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Author Esteves, J.N.; Romao, J.C.; Hirsch, M.; Vicente, A.; Porod, W.; Staub, F. url  doi
openurl 
  Title LHC and lepton flavour violation phenomenology of a left-right extension of the MSSM Type Journal Article
  Year 2010 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 12 Issue (down) 12 Pages 077 - 44pp  
  Keywords Supersymmetry Phenomenology  
  Abstract We study the phenomenology of a supersymmetric left-right model, assuming minimal supergravity boundary conditions. Both left-right and (B-L) symmetries are broken at an energy scale close to, but significantly below the GUT scale. Neutrino data is explained via a seesaw mechanism. We calculate the RGEs for superpotential and soft parameters complete at 2-loop order. At low energies lepton flavour violation (LFV) and small, but potentially measurable mass splittings in the charged scalar lepton sector appear, due to the RGE running. Different from the supersymmetric “pure seesaw” models, both, LFV and slepton mass splittings, occur not only in the left-but also in the right slepton sector. Especially, ratios of LFV slepton decays, such as Br((tau) over bar (R) -> μchi(0)(1))/Br((tau) over bar (L) -> μchi(0)(1)) are sensitive to the ratio of (B-L) and left-right symmetry breaking scales. Also the model predicts a polarization asymmetry of the outgoing positrons in the decay mu(+) -> e(+)gamma, A similar to [0, 1], which differs from the pure seesaw “prediction” A = 1. Observation of any of these signals allows to distinguish this model from any of the three standard, pure (mSugra) seesaw setups.  
  Address [Esteves, J. N.; Romao, J. C.] Inst Super Tecn, Dept Fis, P-1049001 Lisbon, Portugal, Email: joaomest@cftp.ist.utl.pt  
  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 1126-6708 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000285964200015 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 532  
Permanent link to this record
 

 
Author Boucenna, S.M.; Celis, A.; Fuentes-Martin, J.; Vicente, A.; Virto, J. url  doi
openurl 
  Title Phenomenology of an SU(2) x SU(2) x U(1) model with lepton-flavour non-universality Type Journal Article
  Year 2016 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 12 Issue (down) 12 Pages 059 - 43pp  
  Keywords Beyond Standard Model; Gauge Symmetry  
  Abstract We investigate a gauge extension of the Standard Model in light of the observed hints of lepton universality violation in b -> clv and b -> sl(+) l(-) decays at BaBar, Belle and LHCb. The model consists of an extended gauge group SU(2)(1) x SU(2)(2) x U(l)(Y) which breaks spontaneously around the TeV scale to the electroweak gauge group. Fermion mixing effects with vector -like fermions give rise to potentially large new physics contributions in flavour transitions mediated by WI and Z' bosons. This model can ease tensions in B -physics data while satisfying stringent bounds from flavour physics, and electroweak precision data. Possible ways to test the proposed new physics scenario with upcoming experimental measurements are discussed. Among other predictions, the ratios RM =Gamma(B -> M mu(+)mu(-))/Gamma(B -> Me(+)e(-)), with M = K*, phi, are found to be reduced with respect to the Standard Model expectation R-M similar or equal to 1.  
  Address [Boucenna, Sofiane M.] Ist Nazl Fis Nucl, Lab Nazl Frascati, Via Enrico Fermi 40, I-100044 Frascati, Italy, Email: boucenna@lnf.infn.it;  
  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:000399290600001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3063  
Permanent link to this record
 

 
Author Hirsch, M.; Staub, F.; Vicente, A. url  doi
openurl 
  Title Enhancing l(i) -> 3l(j) with the Z(0)-penguin Type Journal Article
  Year 2012 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 85 Issue (down) 11 Pages 113013 - 5pp  
  Keywords  
  Abstract Lepton flavor violation has been observed in neutrino oscillations. For charged lepton flavor violation decays only upper limits are known, but sizable branching ratios are expected in many neutrino mass models. High-scale models, such as the classical supersymmetric seesaw, usually predict that decays l(i) -> 3l(j) are roughly a factor alpha smaller than the corresponding decays l(i) -> l(j)gamma. Here we demonstrate that the Z(0)-penguin diagram can give an enhancement for decays l(i) -> 3l(j) in many extensions of the minimal supersymmetric standard model (MSSM). We first discuss why the Z(0)-penguin is not dominant in the MSSM with seesaw and show that much larger contributions from the Z(0)-penguin are expected in general. We then demonstrate the effect numerically in two example models, namely, the supersymmetric inverse seesaw and R-parity violating supersymmetry.  
  Address [Hirsch, M.] Univ Valencia Edificio Inst Paterna, CSIC, AHEP Grp, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: mahirsch@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 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000305680800003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1075  
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Author Hirsch, M.; Joaquim, F.R.; Vicente, A. url  doi
openurl 
  Title Constrained SUSY seesaws with a 125 GeV Higgs Type Journal Article
  Year 2012 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 11 Issue (down) 11 Pages 105 - 33pp  
  Keywords Higgs Physics; Rare Decays; Neutrino Physics; Supersymmetric Standard Model  
  Abstract Motivated by the ATLAS and CMS discovery of a Higgs-like boson with a mass around 125 GeV, and by the need of explaining neutrino masses, we analyse the three canonical SUSY versions of the seesaw mechanism (type I, II and III) with CMSSM boundary conditions. In type II and III cases, SUSY particles are lighter than in the CMSSM (or the constrained type I seesaw), for the same set of input parameters at the universality scale. Thus, to explain m(h0) similar or equal to 125 GeV at low energies, one is forced into regions of parameter space with very large values of m(0), M-1/2 or A(0). We compare the squark and gluino masses allowed by the ATLAS and CMS ranges for m(h0) (extracted from the 2011-2012 data), and discuss the possibility of distinguishing seesaw models in view of future results on SUSY searches. In particular, we briefly comment on the discovery potential of LHC upgrades, for squark/gluino mass ranges required by present Higgs mass constraints. A discrimination between different seesaw models cannot rely on the Higgs mass data alone, therefore we also take into account the MEG upper limit on BR(mu -> e gamma) and show that, in some cases, this may help to restrict the SUSY parameter space, as well as to set complementary limits on the seesaw scale.  
  Address [Hirsch, M.] Univ Valencia, CSIC, Inst Fis Corpuscular, AHEP Grp, E-46071 Valencia, Spain, Email: mahirsch@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 1126-6708 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000312198500040 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1301  
Permanent link to this record
 

 
Author Boucenna, S.M.; Morisi, S.; Vicente, A. url  doi
openurl 
  Title LHC diphoton resonance from gauge symmetry Type Journal Article
  Year 2016 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 93 Issue (down) 11 Pages 115008 - 8pp  
  Keywords  
  Abstract Motivated by what is possibly the first sign of new physics seen at the LHC, the diphoton excess at 750 GeV in ATLAS and CMS, we present a model that provides naturally the necessary ingredients to explain the resonance. The simplest phenomenological explanation for the diphoton excess requires a new scalar state, X(750), as well as additional vectorlike (VL) fermions introduced in an ad-hoc way in order to enhance its decays into a pair of photons and/or increase its production cross section. We show that the necessary VL quarks and their couplings can emerge naturally from a complete framework based on the SU(3)(L) circle times U(1)(X) gauge symmetry.  
  Address [Boucenna, Sofiane M.] Ist Nazl Fis Nucl, Lab Nazl Frascati, CP 13, I-100044 Frascati, Italy, Email: boucenna@lnf.infn.it;  
  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:000377505700002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2717  
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