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[show abstract]
[hide abstract]
ABSTRACT: During 25 July–3 August 2001 a comprehensive cruise was undertaken along the western coast of the Republic of Ireland to resolve the three-dimensional density field and circulation. Towed undulating CTD revealed the strong thermocline beyond the 60 m contour with more diffuse stratification inshore. Argos drifters deployed in the late summer of 1999, 2000 and 2001 demonstrated strongly northward flow, their motion was uncorrelated with wind forcing but was consistent with the predicted geostrophic currents generated by the bottom fronts intersecting the seabed. These flows were evident in the data from the vessel mounted 153.6 kHz acoustic Doppler current profiler (ADCP) although the jets are relatively narrow (15–20 km).This region is heavily influenced by storm events and Atlantic influence with high salinity contributing to strong vertical and horizontal density gradients particularly in the south of the region. However, the seasonal heating cycle coupled with tidal mixing is the dominant force of buoyancy production that ensures that the frontal features occur every year.In combination with similar features found in the Celtic Sea [Brown, J., et al., 2003. Observations of the physical structure and seasonal jet-like circulation of the Celtic Sea and St. George's Channel of the Irish Sea. Continental Shelf Research 23, 533–561] these observations demonstrate the existence of a continuous pathway in summer from the north Cornish coast to Malin Head with average residual velocities >7.5 cm s−1.The data set described here provides the necessary basis for environmental management and knowledge of the pathway for contaminants, the dynamics of nutrients and an understanding of the movement of larvae and juvenile fish, in a geographic location that had previously been little studied.
Continental Shelf Research 02/2013; · 2.09 Impact Factor
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T G Hinton,
J Garnier-Laplace,
H Vandenhove,
M Dowdall,
C Adam-Guillermin,
F Alonzo,
C Barnett,
K Beaugelin-Seiller,
N A Beresford,
C Bradshaw, [......],
T Ikäheimonen,
J C Mora,
D Oughton,
A Real,
B Salbu,
M Simon-Cornu,
M Steiner,
L Sweeck,
J Vives,
I Batlle
[show abstract]
[hide abstract]
ABSTRACT: a b s t r a c t With intentions of integrating a portion of their respective research efforts into a trans-national pro-gramme that will enhance radioecology, eight European organisations recently formed the European Radioecology ALLIANCE (www.er-alliance.org). The ALLIANCE is an Association open to other organisa-tions throughout the world with similar interests in promoting radioecology. The ALLIANCE members recognised that their shared radioecological research could be enhanced by efficiently pooling resources among its partner organizations and prioritising group efforts along common themes of mutual interest. A major step in this prioritisation process was to develop a Strategic Research Agenda (SRA). An EC-funded Network of Excellence in Radioecology, called STAR (Strategy for Allied Radioecology), was formed, in part, to develop the SRA. This document is the first published draft of the SRA. The SRA outlines a suggested prioritisation of research topics in radioecology, with the goal of improving research efficiency and more rapidly advancing the science. It responds to the question: "What topics, if critically addressed over the next 20 years, would significantly advance radioecology?" The three Scientific Challenges presented within the SRA, with their 15 associated research lines, are a strategic vision of what radio-ecology can achieve in the future. Meeting these challenges will require a directed effort and collabo-ration with many organisations the world over. Addressing these challenges is important to the advancement of radioecology and in providing scientific knowledge to decision makers. Although the development of the draft SRA has largely been a European effort, the hope is that it will initiate an open dialogue within the international radioecology community and its stakeholders. This is an abbreviated document with the intention of introducing the SRA and inviting contributions from interested stake-holders. Critique and input for improving the SRA are welcomed via a link on the STAR website (www. star-radioecology.org).
