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Author |
n_TOF Collaboration (Amaducci, S. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Measurement of the U-235(n, f) cross section relative to the Li-6(n, t) and B-10(n,alpha) standards from thermal to 170 keV neutron energy range at n_TOF |
Type |
Journal Article |
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Year |
2019 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
55 |
Issue |
7 |
Pages |
120 - 19pp |
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Keywords |
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Abstract |
.The U-235(n, f ) cross section was measured at n_TOF relative to Li-6(n, t) and B-10(n,alpha) , with high resolution ( L=183.49(2) m) and in a wide energy range (25meV-170keV) with 1.5% systematic uncertainty, making use of a stack of six samples and six silicon detectors placed in the neutron beam. This allowed us to make a direct comparison of the yields of the U-235(n, f ) and of the two reference reactions under the same experimental conditions, and taking into account the forward/backward emission asymmetry. A hint of an anomaly in the 10-30keV neutron energy range had been previously observed in other experiments, indicating a cross section systematically lower by several percent relative to major evaluations. The present results indicate that the cross section in the 9-18keV neutron energy range is indeed overestimated by almost 5% in the recently released evaluated data files ENDF/B-VIII.0 and JEFF3.3, as a consequence of a 7% overestimate in a single GMA node in the IAEA reference file. Furthermore, these new high-resolution data confirm the existence of resonance-like structures in the keV neutron energy region. The results here reported may lead to a reduction of the uncertainty in the 1-100keV neutron energy region. Finally, from the present data, a value of 249.7 +/- 1.4( stat )+/- 0.94( syst ) b<bold>eV has been extracted for the cross section integral between </bold>7.8 and 11eV, confirming the value of 247.5 +/- 3 b<bold>eV recently established as a standard</bold>. |
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Address  |
[Amaducci, S.; Cosentino, L.; Finocchiaro, P.; Musumarra, A.] INFN, Lab Nazl Sud, Catania, Italy, Email: finocchiaro@lns.infn.it |
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Springer |
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English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6001 |
ISBN |
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Conference |
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Notes |
WOS:000477050900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4083 |
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Author |
Amarilo, K.M.; Ferreira Filho, M.B.; Araujo Filho, A.A.; Reis, J.A.A.S. |
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Title |
Gravitational waves effects in a Lorentz-violating scenario |
Type |
Journal Article |
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Year |
2024 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
855 |
Issue |
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Pages |
138785 - 7pp |
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Keywords |
Gravitational waves; Lorentz symmetry breaking; Polarization states; Quadrupole term |
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Abstract |
This paper focuses on how the production and polarization of gravitational waves are affected by spontaneous Lorentz symmetry breaking, which is driven by a self-interacting vector field. Specifically, we examine the impact of a smooth quadratic potential and a non-minimal coupling, discussing the constraints and causality features of the linearized Einstein equation. To analyze the polarization states of a plane wave, we consider a fixed vacuum expectation value (VEV) of the vector field. Remarkably, we verify that a space-like background vector field modifies the polarization plane and introduces a longitudinal degree of freedom. In order to investigate the Lorentz violation effect on the quadrupole formula, we use the modified Green function. Finally, we show that the space-like component of the background field leads to a third-order time derivative of the quadrupole moment, and the bounds for the Lorentz-breaking coefficients are estimated as well. |
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Address |
[Amarilo, K. M.; Ferreira Filho, M. B.] Univ Estado Rio de Janeiro, Dep Fis Nucl & Altas Energias, Inst Fis, Rua Sao Francisco Xavier 524, BR-20559900 Rio De Janeiro, RJ, Brazil, Email: kevin.amarilo@cern.ch; |
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Elsevier |
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English |
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ISSN |
0370-2693 |
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Notes |
WOS:001257664300001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
6168 |
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Author |
LHCb Collaboration (Aaij, R. et al); Henry, L.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
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Title |
Search for long-lived particles decaying to e(+/-)mu(-/+)nu |
Type |
Journal Article |
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Year |
2021 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
81 |
Issue |
3 |
Pages |
261 - 16pp |
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Keywords |
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Abstract |
Long-lived particles decaying to e(+/-) mu(-/+)nu, with masses between 7 and 50 GeV/c(2) and lifetimes between 2 and 50 ps, are searched for by looking at displaced vertices containing electrons and muons of opposite charges. The search is performed using 5.4 fb(-1) of pp collisions collected with the LHCb detector at a centre-of-mass energy of root s = 13 TeV. Three mechanisms of production of long-lived particles are considered: the direct pair production from quark interactions, the pair production from the decay of a Standard-Model-like Higgs boson with a mass of 125 GeV/c(2), and the charged current production from an on-shell W boson with an additional lepton. No evidence of these long-lived states is obtained and upper limits on the production cross-section times branching fraction are set on the different production modes. |
