• CP-Violation in the \(ZZZ\) and \(ZWW\) vertices at \(e^+e^-\) colliders in Two-Higgs-Doublet Models 

      Grzadkowski, Bohdan; Øgreid, Odd Magne; Osland, Per (Peer reviewed; Journal article, 2016-05)
      We discuss possibilities of measuring CP violation in the Two-Higgs-Doublet Model by studying effects of one-loop generated \(ZZZ\) and \(ZWW\) vertices. We discuss a set of CP-sensitive asymmetries for \(ZZ\) and \(W^+W^-\) ...
    • Diagnosing CP properties of the 2HDM 

      Grzadkowski, Bohdan; Øgreid, Odd Magne; Osland, Per (Peer reviewed; Journal article, 2014-01)
      We have investigated a Two-Higgs-Doublet Model (2HDM), focusing on CP violation. Various scenarios with spontaneous and explicit breaking of CP have been considered. Some features of CP violation related to a choice of the ...
    • Exploring the CP-violating Inert-Doublet Model 

      Grzadkowski, B.; Ogreid, Odd Magne; Osland, Per; Pukhov, A.; Poormohammadi, Mahdi (Peer reviewed; Journal article, 2011-06-01)
      We have explored properties of an extension of the Inert Doublet Model by the addition of an extra non-inert scalar doublet. The model offers a possibility of CP violation in the scalar sector and a candidate for the Dark ...
    • Heavy Higgs boson decays in the alignment limit of the 2HDM 

      Øgreid, Odd Magne; Osland, Per; Grzadkowski, Bohdan; Haber, Howard (Peer reviewed; Journal article, 2018-12)
      The Standard Model (SM)-like couplings of the observed Higgs boson impose strong constraints on the structure of any extended Higgs sector. We consider the theoretical properties and the phenomenological implications of a ...
    • Measuring CP violation in two-Higgs-doublet models in light of the LHC Higgs data 

      Grzadkowski, Bohdan; Øgreid, Odd Magne; Osland, Per (Peer reviewed; Journal article, 2014-11)
      In Two-Higgs-Doublet models, the conditions for CP violation can be ex- pressed in terms of invariants under U(2) rotations among the two SU(2) Higgs doublet fields. In order to design a strategy for measuring the invariants ...
    • Probing the charged Higgs boson at the LHC in the CP-violating type-II 2HDM 

      Basso, L.; Lipniacka, Anna; Moretti, S.; Osland, Per; Pruna, G. M.; Poormohammadi, Mahdi (Peer reviewed; Journal article, 2012-11-05)
      We present a phenomenological study of a CP-violating two-Higgs-doublet Model with type-II Yukawa couplings at the Large Hadron Collider (LHC). In the light of recent LHC data, we focus on the parameter space that survives ...
    • Properties of S3-Symmetric Three-Higgs-Doublet Models 

      Kuncinas, Anton (Master thesis, 2019-06-27)
      Some aspects of the S3-symmetric three-Higgs-doublet models are analysed. A CP conserving potential with both real and complex vacuum configurations is considered. The S3-symmetric potential is presented in the irreducible ...
    • SearchSearch for exclusive Higgs and Z boson decays to ϕγ and ργ with the ATLAS detector for exclusive Higgs and Z boson decays to ϕγ and ργ with the ATLAS detector 

      Aaboud, Morad; Aad, Georges; Abbott, Brad; Abdinov, Ovsat Bahram oglu; Abeloos, Baptiste; Abidi, Syed Haider; AbouZeid, Hass; Abraham, Nadine L.; Abramowicz, Halina; Abreu, Henso; Buanes, Trygve; Dale, Ørjan; Eigen, Gerald; Liebig, Wolfgang; Lipniacka, Anna; Martin dit Latour, Bertrand; Mæland, Steffen; Stugu, Bjarne; Yang, Zongchang; Zalieckas, Justas; Bugge, Magnar Kopangen; Cameron, David Gordon; Catmore, James Richard; Feigl, Simon; Franconi, Laura; Garonne, Vincent; Gjelsten, Børge Kile; Gramstad, Eirik; Morisbak, Vanja; Oppen, Henrik; Ould-Saada, Farid; Raddum, Silje Hattrem; Read, Alexander Lincoln; Røhne, Ole Myren; Sandaker, Heidi; Serfon, Cédric; Stapnes, Steinar; Vadla, Knut Oddvar Høie; Abreu, Rômulo F.; Abulaiti, Yiming; Acharya, Bobby S.; Adachi, Shunsuke; Adamczyk, Leszek; Adelman, Jareed; Adersberger, Michael; Adye, Tim; Affolder, Anthony Allen; Afik, Yoav; Agatonovic-Jovin, Tatjana; Agheorghiesei, Catalin; ATLAS, Collaboration (Peer reviewed; Journal article, 2018-07-19)
      A search for the exclusive decays of the Higgs and Z bosons to a ϕ or ρ meson and a photon is performed with a pp collision data sample corresponding to an integrated luminosity of up to 35.6 fb−1 collected at 𝑠√=13 TeV ...
    • A simple method to detect spontaneous CP violation in multi-Higgs models 

      Øgreid, Odd Magne; Osland, Per; Rebelo, Margarida N. (Peer reviewed; Journal article, 2017-08)
      For models with several Higgs doublets we present an alternative method to the one proposed by Branco, Gerard and Grimus, in 1984, to check whether or not CP is spontaneously violated in the Higgs potential. The previous ...
    • Spontaneous symmetry breaking in the S3-symmetric scalar sector 

      Emmanuel-Costa, David; Øgreid, Odd Magne; Osland, Per; Rebelo, Margarida N. (Peer reviewed; Journal article, 2016-02)
      We present a detailed study of the vacua of the S3-symmetric three-Higgs-doublet potential, specifying the region of parameters where these minimisation solutions occur. We work with a CP conserving scalar potential and ...
    • Symmetries and mass degeneracies in the scalar sector 

      Haber, Howard E.; Øgreid, Odd Magne; Osland, Per; Rebelo, Margarida N. (Peer reviewed; Journal article, 2019-01-04)
      We explore some aspects of models with two and three SU(2) scalar doublets that lead to mass degeneracies among some of the physical scalars. In Higgs sectors with two scalar doublets, the exact degeneracy of scalar masses, ...
    • Symmetry and mass degeneration in multi-Higgs-doublet models 

      Olaussen, Kåre; Osland, Per; Solberg, Marius Aase (Peer reviewed; Journal article, 2011-07-05)
      We investigate possible symmetry properties of the scalar sector of Multi-Higgs-Doublet Models, and, to some extent, the generalization of such models to gauge groups other than SU(2)_L  × U(1)_Y . In models with C (charge ...