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Author |
Gammaldi, V.; Zaldivar, B.; Sanchez-Conde, M.A.; Coronado-Blazquez, J. |
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Title |
A search for dark matter among Fermi-LAT unidentified sources with systematic features in machine learning |
Type |
Journal Article |
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Year |
2023 |
Publication |
Monthly Notices of the Royal Astronomical Society |
Abbreviated Journal |
Mon. Not. Roy. Astron. Soc. |
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Volume |
520 |
Issue |
1 |
Pages |
1348-1361 |
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Keywords |
astroparticle physics – methods; data analysis – methods; observational – methods; statistical – dark matter – gamma-rays; general |
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Abstract |
Around one-third of the point-like sources in the Fermi-LAT catalogues remain as unidentified sources (unIDs) today. Indeed, these unIDs lack a clear, univocal association with a known astrophysical source. If dark matter (DM) is composed of weakly interacting massive particles (WIMPs), there is the exciting possibility that some of these unIDs may actually be DM sources, emitting gamma-rays from WIMPs annihilation. We propose a new approach to solve the standard, machine learning (ML) binary classification problem of disentangling prospective DM sources (simulated data) from astrophysical sources (observed data) among the unIDs of the 4FGL Fermi-LAT catalogue. We artificially build two systematic features for the DM data which are originally inherent to observed data: the detection significance and the uncertainty on the spectral curvature. We do it by sampling from the observed population of unIDs, assuming that the DM distributions would, if any, follow the latter. We consider different ML models: Logistic Regression, Neural Network (NN), Naive Bayes, and Gaussian Process, out of which the best, in terms of classification accuracy, is the NN, achieving around 93 . 3 per cent +/- 0 . 7 per cent performance. Other ML evaluation parameters, such as the True Ne gativ e and True Positive rates, are discussed in our work. Applying the NN to the unIDs sample, we find that the de generac y between some astrophysical and DM sources can be partially solved within this methodology. None the less, we conclude that there are no DM source candidates among the pool of 4FGL Fermi-LAT unIDs. |
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Address  |
[Gammaldi, V; Sanchez-Conde, M. A.; Coronado-Blazquez, J.] Univ Autonoma Madrid, Departamentode Fis Teor, E-28049 Madrid, Spain, Email: viviana.gammaldi@uam.es; |
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Publisher |
Oxford Univ Press |
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English |
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ISSN |
0035-8711 |
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Notes |
WOS:000937053400014 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
5489 |
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Author |
Abele, H. et al; Algora, A.; Gonzalez-Alonso, M.; Novella, P. |
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Title |
Particle physics at the European Spallation Source |
Type |
Journal Article |
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Year |
2023 |
Publication |
Physics Reports |
Abbreviated Journal |
Phys. Rep. |
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Volume |
1023 |
Issue |
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Pages |
1-84 |
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Keywords |
ESS; Neutrons; NNBAR; ESSnuSB; nEDM |
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Abstract |
Presently under construction in Lund, Sweden, the European Spallation Source (ESS) will be the world's brightest neutron source. As such, it has the potential for a particle physics program with a unique reach and which is complementary to that available at other facilities. This paper describes proposed particle physics activities for the ESS. These encompass the exploitation of both the neutrons and neutrinos produced at the ESS for high precision (sensitivity) measurements (searches). |
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Address |
[Fynbo, H. O. U.; Uggerhoj, U. I.] Aarhus Univ, Dept Phys & Astron, Aarhus, Denmark, Email: milstead@fysik.su.se |
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Publisher |
Elsevier |
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English |
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ISSN |
0370-1573 |
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Conference |
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Notes |
WOS:001063474900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5685 |
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Author |
Fougeres, C. et al; Domingo-Pardo, C. |
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Title |
Search for Na-22 in novae supported by a novel method for measuring femtosecond nuclear lifetimes |
Type |
Journal Article |
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Year |
2023 |
Publication |
Nature Communications |
Abbreviated Journal |
Nat. Commun. |
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Volume |
14 |
Issue |
1 |
Pages |
4536 - 7pp |
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Keywords |
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Abstract |
Classical novae are thermonuclear explosions in stellar binary systems, and important sources of Al-26 and Na-22. While ? rays from the decay of the former radioisotope have been observed throughout the Galaxy, Na-22 remains untraceable. Its half-life (2.6 yr) would allow the observation of its 1.275 MeV ?-ray line from a cosmic source. However, the prediction of such an observation requires good knowledge of its nucleosynthesis. The Na-22(p, ?)Mg-23 reaction remains the only source of large uncertainty about the amount of Na-22 ejected. Its rate is dominated by a single resonance on the short-lived state at 7785.0(7) keV in Mg-23. Here, we propose a combined analysis of particle-particle correlations and velocity-difference profiles to measure femtosecond nuclear lifetimes. The application of this method to the study of the Mg-23 states, places strong limits on the amount of Na-22 produced in novae and constrains its detectability with future space-borne observatories. The authors report a particle-particle correlation and velocity-difference profile method to measure nuclear lifetime. The results obtained for excited states of 23Mg are used to constrain the production of 22Na in the astrophysical novae explosions. |
