Journal of Cosmology and Astroparticle Physics最新文献

{"title":"Gamma-ray constraints on heavy axion-like-particle decays from\u0000 Fermi\u0000 -LAT and H.E.S.S. blazar spectra","authors":"A. Acharyya,F. Aharonian,M. Backes,R. Batzofin,Y. Becherini,S. Bisero,M. Böttcher,C. Boisson,J. Bolmont,F. Brun,C. Burger-Scheidlin,T. Bylund,S. Casanova,D. Cecchin Momesso,M. Cerruti,A. Chen,M. Chernyakova,J.O. Chibueze,O. Chibueze,T. Collins,B. Cornejo,G. Cotter,G. Cozzolongo,J. de Assis Scarp[0009-0004-4411-236X] in,M. de Naurois,E. de Oña Wilhelmi,A. Deka Baruah,A. Dmytriiev,K. Egberts,K. Egg,C. Escañuela Nieves,K. Feijen,M.D. Filipovic,G. Fontaine,S. Funk,S. Gabici,Y.A. Gallant,M. Genaro,P. Geneste,J.F. Glicenstein,P. Goswami,C. Grimaud,L. Heckmann,B. Heß,J.A. Hinton,W. Hofmann,T.L. Holch,M. Holler,M. Jamrozy,F. Jankowsky,I. Jaroschewski,I. Jung-Richardt,D. Kerszberg,B. Khélifi,N. Komin,D. Kostunin,R.G. Lang,S. Lazarević,M. Lemoine-Goumard,J.-P. Lenain,P. Liniewicz,A. Luashvili,J. Mackey,D. Malyshev,D. Malyshev,V. Marandon,M.G.F. Mayer,A. Mehta,M. Meyer,A.M.W. Mitchell,R. Moderski,L. Mohrmann,A. Montanari,E. Moulin,J. Niemiec,L. Olivera-Nieto,M.O. Moghadam,M. Panter,R.D. Parsons,D. Pastuszka Malek,P. Pichard,S. Pita,S. Porras-Bedmar,T. Preis,G. Pühlhofer,M. Punch,A. Quirrenbach,A. Reimer,O. Reimer,H.X. Ren,B. Reville,F. Rieger,G. Roellinghoff,G. Rowell,B. Rudak,K. Sabri,V. Sahakian[0000-0003-1198-0043],A. Santangelo,M. Sasaki,F. Schüssler,J.N.S. Shapopi,W. Si Said,Ł. Stawarz,R. Steenkamp,S. Steinmassl,T. Tanaka,A.M. Taylor,G.L. Taylor,R. Terrier,Y. Tian,T. Unbehaun,C. van Eldik,M. Vecchi,J. Vink,V. Voitsekhovskyi,T. Wach,S.J. Wagner,A. Wierzcholska,M. Zacharias,A. Zech,W. Zhong,The H.E.S.S. collaboration","doi":"10.1088/1475-7516/2026/10/005","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/10/005","url":null,"abstract":"Abstract The propagation of very-high-energy (VHE; E γ ≥ 100 GeV) gamma rays from extragalactic sources is affected by interactions with photons of the extragalactic background light (EBL), resulting in pair production that attenuates the intrinsic gamma-ray flux. This interaction renders the Universe increasingly opaque to VHE photons at high energies and redshifts. New physics scenarios involving axion-like particles (ALPs) could modify this expected optical depth. In particular, ALPs with masses m a ∼ 10 eV can decay into two photons over cosmological timescales, thereby contributing to the diffuse EBL. If such ALPs constitute a significant fraction of the dark matter density, their decay would enhance the EBL intensity and consequently increase the gamma-ray optical depth. In this study, we investigate this scenario using a large sample of gamma-ray spectra observed with the High Energy Stereoscopic System (H.E.S.S.) and the Fermi Large Area Telescope. We model the contribution of decaying ALPs to the EBL and assess their impact on the spectra of blazars across redshifts. By comparing these observations with standard EBL models, we place constraints on the properties of heavy ALPs — specifically their mass and photon coupling — and evaluate their viability as a dark matter candidate capable of modifying the gamma-ray transparency of the Universe. From the combined analysis, and under the assumption that ALPs constitute the entire dark matter density, we derive 95% confidence exclusion limits on the photon-ALP coupling down to m aγ ∼ 7×10 -12 GeV -1 for masses m a ∼ 15 eV. These constraints are competitive with existing astrophysical bounds and provide complementary sensitivity to other techniques, closing a previously unconstrained region of parameter space in the m a ∼ 2.5–20 eV range.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"1 1","pages":"005"},"PeriodicalIF":6.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149089245","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}

