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Author Beltran Jimenez, J.; Delhom, A.; Olmo, G.J.; Orazi, E.
Title Born-Infeld gravity: Constraints from light-by-light scattering and an effective field theory perspective Type Journal Article
Year 2021 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 820 Issue Pages 136479 - 6pp
Keywords
Abstract By using a novel technique that establishes a correspondence between general relativity and metric-affine theories based on the Ricci tensor, we are able to set stringent constraints on the free parameter of Born-Infeld gravity from the ones recently obtained for Born-Infeld electrodynamics by using light-by light scattering data from ATLAS. We also discuss how these gravity theories plus matter fit within an effective field theory framework.
Address (up) [Beltran Jimenez, Jose] Univ Salamanca, Dept Fis Fundamental, E-37008 Salamanca, Spain, Email: jose.beltran@usal.es;
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 0370-2693 ISBN Medium
Area Expedition Conference
Notes WOS:000701707400005 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4978
Permanent link to this record
 
 
Author Beltran Jimenez, J.; Delhom, A.
Title Instabilities in metric-affine theories of gravity with higher order curvature terms Type Journal Article
Year 2020 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C
Volume 80 Issue 6 Pages 585 - 27pp
Keywords
Abstract We discuss the presence of ghostly instabilities for metric-affine theories constructed with higher order curvature terms. We mainly focus on theories containing only the Ricci tensor and show the crucial role played by the projective symmetry. The pathological modes arise from the absence of a pure kinetic term for the projective mode and the non-minimal coupling of a 2-form field contained in the connection, and which can be related to the antisymmetric part of the metric in non-symmetric gravity theories. The couplings to matter are considered at length and cannot be used to render the theories stable. We discuss different procedures to avoid the ghosts by adding additional constraints. We finally argue how these pathologies are expected to be present in general metric-affine theories unless much care is taken in their construction.
Address (up) [Beltran Jimenez, Jose] Univ Salamanca, Dept Fis Fundamental, Salamanca 37008, Spain, Email: jose.beltran@usal.es;
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:000546247100009 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 4457
Permanent link to this record
 
 
Author Beltran, R.; Cottin, G.; Helo, J.C.; Hirsch, M.; Titov, A.; Wang, Z.S.
Title Long-lived heavy neutral leptons from mesons in effective field theory Type Journal Article
Year 2023 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 01 Issue 1 Pages 015 - 38pp
Keywords New Light Particles; SMEFT; Sterile or Heavy Neutrinos
Abstract In the framework of the low-energy effective field theory of the Standard Model extended with heavy neutral leptons (HNLs), we calculate the production rates of HNLs from meson decays triggered by dimension-six operators. We consider both lepton number-conserving and lepton-number-violating four-fermion operators involving either a pair of HNLs or a single HNL. Assuming that HNLs are long-lived, we perform simulations and investigate the reach of the proposed far detectors at the high-luminosity LHC to (i) active-heavy neutrino mixing and (ii) the Wilson coefficients associated with the effective operators, for HNL masses below the mass of the B-meson. We further convert the latter to the associated new-physics scales. Our results show that scales in excess of hundreds of TeV and the active-heavy mixing squared as small as 10(-15 )can be probed by these experiments.
Address (up) [Beltran, Rebeca; Hirsch, Martin] Univ Valencia, AHEP Grp, Inst Fis Corpuscular, CSIC, Apartado 22085, E-46071 Valencia, Spain, Email: rebeca.beltran@ific.uv.es;
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:000909520000005 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5455
Permanent link to this record
 
 
Author Beltran, R.; Cottin, G.; Helo, J.C.; Hirsch, M.; Titov, A.; Wang, Z.S.
Title Long-lived heavy neutral leptons at the LHC: four-fermion single-N-R operators Type Journal Article
Year 2022 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 01 Issue 1 Pages 044 - 18pp
Keywords Beyond Standard Model; Effective Field Theories; Neutrino Physics
Abstract Interest in searches for heavy neutral leptons (HNLs) at the LHC has increased considerably in the past few years. In the minimal scenario, HNLs are produced and decay via their mixing with active neutrinos in the Standard Model (SM) spectrum. However, many SM extensions with HNLs have been discussed in the literature, which sometimes change expectations for LHC sensitivities drastically. In the N-R SMEFT, one extends the SM effective field theory with operators including SM singlet fermions, which allows to study HNL phenomenology in a “model independent” way. In this paper, we study the sensitivity of ATLAS to HNLs in the N-R SMEFT for four-fermion operators with a single HNL. These operators might dominate both production and decay of HNLs, and we find that new physics scales in excess of 20 TeV could be probed at the high-luminosity LHC.
Address (up) [Beltran, Rebeca; Hirsch, Martin] Univ Valencia, AHEP Grp, Inst Fis Corpuscular, CSIC, Apartado 22085, E-46071 Valencia, Spain, Email: rebeca.beltran@ifis.uv.es;
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:000742012500001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5079
Permanent link to this record
 
