118116913
Phased breaking of -t symmetry and leptogenesis
Nonvanishing U{sub e3} has been theoretically related to a certain flavor symmetry breaking in the neutrino sector. We propose a scenario to break the {mu}-{tau} symmetry so as to accommodate the nonvanishing U{sub e3}. Our scenario is constructed in the context of a seesaw model, and the {mu}-{tau} symmetry breaking is achieved by introducing a CP phase in the Dirac Yukawa matrix. We also show how the deviation of {theta}{sub 23} from the maximal mixing and nonvanishing U{sub e3} depend on the CP phase. Neutrino mixings and the neutrino mass-squared differences are discussed, and the amplitude in neutrinoless double beta decay m{sub ee} are also predicted. We found that a tiny breaking of the {mu}-{tau} symmetry due to mass splitting between two degenerate heavy Majorana neutrinos on top of the Dirac CP phase can lead to successful leptogenesis. We examine how leptogenesis can be related with low energy neutrino measurement, and show that our predictions for U{sub e3} and m{sub ee} can be constrained by the current observation of baryon asymmetry.
6266850
Systematic Investigation of Possibilities for New Physics Effects in b → s Penguin Processes
Although recent experimental results in b → s penguin process seem to be roughly consistent with the standard model predictions, there may be still large possibilities of new physics hiding in these processes. Therefore, here we investigate systematically the potential new physics effects that may appear in time-dependent CP asymmetries of B → φK 0 , B → η � K 0 and B → K 0 π 0 decay modes, by classifying the cases for the values of the mixinginduced indirect CP asymmetries, SφK0 ,S ηK0 ,S K0π0 which are compared to SJ/ψK0 .W e also show that several Bs decay modes may help to resolve the ambiguities in such an analysis. Through combining analysis with the time-dependent CP asymmetries of Bs decay modes such as Bs → φη � , Bs → η � π 0 and Bs → K 0 K 0
209866467
CP violation in the Cabibbo suppressed decay tau ---> K pi tau-neutrino with polarized tau leptons
118146740
The intrinsic and oscillated astrophysical neutrino flavor ratios
The pp interactions taking place in the cosmos around us are a source of the astrophysical neutrinos of all the three flavors. In these interactions, the electron and the muon neutrinos mainly come from the production and the decay of the \pi^{\pm} mesons, whereas the tau neutrinos mainly come from the production and the decay of the D^{\pm}_{S} mesons. We estimate the three intrinsic neutrino flavor ratios for 1 GeV 10^{-10} in the presence of neutrino oscillations, where L is the distance to the astrophysical neutrino source in units of parsecs.
118428627
Leptogenesis in a seesaw model with Fritzsch-type lepton mass matrices
We investigate how the baryon asymmetry of our Universe via leptogenesis can be achieved within the framework of the seesaw model with Fritzsch-type lepton mass matrices proposed by Fukugita et al. We study the cases with $CP$-violating phases in charged-lepton Yukawa matrix, however, with and without Dirac neutrino Yukawa phases. We consider both flavor-independent and flavor-dependent leptogenesis, and demonstrate how they lead to different amounts of lepton asymmetries in detail. In particular, it is shown that flavor-dependent leptogenesis in this model can be achieved only for very tiny or zero values of $CP$ phases in Dirac neutrino Yukawa matrix at the grand unified theory scale. In addition to the $CP$ phases, for successful leptogenesis in the model it is required that the degeneracy of the heavy Majorana neutrino mass spectrum should be broken and we also show that the breakdown of the degeneracy can be radiatively induced.
867013
Quark-Lepton Complementarity with Renormalization Effects through Threshold Corrections
The recent experimental measurements of the solar neutrino mixing angle θ sol and the Cabibbo mixing angle θ C reveal a surprising relation, θ sol+ θ C ’ π 4 . While this empirical relation has been interpreted as a support of the idea of grand unification, it may be merely accidental in the sense that reproducing the relation at a low energy in the framework of grand unification may depend strongly on the renormalization effects whose size can vary with the choice of parameter space. We note that the lepton mixing matrix derived from quark-lepton unification can lead to a shift of the complementarity relation at low energy. While the renormalization group effects generally lead to additive contribution on top of the shift, we show that the threshold corrections which may exist in some intermediate scale new physics such as supersymmetric standard model can diminish it, so we can achieve the complementarity relation at a low energy.
15138730
Reconstructing the Higgs boson in dileptonic W decays at hadron colliders
We examine the prospect to measure the Higgs boson mass using the recently introduced kinematic variable, the ${M}_{T2}$-assisted on-shell (MAOS) momentum, that provides a systematic approximation to the invisible neutrino momenta in dileptonic decays of a $W$-boson pair. For this purpose, we introduce a modified version of the MAOS momentum that is applicable even when one or both of the $W$-bosons from the Higgs decay are in off shell. It is demonstrated that the MAOS Higgs mass distribution, constructed with the MAOS neutrino momenta, shows a clear peak at the true Higgs boson mass when an event cut selecting higher value of ${M}_{T2}$ is employed. We perform the likelihood analysis for this MAOS mass distribution to determine the Higgs boson mass, and find it can improve the accuracy of the Higgs mass measurement. Our results indicate that the MAOS Higgs mass can also be useful for the discovery or exclusion of the Higgs boson in certain mass range.
119504141
Neutrinos in the Simplest Little Higgs Model
The simplest little Higgs model based on a SU(3) global symmetry contains a $SU(3)_{weak}$ triplet and a singlet per a generation in the lepton sector. A neutral component of the triplet and the singlet turn into a neutral vector-like $SU(2)_L$ singlet after electroweak symmetry breaking while the other neutral component of the triplet is the SM neutrino. At tree level, Yukawa couplings of the lepton sector not only allow the neutral vector-like lepton to couple to the SM neutrino, but also give them a Dirac mass. Majorana mass terms for the SM neutrinos and their partners arise at one loops, leading to neutrino flavor mixing in addition to neutrino-heavy neutral lepton mixing.
11562016
Evidence for the spin-0 nature of the Higgs boson using ATLAS data
Studies of the spin and parity quantum numbers of the Higgs boson are presented, based on protonproton collision data collected by the ATLAS experiment at the LHC. The Standard Model spin-parity J( ...
119179020
Holomorphic supersymmetric Nambu--Jona-Lasinio model with application to dynamical electroweak symmetry breaking
Based on our idea of an alternative supersymmetrization of the Nambu-Jona-Lasinio model for dynamical symmetry breaking, we analyze the resulting new model with a holomorphic dimension-five operator in the superpotential. The approach provides a new direction for modeling dynamical symmetry breaking in a supersymmetric setting. In particular, we adopt the idea to formulate a model that gives rise to the minimal supersymmetric standard model as the low energy effective theory with both Higgs superfields as composites. A renormalization group analysis is performed to establish the phenomenological viability of the scenario, with admissible background scale that could go down to the TeV scale. We give the Higgs mass range predicted.
121363109
Status of Rare Isotope Science Project in Korea
The Rare Isotope Science Project (RISP) is launched in Korea to build the IF and ISOL facilities. Current status of RISP is introduced.