4,233 research outputs found
Determinants of seasonal influenza vaccination in pregnant women in Valencia, Spain
Background: In most countries the coverage of seasonal influenza vaccination in pregnant women is low. We investigated the acceptance, reasons for rejection and professional involvement related to vaccine information in pregnant women in Valencia, Spain. Methods: Observational retrospective study in 200 pregnant women, 100 vaccinated and 100 unvaccinated, were interviewed during the 2014/2015 vaccination campaign. Electronic medical records, immunization registry and telephone interviews were used to determine reasons for vaccination and immunization rejection. Results: 40.5% of pregnant women in the health department were vaccinated. The midwife was identified as source of information for 89% of women. The vaccine was rejected due to low perceptions of risk of influenza infection (23%), lack of information (19%), considering the vaccine as superfluous (16%), close proximity of delivery date (13%) and fear of side effects (12%). Conclusion: Pregnant women in Spain declined to be vaccinated due to under-estimation of the risk of contracting or being harmed by influenza, and lack of information. Interventions aiming to optimize vaccination coverage should include information addressing the safety and effectiveness of the current vaccine together with improved professional training and motivation
Study of CP violation in Dalitz-plot analyses of B0 --> K+K-KS, B+ --> K+K-K+, and B+ --> KSKSK+
We perform amplitude analyses of the decays , , and , and measure CP-violating
parameters and partial branching fractions. The results are based on a data
sample of approximately decays, collected with the
BABAR detector at the PEP-II asymmetric-energy factory at the SLAC National
Accelerator Laboratory. For , we find a direct CP asymmetry
in of , which differs
from zero by . For , we measure the
CP-violating phase .
For , we measure an overall direct CP asymmetry of
. We also perform an angular-moment analysis of
the three channels, and determine that the state can be described
well by the sum of the resonances , , and
.Comment: 35 pages, 68 postscript figures. v3 - minor modifications to agree
with published versio
Combined search for the standard model Higgs boson decaying to a bb pair using the full CDF data set
We combine the results of searches for the standard model Higgs boson based
on the full CDF Run II data set obtained from sqrt(s) = 1.96 TeV p-pbar
collisions at the Fermilab Tevatron corresponding to an integrated luminosity
of 9.45/fb. The searches are conducted for Higgs bosons that are produced in
association with a W or Z boson, have masses in the range 90-150 GeV/c^2, and
decay into bb pairs. An excess of data is present that is inconsistent with the
background prediction at the level of 2.5 standard deviations (the most
significant local excess is 2.7 standard deviations).Comment: To be published in Phys. Rev. Lett (v2 contains minor updates based
on comments from PRL
Evidence for t\bar{t}\gamma Production and Measurement of \sigma_t\bar{t}\gamma / \sigma_t\bar{t}
Using data corresponding to 6.0/fb of ppbar collisions at sqrt(s) = 1.96 TeV
collected by the CDF II detector, we present a cross section measurement of
top-quark pair production with an additional radiated photon. The events are
selected by looking for a lepton, a photon, significant transverse momentum
imbalance, large total transverse energy, and three or more jets, with at least
one identified as containing a b quark. The ttbar+photon sample requires the
photon to have 10 GeV or more of transverse energy, and to be in the central
region. Using an event selection optimized for the ttbar+photon candidate
sample we measure the production cross section of, and the ratio of cross
sections of the two samples. Control samples in the dilepton+photon and
lepton+photon+\met, channels are constructed to aid in decay product
identification and background measurements. We observe 30 ttbar+photon
candidate events compared to the standard model expectation of 26.9 +/- 3.4
events. We measure the ttbar+photon cross section to be 0.18+0.08 pb, and the
ratio of the cross section of ttbar+photon to ttbar to be 0.024 +/- 0.009.