{"title":"Natural metric-affine inflation: reloaded","authors":"D. Kraiko,A. Racioppi","doi":"10.1088/1475-7516/2026/10/002","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/10/002","url":null,"abstract":"Abstract We revisit natural inflation within the framework of metric-affine gravity, considering the impact of a periodic non-minimal coupling between the inflaton and the Nieh-Yan term. Such a term, alone, leads to linear inflation predictions in the strong coupling limit and cannot help to rescue the natural inflation scenario. However, once an analogous non-minimal coupling with the Ricci scalar is added, agreement with data can be easily achieved. Remarkably, the scenario remains viable even with a sub-Planckian periodicity scale and relatively small (order of one) non-minimal couplings.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"15 1","pages":"002"},"PeriodicalIF":6.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149089243","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}

{"title":"Constraints on the inflationary vacuum and reheating era from NANOGrav","authors":"Debtosh Chowdhury,Rounak Nath,Sudipta Show","doi":"10.1088/1475-7516/2026/10/009","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/10/009","url":null,"abstract":"Abstract NANOGrav and various pulsar timing array experiments recently reported compelling evidence for a stochastic gravitational wave background (SGWB) signal. In general, such a background can come from several astrophysical and cosmological phenomena. Assuming such SGWB has an inflationary origin, we use latest NANOGrav 15-year dataset to constrain the inflationary parameters e.g., tensor spectral index ( n t ), tensor-to-scalar ratio ( r ), and explore the implications for the reheating phase through constraints on the reheating equation of state ( ω re ) and reheating temperature ( T re ). We find a preference for an extremely blue-tilted tensor spectrum and a non-instantaneous reheating epoch. Despite having no concrete evidence for the nature of the primordial vacua, the computation of gravitational wave (GW) sourced by tensor perturbations assumes the inflationary vacuum to be a Bunch-Davies vacuum. In this work, we examine modifications to the GW spectrum originating from a two-parameter Bogoliubov family of non-Bunch-Davies vacuum. Within this framework, we find that NANOGrav observations favour a subclass of non-Bunch-Davies vacuum, known as the alpha-vacuum. In addition, our analysis demonstrates that the observations strikingly narrow the range of the parameter α that characterizes the vacua. Our analysis indicates that the NANOGrav data can accommodate both matter- and radiation-like reheating scenarios for the standard Bunch-Davies vacuum case. However, within the adopted non-Bunch-Davies vacuum framework, a non-matter-like scenario is preferred, as matter-like reheating requires relatively large values of α , which violate both the upper bound set by NANOGrav observations and the backreaction constraint. Furthermore, we find that a frequency-dependent parametrization of the vacuum parameter α beyond a threshold frequency can yield a minimal solution that alleviates the blue-tilted issue. Finally, we highlight the possibility of testing such frequency dependence of α by probing the GW spectrum through future GW experiments.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"3 1","pages":"009"},"PeriodicalIF":6.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149089244","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}

