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Author (up) Aarrestad, T. et al; Mamuzic, J.; Ruiz de Austri, R. url  doi
openurl 
  Title Benchmark data and model independent event classification for the large hadron collider Type Journal Article
  Year 2022 Publication Scipost Physics Abbreviated Journal SciPost Phys.  
  Volume 12 Issue 1 Pages 043 - 57pp  
  Keywords  
  Abstract We describe the outcome of a data challenge conducted as part of the Dark Machines (https://www.darkmachines.org) initiative and the Les Houches 2019 workshop on Physics at TeV colliders. The challenged aims to detect signals of new physics at the Large Hadron Collider (LHC) using unsupervised machine learning algorithms. First, we propose how an anomaly score could be implemented to define model-independent signal regions in LHC searches. We define and describe a large benchmark dataset, consisting of > 1 billion simulated LHC events corresponding to 10 fb(-1) of proton-proton collisions at a center-of-mass energy of 13 TeV. We then review a wide range of anomaly detection and density estimation algorithms, developed in the context of the data challenge, and we measure their performance in a set of realistic analysis environments. We draw a number of useful conclusions that will aid the development of unsupervised new physics searches during the third run of the LHC, and provide our benchmark dataset for future studies at https://www.phenoMLdata.org. Code to reproduce the analysis is provided at https://github.com/bostdiek/DarkMachines-UnsupervisedChallenge.  
  Address [Aarrestad, Thea; Heinrich, Lukas A.; Jawahar, Pratik; Pierini, Maurizio; Touranakou, Mary; Wozniak, Kinga A.] European Org Nucl Res CERN, CH-1211 Geneva 23, Switzerland  
  Corporate Author Thesis  
  Publisher Scipost Foundation Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2542-4653 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000807448000038 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5256  
Permanent link to this record
 

 
Author (up) Abada, A.; De Romeri, V.; Lucente, M.; Teixeira, A.M.; Toma, T. url  doi
openurl 
  Title Effective Majorana mass matrix from tau and pseudoscalar meson lepton number violating decays Type Journal Article
  Year 2018 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 02 Issue 2 Pages 169 - 57pp  
  Keywords Beyond Standard Model; Neutrino Physics  
  Abstract An observation of any lepton number violating process will undoubtedly point towards the existence of new physics and indirectly to the clear Majorana nature of the exchanged fermion. In this work, we explore the potential of a minimal extension of the Standard Model via heavy sterile fermions with masses in the [0.1-10] GeV range concerning an extensive array of “neutrinoless” meson and tau decay processes. We assume that the Majorana neutrinos are produced on-shell, and focus on three-body decays. We conduct an update on the bounds on the active-sterile mixing elements, vertical bar U-l alpha 4,U-l beta 4 vertical bar, taking into account the most recent experimental bounds (and constraints) and new theoretical inputs, as well as the effects of a finite detector, imposing that the heavy neutrino decay within the detector. This allows to establish up-to-date comprehensive constraints on the sterile fermion parameter space. Our results suggest that the branching fractions of several decays are close to current sensitivities (likely within reach of future facilities), some being already in conflict with current data (as is the case of K-broken vertical bar -> l(alpha)(broken vertical bar)+l(beta)(+)pi(-), and tau(-)->mu(broken vertical bar)pi(-)pi(-)). We use these processes to extract constraints on all entries of an enlarged definition of a 3 x 3 “effective” Majorana neutrino mass matrix m(v)(alpha beta).  
  Address [Abada, Asmaa] Univ Paris Saclay, Univ Paris Sud, CNRS, Lab Phys Theor, 15 Rue Georges Clemenceau, F-91405 Orsay, France, Email: abada@th.u-psud.fr;  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1029-8479 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000426478100001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3511  
Permanent link to this record
 

 
Author (up) Abada, A.; Escribano, P.; Marcano, X.; Piazza, G. url  doi
openurl 
  Title Collider searches for heavy neutral leptons: beyond simplified scenarios Type Journal Article
  Year 2022 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C  
  Volume 82 Issue 11 Pages 1030 - 17pp  
  Keywords  
  Abstract With very few exceptions, the large amount of available experimental bounds on heavy neutral leptons – HNL – have been derived relying on the assumption of the existence of a single (usually Majorana) sterile fermion state that mixes with only one lepton flavour. However, most of the extensions of the Standard Model involving sterile fermions predict the existence of several HNLs, with complex mixing patterns to all flavours. Consequently, most of the experimental bounds for HNLs need to be recast before being applied to a generic scenario. In this work, we focus on LHC searches of heavy neutral leptons and discuss how to reinterpret the available bounds when it comes to consider mixings to all active flavours, not only in the case with a single HNL, but also in the case when more heavy neutral leptons are involved. In the latter case, we also consider the possibility of interference effects and show how the bounds on the parameter space should be recast.  
  Address [Abada, Asmaa; Piazza, Gioacchino] Lab Phys Infinis Irene Joliot Curie 2, Pole Theorie, UMR 9012, CNRS,IN2P3, 15 Rue Georges Clemenceau, F-91400 Orsay, France, Email: asmaa.abada@ijclab.in2p3.fr;  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1434-6044 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000884904400006 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5418  
Permanent link to this record
 

