The European Physical Journal C最新文献_第8页

Search for baryon junctions in e+A collisions at the electron ion collider 在电子离子对撞机中寻找e+A碰撞中的重子结

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2024-12-27 DOI: 10.1140/epjc/s10052-024-13702-9

Niseem Magdy, Abhay Deshpande, Roy Lacey, Wenliang Li, Prithwish Tribedy, Zhangbu Xu

{"title":"Search for baryon junctions in e+A collisions at the electron ion collider","authors":"Niseem Magdy, Abhay Deshpande, Roy Lacey, Wenliang Li, Prithwish Tribedy, Zhangbu Xu","doi":"10.1140/epjc/s10052-024-13702-9","DOIUrl":"10.1140/epjc/s10052-024-13702-9","url":null,"abstract":"<div><p>Constituent quarks in a nucleon are the essential elements in the standard “quark model” associated with the electric charge, spin, mass, and baryon number of a nucleon. Quantum chromodynamics (QCD) describes nucleon as a composite object containing current quarks (valence quarks and sea (anti-)quarks) and gluons. These subatomic elements and their interactions are known to contribute in complex ways to the overall nucleon spin and mass. In the early development of QCD theory in the 1970s, an alternative hypothesis postulated that the baryon number might manifest itself through a non-perturbative configuration of gluon fields forming a Y-shaped topology known as the gluon junction. In this work, we propose to test such hypothesis by measuring (i) the Regge intercept of the net-baryon distributions for <i>e</i>+(<i>p</i>)Au collisions, (ii) baryon and charge transport in the isobaric ratio between <i>e</i>+Ru and <i>e</i>+Zr collisions, and (iii) target flavor dependence of proton and antiproton yields at large rapidity, transported from the hydrogen and deuterium targets in <span>(e+p)</span>(d) collisions. Our study indicates that these measurements at the EIC can help determine what carries the baryon number.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13702-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Circular light orbits of a general, static, and spherical symmetrical wormhole with (Z_2) symmetry 圆形光轨道的一般，静态和球形对称虫洞(Z_2)对称

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2024-12-27 DOI: 10.1140/epjc/s10052-024-13696-4

Naoki Tsukamoto

{"title":"Circular light orbits of a general, static, and spherical symmetrical wormhole with (Z_2) symmetry","authors":"Naoki Tsukamoto","doi":"10.1140/epjc/s10052-024-13696-4","DOIUrl":"10.1140/epjc/s10052-024-13696-4","url":null,"abstract":"<div><p>Recently, the ring images or the shadow images of the centers of the galaxy M87 and the Milky way have been reported by Event Horizon Telescope Collaboration. It is believed that the ring images imply that the central objects form unstable light circular orbits. Some of wormholes with <span>(Z_2)</span> symmetry against a throat are wrongly excluded from the candidates at the centers of M87 and the Milky way due to the overlooking the unstable light circular orbits on the throat. A general asymptotically-flat, static, and spherical symmetrical wormhole without a thin shell has at least one unstable circular light orbit at the throat or elsewhere. If the wormhole has <span>(Z_2)</span> symmetry against the throat, it has the unstable circular light orbits on the throat or it has stable circular light orbits on the throat and unstable ones near the throat. We need to analyze the throat carefully to make sure we do not unfairly rule out the <span>(Z_2)</span>-symmetrical wormholes. In this study, we categorize the numbers of the circular light orbits of the <span>(Z_2)</span>-symmetrical wormhole and their stability from the derivatives of an effective potential at the throat and we investigate the circular light orbits around a Simpson–Visser black-bounce spacetime, a Damour–Solodukhin wormhole spacetime, a Reissner–Nordström black-hole-like wormhole spacetime or a charged Damour–Solodukhin wormhole spacetime as examples. We give complete treatments including degenerated circular light orbits made from more than one stable and unstable circular light orbits on and off the throat.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13696-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A model-independent compact dynamical system formulation for exploring bounce and cyclic cosmological evolutions in (f, (R)) gravity 用于探索(f, (R))重力中弹跳和循环宇宙学演化的模型无关的紧致动力系统公式