Journal of environmental radioactivity 01/2013; 115:73-82. · 1.47 Impact Factor
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T G Hinton,
J Garnier-Laplace,
H Vandenhove,
M Dowdall,
C Adam-Guillermin,
F Alonzo,
C Barnett,
K Beaugelin-Seiller,
N A Beresford,
C Bradshaw, [......],
B J Howard,
T Ikäheimonen,
J C Mora,
D Oughton,
A Real,
B Salbu,
M Simon-Cornu,
M Steiner,
L Sweeck,
J Vives I Batlle
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The CDF,
collaborations,
T. Aaltonen,
V. M. Abazov,
B. Abbott,
B. S. Acharya,
M. Adams,
T. Adams,
G. D. Alexeev,
G. Alkhazov, [......],
J. Zennamo,
T. Zhao,
T. G. Zhao,
B. Zhou,
C. Zhou,
J. Zhu,
M. Zielinski,
D. Zieminska,
L. Zivkovic,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: The top quark is the heaviest known elementary particle, with a mass about 40
times larger than the mass of its isospin partner, the bottom quark. It decays
almost 100% of the time to a $W$ boson and a bottom quark. Using top-antitop
pairs at the Tevatron proton-antiproton collider, the CDF and {\dzero}
collaborations have measured the top quark's mass in different final states for
integrated luminosities of up to 5.8 fb$^{-1}$. This paper reports on a
combination of these measurements that results in a more precise value of the
mass than any individual decay channel can provide. It describes the treatment
of the systematic uncertainties and their correlations. The mass value
determined is $173.18 \pm 0.56 \thinspace ({\rm stat}) \pm 0.75 \thinspace
({\rm syst})$ GeV or $173.18 \pm 0.94$ GeV, which has a precision of $\pm
0.54%$, making this the most precise determination of the top quark mass.
07/2012;
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[show abstract]
[hide abstract]
ABSTRACT: The effects of chemical mechanical polish (CMP) and pre-growth oxidation and etching of vicinal 4H−SiC substrates on the quality
of epitaxial films have been investigated. Samples with and without a collodial silica CMP and oxidation/etch treatment were
studied with optical microscopy, cross section transmission electron microscopy (TEM) and atomic force microscopy (AFM) before
and after chemical vapor deposition. Evidence of polishing damage was evident prior to growth in all samples without CMP treatment.
Oxidation and etching appeared to generate defects by preferential etching of bulk defects such as dislocations and low angle
grain boundaries. Evidence of the polishing damage remained after chemical vapor deposition (CVD) growth on the samples without
CMP and the defect density was worse for the oxidized samples compared to the unoxidized ones. The unoxidized CMP wafer had
the lowest defect density and rms roughness of the samples studied.
Journal of Electronic Materials 04/2012; 30(3):228-234. · 1.47 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: The objective of this study was to compare the relative conspicuity of bone metastases on short-tau inversion recovery (STIR) and diffusion-weighted MRI (DWI) whole-body MR sequences for breast, prostate and myeloma malignancies.
44 whole-body MRI scans were reviewed retrospectively (coronal T(1) weighted, STIR and DWI with b=800). On each scan, up to four of the largest bone lesions were identified on T(1) weighting, and the region of interest signal intensity was measured on STIR and DWI, as well as the background signal intensity. The mean lesion signal to background ratio was calculated for each patient and then for each malignancy group.
In prostate cancer patients, the DWI signal/background ratio was greater than that of STIR in 22 out of 24 patients (mean DWI lesion/background ratio 3.91, mean STIR lesion/background ratio 2.31; p=0.0001). In multiple myeloma, the DWI ratio was higher in 6/7 patients (DWI group mean ratio 7.59, STIR group mean ratio 3.7; p=0.0366). In 13 breast cancer patients, mean STIR and DWI signal/background were similar (DWI group mean ratio 4.13, group mean STIR ratio 4.26; p=0.8587).
Bone lesion conspicuity measured by lesion/background signal intensity was higher on DWI b=800 than on STIR in patients with prostate cancer and multiple myeloma. DWI should be used in whole-body MR oncology protocols in these conditions to maximise lesion detection.
