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Charm mixing from BABAR

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Chinese Physics C 2008年第6期32卷 463-469页

作者： N.Neri BABAR Collaboration Universitàdi Pisa and INFNL.Bruno Pontecorvo 356127 PisaItaly

We present recent results from BABAR experiment for D^0-D^0mixing measurements. Mixing parameters can be measured in different ways using different D^ decay modes, here we discuss the most sensitive analyses such as D^0→ K^＋π^- where we had the first evidence of charm mixing, the measurement of the ratio of lifetimes of the decays D^0→ K^K^ and D^0→π^＋π^- relative to D^0→ K^-π^＋, the time dependent Dalitz plot analysis of D^0→K^＋π^-π^0. New limits on CP-violating time-integrated asymmetries in Do→ K^＋K^- and D^0→π^＋π^- are also discussed. The analyses presented are based on 384 fb^-1 data collected with the BABAR detector at the PEP-II asymmetric B Factory.

关键词： charm mixing flavor oscillations D^0 mesons BABAR

About Nature of Nuclear Forces

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Journal of Modern Physics 2015年第5期6卷 648-659页

作者： Boris V. Vasiliev pontecorvo street 17-408 Dubna Moscow District 141980 Russia

A new approach to the problem of nuclear force nature is considered. It is shown that an attraction in the proton-neutron pair can occur due to the exchange of relativistic electron. The estimation of this exchange energy is in agreement with the experimental values of the binding energy of some light nuclei. At that, neutron is regarded as a composite corpuscule consisting of proton and relativistic electron that allows predicting the neutron magnetic moment, its mass and the energy of its decay.

关键词： Proton Neutron Magnetic Moment Bohr Atom Relativistic Electron Deuteron

Nonlinear Effects for Bose Einstein Condensates in Optical Lattices

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量子光学学报 2006年第B8期12卷 59-60页

作者： Ennio Arimondo Dipartimento di Fisica E. Fermi Universitdt di Pisa Largo B. Pontecorvo 3 1-56127 Pisa Italy

Theory of light sail acceleration by intense lasers:an overview

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High Power Laser Science and Engineering 2014年第2期2卷 1-6页

作者： Andrea Macchi National Institute of Optics National Research Council (CNR/INO) Research Unit ‘Adriano Gozzini’Department of Physics ‘Enrico Fermi’ University of Pisa largo Bruno Pontecorvo 3 I-56127 Pisa Italy

A short overview of the theory of acceleration of thin foils driven by the radiation pressure of superintense lasers is presented. A simple criterion for radiation pressure dominance at intensities around 5×1020W cm-... 详细信息

关键词： light sail radiation pressure laser–plasma acceleration of electrons and ions laser-driven acceleration

Ritt's theorem and the Heins map in hyperbolic complex manifolds

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Science China Mathematics 2005年第Z1期48卷 238-243页

作者： Marco Abate Filippo Bracci Dipartimento di Matematica Università di Pisa Largo Pontecorvo 556127 PisaItalyDipartimento di Matematica Università di Roma "Tor Vergata"Via della Ricerca Scientifica00133 RomaItaly

Let X be a Kobayashi hyperbolic complex manifold, and assume that X does not contain compact complex submanifolds of positive dimension (e.g., X Stein). We shall prove the following generalization of Ritt's theorem: every holomorphic self-map f: X →X such that f(X) is relatively compact in X has a unique fixed point τ(f) ∈ X, which is attracting. Furthermore, we shall prove that τ(f) depends holomorphically on f in a suitable sense, generalizing results by Heins, Joseph-Kwack and the second author.

关键词： holomorphic self-map, fixed point, Wolff point, Ritt's theorem, Heins map, Stein manifold.

Spectral properties of Tm,Ho:LiYF_4 laser crystal

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Journal of Rare Earths 2011年第6期29卷 592-595页

作者：李春张莹张学建曾繁明 Mauro Tonelli 刘景和 School of Materials Science and Engineering Changchun University of Science and Technology Office of Foreign Affairs Jilin Architectural and Civil Engineering Institute NEST-CNR and Dipartimento di Fisica Universita` di Pisa Largo B. Pontecorvo 3 56127 Pisa Italy

The LiYF4 single crystal codoped with thulium and holmium ions was successfully grown by the Cz method. The optimal technical parameters obtained were as follows： the pulling rate was 0.16 mm/h; the rotation speed was 3 rpm; the cooling rate was 15 °C/h. The result of XRD curve showed that as-grown Tm,Ho：LiYF4 laser crystal belonged to the monoclinic system with scheelite-type structure and space group I41/a. The cell parameters calculated were： a=0.52160 nm, c=1.09841 nm and Z=4. Absorption and fluorescence spectra of Tm,Ho：LiYF4 laser crystal at room temperature were measured and analysed. The absorption cross section, FWHM and absorption coefficient at 779.3 nm calculated were 7.44×10–21 cm2, 8.7 nm and 2.23 cm–1, respectively. An intensive fluorescence emission peak appeared near 2045 nm. The emission cross section and fluorescence lifetime were 0.87×10–20 cm2 and 10.8 ms, respectively. The ratio of Tm–Ho transfer to its back-transfer process was 10.6.

