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Author |
LHCb Collaboration (Aaij, R. et al); Martinez-Vidal, F.; Oyanguren, A.; Ruiz Valls, P.; Sanchez Mayordomo, C. |
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Title |
Measurement of the forward W boson cross-section in pp collisions at root s = 7 TeV |
Type |
Journal Article |
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Year |
2014 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
12 |
Issue |
12 |
Pages |
079 - 25pp |
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Keywords |
Hadron-Hadron Scattering; QCD; Forward physics |
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Abstract |
A measurement of the inclusive W -> μnu production cross-section using data from pp collisions at a centre-of-mass energy of root s=7 TeV is presented. The analysis is based on an integrated luminosity of about 1.0 fb(-1) recorded with the LHCb detector. Results are reported for muons with a transverse momentum greater than 20 GeV/c and pseudorapidity between 2.0 and 4.5. The W+ and W- production cross-sections are measured to be sigma(W+->mu+nu)=861.0 +/- 2.0 +/- 11.2 +/- 14.7pb, sigma(W-->mu-(nu)over bar)=675.8 +/- 1.9 +/- 8.8 +/- 11.6pb, where the first uncertainty is statistical, the second is systematic and the third is due to the luminosity determination. Cross-section ratios and differential distributions as functions of the muon pseudorapidity are also presented. The ratio of W+ to W- cross-sections in the same fiducial kinematic region is determined to be sigma(W+->mu+nu)/sigma(W-->mu-(nu)over bar) = 1.274 +/- 0.005 +/- 0.009, where the uncertainties are statistical and systematic, respectively. Results are in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. |
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Address |
Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil, Email: simone.bifani@cern.ch |
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Springer |
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English |
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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000346250100002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2246 |
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Author |
LHCb Collaboration (Aaij, R. et al); Martinez-Vidal, F.; Oyanguren, A.; Ruiz Valls, P.; Sanchez Mayordomo, C. |
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Title |
Search for the lepton flavour violating decay tau(-) -> mu(-)mu(+)mu(-) |
Type |
Journal Article |
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Year |
2015 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
02 |
Issue |
2 |
Pages |
121 - 20pp |
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Keywords |
Rare decay; Tau Physics; Hadron-Hadron Scattering |
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Abstract |
A search for the lepton flavour violating decay tau(-) -> mu(-)mu(+)mu(-) is performed with the LHCb experiment. The data sample corresponds to an integrated luminosity of 1.0 fb(-1) of proton-proton collisions at a centre-of-mass energy of 7 TeV and 2.0 fb(-1) at 8 TeV. No evidence is found for a signal, and a limit is set at 90% confidence level on the branching fraction, B(tau(-) -> mu(-)mu(+)mu(-)) < 4.6 x 10(-8). |
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Address |
[Bediaga, I.; De Miranda, J. M.; Rodrigues, F. Ferreira; Gomes, A.; Massafferri, A.; dos Reis, A. C.; Rodrigues, A. B.] CBPF, Rio De Janeiro, Brazil |
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Springer |
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English |
Summary Language |
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Original Title |
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Abbreviated Series Title |
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Series Volume |
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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000350332500001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2148 |
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Author |
LHCb Collaboration (Aaij, R. et al); Martinez-Vidal, F.; Oyanguren, A.; Ruiz Valls, P.; Sanchez Mayordomo, C. |
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Title |
Study of eta-eta ' mixing from measurement of B-(s)(0) -> J/psi eta((')) decay rates |
Type |
Journal Article |
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Year |
2015 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
01 |
Issue |
1 |
Pages |
024 - 24pp |
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Keywords |
Spectroscopy; Hadron-Hadron Scattering; QCD; Branching fraction; B physics |
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Abstract |
A study of B and B-s(0) meson decays into J/psi eta and J/psi eta' final states is performed using a data set of proton-proton collisions at centre-of-mass energies of 7 and 8 TeV, collected by the LCHb experiment and corresponding to 3.0 fb(-1) of integrated luminosity. The decay B-0 -> J/psi eta' is observed for the first time. The following ratios of branching fractions are measured: B(B-0 -> J psi eta')/B(B-s(0) -> J psi eta') = (2.28 +/- 0.65 (stat) +/- 0.010 (syst) +/- 0.13 (f(s)/f(d)) x 10(-2) , B(B-0 -> J psi eta')/B(B-s(0) -> J psi eta') = (1.85 +/- 0.65 (stat) +/- 0.09 (syst) +/- 0.11 (f(s)/f(d)) x 10(-2) where the third uncertainty is related to the present knowledge of f(s)/f(d), the ratio between the probabilities for a b quark to form a B-s(0) or a B-0 meson. The branching fraction ratios are used to determine the parameters of eta-eta' meson mixing. In addition, the first evidence for the decay B-s(0) -> psi(2S)' is reported, and the relative branching fraction is measured, B(B-s(0) -> psi(2S)eta')/B(B-s(0) -> J psi eta') = (38.7 +/- 9.0 (stat) +/- 1.3 (syst) +/- 0.9(B)) x 10(-2), where the third uncertainty is due to the limited knowledge of the branching fractions of J/psi and psi(2S) mesons. |
