119056575
mu- tau Symmetry and Radiatively Generated Leptogenesis
We consider a $\ensuremath{\mu}\ensuremath{-}\ensuremath{\tau}$ symmetry in neutrino sectors realized at the GUT scale in the context of a seesaw model. In our scenario, the exact $\ensuremath{\mu}\ensuremath{-}\ensuremath{\tau}$ symmetry realized in the basis where the charged lepton and heavy Majorana neutrino mass matrices are diagonal leads to vanishing lepton asymmetries. We find that, in the minimal supersymmetric extension of the seesaw model with large $\mathrm{tan}﻿\ensuremath{\beta}$, the renormalization group (RG) evolution from the GUT scale to seesaw scale can induce a successful leptogenesis even without introducing any symmetry breaking terms by hand, whereas such RG effects lead to tiny deviations of ${\ensuremath{\theta}}_{23}$ and ${\ensuremath{\theta}}_{13}$ from $\ensuremath{\pi}/4$ and zero, respectively. It is shown that the right amount of the baryon asymmetry ${\ensuremath{\eta}}_{B}$ can be achieved via so-called resonant leptogenesis, which can be realized at rather low seesaw scale with large $\mathrm{tan}﻿\ensuremath{\beta}$ in our scenario so that the well-known gravitino problem is safely avoided.
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.
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.
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.
126179603
Measurement of |V(ub) / V(cb)| (and |V(ub)|) in exclusive nonleptonic decays within the generalized factorization scheme
Within the generalized factorization scheme, we study extracting $|{V}_{\mathrm{ub}}{/V}_{\mathrm{cb}}|$ by calculating the ratios $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{D}_{s}^{(*)\ensuremath{-}}({\ensuremath{\pi}}^{+},{\ensuremath{\rho}}^{+}))/\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{D}_{s}^{(*)\ensuremath{-}}{D}^{(*)+})$ including penguin effects. The ratios involving the ${B}^{0}\ensuremath{\rightarrow}{D}_{s}^{\ensuremath{-}}{D}^{+}$ mode have considerable penguin corrections $(\ensuremath{\sim}15%$ at the amplitude level), but those involving the ${B}^{0}\ensuremath{\rightarrow}{D}_{s}^{\ensuremath{-}}{D}^{*+}$ mode have relatively small penguin corrections. On the other hand, the ${B}^{0}\ensuremath{\rightarrow}{D}_{s}^{\ensuremath{-}}{D}^{+}$ mode has a smaller form-factor dependence. Therefore, these ratios complement each other in measuring ${V}_{\mathrm{ub}}{/V}_{\mathrm{cb}}.$ The theoretical uncertainty from the hadronic form factors in our method is at the level of 20%, which is comparable to the model dependence uncertainty of about 20% in the measurement of $|{V}_{\mathrm{ub}}{/V}_{\mathrm{cb}}|$ from the exclusive semileptonic B decays. Using the newest upper limit on $\stackrel{\ensuremath{\rightarrow}}{B}{D}_{s}\ensuremath{\pi}$ decay from CLEO, our method sets an upper limit $|{V}_{\mathrm{ub}}{/V}_{\mathrm{cb}}|l0.13$ which is very close to the measured values from the semileptonic B decays.
118999114
CP violation in the semileptonic B(lepton 4) (B ---> D pi lepton neutrino) decays: multi - Higgs doublet model and scalar leptoquark models
$\mathrm{CP}$ violation from physics beyond the standard model is investigated in ${B}_{l4}$ decays: $\stackrel{\ensuremath{\rightarrow}}{B}D\ensuremath{\pi}l{\overline{\ensuremath{\nu}}}_{l}.$ In the decay process, we include various excited states as intermediate states decaying to the final hadrons, $D+\ensuremath{\pi}$. We consider the semileptonic decay to a tau lepton family as well. $\mathrm{CP}$ violation is implemented through complex scalar-fermion couplings in the multi-Higgs-doublet model and scalar-leptoquark models beyond the standard model. With these complex couplings, we calculate the $\mathrm{CP}$-odd rate asymmetry and the optimal asymmetry. We find that for ${B}_{\ensuremath{\tau}4}$ decays the optimal asymmetry is sizable and can be detected at $1\ensuremath{\sigma}$ level with about ${10}^{6}\char21{}{10}^{7}B$-meson pairs, for maximally allowed values of $\mathrm{CP}$-odd parameters in those extended models.
11936862
Bootes II: Not a Dwarf Galaxy but Possibly Shed by One
We present moderately deep V I C photometry of Boötes II, obtained using the SOAR Telescope. While identified initially as an old, metal-poor, dwarf galaxy, Boötes II appears to be a moderately metal-rich globular cluster with [Fe/H] ≈ −0.7. The slope of the red giant branch suggests that [α/Fe] ≈ 0.0, and the turn-off indicates an age of 7 to 9 Gyrs, considerably younger than most globular clusters, but similar to Palomar 12. Like that object, Boötes II lies in the direction of the Sagittarius dwarf galaxy tidal stream, and, with a distance of almost 50 kpc, is probably associated with the more distant portion of the stream, as defined by Belokurov et al. (2006a).
119279392
THE RR LYRAE VARIABLES AND HORIZONTAL BRANCH OF NGC 6656 (M22)
The first calibrated broadband UBVI time-series photometry is presented for the RR Lyrae variable stars in NGC 6656 (M22), with observations spanning a range of 22 years. We have also redetermined the variability types and periods for the RR Lyrae stars identified previously by photographic observations, revising the number of fundamental-mode RR Lyrae variables (RR0) to 10 and the number of first-overtone variables (RR1) to 16. The mean periods of the RR0 and RR1 variables are (P) {sub RR0} = 0.66 ± 0.02 days and (P) {sub RR1} = 0.33 ± 0.01 days, respectively, supporting an Oosterhoff II classification for the cluster. The number ratio of RR1-type to all RR-type variables is N {sub 1}/N{sub RR} = 0.61, also consistent with an Oosterhoff II designation. Both the RR Lyrae stars' minimum light colors and the blue edge of the RR Lyrae instability strip suggest E( B – – V) = 0.36 ± 0.02 mag toward M22. Regarding the HB morphology of M22, we find (B-R)/(B+V+R) = +0.97 ± 0.1 and at least one ''gap'' located in an unusual part of the blue HB, in the middle of the so-called hot HB stars.
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.
118586941
Cornell Potential Parameters for S-wave Heavy Quarkonia
We compute derived quantities for various values of the model parameter of the Cornell potential model for the S-wave heavy quarkonia with radial quantum numbers n=1, 2, and 3. Our results can be used to determine leading and relative-order-v^2 nonrelativistic quantum chromodynamics matrix elements for S-wave charmonia and bottomonia such as psi(2S), eta_c(2S), and Upsilon(nS) for n=1, 2, and 3. These matrix elements will be essential ingredients for resumming relativistic corrections to processes involving those S-wave heavy quarkonium states.
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.