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Toshinori Abe

Publications and source records attributed to Toshinori Abe.

9 recordsLinked to original sources

Parameterization of Gamma, e^+/- and Neutrino Spectra Produced by p-p Interaction in Astronomical Environment

We present the yield and spectra of stable secondary particles (gamma, e^+/-, nu_e, nubar_e, nu_mu, and nubar_mu) of p-p interaction in parameterized formulae to facilitate calculations involving them in astronomical environments. The formulae are derived on the up-to-date p-p interaction model by [Kamae05] which incorporates the logarithmically rising inelastic cross-section, the diffraction dissociation process, and the Feynman scaling violation. To improve fidelity to experimental data in lower energies, two baryon resonance contributions have been added: one representing Delta(1232) and the other multiple resonances around 1600MeV/c^2. The parametrized formulae predict that all secondary particle spectra be harder by about 0.05 in power-law indices than that of the incident proton and their inclusive cross-sections be larger than those predicted by p-p interaction models based on the Feynman scaling.

astro-ph↗

Optimizing the Linear Collider Detector for the Measurement of the Higgs to Charm Branching Ratio

Several different vertex detector designs for the Linear Collider Detector(LCD) are evaluated in the context of measurements of the branching ratio of the standard model Higgs particle decaying into charm/anti-charm final states. Fast Monte Carlo simulations are used to model the detector and neural network-optimized flavor tagging is used to perform the measurements. These tools are used to study the effects of pixel resolution, material thickness, and inner layer radius on the flavor tagging efficiency-purity curve and ultimately on the branching ratio measurement error.

hep-ex↗

The LCDROOT Analysis Package

The North American Linear Collider Detector group has developed simulation and analysis program packages. LCDROOT is one of the packages, and is based on ROOT and the C++ programing language to maximally benefit from object oriented programming techniques. LCDROOT is constantly improved and now has a new topological vertex finder, ZVTOP3. In this proceeding, the features of the LCDROOT simulation are briefly described.

hep-ex↗

The final SLD results for ALR and Alepton

We present the final measurements of the left-right cross-section asymmetry (ALR) for Z boson production by e+e- collisions and Z boson-lepton coupling asymmetry parameters Ae, Amu, and Atau in leptonic Z decays with the SLD detector at the SLAC Linear Collider. Using the complete sample of polarized Z bosons collected at SLD, we get ALR = 0.15056 +- 0.00239, Ae = 0.1544 +- 0.0060, Amu = 0.142 +- 0.015, and Atau = 0.136 +- 0.015. The ALR=Ae and Ae results are combined and we find Ae = 0.1516 +- 0.0021. Assuming lepton universality, we obtain a combined effective weak mixing angle of sin 2 theta eff W = 0.23098 +- 0.00026. Within the context of the SM, our result prefers a light Higgs mass.

hep-ex↗

A study of topological vertexing for heavy quark tagging

We compare heavy quark tagging and anti-tagging efficiencies for vertex detectors with different inner raddi using the topological vertex technique developed at the SLC/SLD experiment. Charm tagging benefits by going to very small inner radii.

hep-ex↗

LCD ROOT Simulation and Analysis Tools

The North American Linear Collider Detector group has developed a simulation program package based on the ROOT system. The package consists of Fast simulation, the reconstruction of the Full simulated data, and physics analysis utilities.

hep-ex↗

QCD with SLD

We present selected new results on strong interaction physics from the SLD experiment at the SLAC Linear Collider (SLC), symmetry tests of b\bar{b}g vertex, the rate of secondary b\bar{b} production via gluon splitting, the B hadron energy spectrum and rapidity correlations between identified charged hadrons. The parity violation in Z0 --> b\bar{b}g decays is consistent with electroweak theory plus QCD. New tests of T- and CP-conservation at the b\bar{b}g vertex are performed. A new measurement of the rate of gluon splitting into b\bar{b} pairs yields g_{b\bar{b}}=0.00307 +- 0.00071 (stat.) +- 0.00066 (syst.) (Preliminary). The B hadron energy spectrum is measured using a new inclusive technique, allowing tests of predictions for its shape and a measurement of < x_B > = 0.714 +- 0.005 (stat.) +- 0.007 (syst.) (Preliminary). A study of correlations in rapidity between pairs of identified pions, kaons and protons confirms that strangeness and baryon number areconserved locally, and shows local charge conservation between meson-baryon and strange-nonstrange pairs. Flavor-dependent long-range correlations are observed for all combinations of these hadron species. The first study of correlations using signed rapidities is done and find the first direct observation of baryon number ordering along the q\bar{q} axis.

hep-ex↗

Current Performance of the SLD VXD3

During 1996, the SLD collaboration completed construction and began operation of a new charge-coupled device (CCD) vertex detector (VXD3). Since then, its performance has been studied in detail and a new topological vertexing technique has been developed. In this paper, we discuss the design of VXD3, procedures for aligning it, and the tracking and vertexing improvements that have led to its world-record performance.

hep-ex↗

A preliminary measurement of the gluon splitting rate into $b\bar{b}$ pairs in hadronic $Z^0$ decays

We present a measurement of the rate of gluon splitting into bottom quarks, $g \to b\bar{b}$, in hadronic $Z^0$ decays collected by SLD from 1996 to 1998. The analysis was performed by looking for secondary bottom production in 4-jet events of any primary flavor. A topological vertex mass technique was used to tag the two jets with the smallest angle between them as $b/\bar{b}$. We obtained a rate of $g \to b\bar{b}$ per hadronic event to be $(3.07 \pm 0.71 {\rm (stat.)} \pm 0.66 {\rm (syst.)})\times 10^{-3}$ (preliminary).

hep-ex↗