473 research outputs found
Global constraints on top quark anomalous couplings
The latest results on top quark physics, namely single top quark production cross sections, W-boson helicity and asymmetry measurements are used to probe the Lorentz structure of the Wtb vertex. The increase of sensitivity to new anomalous physics contributions to the top quark sector of the standard model is quantified by combining the relevant results from Tevatron and the Large Hadron Collider. The results show that combining an increasing set of available precision measurements in the search for new physics phenomena beyond the standard model leads to significant sensitivity improvements, especially when compared with the current expectation for the High Luminosity run at the LHC.This work was supported by the PSC-CUNY Grant 60061-00 48.info:eu-repo/semantics/publishedVersio
TERRISCOPE: AN OPTICAL REMOTE SENSING RESEARCH PLATFORM USING AIRCRAFT AND UAS FOR THE CHARACTERIZATION OF CONTINENTAL SURFACES
ONERA is developing TERRISCOPE, a new platform to characterize the environment and the continental surfaces by optical remote sensing using manned aircrafts and UAS (Unmanned Airborne System). The objective of TERRISCOPE is to make available to the scientific community combinations of optical measurements remotely sensed with the best level state-of-the-art sensors. Different kinds of sensors have already been acquired or are still being acquired: Hyperspectral sensors (0.5–2.5 μm range), visible high resolution cameras, multispectral infrared cameras and airborne laser scanners. Each sensor is declined in two versions: one high performance for manned aircrafts and one more compact for UAS. This paper describes the whole equipment, and presents the main characteristics and performances of the carriers, the sensors and the processing chain. Possible sensors combinations on airplanes and UAS are also presented, as well as preliminary results
Search for right-handed W bosons in top quark decay
We present a measurement of the fraction f+ of right-handed W bosons produced
in top quark decays, based on a candidate sample of events in the
lepton+jets decay mode. These data correspond to an integrated luminosity of
230pb^-1, collected by the DO detector at the Fermilab Tevatron
Collider at sqrt(s)=1.96 TeV. We use a constrained fit to reconstruct the
kinematics of the and decay products, which allows for the
measurement of the leptonic decay angle for each event. By comparing
the distribution from the data with those for the expected
background and signal for various values of f+, we find
f+=0.00+-0.13(stat)+-0.07(syst). This measurement is consistent with the
standard model prediction of f+=3.6x10^-4.Comment: Submitted to Physical Review D Rapid Communications 7 pages, 3
figure
A search for W bb and W Higgs production in ppbar collisions at sqrt(s)=1.96 TeV
We present a search for W b \bar{b} production in p \bar{p} collisions at
sqrt{s}=1.96 TeV in events containing one electron, an imbalance in transverse
momentum, and two b-tagged jets. Using 174 pb-1 of integrated luminosity
accumulated by the D0 experiment at the Fermilab Tevatron collider, and the
standard-model description of such events, we set a 95% C.L. upper limit on W b
\bar{b}WH--$135
GeV.Comment: 7 pages, 4 figures, 1 table, submitted to Physical Review Letter
Measurement of Semileptonic Branching Fractions of B Mesons to Narrow D** States
Using the data accumulated in 2002-2004 with the DO detector in
proton-antiproton collisions at the Fermilab Tevatron collider with
centre-of-mass energy 1.96 TeV, the branching fractions of the decays B ->
\bar{D}_1^0(2420) \mu^+ \nu_\mu X and B -> \bar{D}_2^{*0}(2460) \mu^+ \nu_\mu X
and their ratio have been measured: BR(\bar{b}->B) \cdot BR(B-> \bar{D}_1^0
\mu^+ \nu_\mu X) \cdot BR(\bar{D}_1^0 -> D*- pi+) =
(0.087+-0.007(stat)+-0.014(syst))%; BR(\bar{b}->B)\cdot BR(B->D_2^{*0} \mu^+
\nu_\mu X) \cdot BR(\bar{D}_2^{*0} -> D*- \pi^+) =
(0.035+-0.007(stat)+-0.008(syst))%; and (BR(B -> \bar{D}_2^{*0} \mu^+ \nu_\mu
X)BR(D2*0->D*- pi+)) / (BR(B -> \bar{D}_1^{0} \mu^+ \nu_\mu X)\cdot
BR(\bar{D}_1^{0}->D*- \pi^+)) = 0.39+-0.09(stat)+-0.12(syst), where the charge
conjugated states are always implied.Comment: submitted to Phys. Rev. Let
Measurement of the Lifetime Difference in the B_s^0 System
We present a study of the decay B_s^0 -> J/psi phi We obtain the CP-odd
fraction in the final state at time zero, R_perp = 0.16 +/- 0.10 (stat) +/-
0.02 (syst), the average lifetime of the (B_s, B_sbar) system, tau (B_s^0)
=1.39^{+0.13}_{-0.16} (stat) ^{+0.01}_{-0.02} (syst) ps, and the relative width
difference between the heavy and light mass eigenstates, Delta Gamma/Gamma =
(Gamma_L - Gamma_H)/Gamma =0.24^{+0.28}_{-0.38} (stat) ^{+0.03}_{-0.04} (syst).