The British journal of radiology 03/2012; 85(1016):1102-6. · 2.11 Impact Factor
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The CDF,
Collaborations: T. Aaltonen,
V. M. Abazov,
B. Abbott,
B. S. Acharya,
M. Adams,
T. Adams,
G. D. Alexeev,
G. Alkhazov,
A. Alton, [......],
J. C. Yun,
A. Zanetti,
Y. Zeng,
T. Zhao,
B. Zhou,
J. Zhu,
M. Zielinski,
D. Zieminska,
L. Zivkovic,
S. Zucchelli
[show abstract]
[hide abstract]
ABSTRACT: We report the combination of recent measurements of the helicity of the W
boson from top quark decay by the CDF and D0 collaborations, based on data
samples corresponding to integrated luminosities of 2.7 - 5.4 fb^-1 of ppbar
collisions collected during Run II of the Fermilab Tevatron Collider. Combining
measurements that simultaneously determine the fractions of W bosons with
longitudinal (f0) and right-handed (f+) helicities, we find f0 = 0.722 \pm
0.081 [\pm 0.062 (stat.) \pm 0.052 (syst.)] and f+ = -0.033 \pm 0.046 [\pm
0.034 (stat.) \pm 0.031 (syst.)]. Combining measurements where one of the
helicity fractions is fixed to the value expected in the standard model, we
find f0 = 0.682 \pm 0.057 [\pm 0.035 (stat.) \pm 0.046 (syst.)] and f+ =
-0.015\pm0.035 [\pm 0.018 (stat.) \pm 0.030 (syst.)]. The results are
consistent with standard model expectations.
02/2012;
-
Collaboration,
V. M. Abazov,
B. Abbott,
B. S. Acharya,
M. Adams,
T. Adams,
G. D. Alexeev,
G. Alkhazov,
A. Alton,
G. Alverson, [......],
Z. Ye,
H. Yin,
K. Yip,
S. W. Youn,
T. Zhao,
B. Zhou,
J. Zhu,
M. Zielinski,
D. Zieminska,
L. Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We present a search for the pair production of scalar top quarks
($\tilde{t}_{1}$), the lightest supersymmetric partners of the top quarks, in
$p\bar{p}$ collisions at a center-of-mass energy of 1.96 TeV, using data
corresponding to an integrated luminosity of {7.3 $fb^{-1}$} collected with the
\dzero experiment at the Fermilab Tevatron Collider. Each scalar top quark is
assumed to decay into a $b$ quark, a charged lepton, and a scalar neutrino
($\tilde{\nu}$). We investigate final states arising from $\tilde{t}_{1}
\bar{\tilde{t}_{1}} \rightarrow b\bar{b}\mu\tau \tilde{\nu} \tilde{\nu}$ and
$\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\tau\tau \tilde{\nu}
\tilde{\nu}$. With no significant excess of events observed above the
background expected from the standard model, we set exclusion limits on this
production process in the ($m_{\tilde{t}_{1}}$,$m_{\tilde{\nu}}$) plane.
02/2012;
-
V M Abazov,
B Abbott,
B S Acharya,
M Adams,
T Adams,
G D Alexeev,
G Alkhazov,
A Alton,
G Alverson,
G A Alves, [......],
K Yip,
S W Youn,
J Yu,
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We measure the top quark mass (m(t)) in p ̄p collisions at a center of mass energy √s = 1.96 TeV using dilepton t ̄t→W(+)bW(-) ̄b→ℓ(+)ν(ℓ)bℓ(-) ̄ν(ℓ) ̄b events, where ℓ denotes an electron, a muon, or a tau that decays leptonically. The data correspond to an integrated luminosity of 5.4 fb(-1) collected with the D0 detector at the Fermilab Tevatron Collider. We obtain m(t)=174.0±1.8(stat)±2.4(syst) GeV, which is in agreement with the current world average m(t)=173.3±1.1 GeV. This is currently the most precise measurement of m(t) in the dilepton channel.
Physical Review Letters 08/2011; 107(8):082004. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
B S Acharya,
M Adams,
T Adams,
G D Alexeev,
G Alkhazov,
A Alton,
G Alverson,
G A Alves, [......],
K Yip,
S W Youn,
J Yu,
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We present a search for pair production of a fourth generation t' quark and its antiparticle, followed by their decays to a W boson and a jet, based on an integrated luminosity of 5.3 fb(-1) of proton-antiproton collisions at √s = 1.96 TeV collected by the D0 Collaboration at the Fermilab Tevatron Collider. We set upper limits on the t' ̄t' production cross section that exclude at the 95% C.L. a t' quark that decays exclusively to W+jet with a mass below 285 GeV. We observe a small excess in the μ+jets channel which reduces the mass range excluded compared to the expected limit of 320 GeV in the absence of a signal.
