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Nucleon excitations

Chinese Physics C 2010年第9期34卷 1241-1246页

作者： Eberhard Klempt helmholtz-institut für strahlen- und kernphysik der Universitt Bonn Nuβallee 14-16

The mass pattern of nucleon and Δ resonances is compared with predictions based on quark models,the Skyrme model,AdS/QCD,and the conjecture of chiral symmetry restoration.

关键词： baryon resonances AdS/QCD quark models chiral symmetry

Double heavy tri-hadron bound state via delocalized π bond

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Chinese Physics C 2019年第1期43卷 96-102页

作者： Li Ma Qian Wang Ulf-G. Meiβner helmholtz-institut für strahlen- und kernphysik and Bethe Center for Theoretical Physics Universit?t Bonn institut für kernphysik Institute for Advanced Simulation and Jülich Center for Hadron Physics Forschungszentrum

Abstract:The number of exotic candidates that are beyond the conventional quark model has increased dramatically over recent *** of these can be viewed as analogues of the ***,the existence of the triton indicates that bound states formed by three hadrons could also *** illustrate this possibility,we study the DD~*K and ■ systems using the Born-Oppenheimer *** leading order,only one-pion exchange potentials are *** means that the three constituents share one virtual *** is similar to the role of the delocalizedπbond for the formation of benzene in *** solving the Schr?dinger equation,we find two three-body DD~*K and ■bound states with masses4317.92_(-4.32)^(+3.66)Me V and 11013.65_(-8.84)^(+8.49)Me V,*** masses of their■and■ analogues are 4317.92~_(-6.55)(+6.13)Me V and 11013.65_(-9.02)^(+8.68)Me V,*** the experimental side,the ■bound state could be found by analyzing the current world data on the B→J/ψππKprocess,by focusing on the J/ψπK channel.

关键词： three-body system molecular state Schrdinger equation

The roper resonance in a finite volume

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Communications in Theoretical Physics 2020年第7期72卷 49-59页

作者： Daniel Severt Ulf-G Meiβner helmholtz-institut für strahlen-und kernphysik and Bethe Center for Theoretical Physics Universitat BonnD-53115 BonnGermany institute for Advanced Simulation Institut für Kernphysik and Jülich Center for Hadron PhysicsForschungszentrum JülichD-52425 JiilichGermany Tbilisi State University 0186 TbilisiGeorgia

We calculate the energy levels corresponding to the roper resonance based on a two-flavor chiral effective Lagrangian for pions,nucleons,deltas,and the roper resonance at the leading one-loop *** show that the roper m... 详细信息

关键词： Lattice QCD roper resonance finite volume methods

Accelerating ions with high-energy short laser pulses from submicrometer thick targets

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High Power Laser Science and Engineering 2016年第4期4卷 1-8页

作者： f.Wagner C.Brabetz O.Deppert M.roth T.Stohlker An.Tauschwitz A.Tebartz B.Zielbauer V.Bagnoud GSI helmholtzzentrum für Schwerionenforschung GmbH helmholtz institut Jena institut für kernphysik Technische Universitat Darmstadt institute for Theoretical Physics Frankfurt University

Using the example of the PHELIX high-energy short pulse laser we discuss the technical preconditions to investigate ion acceleration with submicrometer thick targets. We show how the temporal contrast of this system was improved to prevent pre-ionization of such targets on the nanosecond timescale. furthermore the influence of typical fluctuations or uncertainties of the on-target intensity on ion acceleration experiments is discussed. We report how these uncertainties were reduced by improving the assessment and control of the on-shot intensity and by optimizing the positioning of the target into the focal plane. finally we report on experimental results showing maximum proton energies in excess of 85 MeV for ion acceleration via the target normal sheath acceleration mechanism using target thicknesses on the order of one micrometer.

关键词： high-power laser technique laser-ion acceleration relativistic laser plasma interaction target normal sheath acceleration temporal contrast

Neutron-antineutron oscillations in the deuteron studied with NN and ■N interactions based on chiral effective field theory

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Chinese Physics C 2020年第3期44卷 28-32页

作者： Johann Haidenbauer Ulf-G.Meiβner institute for Advanced Simulation Institut für Kernphysik and Jülich Center for Hadron PhysicsForschungszentrum JülichD-52425 JülichGermany helmholtz-institut für strahlen-und kernphysik and Bethe Center for Theoretical Physics Universität Bonn53115 BonnGermany Tbilisi State University 0186 TbilisiGeorgia

Neutron-antineutron(n−n)oscillations in the deuteron are ***,the deuteron lifetime is calculated in terms of the free-space n−n oscillation time τn−n based on NN and NN interactions derived within chiral effective field theory(EfT).This results in(2.6±0.1)×10^22τ2^n−n s,which is close to the value obtained by Dover and collaborators more than three decades ago,but disagrees with recent EfT calculations that were performed within the perturbative scheme proposed by Kaplan,Savage,and *** reasons for the difference are discussed.

