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Observations on spontaneous chiral symmetry breaking and the mass gap of QCD in finite volume

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Communications in theoretical physics 2024年第9期76卷 44-49页

作者： Xiaolan Meng Bolun Hu Yi-Bo Yang University of Chinese Academy of Sciences School of Physical Sciences CAS Key Laboratory of theoretical physics Institute of Theoretical Physics Chinese Academy of Sciences school of Fundamental physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCAS International centre for theoretical physics Asia-Pacific

We present a lattice quantum chromodynamics(QCD) simulation with 2 + 1 + 1 flavor full QCD ensembles using near-physical quark masses and different spatial sizes L, at a ～ 0.055 *** results show that the scalar and pesudoscalar 2-point correlator with a valence pion mass of approximately 230 MeV become degenerated at L ≤ 1.0 fm, and such an observation suggests that the spontaneous chiral symmetry breaking disappears effectively at this point. At the same time, the mass gap between the nucleon and pion masses remains larger than ΛQCDin the entire L ∈ [0.2, 0.7] fm range.

关键词： chiral symmetry breaking confinement lattice QCD

Symbology of Feynman integrals from twistor geometries

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Science China(physics,Mechanics & Astronomy) 2024年第3期67卷 44-59页

作者： Song He Jiahao Liu Yichao Tang Qinglin Yang school of Fundamental physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China CAS Key Laboratory of theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China International centre for theoretical physics Asia-Pacific Beijing 100049 Peng Huanwu Center for Fundamental Theory Hefei 230026China school of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China

We study the symbology of planar Feynman integrals in dimensional regularization by considering geometric configurations in momentum twistor space corresponding to their leading singularities(LS). Cutting propagators in momentum twistor space amounts to intersecting lines associated with loop and external dual momenta, including the special line associated with the point at infinity, which breaks dual conformal symmetry. We show that cross-ratios of intersection points on these lines, especially those on the infinity line, naturally produce symbol letters for Feynman integrals in D = 4-2∈, which include and generalize their LS. At one loop, we obtain all symbol letters using intersection points from quadruple cuts for integrals up to pentagon kinematics with two massive corners, which agree perfectly with canonical differential equation(CDE) results. We then obtain all two-loop letters, for up to four-mass box and one-mass pentagon kinematics, by considering more intersections arising from two-loop cuts. Finally we comment on how cluster algebras appear from this construction, and importantly how we may extend the method to non-planar integrals.

关键词： Feynman integrals symbol letters twistor geometry

Search for production of dark fermion candidates in association with heavy neutral gauge boson decaying to dimuon in proton-proton collisions at√s=8 TeV using CMS open data

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Chinese physics C 2024年第4期48卷 6-13页

作者： Y.Mahmoud H.Abdallah M.T.Hussein S.Elgammal centre for theoretical physics The British University in EgyptEgypt physics Department Faculty of ScienceCairo UniversityEgypt

In this study,we conducted a search for dark matter using a part of the data recorded by the CMS experiment during run-I of the LHC in 2012 with a center of mass energy of 8 TeV and an integrated luminosity of 11.6 fb−*** data were gathered from the CMS open *** matter,in the framework of the simplified model(mono-Z′),can be produced from proton-proton collisions in association with a new hypothetical gauge boson,Z′.Thus,the search was conducted in the dimuon plus large missing transverse momentum *** benchmark scenario of mono-Z′,which is known as light vector,was used for interpreting the CMS open *** evidence of dark matter was observed,and exclusion limits were set on the masses of dark matter and Z′at 95%confidence level.

关键词： dark matter large hadron collider CMS open data search for new physics dark fermion

An improved bound on accelerated light dark matter

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Science China(physics,Mechanics & Astronomy) 2024年第2期67卷 105-118页

作者： Liangliang Su Lei Wu Bin Zhu Department of physics and Institute of theoretical physics Nanjing Normal UniversityNanjing 210023China school of physics Yantai UniversityYantai 264005China

Light(sub-GeV)dark matter has gained increasing interest in terms of direct *** dark matter is a promising candidate that can generate detectable nuclear recoil energy within the sub-GeV *** of the large kinetic energy,its interactions with the nucleus are predominantly governed by inelastic scattering,including quasi-elastic and deep inelastic *** this work,we calculated the inelastic effects in dark matter-Earth scattering mediated by a vector *** analysis revealed that the impact of inelastic scattering relies on the mediator mass and the kinetic energy spectrum of dark *** results exhibited considerable disparity:the upper bounds of the exclusion limit for the spin-independent cross-section between accelerated dark matter and nuclei via a heavy mediator differ by several tens of times when inelastic scattering is considered.

关键词： accelerated dark matter inelastic scattering direct detection experiment

Is Yang-Mills theory unitary in fractional spacetime dimensions?

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Science China(physics,Mechanics & Astronomy) 2024年第7期67卷 59-64页

作者： Qingjun Jin Ke Ren Gang Yang Rui Yu Graduate school of China Academy of Engineering physics Beijing 100193China school of physics and Astronomy Sun Yat-Sen UniversityZhuhai 519082China CAS Key Laboratory of theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China school of Fundamental physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China International centre for theoretical physics Asia-Pacific Hangzhou 310024China school of Physical Science and Technology Inner Mongolia UniversityHohhot 010021China Beijing Computational Science Research Center Beijing 100193China

We present concrete evidence that Yang-Mills theory exhibits non-unitarity in non-integer spacetime *** violation of unitarity stems from evanescent operators that,while vanishing in four dimensions,are non-zero in general d *** demonstrate that these evanescent operators lead to the emergence of both negative-norm states and complex anomalous dimensions.

