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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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IOP Publishing Ltd |
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English |
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ISSN |
0034-4885 |
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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 |
Monerris-Belda, O.; Cervera Marin, R.; Rodriguez Jodar, M.; Diaz-Caballero, E.; Alcaide Guillen, C.; Petit, J.; Boria, V.E.; Gimeno, B.; Raboso, D. |
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Title |
High Power RF Discharge Detection Technique Based on the In-Phase and Quadrature Signals |
Type |
Journal Article |
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Year |
2021 |
Publication |
IEEE Transactions on Microwave Theory and Techniques |
Abbreviated Journal |
IEEE Trans. Microw. Theory Tech. |
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Volume |
69 |
Issue |
12 |
Pages |
5429-5438 |
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Keywords |
Radio frequency; Microwave theory and techniques; Electric breakdown; Discharges (electric); Noise measurement; Sensitivity; RF signals; Corona; microwave devices; multipactor; radio frequency (RF) breakdown; RF high power |
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Abstract |
High power radio frequency (RF) breakdown testing is a subject of great relevance in the space industry, due to the increasing need of higher transmission power and smaller devices. This work presents a novel RF breakdown detection system, which monitors the same parameters as the microwave nulling system but with several advantages. Where microwave nulling-a de facto standard in RF breakdown testing-is narrowband and requires continuous tuning to keep its sensitivity, the proposed technique is broadband and maintains its performance for any RF signal. On top of that, defining the detection threshold is cumbersome due to the lack of an international standardized criterion. Small responses may appear in the detection system during the test and, sometimes, it is not possible to determine if these are an actual RF breakdown or random noise. This new detection system uses a larger analysis bandwidth, thus reducing the cases in which a small response is difficult to be classified. The proposed detection method represents a major step forward in high power testing as it runs without human intervention, warning the operator or decreasing the RF power automatically much faster than any human operator. |
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Address |
[Monerris-Belda, Oscar; Cervera Marin, Raul; Rodriguez Jodar, Miguel; Petit, John] Val Space Consortium, Valencia 46022, Spain, Email: oscar.monerris@val-space.com |
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Ieee-Inst Electrical Electronics Engineers Inc |
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English |
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ISSN |
0018-9480 |
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Notes |
WOS:000725804500027 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5042 |
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Author |
Barenboim, G.; Blinov, N.; Stebbins, A. |
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Title |
Smallest remnants of early matter domination |
Type |
Journal Article |
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Year |
2021 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
12 |
Issue |
12 |
Pages |
026 - 50pp |
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Keywords |
cosmology of theories beyond the SM; physics of the early universe; cosmological perturbation theory |
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Abstract |
The evolution of the universe prior to Big Bang Nucleosynthesis could have gone through a phase of early matter domination which enhanced the growth of small-scale dark matter structure. If this period was long enough, self-gravitating objects formed prior to reheating. We study the evolution of these dense early halos through reheating. At the end of early matter domination, the early halos undergo rapid expansion and eventually eject their matter. We find that this process washes out structure on scales much larger than naively expected from the size of the original halos. We compute the density profiles of the early halo remnants and use them to construct late-time power spectra that include these non-linear effects. We evolve the resulting power spectrum to estimate the properties of microhalos that would form after matter-radiation equality. Surprisingly, cosmologies with a short period of early matter domination lead to an earlier onset of microhalo formation compared to those with a long period. In either case, dark matter structure formation begins much earlier than in the standard cosmology, with most dark matter bound in microhalos in the late universe. |
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Address |
[Barenboim, Gabriela] Univ Valencia, Dept Fis Teor, CSIC, E-46100 Burjassot, Spain, Email: Gabriela.Barenboim@uv.es; |
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Publisher |
IOP Publishing Ltd |
Place of Publication |
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English |
Summary Language |
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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 |
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:000734341100008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5060 |
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Author |
Garani, R.; Gasparotto, F.; Mastrolia, P.; Munch, H.J.; Palomares-Ruiz, S.; Primo, A. |
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Title |
Two-photon exchange in leptophilic dark matter scenarios |
Type |
Journal Article |
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Year |
2021 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
12 |
Issue |
12 |
Pages |
212 - 42pp |
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Keywords |
Cosmology of Theories beyond the SM; Effective Field Theories; Integrable Hierarchies |
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Abstract |
