ITP OpenIR
http://ir.itp.ac.cn/:80
中国科学院理论物理研究所Fri, 16 Apr 2021 08:10:03 GMT2021-04-16T08:10:03ZFast and accurate determination of phase transition temperature via individual generalized canonical ensemble simulation
http://ir.itp.ac.cn/:80/handle/311006/27256
Title: Fast and accurate determination of phase transition temperature via individual generalized canonical ensemble simulation
Authors: Shao, Ming-Zhe; Wang, Yan-Ting; Zhou, Xin
Description: It is very important to determine the phase transition temperature, such as the water/ice coexistence temperature in various water models, via molecular simulations. We show that a single individual direct simulation is sufficient to get the temperature with high accuracy and small computational cost based on the generalized canonical ensemble (GCE). Lennard-Jones fluids, the atomic water models, such as TIP4P/2005, TIP4P/ICE, and the mW water models are applied to illustrate the method. We start from the coexistent system of the two phases with a plane interface, then equilibrate the system under the GCE, which can stabilize the coexistence of the phases, to directly derive the phase transition temperature without sensitive dependence on the applied parameters of the GCE and the size of the simulation systems. The obtained result is in excellent agreement with that in literatures. These features make the GCE approach in determining the phase transition temperature of systems be robust, easy to use, and particularly good at working on computationally expensive systems.Thu, 26 Nov 2020 02:50:41 GMThttp://ir.itp.ac.cn/:80/handle/311006/272562020-11-26T02:50:41ZExtraction of N D scattering lengths from the Lambda(b) -> pi(-)pD(0) decay and properties of the Sigma(c)(2800)(+)
http://ir.itp.ac.cn/:80/handle/311006/27255
Title: Extraction of N D scattering lengths from the Lambda(b) -> pi(-)pD(0) decay and properties of the Sigma(c)(2800)(+)
Authors: Sakai, Shuntaro; Guo, Feng-Kun; Kubis, Bastian
Description: The isovector and isoscalar NDs-wave scattering lengths are extracted by fitting to the LHCb data of the pD(0) invariant-mass distribution in the decay Lambda(b) -> pi(-) pD(0), making use of the cusp effect at the nD(+) threshold. The analysis is based on a coupled-channel nonrelativistic effective field theory. We find that the real part of the isovector ND scattering length is unnaturally large due to the existence of a near-threshold state with a mass around 2.8GeV. The state is consistent with the Sigma(c)(2800)(+) resonance observed at Belle. Our results suggest that it couples strongly to the ND channel in an s-wave, and that its quantum numbers are J(P)= 1/2(-). The strong cusp behavior at the nD(+) threshold can be verified using updated LHCb data. (C) 2020 The Author(s). Published by Elsevier B.V.Thu, 26 Nov 2020 02:50:41 GMThttp://ir.itp.ac.cn/:80/handle/311006/272552020-11-26T02:50:41ZExploring Possible Triangle Singularities in the Xi(-)(b) -> K- J/psi Lambda Decay
http://ir.itp.ac.cn/:80/handle/311006/27250
Title: Exploring Possible Triangle Singularities in the Xi(-)(b) -> K- J/psi Lambda Decay
Authors: Shen, Chao-Wei; Jing, Hao-Jie; Guo, Feng-Kun; Wu, Jia-Jun
Description: We analyze possible singularities in the J/psi Lambda invariant mass distribution of the Xi(-)(b) -> K- J/psi Lambda process via triangle loop diagrams. Triangle singularities in the physical region are found in 18 different triangle loop diagrams. Among those with Xi*-charmonium-L intermediate states, the one from the chi(c1)Xi(2120)Lambda loop, which is located around 4628 MeV, is found the most likely to cause observable effects. One needs S- and P-waves in chi(c1)Lambda and J/psi Lambda systems, respectively, when the quantum numbers of these systems are 1/2(+) or 3/2(+). When the quantum numbers of the Xi(2120) are J(P) = 1/2(+), 1/2 or 3/2(+), the peak structure should be sharper than the other J(P) choices. This suggests that although the whole strength is unknown, we should pay attention to the contributions from the Xi*-charmonium-L triangle diagram if structures are observed in the J/psi Lambda invariant mass spectrum experimentally. In addition, a few triangle diagrams with the D*(s1) (2700) as one of the intermediate particles can also produce singularities in the J/psi Lambda distribution, but at higher energies above 4.9 GeV.Thu, 26 Nov 2020 02:50:39 GMThttp://ir.itp.ac.cn/:80/handle/311006/272502020-11-26T02:50:39ZExplaining (g-2)(mu,e), the KOTO anomaly, and the MiniBooNE excess in an extended Higgs model with sterile neutrinos
