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Author |
CDF Collaboration (Aaltonen, T. et al); Cabrera, S. |
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Title |
Search for single top quark production in p(p)over-bar collisions at root s=1.96 TeV in the missing transverse energy plus jets topology |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
81 |
Issue |
7 |
Pages |
072003 - 24pp |
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Keywords |
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Abstract |
We report a search for single top quark production with the CDF II detector using 2: 1 fb(-1) of integrated luminosity of p (p) over bar collisions at root s = 1.96 TeV. The data selected consist of events characterized by large energy imbalance in the transverse plane and hadronic jets, and no identified electrons and muons, so the sample is enriched in W -> tau nu decays. In order to suppress backgrounds, additional kinematic and topological requirements are imposed through a neural network, and at least one of the jets must be identified as a b quark jet. We measure an excess of signal-like events in agreement with the standard model prediction, but inconsistent with a model without single top quark production by 2.1 standard deviations (sigma), with a median expected sensitivity of 1.4 sigma. Assuming a top quark mass of 175 GeV/c(2) and ascribing the excess to single top quark production, the cross section is measured to be 4.9(-2.2)(+2.5) (stat + syst) pb, consistent with measurements performed in independent data sets and with the standard model prediction. |
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Address |
[Aaltonen, T.; Mehtala, P.; Orava, R.; Osterberg, K.; Saarikko, H.; van Remortel, N.] Univ Helsinki, Div High Energy Phys, Dept Phys, FIN-00014 Helsinki, Finland |
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Amer Physical Soc |
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English |
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1550-7998 |
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Notes  |
ISI:000277201900007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
287 |
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Author |
Fernandez-Martinez, E.; Li, T.; Pascoli, S.; Mena, O. |
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Title |
Improvement of the low energy neutrino factory |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
81 |
Issue |
7 |
Pages |
073010 - 13pp |
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Keywords |
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Abstract |
The low energy neutrino factory has been proposed as a very sensitive setup for future searches for CP violation and matter effects. Here we study how its performance is affected when the experimental specifications of the setup are varied. Most notably, we have considered the addition of the “platinum'' nu(mu) -> nu(e) channel. We find that, while theoretically the extra channel provides very useful complementary information and helps to lift degeneracies, its practical usefulness is lost when considering realistic background levels. Conversely, an increase in statistics in the ”golden'' nu(mu) -> nu(e) channel and, to some extent, an improvement in the energy resolution, lead to an important increase in the performance of the facility, given the rich energy dependence of the "golden'' channel at these energies. We show that a low energy neutrino factory with a baseline of 1300 km, muon energy of 4.5 GeV, and either a 20 kton totally active scintillating detector or 100 kton liquid argon detector, can have outstanding sensitivity to the neutrino oscillation parameters theta(13), delta, and the mass hierarchy. For our estimated exposure of 2: 8 x 10(23) kton x decays per muon polarity, the low energy neutrino factory has sensitivity to theta(13) and delta for sin(2)(2 theta(13)) > 10(-4) and to the mass hierarchy for sin(2)(2 theta(13)) > 10(-3) |
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Address |
[Martinez, Enrique Fernandez] Max Planck Inst Phys & Astrophys, Werner Heisenberg Inst, D-80805 Munich, Germany, Email: enfmarti@mppmu.mpg.de |
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Amer Physical Soc |
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English |
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1550-7998 |
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ISI:000277201900018 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
458 |
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Author |
Gonzalez-Alonso, M.; Pich, A.; Prades, J. |
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Title |
Violation of quark-hadron duality and spectral chiral moments in QCD |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
81 |
Issue |
7 |
Pages |
074007 - 10pp |
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Abstract |
We analyze the spectral moments of the V – A two-point correlation function. Using all known short-distance constraints and the most recent experimental data from tau decays, we determine the lowest spectral moments, trying to assess the uncertainties associated with the so-called violations of quark-hadron duality. We have generated a large number of acceptable spectral functions, satisfying all conditions, and have used them to extract the wanted hadronic parameters through a careful statistical analysis. We obtain accurate values for the chi PT couplings L-10 and C-87, and a realistic determination of the dimension six and eight contributions in the operator product expansion, O-6 = (-5.4(-1.6)(+3.6)) . 10(-3) GeV6 and O-8 = d(-8.9-(12.6)(7.4+)) 10(-3) GeV8, showing that the duality-violation effects have been underestimated in previous literature. |
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Address |
[Gonzalez-Alonso, Martin; Pich, Antonio] Univ Valencia, CSIC, Dept Fis Teor, E-46071 Valencia, Spain |
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Amer Physical Soc |
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English |
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Abbreviated Series Title |
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Series Volume |
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ISSN |
1550-7998 |
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Notes |
ISI:000277201900025 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
459 |
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Author |
Bernabeu, J.; Espinoza, C.; Mavromatos, N.E. |
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Title |
Cosmological constant and local gravity |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
81 |
Issue |
8 |
Pages |
084002 - 7pp |
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Abstract |
We discuss the linearization of Einstein equations in the presence of a cosmological constant, by expanding the solution for the metric around a flat Minkowski space-time. We demonstrate that one can find consistent solutions to the linearized set of equations for the metric perturbations, in the Lorentz gauge, which are not spherically symmetric, but they rather exhibit a cylindrical symmetry. We find that the components of the gravitational field satisfying the appropriate Poisson equations have the property of ensuring that a scalar potential can be constructed, in which both contributions, from ordinary matter and Lambda > 0, are attractive. In addition, there is a novel tensor potential, induced by the pressure density, in which the effect of the cosmological constant is repulsive. We also linearize the Schwarzschild-de Sitter exact solution of Einstein's equations ( due to a generalization of Birkhoff's theorem) in the domain between the two horizons. We manage to transform it first to a gauge in which the 3-space metric is conformally flat and, then, make an additional coordinate transformation leading to the Lorentz gauge conditions. We compare our non-spherically symmetric solution with the linearized Schwarzschild-de Sitter metric, when the latter is transformed to the Lorentz gauge, and we find agreement. The resulting metric, however, does not acquire a proper Newtonian form in terms of the unique scalar potential that solves the corresponding Poisson equation. Nevertheless, our solution is stable, in the sense that the physical energy density is positive. |
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Address |
[Bernabeu, Jose; Espinoza, Catalina] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Valencia, Spain |
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Amer Physical Soc |
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English |
Summary Language |
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1550-7998 |
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Notes |
ISI:000277205000057 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
460 |
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Author |
Morisi, S.; Peinado, E. |
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Title |
S-4 model for quarks and leptons with maximal atmospheric angle |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
81 |
Issue |
8 |
Pages |
085015 - 8pp |
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Keywords |
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Abstract |
We consider a model for quark and lepton masses and mixings based on S-4 flavor symmetry. The model contains six Higgs doublets where three of them give mass to the leptons, and the other three gives mass to the quarks. Charged fermion and quark masses arise from renormalizable interactions while neutrino Majorana masses are generated through effective dimension five Weinberg operator. From the study of the minimization of the scalar potential we found a residual μ<-> tau symmetry in the neutrino sector predicting zero reactor angle and maximal atmospheric angle and for the quark sector we found a four-zero texture. We give a fit of the mass hierarchies and mixing angles in the quark sector. |
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Address |
[Morisi, Stefano; Peinado, Eduardo] Univ Valencia, CSIC, AHEP Grp, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: morisi@ific.uv.es |
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Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1550-7998 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000277205000132 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
461 |
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| Permanent link to this record |
