Papers by Solveig Skadhauge
Proceedings of International Workshop on Astroparticle and High Energy Physics — PoS(AHEP2003), 2003
Physical Review D, 2004
Recently Babu, Ma and Valle proposed a model of quark and lepton mixing based on A 4 symmetry[1].... more Recently Babu, Ma and Valle proposed a model of quark and lepton mixing based on A 4 symmetry[1]. Within this model the lepton and slepton mixings are intimately related. We perform a numerical study in order to derive the slepton masses and mixings in agreement with present data from neutrino physics. We show that, starting from threefold degeneracy of the neutrino masses at a high energy scale, a viable low energy neutrino mass matrix can indeed be obtained in agreement with constraints on lepton flavour violating µ and τ decays. The resulting slepton spectrum must necessarily include at least one mass below 200 GeV which can be produced at the LHC. The predictions for the absolute Majorana neutrino mass scale m 0 ≥ 0.3 eV ensure that the model will be tested by future cosmological tests and ββ 0ν searches. Rates for lepton flavour violating processes ℓ j → ℓ i + γ in the range of sensitivity of current experiments are typical in the model, with BR(µ → eγ) > ∼ 10 −15 and the lower bound BR(τ → µγ) > 10 −9. To first approximation, the model leads to maximal leptonic CP violation in neutrino oscillations.
We investigate the three-neutrino mixing scheme for solving the atmospheric and LSND anomalies. W... more We investigate the three-neutrino mixing scheme for solving the atmospheric and LSND anomalies. We find the region in the parameter space that provides a good fit to the LSND and the SK atmospheric data, taking into account the CHOOZ constraint. We demonstrate that the goodness of this fit is comparable to that of the conventional fit to the solar and atmospheric data. Large values of the LSND angle are favoured and sin^2(2θ_ LSND) can be as high as 0.1. This can have important effects on the atmospheric electron neutrino ratios as well as on down-going multi-GeV muon neutrino ratios. We examine the possibility of distinguishing this scheme from the conventional one at the long baseline experiments. We find that the number of electron neutrino events observed at the CERN to Gran Sasso experiment may lead us to identify the scheme, and hence the mass pattern of neutrinos.
The compatibility of producing the observed amount of dark matter, as indicated by the WMAP data,... more The compatibility of producing the observed amount of dark matter, as indicated by the WMAP data, through the relic abundance of neutralinos with Yukawa unification and with the measured rate of b→ s γ is analyzed in mSUGRA and extended SUGRA unified models with the inclusion of CP phases. The CP phases affect the analysis in several ways, e.g., through the threshold corrections to the b-quark mass, via their effects on the neutralino relic density and through the SUSY contribution to the BR(b→ s γ) which is sensitive to the CP phases. We present some specific models with large SUSY phases, which can accommodate the fermion electric dipole moment constraints and give a neutralino relic density in agreement with observations as well as with the b-τ unification constraint. The possibility of achieving WMAP relic density constraints with full Yukawa unification is also explored.
An analysis of the sensitivity of supersymmetric dark matter to variations in the b quark mass is... more An analysis of the sensitivity of supersymmetric dark matter to variations in the b quark mass is given. Specifically we study the effects on the neutralino relic abundance from supersymmetric loop corrections to the mass of the b quark. It is known that these loop corrections can become significant for large tanβ. The analysis is carried out in the framework of mSUGRA and we focus on the region where the relic density constraints are satisfied by resonant annihilation through the s-channel Higgs poles. We extend the analysis to include CP phases taking into account the mixing of the CP-even and CP-odd Higgs boson states which play an important role in determining the relic density. Implications of the analysis for the neutralino relic density consistent with the recent WMAP relic density constraints are discussed.
We investigate the sensitivity of some of the proposed next-generation neutrino experiments to a ... more We investigate the sensitivity of some of the proposed next-generation neutrino experiments to a galactic supernova. In particular, we study how well the supernova parameters (the average energies and luminosities) can be separated from the unknown neutrino oscillation parameters (θ13 and the neutrino mass hierarchy). Three types of experiments, all in the megaton class, are compared. These are: a 540 kton water-Cherenkov detector, a 100 kton liquid Argon detector and a 50 kton scintillator detector. We demonstrate that practically all of these proposed detectors have the possibility to determine the hierarchy of the neutrino masses if the angle of θ13 is sufficiently large (sin 2 (θ13)> ∼ 10 −4) and the hierarchy of the average energies is larger than about 20%. They can at the same time determine some of the supernova parameters well. The average energy of the νµ and ντ species can be determined within 5 % uncertainty in most of the parameter space suggested by supernova simula...