Physical Review Letters 08/2011; 107(8):082001. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
B S Acharya,
M Adams,
T Adams,
G D Alexeev,
G Alkhazov,
A Alton,
G Alverson,
G A Alves, [......],
K Yip,
S W Youn,
J Yu,
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We determine the fraction of tt events with spin correlation, assuming that the spin of the top quark is either correlated with the spin of the top antiquark as predicted by the standard model or is uncorrelated. For the first time we use a matrix-element-based approach to study tt spin correlation. We use tt → W+ b W- b → ℓ+ νbℓ- ν b final states produced in pp collisions at a center-of-mass energy sqrt(s)=1.96 TeV, where ℓ denotes an electron or a muon. The data correspond to an integrated luminosity of 5.4 fb(-1) and were collected with the D0 detector at the Fermilab Tevatron collider. The result agrees with the standard model prediction. We exclude the hypothesis that the spins of the tt are uncorrelated at the 97.7% C.L.
Physical Review Letters 07/2011; 107(3):032001. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
B S Acharya,
M Adams,
T Adams,
G D Alexeev,
G Alkhazov,
A Alton,
G Alverson,
G A Alves, [......],
K Yip,
S W Youn,
J Yu,
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We search for resonant WW or WZ production by using up to 5.4 fb(-1) of integrated luminosity collected by the D0 experiment in run II of the Fermilab Tevatron Collider. The data are consistent with the standard model background expectation, and we set limits on a resonance mass by using the sequential standard model W' boson and the Randall-Sundrum model graviton G as benchmarks. We exclude a sequential standard model W' boson in the mass range 180-690 GeV and a Randall-Sundrum graviton in the range 300-754 GeV at 95% C.L.
Physical Review Letters 07/2011; 107(1):011801. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
B S Acharya,
M Adams,
T Adams,
G D Alexeev,
G Alkhazov,
A Alton,
G Alverson,
G A Alves, [......],
K Yip,
S W Youn,
J Yu,
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We present a study of the dijet invariant mass spectrum in events with two jets produced in association with a W boson in data corresponding to an integrated luminosity of 4.3 fb(-1) collected with the D0 detector at √s = 1.96 TeV. We find no evidence for anomalous resonant dijet production and derive upper limits on the production cross section of an anomalous dijet resonance recently reported by the CDF Collaboration, investigating the range of dijet invariant mass from 110 to 170 GeV/c(2). The probability of the D0 data being consistent with the presence of a dijet resonance with 4 pb production cross section at 145 GeV/c(2) is 8×10(-6).
Physical Review Letters 07/2011; 107(1):011804. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
B S Acharya,
M Adams,
T Adams,
G D Alexeev,
G Alkhazov,
A Alton,
G Alverson,
G A Alves, [......],
K Yip,
S W Youn,
J Yu,
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We present a search for hypothetical vectorlike quarks in pp ̅ collisions at √s=1.96 TeV. The data were collected by the D0 detector at the Fermilab Tevatron Collider and correspond to an integrated luminosity of 5.4 fb(-1). We select events with a final state composed of a W or Z boson and a jet consistent with a heavy object decay. We observe no significant excess in comparison to the background prediction and set limits on production cross sections for vectorlike quarks decaying to W+jet and Z+jet. These are the most stringent limits to date for electroweak single vectorlike quark production at hadron colliders.
Physical Review Letters 02/2011; 106(8):081801. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
M Abolins,
B S Acharya,
M Adams,
T Adams,
G D Alexeev,
G Alkhazov,
A Alton,
G Alverson, [......],
H D Yoo,
S W Youn,
J Yu,
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We extract the total width of the top quark, Γ(t), from the partial decay width Γ(t → Wb) measured using the t-channel cross section for single top-quark production and from the branching fraction B(t → Wb) measured in tt events using up to 2.3 fb(-1) of integrated luminosity collected by the D0 Collaboration at the Tevatron pp Collider. The result is Γ(t) = 1.99(-0.55)(+0.69) GeV, which translates to a top-quark lifetime of τ(t) = (3.3(-0.9)(+1.3)) × 10(-25) s. Assuming a high mass fourth generation b' quark and unitarity of the four-generation quark-mixing matrix, we set the first upper limit on |V(tb')| < 0.63 at 95% C.L.