With the additional constraint from the world average of the B_s^0$lifetime
measurements using semileptonic decays, we find tau (B_s^0)= 1.39 +/- 0.06 ~ps
and Delta Gamma/\Gamma = 0.25^{+0.14}_{-0.15}. For the ratio of the B_s^0 and
B^0 lifetimes we obtain tau(B_s^0)/tau(B^0)} = 0.91 +/- 0.09 (stat) +/- 0.003
(syst).Comment: submitted to Phys. Rev. Lett. FERMILAB-PUB-05-324-
Search for Large Extra Spatial Dimensions in Dimuon Production with the D0 Detector
We present the results of a search for the effects of large extra spatial
dimensions in collisions at 1.96 TeV in events
containing a pair of energetic muons. The data correspond to 246 \ipb of
integrated luminosity collected by the \D0 experiment at the Fermilab Tevatron
Collider. Good agreement with the expected background was found, yielding no
evidence for large extra dimensions. We set 95% C.L. lower limits on the
fundamental Planck scale between 0.85 TeV and 1.27 TeV within several
formalisms. These are the most stringent limits achieved in the dimuon channel
to date.Comment: 8 pages, 3 figures, 1 table. Published in Phys. Rev. Lett. Minor
changes in v2 to match the published versio
A Search for the Flavor-Changing Neutral Current Decay B0_s -> mu^+mu^- in pp(bar) Collisions at \sqrt{s} = 1.96 TeV with the D0 Detector
We present the results of a search for the flavor-changing neutral current
decay B0_s -> mu+ mu- using a data set with integrated luminosity of 240
pb^{-1} of pp(bar) collisions at sqrt{s}=1.96 TeV collected with the D0
detector in Run II of the Fermilab Tevatron collider. We find the upper limit
on the branching fraction to be Br(B0_s -> mu+ mu-) \leq 5.0 x 10^{-7} at the
95% C.L. assuming no contributions from the decay B0_d -> mu+ mu- in the signal
region. This limit is the most stringent upper bound on the branching fraction
B0_s -> mu+ mu- to date.Comment: 7 pages, 3 figures, LaTeX, to be submitted to Physical Review
Letters, minor changes to text, reference adde
Study of events and limits on anomalous and couplings in ppbar collisions at TeV
We present a measurement of the Z\gamma production cross section and limits
on anomalous ZZ\gamma and Z\gamma\gamma couplings for form-factor scales of
Lambda = 750 and 1000 GeV. The measurement is based on 138 (152) candidate
events in the ee\gamma (\mu\mu\gamma) final state using 320 (290) pb^{-1} of
ppbar collisions at \sqrt{s} = 1.96 TeV. The 95% C.L. limits on real and
imaginary parts of individual anomalous couplings are |h_{10,30}^{Z}|<0.23,
|h_{20,40}^{Z}|<0.020, |h_{10,30}^{\gamma}|<0.23, and
|h_{20,40}^{\gamma}|<0.019 for Lambda = 1000 GeV.Comment: submitted to Phys. Rev. Letter
Measurement of the Ratio of B+ and B0 Meson Lifetimes
The ratio of B+ and B0 meson lifetimes was measured using data collected in
2002-2004 by the D0 experiment in Run II of the Fermilab Tevatron Collider.
These mesons were reconstructed in B -> mu+ nu D*- X decays, which are
dominated by B0, and B ->mu+ nu D0bar X decays, which are dominated by B+. The
ratio of lifetimes is measured to be t+/t0 = 1.080 +- 0.016(stat) +-
0.014(syst).Comment: 7 pages, 2 figures, LaTeX, to be submitted to Physical Review Letter
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