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Author Albandea, D.; Del Debbio, L.; Hernandez, P.; Kenway, R.; Marsh Rossney, J.; Ramos, A.
Title Learning trivializing flows Type Journal Article
Year 2023 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C
Volume 83 Issue 7 Pages 676 - 14pp
Keywords
Abstract The recent introduction of machine learning techniques, especially normalizing flows, for the sampling of lattice gauge theories has shed some hope on improving the sampling efficiency of the traditional hybrid Monte Carlo (HMC) algorithm. In this work we study a modified HMC algorithm that draws on the seminal work on trivializing flows by L & uuml;scher. Autocorrelations are reduced by sampling from a simpler action that is related to the original action by an invertible mapping realised through Normalizing Flows models with a minimal set of training parameters. We test the algorithm in a f(4) theory in 2D where we observe reduced autocorrelation times compared with HMC, and demonstrate that the training can be done at small unphysical volumes and used in physical conditions. We also study the scaling of the algorithm towards the continuum limit under various assumptions on the network architecture.
Address [Albandea, D.; Hernandez, P.; Ramos, A.] Edificio Inst Invest, IFIC CSIC UVEG, Apt 22085, Valencia 46071, Spain, Email: david.albandea@uv.es
Corporate Author Thesis
Publisher (down) 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:001066712500003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5698
Permanent link to this record
 
 
Author Sandner, S.; Hernandez, P.; Lopez-Pavon, J.; Rius, N.
Title Predicting the baryon asymmetry with degenerate right-handed neutrinos Type Journal Article
Year 2023 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 11 Issue 11 Pages 153 - 37pp
Keywords Baryo-and Leptogenesis; Sterile or Heavy Neutrinos; Early Universe Particle Physics
Abstract We consider the generation of a baryon asymmetry in an extension of the Standard Model with two singlet Majorana fermions that are degenerate above the electroweak phase transition. The model can explain neutrino masses as well as the observed matter-antimatter asymmetry, for masses of the heavy singlets below the electroweak scale. The only physical CP violating phases in the model are those in the PMNS mixing matrix, i.e. the Dirac phase and a Majorana phase that enter light neutrino observables. We present an accurate analytic approximation for the baryon asymmetry in terms of CP flavour invariants, and derive the correlations with neutrino observables. We demonstrate that the measurement of CP violation in neutrino oscillations as well as the mixings of the heavy neutral leptons with the electron, muon and tau flavours suffice to pin down the matter-antimatter asymmetry from laboratory measurements.
Address [Sandner, S.] Univ Valencia, Inst Fis Corpuscular, Edificio Inst Invest,Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: stefan.sandner@ific.uv.es;
Corporate Author Thesis
Publisher (down) 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:001111979900002 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 5869
Permanent link to this record
 
 
Author Hernandez, P.; Pena, C.; Ramos, A.; Gomez-Cadenas, J.J.
Title A new formulation of compartmental epidemic modelling for arbitrary distributions of incubation and removal times Type Journal Article
Year 2021 Publication Plos One Abbreviated Journal PLoS One
Volume 16 Issue 2 Pages e0244107 - 22pp
Keywords
Abstract The paradigm for compartment models in epidemiology assumes exponentially distributed incubation and removal times, which is not realistic in actual populations. Commonly used variations with multiple exponentially distributed variables are more flexible, yet do not allow for arbitrary distributions. We present a new formulation, focussing on the SEIR concept that allows to include general distributions of incubation and removal times. We compare the solution to two types of agent-based model simulations, a spatially homogeneous one where infection occurs by proximity, and a model on a scale-free network with varying clustering properties, where the infection between any two agents occurs via their link if it exists. We find good agreement in both cases. Furthermore a family of asymptotic solutions of the equations is found in terms of a logistic curve, which after a non-universal time shift, fits extremely well all the microdynamical simulations. The formulation allows for a simple numerical approach; software in Julia and Python is provided.
Address [Hernandez, Pilar] Univ Valencia, Dept Fis Teor, Valencia, Spain, Email: m.pilar.hernandez@uv.es
Corporate Author Thesis
Publisher (down) Public Library Science Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes WOS:000616739700053 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4750
Permanent link to this record
 
 
Author Vincent, A.C.; Fernandez Martinez, E.; Hernandez, P.; Mena, O.; Lattanzi, M.
Title Revisiting cosmological bounds on sterile neutrinos Type Journal Article
Year 2015 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 04 Issue 4 Pages 006 - 23pp
Keywords particle physics – cosmology connection; cosmological neutrinos; cosmology of theories beyond the SM
Abstract We employ state-of-the art cosmological observables including supernova surveys and BAO information to provide constraints on the mass and mixing angle of a non-resonantly produced sterile neutrino species, showing that cosmology can effectively rule out sterile neutrinos which decay between BBN and the present day. The decoupling of an additional heavy neutrino species can modify the time dependence of the Universe's expansion between BBN and recombination and, in extreme cases, lead to an additional matter-dominated period; while this could naively lead to a younger Universe with a larger Hubble parameter, it could later be compensated by the extra radiation expected in the form of neutrinos from sterile decay. However, recombination-era observables including the Cosmic Microwave Background (CMB), the shift parameter R-CMB and the sound horizon r(s) from Baryon Acoustic Oscillations (BAO) severely constrain this scenario. We self-consistently include the full time-evolution of the coupled sterile neutrino and standard model sectors in an MCMC, showing that if decay occurs after BBN, the sterile neutrino is essentially bounded by the constraint sin(2) theta less than or similar to 0.026(m(s)/eV)(-2).
Address [Vincent, Aaron C.] Univ Durham, Dept Phys, IPPP, Durham DH1 3LE, England, Email: aaron.vincent@durham.ac.uk;
Corporate Author Thesis
Publisher (down) 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:000355742500007 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2261
Permanent link to this record
 
