D. Forero-Sánchez, M. Rashkovetskyi, O. Alves, A. de Mattia, N. Padmanabhan, H. Seo, S. Nadathur, A.J. Ross, H. Gil-Marín, P. Zarrouk, J. Yu, Z. Ding, U. Andrade, X. Chen, C. Garcia-Quintero, J. Mena-Fernández, S. Ahlen, D. Bianchi, D. Brooks, E. Burtin, E. Chaussidon, T. Claybaugh, S. Cole, A. de la Macorra, M. Enriquez-Vargas, E. Gaztañaga, G. Gutierrez, K. Honscheid, C. Howlett, T. Kisner, M. Landriau, L. Le Guillou, M.E. Levi, R. Miquel, J. Moustakas, N. Palanque-Delabrouille, W.J. Percival, I. Pérez-Ràfols, G. Rossi, E. Sanchez, D. Schlegel, M. Schubnell, D. Sprayberry, G. Tarlé, M. Vargas-Magaña, B.A. Weaver and H. Zou
{"title":"Analytical and EZmock covariance validation for the DESI 2024 results","authors":"D. Forero-Sánchez, M. Rashkovetskyi, O. Alves, A. de Mattia, N. Padmanabhan, H. Seo, S. Nadathur, A.J. Ross, H. Gil-Marín, P. Zarrouk, J. Yu, Z. Ding, U. Andrade, X. Chen, C. Garcia-Quintero, J. Mena-Fernández, S. Ahlen, D. Bianchi, D. Brooks, E. Burtin, E. Chaussidon, T. Claybaugh, S. Cole, A. de la Macorra, M. Enriquez-Vargas, E. Gaztañaga, G. Gutierrez, K. Honscheid, C. Howlett, T. Kisner, M. Landriau, L. Le Guillou, M.E. Levi, R. Miquel, J. Moustakas, N. Palanque-Delabrouille, W.J. Percival, I. Pérez-Ràfols, G. Rossi, E. Sanchez, D. Schlegel, M. Schubnell, D. Sprayberry, G. Tarlé, M. Vargas-Magaña, B.A. Weaver and H. Zou","doi":"10.1088/1475-7516/2025/04/055","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/055","url":null,"abstract":"The estimation of uncertainties in cosmological parameters is an important challenge in Large-Scale-Structure (LSS) analyses. For standard analyses such as Baryon Acoustic Oscillations (BAO) and Full-Shape two approaches are usually considered. First: analytical estimates of the covariance matrix use Gaussian approximations and (nonlinear) clustering measurements to estimate the matrix, which allows a relatively fast and computationally cheap way to generate matrices that adapt to an arbitrary clustering measurement. On the other hand, sample covariances are an empirical estimate of the matrix based on an ensemble of clustering measurements from fast and approximate simulations. While more computationally expensive due to the large amount of simulations and volume required, these allow us to take into account systematics that are impossible to model analytically. In this work we compare these two approaches in order to enable DESI's key analyses. We find that the configuration space analytical estimate performs satisfactorily in BAO analyses and its flexibility in terms of input clustering makes it the fiducial choice for DESI's 2024 BAO analysis. On the contrary, the analytical computation of the covariance matrix in Fourier space does not reproduce the expected measurements in terms of Full-Shape analyses, which motivates the use of a corrected mock covariance for DESI's 2024 Full Shape analysis.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"99 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847055","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}
Cristina Benso, Thomas Schwetz and Drona Vatsyayan
{"title":"Large neutrino mass in cosmology and keV sterile neutrino dark matter from a dark sector","authors":"Cristina Benso, Thomas Schwetz and Drona Vatsyayan","doi":"10.1088/1475-7516/2025/04/054","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/054","url":null,"abstract":"We consider an extended seesaw model which generates active neutrino masses via the usual type-I seesaw and leads to a large number of massless fermions as well as a sterile neutrino dark matter (DM) candidate in the 𝒪(10–100) keV mass range. The dark sector comes into thermal equilibrium with Standard Model neutrinos after neutrino decoupling and before recombination via a U(1) gauge interaction in the dark sector. This suppresses the abundance of active neutrinos and therefore reconciles sizeable neutrino masses with cosmology. The DM abundance is determined by freeze-out in the dark sector, which allows avoiding bounds from X-ray searches. Our scenario predicts a slight increase in the effective number of neutrino species Neff at recombination, potentially detectable by future CMB missions.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"64 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847054","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":"Cosmic (super)strings with a time-varying tension","authors":"Filippo Revello and Gonzalo Villa","doi":"10.1088/1475-7516/2025/04/049","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/049","url":null,"abstract":"Cosmic (super)strings offer promising ways to test ideas about the early universe and physics at high energies. While in field theory constructions their tension is usually assumed to be constant (or at most slowly-varying), this is often not the case in the context of String Theory. Indeed, the tensions of both fundamental and field theory strings within a string compactification depend on the expectation values of the moduli, which in turn can vary with time. We discuss how the evolution of a cosmic string network changes with a time-dependent tension, both for long-strings and closed loops, by providing an appropriate generalisation of the Velocity One Scale (VOS) model and its implications. The resulting phenomenology is very rich, exhibiting novel features such as growing loops, percolation and a radiation-like behaviour of the long string network. We conclude with a few remarks on the impact for gravitational wave emission.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"9 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847268","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}
