Waseda University

About: Waseda University is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Catalysis & Large Hadron Collider. The organization has 24220 authors who have published 46859 publications receiving 837855 citations. The organization is also known as: Waseda daigaku & Sōdai.

Search for new phenomena in final states with large jet multiplicities and missing transverse momentum at √s = 8 TeV proton-proton collisions using the ATLAS experiment

Abstract: A search is presented for new particles decaying to large numbers (7 or more) of jets, with missing transverse momentum and no isolated electrons or muons. This analysis uses 20.3 fb−1 of pp collision data at s√=8 TeV collected by the ATLAS experiment at the Large Hadron Collider. The sensitivity of the search is enhanced by considering the number of b-tagged jets and the scalar sum of masses of large-radius jets in an event. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of various simplified supersymmetry-inspired models where gluinos are pair produced, as well as an mSUGRA/CMSSM model.

Measurement of the top quark forward-backward production asymmetry and its dependence on event kinematic properties

Abstract: We present new measurements of the inclusive forward-backward ttbar production asymmetry, AFB, and its dependence on several properties of the ttbar system. The measurements are performed with the full Tevatron data set recorded with the CDF II detector during ppbar collisions at sqrt(s) = 1.96 TeV, corresponding to an integrated luminosity of 9.4 fb^(-1). We measure the asymmetry using the rapidity difference Delta-y=y_(t)-y_(tbar). Parton-level results are derived, yielding an inclusive asymmetry of 0.164+/-0.047 (stat + syst). We observe a linear dependence of AFB on the top-quark pair mass M(ttbar) and the rapidity difference |Delta-y| at detector and parton levels. Assuming the standard model, the probabilities to observe the measured values or larger for the detector-level dependencies are 7.4*10^(-3) and 2.2*10^(-3) for M(ttbar) and |Delta-y| respectively. Lastly, we study the dependence of the asymmetry on the transverse momentum of the ttbar system at the detector level. These results are consistent with previous lower-precision measurements and provide additional quantification of the functional dependencies of the asymmetry.

Nernstian adsorbate-like bulk layer of organic radical polymers for high-density charge storage purposes

Abstract: Redox polymer layers with 2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl (TEMPO) groups showed nernstian adsorbate-like electrochemical behaviors up to submicrometer thicknesses, based on a fast charge propagation within the bulk layer and persistency in electrolyte solutions.

Fermi Large Area Telescope View of the Core of the Radio Galaxy Centaurus A

Abstract: We present gamma-ray observations with the LAT on board the Fermi Gamma-Ray Telescope of the nearby radio galaxy Centaurus~A. The previous EGRET detection is confirmed, and the localization is improved using data from the first 10 months of Fermi science operation. In previous work, we presented the detection of the lobes by the LAT; in this work, we concentrate on the gamma-ray core of Cen~A. Flux levels as seen by the LAT are not significantly different from that found by EGRET, nor is the extremely soft LAT spectrum ($\G=2.67\pm0.10_{stat}\pm0.08_{sys}$ where the photon flux is $\Phi\propto E^{-\G}$). The LAT core spectrum, extrapolated to higher energies, is marginally consistent with the non-simultaneous HESS spectrum of the source. The LAT observations are complemented by simultaneous observations from Suzaku, the Swift Burst Alert Telescope and X-ray Telescope, and radio observations with the Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry (TANAMI) program, along with a variety of non-simultaneous archival data from a variety of instruments and wavelengths to produce a spectral energy distribution (SED). We fit this broadband data set with a single-zone synchrotron/synchrotron self-Compton model, which describes the radio through GeV emission well, but fails to account for the non-simultaneous higher energy TeV emission observed by HESS from 2004-2008. The fit requires a low Doppler factor, in contrast to BL Lacs which generally require larger values to fit their broadband SEDs. This indicates the $\g$-ray emission originates from a slower region than that from BL Lacs, consistent with previous modeling results from Cen~A. This slower region could be a slower moving layer around a fast spine, or a slower region farther out from the black hole in a decelerating flow.

Average energy expended per ion pair in liquid argon

Abstract: The measurement of the $W$ value, the average energy expended per ion pair, in liquid argon for internal conversion electrons emitted from $^{207}\mathrm{Bi}$, is carried out by the electron-pulse method. Comparing with the $W$ value (26.09 eV) for $\ensuremath{\alpha}$ particles in a gas mixture of argon (95%) and methane (5%), the $W$ value in liquid argon is determined to be ${23.6}_{\ensuremath{-}0.3}^{+0.5}$ eV. This value is clearly smaller than that in gaseous argon (26.4 eV). Such a reduction of $W$ value in liquid argon can be explained by assuming the existence of the conduction band in liquid argon as in solid argon. Under this assumption, the $W$ value in liquid argon is estimated by applying the energy-balance method, which was used for the rare gases by Platzman. The calculated value thus obtained is in good agreement with the experimental result. Following the same method, the $W$ values for liquid krypton and liquid xenon are also estimated.