In leptophilic scenarios, dark matter interactions with nuclei, relevant for direct detection experiments and for the capture by celestial objects, could only occur via loop-induced processes. If the mediator is a scalar or pseudo-scalar particle, which only couples to leptons, the dominant contribution to dark matter-nucleus scattering would take place via two-photon exchange with a lepton triangle loop. The corresponding diagrams have been estimated in the literature under different approximations. Here, we present new analytical calculations for one-body two-loop and two-body one-loop interactions. The two-loop form factors are presented in closed analytical form in terms of generalized polylogarithms up to weight four. In both cases, we consider the exact dependence on all the involved scales, and study the dependence on the momentum transfer. We show that some previous approximations fail to correctly predict the scattering cross section by several orders of magnitude. Moreover, we quantitatively show that form factors in the range of momentum transfer relevant for local galactic dark matter, can be significantly smaller than their value at zero momentum transfer, which is the approach usually considered. |
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Address |
[Garani, Raghuveer] Ist Nazl Fis Nucl, Sez Firenze, Via G Sansone 1, I-50019 Sesto Fiorentino, Italy, Email: garani@fi.infn.it; |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
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Language |
English |
Summary Language |
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Abbreviated Series Title |
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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:000736468500004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5068 |
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Author |
Moretti, F.; Bombacigno, F.; Montani, G. |
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Title |
The Role of Longitudinal Polarizations in Horndeski and Macroscopic Gravity: Introducing Gravitational Plasmas |
Type |
Journal Article |
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Year |
2021 |
Publication |
Universe |
Abbreviated Journal |
Universe |
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Volume |
7 |
Issue |
12 |
Pages |
496 - 28pp |
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Keywords |
gravitational waves; gauge-invariant method; Landau damping; macroscopic gravity |
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Abstract |
We discuss some general and relevant features of longitudinal gravitational modes in Horndeski gravity and their interaction with matter media. Adopting a gauge-invariant formulation, we clarify how massive scalar and vector fields can induce additional transverse and longitudinal excitations, resulting in breathing, vector, and longitudinal polarizations. We review, then, the interaction of standard gravitational waves with a molecular medium, outlining the emergence of effective massive gravitons, induced by the net quadrupole moment due to molecule deformation. Finally, we investigate the interaction of the massive mode in Horndeski gravity with a noncollisional medium, showing that Landau damping phenomenon can occur in the gravitational sector as well. That allows us to introduce the concept of “gravitational plasma”, where inertial forces associated with the background field play the role of cold ions in electromagnetic plasma. |
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Address |
[Moretti, Fabio; Montani, Giovanni] Sapienza Univ Rome, Dept Phys, Ple Aldo Moro 5, I-00185 Rome, Italy, Email: fabio.moretti@uniroma1.it; |
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Publisher |
Mdpi |
Place of Publication |
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English |
Summary Language |
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Series Editor |
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Conference |
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Notes |
WOS:000741918900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5076 |
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Author |
Araujo Filho, A.A. |
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Title |
Thermodynamics of massless particles in curved spacetime |
Type |
Journal Article |
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Year |
2023 |
Publication |
International Journal of Geometric Methods in Modern Physics |
Abbreviated Journal |
Int. J. Geom. Methods Mod. Phys. |
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Volume |
12 |
Issue |
13 |
Pages |
2350226 - 40pp |
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Keywords |
Einstein-aether; thermodynamic properties; curved spacetime |
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Abstract |
This work is devoted to study the behavior of massless particles within the context of curved spacetime. In essence, we investigate the consequences of the scale factor C(?) of the Friedmann-Robertson-Walker metric in the Einstein-aether formalism to study photon-like particles. To do so, we consider the system within the canonical ensemble formalism in order to derive the following thermodynamic state quantities: spectral radiance, Helmholtz free energy, pressure, entropy, mean energy and the heat capacity. Moreover, the correction to the Stefan-Boltzmann law and the equation of states are also provided. Particularly, we separate our study within three distinct cases, i.e. s = 0, p = 0; s = 1, p = 1; s = 2, p = 1. In the first one, the results are derived numerically. Nevertheless, for the rest of the cases, all the calculations are accomplished analytically showing explicitly the dependence of the scale factor C(?) and the Riemann zeta function ?(s). Furthermore, our analyses are accomplished in general taking into account three different regimes of temperature of the universe, i.e. the inflationary era (T = 10(13)GeV), the electroweak epoch (T = 10(3)GeV) and the cosmic microwave background (T = 10(-13)GeV). |
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Address |
[Araujo Filho, A. A.] Univ Fed Cearra UFC, Dept Fis, Campus Pici,CP 6030, BR-60455760 Fortaleza, CE, Brazil, Email: dilto@fisica.ufc.br |
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Publisher |
World Scientific Publ Co Pte Ltd |
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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 |
0219-8878 |
ISBN |
