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Author |
Kasieczka, G. et al; Sanz, V. |
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Title |
The LHC Olympics 2020: a community challenge for anomaly detection in high energy physics |
Type |
Journal Article |
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Year |
2021 |
Publication |
Reports on Progress in Physics |
Abbreviated Journal |
Rep. Prog. Phys. |
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Volume  |
84 |
Issue |
12 |
Pages |
124201 - 64pp |
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Keywords |
anomaly detection; machine learning; unsupervised learning; weakly supervised learning; semisupervised learning; beyond the standard model; model-agnostic methods |
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Abstract |
A new paradigm for data-driven, model-agnostic new physics searches at colliders is emerging, and aims to leverage recent breakthroughs in anomaly detection and machine learning. In order to develop and benchmark new anomaly detection methods within this framework, it is essential to have standard datasets. To this end, we have created the LHC Olympics 2020, a community challenge accompanied by a set of simulated collider events. Participants in these Olympics have developed their methods using an R&D dataset and then tested them on black boxes: datasets with an unknown anomaly (or not). Methods made use of modern machine learning tools and were based on unsupervised learning (autoencoders, generative adversarial networks, normalizing flows), weakly supervised learning, and semi-supervised learning. This paper will review the LHC Olympics 2020 challenge, including an overview of the competition, a description of methods deployed in the competition, lessons learned from the experience, and implications for data analyses with future datasets as well as future colliders. |
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Address |
[Kasieczka, Gregor] Univ Hamburg, Inst Expt Phys, Hamburg, Germany, Email: gregor.kasieczka@uni-hamburg.de; |
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Publisher |
IOP Publishing Ltd |
Place of Publication |
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Language |
English |
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Original 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 |
0034-4885 |
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Conference |
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Notes |
WOS:000727698500001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5039 |
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Author |
Pajtler, M.V. et al; Gadea, A. |
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Title |
Excited states of Y-90,Y-92,Y-94 populated in Zr-90+Pb-208 multinucleon transfer reaction |
Type |
Journal Article |
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Year |
2021 |
Publication |
Physica Scripta |
Abbreviated Journal |
Phys. Scr. |
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Volume |
96 |
Issue |
3 |
Pages |
035305 - 7pp |
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Keywords |
multinucleon transfer reactions; gamma spectroscopy; magnetic spectrometers; gamma-ray spectrometers |
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Abstract |
Multinucleon transfer reactions in Zr-90+Pb-208 have been studied via fragment-gamma coincidences, employing the PRISMA magnetic spectrometer coupled to the CLARA gamma-array. An analysis on Y isotopes has been carried out incorporating spectroscopic as well as reaction mechanism aspects. New gamma transitions have been observed in Y-94, confirming the findings of recent studies where nuclei were produced via fission of uranium, and a comparison with near-by Y-90,Y-92 isotopes populated in the same reaction has been discussed. Experimental cross sections have been extracted and compared with the GRAZING calculations, showing a fair agreement along the neutron pick-up side. The results confirm how multinucleon transfer reactions are a suitable mechanism for the study of neutron-rich nuclei. |
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Address |
[Pajtler, M. Varga] Univ Osijek, Dept Phys, Osijek, Croatia, Email: Suzana.Szilner@irb.hr; |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Language |
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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Series Issue |
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Edition |
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ISSN |
0031-8949 |
ISBN |
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Conference |
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Notes |
WOS:000611517400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4694 |
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Author |
IDS Collaboration (Piersa-Silkowska, M. et al); Nacher, E. |
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Title |
First beta-decay spectroscopy of In-135 and new beta-decay branches of In-134 |
Type |
Journal Article |
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Year |
2021 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
101 |
Issue |
4 |
Pages |
044328 - 19pp |
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Keywords |
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Abstract |