{"title":"Gravitational wave emission from nonspherical collapse in an early matter-dominated era using N-body simulations","authors":"Albert Escrivà,Tomohiro Harada,Kazunori Kohri,Takahiro Terada,Chul-Moon Yoo","doi":"10.1088/1475-7516/2026/10/017","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/10/017","url":null,"abstract":"Abstract We study the dynamics of the collapse of a nonspherical overdense patch during an early matter-dominated era and the associated production of gravitational waves (GWs) using a semirelativistic N-body framework that we develop. The collapsing patch is initialized through a Zel'dovich deformation of a homogeneous sphere and evolved in an Einstein–de Sitter background, while the emitted signal is computed directly from the numerical quadrupole evolution. We show that a reliable prediction of the signal requires a fully numerical treatment of the nonlinear collapse dynamics. In particular, fitting-based procedures and Zel'dovich-based estimates fail to capture the post-shell-crossing evolution and can over/under-estimate the emitted power of the GWs. After averaging over realizations weighted by the Doroshkevich and BBKS (peak theory) distributions, we find that the two spectra have similar shapes and remain within the same overall order of magnitude at the peak amplitude, although the BBKS result is systematically smaller. The dominant contribution arises from peaks of relatively modest height, around ν≃ 3, while a larger variance significantly enhances the signal. Finally, by varying the horizon mass and reheating temperature, we map the present-day GW spectra to the sensitivity bands of different classes of detectors. In this way, the signal can populate a broad range of frequencies, from pulsar timing arrays to very high-frequency experiments, showing that GWs from nonspherical collapse can provide a probe of the pre-BBN thermal history.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"20 1","pages":"017"},"PeriodicalIF":6.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149089333","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}

{"title":"The muon charge asymmetry and the directional distribution of thunderstorm events observed by the GRAPES-3 muon telescope","authors":"B. Hariharan,S.K. Gupta,Y. Hayashi,P. Jagadeesan,A. Jain,S. Kawakami,H. Kojima,P.K. Mohanty,Y. Muraki,P.K. Nayak,A. Oshima,M. Rameez,K. Ramesh,L.V. Reddy,S. Shibata","doi":"10.1088/1475-7516/2026/10/001","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/10/001","url":null,"abstract":"Abstract The intense electric fields inside thunderstorms can significantly modify the intensity of secondary cosmic ray muons at the ground level, producing measurable variations in their intensity (|ΔI μ | >0.3%). By utilizing the decade-long observations of thunderstorms (April 2011–December 2020) by the GRAPES-3 muon telescope (G3MT), a directional asymmetry in |ΔI μ | is observed, with nearly six times more events being detected from the east than the west directions. Using detailed CORSIKA Monte Carlo simulations, we present that this asymmetry is caused by the variations of the muon charge ratio R μ (N μ + /N μ - ). The anisotropic R μ in turn, is caused by the systematic changes in geomagnetic effects, and subsequent selective filtering of predominantly positively charged primary cosmic rays. As a consequence, the R μ increases systematically from west to east across the G3MT field of view, enhancing the sensitivity of east directions to charged thunderstorms. Independent meteorological validation using ground-based electric field mill data confirms that the thunderstorm trajectories exhibit no eastward preference, ruling out localized storm clustering as a source of the asymmetry. Monte Carlo simulations with constant R μ show that the directional asymmetry disappears, indicating the muon charge imbalance to be the dominant driver of the observed asymmetry. Furthermore, we evaluated the systematic robustness of the framework against variations in hadronic interaction generators, thundercloud configuration, and |ΔI μ |. The dependence of R μ on the hadronic interaction is studied extensively by comparing seven combinations of high-, and low-energy hadronic interaction generators, which show a ≲7% spread in R μ , and ≲14% variation in the derived thunderstorm potentials. These results provide the first quantitative link between the muon charge asymmetry caused by the geomagnetic field, and the directional distribution of thunderstorms, reinforcing the role of muon observations as a probe of gigavolt potentials in atmospheric electrical structures.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"15 1","pages":"001"},"PeriodicalIF":6.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149089334","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}

