13,399 research outputs found

    Top-Quark Mass Measurement in the Dilepton Channel Using {\it in situ} Jet Energy Scale Calibration

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    We employ a top-quark mass measurement technique in the dilepton channel with {\it in situ} jet energy scale calibration. Three variables having different jet energy scale dependences are used simultaneously to extract not only the top-quark mass but also the energy scale of the jet from a single likelihood fit. Monte Carlo studies with events corresponding to an integrated luminosity of 5 fb−1^{-1} proton-proton collisions at the Large Hadron Collider s=7\sqrt{s} = 7 TeV are performed. Our analysis suggests that the overall jet energy scale uncertainty can be significantly reduced and the top-quark mass can be determined with a precision of less than 1 GeV/c2^2, including jet energy scale uncertainty, at the Large Hadron Collider.Comment: Submitted to Phys. Rev.

    Resonant Raman scattering of quantum wire in strong magnetic field

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    The resonant Raman scattering of a quantum wire in a strong magnetic field is studied, focused on the effect of long range Coulomb interaction and the spin-charge separation. The energy-momentum dispersions of charge and spin excitation obtained from Raman cross-section show the characteristc cross-over behaviour induced by inter-edge Coulomb interaction. The "SPE" peak near resonance in polarized spectra becomes broad due to the momentum dependence of charge velocity. The broad peak in the depolarized spectra is shown to originate from the disparity between charge and spin excitation velocity.Comment: RevTex file, 6 pages, no figure: To appear in Int. Jour. Mod. Phys.

    Two-pion-exchange parity-violating potential and n⃗p→dγ\vec{n} p \to d \gamma

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    We calculate the parity-violating nucleon-nucleon potential in heavy-baryon chiral perturbation theory up to the next-to-next-to-leading order. The one-pion exchange comes in the leading order and the next-to-next-to-leading order consists of two-pion-exchange and the two-nucleon contact terms. In order to investigate the effect of the higher order contributions, we calculate the parity-violating asymmetry in n⃗p→dγ\vec{n} p \to d \gamma at the threshold. The one-pion dominates the physical observable and the two-pion contribution is about or less than 10% of the one-pion contribution.Comment: 3 pages, contribution to the workshop PAVI06 held in Milos island, Greece, May 16-20, 200

    Parity Nonconservation in the Photodisintegration of the Deuteron at Low Energy

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    The parity-nonconserving asymmetry in the deuteron photodisintegration, γ⃗+d→n+p\vec{\gamma}+d\to n+p, is considered with the photon energy ranged up to 10 MeV above the threshold. The aim is to improve upon a schematic estimate assuming the absence of tensor as well as spin-orbit forces in the nucleon-nucleon interaction. The major contributions are due to the vector-meson exchanges, and the strong suppression of the pion-exchange contribution is confirmed. A simple argument, going beyond the observation of an algebraic cancellation, is presented. Contributions of meson-exchange currents are also considered, but found to be less significant.Comment: 12 pages, 6 figures, typeset by REVTeX (two-column format) and BIBTe

    Parity violation in pppp scattering and vector-meson weak-coupling constants

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    We calculate the parity-nonconserving longitudinal asymmetry in the elastic p⃗p\vec{p} p scattering at the energies where experimental data are available. In addition to the standard one-meson exchange weak potential, the variation of the strong-coupling constants and the non-standard effects such as form factors and 2π2 \pi-exchange description of the ρ\rho-exchange potential are taken into account. With the extra effects, we investigate the compatibility of the experimental data and the presently-known range of the vector-meson weak-coupling constants.Comment: Contribution to the proceedings of the 3rd Asia-Pacific conference on few-body problems in physics, Suranaree Univ. of Technology, Nakhon Ratchasima, Thailand, July 26 - 30, 200
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