Mark Hindmarsh, Deanna C. Hooper, Tiina Minkkinen and David J. Weir
{"title":"Recovering a phase transition signal in simulated LISA data with a modulated galactic foreground","authors":"Mark Hindmarsh, Deanna C. Hooper, Tiina Minkkinen and David J. Weir","doi":"10.1088/1475-7516/2025/04/052","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/052","url":null,"abstract":"Stochastic backgrounds of gravitational waves from primordial first-order phase transitions are a key probe of physics beyond the Standard Model. They represent one of the best prospects for observing or constraining new physics with the LISA gravitational wave observatory. However, the large foreground population of galactic binaries in the same frequency range represents a challenge, and will hinder the recovery of a stochastic background. To test the recoverability of a stochastic gravitational wave background, we use the LISA Simulation Suite to generate data incorporating both a stochastic background and an annually modulated foreground modelling the galactic binary population, and the Bayesian analysis code Cobaya to attempt to recover the model parameters. By applying the Deviance Information Criterion to compare models with and without a stochastic background we place bounds on the detectability of gravitational waves from first-order phase transitions. By further comparing models with and without the annual modulation, we show that exploiting the modulation improves the goodness-of-fit and gives a modest improvement to the bounds on detectable models.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"10 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847052","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}
Jörn Kersten, Seong Chan Park, Yeji Park, Juhoon Son and Liliana Velasco-Sevilla
{"title":"Gravitational waves from a first-order phase transition of the inflaton","authors":"Jörn Kersten, Seong Chan Park, Yeji Park, Juhoon Son and Liliana Velasco-Sevilla","doi":"10.1088/1475-7516/2025/04/053","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/053","url":null,"abstract":"We explore the production of gravitational waves resulting from a first-order phase transition (FOPT) in a non-minimally coupled `Dark Higgs Inflation' model. Utilizing a dark sector scalar field as the inflaton, we demonstrate how inflationary dynamics set the stage for observable FOPT. These transitions, influenced by thermal and quantum effects, generate gravitational wave spectra potentially detectable by observatories such as LISA, DECIGO, the Cosmic Explorer and the Einstein Telescope. Our study highlights the inflaton's dual role in cosmic inflation and early Universe phase transitions, presenting a unified framework to probe physics beyond the Standard Model through gravitational wave astronomy.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"30 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847053","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":"Itô, Stratonovich, and zoom-in schemes in stochastic inflation","authors":"Eemeli Tomberg","doi":"10.1088/1475-7516/2025/04/035","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/035","url":null,"abstract":"The Itô and Stratonovich approaches are two ways to integrate stochastic differential equations. Detailed knowledge of the origin of the stochastic noise is needed to determine which approach suits a particular problem. I discuss this topic pedagogically in stochastic inflation, where the noise arises from a changing comoving coarse-graining scale or, equivalently, from `zooming in' into inflating space. I introduce a zoom-in scheme where deterministic evolution alternates with instantaneous zoom-in steps. I show that this alternating zoom-in scheme is equivalent to the Itô approach in the Markovian limit, while the Stratonovich approach doesn't have a similar interpretation. In the full non-Markovian setup, the difference vanishes. The framework of zoom-in schemes clarifies the relationship between computations in stochastic inflation, linear perturbation theory, and the classical ΔN formalism. It informs the numerical implementation of stochastic inflation and is a building block for a first-principles derivation of the stochastic equations.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"74 3 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841077","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":"Constraining symmetron fields with a levitated optomechanical system","authors":"Jiawei Li and Ka-Di Zhu","doi":"10.1088/1475-7516/2025/04/036","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/036","url":null,"abstract":"The symmetron, one of the light scalar fields introduced by dark energy theories, is thought to modify the gravitational force when it couples to matter. However, detecting the symmetron field is challenging due to its screening behavior in the high-density environment of traditional measurements. In this paper, we propose a scheme to set constraints on the parameters of the symmetron with a levitated optomechanical system, in which a nanosphere serves as a testing mass coupled to an optical cavity. By measuring the frequency shift of the probe transmission spectrum, we can establish constraints for our scheme by calculating the symmetron-induced influence. These refined constraints improve by 1 to 3 orders of magnitude compared to current force-based detection methods, which offer new opportunities for the dark energy detection.