122701
Robustness and predictivity of 4 TeV unification
Abstract The stability of the predictions of two of the standard model parameters, α 3 ( M Z ) and sin 2 θ ( M Z ), in a M U ∼4 TeV unification model is examined. It is concluded that varying the unification scale between M U ≃2.5 TeV and M U ≃5 TeV leaves robust all predictions within reasonable bounds. Choosing M U =3.8±0.4 TeV gives, at lowest order, accurate predictions at M Z . The impact of threshold effects on unification depends on the spectrum of states beyond the standard model.
8518266
On the determination of neutrino masses and dark energy evolution from the cross-correlation of CMB and LSS
We discuss the possibilities of the simultaneous determination of the neutrino masses and the evolution of dark energy from future cosmological observations such as cosmic microwave background (CMB), large scale structure (LSS) and the cross-correlation between them. Recently it has been discussed that there is a degeneracy between the neutrino masses and the equation of state for dark energy. It is also known that there are some degeneracies among the parameters describing the dark energy evolution. We discuss the implications of these for the cross-correlation of CMB with LSS in some detail. Then we consider to what extent we can determine the neutrino masses and the dark energy evolution using the expected data from CMB, LSS and their cross-correlation.
14635411
Bigger Rip with no dark energy
Abstract By studying a modified Friedmann equation which arises in an extension of general relativity which accommodates a time-dependent fundamental length L ( t ), we consider cosmological models where the scale factor diverges with an essential singularity at a finite future time. Such models have no dark energy in the conventional sense of energy possessing a simple pressure–energy relationship. Data on supernovae restrict the time from the present until the Rip to be longer than the current age of the Universe.
19015148
Correlated Isocurvature Fluctuation of Quintessence and Curvaton Scenario
We consider cosmic microwave background (CMB) anisotropy in models with quintessence taking into account of isocurvature fluctuation in the quintessence. It is shown that, if the primordial fluctuation of the quintessence has a correlation with the adiabatic density fluctuations, CMB angular power spectrum $C_l$ at low multipoles can be suppressed. Possible scenario of generating correlated mixture of the quintessence and adiabatic fluctuations is also discussed.
11074877
Constraining SuperWIMPy and Warm Subhalos with Future Submillilensing
Abstract We propose to observe QSO-galaxy strong lens systems to give a new constraint on the damping scale of the initial fluctuations. We find that the future observation of submilliarc scale astrometric shifts of the multiple lensed images of QSOs would find ∼ 10 ( 3 – 9 ) M ⊙ subhalos inside the macrolens halo. The superweakly interacting massive particles (superWIMPs) produced from a WIMP decay and the warm dark matter (WDM) particles that predict a comoving damping scale larger than ∼ 2 kpc can be constrained if ∼ 10 3 M ⊙ subhalos are detected.
119229900
Neutrino mass from cosmology: impact of high-accuracy measurement of the Hubble constant
Non-zero neutrino mass would affect the evolution of the Universe in observable ways, and a strong constraint on the mass can be achieved using combinations of cosmological data sets. We focus on the power spectrum of cosmic microwave background (CMB) anisotropies, the Hubble constant H0, and the length scale for baryon acoustic oscillations (BAO) to investigate the constraint on the neutrino mass, mν. We analyze data from multiple existing CMB studies (WMAP5, ACBAR, CBI, BOOMERANG, and QUAD), recent measurement of H0 (SHOES), with about two times lower uncertainty (5 %) than previous estimates, and recent treatments of BAO from the Sloan Digital Sky Survey (SDSS). We obtained an upper limit of mν < 0.2eV (95 % C.L.), for a flat ΛCDM model. This is a 40 % reduction in the limit derived from previous H0 estimates and one-third lower than can be achieved with extant CMB and BAO data. We also analyze the impact of smaller uncertainty on measurements of H0 as may be anticipated in the near term, in combination with CMB data from the Planck mission, and BAO data from the SDSS/BOSS program. We demonstrate the possibility of a 5σ detection for a fiducial neutrino mass of 0.1 eV or a 95 % upper limit of 0.04 eV for a fiducial of mν = 0 eV. These constraints are about 50 % better than those achieved without external constraint. We further investigate the impact on modeling where the dark-energy equation of state is constant but not necessarily -1, or where a non-flat universe is allowed. In these cases, the next-generation accuracies of Planck, BOSS, and 1 % measurement of H0 would all be required to obtain the limit mν < 0.05−0.06 eV (95 % C.L.) for the fiducial of mν = 0 eV. The independence of systematics argues for pursuit of both BAO and H0 measurements.
