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Author Fonseca, R.M.; Hirsch, M. url  doi
openurl 
  Title Gauge vectors and double beta decay Type Journal Article
  Year 2017 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 95 Issue 3 Pages 035033 - 14pp  
  Keywords  
  Abstract We discuss contributions to neutrinoless double beta (0 nu beta beta) decay involving vector bosons. The starting point is a list of all possible vector representations that may contribute to 0 nu beta beta decay via d = 9 or d = 11 operators at tree level. We then identify gauge groups which contain these vectors in the adjoint representation. Even though the complete list of vector fields that can contribute to 0 nu beta beta up to d = 11 is large (a total of 46 vectors), only a few of them can be gauge bosons of phenomenologically realistic groups. These latter cases are discussed in some more detail, and lower (upper) limits on gauge boson masses (mixing angles) are derived from the absence of 0 nu beta beta decay.  
  Address (up) [Fonseca, Renato M.; Hirsch, Martin] Univ Valencia, CSIC, Inst Fis Corpuscular, AHEP Grp, Parc Cient Paterna,Calle Catedrat Jose Beltran, E-46980 Paterna, Valencia, Spain, Email: renato.fonseca@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:000396024300010 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3012  
Permanent link to this record
 
 
Author Fonseca, R.M.; Hirsch, M. url  doi
openurl 
  Title A flipped 331 model Type Journal Article
  Year 2016 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 08 Issue 8 Pages 003 - 12pp  
  Keywords Beyond Standard Model; Gauge Symmetry; Neutrino Physics  
  Abstract Models based on the extended SU(3)(C) x SU(3)(L) x U(1)(X) (331) gauge group usually follow a common pattern: two families of left-handed quarks are placed in anti triplet representations of the SU(3)(L) group; the remaining quark family, as well as the left-handed leptons, are assigned to triplets (or vice-versa). In this work we present a flipped 331 model where this scheme is reversed: all three quark families are in the same representation and it is the lepton families which are discriminated by the gauge symmetry. We discuss fermion masses and mixing, as well as Z' interactions, in a minimal model implementing this idea.  
  Address (up) [Fonseca, Renato M.; Hirsch, Martin] Univ Valencia, CSIC, Inst Fis Corpuscular, AHEP Grp, Parc Cient Paterna,Calle Jose Beltran, E-46980 Paterna, Valencia, Spain, Email: renato.fonseca@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:000381218300003 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 2782  
Permanent link to this record
 
 
Author Fonseca, R.M.; Hirsch, M. url  doi
openurl 
  Title Delta L >= 4 lepton number violating processes Type Journal Article
  Year 2018 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 98 Issue 1 Pages 015035 - 12pp  
  Keywords  
  Abstract We discuss the experimental prospects for observing processes which violate lepton number (Delta L) in four units ( or more). First, we reconsider neutrinoless quadruple beta decay, deriving a model independent and very conservative lower limit on its half- life of the order of 10(41) ys for Nd-150. This renders quadruple beta decay unobservable for any feasible experiment. We then turn to a more general discussion of different possible low-energy processes with values Delta L >= 4. A simple operator analysis leads to rather pessimistic conclusions about the observability at low-energy experiments in all cases we study. However, the situation looks much brighter for accelerator experiments. For two example models with Delta L = 4 and another one with Delta L = 5, we show how the LHC or a hypothetical future pp collider, such as the FCC, could probe multilepton number violating operators at the TeV scale.  
  Address (up) [Fonseca, Renato M.; Hirsch, Martin] Univ Valencia, CSIC, Inst Fis Corpuscular, AHEP Grp, Spain Edificio Inst Paterna,Apartado 22085, E-46071 Valencia, Spain, Email: renato.fonseca@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:000439791500005 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3675  
Permanent link to this record
 
 
Author Gonzalez, L.; Helo, J.C.; Hirsch, M.; Kovalenko, S.G. url  doi
openurl 
  Title Scalar-mediated double beta decay and LHC Type Journal Article
  Year 2016 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 12 Issue 12 Pages 130 - 15pp  
  Keywords Beyond Standard Model; Neutrino Physics  
  Abstract The decay rate of neutrinoless double beta (0 nu beta beta) decay could be dominated by Lepton Number Violating (LNV) short-range diagrams involving only heavy scalar intermediate particles, known as “topology-II” diagrams. Examples are diagrams with diquarks, leptoquarks or charged scalars. Here, we compare the LNV discovery potentials of the LHC and 0 nu beta beta-decay experiments, resorting to three example models, which cover the range of the optimistic-pessimistic cases for 0 nu beta beta decay. We use the LHC constraints from dijet as well as leptoquark searches and find that already with 20/fb the LHC will test interesting parts of the parameter space of these models, not excluded by the current limits on 0 nu beta beta-decay.  
  Address (up) [Gonzalez, L.; Helo, J. C.; Kovalenko, S. G.] Univ Tecn Federico Santa Maria, Ctr Cient Tecnol Valparaiso, Casilla 110-5, Valparaiso, Chile, Email: lorena.gonzalez@alumnos.usm.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:000399774600001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3060  
Permanent link to this record
 
