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Running of effective dimension and cosmological entropy in early universe

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arXiv 2020年

作者： Xiao, Yong Key Laboratory of High-precision Computation and Application of Quantum Field Theory of Hebei Province College of Physical Science and Technology Hebei University Baoding071002 China Department of Physics and Astronomy University of Sussex BrightonBN1 9QH United Kingdom

In this paper, we suggest that the early universe starts from a high-energetic state with a two dimensional description and the state recovers to be four dimensional when the universe evolves into the radiation dominated phase. This scenario is consistent with the recent viewpoint that quantum gravity should be effectively two dimensional in the ultraviolet and recovers to be four dimensional in the infrared. A relationship has been established between the running of effective dimension and that of the entropy inside particle horizon of the universe, i.e., as the effective dimension runs from two to four, the corresponding entropy runs from the holographic entropy to the normal entropy appropriate to radiation. These results can be generalized to higher dimensional cases. Copyright © 2020, The Authors. All rights reserved.

关键词： Entropy

Probing the population of extreme-mass-ratio inspirals with TianQin

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Physical Review D 2025年第10期111卷 103008-103008页

作者： Hui-Min Fan Xiang-Yu Lyu Jian-dong Zhang Yi-Ming Hu Rong-Jia Yang Tai-Fu Feng Department of Physics Hebei University Baoding 071002 China Hebei Key Laboratory of High-precision Computation and Application of Quantum Field Theory Baoding 071002 China and Hebei Research Center of the Basic Discipline for Computational Physics Baoding 071002 China School of Physics and Astronomy Sun Yat-sen University (Zhuhai Campus) Zhuhai 519082 China and MOE Key Laboratory of TianQin Mission TianQin Research Center for Gravitational Physics Frontiers Science Center for TianQin Gravitational Wave Research Center of CNSA Sun Yat-sen University (Zhuhai Campus) Zhuhai 519082 China

Extreme-mass-ratio inspirals (EMRIs), consisting of a massive black hole (MBH) and a stellar compact object, are one of the most important sources for spaceborne gravitational wave detectors like TianQin. Their population study can be used to constrain astrophysical models that interpret the EMRI formation mechanisms. In this paper, as an initial attempt, we employ a parametrization method to describe the EMRI population model in the loss cone formation channel. This approach, however, can be extended to other models, such as the accretion disc-driven formation channel. We present the phenomenological characteristic of the MBH mass, spin, and redshift distributions. Then, we investigate the posterior distribution of the hyperparameters that describe this population model. The optimistic results show that TianQin could recover almost all the posterior of the hyperparameters within a 1σ confidence interval. The hyperparameters α1, α2, and b, which describe the MBH mass distribution, could be measured with an accuracy of 46.4%, 12.6%, and 3%, respectively. The hyperparameters μz and σz, which describe the redshift distribution, could be measured with an accuracy of 15.4% and 21.1%. With this estimation accuracy, the EMRI population characteristics can be effectively demonstrated, potentially serving as evidence for EMRI formation in the future studies. Furthermore, with an increasing number of detectable events, the parameter estimation for the hyperparameters will improve and the confidence intervals will be narrowed.

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125 GeV Higgs boson decay to a pair of muons in the µνSSM

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arXiv 2020年

作者： Zhang, Hai-Bin Niu, Zhi-Min Sun, Ke-Sheng Zhao, Shu-Min Wang, Ying-Long Feng, Tai-Fu Department of Physics Hebei University Baoding071002 China Key Laboratory of High-precision Computation and Application of Quantum Field Theory of Hebei Province Baoding071002 China Department of Physics Baoding University Baoding071000 China College of Physics Chongqing University Chongqing400044 China

Recently, the ATLAS and CMS Collaborations measured the 125 GeV Higgs boson decay to a pair of muons h → µµ¯, which reported the signal strength relative to the standard model (SM) prediction is 1.2 ± 0.6 and 1.19+0.40+0.15−0.39−0.14, respectively. In this work, we investigate the 125 GeV Higgs boson decay h → µµ¯ at one-loop level in the µ from ν Supersymmetric Standard Model (µνSSM). Compared to the SM prediction, the decay width of h → µµ¯ in the µνSSM can boost up about 10%, considering the constraint from the muon anomalous magnetic dipole moment. Copyright © 2020, The Authors. All rights reserved.