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2024-12-26 DOI: 10.1140/epjc/s10052-024-13707-4

Saikat Chakraborty, Charlotte Louw, A. S. Agrawal, Peter K. S. Dunsby

引用次数: 0

Strong-field QED effects on polarization states in dipole and quadrudipole pulsar emissions 强场QED对偶极和四偶极脉冲星发射偏振态的影响

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2024-12-26 DOI: 10.1140/epjc/s10052-024-13662-0

Dong-Hoon Kim, Chul Min Kim, Sang Pyo Kim

{"title":"Strong-field QED effects on polarization states in dipole and quadrudipole pulsar emissions","authors":"Dong-Hoon Kim, Chul Min Kim, Sang Pyo Kim","doi":"10.1140/epjc/s10052-024-13662-0","DOIUrl":"10.1140/epjc/s10052-024-13662-0","url":null,"abstract":"<div><p>Highly magnetized neutron stars have quantum refraction effects on pulsar emission due to the non-linearity of the quantum electrodynamics (QED) action. In this paper, we investigate the evolution of the polarization states of pulsar emission under the quantum refraction effects, combined with the dependence on the emission frequency, for dipole and quadrudipole pulsar models; we solve a system of evolution equations of the Stokes vector, where the birefringent vector, in which such effects are encoded, acts on the Stokes vector. At a fixed emission frequency, depending on the magnitude of the birefringent vector, dominated mostly by the magnetic field strength, the evolution of the Stokes vector largely exhibits three different patterns: (i) monotonic, or (ii) half-oscillatory, or (iii) highly oscillatory behaviors. These features are understood and confirmed by means of approximate analytical solutions to the evolution equations. Also, the evolution patterns are shown to differ between dipole and quadrudipole pulsar models, depending on the magnetic field strength.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13662-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The “(Brightarrow Kpi ) puzzle”: a new perspective “(Brightarrow Kpi )谜题”：一个新的视角

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2024-12-26 DOI: 10.1140/epjc/s10052-024-13709-2

Adam Szabelski

引用次数: 0

Effect of chiral imbalance on the electrical conductivity of hot and dense quark matter using Green–Kubo method within the 2-flavour gauged NJL model 用Green-Kubo方法在2味量规NJL模型中研究手性不平衡对热稠密夸克物质电导率的影响

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2024-12-26 DOI: 10.1140/epjc/s10052-024-13691-9

Snigdha Ghosh, Nilanjan Chaudhuri, Sourav Sarkar, Pradip Roy

{"title":"Effect of chiral imbalance on the electrical conductivity of hot and dense quark matter using Green–Kubo method within the 2-flavour gauged NJL model","authors":"Snigdha Ghosh, Nilanjan Chaudhuri, Sourav Sarkar, Pradip Roy","doi":"10.1140/epjc/s10052-024-13691-9","DOIUrl":"10.1140/epjc/s10052-024-13691-9","url":null,"abstract":"<div><p>The electrical conductivity of hot and dense quark matter is calculated using the 2-flavour gauged Nambu–Jona–Lasinio (NJL) model in the presence of a chiral imbalance quantified in terms of a chiral chemical potential (CCP). To this end, the in-medium spectral function corresponding to the vector current correlator is evaluated employing the real time formulation of finite temperature field theory. Taking the long wavelength limit of the spectral function we extract the electrical conductivity using the Green–Kubo relation. The thermal widths of the quarks/antiquarks that appear in the expression of electrical conductivity are calculated by considering the <span>(2rightarrow 2)</span> scattering in the NJL model. The scattering amplitudes containing the polarization functions of the mesonic modes in the scalar and pseudoscalar channels are also evaluated by considering finite value of CCP. We find that the ratio of electrical conductivity to temperature has significant dependence on CCP especially in the low temperature region.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13691-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Vortical waves in a quantum fluid with vector, axial, and helical charges. I. Non-dissipative transport 具有矢量、轴向和螺旋电荷的量子流体中的涡旋波。1 .非耗散输运

