• 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 ...
    • Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced in 36 fb−1 of pp collisions at s√=13 TeV 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, 2018-01-12)
      A search for heavy neutral Higgs bosons and Z′ bosons is performed using a data sample corresponding to an integrated luminosity of 36.1 fb^−1 from proton-proton collisions at √s=13 TeV recorded by the ATLAS detector at ...
    • Search for anomalous production of prompt same-sign lepton pairs and pair-produced doubly charged Higgs bosons with \(\sqrt{s}\) = 8 TeV \(pp\) collisions using the ATLAS detector 

      Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdel Khalek, Samah; Abdinov, Ovsat Bahram oglu; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Hass; Abramowicz, Halina; Buanes, Trygve; Dale, Ørjan; Eigen, Gerald; Kastanas, Alex; Liebig, Wolfgang; Lipniacka, Anna; Martin dit Latour, Bertrand; Rosendahl, Peter Lundgaard; Sandaker, Heidi; Sjursen, Therese B.; Smestad, Lillian; Stugu, Bjarne; Ugland, Maren; Bugge, Lars; Bugge, Magnar Kopangen; Cameron, David Gordon; Catmore, James Richard; Czyczula, Zofia; Franconi, Laura; Gjelsten, Børge Kile; Gramstad, Eirik; Ould-Saada, Farid; Pajchel, Katarina; Pedersen, Maiken; Read, Alexander Lincoln; Røhne, Ole Myren; Stapnes, Steinar; Strandlie, Are; Abreu, Henso; Abreu, Rômulo F.; Abulaiti, Yiming; Acharya, Bobby S.; Adamczyk, Leszek; Adams, David; Adelman, Jareed; Adomeit, Stefanie; Adye, Tim; Agatonovic-Jovin, Tatjana; Aguilar Saavedra, Juan Antonio; Agustoni, Marco; ATLAS, Collaboration (Peer reviewed; Journal article, 2015-03-09)
      A low-background inclusive search for new physics in events with same-sign dileptons is presented. The search uses proton--proton collisions corresponding to 20.3 fb\(^{-1}\) of integrated luminosity taken in 2012 at a ...
    • Search for heavy resonances decaying into a W or Z boson and a Higgs boson in final states with leptons and b-jets in 36 fb−1 of √s=13 TeV pp collisions 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, 2018-03-28)
      A search is conducted for new resonances decaying into a W or Z boson and a 125 GeV Higgs boson in the 𝜈𝜈⎯⎯⎯𝑏𝑏⎯⎯⎯ , ℓ±𝜈𝑏𝑏⎯⎯⎯ , and ℓ+ℓ−𝑏𝑏⎯⎯⎯ final states, where ℓ± = e± or μ±, in pp collisions at 𝑠√=13 TeV. The ...
    • Search for Higgs boson decays to beyond-the-Standard-Model light bosons in four-lepton events with the ATLAS detector at √s=13 TeV 

      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; Nilsen, Jon Kerr; 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; ATLAS, Collaboration (Peer reviewed; Journal article, 2018-06-29)
      A search is conducted for a beyond-the-Standard-Model boson using events where a Higgs boson with mass 125 GeV decays to four leptons (ℓ = e or μ). This decay is presumed to occur via an intermediate state which contains ...
    • Search for pair production of up-type vector-like quarks and for four-top-quark events in final states with multiple b-jets 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; Fomin, Nikolai; 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; Gramstad, Eirik; Hellesund, Simen; Morisbak, Vanja; Oppen, Henrik; Ould-Saada, Farid; Read, Alexander Lincoln; Røhne, Ole Myren; Sandaker, Heidi; Serfon, Cédric; Stapnes, Steinar; Vadla, Knut Oddvar Høie; Abulaiti, Yiming; Acharya, Bobby S.; Adachi, Shunsuke; Adamczyk, Leszek; Adelman, Jareed; Adersberger, Michael; Adye, Tim; Affolder, Anthony Allen; Afik, Yoav; Agheorghiesei, Catalin; Aguilar Saavedra, Juan Antonio; Ahmadov, Faig; Aielli, Giulio; ATLAS, Collaboration (Peer reviewed; Journal article, 2018-07-12)
      A search for pair production of up-type vector-like quarks (T ) with a significant branching ratio into a top quark and either a Standard Model Higgs boson or a Z boson is presented. The same analysis is also used to search ...
    • Search for supersymmetry in events with large missing transverse momentum, jets, and at least one tau lepton in 20 fb−1 of √s = 8 TeV proton-proton collision data with the ATLAS detector 

      Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdel Khalek, Samah; Abdinov, Ovsat Bahram oglu; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Hass; Abramowicz, Halina; Buanes, Trygve; Dale, Ørjan; Eigen, Gerald; Kastanas, Alex; Liebig, Wolfgang; Lipniacka, Anna; Martin dit Latour, Bertrand; Rosendahl, Peter Lundgaard; Sandaker, Heidi; Sjursen, Therese B.; Smestad, Lillian; Stugu, Bjarne; Ugland, Maren; Bugge, Lars; Bugge, Magnar Kopangen; Cameron, David Gordon; Catmore, James Richard; Czyczula, Zofia; Franconi, Laura; Gjelsten, Børge Kile; Gramstad, Eirik; Ould-Saada, Farid; Pajchel, Katarina; Pedersen, Maiken; Read, Alexander Lincoln; Røhne, Ole Myren; Stapnes, Steinar; Strandlie, Are; Abreu, Henso; Adamczyk, Leszek; Adams, David; Adelman, Jareed; Adomeit, Stefanie; Adye, Tim; Agatonovic-Jovin, Tatjana; Aguilar Saavedra, Juan Antonio; Agustoni, Marco; Ahlen, Steven; Åkerstedt, Henrik; Åkesson, Torsten P.A.; ATLAS, Collaboration (Peer reviewed; Journal article, 2014-09-18)
      A search for supersymmetry (SUSY) in events with large missing transverse momentum, jets, at least one hadronically decaying tau lepton and zero or one additional light leptons (electron/muon), has been performed using ...
    • Searches for heavy ZZ and ZW resonances in the ℓℓqq and ννqq final states in pp collisions at √s=13TeV 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; Nilsen, Jon Kerr; 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; ATLAS, Collaboration (Peer reviewed; Journal article, 2018-03-05)
      This paper reports searches for heavy resonances decaying into ZZ or ZW using data from proton-proton collisions at a centre-of-mass energy of √s=13 TeV. The data, corresponding to an integrated luminosity of 36.1 fb^−1, ...
    • 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 ...
    • Supersymmetric Cascade Decays at the LHC 

      Raklev, Are R. (Doctoral thesis, 2007-06-04)
    • 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 ...