关键词： neutron-antineutron oscillations chiral effective field theory NN interaction antinucleon-nucleon interaction

Extracting the low-energy constant L_(0)^(r)at three flavors from pion-kaon scattering

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Communications in Theoretical Physics 2022年第6期74卷 61-65页

作者： Chaitra Kalmahalli Guruswamy Ulf-G Meißner Chien-Yeah Seng helmholtz-institut für strahlen-und kernphysik and Bethe Center for Theoretical Physics Universität BonnD-53115 BonnGermany institute for Advanced Simulation Institut für Kernphysik and Jülich Center for Hadron PhysicsForschungszentrum JülichD-52425 JülichGermany Tbilisi State University 0186 TbilisiGeorgia

based on our analysis of the contributions from the connected and disconnected contraction diagrams to the pion-kaon scattering amplitude,we provide the first determination of the only free low-energy constant at O(p^(4)),known as L_(0)^(r),in SU(4|1)Partially-Quenched Chiral Perturbation theory using the data from the Extended Twisted Mass collaboration,L_(0)^(r)(μ=M_(ρ))=0.77(20)(25)(7)(7)(2)·10^(-3).The theory uncertainties originate from the unphysical scattering length,the physical low-energy constants,the higher-order chiral corrections,the(lattice)meson masses and the pion decay constant,respectively.

关键词： lattice QCD partially quenched chiral perturbation theory pion-kaon scattering

Production Cross-Section Estimates for Strongly-Interacting Electroweak-Symmetry Breaking Sector resonances at Particle Colliders

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Communications in Theoretical Physics 2015年第12期64卷 701-709页

作者： Antonio Dobado GUO feng-Kun felipe J.Llanes-Estrada Departamento de física Teórica Universidad Complutense de Madrid State Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of Science helmholtz-institut für strahlen-und kernphysik and Bethe Center for Theoretical Physics Universitat Bonn

We are exploring a generic strongly-interacting Electroweak Symmetry Breaking Sector(EWSBS) with the low-energy effective field theory for the four experimentally known particles(W_L~±,Z_l,h) and its dispersion-relation based unitary *** this contribution we provide simple estimates for the production cross-section of pairs of the EWSBS bosons and their resonances at proton-proton colliders as well as in a future e^-e^+(or potentially aμ^-μ^+) collider with a typical few-TeV *** examine the simplest production mechanisms,tree-level production through a W(dominant when quantum numbers allow) and the simple effective boson approximation(in which the electroweak bosons are considered as collinear partons of the colliding fermions).We exemplify with custodial isovector and isotensor resonances at 2 TeV,the energy currently being discussed because of a slight excess in the ATLAS 2-jet *** find it hard,though not unthinkable,to ascribe this excess to one of these W_lW_l rescattering *** isovector resonance could be produced at a rate smaller than,but close to earlier CMS exclusion bounds,depending on the parameters of the effective *** ZZ excess is then problematic and requires additional physics(such as an additional scalar resonance).The isotensor one(that would describe all charge combinations) has smaller cross-section.

关键词： strongly interacting electroweak symmetry breaking

How does the S11 N^*(890) state emerge from a naive K-matrix fit?

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Communications in Theoretical Physics 2020年第10期72卷 92-97页

作者： Yao Ma Wen-Qi Niu Yu-fei Wang Han-Qing Zheng Department of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China helmholtz institut für strahlen-und kernphysik University of BonnBonn D-53115Germany Collaborative Innovation Center of Quantum Matter BeijingChina

We give a pedagogical analysis on K-matrix models describing theπN scattering amplitude,in S11 channel at low *** show how the correct use of analyticity in the s-channel and crossing symmetry in t-and u-channels leads to a much improved analytic behavior in the negative s region,in agreement with the prediction from chiral perturbation amplitudes in its validity *** analysis leads again to the conclusion that a genuine N^*(890)resonance exists.

关键词： pi N scattering subthreshold pole K-matrix N^*(890)

Towards the continuum coupling in nuclear lattice effective field theory Ⅰ: A three-particle model

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Chinese Physics C 2020年第12期44卷 177-183页

作者： J.-J.Wu Ulf-GMeißner School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China helmholtz-institut für strahlen-und kernphysik and Bethe Center for Theoretical Physics Universität BonnD-53115 BonnGermany institute for Advanced Simulation Institut für Kernphysikand Jülich Center for Hadron PhysicsForschungszentrum JülichD-52425 JülichGermany Tbilisi State University 0186 TbilisiGeorgia

Weakly bound states often occur in nuclear *** precisely understand their properties,the coupling to the continuum should be worked out *** the first step,we use a simple nuclear model in the continuum and on a lattice to investigate the influence of a third particle on a loosely bound state of a particle and a heavy *** approach is consistent with the Lüscher formalism.

关键词： nuclear lattice effective field theory continuum coupling Hamiltonian method