ITP OpenIR研究单元&专题: 理论物理所2015年知识产出
http://ir.itp.ac.cn/:80/handle/311006/20730
Sat, 17 Nov 2018 16:58:22 GMT2018-11-17T16:58:22ZAnthropic considerations in nuclear physics
http://ir.itp.ac.cn/:80/handle/311006/21132
题名: Anthropic considerations in nuclear physics
作者: Meissner, UG; Meissner, UG (reprint author), Univ Bonn, Helmholtz Inst Strahlen & Kernphys Theorie, D-53155 Bonn, Germany.
摘要: In this short review, I discuss the sensitivity of the generation of the light and the life-relevant elements such as carbon and oxygen under changes of the parameters of the Standard Model pertinent to nuclear physics. Chiral effective field theory allows for a systematic and precise description of the forces between two, three and four nucleons. In this framework, variations under the light quark masses and the electromagnetic fine-structure constant can also be consistently calculated. Combining chiral nuclear effective field theory with Monte Carlo simulations allows to further calculate the properties of nuclei, in particular of the Hoyle state in carbon, that plays a crucial role in the generation of the life-relevant elements in hot, old stars. The dependence of the triple-alpha process on the fundamental constants of nature is calculated, and some implications for our anthropic view of the Universe are discussed.Mon, 21 Nov 2016 07:25:36 GMThttp://ir.itp.ac.cn/:80/handle/311006/211322016-11-21T07:25:36ZEffect of tensor force on the density dependence of symmetry energy within the BHF framework
http://ir.itp.ac.cn/:80/handle/311006/21131
题名: Effect of tensor force on the density dependence of symmetry energy within the BHF framework
作者: Pei, W; Wei, Z; Pei, W (reprint author), Chinese Acad Sci, Inst Modern Phys, Lanzhou 730000, Peoples R China.
摘要: The effect of tensor force on the density dependence of nuclear symmetry energy has been investigated within the framework of the Brueckner-Hartree-Fock (BHF) approach. It is shown that the tensor force manifests its effect via the tensor (SD1)-S-3 channel. The density dependence of symmetry energy E-sym turns out to be determined essentially by the tensor force from the pi meson and rho meson exchanges via the (SD1)-S-3 coupled channel. Increasing the strength of the tensor component due to the rho-meson exchange tends to enhance the repulsion of the equation of state of symmetric nuclear matter and leads to the reduction of symmetry energy. The present results confirm the dominant role played by the tensor force in determining nuclear symmetry energy and its density dependence within the microscopic BHF framework.Mon, 21 Nov 2016 07:25:35 GMThttp://ir.itp.ac.cn/:80/handle/311006/211312016-11-21T07:25:35ZOne right-handed neutrino to generate complete neutrino mass spectrum in the framework of NMSSM
http://ir.itp.ac.cn/:80/handle/311006/21129
题名: One right-handed neutrino to generate complete neutrino mass spectrum in the framework of NMSSM
作者: Tang, YL; Tang, YL (reprint author), Chinese Acad Sci, Inst Theoret Phys, POB 2735, Beijing 100190, Peoples R China.
摘要: The see-saw mechanism is usually applied to explain the lightness of neutrinos. The traditional see-saw mechanism introduces at least two right-handed neutrinos for the realistic neutrino spectrum. In the case of supersytnmetry, loop corrections can also contribute to neutrino masses, which lead to the possibility to generate the neutrino spectrum by introducing just one right-handed neutrino. To be realistic, MSSM suffers from the g problem and other phenomenological difficulties, so we extend NMSSM (the MSSM with a singlet S) by introducing one single right-handed neutrino superfield (N) and relevant phenomenology is discussed. (C) 2014 The Author. Published by Elsevier B.V.Mon, 21 Nov 2016 07:25:34 GMThttp://ir.itp.ac.cn/:80/handle/311006/211292016-11-21T07:25:34ZThe evaporation residue in the fission state of barium nuclei within relativistic mean-field theory
http://ir.itp.ac.cn/:80/handle/311006/21130
题名: The evaporation residue in the fission state of barium nuclei within relativistic mean-field theory
作者: Bhuyan, M; Patra, SK; Gupta, RK; Bhuyan, M (reprint author), Chinese Acad Sci, Inst Theoret Phys, Beijing 100190, Peoples R China.