We investigate the recently suggested scheme of independent mass matrices for neutrinos and antin... more We investigate the recently suggested scheme of independent mass matrices for neutrinos and antineutrinos. Such a CPT violating scheme is able to account for all neutrino data with the three known flavors. For atmospheric neutrinos this means that it is possible to have different mass squared differences driving the oscillation for neutrinos and antineutrinos. We analyze the atmospheric and K2K data within the simplest scheme of two neutrino oscillation, neglecting electron neutrino oscillation. We find that the preferred region is close to the CPT conserving mass spectra. However the spectra with the antineutrino mass squared difference about or larger than 0.1 eV 2 and the neutrino mass squared difference about 2 × 10 −3 eV 2 is not significantly disfavored. In this parameter region the atmospheric data are independent of the antineutrino mass squared difference. Therefore no useful constraint can be put on CPT violation effects contributing to different masses for the neutrinos and antineutrinos.
CERN-TH/2001-141 FERMILAB-Pub-01/078-T MPI-PhT/2001-15 Lund-Mph-01/02 Combining LSND and Atmospheric Anomalies in a Three-Neutrino Picture
We investigate the three-neutrino mixing scheme for solving the atmospheric and LSND anomalies. W... more We investigate the three-neutrino mixing scheme for solving the atmospheric and LSND anomalies. We find the region in the parameter space that provides a good fit to the LSND and the SK atmospheric data, taking into account the CHOOZ constraint. We demonstrate that the goodness of this fit is comparable to that of the conventional fit to the solar and atmospheric data. Large values of the LSND angle are favoured and sin 2 (2θLSND) can be as high as 0.1. This can have important effects on the atmospheric electron neutrino ratios as well as on down-going multi-GeV muon neutrino ratios. We examine the possibility of distinguishing this scheme from the conventional one at the long baseline experiments. We find that the number of electron neutrino events observed at the CERN to Gran Sasso experiment may lead us to identify the scheme, and hence the mass pattern of neutrinos. 1
We investigate the three-neutrino mixing scheme for solving the atmospheric and LSND anomalies. W... more We investigate the three-neutrino mixing scheme for solving the atmospheric and LSND anomalies. We find the region in the parameter space that provides a good fit to the LSND and the SK atmospheric data, taking into account the CHOOZ constraint. We demonstrate that the goodness of this fit is comparable to that of the conventional fit to the solar and atmospheric data. Large values of the LSND angle are favoured and sin 2 (2θ LSND) can be as high as 0.1. This can have important effects on the atmospheric electron neutrino ratios as well as on down-going multi-GeV muon neutrino ratios. We examine the possibility of distinguishing this scheme from the conventional one at the long baseline experiments. We find that the number of electron neutrino events observed at the CERN to Gran Sasso experiment may lead us to identify the scheme, and hence the mass pattern of neutrinos.
It is shown that the bi-maximal solution is the only possibility to reconcile Zee-type neutrino m... more It is shown that the bi-maximal solution is the only possibility to reconcile Zee-type neutrino mass matrix with three flavors to the current atmospheric and solar neutrino experimental data. The mass of the lightest neutrino, which consist mostly of νµ and ντ, is ≃ ∆m2 ⊙ /(2 ∆m2 atm). The related topics on Zee-type neutrino mass matrix are also discussed. 1
Fundamental properties of neutrinos: masses and mixings
Neutrino physics is one of the fastest growing topic in phenomenological high energy physics. Neu... more Neutrino physics is one of the fastest growing topic in phenomenological high energy physics. Neutrinos are elementary neutral particles and participate only in the weak interactions. For this reason it is very difficult to detect them experimentally. Nevertheless, much experimental progress has been obtained in the recent years. In particular our knowledge of the neutrino masses and mixing angles have increased, though there are still ambiguities. There are three experimental hints that neutrinos are massive. The most solid evidence come from studies of atmospheric neutrinos. Furthermore investigations of solar neutrinos as well as the accelerator experiment LSND gives hints of massive neutrinos. These three so-called anomalies cannot be reconciled with the standard scenario of three light neutrinos and it is conventional to disbelieve the LSND data. Therefore at present we are very certain that neutrinos are indeed massive and do mix, but more experimental information is needed. T...