 
Author Gonzalez, M.; Kovalenko, S.G.; Hirsch, M. url  doi
openurl 
  Title QCD running in neutrinoless double beta decay: Short-range mechanisms Type Journal Article
  Year 2016 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 93 Issue 1 Pages 013017 - 11pp  
  Keywords  
  Abstract The decay rate of neutrinoless double beta (0 nu beta beta) decay contains terms from heavy particle exchange, which lead to dimension-9 (d = 9) six fermion operators at low energies. Limits on the coefficients of these operators have been derived previously neglecting the running of the operators between the high scale, where they are generated, and the energy scale of 0 nu beta beta decay, where they are measured. Here we calculate the leading-order QCD corrections to all possible d = 9 operators contributing to the 0 nu beta beta amplitude and use renormalization group running to calculate 1-loop improved limits. Numerically, QCD running dramatically changes some limits by factors of the order of or larger than typical uncertainties in nuclear matrix element calculations. For some specific cases, operator mixing in the running changes limits even by up to 3 orders of magnitude. Our results can be straightforwardly combined with new experimental limits or improved nuclear matrix element calculations to rederive updated limits on all short-range contributions to 0 nu beta beta decay.  
  Address (up) [Gonzalez, M.; Kovalenko, S. G.] Univ Tecn Federico Santa Maria, Ctr Cient Tecnol Valparaiso, Casilla 110-V, Valparaiso 2390123, Chile, Email: marcela.gonzalezp@titulados.usm.cl;  
  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 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000368516100002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2539  
Permanent link to this record
 
 
Author Gonzalez, M.; Hirsch, M.; Kovalenko, S.G. url  doi
openurl 
  Title Neutrinoless double beta decay and QCD running at low energy scales Type Journal Article
  Year 2018 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 97 Issue 11 Pages 115005 - 6pp  
  Keywords  
  Abstract There is a common belief that the main uncertainties in the theoretical analysis of neutrinoless double beta (0 nu beta beta) decay originate from the nuclear matrix elements. Here, we uncover another previously overlooked source of potentially large uncertainties stemming from nonperturbative QCD effects. Recently perturbative QCD corrections have been calculated for all dimension 6 and 9 effective operators describing 0 nu beta beta-decay and their importance for a reliable treatment of 0 nu beta beta-decay has been demonstrated. However, these perturbative results are valid at energy scales above similar to 1 GeV, while the typical 0 nu beta beta scale is about similar to 100 MeV. In view of this fact we examine the possibility of extrapolating the perturbative results towards sub-GeV nonperturbative scales on the basis of the QCD coupling constant “freezing” behavior using background perturbation theory. Our analysis suggests that such an infrared extrapolation does modify the perturbative results for both short-range and long-range mechanisms of 0 nu beta beta-decay in general only moderately. We also discuss that the tensor circle times tensor effective operator cannot appear alone in the low energy limit of any renormalizable high-scale model and then demonstrate that all five linearly independent combinations of the scalar and tensor operators, which can appear in renormalizable models, are infrared stable.  
  Address (up) [Gonzalez, M.; Kovalenko, S. G.] Univ Tecn Federico Santa Maria, Ctr Cient Tecnol Valparaiso, Casilla 110-V, Valparaiso 2390123, Chile, Email: marcela.gonzalezp@usm.cl;  
  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:000434211200008 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3603  
Permanent link to this record
 
 
Author Helo, J.C.; Kovalenko, S.G.; Hirsch, M.; Pas, H. url  doi
openurl 
  Title Neutrinoless double beta decay and lepton number violation at the LHC Type Journal Article
  Year 2013 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 88 Issue 1 Pages 011901 - 5pp  
  Keywords  
  Abstract We compare the discovery potential of the LHC for lepton number violating (LNV) signals with the sensitivity of current and future double beta decay experiments, assuming 0 nu beta beta decay is dominated by heavy particle exchange. We consider charged scalar, leptoquark and diquark mechanisms of 0 nu beta beta decay, covering the 0 nu beta beta decay operators with both, the smallest and largest, possible rates. We demonstrate, if 0 nu beta beta decay were found with a half-life below 10(26)-10(27) years a positive signal should show up at the LHC, except for some particular cases of the leptoquark mechanism, and vice versa, if the LHC does not find any hints for LNV, a “short-range” explanation for a finite 0 nu beta beta decay half-life will be ruled out in most cases. We argue, if a positive LNV signal were found at the LHC, it is possible to identify the dominant contribution to 0 nu beta beta. Two different kinds of observables which could provide such “model discriminating” power are discussed: different invariant mass peaks and the charge asymmetry.  
  Address (up) [Helo, J. C.; Kovalenko, S. G.] Univ Tecn Federico Santa Maria, Ctr Cient Tecnol Valparaiso, Valparaiso, Chile, Email: juan.heloherrera@gmail.com;  
  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 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000322225900001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1523  
Permanent link to this record
 
