and high luminosity foreseen a substantial number of b-flavoured hadrons can be expected to be recorded. For both experiments, a brief description of the most relevant detectors, the trigger systems and the trigger strategy envisaged for B physics is presented
B physics at CMS
The Compact Muon Solenoid (CMS) is a multi-purpose detector which will be operated at the Large Hadron Collider (LHC) at CERN. The capabilities of the CMS experiment in the field of physics has been studied in several benchmark processes which are representative of exclusive physics analysis. They allow to study the capability of CMS to identify, select and reconstruct the decay of the -flavoured hadrons, which presents a significant challenge due to their relatively low momentum and high background
Strategies for btagging calibration using collider data at CMS
The CMS Collaboration is studying several algorithms to identify jets coming from the hadronization of bottom quarks (b-jets) which are present in a wide range of physics processes of interests such as in the decay of top quarks, Higgs bosons and several non-Standard Model particles. All of these b-tagging algorithms rely upon the reconstruction of lower level objects like tracks, vertices, and jets, which might make it difficult for the Monte Carlo simulation to exactly reproduce the performance observed in data. Reliable methods to measure performance of these algorithms directly from collider data have been developed. The CMS b-tagging group is working on several strategies which should yield reliable results already with of integrated luminosity
Lorentz angle calibration for the barrel pixel detector
A method to measure the Lorentz angle in the barrel pixel detector of CMS is presented. This measurement from CMS data will be necessary during operation since the electric field in the sensors will change with increasing irradiation. The approach described in this note uses well measured muon tracks to determine the drift of the electrons in the pixel sensors. From an analysis of simulated data an accuracy of 2% on tau_L can be achieved from just 1000 muon tracks. This corresponds to a systematic shift in the hit reconstruction of less than 1.5 \mu m which will decrease with increasing integrated luminosity
Proteção de camundongos atímicos BALB/c (Nu/Nu) contra Plasmodium berghei por esplenócitos oriundos de camundongos normais BALB/c (Nu/+)
Camundongos atímicos BALB/c (Nu/Nu) sucumbem entre 7-13 dias após a inoculação (DAI) da cepa NK65 de Plasmodium berghei. Todavia, seus singenêicos heterozigotos (Nu/+) morrem em 7-8 DAI. Camundongos nude (Nu/Nu) reconstituídos com 2xl0(7) esplenócitos de camundongos heterozigotos singenêicos normais não infectados (Nu/+) 20 dias antes da inoculação a (DBI) do parasita, sucumbem 2 dias antes que os animais controles. Camundongos nude reconstituídos 10 ou 2 DBI, vivem 2-4 dias a mais que os animais controles e alguns deles sobrevivem. Esses achados indicam que a cepa NK65 de P. berghei induz, no mínimo, dois imunofenômenos dependentes de linfócitos T; um supressivo e outro estimulatório. A reconstituição de camundongos nude com células T de camundongos BALB/c (Nu/+) parece reduzir ou "By-pass" a atividade supressora das células T, o qual leva à formação de uma resposta imune protetora por alguns dos camundongos nude.Athymic BALB/c (Nu/Nu) mice died at 7-13 days after inoculation (DAI) of Plasmodium berghei NK65, whereas their heterozygous (Nu/+) littermates died at 7-8 DAI. Nude (Nu/Nu) mice, reconstituted with 2 x 10(7) splenocytes from uninfected heterozygous (Nu/+) littermates at 20 days before parasite inoculation (DBI), died about 2 days earlier than control nude mice; nude mice reconstituted at 10 or 2 DBI lived 2 to 4 days longer than control nudes; and nude mice reconstituted 2 DAI lived even longer and some survived. These findings indicate that P. berghei NK65 induces at least two T-cell dependent immune phenomena, one suppressive and the other stimulatory. Reconstitution of nude mice with T-cells from BALB/c (Nu/+) mice appeared to reduce or bypass suppressive T-cell activities which allowed the formation of a protective immune response by some of the nude mice
Swine in Confinement - Feeding
It\u27s no news that hog feeding has moved out of the slopping stage. With the movement from pasture to houses and the shift from a small number of slop-fed hogs to larger scale production, swine producers soon learned that when swine are confined without vegetation, more care had to be taken with rations. And, with feed costs accounting for two-thirds to nearly nine-tenths of the total production cost, no wonder so much attention has been paid to rations, feeds, and feeding
A natural stochastic extension of the sandpile model on a graph
We introduce a new model of a stochastic sandpile on a graph containing a
sink. When unstable, a site sends one grain to each of its neighbours
independently with probability . For , this coincides with
the standard Abelian sandpile model. In general, for , the set of
recurrent configurations of this sandpile model is different from that of the
Abelian sandpile model. We give a characterisation of this set in terms of
orientations of the graph . We also define the lacking polynomial as
the generating function counting this set according to the number of grains,
and show that this polynomial satisfies a recurrence which resembles that of
the Tutte polynomial
Simulation of Heavily Irradiated Silicon Pixel Sensors and Comparison with Test Beam Measurements
Charge collection measurements performed on heavily irradiated p-spray DOFZ
pixel sensors with a grazing angle hadron beam provide a sensitive
determination of the electric field within the detectors. The data are compared
with a complete charge transport simulation of the sensor which includes signal
trapping and charge induction effects. A linearly varying electric field based
upon the standard picture of a constant type-inverted effective doping density
is inconsistent with the data. A two-trap double junction model implemented in
the ISE TCAD software can be tuned to produce a doubly-peaked electric field
which describes the data reasonably well. The modeled field differs somewhat
from previous determinations based upon the transient current technique. The
model can also account for the level of charge trapping observed in the data.Comment: 8 pages, 11 figures. Talk presented at the 2004 IEEE Nuclear Science
Symposium, October 18-21, Rome, Italy. Submitted to IEEE Transactions on
Nuclear Scienc
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International Conference on Knowledge Management
The 17th International Conference on Knowledge Management was held in the historic city of Potsdam, Germany. Since the conference was among the first post-pandemic face to face conferences, the overall theme of the 17th edition of the ICKM conference rightly focused on “Knowledge, Uncertainty and Risks: From individual to global scale” at different levels of analysis and agency. This poster highlights the qualitative study which was conducted in a major regional hospital in Germany, using the FRAM to analyze the recurrent and complex process of surgical care preparation in the morning. The aim was to offer the hospital a detailed qualitative analysis to promote resilience and maintain a safe state of operating during this process. The FRAM illustrated relevant system functions and unveiled sources as well as effects or variabilities that are now in the process of being evaluated according to appropriate goals and values. In this way, the FRAM illuminates hidden but relevant knowledge, so to speak tacit knowledge, within a complex sociotechnical system that is difficult or impossible to identify otherwise
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