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Address |
[Fougeres, Chloe; Santos, Francois de Oliveira; Michelagnoli, Caterina; Clement, Emmanuel; Kim, Yung Hee; Lemasson, Antoine; Boulay, Florent; Goupil, Johan; Li, Hongjie; Navin, Alahari; Ralet, Damien; Saillant, Frederic] Grand Accelerateur Natl Ions Lourds GANIL, CEA, IN2P3, DRF CNRS, Caen, France, Email: chloe.fougeres@gmail.com; |
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Publisher |
Nature Portfolio |
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Language |
English |
Summary Language |
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Notes |
WOS:001063751200012 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5671 |
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Author |
Forconi, M.; Ruchika; Melchiorri, A.; Mena, O.; Menci, N. |
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Title |
Do the early galaxies observed by JWST disagree with Planck's CMB polarization measurements? |
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 |
10 |
Issue |
10 |
Pages |
012 - 16pp |
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Keywords |
cosmological parameters from CMBR; high redshift galaxies; CMBR polarisation; reionization |
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Abstract |
The recent observations from the James Webb Space Telescope have led to a surprising discovery of a significant density of massive galaxies with masses of M >= 10(10.5)M(circle dot) at redshifts of approximately z similar to 10. This corresponds to a stellar mass density of roughly rho* similar to 10(6)M(circle dot) Mpc(-3). Despite making conservative assumptions regarding galaxy formation, this finding may not be compatible with the standard.CDM cosmology that is favored by observations of CMB Anisotropies from the Planck satellite. In this paper, we confirm the substantial discrepancy with Planck's results within the.CDM framework. Assuming a value of is an element of = 0.2 for the efficiency of converting baryons into stars, we indeed find that the.CDM model is excluded at more than 99.7% confidence level (C.L.). An even more significant exclusion is found for is an element of similar to 0.1, while a better agreement, but still in tension at more than 95%, is obtained for is an element of = 0.32. This tension, as already discussed in the literature, could arise either from systematics in the JWST measurements or from new physics. Here, as a last-ditch effort, we point out that disregarding the large angular scale polarization obtained by Planck, which allows for significantly larger values of the matter clustering parameter sigma(8), could lead to better agreement between Planck and JWST within the.CDM framework. Assuming.CDM and no systematics in the current JWST results, this implies either an unknown systematic error in current large angular scale CMB polarization measurements or an unidentified physical mechanism that could lower the expected amount of CMB polarization produced during the epoch of reionization. Interestingly, the model compatible with Planck temperature-only data and JWST observation also favors a higher Hubble constant H-0 = 69.0 +/- 1.1 km/s/Mpc at 68% C.L., in better agreement with observations based on SN-Ia luminosity distances. |
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Address |
[Forconi, Matteo; Ruchika; Melchiorri, Alessandro] Univ Roma La Sapienza, Phys Dept, Ple Aldo Moro 2, I-00185 Rome, Italy, Email: matteo.forconi@roma1.infn.it; |
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Publisher |
IOP Publishing Ltd |
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English |
Summary Language |
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Series Issue |
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Edition |
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ISSN |
1475-7516 |
ISBN |
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Notes |
WOS:001142721200001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5903 |
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Author |
Flores, M.M.; Kim, J.S.; Rolbiecki, K.; Ruiz de Austri, R. |
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Title |
Updated LHC bounds on MUED after run 2 |
Type |
Journal Article |
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Year |
2023 |
Publication |
International Journal of Modern Physics A |
Abbreviated Journal |
Int. J. Mod. Phys. A |
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Volume |
38 |
Issue |
1 |
Pages |
2350002 - 14pp |
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Keywords |
Universal extra dimensions; large hadron collider; phenomenology |
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Abstract |
We present updated LHC limits on the minimal universal extra dimensions (MUEDs) model from the Run 2 searches. We scan the parameter space against a number of searches implemented in the public code CheckMATE and derive up-to-date limits on the MUED parameter space from 13TeV searches. The strongest constraints come from a search dedicated to squarks and gluinos with one isolated lepton, jets and missing transverse energy. In the procedure, we take into account initial state radiation and stress its importance in the MUED searches, which is not always appreciated. |
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Address |
[Flores, Marvin M.] Univ Philippines, Natl Inst Phys, Diliman, Quezon City, Philippines, Email: mflores@nip.upd.edu.ph |
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Corporate Author |
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Publisher |
World Scientific Publ Co Pte 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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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 |
0217-751x |
ISBN |
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Conference |
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Notes |
WOS:000936994000001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5487 |
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