It is shown that the bi-maximal solution is the only possibility to reconcile Zee-type neutrino m... more It is shown that the bi-maximal solution is the only possibility to reconcile Zee-type neutrino mass matrix with three flavors to the current atmospheric and solar neutrino experimental data. The mass of the lightest neutrino, which consist mostly of νμ and ντ , is ≃ ∆m2⊙/(2 √ ∆matm). The related topics on Zee-type neutrino mass matrix are also discussed. E-mail address:mmatsuda@auecc.aichi-edu.ac.jp E-mail address:ceja@matfys.lth.se E-mail address:solveig@matfys.lth.se E-mail address:tanimoto@muse.hep.sc.niigata-u.ac.jp
We investigate a neutrino mass model in which the neutrino data is accounted for by bilinear R– p... more We investigate a neutrino mass model in which the neutrino data is accounted for by bilinear R– parity violating supersymmetry with anomaly mediated supersymmetry breaking. We focus on the CERN Large Hadron Collider (LHC) phenomenology, studying the reach of generic supersymmetry search channels with leptons, missing energy and jets. A special feature of this model is the existence of long lived neutralinos and charginos which decay inside the detector leading to detached vertices. We demonstrate that the largest reach is obtained in the displaced vertices channel and that practically all of the reasonable parameter space will be covered with an integrated luminosity of 10 fb−1. We also compare the displaced vertex reaches of the LHC and Tevatron. Electronic address: camposc@feg.unesp.br Electronic address: mad@susy.fis.puc.cl Electronic address: eboli@fma.if.usp.br Electronic address: magro@fma.if.usp.br Electronic address: porod@physik.uni-wuerzburg.de Electronic address: solveig@...
Phys Rev D, 2006
Our analysis takes account of the full allowed set of twenty one-loop diagrams and is more genera... more Our analysis takes account of the full allowed set of twenty one-loop diagrams and is more general since it also includes the full dependence on CP phases in non universal sugra and MSSM models. A numerical analysis is carried out to estimate the size of the corrections to $b\to s+\gamma$. We also briefly discuss the implications of these results for the search for supersymmetry.
Bottom mass, Unified Models and SUSY phases
AIP Conference Proceedings, 2009
ABSTRACT The compatibility of producing the observed amount of dark matter, as indicated by the W... more ABSTRACT The compatibility of producing the observed amount of dark matter, as indicated by the WMAP data, through the relic abundance of neutralinos with Yukawa unification and with the measured rate of b-->sgamma is analyzed in extended SUGRA unified models with the inclusion of CP phases.
The Identification of Dark Matter, 2005
We extend the commonly used mSUGRA framework to allow complex soft terms. We show how these phase... more We extend the commonly used mSUGRA framework to allow complex soft terms. We show how these phases can induce large changes of the SUSY threshold corrections to the b quark mass and affect the neutralino relic density predictions of the model. We present some specific models with large SUSY phases which can accommodate the fermion electric dipole moment constraints and a neutralino relic density within the WMAP bounds.
Physical Review D
An improved analysis of the b -> s+gamma decay in the minimal flavor violating case is given t... more An improved analysis of the b -> s+gamma decay in the minimal flavor violating case is given taking into account additional contributions in the supersymmetric sector which enter in the next-to-leading-order (NLO) and are enhanced by tan beta factors. Specifically, we compute a set of 20 one-loop diagrams to give the most complete analysis to date of the NLO supersymmetric corrections. These modifications are computed from the effective charged Higgs and neutral Higgs couplings involving 12 loop diagrams for the charged Higgs sector and eight loop diagrams for the neutral Higgs sector. While the computations of these corrections are available in the literature, their full forms including the complex phase dependence has not be considered. Our analysis takes account of the full allowed set of 20 one-loop diagrams and is more general since it also includes the full dependence on CP phases in non universal SUGRA and MSSM models. A numerical analysis is carried out to estimate the si...
It is shown that the bi-maximal solution is the only possibility to reconcile Zee-type neutrino m... more It is shown that the bi-maximal solution is the only possibility to reconcile Zee-type neutrino mass matrix with three flavors to the current atmospheric and solar neutrino experimental data. The mass of the lightest neutrino, which consist mostly of �µ and ��, is ≃ �m2⊙/(2 q �m2atm). The related topics on Zee-type neutrino mass matrix are also discussed.
Uploads
Papers by Solveig Skadhauge