关键词： Supersymmetry

Λc(2910) and Λc(2940) as the conventional baryons dressed with the D∗N channel

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arXiv 2022年

作者： Zhang, Zi-Le Liu, Zhan-Wei Luo, Si-Qiang Wang, Fu-Lai Wang, Bo Xu, Hao School of Physical Science and Technology Lanzhou University Lanzhou730000 China Research Center for Hadron Csr Physics Lanzhou University Institute of Modern Physics of Cas Lanzhou730000 China Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Province Frontiers Science Center for Rare Isotopes Lanzhou University Lanzhou730000 China School of Physical Science and Technology Hebei University Baoding071002 China Key Lab. of High-precision Computation and Application of Quantum Field Theory of Hebei Province Baoding071002 China Research Center for Computational Physics of Hebei Province Baoding071002 China Institute of Theoretical Physics College of Physics and Electronic Engineering Northwest Normal University Lanzhou730070 China Lanzhou Center for Theoretical Physics Lanzhou University Lanzhou730000 China

In this work, we treat Λc(2910)+and Λc(2940)+as the conventional udc cores dressed with the D∗N channel. We provide a possible interpretation to both Λc(2910)+and Λc(2940)+within the same framework. In the study, we consider not only the effects between the conventional triquark core and the D∗N channel but also the D∗N-D∗N interactions. The mass of Λcstate with JP= 1/2-is larger than that with JP= 3/2-in this unquenched picture, which is very different from the prediction of the conventional quenched quark model. Based on the mass spectrum, the spin-parity of Λc(2940)+is more likely to be 1/2-while Λc(2910)+prefers 3/2-. We look forward to the future experiments can test our results with more precise experimental data. Copyright © 2022, The Authors. All rights reserved.

关键词： Mass spectrometry

e+e- → hhZ in the B-LSSM

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arXiv 2020年

作者： Cui, Dan-Dan Feng, Tai-Fu Yan, Yu-Li Zhang, Hai-Bin Ning, Guo-Zhu Yang, Jin-Lei Department of Physics Hebei University Baoding071002 China Key Laboratory of High-precision Computation and Application of Quantum Field Theory of Hebei Province Baoding071002 China Department of Physics Chongqing University Chongqing400044 China CAS Key Laboratory of Theoretical Physics School of Physical Sciences University of Chinese Academy of Sciences Beijing100049 China

The double Higgs boson production through e+e− → hhZ is analyzed in the minimal supersymmetric extension of the Standard Model(SM) with the local gauge symmetry U(1)B−L, where h denotes the lightest Higgs boson with 125 GeV. Considering the constraints from the updated prediction data, we find that the production cross section of this process in the model depends on some parameters strongly. Copyright © 2020, The Authors. All rights reserved.

关键词： Bosons

Electron and muon (g − 2) in the B-LSSM

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arXiv 2020年

作者： Yang, Jin-Lei Feng, Tai-Fu Zhang, Hai-Bin Department of Physics Hebei University Baoding071002 China Key Laboratory of High-precision Computation and Application of Quantum Field Theory of Hebei Province Baoding071002 China CAS Key Laboratory of Theoretical Physics School of Physical Sciences University of Chinese Academy of Sciences Beijing100049 China Department of Physics Chongqing University Chongqing401331 China

The theoretical predictions in the standard model (SM) and measurements on the anomalous magnetic dipole moments (MDM) of muon and electron have great precision, hence the MDMs of muon and electron have close relation with the new physics (NP) beyond the SM. Recently, a negative ∼ 2.4σ discrepancy between the measured electron MDM and the SM prediction results from a recent improved determination of the fine structure constant. Combined with the long-lasting muon MDM discrepancy which is about ∼ 3.7σ, it is difficult to explain both the magnitude and opposite signs of the deviations in a consistent model, without introducing large flavour-violating effects. The analysis shows that they can be explained in the minimal supersymmetric extension (MSSM) of the SM with local B − L gauge symmetry (B-LSSM). Comparing with the MSSM, new parameters in the B-LSSM can affect the theoretical predictions on lepton MDMs, and the effects of them are explored. Copyright © 2020, The Authors. All rights reserved.