摘要: The evaporation residue of barium isotopes is investigated in a microscopic study using relativistic mean field theory. The investigation includes the isotopes of barium from the valley of stability to the exotic proton-rich region. The ground as well as neck configurations for these nuclei are generated from their total nucleonic density distributions of the corresponding state. We have estimated the constituents (number of nucleons) in the elongated neck region of the fission state. We found the a-particle as the constituent of the neck of Ba-isotopes, referred to as the evaporated residue in heavy-ion reaction studies. A strong correlation between the neutron and proton is observed throughout the isotopic chain.Mon, 21 Nov 2016 07:25:34 GMThttp://ir.itp.ac.cn/:80/handle/311006/211302016-11-21T07:25:34ZMinimal Length Effects on Tunnelling from Spherically Symmetric Black Holes
http://ir.itp.ac.cn/:80/handle/311006/21128
题名: Minimal Length Effects on Tunnelling from Spherically Symmetric Black Holes
作者: Mu, BR; Wang, P; Yang, HT; Mu, BR (reprint author), Univ Elect Sci & Technol China, Sch Phys Elect, Chengdu 610054, Peoples R China.
摘要: We investigate effects of the minimal length on quantum tunnelling from spherically symmetric black holes using the Hamilton-Jacobi method incorporating the minimal length. We first derive the deformed Hamilton-Jacobi equations for scalars and fermions, both of which have the same expressions. The minimal length correction to the Hawking temperature is found to depend on the black hole's mass and the mass and angular momentum of emitted particles. Finally, we calculate a Schwarzschild black hole's luminosity and find the black hole evaporates to zero mass in infinite time.Mon, 21 Nov 2016 07:25:33 GMThttp://ir.itp.ac.cn/:80/handle/311006/211282016-11-21T07:25:33ZDiscrete Boltzmann modeling of multiphase flows: hydrodynamic and thermodynamic non-equilibrium effects
http://ir.itp.ac.cn/:80/handle/311006/21127
题名: Discrete Boltzmann modeling of multiphase flows: hydrodynamic and thermodynamic non-equilibrium effects
作者: Gan, YB; Xu, AG; Zhang, GC; Succi, S; Xu, AG (reprint author), Inst Appl Phys & Computat Math, Natl Key Lab Computat Phys, POB 8009-26, Beijing, Peoples R China.
摘要: A discrete Boltzmann model (DBM) is developed to investigate the hydrodynamic and thermodynamic non-equilibrium (TNE) effects in phase separation processes. The interparticle force drives changes and the gradient force, induced by gradients of macroscopic quantities, opposes them. In this paper, we investigate the interplay between them by providing a detailed inspection of various non-equilibrium observables. Based on the TNE features, we define TNE strength which roughly estimates the deviation amplitude from the thermodynamic equilibrium. The time evolution of the TNE intensity provides a convenient and efficient physical criterion to discriminate the stages of the spinodal decomposition and domain growth. Via the DBM simulation and this criterion, we quantitatively study the effects of latent heat and surface tension on phase separation. It is found that the TNE strength attains its maximum at the end of the spinodal decomposition stage, and it decreases when the latent heat increases from zero. The surface tension effects are threefold, prolong the duration of the spinodal decomposition stage, decrease the maximum TNE intensity, and accelerate the speed of the domain growth stage.Mon, 21 Nov 2016 07:25:32 GMThttp://ir.itp.ac.cn/:80/handle/311006/211272016-11-21T07:25:32ZMOLECULAR STRUCTURES IN LIGHT ATOMIC NUCLEI
http://ir.itp.ac.cn/:80/handle/311006/21126
题名: MOLECULAR STRUCTURES IN LIGHT ATOMIC NUCLEI
作者: Xu, FR; Wang, SM; Pei, JC; Chen, WJ; Xu, ZX; Xu, FR (reprint author), Peking Univ, Sch Phys, State Key Lab Nucl Phys & Technol, Beijing 100871, Peoples R China.
摘要: We have established the anti-symmetrized molecular dynamics (AMD) calculation including a computational code. A phenomenological Gogny-type nuclear force including spin-orbit coupling has been used. A zero-range three-body force described by 8 function is adopted. In order to reduce the computing time, in the present work we mainly performed variation-before-projection calculations. Again due to the limitation of computer capability, the calculations are limited to light nuclei. In the present work, we have investigated the light nuclei from the lightest He-3 to heaviest C-16 nuclei. From calculated density distributions by the AMD model, we can see clustering or molecular structures in the light nuclei. The AMD model can also give reasonable binding energies compared with data. We have calculated the spectra of the investigated nuclei, obtaining quite good results compared with experimental data. As a example, we performed a variation-after-projection calculation for Be-10, showing the significant improvement in the calculation of binding energy. The calculations give that the 0(+) and 1(-) states have different molecular structures.Mon, 21 Nov 2016 07:25:31 GMThttp://ir.itp.ac.cn/:80/handle/311006/211262016-11-21T07:25:31ZHALF-LIVES OF THIRTEEN DOUBLE beta(-)-DECAY CANDIDATES WITH TWO NEUTRINOS
http://ir.itp.ac.cn/:80/handle/311006/21125
题名: HALF-LIVES OF THIRTEEN DOUBLE beta(-)-DECAY CANDIDATES WITH TWO NEUTRINOS
作者: Ren, YJ; Ren, ZZ; Ren, YJ (reprint author), Nanjing Univ, Dept Phys, Nanjing 210093, Jiangsu, Peoples R China.