Physical Review Letters 01/2011; 106(2):022001. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
M Abolins,
B S Acharya,
M Adams,
T Adams,
G D Alexeev,
G Alkhazov,
A Alton,
G Alverson, [......],
H D Yoo,
S W Youn,
J Yu,
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We present a search for the standard model Higgs boson produced in association with a Z boson in 4.2 fb(-1) of pp collisions, collected with the D0 detector at the Fermilab Tevatron at sqrt[s] =1 .96 TeV. Selected events contain one reconstructed Z → e+ e- or Z → μ+ μ- candidate and at least two jets, including at least one b-tagged jet. In the absence of an excess over the background expected from other standard model processes, limits on the ZH cross section multiplied by the branching ratios are set. The limit at M(H) = 115 GeV is a factor of 5.9 larger than the standard model prediction.
Physical Review Letters 12/2010; 105(25):251801. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
M Abolins,
B S Acharya,
M Adams,
T Adams,
G D Alexeev,
G Alkhazov,
A Alton,
G Alverson, [......],
S W Youn,
J Yu,
S Zelitch,
T Zhao,
B Zhou,
N Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We report a search for diphoton events with large missing transverse energy produced in pp collisions at √s=1.96 TeV. The data were collected with the D0 detector at the Fermilab Tevatron Collider and correspond to 6.3 fb(-1) of integrated luminosity. The observed missing transverse energy distribution is well described by the standard model prediction, and 95% C.L. limits are derived on two realizations of theories beyond the standard model. In a gauge-mediated supersymmetry breaking scenario, the breaking scale Λ is excluded for Λ<124 TeV. In a universal extra dimension model including gravitational decays, the compactification radius R(c) is excluded for R(c)(-1)<477 GeV.
Physical Review Letters 11/2010; 105(22):221802. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
M Abolins,
B S Acharya,
M Adams,
T Adams,
G D Alexeev,
G Alkhazov,
A Alton,
G Alverson, [......],
H D Yoo,
S W Youn,
J Yu,
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We report the results of a search for R parity violating (RPV) interactions leading to the production of supersymmetric sneutrinos decaying into eμ final states using 5.3 fb-1 of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider. Having observed no evidence for production of eμ resonances, we set direct bounds on the RPV couplings λ311' and λ312 as a function of sneutrino mass.
Physical Review Letters 11/2010; 105(19):191802. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
M Abolins,
B S Acharya,
M Adams,
T Adams,
G D Alexeev,
G Alkhazov,
A Alton,
G Alverson, [......],
H D Yoo,
S W Youn,
J Yu,
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We present the first search for pair production of isolated jets of charged leptons in association with a large imbalance in transverse energy in pp collisions using 5.8 fb⁻¹ of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider. No excess is observed above the standard model background, and the result is used to set upper limits on the production cross section of pairs of supersymmetric chargino and neutralino particles as a function of "dark-photon" mass, where the dark photon is produced in the decay of the lightest supersymmetric particle.
Physical Review Letters 11/2010; 105(21):211802. · 7.37 Impact Factor
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V M Abazov,
B Abbott,
M Abolins,
B S Acharya,
M Adams,
T Adams,
G D Alexeev,
G Alkhazov,
A Alton,
G Alverson, [......],
H D Yoo,
S W Youn,
J Yu,
S Zelitch,
T Zhao,
B Zhou,
J Zhu,
M Zielinski,
D Zieminska,
L Zivkovic
[show abstract]
[hide abstract]
ABSTRACT: We report results of a search for particles with anomalously high ionization in events with a high transverse energy jet and large missing transverse energy in 2.4 fb⁻¹ of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron pp collider. Production of such particles (quirks) is expected in scenarios with extra QCD-like SU(N) sectors, and this study is the first dedicated search for such signatures. We find no evidence of a signal and set a lower mass limit of 107, 119, and 133 GeV for the mass of a charged quirk with strong dynamics scale Λ in the range from 10 keV to 1 MeV and N=2, 3, and 5, respectively.
Physical Review Letters 11/2010; 105(21):211803. · 7.37 Impact Factor