关键词： gauge field theories field theories in dimensions other than four renormalization

Supermassive black holes triggered by QCD axion bubbles

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Communications in theoretical physics 2024年第5期76卷 134-139页

作者： Hai-Jun Li Ying-Quan Peng Wei Chao Yu-Feng Zhou Key Laboratory of theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China school of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China school of Fundamental physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International centre for theoretical physics Asia-Pacific Beijing/HangzhouChina

Supermassive black holes(SMBHs)are ubiquitous in the center of galaxies,although the origin of their massive seeds is still *** this paper,we investigate the formation of SMBHs from the quantum chromodynamics(QCD)axion *** this case,primordial black holes(PBHs)are considered as the seeds of SMBHs,which are generated from the QCD axion bubbles due to an explicit Peccei–Quinn(PQ)symmetry breaking after *** QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase *** consider a general case in which the axion bubbles are formed with the bubble effective angle θ_(eff)∈(0,π],leading to the minimum PBH mass∼■(10^(4)−10^(7))M⊙for the axion decay constant f_(a)∼■(10^(16))*** PBHs at this mass region may account for the seeds of SMBHs.

关键词： supermassive black holes primordial black holes quantum chromodynamics axion

Primordial black holes and curvature perturbations from false vacuum islands

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Science China(physics,Mechanics & Astronomy) 2024年第9期67卷 58-72页

作者： Rong-Gen Cai Yu-Shi Hao Shao-Jiang Wang school of Physical Science and Technology Ningbo UniversityNingbo 315211China CAS Key Laboratory of theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China school of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Asia Pacific Center for theoretical physics Pohang 37673Republic of Korea

Recently,much attention has been focused on the false vacuum islands that are flooded by an expanding ocean of true-vacuum bubbles slightly later than most of the other parts of the *** delayed decay regions will accumulate locally larger vacuum energy density by staying in the false vacuum longer than those already transited into the true vacuum.A false vacuum island with thus acquired density contrast of a super-horizon size will evolve locally from radiation dominance to vacuum dominance,creating a local baby Universe that can be regarded effectively as a local closed *** such density contrasts of super-horizon sizes can ever grow large enough to exceed the threshold of gravitational collapse,primordial black holes will form similar to those collapsing curvature perturbations on super-horizon scales induced by small-scale enhancements during *** not,such density contrasts can still induce curvature perturbations potentially observable *** this paper,we revisit and elaborate on the generations of primordial black holes and curvature perturbations from delayed-decayed false vacuum islands during asynchronous first-order phase transitions with fitting formulas convenient for future model-independent studies.

关键词： first-order phase transitions primordial black holes curvature perturbations

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Revisiting the N = 1 supersymmetric trinification models from intersecting D6-branes

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Communications in theoretical physics 2024年第9期76卷 29-38页

作者： Adeel Mansha Tianjun Li Mudassar Sabir Department of physics Zhejiang Normal University Zhejiang Institute of Photoelectronics Zhejiang Normal University centre For High Energy physics University of the Punjab CAS Key Laboratory of theoretical physics Institute of Theoretical Physics Chinese Academy of Sciences school of Physical Sciences University of Chinese Academy of Sciences school of physics University of Electronic Science and Technology of China

We revisit the construction of the N= 1 supersymmetric trinification models with gauge group U（3）C× U（3）L× U（3）Rin Type ⅡA string theory on T6（Z2×Z2）orientifold with intersecting D6-branes. The non-trivial K-theory conditions and tadpole cancellation conditions severely restrict the number of allowed models even for the case of rectangular two-tori. Using a supervised search algorithm, we find a few four-family models where the highest wrapping number is 2. For these models, we present the complete particle spectra and the gauge coupling relations at the string-scale.

关键词： D branes string phenomenology trinification

Energy-information trade-off induces continuous and discontinuous phase transitions in lateral predictive coding

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Science China(physics,Mechanics & Astronomy) 2024年第6期67卷 79-85页

作者： Zhen-Ye Huang Ruyi Zhou Miao Huang Hai-Jun Zhou Key Laboratory for theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China school of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China school of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China Minjiang Collaborative Center for theoretical physics Minjiang UniversityFuzhou 350108China

Lateral predictive coding is a recurrent neural network that creates energy-efficient internal representations by exploiting statistical regularity in sensory ***,we analytically investigate the trade-off between information robustness and energy in a linear model of lateral predictive coding and numerically minimize a free energy *** observed several phase transitions in the synaptic weight matrix,particularly a continuous transition that breaks reciprocity and permutation symmetry and builds cyclic dominance and a discontinuous transition with the associated sudden emergence of tight balance between excitatory and inhibitory *** optimal network follows an ideal gas law over an extended temperature range and saturates the efficiency upper bound of energy *** results provide theoretical insights into the emergence and evolution of complex internal models in predictive processing systems.

关键词： predictive coding recurrent neural network phase transition internal model free energy