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Precise measurement of hadronic <i>τ</i>-decays with an <i>η</i> meson
Inami, K.,Ohshima, T.,Kaji, H.,Adachi, I.,Aihara, H.,Arinstein, K.,Aulchenko, V.,Aushev, T.,Bedny, I.,Bhardwaj, V.,Bondar, A.,Brač,ko, M.,Browder, T.E.,Chang, M.-C.,Chao, Y.,Chistov, R.,Cho, I.-S Elsevier 2009 Physics letters: B Vol.672 No.3
<P><B>Abstract</B></P><P>We have studied hadronic <I>τ</I> decay modes involving an <I>η</I> meson using 490 fb<SUP>−1</SUP> of data collected with the Belle detector at the KEKB asymmetric-energy <SUP>e+</SUP><SUP>e−</SUP> collider. The following branching fractions have been measured: B(<SUP>τ−</SUP>→<SUP>K−</SUP>η<SUB>ντ</SUB>)=(1.58±0.05±0.09)×<SUP>10−4</SUP>, B(<SUP>τ−</SUP>→<SUP>K−</SUP><SUP>π0</SUP>η<SUB>ντ</SUB>)=(4.6±1.1±0.4)×<SUP>10−5</SUP>, B(<SUP>τ−</SUP>→<SUP>π−</SUP><SUP>π0</SUP>η<SUB>ντ</SUB>)=(1.35±0.03±0.07)×<SUP>10−3</SUP>, B(<SUP>τ−</SUP>→<SUP>π−</SUP>KS0η<SUB>ντ</SUB>)=(4.4±0.7±0.2)×<SUP>10−5</SUP>, and B(<SUP>τ−</SUP>→<SUP>K∗−</SUP>η<SUB>ντ</SUB>)=(1.34±0.12±0.09)×<SUP>10−4</SUP>. These results are substantially more precise than previous measurements. The new measurements are compared with theoretical calculations based on the CVC hypothesis or the chiral perturbation theory. We also set upper limits on branching fractions for <I>τ</I> decays into <SUP>K−</SUP>KS0η<SUB>ντ</SUB>, <SUP>π−</SUP>KS0<SUP>π0</SUP>η<SUB>ντ</SUB>, <SUP>K−</SUP>ηη<SUB>ντ</SUB>, <SUP>π−</SUP>ηη<SUB>ντ</SUB> and non-resonant <SUP>K−</SUP><SUP>π0</SUP>η<SUB>ντ</SUB> final states.</P>
AKARI mid-infrared slitless spectroscopic survey of star-forming galaxies at <i>z</i> ≲ 0.5
Ohyama, Y.,Wada, T.,Matsuhara, H.,Takagi, T.,Malkan, M.,Goto, T.,Egami, E.,Lee, H.-M.,Im, M.,Kim, J.H.,Pearson, C.,Inami, H.,Oyabu, S.,Usui, F.,Burgarella, D.,Mazyed, F.,Imanishi, M.,Jeong, W.-S.,Miya EDP Sciences 2018 Astronomy and astrophysics Vol.618 No.-
<P><I>Context.</I> Deep mid-infrared (MIR) surveys have revealed numerous strongly star-forming galaxies at redshift <I>z</I> ≲ 2. Their MIR fluxes are produced by a combination of continuum and polycyclic aromatic hydrocarbon (PAH) emission features. The PAH features can dominate the total MIR flux, but are difficult to measure without spectroscopy.</P><P><I>Aims.</I> We aim to study star-forming galaxies by using a blind spectroscopic survey at MIR wavelengths to understand evolution of their star formation rate (SFR) and specific SFR (SFR per stellar mass) up to <I>z</I> ≃ 0.5, by paying particular attention to their PAH properties.</P><P><I>Methods.</I> We conducted a low-resolution (<I>R</I> ≃ 50) slitless spectroscopic survey at 5-13 <I>μ</I>m of 9 <I>μ</I>m flux-selected sources (>0.3 mJy) around the north ecliptic pole with the infrared camera (IRC) onboard AKARI. After removing 11 AGN candidates by using the IRC photometry, we identify 48 PAH galaxies with PAH 6.2, 7.7, and 8.6 <I>μ</I>m features at <I>z</I> < 0.5. The rest-frame optical-MIR spectral energy distributions (SEDs) based on CFHT and IRC imaging covering 0.37-18 <I>μ</I>m were produced, and analysed in conjunction with the PAH spectroscopy. We defined the PAH enhancement by using the luminosity ratio of the 7.7 <I>μ</I>m PAH feature over the 3.5 <I>μ</I>m stellar component of the SEDs.</P><P><I>Results.</I> The rest-frame SEDs of all PAH galaxies have a universal shape with stellar and 7.7 <I>μ</I>m bumps, except that the PAH enhancement significantly varies as a function of the PAH luminosities. We identify a PAH-enhanced population at <I>z</I> ≳ 0.35, whose SEDs and luminosities are typical of luminous infrared galaxies. They show particularly larger PAH enhancement at high luminosity, implying that they are vigorous star-forming galaxies with elevated specific SFR. Our composite starburst model that combines a very young and optically very thick starburst with a very old population can successfully reproduce most of their SED characteristics, although we cannot confirm this optically think component from our spectral analysis.</P>
Y. H. Matsuda,T. Nakamura,K. Kuga,S. Nakatsuji,S. Michimura,T. Inami,N. Kawamura,M. Mizumaki 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12
The valence state of Yb ions in β-YbAlB4 and its polymorph α-YbAlB4 has been investigated byusing X-ray absorption and emission spectroscopy in SPring-8 at temperatures from 2 to 280 K. Theobserved Yb valence is 2.78 ± 0.01 in β-YbAlB4 at 2 K by using the X-ray emission spectroscopy. The valence is found to gradually increase with increasing temperature toward the trivalent state,and the characteristic temperature of the valence fluctuation is expected to be about 290 K. Wealso found a small increase in the Yb valence ( 0.002) by applying a magnetic field of 32 T at40 K to β-YbAlB4.