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Address |
[Amato, S.; De Paula, L.; Rodrigues, F. Ferreira; Gandelman, M.; Hicheur, A.; Lopes, J. H.; Garcia, L. Meyer; Nasteva, I; Goicochea, J. M. Otalora; Polycarpo, E.; Rangel, M. S.; De Almeida, F. L. Souza; De Paula, B. Souza] Univ Fed Rio de Janeiro UFRJ, Rio De Janeiro, Brazil, Email: matthieu.marinangeli@gmail.com |
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Thesis |
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Publisher |
Springer |
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 |
1434-6044 |
ISBN |
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Conference |
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Notes |
WOS:000634800600002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4771 |
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Author |
Gomez Ambrosio, R.; ter Hoeve, J.; Madigan, M.; Rojo, J.; Sanz, V. |
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Title |
Unbinned multivariate observables for global SMEFT analyses from machine learning |
Type |
Journal Article |
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Year |
2023 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
033 - 66pp |
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Keywords |
SMEFT; Higgs Properties |
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Abstract |
Theoretical interpretations of particle physics data, such as the determination of the Wilson coefficients of the Standard Model Effective Field Theory (SMEFT), often involve the inference of multiple parameters from a global dataset. Optimizing such interpretations requires the identification of observables that exhibit the highest possible sensitivity to the underlying theory parameters. In this work we develop a flexible open source frame-work, ML4EFT, enabling the integration of unbinned multivariate observables into global SMEFT fits. As compared to traditional measurements, such observables enhance the sensitivity to the theory parameters by preventing the information loss incurred when binning in a subset of final-state kinematic variables. Our strategy combines machine learning regression and classification techniques to parameterize high-dimensional likelihood ratios, using the Monte Carlo replica method to estimate and propagate methodological uncertainties. As a proof of concept we construct unbinned multivariate observables for top-quark pair and Higgs+Z production at the LHC, demonstrate their impact on the SMEFT parameter space as compared to binned measurements, and study the improved constraints associated to multivariate inputs. Since the number of neural networks to be trained scales quadratically with the number of parameters and can be fully parallelized, the ML4EFT framework is well-suited to construct unbinned multivariate observables which depend on up to tens of EFT coefficients, as required in global fits. |
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Address |
[Ambrosio, Raquel Gomez] Univ Milano Bicocca, Dipartimento Fis G Occhialini, Piazza Sci 3, I-20126 Milan, Italy, Email: raquel.gomezambrosio@unito.it; |
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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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Edition |
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ISSN |
1029-8479 |
ISBN |
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Area |
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Conference |
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Notes |
WOS:000946004000003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5501 |
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Author |
Amerio, A.; Cuoco, A.; Fornengo, N. |
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Title |
Extracting the gamma-ray source-count distribution below the Fermi-LAT detection limit with deep learning |
Type |
Journal Article |
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Year |
2023 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
09 |
Issue |
9 |
Pages |
029 - 39pp |
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Keywords |
gamma ray theory; Machine learning |
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Abstract |
We reconstruct the extra-galactic gamma-ray source-count distribution, or dN/dS, of resolved and unresolved sources by adopting machine learning techniques. Specifically, we train a convolutional neural network on synthetic 2-dimensional sky-maps, which are built by varying parameters of underlying source-counts models and incorporate the FermiLAT instrumental response functions. The trained neural network is then applied to the Fermi-LAT data, from which we estimate the source count distribution down to flux levels a factor of 50 below the Fermi-LAT threshold. We perform our analysis using 14 years of data collected in the (1, 10) GeV energy range. The results we obtain show a source count distribution which, in the resolved regime, is in excellent agreement with the one derived from cataloged sources, and then extends as dN/dS " S-2 in the unresolved regime, down to fluxes of 5 center dot 10-12 cm-2 s-1. The neural network architecture and the devised methodology have the flexibility to enable future analyses to study the energy dependence of the source-count distribution. |
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Address |
[Amerio, A.] Univ Valencia, Inst Fis Corpuscular IFIC, Calle Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: aurelio.amerio@ific.uv.es; |
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Corporate Author |
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Thesis |
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Publisher |
IOP Publishing Ltd |
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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Edition |
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ISSN |
1475-7516 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001097055700001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5785 |
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