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Conference |
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Notes |
WOS:001048378900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5613 |
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Author |
Di Gregorio, E.; Staelens, M.; Hosseinkhah, N.; Karimpoor, M.; Liburd, J.; Lim, L.; Shankar, K.; Tuszynski, J.A. |
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Title |
Raman Spectroscopy Reveals Photobiomodulation-Induced α-Helix to β-Sheet Transition in Tubulins: Potential Implications for Alzheimer's and Other Neurodegenerative Diseases |
Type |
Journal Article |
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Year |
2024 |
Publication |
Nanomaterials |
Abbreviated Journal |
Nanomaterials |
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Volume |
14 |
Issue |
13 |
Pages |
1093 - 21pp |
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Keywords |
proteins; protein dynamics; protein structure; non-invasive therapies; low-level laser therapy; spectroscopy; amide bands; amide I; spectral decomposition |
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Abstract |
In small clinical studies, the application of transcranial photobiomodulation (PBM), which typically delivers low-intensity near-infrared (NIR) to treat the brain, has led to some remarkable results in the treatment of dementia and several neurodegenerative diseases. However, despite the extensive literature detailing the mechanisms of action underlying PBM outcomes, the specific mechanisms affecting neurodegenerative diseases are not entirely clear. While large clinical trials are warranted to validate these findings, evidence of the mechanisms can explain and thus provide credible support for PBM as a potential treatment for these diseases. Tubulin and its polymerized state of microtubules have been known to play important roles in the pathology of Alzheimer's and other neurodegenerative diseases. Thus, we investigated the effects of PBM on these cellular structures in the quest for insights into the underlying therapeutic mechanisms. In this study, we employed a Raman spectroscopic analysis of the amide I band of polymerized samples of tubulin exposed to pulsed low-intensity NIR radiation (810 nm, 10 Hz, 22.5 J/cm2 dose). Peaks in the Raman fingerprint region (300-1900 cm-1)-in particular, in the amide I band (1600-1700 cm-1)-were used to quantify the percentage of protein secondary structures. Under this band, hidden signals of C=O stretching, belonging to different structures, are superimposed, producing a complex signal as a result. An accurate decomposition of the amide I band is therefore required for the reliable analysis of the conformation of proteins, which we achieved through a straightforward method employing a Voigt profile. This approach was validated through secondary structure analyses of unexposed control samples, for which comparisons with other values available in the literature could be conducted. Subsequently, using this validated method, we present novel findings of statistically significant alterations in the secondary structures of polymerized NIR-exposed tubulin, characterized by a notable decrease in alpha-helix content and a concurrent increase in beta-sheets compared to the control samples. This PBM-induced alpha-helix to beta-sheet transition connects to reduced microtubule stability and the introduction of dynamism to allow for the remodeling and, consequently, refreshing of microtubule structures. This newly discovered mechanism could have implications for reducing the risks associated with brain aging, including neurodegenerative diseases like Alzheimer's disease, through the introduction of an intervention following this transition. |
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Address |
[Di Gregorio, Elisabetta; Staelens, Michael; Tuszynski, Jack A.] Univ Alberta, Fac Sci, Dept Phys, Edmonton, AB T6G 2E1, Canada, Email: michael.staelens@ific.uv.es |
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Mdpi |
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English |
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Expedition |
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Conference |
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Notes |
WOS:001269841000001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
6204 |
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Author |
Hueso-Gonzalez, F.; Vijande, J.; Ballester, F.; Perez-Calatayud, J.; Siebert, F.A. |
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Title |
A simple analytical method for heterogeneity corrections in low dose rate prostate brachytherapy |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physics in Medicine and Biology |
Abbreviated Journal |
Phys. Med. Biol. |
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Volume |
60 |
Issue |
14 |
Pages |
5455-5469 |
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Keywords |
brachytherapy; low dose rate; heterogeneities; prostate; calcifications |
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Abstract |
In low energy brachytherapy, the presence of tissue heterogeneities contributes significantly to the discrepancies observed between treatment plan and delivered dose. In this work, we present a simplified analytical dose calculation algorithm for heterogeneous tissue. We compare it with Monte Carlo computations and assess its suitability for integration in clinical treatment planning systems. The algorithm, named as RayStretch, is based on the classic equivalent path length method and TG-43 reference data. Analytical and Monte Carlo dose calculations using Penelope2008 are compared for a benchmark case: a prostate patient with calcifications. The results show a remarkable agreement between simulation and algorithm, the latter having, in addition, a high calculation speed. The proposed analytical model is compatible with clinical real-time treatment planning systems based on TG-43 consensus datasets for improving dose calculation and treatment quality in heterogeneous tissue. Moreover, the algorithm is applicable for any type of heterogeneities. |
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Address |
[Hueso-Gonzalez, Fernando; Vijande, Javier; Ballester, Facundo] Univ Valencia, Dept Atom Mol & Nucl Phys, E-46100 Burjassot, Spain, Email: Javier.Vijande@uv.es |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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English |
