Higgs Boson Mass Bounds in the Standard and Minimal Supersymmetric Standard Model with Four Generations

We study the question of distinguishability of the Higgs sector between the standard model with four generations(SM4) and the minimal supersymmetric standard model with four generations (MSSM4). We find that a gap exists between the SM4 and MSSM4 Higgs boson masses for a range of the fourth generation fermion mass considered in the analysis at a fixed top quark mass. We also compare the Higgs boson mass bounds in these models with those in the standard and the minimal supersymmetric standard models.Comment: 11 pages, Revtex, 3 postscript figures, accepted for publication in Mod. Phys. Lett.

Half-Skyrmions and the Equation of State for Compact-Star Matter

The half-skyrmions that appear in dense baryonic matter when skyrmions are put on crystals modify drastically hadron properties in dense medium and affect strongly the nuclear tensor forces, thereby influencing the equation of state (EoS) of dense nuclear and asymmetric nuclear matter. The matter comprised of half skyrmions has vanishing quark condensate but non-vanishing pion decay constant and could be interpreted as a hadronic dual of strong-coupled quark matter. We infer from this observation combined with certain predictions of hidden local symmetry in low-energy hadronic interactionsa a set of new scaling laws -- called "new-BR" -- for the parameters in nuclear effective field theory controlled by renormalization-group flow. They are subjected to the EoS of symmetric and asymmetric nuclear matter, and are then applied to nuclear symmetry energies and properties of compact stars. The changeover from the skyrmion matter to a half-skyrmion matter that takes place after the cross-over density $n_{1/2}$ provides a simple and natural field theoretic explanation for the change of the EoS from soft to stiff at a density above that of nuclear matter required for compact stars as massive as $\sim 2.4M_\odot$. Cross-over density in the range 1.5n_0 \lsim n_{1/2} \lsim 2.0 n_0 has been employed, and the possible skyrmion half-skyrmion coexistence {or cross-over} near $n_{1/2}$ is discussed. The novel structure of {the tensor forces and} the EoS obtained with the new-BR scaling is relevant for neutron-rich nuclei and compact star matter and could be studied in RIB (rare isotope beam) machines.Comment: 12 pages, 7 figures, slightly revised for PRC, in pres

Threshold corrections to the radiative breaking of electroweak symmetry and neutralino dark matter in supersymmetric seesaw model

We study the radiative electroweak symmetry breaking and the relic abundance of neutralino dark matter in the supersymmetric type I seesaw model. In this model, there exist threshold corrections to Higgs bilinear terms coming from heavy singlet sneutrino loops, which make the soft supersymmetry breaking (SSB) mass for up-type Higgs shift at the seesaw scale and thus a minimization condition for the Higgs potential is affected. We show that the required fine-tuning between the Higgsino mass parameter mu and the SSB mass for up-type Higgs may be reduced at the electroweak scale, due to the threshold corrections. We also present how the parameter mu depends on the SSB B-parameter for heavy singlet sneutrinos. Since the property of neutralino dark matter is quite sensitive to the size of mu, we discuss how the relic abundance of neutralino dark matter is affected by the SSB B-parameter. Taking the SSB B-parameter of order of a few hundreds TeV, the required relic abundance of neutralino dark matter can be correctly achieved. In this case, dark matter is a mixture of bino and Higgsino, under the condition that gaugino masses are universal at the grand unification scale.Comment: 27 pages, 3 figures; references added, discussion about RGEs added, the version published on PR

Possible Deviation from the Tri-bimaximal Neutrino Mixing in a Seesaw Model

We propose a simple but suggestive seesaw model with two phenomenological conjectures: three heavy (right-handed) Majorana neutrinos are degenerate in mass in the symmetry limit and three light Majorana neutrinos have the tri-bimaximal mixing pattern $V^{}_0$. We show that a small mass splitting between the first generation and the other two generations of heavy Majorana neutrinos is responsible for the deviation of the solar neutrino mixing angle $\theta^{}_{12}$ from its initial value $35.3^\circ$ given by $V^{}_0$, and the slight breaking of the mass degeneracy between the second and third generations of heavy Majorana neutrinos results in a small mixing angle $\theta^{}_{13}$ and a tiny departure of the atmospheric neutrino mixing angle $\theta^{}_{23}$ from $45^\circ$. It turns out that a normal hierarchy of the light neutrino mass spectrum is favored in this seesaw scenario.Comment: RevTex 12 pages (2 EPS figures included). More discussions and references adde

