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Author Cottin, G.; Helo, J.C.; Hirsch, M.; Titov, A.; Wang, Z.S.
Title Heavy neutral leptons in effective field theory and the high-luminosity LHC Type Journal Article
Year 2021 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 09 Issue 9 Pages 039 - 34pp
Keywords Beyond Standard Model; Effective Field Theories; Neutrino Physics
Abstract (up) Heavy neutral leptons (HNLs) with masses around the electroweak scale are expected to be rather long-lived particles, as a result of the observed smallness of the active neutrino masses. In this work, we study long-lived HNLs in NRSMEFT, a Standard Model (SM) extension with singlet fermions to which we add non-renormalizable operators up to dimension-6. Operators which contain two HNLs can lead to a sizable enhancement of the production cross sections, compared to the minimal case where HNLs are produced only via their mixing with the SM neutrinos. We calculate the expected sensitivities for the ATLAS detector and the future far-detector experiments: AL3X, ANUBIS, CODEX-b, FASER, MATHUSLA, and MoEDAL-MAPP in this setup. The sensitive ranges of the HNL mass and of the active-heavy mixing angle are much larger than those in the minimal case. We study both, Dirac and Majorana, HNLs and discuss how the two cases actually differ phenomenologically, for HNL masses above roughly 100 GeV.
Address [Cottin, Giovanna] Univ Adolfo Ibanez, Fac Artes Liberales, Dept Ciencias, Diagonal Las Torres 2640, Santiago, Chile, Email: giovanna.cottin@uai.cl;
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:000694840800001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4970
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Author Alcaide, J.; Banerjee, S.; Chala, M.; Titov, A.
Title Probes of the Standard Model effective field theory extended with a right-handed neutrino Type Journal Article
Year 2019 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 08 Issue 8 Pages 031 - 18pp
Keywords Beyond Standard Model; Effective Field Theories; Neutrino Physics
Abstract (up) If neutrinos are Dirac particles and, as suggested by the so far null LHC results, any new physics lies at energies well above the electroweak scale, the Standard Model effective field theory has to be extended with operators involving the right-handed neutrinos. In this paper, we study this effective field theory and set constraints on the different dimension-six interactions. To that aim, we use LHC searches for associated production of light (and tau) leptons with missing energy, monojet searches, as well as pion and tau decays. Our bounds are generally above the TeV for order one couplings. One particular exception is given by operators involving top quarks. These provide new signals in top decays not yet studied at colliders. Thus, we also design an LHC analysis to explore these signatures in the tt production. Our results are also valid if the right-handed neutrinos are Majorana and long-lived.
Address [Alcaide, Julien] Univ Valencia, Dept Fis Teor, Dr Moliner 50, E-46100 Burjassot, Spain, Email: julien.alcaide@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:000482463900008 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4120
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Author Chala, M.; Krause, C.; Nardini, G.
Title Signals of the electroweak phase transition at colliders and gravitational wave observatories Type Journal Article
Year 2018 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 07 Issue 7 Pages 062 - 29pp
Keywords Beyond Standard Model; Higgs Physics
Abstract (up) If the electroweak phase transition (EWPT) is of strongly first order due to higher dimensional operators, the scale of new physics generating them is at the TeV scale or below. In this case the effective-field theory (EFT) neglecting operators of dimension higher than six may overlook terms that are relevant for the EWPT analysis. In this article we study the EWPT in the EFT to dimension eight. We estimate the reach of the future gravitational wave observatory LISA for probing the region in which the EWPT is strongly first order and compare it with the capabilities of the Higgs measurements via double-Higgs production at current and future colliders. We also match different UV models to the previously mentioned dimension-eight EFT and demonstrate that, from the top-down point of view, the double-Higgs production is not the best signal to explore these scenarios.
Address [Chala, Mikael] Univ Durham, Phys Dept, Inst Particle Phys Phenomenol, South Rd, Durham DH1 3LE, England, Email: mikael.chala@durham.ac.uk;
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:000438141500014 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3655
Permanent link to this record
 

 
Author Reig, M.
Title The stochastic axiverse Type Journal Article
Year 2021 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 09 Issue 9 Pages 207 - 40pp
Keywords Cosmology of Theories beyond the SM; Beyond Standard Model; Compactification and String Models
Abstract (up) In addition to spectacular signatures such as black hole superradiance and the rotation of CMB polarization, the plenitude of axions appearing in the string axiverse may have potentially dangerous implications. An example is the cosmological overproduction of relic axions and moduli by the misalignment mechanism, more pronounced in regions where the signals mentioned above may be observable, that is for large axion decay constant. In this work, we study the minimal requirements to soften this problem and show that the fundamental requirement is a long period of low-scale inflation. However, in this case, if the inflationary Hubble scale is lower than around O(100) eV, no relic DM axion is produced in the early Universe. Cosmological production of some axions may be activated, via the misalignment mechanism, if their potential minimum changes between inflation and today. As a particular example, we study in detail how the maximal-misalignment mechanism dilutes the effect of dangerous axions and allows the production of axion DM in a controlled way. In this case, the potential of the axion that realises the mechanism shifts by a factor increment theta = pi between the inflationary epoch and today, and the axion starts to oscillate from the top of its potential. We also show that axions with masses m(a) similar to O(1 – 100) H-0 realising the maximal-misalignment mechanism generically behave as dark energy with a decay constant that can take values well below the Planck scale, avoiding problems associated to super-Planckian scales. Finally, we briefly study the basic phenomenological implications of the mechanism and comment on the compatibility of this type of maximally-misaligned quintessence with the swampland criteria.
Address [Reig, Mario] Univ Valencia, CSIC, Inst Fis Corpuscular, C Catedratico Jose Beltran 2, E-46980 Paterna, Valencia, Spain, Email: mario.reig@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:000702371800004 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 4977
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Author Hooper, D.; Leane, R.K.; Tsai, Y.D.; Wegsman, S.; Witte, S.J.
Title A systematic study of hidden sector dark matter: application to the gamma-ray and antiproton excesses Type Journal Article
Year 2020 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 07 Issue 7 Pages 163 - 38pp
Keywords Beyond Standard Model; Cosmology of Theories beyond the SM
Abstract (up) In hidden sector models, dark matter does not directly couple to the particle content of the Standard Model, strongly suppressing rates at direct detection experiments, while still allowing for large signals from annihilation. In this paper, we conduct an extensive study of hidden sector dark matter, covering a wide range of dark matter spins, mediator spins, interaction diagrams, and annihilation final states, in each case determining whether the annihilations are s-wave (thus enabling efficient annihilation in the universe today). We then go on to consider a variety of portal interactions that allow the hidden sector annihilation products to decay into the Standard Model. We broadly classify constraints from relic density requirements and dwarf spheroidal galaxy observations. In the scenario that the hidden sector was in equilibrium with the Standard Model in the early universe, we place a lower bound on the portal coupling, as well as on the dark matter's elastic scattering cross section with nuclei. We apply our hidden sector results to the observed Galactic Center gamma-ray excess and the cosmic-ray antiproton excess. We find that both of these excesses can be simultaneously explained by a variety of hidden sector models, without any tension with constraints from observations of dwarf spheroidal galaxies.
Address [Hooper, Dan; Tsai, Yu-Dai] Fermilab Natl Accelerator Lab, Fermilab, Batavia, IL 60510 USA, Email: dhooper@fnal.gov;
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:000555828300002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4491
Permanent link to this record