关键词： Tm Ho:LiYF4 laser crystal Cz method absorption spectrum fluorescence spectrum rare earths

Quantal symmetries in the non-linear σ model with Maxwell and non-Abelian Chern-Simons terms

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Chinese Physics C 2010年第5期34卷 535-538页

作者：王珂姜云国霍秋红 Department of Applied Physics Beijing University of Technology Department of Physics University of Pisa INFN Sezione di PisaLargo Pontecorvo3.Ed.C56127 PisaItaly College of Materials Science and Engineering Beijing University of Technology

The quantal symmetry property of the CP1 nonlinear σ model with Maxwell non-Abelian ChernSimons terms in(2+1) dimension is *** the Coulomb gauge,the system is quantized by using the Faddeev-Senjanovic(FS) path-integral *** on the quantaum Noether theorem,the quantal conserved angular momentum is derived and the fractional spin at the quantum level in this system is presented.

关键词： non-linear sigma model non-Abelian Chern-Simons fractional spin

Numerical simulation of time delay interferometry for TAIJI and new LISA

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Research in Astronomy and Astrophysics 2019年第4期19卷 95-108页

作者： Gang Wang Wei-Tou Ni INFN Gran Sasso Science Institute INFN Sezione di PisaEdificio CLargo Bruno Pontecorvo National Astronomical Observatories Chinese Academy of Sciences State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsChinese Academy of Sciences

The success of LISA Pathfinder in demonstrating the LISA drag-free requirement paved the way for using space interferometers to detect low-frequency and middle-frequency gravitational waves(GWs). The TAIJI GW mission and the new LISA GW mission propose using an arm length of 3 Gm(1 Gm = 10~6 km) and an arm length of 2.5 Gm respectively. For a space laser-interferometric GW antenna,due to astrodynamical orbit variation, time delay interferometry(TDI) is needed to achieve nearly equivalent equal-arms for suppressing the laser frequency noise below the level of optical path noise, acceleration noise, etc in order to attain the requisite sensitivity. In this paper, we simulate TDI numerically for the TAIJI mission and the new LISA mission. To do this, we work out a set of 2200-day(6-year) optimized science orbits for each mission starting on 2028 March 22 using the CGC 2.7.1 ephemeris framework. Then we use the numerical method to calculate the residual optical path differences of the first-generation TDI configurations and the selected second-generation TDI configurations. The resulting optical path differences of the second-generation TDI configurations calculated for TAIJI, new LISA and eLISA are well below their respective requirements for laser frequency noise cancelation. However, for the first-generation TDI configurations, the original requirements need to be relaxed by 3 to 30 fold to be satisfied. For TAIJI and the new LISA, about one order of magnitude relaxation would be good and recommended; this could be borne on the laser stability requirement in view of recent progress in laser stability, or the GW detection sensitivities of the second-generation TDIs have to be used in the diagnosis of the observed data instead of the commonly used X, Y and Z TDIs.

关键词： gravitational waves methods:numerical techniques:interferometric

Broadband Vibrational Cooling of Cold Cesium Molecules： Theory and Experiments

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Chinese Journal of Chemical Physics 2009年第2期22卷 149-156页

作者： D. Sofikitis A. Fioretti S. Weber M. Viteau A. Chotia R. Horchani M. Allegrini B. Chatel D. Comparat P. Pillet Laboratoire Aimé Cotton CNRS Université Paris-Sud Bat. 505 91405 Orsay France Laboratoire Collisions Agrégats Réactivité (UMR 5589 CNRS-Université Paul Sabatier Toulouse 3) IRSAMC Toulouse France CNISM Dipartimento di Fisica Universita di Pisa Largo Pontecorvo 356127 PISA Italy

The use of a broadband, frequency shaped femtosecond laser on translationally cold cesium molecules has recently demonstrated to be a very efficient method of cooling also the vibrational degree of freedom. A sample of cold molecules, initially distributed over several vibrational levels, has thus been transfered into a single selected vibrational level of the singlet X^1∑g ground electronic state. Our method is based on repeated optical pumping by laser light with a spectrum broad enough to excite all populated vibrational levels but limited in its frequency bandwidth with a spatial light modulator. In such a way we are able to eliminate transitions from the selected level, in which molecules accumulate. In this paper we briefly report the main experimental results and then address, in a detailed way by computer simulations, the perspectives for a ＂complete＂ cooling of the molecules, including also the rotational degree of freedom. Since the pumping process strongly depends on the relative shape of the ground and excited potential curves, ro-vibrational cooling through different excited states is theoretically compared.

关键词： Cold molecule Optical pumping Pulse .shaping Ultrashort pulse Laser cooling