2,368 research outputs found

    Experimental Signature of Medium Modifications for rho and omega Mesons in the 12 GeV p + A Reactions

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    The invariant mass spectra of e+e- pairs produced in 12-GeV proton-induced nuclear reactions are measured at the KEK Proton-Synchrotron. On the low-mass side of the omega meson peak, a significant enhancement over the known hadronic sources has been observed. The mass spectra, including the excess, are well reproduced by a model that takes into account the density dependence of the vector meson mass modification, as theoretically predicted.Comment: 4 pages, 3 figures, Version accepted for Physical Review Lette

    Magic numbers in exotic nuclei and spin-isospin properties of {\it NN} interaction

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    The magic numbers in exotic nuclei are discussed, and their novel origin is shown to be the spin-isospin dependent part of the nucleon-nucleon interaction in nuclei. The importance and robustness of this mechanism is shown in terms of meson exchange, G-matrix and QCD theories. In neutron-rich exotic nuclei, magic numbers such as N = 8, 20, etc. can disappear, while N = 6, 16, etc. arise, affecting the structure of lightest exotic nuclei to nucleosynthesis of heavy elements.Comment: 4 pages, 3 figures, revte

    Standard Quantum Limits for broadband position measurement

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    I utilize the Caves-Milburn model for continuous position measurements to formulate a broadband version of the Standard Quantum Limit (SQL) for monitoring the position of a free mass, and illustrate the use of Kalman filtering to recover the SQL for estimating a weak classical force that acts on a quantum-mechanical test particle under continuous observation. These derivations are intended to clarify the interpretation of SQL's in the context of continuous quantum measurement.Comment: Replaced version: changed title, fixed algebra error at the very end, conclusions modified accordingly. Four pages, one eps figur

    Direct observation of photonic Landau levels and helical edge states in strained honeycomb lattices

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    We report the realization of a synthetic magnetic field for photons and polaritons in a honeycomb lattice of coupled semiconductor micropillars. A strong synthetic field is induced in both the s and p orbital bands by engineering a uniaxial hopping gradient in the lattice, giving rise to the formation of Landau levels at the Dirac points. We provide direct evidence of the sublattice symmetry breaking of the lowest-order Landau level wavefunction, a distinctive feature of synthetic magnetic fields. Our realization implements helical edge states in the gap between n=0 and n=1 Landau levels, experimentally demonstrating a novel way of engineering propagating edge states in photonic lattices. In light of recent advances in the enhancement of polariton-polariton nonlinearities, the Landau levels reported here are promising for the study of the interplay between pseudomagnetism and interactions in a photonic system

    Predictive use of the Maximum Entropy Production principle for Past and Present Climates

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    In this paper, we show how the MEP hypothesis may be used to build simple climate models without representing explicitly the energy transport by the atmosphere. The purpose is twofold. First, we assess the performance of the MEP hypothesis by comparing a simple model with minimal input data to a complex, state-of-the-art General Circulation Model. Next, we show how to improve the realism of MEP climate models by including climate feedbacks, focusing on the case of the water-vapour feedback. We also discuss the dependence of the entropy production rate and predicted surface temperature on the resolution of the model

    Adenoid cystic carcinoma of the peripheral lung: a case report

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    Adenoid cystic carcinoma of the peripheral lung is a rare entity. We recently encountered a patient with adenoid cystic carcinoma. A 75-year-old woman showed a nodular lesion with 10 mm in diameter in the right upper lung field on chest radiography. The diagnosis was unclear, but lung cancer could not be ruled out. Thoracoscopic biopsy was performed, and intraoperative pathological diagnosis revealed the carcinoma of the lung. We enforced upper lobectomy and mediastinal lymph node dissection to the patient. Histopathological examination revealed adenoid cystic carcinoma with a characteristic cribriform structure. Immunohistochemical examination revealed that the tumor cells were positive for thyroid transcription factor 1 (TTF-1), this tumor was diagnosed primary ACC of the lung

    Search for the Θ+\Theta^{+} pentaquark via the π−p→K−X\pi^-p\to K^-X reaction at 1.92 GeV/cc

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    The Θ+\Theta^+ pentaquark baryon was searched for via the π−p→K−X\pi^-p\to K^-X reaction in a missing-mass resolution of 1.4 MeV/c2c^2(FWHM) at J-PARC. π−\pi^- meson beams were incident on the liquid hydrogen target with the beam momentum of 1.92 GeV/cc. No peak structure corresponding to the Θ+\Theta^+ mass was observed. The upper limit of the production cross section averaged over the scattering angle of 2∘^{\circ} to 15∘^{\circ} in the laboratory frame was obtained to be 0.26 ÎŒ\mub/sr in the mass region of 1.51−-1.55 GeV/c2c^2.The upper limit of the Θ+\Theta^+ decay width using the effective Lagrangian approach was obtained to be 0.72 MeV/c2c^2 and 3.1 MeV/c2c^2 for JΘP=1/2+J^P_{\Theta}=1/2^+ and JΘP=1/2−J^P_{\Theta}=1/2^-, respectively.Comment: 5 pages, 3 figures, 1 tabl
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