1,275 research outputs found

    Charged lepton and down-type quark masses in SU(1,1) model and the structure of higgs sector

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    The simplest noncompact group SU(1,1),when introduced as a symmetry group of the generations of quarks and leptons in the framework of a vector-like theory, gives an excellent viewpoint on low energy physics. The minimal setup of the scheme, however, gives phenomenologically unacceptable prediction on the Yukawa coupling matrices. This suggests the higgs sector has richer structure than we expect from the success of MSSM. The natural extension of the scheme, which has doubled structure in the higgs sector, is formulated. The framework admits this extension in a restrictive way. The possible patterns of Yukawa couplings are classified and the expressions of the coupling matrices are presented.Comment: 25 pages, no figure

    Strong CP Problem and the Natural Hierarchy of Yukawa Couplings

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    A possible solution to the strong CP problem is presented without using an axion. The model is based on the framework of the supersymmetric vectorlike theory with the spontaneous breakdown of the P-C-T-invariance. It is shown that the characteristic structure of the Yukawa coupling matrices that results from the spontaneous P-C-T-breaking plays the essential role in naturally realizing θ=0\theta=0 at the tree level. It is argued that θ=0\theta=0 will not be affected by the radiative corrections.Comment: 31 pages, no figure

    Physical Properties of UDF12 Galaxies in Cosmological simulations

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    We have performed a large cosmological hydrodynamics simulation tailored to the deep survey with the Hubble Space Telescope made in 2012, the so-called UDF12 campaign. After making a light-cone output, we have applied the same color selection criteria as the UDF12 campaign to select galaxies from our simulation, and then, have examined the physical properties of them as a proxy of the real observed UDF12 galaxies at z>7z > 7. As a result, we find that the halo mass is almost linearly proportional to the observed ultraviolet (UV) luminosity (4×1011 M⊙4 \times 10^{11}~{\rm M_{\odot}} at MUV=−21M_{\rm UV} = -21). The dust attenuation and UV slope β\beta well correlates with the observed UV luminosity, which is consistent with observations quantitatively. The star formation rate (SFR) is also linearly proportional to the stellar mass and the specific SFR shows only a weak dependency on the mass. We also find an increasing star formation history with a time-scale of ∼100\sim100 Myr in the high-zz galaxies. An average metallicity weighted by the Lyman continuum luminosity reaches up to >0.1>0.1 Solar even at z∼10z \sim 10, suggesting a rapid metal enrichment. We also expect ≥0.1\geq 0.1 mJy at 350 GHz of the dust thermal emission from the galaxies with H160≤27H_{160} \leq 27, which can be detectable with the Atacama Large Milimetre-submilimetre Array. The galaxies selected by the UDF12 survey contribute to only 52−−12%52--12\% of the cosmic SFR density from z∼7z \sim 7 to z∼10z \sim 10, respectively. The James Webb Space Telescope will push the detection fraction up to 77−−72%77--72\%.Comment: re-Submitted to MNRAS; 16 pages; 14 figures; 1 tables

    An Approach for School Counselors: Behavioral Consultation with Parents of Youth with School Attendance Problems

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    The current study investigates and discusses the effectiveness of behavioral consultations that school counselors can apply to students with school attendance problems (SAPs). A school counselor adopted the rapid school return approach in a school-based behavioral consultation with parents of a 13-year-old Japanese male student who refused to attend school. After the parents implemented the approach, the student resumed his regular school attendance, which continued until the end of junior high school. The A–B design in a single case study was employed as the research design. Throughout the implementation of the approach, the findings indicated that: (a) school counselors should conduct behavioral consultation sessions with parents periodically; (b) school counselors and parents should discuss who is responsible for the escorting process; (c) school staff and school counselors should collect accurate attendance data of students with SAPs daily until the end of the academic year; and (d) school counselors should view SAPs as a persistent problem for students, which can relapse at certain points during compulsory school. This current case study suggests that behavioral consultation with parents of youth with SAPs can be effective in dealing with students who refuse to attend school and are unwilling to seek specialists’ help
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