关键词： Electrons

Generating Function of Loop Reduction by Baikov Representation

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arXiv 2025年

作者： Hu, Chang Li, Wen-Di Li, Xiang College of Physics Science and Technology Hebei University Baoding071002 China Hebei Key Laboratory of High-precision Computation and Application of Quantum Field Theory Baoding071002 China Hebei Research Center of the Basic Discipline for Computational Physics Baoding071002 China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study UCAS Hangzhou310024 China University of Chinese Academy of Sciences Beijing100049 China Institute of Theoretical Physics Chinese Academy of Sciences Beijing100190 China School of Physics Peking University Beijing100871 China

In this work, we study the computation of reduction coefficients for multi-loop Feynman integrals using generating functions constructed within the Baikov representation. Compared with traditional Feynman rules, the Baikov formalism offers a more structured and transparent framework, especially well-suited for analyzing the reduction problem. We emphasize that, in a variety of nontrivial cases—including several one-loop and selected multi-loop examples—the generating functions can be explicitly computed in closed form, often involving hypergeometric or elementary functions. These analytic expressions significantly simplify the determination of reduction coefficients and enhance their interpretability. The results demonstrate the practicality and potential of this approach, suggesting that the use of generating functions within the Baikov representation can serve as a powerful and flexible tool in modern Feynman integral reduction, even though its full scope for generic multi-loop topologies remains to be explored. © 2025, CC0.

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A proposal to the ‘1 /2 vs. 3 /2 puzzle’

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arXiv 2020年

作者： Li, Qiang Feng, Wei Wang, Guo-Li School of Physical Science and Technology Northwestern Polytechnical University Xi’an710072 China School of Electronic Engineering Xidian University Xi’an710071 China Department of Physics Hebei University Baoding071002 China Key Laboratory of High-precision Computation and Application of Quantum Field Theory of Hebei Province Baoding071002 China

We reconsider the semileptonic decays of B → D1(0)lν¯l. The previous theoretical calculations predict a significantly smaller rate for the semileptonic decay of B to D10 (Jl = 21) compared with that to the D1(Jl = 32), which is not consistent with the current experimental data. This conflict is the so-called ‘12 vs. 32 puzzle’. In this work, we propose a simple scheme to fix this problem, where we suppose that the strong eigenstates D1(0) do not coincide with the eigenstate of the weak interaction, since no experimental results show the weak and the strong interactions have to share the same eigenstates. Within the framework of this tentative scheme, meson B first weakly decays to the weak eigenstates Dα(β) and then the latter are detected as the D1(0) by the strong products D∗π. We predict that there exist two new particles Dα(β) with JP = 1+ which were not previously identified. The good performance of the new scheme in describing the experimental data may hint at new symmetry in the weak decays of Bq to 1+ heavy-light mesons. To test the scheme proposed here, we suggest an experiment to detect the difference in the invariant mass spectra of D1 reconstructed from the B weak decay and from the strong decay products. Copyright © 2020, The Authors. All rights reserved.

关键词： Mass spectrometry

Revisit the isospin violating decays of X(3872)

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arXiv 2021年

作者： Meng, Lu Wang, Guang-Juan Wang, Bo Zhu, Shi-Lin Ruhr-Universität Bochum Fakultät für Physik und Astronomie Institut für Theoretische Physik II BochumD-44780 Germany Advanced Science Research Center Japan Atomic Energy Agency Ibaraki Tokai319-1195 Japan School of Physical Science and Technology Hebei University Baoding071002 China Key Laboratory of High-precision Computation and Application of Quantum Field Theory of Hebei Province Baoding071002 China School of Physics and Center of High Energy Physics Peking University Beijing100871 China

In this work, we revisit the isospin violating decays of X(3872) in a coupled-channel effective field theory. In the molecular scheme, the X(3872) is interpreted as the bound state of D¯ ∗0D0/D¯ 0D∗0 and D∗−D+/D−D∗+ channels. In a cutoff-independent formalism, we relate the coupling constants of X(3872) with the two channels to the molecular wave function. The isospin violating decays of X(3872) are obtained by two equivalent approaches, which amend some deficiencies about this issue in literature. In the quantum field theory approach, the isospin violating decays arise from the coupling constants of X(3872) to two di-meson channels. In the quantum mechanics approach, the isospin violating is attributed to wave functions at the origin. We illustrate that how to cure the insufficient results in literature. Within the comprehensive analysis, we bridge the isospin violating decays of X(3872) to its inner structure. Our results show that the proportion of the neutral channel in X(3872) is over 80%. As a by-product, we calculate the strong decay width of X(3872) → D¯ 0D0π0 and radiative one X(3872) → D¯ 0D0γ. The strong decay width and radiative decay width are about 30 keV and 10 keV, respectively, for the binding energy from −300 keV to −50 keV. Copyright © 2021, The Authors. All rights reserved.

关键词： Wave functions