 
Author Beltran, R.; Günther, J.; Hirsch, M.; Titov, A.; Wang, Z.S.
Title Heavy neutral leptons from kaons in effective field theory Type Journal Article
Year 2024 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 109 Issue 11 Pages 115014 - 19pp
Keywords
Abstract In the framework of the low -energy effective theory containing, in addition to the Standard -Model fields, heavy neutral leptons (HNLs), we compute the decay rates of neutral and charged kaons into HNLs. We consider both lepton -number -conserving and lepton -number -violating four-fermion operators, taking into account also the contribution of active -heavy neutrino mixing. Assuming that the produced HNLs are longlived, we perform simulations and calculate the sensitivities of future long -lived -particle (LLP) detectors at the high -luminosity LHC as well as the near detector of the Deep Underground Neutrino Experiment (DUNE -ND) to the considered scenario. When applicable, we also recast the existing bounds on the minimal mixing case obtained by NA62, T2K, and PS191. Our findings show that, while the future LHC LLP detectors can probe currently allowed parameter space only in certain benchmark scenarios, DUNE -ND should be sensitive to parameter space beyond the current bounds in almost all the benchmark scenarios, and, for some of the effective operators considered, it can even probe new -physics scales in excess of 3000 TeV.
Address (up) [Beltran, Rebeca; Hirsch, Martin] Univ Valencia, CSIC, AHEP Grp, Inst Fis Corpuscular, Apartado 22085, E-46071 Valencia, Spain, Email: rebeca.beltran@ific.uv.es;
Corporate Author Thesis
Publisher 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 2470-0010 ISBN Medium
Area Expedition Conference
Notes WOS:001250419300003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 6165
Permanent link to this record
 
 
Author Beltran, R.; Cottin, G.; Hirsch, M.; Titov, A.; Wang, Z.S.
Title Reinterpretation of searches for long-lived particles from meson decays Type Journal Article
Year 2023 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 05 Issue 5 Pages 031 - 31pp
Keywords New Light Particles; Axions and ALPs; Sterile or Heavy Neutrinos; SMEFT
Abstract Many models beyond the Standard Model predict light and feebly interacting particles that are often long-lived. These long-lived particles (LLPs) in many cases can be produced from meson decays. In this work, we propose a simple and quick reinterpretation method for models predicting LLPs produced from meson decays. With the method, we are not required to run Monte-Carlo simulation, implement detector geometries and efficiencies, or apply experimental cuts in an event analysis, as typically done in recasting and reinterpretation works. The main ingredients our method requires are only the theoretical input, allowing for computation of the production and decay rates of the LLPs. There are two conditions for the method to work: firstly, the LLPs in the models considered should be produced from a set of mesons with similar mass and lifetime (or the same meson) and second, the LLPs should, in general, have a lab-frame decay length much larger than the distance between the interaction point and the detector. As an example, we use this method to reinterpret exclusion bounds on heavy neutral leptons (HNLs) in the minimal “3+1” scenario, into those for HNLs in the general effective-field-theory framework as well as for axion-like particles. We are able to reproduce existing results, and obtain new bounds via reinterpretation of past experimental results, in particular, from CHARM and Belle.
Address (up) [Beltran, Rebeca; Hirsch, Martin] Univ Valencia, Inst Fis Corpuscular, AHEP Grp, CSIC, 22085, E-46071 Valencia, Spain, Email: wzs@mx.nthu.edu.tw
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:000983316500002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5528
Permanent link to this record
 