摘要: Double beta(-)-decay with two neutrinos is one of the important decay modes for an unstable nucleus which can spontaneously change into a stable nucleus. It is also a very complex decay process where three kinds of interactions, the strong interaction, the Coulomb interaction, and the weak interaction, are involved. Recently we have made a systematic analysis on the experimental data of nuclear double beta(-)-decay and proposed that there is a law between the logarithm of double beta(-)-decay half-lives and the reciprocal of the decay energy. This is a simple and accurate law for half-lives of the double beta(-)-decay. We use this law to predict the half-lives of the double beta(-)-decay candidates where the mass number of parent nuclei ranges from A=70 (Zn-70) to A = 204 (Hg-204). Numerical results of the half-lives show that Ce-142 is a very interesting candidate for future experiments to search new emitters of the double beta(-)-decay. We also compare the half-lives of double beta(-)-decay and alpha-decay for Ce-142 where its decay energies of two modes are close and find that double beta(-)-decay dominates in this case although double beta(-)-decay is a second order process of the weak interaction. The branching ratios between double beta(-)-decay and alpha-decay are listed for the candidates of double beta(-)-decay.Mon, 21 Nov 2016 07:25:30 GMThttp://ir.itp.ac.cn/:80/handle/311006/211252016-11-21T07:25:30ZThe phase diagram and radial collapse of an inflated soft tube under twist
http://ir.itp.ac.cn/:80/handle/311006/21124
题名: The phase diagram and radial collapse of an inflated soft tube under twist
作者: Meng, F; Chen, JZY; Doi, M; Ouyang, ZC; Chen, JZY (reprint author), Univ Waterloo, Dept Phys & Astron, Waterloo, ON N2L 3G1, Canada.
摘要: When an inflated soft tube such as a cylindrical balloon is twisted, mechanical instability can arise and produces a kink-like radius collapsing in the middle of the tube. Here this phenomenon inspires us to theoretically analyze a standard non-linear model of rubber elasticity for soft tubes. We show that there exists a critical pressure beyond which such instability arises. The critical pressure depends on the elastic properties of the tube material and the geometric dimensions of the thin-walled tube. This general theory covers a large class of soft materials and explains why twist-induced collapsing is observable in soft and thin elastic tubes such as balloons, but not in hard and thick tubes such as water hoses.Mon, 21 Nov 2016 07:25:29 GMThttp://ir.itp.ac.cn/:80/handle/311006/211242016-11-21T07:25:29ZStudy of Nonleptonic B-q(*) -> DqV and PqD* Weak Decays
http://ir.itp.ac.cn/:80/handle/311006/21123
题名: Study of Nonleptonic B-q(*) -> DqV and PqD* Weak Decays
作者: Chang, Q; Hu, XH; Sun, JF; Wang, XL; Yang, YL; Sun, JF (reprint author), Henan Normal Univ, Inst Particle & Nucl Phys, Xinxiang 453007, Peoples R China.
摘要: Motivated by the powerful capability of measurement for the b hadron decays at LHC and SuperKEKB/Belle-II, the nonleptonic (B) over bar* -> D (D) over bar*, Dp(-), DK*(-), pi D*, KD* decays are studied. With the amplitudes calculated with factorization approach and the form factors evaluated with the BSW model, branching fractions and polarization fractions are firstly presented. Numerically, the CKM-favored (B) over bar (q)* -> DqDs* and D(q)p decays have branching fractions similar to 10 (8), which should be sought forwith priority and firstly observed by LHC and Belle-II. The (B) over bar (q)* -> DqK* and D(q)p decays are dominated by the longitudinal polarization states, while the parallel polarization fractions of (B) over bar (q)* -> D-q(D) over bar decays are comparable with the longitudinal ones; numerically,f(parallel to) vertical bar f(L) similar or equal to 95% and f(L) : F-parallel to similar or equal to 5 : 4. Some comparisons between (B) over bar (q)*(0) -> DqV and their corresponding (B) over bar (0)(q) -> D-q*V decays are performed, and the relation f(L,parallel to) ((B) over bar*(0) -> DV) similar or equal to f(L,parallel to) ((B) over bar (0) -> D*V is found. With the implication of SU(3) flavor symmetry, the ratios R-du and. R-ds are discussed and suggested to be verified experimentally.Mon, 21 Nov 2016 07:25:28 GMThttp://ir.itp.ac.cn/:80/handle/311006/211232016-11-21T07:25:28Z