{"title":"CAMB 2: cosmological power spectra for high-precision surveys","authors":"Antony Lewis","doi":"10.1088/1475-7516/2026/10/013","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/10/013","url":null,"abstract":"Abstract Upcoming cosmic microwave background (CMB) and large-scale-structure surveys require theoretical power spectra with numerical errors well below their observational uncertainties over the scales that carry most of the constraining power. We describe a substantial update to CAMB designed to provide fast, high-precision predictions for two key outputs: the lensed CMB and matter power spectra. The central development is a new treatment of the hyperspherical Bessel functions used for line-of-sight integration in non-flat cosmologies. A leading-order Olver construction maps the curved radial equation onto the flat spherical Bessel equation by matching their actions through the turning point. The resulting approximation is exact in the flat limit, remains smooth through the turning point, and reduces near flatness to a simple rescaling of the flat Bessel argument and amplitude. Occasional evaluations of this map also provide accurate starting values for efficient Numerov propagation between neighbouring source points. We also describe updated integrators, a recalibrated fast recombination model, updated approximations for massive neutrinos, stabilized parameterized post-Friedmann dark-energy evolution, and improvements to CMB lensing accuracy. Numerical convergence is assessed by comparing unboosted default results against more converged calculations across a grid of more than one hundred cosmological configurations. The defaults meet conservative fractional 10 -3 convergence targets over the main lensed-CMB and quasi-linear matter-power ranges relevant for future surveys. Errors measured in typical runs are substantially smaller than this. We also describe the convention dependence of the nominally linear matter power spectrum when a homogeneous calculation attempts to represent the effects of reionization heating. Essentially all of the new algorithms and code were developed with LLMs or AI agents under human supervision.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"4 1","pages":"013"},"PeriodicalIF":6.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149089331","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}

{"title":"Velocity reconstruction from KSZ: measuring\u0000 f\u0000 NL\u0000 with ACT and DESILS","authors":"Selim C. Hotinli,Kendrick M. Smith,Simone Ferraro","doi":"10.1088/1475-7516/2026/10/015","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/10/015","url":null,"abstract":"Abstract The kinetic Sunyaev-Zel'dovich (kSZ) effect offers an indirect way to reconstruct large-scale cosmic velocities, by correlating high-resolution CMB temperature maps with galaxy surveys. In this work, we present the first three-dimensional reconstruction of the large-scale velocity field using a photometric galaxy survey, using data from the DESI Legacy Imaging Surveys (DESILS) and the Atacama Cosmology Telescope (ACT) DR5. We detect an 11.7 σ correlation between our velocity reconstruction and the galaxy field, using only DESILS LRGs in the northern Galactic hemisphere. We find that the overall amplitude of the kSZ-induced correlation is low relative to a halo model prediction ( b v = 0.45 +0.06 -0.05 ), in agreement with previous results which find high feedback and smoothed gas profiles near massive galaxies. We use this measurement to place new constraints on local-type primordial non-Gaussianity (PNG), obtaining f NL = -39 +40 -33 . This represents the most stringent f NL constraint from kSZ velocity-based analyses to date. We validate our findings through extensive null tests, including tests for CMB foregrounds based on comparing 90 and 150 GHz CMB data.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"2019 1","pages":"015"},"PeriodicalIF":6.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149089241","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}

