Studies on optical properties of SnO-based glasses as lead-free glasses

The preparation of SnO-SiO(2), SnO-B(2)O(3), and SnO-GeO(2) glasses by melting in air was performed. The prepared SnO-GeO(2) glasses were large enough to measure optical properties whereas the vitrification in SnO-SiO(2) and SnO-B(2)O(3) systems was difficult. PbO-GeO(2) and BiO(1.5)-GeO(2) glasses were also prepared for comparison with SnO-GeO(2) glasses. The densities, glass transition temperatures, and optical properties such as refractive indices, dispersion, and transmission spectra of SnO-GeO(2), PbO-GeO(2), and BiO(1.5)-GeO(2) glasses were measured. On the basis of the results, the potential for SnO-GeO(2) glasses as lead-free glasses is particularly discussed from the viewpoint of optical properties

Long-term Change Trend of Climate at Aomori City

Characteristics of long-term change for air temperature, precipitation and snowfall-depth at Aomori city were analyzed with data during the 111 years, from 1886 to 1996. The typical results were as follows: (1) The increasing rate of the annual mean air temperature was 1.07℃/111 year. (2) The increasing rate of the monthly minimum air temperature was larger than that of the monthly maximum air temperature. (3) The increasing rate of the monthly air temperature was large from winter to spring, however, was not so from summer to autumn. (4) The decreasing rate of annual precipitation was 0.187 mm/year. (5) The 5-year moving average of annual snowfall-depth might indicate the existence of about 10-year period

Composite flavor-singlet scalar in twelve-flavor QCD

We report the calculation of the flavor-singlet scalar in the SU(3) gauge theory with the degenerate twelve fermions in the fundamental representation using a HISQ-type action at a fixed $\beta$. In order to reduce the large statistical error coming from the vacuum-subtracted disconnected correlator, we employ a noise reduction method and a large number of configurations. We observe that the flavor-singlet scalar is lighter than the pion in this theory from the calculations with the fermion bilinear and gluonic operators. This peculiar feature is considered to be due to the infrared conformality of this theory, and it is a promissing signal for a walking technicolor, where a light composite Higgs boson is expected to emerge by approximate conformal dynamics.Comment: 7 pages, 4 figures, Proceedings of the 31st International Symposium on Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, German

Flavor-singlet spectrum in multi-flavor QCD

Studying SU(3) gauge theories with increasing number of light fermions is relevant both for understanding the strong dynamics of QCD and for constructing strongly interacting extensions of the Standard Model (e.g. UV completions of composite Higgs models). In order to contrast these many-flavors strongly interacting theories with QCD, we study the flavor-singlet spectrum as an interesting probe. In fact, some composite Higgs models require the Higgs boson to be the lightest flavor-singlet scalar in the spectrum of a strongly interacting new sector with a well defined hierarchy with the rest of the states. Moreover, introducing many light flavors at fixed number of colors can influence the dynamics of the lightest flavor-singlet pseudoscalar. We present the on-going study of these flavor-singlet channels using multiple interpolating operators on high-statistics ensembles generated by the LatKMI collaboration and we compare results with available data obtained by the Lattice Strong Dynamics collaboration. For the theory with 8 flavors, the two collaborations have generated configurations that complement each others with the aim to tackle the massless limit using the largest possible volumes.Comment: contribution to the 35th International Symposium on Lattice Field Theory (Lattice 2017). Updated references and acknowledgment

Walking and conformal dynamics in many-flavor QCD

In the search for a realistic walking technicolor model, QCD with many flavors is an attractive candidate. From the series of studies by the LatKMI collaboration, we present updated results of the scaling properties of various hadron spectra, including the (pseudo)scalar, vector, and baryon channels, for $N_f=8$ QCD analyzed with the HISQ action. By comparing these with $N_f=12$ QCD, which has properties consistent with conformality, possible signals of walking dynamics are discussed. We also present a preliminary result of the flavor-singlet pseudoscalar mass in many-flavor QCD.Comment: 7 pages, 6 figures, Proceedings of the 33rd International Symposium on Lattice Field Theory (Lattice 2015), July 14-18, 2015, Kobe, Japa