 
Author Alekhin, S. et al; Hernandez, P.
Title A facility to search for hidden particles at the CERN SPS: the SHiP physics case Type Journal Article
Year 2016 Publication Reports on Progress in Physics Abbreviated Journal Rep. Prog. Phys.
Volume 79 Issue 12 Pages 124201 - 137pp
Keywords beyond the standard model physics; intensity frontier experiment; hidden sectors; heavy neutral leptons; dark photons
Abstract This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (search for hidden particles) experiment is intended to hunt for new physics in the largely unexplored domain of very weakly interacting particles with masses below the Fermi scale, inaccessible to the LHC experiments, and to study tau neutrino physics. The same proton beam setup can be used later to look for decays of tau-leptons with lepton flavour number non-conservation, tau -> 3 μand to search for weakly-interacting sub-GeV dark matter candidates. We discuss the evidence for physics beyond the standard model and describe interactions between new particles and four different portals-scalars, vectors, fermions or axion-like particles. We discuss motivations for different models, manifesting themselves via these interactions, and how they can be probed with the SHiP experiment and present several case studies. The prospects to search for relatively light SUSY and composite particles at SHiP are also discussed. We demonstrate that the SHiP experiment has a unique potential to discover new physics and can directly probe a number of solutions of beyond the standard model puzzles, such as neutrino masses, baryon asymmetry of the Universe, dark matter, and inflation.
Address [Alekhin, Sergey] DESY, Platanenallee 6, D-15738 Zeuthen, Germany, Email: oleg.ruchayskiy@cern.ch
Corporate Author Thesis
Publisher (down) 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 0034-4885 ISBN Medium
Area Expedition Conference
Notes WOS:000387025400001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2852
Permanent link to this record
 
 
Author Hernandez, P.
Title CP violation in the neutrino sector: The new frontier Type Journal Article
Year 2012 Publication Comptes Rendus Physique Abbreviated Journal C. R. Phys.
Volume 13 Issue 2 Pages 186-192
Keywords Flavour physics; Neutrino physics; Matter-antimatter asymmetry
Abstract The discovery of neutrino masses has revealed a new flavour sector in the Standard Model. Just like the quark flavour sector, it contains a seed of CP violation, resulting in an asymmetric behaviour of matter and antimatter. It is argued that this new source of leptonic CP violation may be discovered in more precise neutrino oscillation experiments involving neutrino beams with energies in the GeV range that will be sent to distances of a few thousand kilometres.
Address [Hernandez, Pilar] Dpto Fis Teor UV, Valencia 46071, Spain, Email: m.pilar.hernandez@uv.es
Corporate Author Thesis
Publisher (down) Elsevier France-Editions Scientifiques Medicales Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1631-0705 ISBN Medium
Area Expedition Conference
Notes WOS:000301037700015 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 934
Permanent link to this record
 
 
Author Bernardoni, F.; Garron, N.; Hernandez, P.; Necco, S.; Pena, C.
Title Probing the chiral regime of N-f=2 QCD with mixed actions Type Journal Article
Year 2011 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 83 Issue 5 Pages 054503 - 17pp
Keywords
Abstract We report on our first experiences with a mixed action setup with overlap valence quarks and nonperturbatively O(a) improved Wilson sea quarks. For the latter we employ CLS N-f = 2 configurations with light sea-quark masses at small lattice spacings. Exact chiral symmetry allows to consider very light valence quarks and explore the matching to (partially-quenched) Chiral Perturbation Theory (ChPT) in a mixed epsilon/p-regime. We compute the topological susceptibility and the low-lying spectrum of the massless Neuberger-Dirac operator for three values of the sea-quark mass, and compare the sea-quark mass dependence to NLO ChPT in the mixed regime. This provides two different determinations of the chiral condensate, as well as information about some NLOlow-energy couplings. Our results allow to test the consistency of the mixed-regime approach to ChPT, as well as of the mixed action framework.
Address [Bernardoni, F.; Hernandez, P.] Univ Valencia, Inst Fis Corpuscular, CSIC, E-46071 Valencia, Spain
Corporate Author Thesis
Publisher (down) Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1550-7998 ISBN Medium
Area Expedition Conference
Notes ISI:000288389300005 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 546
Permanent link to this record
 
