Journal of Cosmology and Astroparticle Physics最新文献_第2页

Two-component dark matter and low scale thermal Leptogenesis 双组分暗物质与小尺度热致轻生

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2025-09-10 DOI: 10.1088/1475-7516/2025/09/032

Subhaditya Bhattacharya, Devabrat Mahanta, Niloy Mondal and Dipankar Pradhan

引用次数: 0

511 keV galactic photons from a dark matter spike 511 keV星系光子来自暗物质尖峰

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2025-09-10 DOI: 10.1088/1475-7516/2025/09/034

De la Torre Luque, Pedro, Shyam Balaji, Malcolm Fairbairn, Filippo Sala and Joseph Silk

引用次数: 0

Nonseparability of multipartite systems in dilaton black hole 膨胀黑洞中多部系统的不可分性

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2025-09-10 DOI: 10.1088/1475-7516/2025/09/030

Shu-Min Wu, Xiao-Wei Teng, Wen-Mei Li, Yu-Xuan Wang and Jianbo Lu

引用次数: 0

Pressure parametrization of dark energy: first and second-order constraints with latest cosmological data 暗能量的压力参数化：最新宇宙学数据的一阶和二阶约束

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2025-09-10 DOI: 10.1088/1475-7516/2025/09/031

Hanyu Cheng, Eleonora Di Valentino, Luis A. Escamilla, Anjan A. Sen and Luca Visinelli

{"title":"Pressure parametrization of dark energy: first and second-order constraints with latest cosmological data","authors":"Hanyu Cheng, Eleonora Di Valentino, Luis A. Escamilla, Anjan A. Sen and Luca Visinelli","doi":"10.1088/1475-7516/2025/09/031","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/09/031","url":null,"abstract":"We explore an extension of the ΛCDM model in which the pressure p of the dark energy (DE) fluid evolves with the expansion of the Universe, expressed as a function of the scale factor a. The corresponding energy density ρ is derived from the continuity equation, resulting in a dynamical equation-of-state parameter w ≡ p/ρ during the late-time expansion of the Universe. The pressure is modeled using a Taylor expansion around the present epoch (a = 1), introducing deviations from a cosmological constant within the dynamical dark energy (DDE) framework. At first order, a single new parameter Ω1 captures linear deviations, while a second-order parameter, Ω2, accounts for quadratic evolution in the pressure. We constrain the first- and second-order DDE models using multiple observational datasets and compare their performance against ΛCDM and the CPL parameterization. A joint analysis of Planck CMB, DESI, and DESY5 data yields the strongest evidence for DDE, with a 2.7σ deviation in the first-order model and over 4σ in the second-order model — providing strong statistical support for a departure from a cosmological constant. The reconstructed DE evolution in the second-order case reveals a distinctive non-monotonic behavior in both energy density and wDE(a), including clear phantom-crossing phenomena. Notably, the late-time evolution of wDE(a) remains consistent across datasets and shows strong agreement with the CPL parameterization, underscoring the robustness of the pressure-based approach.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"16 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145035464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The role of unitarisation on dark-matter freeze-out via metastable bound states 通过亚稳态束缚态，统一在暗物质冻结中的作用

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2025-09-09 DOI: 10.1088/1475-7516/2025/09/026

Kalliopi Petraki, Anna Socha and Christiana Vasilaki

{"title":"The role of unitarisation on dark-matter freeze-out via metastable bound states","authors":"Kalliopi Petraki, Anna Socha and Christiana Vasilaki","doi":"10.1088/1475-7516/2025/09/026","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/09/026","url":null,"abstract":"In many Abelian and non-Abelian theories, standard calculations of radiative bound-state formation violate partial-wave unitarity — even at arbitrarily small couplings — when capture into excited states is considered. Recent work demonstrated that unitarity can be restored by the proper resummation of squared inelastic processes in the self-energy of the incoming state. We examine how unitarisation affects dark-matter thermal decoupling, given that the formation and decay of metastable dark-matter bound states are critical in determining the relic abundance, especially for multi-TeV dark matter. We consider an Abelian model featuring bound-state formation via emission of a light scalar that carries a conserved charge, whose dynamics also emulates relevant aspects of non-Abelian theories. Incorporating capture into excited states, we show that, without proper treatment, unitarity violation is so severe as to prevent freeze-out. Resumming the squared bound-state formation processes restores unitarity and ensures freeze-out, while capture into excited levels still significantly depletes dark matter. We further discuss the impact of higher partial waves, both within and beyond the present model. Finally, we point out the intriguing possibility of late dark-matter decoupling that can affect structure formation.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"2 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145025340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Spontaneous magnetogenesis at the electroweak phase transition 电弱相变中的自发磁发生