10883259
Duality of a supersymmetric model with the Pati-Salam group
Recently one of the authors proposed a dual theory of a Supersymmetric Standard Model (SSM), in which it is naturally understood that at least one quark (the top quark) should be heavy, i.e., almost the same order as the weak scale, and the supersymmetric Higgs mass parameter $\mu$ can naturally be expected to be small. However, the model cannot have Yukawa couplings of the lepton sector. In this paper, we examine a dual theory of a Supersymmetric Model with the Pati-Salam gauge group $SU(4)_{PS}\times SU(2)_L\times SU(2)_R $ with respect to the gauge group $SU(4)_{PS}$. In this scenario, Yukawa couplings of the lepton sector can be induced. In this model the Pati-Salam breaking scale should be around the SUSY breaking scale.
7954129
Exploring vacuum manifold of open string field theory
The global symmetry generated by Kn is a subgroup of the stringy gauge symmetry. We explore the part of the vacuum manifold related by this symmetry. Strong evidence is presented that the analytic classical solutions to the cubic string field theory found earlier in Refs. 5) [T. Takahashi and S. Tanimoto, J. High Energy Phys. 03 (2002), 033; hepth/0202133] and 6) [I. Kishimoto and T. Takahashi, Prog. Theor. Phys. 108 (2002), 591; hep-th/0205275] are actually related by the symmetry and, therefore, all of them describe the same tachyon vacuum. Some remaining subtlety is pointed out.
119263227
Tachyon vacuum of bosonic open string field theory in marginally deformed backgrounds
We consider bosonic open string field theory in marginally deformed backgrounds, which is obtained by expanding the string field around identity-based solutions associated with marginal deformations. We find a new set of string fields that satisfies the KB calgebra, but the nilpotent kinetic operator is that of the theory expanded around the identity-based marginal solution. By use of these string fields, we construct the tachyon vacuum solution in marginally deformed backgrounds. The vacuum energy density is equivalent to that of the tachyon vacuum without marginal deformations. The gauge invariant overlap is changed according to the effect of marginal deformations, as expected from known results in conformal field theory (CFT). These results suggest that the vacuum energy is zero for the identity-based marginal solutions in the original theory.
6660910
Hierarchical Mass Matrices in a Minimal SO(10) Grand Unification I
We continue to investigate the minimal SO(10) × U(1)H model which we proposed recently. Renormalization group analysis of the model results in natural predictions of quark-lepton masses and Kobayashi-Maskawa matrix along with neutrino mixings adequate for solar neutrino oscillation. e-mail address: mband@jpnyitp.bitnet Supported in part by Grant-in-Aid for Scientific Research from Ministry of Education, Science, and Culture (#06640416). JSPS Research Fellow. e-mail address: tomo@gauge.scphys.kyoto-u.ac.jp JSPS Research Fellow.
119293394
Observables for identity-based tachyon vacuum solutions
We consider a modified KBc algebra in bosonic open string field theory expanded around identity-based scalar solutions. By use of the algebra, classical solutions on the background are constructed and observables for them, including energy densities and gauge invariant overlaps, are calculable. These results are applied to evaluate observables analytically for both of the identity-based trivial pure gauge solution and the identity-based tachyon vacuum solution.