http://ir.itp.ac.cn/:80/handle/311006/27249
Title: Explaining (g-2)(mu,e), the KOTO anomaly, and the MiniBooNE excess in an extended Higgs model with sterile neutrinos
Authors: Dutta, Bhaskar; Ghosh, Sumit; Li, Tianjun
Description: We consider a simple extension of the Standard Model (SM) by a complex scalar doublet and a singlet along with three sterile neutrinos. The sterile neutrinos mix with the SM neutrinos to produce three light neutrino states consistent with the oscillation data and three heavy sterile states. The lightest sterile neutrino has lifetime longer than the age of the Universe and can provide correct dark matter relic abundance. Utilizing tree-level flavor changing interactions of a light scalar with mass similar to O(100) MeV along with sterile neutrinos, we can explain the anomalous magnetic moments of both muon and electron, KOTO anomalous events and the MiniBooNE excess simultaneously.Thu, 26 Nov 2020 02:50:38 GMThttp://ir.itp.ac.cn/:80/handle/311006/272492020-11-26T02:50:38ZEquation of state and chiral transition in soft-wall AdS/QCD with a more realistic gravitational background*
http://ir.itp.ac.cn/:80/handle/311006/27246
Title: Equation of state and chiral transition in soft-wall AdS/QCD with a more realistic gravitational background*
Authors: Fang, Zhen; Wu, Yue-Liang
Description: We construct an improved soft-wall AdS/QCD model with a cubic coupling term of the dilaton and the bulk scalar field. The background fields in this model are solved by the Einstein-dilaton system with a nontrivial dilaton potential, which has been shown to reproduce the equation of state from the lattice QCD with two flavors. The chiral transition behaviors are investigated in the improved soft-wall AdS/QCD model with the solved gravitational background, and the crossover transition can be realized. Our study provides the possibility to address the deconfining and chiral phase transitions simultaneously in the bottom-up holographic framework.Thu, 26 Nov 2020 02:50:37 GMThttp://ir.itp.ac.cn/:80/handle/311006/272462020-11-26T02:50:37ZEmergence of Maximal Symmetry
http://ir.itp.ac.cn/:80/handle/311006/27239
Title: Emergence of Maximal Symmetry
Authors: Csaki, Csaba; Ma, Teng; Shu, Jing; Yu, Jiang-Hao
Description: An emergent global symmetry of the composite sector (called maximal symmetry) can soften the ultraviolet behavior of the Higgs potential and also significantly modify its structure. We explain the conditions for the emergence of maximal symmetry as well as its main consequences and present two simple implementations. In both cases the emergence of maximal symmetry is enforced by the structure of the gauge symmetries.Thu, 26 Nov 2020 02:50:34 GMThttp://ir.itp.ac.cn/:80/handle/311006/272392020-11-26T02:50:34ZEFTs meet Higgs nonlinearity, compositeness and (neutral) naturalness
http://ir.itp.ac.cn/:80/handle/311006/27235
Title: EFTs meet Higgs nonlinearity, compositeness and (neutral) naturalness
Authors: Li, Hao-Lin; Xu, Ling-Xiao; Yu, Jiang-Hao; Zhu, Shou-hua
Description: Composite Higgs and neutral-naturalness models are popular scenarios in which the Higgs boson is a pseudo Nambu-Goldstone boson (PNGB), and naturalness problem is addressed by composite top partners. Since the standard model effective field theory (SMEFT) with dimension-six operators cannot fully retain the information of Higgs nonlinearity due to its PNGB nature, we systematically construct low energy Lagrangian in which the information of compositeness and Higgs nonlinearity are encoded in the form factors, the two-point functions in the top sector. We classify naturalness conditions in various scenarios, and first present these form factors in composite neutral naturalness models. After extracting out Higgs effective couplings from these form factors and performing the global fit, we find the value of Higgs top coupling could still be larger than the standard model one if the top quark is embedded in the higher dimensional representations. Also we find the impact of Higgs nonlinearity is enhanced by the large mass splitting between composite states. In this case, pattern of the correlation between the tt<overbar></mml:mover>h and t<mml:mover accent="true">t<mml:mo stretchy="true"><overbar></mml:mover>hh couplings is quite different for the linear and nonlinear Higgs descriptions.Thu, 26 Nov 2020 02:50:33 GMThttp://ir.itp.ac.cn/:80/handle/311006/272352020-11-26T02:50:33ZEffects of the merger history on the merger rate density of primordial black hole binaries