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2024-12-26 DOI: 10.1140/epjc/s10052-024-13713-6

Sergio Morales-Tejera, Victor E. Ambruş, Maxim N. Chernodub

{"title":"Vortical waves in a quantum fluid with vector, axial, and helical charges. I. Non-dissipative transport","authors":"Sergio Morales-Tejera, Victor E. Ambruş, Maxim N. Chernodub","doi":"10.1140/epjc/s10052-024-13713-6","DOIUrl":"10.1140/epjc/s10052-024-13713-6","url":null,"abstract":"<div><p>Due to the spin-orbit coupling, Dirac fermions, submerged in a thermal bath with finite macroscopic vorticity, exhibit a spin polarisation along the direction parallel to the vorticity vector <span>(varvec{Omega })</span>. Due to the symmetries of the Lagrangian for free massless Dirac particles, there are three independent and classically conserved currents corresponding to the vector, axial, and helical charges. The constitutive relations for the charge currents and the stress-energy tensor at thermal equilibrium, derived in the framework of quantum field theory at finite temperature, reveal vorticity-induced contributions that deviate from the perfect fluid form. In this paper, we consider the mode structure of the corresponding hydrodynamical theory and derive collective excitations associated with coherent fluctuations of all three charges. We show that the chirally imbalanced rotating fluid should possess non-reciprocal gapless waves that propagate with different velocities along and opposite to the vorticity vector. We also uncover a strictly unidirectional mode, which we call the axial vortical wave, propagating in the background of the axial charge density. The emergence of this wave can be traced back to earlier studies of vortical chiral fluids in a hydrodynamic approach. We also point out an unexpected instability in the limit of degenerate matter and discuss possible solutions when helicity and axial charge non-conservation are taken into account.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13713-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Regular black holes from Kiselev anisotropic fluid Kiselev各向异性流体中的规则黑洞

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2024-12-26 DOI: 10.1140/epjc/s10052-024-13664-y

L. C. N. Santos

{"title":"Regular black holes from Kiselev anisotropic fluid","authors":"L. C. N. Santos","doi":"10.1140/epjc/s10052-024-13664-y","DOIUrl":"10.1140/epjc/s10052-024-13664-y","url":null,"abstract":"<div><p>In this paper, we investigate a generalization of Kiselev black holes by introducing a varying equation-of-state parameter for the anisotropic fluid surrounding the black hole. We extend this model by allowing <i>w</i> in the expression <span>(p_t(r)/rho (r) = (3w + 1)/2)</span> to vary as a function of the radial coordinate, and derive new solutions to the Einstein field equations for this configuration. In particular, we study solutions that describe regular black holes. By choosing specific forms of <i>w</i>(<i>r</i>), we obtain regular black hole solutions, and show that the matter surrounding the black hole can satisfy the weak and strong energy conditions under certain values of parameters analyzed. Due to the generality of this treatment, other categories of black holes can be obtained with particular choices of the equation-of-state parameter. Our analysis confirms that the curvature invariants associated with the regular black holes remain finite at the origin, indicating the absence of singularities. We also explore the physical properties of the matter associated with these solutions. Due to its versatility, we suggest the possibility of using this approach as a tool to construct new physical solutions associated with regular black holes or other geometries of interest.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13664-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Exact analytical Taub-NUT like solution in f(T) gravity f(T)重力下的精确解析类Taub-NUT解

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2024-12-25 DOI: 10.1140/epjc/s10052-024-13712-7

Joshua G. Fenwick, Masoud Ghezelbash

引用次数: 0

Thermodynamic of the f(Q) universe f(Q)宇宙的热力学

IF 4.2 2区物理与天体物理

The European Physical Journal C Pub Date : 2024-12-25 DOI: 10.1140/epjc/s10052-024-13711-8

Haomin Rao, Chunhui Liu, Chao-Qiang Geng

引用次数: 0