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Address |
[Bediaga, I.; Miranda, J. M. De; Ferreira Rodrigues, F.; Gomes, A.; Marchand, J. F.; Massafferri, A.; Reis, A. C. dos; Rodrigues, A. B.] CBPF, Rio De Janeiro, Brazil, Email: Ivan.Belyaev@itep.ru |
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Springer |
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English |
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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000347685500001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2077 |
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Author |
Aristizabal Sierra, D.; Degee, A.; Dorame, L.; Hirsch, M. |
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Title |
Systematic classification of two-loop realizations of the Weinberg operator |
Type |
Journal Article |
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Year |
2015 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
040 - 41pp |
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Keywords |
Beyond Standard Model; Neutrino Physics |
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Abstract |
We systematically analyze the d = 5 Weinberg operator at 2-loop order. Using a diagrammatic approach, we identify two different interesting categories of neutrino mass models: (i) Genuine 2-loop models for which both, tree-level and 1-loop contributions, are guaranteed to be absent. And (ii) finite 2-loop diagrams, which correspond to the 1-loop generation of some particular vertex appearing in a given 1-loop neutrino mass model, thus being effectively 2-loop. From the large list of all possible 2-loop diagrams, the vast majority are infinite corrections to lower order neutrino mass models and only a moderately small number of diagrams fall into these two interesting classes. Moreover, all diagrams in class (i) are just variations of three basic diagrams, with examples discussed in the literature before. Similarly, we also show that class (ii) diagrams consists of only variations of these three plus two more basic diagrams. Finally, we show how our results can be consistently and readily used in order to construct two-loop neutrino mass models. |
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Address |
[Sierra, D. Aristizabal; Degee, A.] Univ Liege, IFPA, Dept AGO, B-4000 Liege 1, Belgium, Email: daristizabal@ulg.ac.be; |
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Springer |
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English |
Summary Language |
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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000351365700002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2167 |
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Author |
Agarwalla, S.K.; Bagchi, P.; Forero, D.V.; Tortola, M. |
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Title |
Probing non-standard interactions at Daya Bay |
Type |
Journal Article |
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Year |
2015 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
07 |
Issue |
7 |
Pages |
060 - 33pp |
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Keywords |
Neutrino Physics; Beyond Standard Model |
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Abstract |
In this article we consider the presence of neutrino non-standard interactions (NSI) in the production and detection processes of reactor antineutrinos at the Daya Bay experiment. We report for the first time, the new constraints on the flavor non-universal and flavor universal charged-current NSI parameters, estimated using the currently released 621 days of Daya Bay data. New limits are placed assuming that the new physics effects are just inverse of each other in the production and detection processes. With this special choice of the NSI parameters, we observe a shift in the oscillation amplitude without distorting the L/E pattern of the oscillation probability. This shift in the depth of the oscillation dip can be caused by the NSI parameters as well as by theta(13), making it quite difficult to disentangle the NSI effects from the standard oscillations. We explore the correlations between the NSI parameters and theta(13) that may lead to significant deviations in the reported value of the reactor mixing angle with the help of iso-probability surface plots. Finally, we present the limits on electron, muon/tau, and flavor universal (FU) NSI couplings with and without considering the uncertainty in the normalization of the total event rates. Assuming a perfect knowledge of the event rates normalization, we find strong upper bounds similar to 0.1% for the electron and FU cases improving the present limits by one order of magnitude. However, for a conservative error of 5% in the total normalization, these constraints are relaxed by almost one order of magnitude. |
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Address |
[Agarwalla, Sanjib Kumar; Bagchi, Partha] Inst Phys, Bhubaneswar 751005, Orissa, India, Email: sanjib@iopb.res.in; |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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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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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000363504900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2427 |
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