4,177 research outputs found
Jet and Missing ET Reconstruction and Signatures at ATLAS and CMS
Jet and missing transverse energy reconstruction and calibration strategies and their expected performance in ATLAS and CMS experiments at the LHC are presented, together with studies of high transverse momentum signatures of jets aimed at the search for new phenomena such as boosted top quark mono-jets expected in various beyond the standard model scenarios
The CDF MiniPlug Calorimeters at the Tevatron
Two MiniPlug calorimeters, designed to measure the energy and lateral
position of particles in the pseudorapidity region of 3.6<|eta|<5.1 of the CDF
detector, have been installed as part of the Run II CDF upgrade at the Tevatron
collider. Detector performance and first results from collision data
are presented.Comment: Presented at `Frontier Detectors for Frontier Physics; 9th Pisa
Meeting on Advanced Detectors', Biodola, Italy, 25-31 May 2003. 2 page
Bearing capacity charts of soft soil reinforced by deep mixing
A series of preliminary design charts were developed to predict the bearing capacity of fully and partially penetrated deep mixing (DM) of soft soil. The charts were produced by a new numerical analysis tool based on discontinuity layout optimisation (DLO) in which a previously proposed homogenisation method was used to define the improvement area. To measure the applicability of implementation of the homogenisation method in the DLO, a series of validation processes was performed against several previous studies under uniform soil strength. A new empirical solution was developed from the DLO method using the homogenisation method for the bearing capacity of soft ground under uniform soil strength, improved by the fully penetrated DM method. Results produced by the DLO approach were compared with existing analytical solutions and better agreement was found from the present model. The charts consider variation in improvement area ratio, column length and strength, and foundation width for the fully and partially penetrated DM cases. The simulations were related to real field cases in which the strength characteristics of soft soil increase with depth. An example is given to demonstrate use of the charts
Measurement of the Lifetime Difference Between B_s Mass Eigenstates
We present measurements of the lifetimes and polarization amplitudes for B_s
--> J/psi phi and B_d --> J/psi K*0 decays. Lifetimes of the heavy (H) and
light (L) mass eigenstates in the B_s system are separately measured for the
first time by determining the relative contributions of amplitudes with
definite CP as a function of the decay time. Using 203 +/- 15 B_s decays, we
obtain tau_L = (1.05 +{0.16}/-{0.13} +/- 0.02) ps and tau_H = (2.07
+{0.58}/-{0.46} +/- 0.03) ps. Expressed in terms of the difference DeltaGamma_s
and average Gamma_s, of the decay rates of the two eigenstates, the results are
DeltaGamma_s/Gamma_s = (65 +{25}/-{33} +/- 1)%, and DeltaGamma_s = (0.47
+{0.19}/-{0.24} +/- 0.01) inverse ps.Comment: 8 pages, 3 figures, 2 tables; as published in Physical Review Letters
on 16 March 2005; revisions are for length and typesetting only, no changes
in results or conclusion
Measurement of and Production in Collisions at = 1.96 TeV
The Standard Model predictions for and production are
tested using an integrated luminosity of 200 pb of \ppbar collision data
collected at the Collider Detector at Fermilab. The cross sections are measured
selecting leptonic decays of the and bosons, and photons with
transverse energy GeV that are well separated from leptons. The
production cross sections and kinematic distributions for the and
are compared to SM predictions.Comment: 7 pages, 4 figures, submitted to PR
Inclusive Search for Anomalous Production of High-pT Like-Sign Lepton Pairs in Proton-Antiproton Collisions at sqrt{s}=1.8 TeV
We report on a search for anomalous production of events with at least two
charged, isolated, like-sign leptons with pT > 11 GeV/c using a 107 pb^-1
sample of 1.8 TeV ppbar collisions collected by the CDF detector. We define a
signal region containing low background from Standard Model processes. To avoid
bias, we fix the final cuts before examining the event yield in the signal
region using control regions to test the Monte Carlo predictions. We observe no
events in the signal region, consistent with an expectation of
0.63^(+0.84)_(-0.07) events. We present 95% confidence level limits on new
physics processes in both a signature-based context as well as within a
representative minimal supergravity (tanbeta = 3) model.Comment: 15 pages, 4 figures. Minor textual changes, cosmetic improvements to
figures and updated and expanded reference
Evidence for the exclusive decay Bc+- to J/psi pi+- and measurement of the mass of the Bc meson
We report first evidence for a fully reconstructed decay mode of the
B_c^{\pm} meson in the channel B_c^{\pm} \to J/psi \pi^{\pm}, with J/psi \to
mu^+mu^-. The analysis is based on an integrated luminosity of 360 pb$^{-1} in
p\bar{p} collisions at 1.96 TeV center of mass energy collected by the Collider
Detector at Fermilab. We observe 14.6 \pm 4.6 signal events with a background
of 7.1 \pm 0.9 events, and a fit to the J/psi pi^{\pm} mass spectrum yields a
B_c^{\pm} mass of 6285.7 \pm 5.3(stat) \pm 1.2(syst) MeV/c^2. The probability
of a peak of this magnitude occurring by random fluctuation in the search
region is estimated as 0.012%.Comment: 7 pages, 3 figures. Version 3, accepted by PR
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