 
Author Beltran, R.; Cepedello, R.; Hirsch, M.
Title Tree-level UV completions for NRSMEFT d=6 and d=7 operators Type Journal Article
Year 2023 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 08 Issue 8 Pages 31pp
Keywords Baryon/Lepton Number Violation; SMEFT; Sterile or Heavy Neutrinos
Abstract We study ultra-violet completions for operators in standard model effective field theory extended with right-handed neutrinos (NRSMEFT). Using a diagrammatic method, we generate systematically lists of possible tree-level completions involving scalars, fermions or vectors for all operators at d = 6 and d = 7, which contain at least one right-handed neutrino. We compare our lists of possible UV models to the ones found for pure SMEFT. We also discuss how the observation of LNV processes via NRSMEFT operators at the LHC can be related to Majorana neutrino masses of the standard model neutrinos.
Address (up) [Beltran, Rebeca; Hirsch, Martin] Univ Valencia, Inst Fis Corpuscular, CSIC, C Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: rebeca.beltran@ific.uv.es;
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:001054461600003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5625
Permanent link to this record
 
 
Author Beltran-Palau, P.; Ferreiro, A.; Navarro-Salas, J.; Pla, S.
Title Breaking of adiabatic invariance in the creation of particles by electromagnetic backgrounds Type Journal Article
Year 2019 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 100 Issue 8 Pages 085014 - 12pp
Keywords
Abstract Particles are spontaneously created from the vacuum by time-varying gravitational or electromagnetic backgrounds. It has been proven that the particle number operator in an expanding universe is an adiabatic invariant. In this paper we show that, in some special cases, the expected adiabatic invariance of the particle number fails in presence of electromagnetic backgrounds. In order to do this, we consider as a prototype a Sauter-type electric pulse. Furthermore, we also show a close relation between the breaking of the adiabatic invariance and the emergence of the axial anomaly.
Address (up) [Beltran-Palau, Pau; Ferreiro, Antonio; Navarro-Salas, Jose; Pla, Silvia] Univ Valencia, CSIC, Ctr Mixto, Fac Fis,Dept Fis Teor, E-46100 Valencia, Spain, Email: pau.beltran@uv.es;
Corporate Author Thesis
Publisher 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 2470-0010 ISBN Medium
Area Expedition Conference
Notes WOS:000491467800009 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 4184
Permanent link to this record
 
 
Author Beltran-Palau, P.; del Rio, A.; Nadal-Gisbert, S.; Navarro-Salas, J.
Title Note on the pragmatic mode-sum regularization method: Translational-splitting in a cosmological background Type Journal Article
Year 2021 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 103 Issue 10 Pages 105002 - 9pp
Keywords
Abstract The point-splitting renormalization method offers a prescription to calculate finite expectation values of quadratic operators constructed from quantum fields in a general curved spacetime. It has been recently shown by Levi and Ori that when the background metric possesses an isometry, like stationary or spherically symmetric black holes, the method can be upgraded into a pragmatic procedure of renormalization that produces efficient numerical calculations. In this paper we show that when the background enjoys three-dimensional spatial symmetries, like homogeneous expanding universes, the above pragmatic regularization technique reduces to the well-established adiabatic regularization method.
Address (up) [Beltran-Palau, Pau; Nadal-Gisbert, Sergi; Navarro-Salas, Jose] Univ Valencia, Dept Fis Teor, Ctr Mixto, CSIC,Fac Fis, Valencia 46100, Spain, Email: pau.beltran@uv.es;
Corporate Author Thesis
Publisher 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 2470-0010 ISBN Medium
Area Expedition Conference
Notes WOS:000655874400009 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4845
Permanent link to this record
 
 
Author Beltran-Palau, P.; Navarro-Salas, J.; Pla, S.
Title Translational anomaly of chiral fermions in two dimensions Type Journal Article
Year 2019 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 99 Issue 10 Pages 105008 - 5pp
Keywords
Abstract It is well known that a quantized two-dimensional Weyl fermion coupled to gravity spoils general covariance and breaks the covariant conservation of the energy-momentum tensor. In this brief article, we point out that the quantum conservation of the momentum can also fail in flat spacetime, provided the Weyl fermion is coupled to a time-varying homogeneous electric field. This signals a quantum anomaly of the space-translation symmetry, which has not been highlighted in the literature so far.
Address (up) [Beltran-Palau, Pau; Navarro-Salas, Jose; Pla, Silvia] Univ Valencia, Dept Fis Teor, Ctr Mixto, CSIC,Fac Fis, E-46100 Valencia, Spain, Email: pau.beltran@uv.es;
Corporate Author Thesis
Publisher 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 2470-0010 ISBN Medium
Area Expedition Conference
Notes WOS:000468223500013 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 4011
Permanent link to this record