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2025-09-09 DOI: 10.1088/1475-7516/2025/09/023

Valerie Domcke, Yohei Ema and Teerthal Patel

引用次数: 0

Precision calculation of the EFT likelihood with primordial non-Gaussianities 具有原始非高斯性的EFT似然精度计算

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2025-09-09 DOI: 10.1088/1475-7516/2025/09/029

Ji-Yuan Ke, Yun Wang and Ping He

{"title":"Precision calculation of the EFT likelihood with primordial non-Gaussianities","authors":"Ji-Yuan Ke, Yun Wang and Ping He","doi":"10.1088/1475-7516/2025/09/029","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/09/029","url":null,"abstract":"We perform a precision calculation of the effective field theory (EFT) conditional likelihood for large-scale structure (LSS) using the saddle-point expansion method in the presence of primordial non-Gaussianities (PNG). The precision is manifested at two levels: one corresponding to the consideration of higher-order noise terms, and the other to the inclusion of contributions from the saddle-point fluctuations. When computing the latter, we encounter the same issue of the negative modes as in the context of false vacuum decay, which necessitates deforming the original integration contour into a combination of the steepest descent contours to ensure a convergent and real result. We demonstrate through detailed calculations that, upon incorporating leading-order PNG, both types of extensions introduce irreducible field-dependent contributions to the conditional likelihood. This insight motivates the systematic inclusion of additional effective terms within the forward modeling framework. Our work facilitates Bayesian forward modeling under non-Gaussian initial conditions, thereby enabling more stringent constraints on the parameters describing PNG.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"57 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145025405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The role of adiabatic sound speeds in neutron star radial oscillations and stability 绝热声速在中子星径向振荡和稳定性中的作用

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2025-09-09 DOI: 10.1088/1475-7516/2025/09/025

Sayantan Ghosh, Tianqi Zhao, Bharat Kumar and Sailesh Ranjan Mohanty

{"title":"The role of adiabatic sound speeds in neutron star radial oscillations and stability","authors":"Sayantan Ghosh, Tianqi Zhao, Bharat Kumar and Sailesh Ranjan Mohanty","doi":"10.1088/1475-7516/2025/09/025","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/09/025","url":null,"abstract":"We investigate the impact of adiabatic sound speed on the radial oscillations and stability of neutron stars (NSs), using five representative equations of state (EOSs): three hadronic (FSU2R, HPUC, SINPA) and two hybrid (Gibbs 40, KW 55). The adiabatic case, which assumes fixed particle composition during compression, corresponds to slow reaction scenarios and leads to an extension of the stable branch toward smaller radii and higher compactness, even beyond the maximum mass configuration. This extended regime, known as the “slow stable” branch, remains dynamically stable only when reactions are sufficiently slow. To assess stability, we subject the NSs to radial perturbations and examine their fundamental radial (f-mode) oscillations, identifying the transition point where the mode frequency vanishes. The adiabatic sound speed, compared to the equilibrium sound speed, delays the onset of instability, allowing NSs to sustain stability at higher compactness and thus exhibit smaller radii — a more physically realistic outcome for slow reaction rates. Notably, the delays in the onset of instability are more pronounced for hybrid EOSs than for hadronic ones.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"18 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145025339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Entropy production at electroweak bubble walls from scalar field fluctuations 标量场波动下电弱泡壁的熵产生

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2025-09-09 DOI: 10.1088/1475-7516/2025/09/027

M. Eriksson and M. Laine

引用次数: 0

Quasi-Palatini formulation of scalar-tensor gravity 标量张量引力的准palatini公式

IF 6.4 2区物理与天体物理

Journal of Cosmology and Astroparticle Physics Pub Date : 2025-09-09 DOI: 10.1088/1475-7516/2025/09/022

Sotirios Karamitsos

引用次数: 0