Assuming no ttbar+photon production, we observe a probability of 0.0015 of the
background events alone producing 30 events or more, corresponding to 3.0
standard deviations.Comment: 9 pages, 3 figure
Precision Top-Quark Mass Measurements at CDF
We present a precision measurement of the top-quark mass using the full
sample of Tevatron TeV proton-antiproton collisions collected
by the CDF II detector, corresponding to an integrated luminosity of 8.7
. Using a sample of candidate events decaying into the
lepton+jets channel, we obtain distributions of the top-quark masses and the
invariant mass of two jets from the boson decays from data. We then compare
these distributions to templates derived from signal and background samples to
extract the top-quark mass and the energy scale of the calorimeter jets with
{\it in situ} calibration. The likelihood fit of the templates from signal and
background events to the data yields the single most-precise measurement of the
top-quark mass, \mtop = 172.85 \pm\pmComment: submitted to Phys. Rev. Let
A search for resonant production of pairs in $4.8\ \rm{fb}^{-1}p\bar{p}\sqrt{s}=1.96\ \rm{TeV}$
We search for resonant production of tt pairs in 4.8 fb^{-1} integrated
luminosity of ppbar collision data at sqrt{s}=1.96 TeV in the lepton+jets decay
channel, where one top quark decays leptonically and the other hadronically. A
matrix element reconstruction technique is used; for each event a probability
density function (pdf) of the ttbar candidate invariant mass is sampled. These
pdfs are used to construct a likelihood function, whereby the cross section for
resonant ttbar production is estimated, given a hypothetical resonance mass and
width. The data indicate no evidence of resonant production of ttbar pairs. A
benchmark model of leptophobic Z \rightarrow ttbar is excluded with m_{Z'} <
900 GeV at 95% confidence level.Comment: accepted for publication in Physical Review D Sep 21, 201
Measurement of the Cross Section and Triple Gauge Couplings in Collisions at TeV
This Letter describes the current most precise measurement of the
production cross section as well as limits on anomalous couplings at a
center-of-mass energy of 1.96 TeV in proton-antiproton collisions for the
Collider Detector at Fermilab (CDF). candidates are reconstructed from
decays containing three charged leptons and missing energy from a neutrino,
where the charged leptons are either electrons or muons. Using data collected
by the CDF II detector (7.1 fb of integrated luminosity), 63 candidate
events are observed with the expected background contributing events.
The measured total cross section pb is in good
agreement with the standard model prediction of . The same sample
is used to set limits on anomalous couplings.Comment: Resubmission to PRD-RC after acceptance (27 July 2012
Measurement of branching ratio and Bs0 lifetime in the decay Bs0 -> J/psi f0(980) at CDF
We present a study of Bs0 decays to the CP-odd final state J/psi f0(980) with
J/psi -> mu+ mu- and f0(980) -> pi+ pi-. Using ppbar collision data with an
integrated luminosity of 3.8/fb collected by the CDF II detector at the
Tevatron we measure a Bs0 lifetime of tau(Bs0 -> J/psi f0(980)) = 1.70
-0.11+0.12(stat) +-0.03(syst) ps. This is the first measurement of the Bs0
lifetime in a decay to a CP eigenstate and corresponds in the standard model to
the lifetime of the heavy Bs0 eigenstate. We also measure the product of
branching fractions of Bs0 -> J/psi f0(980) and f0(980) -> pi+ pi- relative to
the product of branching fractions of Bs0 -> J/psi phi and phi -> K+ K- to be
R_f0/phi = 0.257 +_0.020(stat) +-0.014(syst), which is the most precise
determination of this quantity to date.Comment: accepted by Phys. Rev.
Search for the Higgs boson in events with missing transverse energy and b quark jets produced in proton-antiproton collisions at s**(1/2)=1.96 TeV
We search for the standard model Higgs boson produced in association with an
electroweak vector boson in events with no identified charged leptons, large
imbalance in transverse momentum, and two jets where at least one contains a
secondary vertex consistent with the decay of b hadrons. We use ~1 fb-1
integrated luminosity of proton-antiproton collisions at s**(1/2)=1.96 TeV
recorded by the CDF II experiment at the Tevatron. We find 268 (16) single
(double) b-tagged candidate events, where 248 +/- 43 (14.4 +/- 2.7) are
expected from standard model background processes. We place 95% confidence
level upper limits on the Higgs boson production cross section for several
Higgs boson masses ranging from 110 GeV/c2 to 140 GeV/c2. For a mass of 115
GeV/c2 the observed (expected) limit is 20.4 (14.2) times the standard model
prediction.Comment: 8 pages, 2 figures, submitted to Phys. Rev. Let
Precise measurement of the W-boson mass with the CDF II detector
We have measured the W-boson mass MW using data corresponding to 2.2/fb of
integrated luminosity collected in proton-antiproton collisions at 1.96 TeV
with the CDF II detector at the Fermilab Tevatron collider. Samples consisting
of 470126 W->enu candidates and 624708 W->munu candidates yield the measurement
MW = 80387 +- 12 (stat) +- 15 (syst) = 80387 +- 19 MeV. This is the most
precise measurement of the W-boson mass to date and significantly exceeds the
precision of all previous measurements combined
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