M. Raidal

Doubly charged Higgs at LHC

Abstract We have investigated the production of doubly charged Higgs particles Δ L , R ++ via the WW fusion process in proton-proton collisions at LHC energies in the framework of the left-right symmetric model. The production cross section of the right-triplet Higgs Δ R ++ is for representative values of the model parameters at femtobarn level. The discovery reach depends on the mass of the right-handed gauge boson W R . At best Δ R ++ masses up to 2.4 TeV are achievable within a one-year run. For Δ L ++ the corresponding limit is 1.75 TeV which depends on the value of the left-triplet vev ν L . Comparison with Drell-Yan pair production processes shows that studies of the WW fusion processes extend the discovery reach of LHC roughly by a factor of two. The main experimental signal of a produced Δ L , R ++ would be a hard same-sign lepton pair. There will be no substantial background due to the Standard Model (SM) interactions, since in the SM a same-sign lepton pair will always be associated with missing energy, i.e. neutrinos, due to lepton number conservation.We have investigated production of doubly charged Higgs particles

μ-e conversion in nuclei versus μ→e γ: an effective field theory point of view

\Delta_{L,R}^{++}

DISCOVERING AND STUDYING BILEPTONS WITH E-E- COLLISIONS

via WW fusion process in proton-proton collisions at LHC energies in the framework of the left-right symmetric model. The production cross section of the right-triplet Higgs is for representative values of model parameters at femtobarn level. The discovery reach depends on the mass of the right-handed gauge boson W_R. At best

Constraints on doubly charged Higgs interactions at linear collider

\Delta_R^{++}

Lower bounds on bilepton processes at e- e- and mu- mu- colliders

mass up to 2.4 TeV are achievable within one year run. For

Spontaneous CP violation and the B0 system

\Delta^{++}_L

Heavy neutrino mixing and single production at linear collider

the corresponding limit is 1.75 TeV which depends on the value of the left-triplet vev v_L. Comparison with Drell-Yan pair production processes shows that studies of the WW fusion processes extend the discovery reach of LHC roughly by a factor of two. The main experimental signal of a produced Higgs would be a hard same-sign lepton pair. There will be no substantial background due to the Standard Model (SM) interactions, since in the SM a same-sign lepton pair will always be associated with missing energy, i.e. neutrinos, due to lepton number conservation.

Non-decoupling and lepton number violation in left-right models

Abstract Using an effective lagrangian description we analyze possible new physics contributions to the most relevant muon number violating processes: μ→e γ and μ–e conversion in nuclei. We identify a general class of models in which those processes are generated at one loop level and in which μ–e conversion is enhanced with respect to μ→e γ by a large ln(m2μ/Λ2), where Λ is the scale responsible for the new physics. For this wide class of models bounds on μ–e conversion constrain the scale of new physics more stringently than μ→e γ already at present and, with the expected improvements in μ–e conversion experiments, will push it upwards by about one order of magnitude more. To illustrate this general result we give an explicit model containing a doubly charged scalar and derive new bounds on its couplings to the leptons.

CP asymmetries in B0 decays in the left-right model

Abstract We analyze the prospects for discovering and unraveling the nature of doubly charged bileptons at a linear collider of the next generation running in its e − e − mode. We stress the importance of initial state radiation, beam spread and polarization, and compute the discovery bounds. The gauge nature of vector bileptons can be determined by studying hard photon emission.

CPAsymmetries inB0Decays in the Left-Right Model

Abstract Production of a single doubly charged Higgs boson Δ −− in polarized e + e − and e + γ collision modes of the linear collider have been investigated. The mass range of Δ −− to be probed extends up to the collision energy. The diagonal lepton number violating Yukawa coupling h ee will be tested at least three orders of magnitude more strictly than in present experiments.