http://ir.itp.ac.cn/:80/handle/311006/27230
Title: Effects of the merger history on the merger rate density of primordial black hole binaries
Authors: Liu, Lang; Guo, Zong-Kuan; Cai, Rong-Gen
Description: We develop a formalism to calculate the merger rate density of primordial black hole binaries with a general mass function, by taking into account the merger history of primordial black holes. We apply the formalism to three specific mass functions: the monochromatic, power-law and log-normal cases. In the former case, the merger rate density is dominated by the single-merger events, while in the latter two cases, the contribution of the multiple-merger events on the merger rate density cannot be ignored. The effects of the merger history on the merger rate density depend on the mass function.Thu, 26 Nov 2020 02:50:31 GMThttp://ir.itp.ac.cn/:80/handle/311006/272302020-11-26T02:50:31ZEffects of -meson on the EOS, Maximum Masses, and Radii of Hyperon Stars
http://ir.itp.ac.cn/:80/handle/311006/27229
Title: Effects of -meson on the EOS, Maximum Masses, and Radii of Hyperon Stars
Authors: Biswal, S. K.; Patra, S. K.; Zhou, Shan-Gui
Description: The relativistic mean field (RMF) model is considered as one of the best methods to study the nuclear system that has a high degree of isospin asymmetry and baryon density. In the present contribution, we take 25 well-known parameter sets of the RMF model to discuss the parametric dependence of the neutron and hyperon star properties. Various properties of the canonical star are discussed and only a few parameter sets are found to satisfy both the astrophysical and nuclear matter constraints. We add both and ?* strange mesons to the ?-?-? model. Effects of the -meson on the equation of state and maximum mass of the hyperon star are discussed in detail. -meson affects the threshold density of hyperon production and pushes the hyperon production to a higher density. Effects of the hyperon?meson coupling constants on the maximum mass?radius profile and strangeness content of the hyperon star are discussed in the ?-?-?--?* model.Thu, 26 Nov 2020 02:50:30 GMThttp://ir.itp.ac.cn/:80/handle/311006/272292020-11-26T02:50:30ZEffects of finite-range interactions on the one-electron spectral properties of TTF-TCNQ
http://ir.itp.ac.cn/:80/handle/311006/27228
Title: Effects of finite-range interactions on the one-electron spectral properties of TTF-TCNQ
Authors: Carmelo, Jose M. P.; Cadez, Tilen; Campbell, David K.; Sing, Michael; Claessen, Ralph
Description: The electronic dispersions of the quasi-one-dimensional organic conductor TTF-TCNQ are studied by angle-resolved photoelectron spectroscopy (ARPES) with higher angular resolution and accordingly smaller step width than in previous studies. Our experimental results suggest that a refinement of the single-band 1D Hubbard model that includes finite-range interactions is needed to explain these photoemission data. To account for the effects of these finite-range interactions we employ a mobile quantum impurity scheme that describes the scattering of fractionalized particles at energies above the standard Tomonaga-Luttinger liquid limit. Our theoretical predictions agree quantitatively with the location in the (k, omega) plane of the experimentally observed ARPES structures at these higher energies. The nonperturbative microscopic mechanisms that control the spectral properties are found to simplify in terms of the exotic scattering of the charge fractionalized particles. We find that the scattering occurs in the unitary limit of (minus) infinite scattering length, which limit occurs within neutron-neutron interactions in shells of neutron stars and in the scattering of ultracold atoms but not in perturbative electronic condensed-matter systems. Our results provide important physical information on the exotic processes involved in the finite-range electron interactions that control the high-energy spectral properties of TTF-TCNQ. Our results also apply to a wider class of 1D and quasi-1D materials and systems that are of theoretical and potential technological interest.Thu, 26 Nov 2020 02:50:30 GMThttp://ir.itp.ac.cn/:80/handle/311006/272282020-11-26T02:50:30Z