The beta decay of the neutron-rich In-134 and In-135 was investigated experimentally in order to provide new insights into the nuclear structure of the tin isotopes with magic proton number Z = 50 above the N = 82 shell. The beta-delayed gamma-ray spectroscopy measurement was performed at the ISOLDE facility at CERN, where indium isotopes were selectively laser-ionized and on-line mass separated. Three beta-decay branches of In-134 were established, two of which were observed for the first time. Population of neutron-unbound states decaying via gamma rays was identified in the two daughter nuclei of In-134, Sn-134 and Sn-133, at excitation energies exceeding the neutron separation energy by 1 MeV. The beta-delayed one-and two-neutron emission branching ratios of In-134 were determined and compared with theoretical calculations. The beta-delayed one-neutron decay was observed to be dominant beta-decay branch of In-134 even though the Gamow-Teller resonance is located substantially above the two-neutron separation energy of Sn-134. Transitions following the beta decay of In-135 are reported for the first time, including gamma rays tentatively attributed to Sn-135. In total, six new levels were identified in Sn-134 on the basis of the beta gamma gamma coincidences observed in the In-134 and In-135 beta decays. A transition that might be a candidate for deexciting the missing neutron single-particle 13/2(+) state in Sn-133 was observed in both beta decays and its assignment is discussed. Experimental level schemes of Sn-134 and Sn-135 are compared with shell-model predictions. Using the fast timing technique, half-lives of the 2(+), 4(+), and 6(+) levels in Sn-134 were determined. From the lifetime of the 4(+) state measured for the first time, an unexpectedly large B(E2; 4(+) -> 2(+)) transition strength was deduced, which is not reproduced by the shell-model calculations. |
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Address |
[Piersa-Silkowska, M.; Korgul, A.; Adamska, E.; Fijalkowska, A.; Janas, Z.; Kicinska-Habior, M.; Koszuk, L.; Mazzocchi, C.; Miernik, K.; Silkowski, M.; Stryjczyk, M.] Univ Warsaw, Fac Phys, PL-02093 Warsaw, Poland, Email: monika.piersa@cern.ch; |
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Corporate Author |
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Thesis |
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Publisher |
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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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 |
2469-9985 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000712038200001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5014 |
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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 |
Observation of a new Xi(0)(b) state |
Type |
Journal Article |
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Year |
2021 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
103 |
Issue |
1 |
Pages |
012004 - 17pp |
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Keywords |
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Abstract |
Using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of 8.5 fb(-1), the observation of a new excited Xi(0)(b) resonance decaying to the Xi(-)(b)pi(+) final state is presented. The state, referred to as Xi(b) (6227)(0), has a measured mass and natural width of m(Xi(b)(6227)(0)) = 6227.1(-1.5)(+1.4) +/- 0.5 MeV and Gamma(Xi(b)(6227)(0)) = 18.6(-4.1)(+5.0) +/- 1.4 MeV, where the uncertainties are statistical and systematic. The production rate of the Xi(b)(6227)(0) state relative to that of the Xi(-)(b) baryon in the kinematic region 2 < eta < 5 and p(T) < 30 GeV is measured to be f(Xi b(6227)0)/f(Xi b)(-) B(Xi(b)(6227)(0) -> Xi(-)(b)pi(+)) = 0.045 +/- 0.008 +/- 0.004, where B(Xi(b)(6227)(0) -> Xi(-)(b)pi(+)) is the branching fraction of the decay, and f(Xi b(6227)0) and f(Xi b-) represent fragmentation fractions. Improved measurements of the mass and natural width of the previously observedf Xi(b)(6227)(-) state, along with the mass of the Xi(-)(b) baryon, are also reported. Both measurements are significantly more precise than, and consistent with, previously reported values. |
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Address |
[Leite, J. Baptista; Bediaga, I; Torres, M. Cruz; De Miranda, J. M.; dos Reis, A. C.; Gomes, A.; Massafferri, A.; Machado, D. Torres] Ctr Brasileiro Pesquisas Fis CBPF, Rio De Janeiro, Brazil |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
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 |
2470-0010 |
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 |
WOS:000605120700001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4684 |
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| Permanent link to this record |
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Author |
Linster, M.; Lopez-Pavon, J.; Ziegler, R. |
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Title |
Neutrino observables from a U(2) flavor symmetry |
Type |
Journal Article |
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Year |
2021 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
103 |
Issue |
1 |
Pages |
015020 - 9pp |
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Keywords |
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Abstract |
We study the predictions for CP phases and absolute neutrino mass scale for broad classes of models with a U(2)-like flavor symmetry. For this purpose we consider the same special textures in neutrino and charged lepton mass matrices that are successful in the quark sector. While in the neutrino sector the U(2) structure enforces two texture zeros, the contribution of the charged lepton sector to the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix can be parametrized by two rotation angles. Restricting to the cases where at least one of these angles is small, we obtain three representative scenarios. In all scenarios we obtain a narrow prediction for the sum of neutrino masses in the range of 60-75 meV, possibly in the reach of upcoming galaxy survey experiments. All scenarios can be excluded if near-future experimental date provide evidence for either neutrinoless double-beta decay or inverted neutrino mass ordering. |
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Address |
[Linster, Matthias; Ziegler, Robert] Karlsruhe Inst Technol, Inst Theoret Teilchenphys, D-76131 Karlsruhe, Germany |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
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 |
2470-0010 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000609014300006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4689 |
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