The Wave Function and the Minimum Uncertainty Function of the Time Dependent Harmonic Oscillator(New Developments in Statistical Physics Similarities in Diversities,YITP Workshop)

この論文は国立情報学研究所の電子図書館事業により電子化されました。The time dependent harmonic oscillator is solved explicitly for quantum mechanics by the operator method with an auxiliary condition as the classical solution. Two classical invariant quantities which determine whether or not the system is bound are derived by the classical equation of motion. We obtain the invariant operator from one classical invariant quantity. Its eigenfunction is related to the solution of Schrodinger equation of the system and its eigenvalue is related to another classical quantity. The wave function is evaluated exactly by the eigenfunction of the invariant operator but it is not the eigenfunction of the Hamiltonian of the system. The uncertainty which calculates with the wave function is not a minimum one. We will confirm that the function which holds minimum uncertainty is a eigenfunction of the Hamiltonian

Gravitational Lensing by Power-Law Mass Distributions: A Fast and Exact Series Approach

We present an analytical formulation of gravitational lensing using familiar triaxial power-law mass distributions, where the 3-dimensional mass density is given by $\rho(X,Y,Z) = \rho_0 [1 + (\frac{X}{a})^2 + (\frac{Y}{b})^2 + (\frac{Z}{c})^2]^{-\nu/2}$. The deflection angle and magnification factor are obtained analytically as Fourier series. We give the exact expressions for the deflection angle and magnification factor. The formulae for the deflection angle and magnification factor given in this paper will be useful for numerical studies of observed lens systems. An application of our results to the Einstein Cross can be found in Chae, Turnshek, & Khersonsky (1998). Our series approach can be viewed as a user-friendly and efficient method to calculate lensing properties that is better than the more conventional approaches, e.g., numerical integrations, multipole expansions.Comment: 24 pages, 3 Postscript figures, ApJ in press (October 10th

Measurement of Source Star Colors with the K2C9-CFHT Multi-color Microlensing Survey

K2 Campaign 9 (K2C9) was the first space-based microlensing parallax survey capable of measuring microlensing parallaxes of free-floating planet candidate microlensing events. Simultaneous to K2C9 observations we conducted the K2C9 Canada-France-Hawaii Telescope Multi-Color Microlensing Survey (K2C9-CFHT MCMS) in order to measure the colors of microlensing source stars to improve the accuracy of K2C9's parallax measurements. We describe the difference imaging photometry analysis of the K2C9-CFHT MCMS observations, and present the project's first data release. This includes instrumental difference flux lightcurves of 217 microlensing events identified by other microlensing surveys, reference image photometry calibrated to PanSTARRS data release 1 photometry, and tools to convert between instrumental and calibrated flux scales. We derive accurate analytic transformations between the PanSTARRS bandpasses and the Kepler bandpass, as well as angular diameter-color relations in the PanSTARRS bandpasses. To demonstrate the use of our data set, we analyze ground-based and K2 data of a short timescale microlensing event, OGLE-2016-BLG-0795. We find the event has a timescale $t_{\rm E}=4.5 \pm 0.1$~days and microlens parallax $\pi_{\rm E}=0.12 \pm 0.03$ or $0.97 \pm 0.04$, subject to the standard satellite parallax degeneracy. We argue that the smaller value of the parallax is more likely, which implies that the lens is likely a stellar-mass object in the Galactic bulge as opposed to a super-Jupiter mass object in the Galactic disk.Comment: Submitted to PAS