 
Author (up) Abbar, S.; Capozzi, F. url  doi
openurl 
  Title Suppression of fast neutrino flavor conversions occurring at large distances in core-collapse supernovae Type Journal Article
  Year 2022 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 03 Issue 3 Pages 051 - 13pp  
  Keywords supernova neutrinos; core-collapse supernovae; neutrino astronomy; supernovas  
  Abstract Neutrinos propagating in dense neutrino media such as core-collapse supernovae and neutron star merger remnants can experience the so-called fast flavor conversions on scales much shorter than those expected in vacuum. A very generic class of fast flavor instabilities is the ones which are produced by the backward scattering of neutrinos off the nuclei at relatively large distances from the supernova core. In this study we demonstrate that despite their ubiquity, such fast instabilities are unlikely to cause significant flavor conversions if the population of neutrinos in the backward direction is not large enough. Indeed, the scattering-induced instabilities can mostly impact the neutrinos traveling in the backward direction, which represent only a small fraction of neutrinos at large radii. We show that this can be explained by the shape of the unstable flavor eigenstates, which can be extremely peaked at the backward angles.  
  Address [Abbar, Sajad] Max Planck Inst Phys & Astrophys, Werner Heisenberg Inst, Fohringer Ring 6, D-80805 Munich, Germany, Email: abbar@mpp.mpg.de;  
  Corporate Author Thesis  
  Publisher IOP Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000776551600002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5186  
Permanent link to this record
 

 
Author (up) Abdalla, E. et al; Mena, O. url  doi
openurl 
  Title Cosmology intertwined: A review of the particle physics, astrophysics, and cosmology associated with the cosmological tensions and anomalies Type Journal Article
  Year 2022 Publication Journal of High Energy Astrophysics Abbreviated Journal J. High Energy Astrophys.  
  Volume 34 Issue Pages 49-211  
  Keywords  
  Abstract The standard Lambda Cold Dark Matter (Lambda CDM) cosmological model provides a good description of a wide range of astrophysical and cosmological data. However, there are a few big open questions that make the standard model look like an approximation to a more realistic scenario yet to be found. In this paper, we list a few important goals that need to be addressed in the next decade, taking into account the current discordances between the different cosmological probes, such as the disagreement in the value of the Hubble constant H-0, the sigma(8)-S-8 tension, and other less statistically significant anomalies. While these discordances can still be in part the result of systematic errors, their persistence after several years of accurate analysis strongly hints at cracks in the standard cosmological scenario and the necessity for new physics or generalisations beyond the standard model. In this paper, we focus on the 5.0 sigma tension between the Planck CMB estimate of the Hubble constant H-0 and the SH0ES collaboration measurements. After showing the H-0 evaluations made from different teams using different methods and geometric calibrations, we list a few interesting new physics models that could alleviate this tension and discuss how the next decade's experiments will be crucial. Moreover, we focus on the tension of the Planck CMB data with weak lensing measurements and redshift surveys, about the value of the matter energy density Omega(m), and the amplitude or rate of the growth of structure (sigma(8), f sigma(8)). We list a few interesting models proposed for alleviating this tension, and we discuss the importance of trying to fit a full array of data with a single model and not just one parameter at a time. Additionally, we present a wide range of other less discussed anomalies at a statistical significance level lower than the H-0-S-8 tensions which may also constitute hints towards new physics, and we discuss possible generic theoretical approaches that can collectively explain the non-standard nature of these signals. Finally, we give an overview of upgraded experiments and next-generation space missions and facilities on Earth that will be of crucial importance to address all these open questions.  
  Address [Abdalla, Elcio] Univ Sao Paulo, Inst Fis, CP 66318, BR-0531597 Sao Paulo, Brazil, Email: e.divalentino@sheffield.ac.uk  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2214-4048 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000807122400002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5465  
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