Summary Language |
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Abbreviated Series Title |
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ISSN |
0031-9155 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000357620400009 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2296 |
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Author |
Solevi, P.; Muñoz, E.; Solaz, C.; Trovato, M.; Dendooven, P.; Gillam, J.E.; Lacasta, C.; Oliver, J.F.; Rafecas, M.; Torres-Espallardo, I.; Llosa, G. |
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Title |
Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams |
Type |
Journal Article |
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Year |
2016 |
Publication |
Physics in Medicine and Biology |
Abbreviated Journal |
Phys. Med. Biol. |
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Volume |
61 |
Issue |
14 |
Pages |
5149-5165 |
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Keywords |
ion-beam therapy; range verification; prompt gamma; Compton camera; GATE |
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Abstract |
In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing Na-22 and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3-5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy. |
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Address |
[Solevi, Paola; Munoz, Enrique; Solaz, Carles; Trovato, Marco; Gillam, John E.; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosa, Gabriela] IFIC CSIC UVEG, Inst Fis Corpuscular, Valencia, Spain, Email: paola.solevi@ovgu.de |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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English |
Summary Language |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9155 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000379555300007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2754 |
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Author |
Roser, J.; Muñoz, E.; Barrientos, L.; Barrio, J.; Bernabeu, J.; Borja-Lloret, M.; Etxebeste, A.; Llosa, G.; Ros, A.; Viegas, R.; Oliver, J.F. |
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Title |
Image reconstruction for a multi-layer Compton telescope: an analytical model for three interaction events |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physics in Medicine and Biology |
Abbreviated Journal |
Phys. Med. Biol. |
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Volume |
65 |
Issue |
14 |
Pages |
145005 - 17pp |
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Keywords |
Compton camera; Compton imaging; hadron therapy; image reconstruction; lm-mlem; monte carlo simulations; multi-layer Compton telescope |
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Abstract |
Compton Cameras are electronically collimated photon imagers suitable for sub-MeV to few MeV gamma-ray detection. Such features are desirable to enablein vivorange verification in hadron therapy, through the detection of secondary Prompt Gammas. A major concern with this technique is the poor image quality obtained when the incoming gamma-ray energy is unknown. Compton Cameras with more than two detector planes (multi-layer Compton Cameras) have been proposed as a solution, given that these devices incorporate more signal sequences of interactions to the conventional two interaction events. In particular, three interaction events convey more spectral information as they allow inferring directly the incident gamma-ray energy. A three-layer Compton Telescope based on continuous Lanthanum (III) Bromide crystals coupled to Silicon Photomultipliers is being developed at the IRIS group of IFIC-Valencia. In a previous work we proposed a spectral reconstruction algorithm for two interaction events based on an analytical model for the formation of the signal. To fully exploit the capabilities of our prototype, we present here an extension of the model for three interaction events. Analytical expressions of the sensitivity and the System Matrix are derived and validated against Monte Carlo simulations. Implemented in a List Mode Maximum Likelihood Expectation Maximization algorithm, the proposed model allows us to obtain four-dimensional (energy and position) images by using exclusively three interaction events. We are able to recover the correct spectrum and spatial distribution of gamma-ray sources when ideal data are employed. However, the uncertainties associated to experimental measurements result in a degradation when real data from complex structures are employed. Incorrect estimation of the incident gamma-ray interaction positions, and missing deposited energy associated with escaping secondaries, have been identified as the causes of such degradation by means of a detailed Monte Carlo study. As expected, our current experimental resolution and efficiency to three interaction events prevents us from correctly recovering complex structures of radioactive sources. However, given the better spectral information conveyed by three interaction events, we expect an improvement of the image quality of conventional Compton imaging when including such events. In this regard, future development includes the incorporation of the model assessed in this work to the two interaction events model in order to allow using simultaneously two and three interaction events in the image reconstruction. |
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Address |
[Roser, J.; Munoz, E.; Barrientos, L.; Barrio, J.; Bernabeu, J.; Borja-Lloret, M.; Etxebeste, A.; Llosa, G.; Ros, A.; Viegas, R.; Oliver, J. F.] Inst Fis Corpuscular IFIC CSIC UVEG, Valencia, Spain, Email: Jorge.Roser@ific.uv.es |
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Iop Publishing Ltd |
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English |
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0031-9155 |
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WOS:000552701600001 |
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no |
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yes |
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no |
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IFIC @ pastor @ |
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4481 |
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