{"title":"Oscillations and parity violation in gravitational wave background from extra tensor modes","authors":"Jaume Garriga,Mohammad Ali Gorji,Fazlollah Hajkarim,Misao Sasaki","doi":"10.1088/1475-7516/2026/10/011","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/10/011","url":null,"abstract":"Abstract Spectator fields which provide additional tensor degrees of freedom, on top of the standard metric tensor perturbations, can produce significant amounts of gravitational waves (GWs). Employing the effective field theory approach for spin-2 fields, we identify a characteristic prediction of this class of scenarios: whenever the spin-2 sector undergoes a localized non-adiabatic evolution during inflation, the linear mixing between the metric and extra tensor modes transmits this feature to the GW spectrum as oscillations in scale. The leading oscillation period is determined analytically by the time at which the localized feature occurs and by the propagation speed of the extra tensor mode outside the feature. The same coupling, when sufficiently strong, also drives an in-time oscillation of the superhorizon modes that is reminiscent of neutrino flavor oscillations. Moreover, parity-violating operators in the spin-2 EFT can imprint chiral signatures on the resulting GW background. Such chirality is an important possible signature for features in the non-minimal kinetic coupling, and becomes closely tied to large observable enhancement for features in the sound speed of the extra tensor mode. We consider a concrete scenario in which the spin-2 field generates observable chiral GWs with characteristic oscillatory patterns. These results identify robust signatures that can be probed with future GW detectors, while the exact amplitude, peak position, and parameter values remain model dependent.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"7 1","pages":"011"},"PeriodicalIF":6.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149089246","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}

{"title":"Phenomenology of vector dark matter produced by a first order phase transition","authors":"M. Fairbairn,W.S.A. Shellard","doi":"10.1088/1475-7516/2026/10/010","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/10/010","url":null,"abstract":"Abstract Both scalar and vector dark matter can be produced during a cosmological first order phase transition if the dark matter is coupled to the field undergoing the transition. Both kinds of particle are also produced by the plasma through the normal freeze out scenario. For different dark matter masses, we identify the regions of parameter space where there are significant deviations from the normal freeze out scenario and discover there are some rather general predictions. For dark matter particles in the traditional thermal relic GeV-TeV window, dark sector phase transitions around a GeV affect scalar dark matter and dark sector phase transitions around 10 MeV affect vector dark matter abundances (and therefore should take place in a dark sector). When the phase transitions are in the interesting temperature range, the normal range of dark matter masses are different to those predicted by thermal freeze out. We calculate the expected gravitational wave signal of these phase transitions.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"1 1","pages":"010"},"PeriodicalIF":6.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149089332","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}

{"title":"Probing dynamical dark energy with late-time data: Evidence, tensions, and the limits of the w 0 wa CDM framework","authors":"Tengpeng Xu, Suresh Kumar, Yun Chen, Abraão J.S. Capistrano and Özgür Akarsu","doi":"10.1088/1475-7516/2026/08/004","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/08/004","url":null,"abstract":"We test the dynamical dark-energy w0waCDM (CPL) framework against ΛCDM using CMB anisotropies and lensing together with DESI DR2, SDSS-IV, transverse/angular BAO (BAOtr), and Cepheid-calibrated PantheonPlus SN Ia data. CPL inferences are strongly dataset-dependent. CMB data alone leave a broad geometric degeneracy, while DESI DR2 BAO pulls the reconstruction toward weak present-day acceleration. In contrast, CMB combined with PP&SH0ES and BAOtr favors a moderately accelerating expansion and substantially reduces the Hubble tension. The origin of this behavior can be traced to low-redshift distance information: BAOtr and DESI/SDSS prefer different BAO distance ratios at z ≲ 0.5, which drives divergent CPL expansion histories. We quantify this mismatch directly at the data level by comparing angular BAO scales, including the common z = 0.510 point and a conservative local interpolation of BAOtr with no extrapolation. As expected within CPL, where pre-recombination physics is fixed, rd remains nearly unchanged, so shifts in H0 are absorbed by late-time expansion freedom rather than by a change in the sound horizon. Bayesian evidence is likewise contingent on the low-redshift data: it favors CPL mainly when PP&SH0ES and/or BAOtr are included, is inconclusive for CMB-only and CMB+DESI, and moderately favors ΛCDM for CMB+SDSS. These results show that apparent support for CPL and its ability to ease the Hubble tension are not universal, motivating more flexible late-time models and closer scrutiny of BAO systematics.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"157 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148675071","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}