 
Author Helo, J.C.; Kovalenko, S.G.; Hirsch, M.; Pas, H. url  doi
openurl 
  Title Short-range mechanisms of neutrinoless double beta decay at the LHC Type Journal Article
  Year 2013 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 88 Issue 7 Pages 073011 - 19pp  
  Keywords  
  Abstract Lepton number violation (LNV) mediated by short- range operators can manifest itself in both neutrinoless double beta decay (0 nu beta beta) and in processes with same- sign dilepton final states at the LHC. We derive limits from existing LHC data at root s = 8 TeV and compare the discovery potential of the forthcoming root s = 14 TeV phase of the LHC with the sensitivity of current and future 0 nu beta beta decay experiments, assuming the short-range part of the 0 nu beta beta decay amplitude dominates. We focus on the first of two possible topologies triggered by one fermion and two bosons in the intermediate state. In all cases, except for the pure leptoquark mechanism, the LHC will be more sensitive than 0 nu beta beta decay in the future. In addition, we propose to search for a charge asymmetry in the final state leptons and to use different invariant mass peaks as a possible tool to discriminate the various possible mechanisms for LNV signals at the LHC.  
  Address (up) [Helo, J. C.; Kovalenko, S. G.] Univ Tecn Federico Santa Maria, Ctr Cient Tecnol Valparaiso, Valparaiso, Chile, Email: juan.heloherrera@gmail.com;  
  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 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000326111000002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1627  
Permanent link to this record
 
 
Author Helo, J.C.; Kovalenko, S.G.; Hirsch, M. url  doi
openurl 
  Title Heavy neutrino searches at the LHC with displaced vertices Type Journal Article
  Year 2014 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 89 Issue 7 Pages 073005 - 7pp  
  Keywords  
  Abstract Sterile neutrinos with masses in the range of 1-100 GeV have been searched for in a variety of experiments. Here, we discuss the prospects of searching for sterile neutrinos at the LHC using displaced vertices. Two different cases are discussed: (i) the standard model extended with sterile neutrinos, and (ii) right-handed neutrinos in a left-right symmetric extension of the standard model. A dedicated displaced vertex search will allow us to probe parts of the parameter space not accessible to other searches, but both cases will require a large luminosity.  
  Address (up) [Helo, J. C.; Kovalenko, S. G.] Univ Tecn Federico Santa Maria, Ctr Cient Tecnol Valparaiso, Valparaiso, Chile, Email: juancarlos.helo@usm.cl;  
  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 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000334314500002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1756  
Permanent link to this record
 
 
Author Helo, J.C.; Hirsch, M.; Ota, T. url  doi
openurl 
  Title Long-range contributions to double beta decay revisited Type Journal Article
  Year 2016 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 06 Issue 6 Pages 006 - 32pp  
  Keywords Beyond Standard Model; Neutrino Physics  
  Abstract We discuss the systematic decomposition of all dimension-7 (d = 7) lepton number violating operators. These d = 7 operators produce momentum enhanced contributions to the long-range part of the 0 nu beta beta decay amplitude and thus are severely constrained by existing half-live limits. In our list of possible models one can find contributions to the long-range amplitude discussed previously in the literature, such as the left-right symmetric model or scalar leptoquarks, as well as some new models not considered before. The d = 7 operators generate Majorana neutrino mass terms either at tree-level, 1-loop or 2-loop level. We systematically compare constraints derived from the mass mechanism to those derived from the long-range 0 nu beta beta decay amplitude and classify our list of models accordingly. We also study one particular example decomposition, which produces neutrino masses at 2-loop level, can fit oscillation data and yields a large contribution to the long-range 0 nu beta beta decay amplitude, in some detail.  
  Address (up) [Helo, J. C.] Univ Tecn Federico Santa Maria, Ctr Cient Tecnol Valparaiso, Casilla 110-5, Valparaiso, Chile, Email: juancarlos.helo@usm.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:000377413400001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2721  
Permanent link to this record
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