 
Author Bayes, R.; Laing, A.; Soler, F.J.P.; Cervera-Villanueva, A.; Gomez-Cadenas, J.J.; Hernandez, P.; Martin-Albo, J.; Burguet-Castell, J.
Title Golden channel at a neutrino factory revisited: Improved sensitivities from a magnetized iron neutrino detector Type Journal Article
Year 2012 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 86 Issue 9 Pages 093015 - 27pp
Keywords
Abstract This paper describes the performance and sensitivity to neutrino mixing parameters of a Magnetised Iron Neutrino Detector at a Neutrino Factory with a neutrino beam created from the decay of 10 GeV muons. Specifically, it is concerned with the ability of such a detector to detect muons of the opposite sign to those stored (wrong-sign muons) while suppressing contamination of the signal from the interactions of other neutrino species in the beam. A new, more realistic simulation and analysis, which improves the efficiency of this detector at low energies, has been developed using the GENIE neutrino event generator and the GEANT4 simulation toolkit. Low-energy neutrino events down to 1 GeV were selected, while reducing backgrounds to the 10(-4) level. Signal efficiency plateaus of similar to 60% for nu(mu) and similar to 70% for (nu) over bar (mu) events were achieved starting at similar to 5 GeV. Contamination from the nu(mu) -> nu(tau) oscillation channel was studied for the first time and was found to be at the level between 1% and 4%. Full response matrices are supplied for all the signal and background channels from 1 GeV to 10 GeV. The sensitivity of an experiment involving a Magnetised Iron Neutrino Detector detector of 100 ktons at 2000 km from the Neutrino Factory is calculated for the case of sin(2)2 theta(13) similar to 10(-1). For this value of theta(13), the accuracy in the measurement of the CP-violating phase is estimated to be Delta delta(CP) similar to 3 degrees-5 degrees, depending on the value of delta(CP), the CP coverage at 5 sigma is 85% and the mass hierarchy would be determined with better than 5 sigma level for all values of delta(CP).
Address [Bayes, R.; Laing, A.; Soler, F. J. P.] Univ Glasgow, Sch Phys & Astron, Glasgow, Lanark, Scotland
Corporate Author Thesis
Publisher (down) Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1550-7998 ISBN Medium
Area Expedition Conference
Notes WOS:000310868700002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1224
Permanent link to this record
 
 
Author Edgecock, T.R. et al; Agarwalla, S.K.; Cervera-Villanueva, A.; Donini, A.; Ghosh, T.; Gomez-Cadenas, J.J.; Hernandez, P.; Martin-Albo, J.; Mena, O.
Title High intensity neutrino oscillation facilities in Europe Type Journal Article
Year 2013 Publication Physical Review Special Topics-Accelerators and Beams Abbreviated Journal Phys. Rev. Spec. Top.-Accel. Beams
Volume 16 Issue 2 Pages 021002 - 18pp
Keywords
Abstract The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Frejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of mu(+) and mu(-) beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular He-6 and Ne-18, also stored in a ring. The far detector is also the MEMPHYS detector in the Frejus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive.
Address [Edgecock, T. R.; Caretta, O.; Davenne, T.; Densam, C.; Fitton, M.; Kelliher, D.; Loveridge, P.; Machida, S.; Prior, C.; Rogers, C.; Rooney, M.; Thomason, J.; Wilcox, D.] STFC Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England
Corporate Author Thesis
Publisher (down) Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-4402 ISBN Medium
Area Expedition Conference
Notes WOS:000315152000001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1333
Permanent link to this record
 
 
Author Bross, A.; Wands, R.; Bayes, R.; Laing, A.; Soler, F.J.P.; Cervera-Villanueva, A.; Ghosh, T.; Gomez-Cadenas, J.J.; Hernandez, P.; Martin-Albo, J.; Burguet-Castell, J.
Title Toroidal magnetized iron neutrino detector for a neutrino factory Type Journal Article
Year 2013 Publication Physical Review Special Topics-Accelerators and Beams Abbreviated Journal Phys. Rev. Spec. Top.-Accel. Beams
Volume 16 Issue 8 Pages 081002 - 16pp
Keywords
Abstract A neutrino factory has unparalleled physics reach for the discovery and measurement of CP violation in the neutrino sector. A far detector for a neutrino factory must have good charge identification with excellent background rejection and a large mass. An elegant solution is to construct a magnetized iron neutrino detector (MIND) along the lines of MINOS, where iron plates provide a toroidal magnetic field and scintillator planes provide 3D space points. In this paper, the current status of a simulation of a toroidal MIND for a neutrino factory is discussed in light of the recent measurements of large theta(13). The response and performance using the 10 GeV neutrino factory configuration are presented. It is shown that this setup has equivalent delta(CP) reach to a MIND with a dipole field and is sensitive to the discovery of CP violation over 85% of the values of delta(CP).
Address [Bross, A.; Wands, R.] Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA, Email: paul.soler@glasgow.ac.uk
Corporate Author Thesis
Publisher (down) Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-4402 ISBN Medium
Area Expedition Conference
Notes WOS:000323389400001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1559
Permanent link to this record