The multiple merger assembly of a hyperluminous obscured quasar at redshift 4.6
Dí,az-Santos, T.,Assef, R. J.,Blain, A. W.,Aravena, M.,Stern, D.,Tsai, C.-W.,Eisenhardt, P.,Wu, J.,Jun, H. D.,Dibert, K.,Inami, H.,Lansbury, G.,Leclercq, F. American Association for the Advancement of Scienc 2018 Science Vol.362 No.6418
<P><B>Mergers drive a powerful dusty quasar</B></P><P>Massive galaxies in the early Universe host supermassive black holes at their centers. When material falls toward the black hole, it releases energy and is observed as a quasar. Astronomers found a population of powerful distant quasars that are obscured by dust, but it has been unclear how they are formed. Díaz-Santos <I>et al.</I> observed the dust-obscured quasar WISE J224607.56-052634.9 at submillimeter wavelengths, finding three small companion galaxies connected to the quasar by bridges of gas and dust. They inferred that galaxy mergers can provide both the raw material to power a quasar and large quantities of dust to obscure it.</P><P><I>Science</I>, this issue p. 1034</P><P>Galaxy mergers and gas accretion from the cosmic web drove the growth of galaxies and their central black holes at early epochs. We report spectroscopic imaging of a multiple merger event in the most luminous known galaxy, WISE J224607.56−052634.9 (W2246−0526), a dust-obscured quasar at redshift 4.6, 1.3 billion years after the Big Bang. Far-infrared dust continuum observations show three galaxy companions around W2246−0526 with disturbed morphologies, connected by streams of dust likely produced by the dynamical interaction. The detection of tidal dusty bridges shows that W2246−0526 is accreting its neighbors, suggesting that merger activity may be a dominant mechanism through which the most luminous galaxies simultaneously obscure and feed their central supermassive black holes.</P>
Hong, D.K.,Inami, T.,Yee, H.U. North-Holland Pub. Co 2007 Physics letters. Section B Vol.646 No.4
We construct a holographic model for baryons in the context of AdS/QCD and study the spin-12 nucleon spectra and its couplings to mesons, taking full account of the effects from the chiral symmetry breaking. A pair of 5D spinors is introduced to represent both left and right chiralities. Our model contains two adjustable parameters, the infrared cutoff and the Yukawa coupling of bulk spinors to bulk scalars, corresponding to the order parameter of chiral symmetry. Taking the lowest-lying nucleon mass as an input, we calculate the mass spectrum of excited nucleons and the nucleon couplings to pions. The excited nucleons show a parity-doubling pattern with smaller pion-nucleon couplings.
Belle Collaboration,Hayasaka, K.,Inami, K.,Miyazaki, Y.,Arinstein, K.,Aulchenko, V.,Aushev, T.,Bakich, A.M.,Bay, A.,Belous, K.,Bhardwaj, V.,Bischofberger, M.,Bozek, A.,Brako, M.,Browder, T.E.,Chang, M North-Holland Pub. Co 2010 Physics letters: B Vol.687 No.2
<P>We present a search for lepton-flavor-violating tau decays into three leptons (electrons or muons) using 782 fb(-1) of data collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. No evidence for these decays is observed and we set 90% confidence level upper limits on the branching fractions between 1.5 x 10(-8) and 2.7 x 10(-8). (C) 2010 Elsevier B.V. All rights reserved.</P>