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"97 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841078","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 waves from metastable cosmic strings in the delayed scaling scenario","authors":"Yifan Hu and Kohei Kamada","doi":"10.1088/1475-7516/2025/04/044","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/044","url":null,"abstract":"Recent observations by pulsar timing arrays (PTAs) such as NANOGrav, EPTA, InPTA, PPTA, and CPTA suggest the presence of nanohertz stochastic gravitational wave background (GWB). While such signals could be explained by gravitational waves from a network of metastable cosmic strings (CSs), standard scenarios involving the Kibble-Zurek mechanism triggered by a thermal potential face significant challenges. Specifically, these scenarios predict a GWB spectrum inconsistent with the non-detection at higher frequencies by LIGO-Virgo-KAGRA (LVK) for CSs with relatively large string tension. It is also difficult to prevent the monopole forming phase transition just before the CS forming symmetry breaking, which spoils the CS network formation. In contrast, a delayed scaling scenario, where the CSs start to emit GWs at a later time due to the dilution during inflation, alleviates these issues. This scenario allows for a larger string tension while monopoles are sufficiently diluted such that the CS network safely forms. In this study, we clarify the spectrum of stochastic GWB from metastable CSs in the delayed scaling scenario, consistent with the PTA observations while satisfying the LVK constraints. Furthermore, we explore its potential signatures at frequencies accessible to other detectors such as LVK as well as LISA, Taiji, and TianQin or DECIGO and BBO. We also discuss the implications on inflation and underlying UV theories, such as the grand unified theories.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"50 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841309","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}
Nastassia Grimm, Martin Pijnenburg, Giulia Cusin and Camille Bonvin
{"title":"The impact of large-scale galaxy clustering on the variance of the Hellings-Downs correlation: numerical results","authors":"Nastassia Grimm, Martin Pijnenburg, Giulia Cusin and Camille Bonvin","doi":"10.1088/1475-7516/2025/04/047","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/047","url":null,"abstract":"Pulsar timing array experiments have recently found evidence for a stochastic gravitational wave (GW) background, which induces correlations among pulsar timing residuals described by the Hellings and Downs (HD) curve. Standard calculations of the HD correlation and its variance assume an isotropic background. However, for a background of astrophysical origin, we expect a higher GW spectral density in directions with higher galaxy number densities. In a companion paper, we have developed a theoretical formalism to account for the anisotropies arising from large-scale galaxy clustering, leading to a new contribution to the variance of the HD correlation. In this subsequent work, we provide numerical results for this novel effect. We consider a GW background resulting from mergers of supermassive black hole binaries, and relate the merger number density to the overdensity of galaxies. We find that anisotropies due to large-scale galaxy clustering lead to a standard deviation of the HD correlation at most at percent level, remaining well below the standard contributions to the HD variance. Hence, this kind of anisotropies in the GW source distribution does not represent a substantial contamination to the correlations of timing residuals in present and future PTA surveys. Suitable statistical methods to extract the galaxy clustering signal from PTA data will be investigated in the future.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"74 3 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841313","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}
Julien Dörner, Leonel Morejon, Karl-Heinz Kampert and Julia Becker Tjus
{"title":"Uncertainties in astrophysical gamma-ray and neutrino fluxes from proton-proton cross-sections in the GeV to PeV range","authors":"Julien Dörner, Leonel Morejon, Karl-Heinz Kampert and Julia Becker Tjus","doi":"10.1088/1475-7516/2025/04/043","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/04/043","url":null,"abstract":"The identification of Cosmic Ray (CR) sources represents one of the biggest and long-standing questions in astrophysics. Direct measurements of cosmic rays cannot provide directional information due to their deflection in (extra)galactic magnetic fields. Cosmic-ray interactions at the sources lead to the production of high-energy gamma rays and neutrinos, which, combined in the multimessenger picture, are the key to identifying the origins of CRs and estimating transport properties. While gamma-ray observations alone raise the question of whether their origin is hadronic or leptonic, the observation of high-energy neutrino emission directly points to the presence of CR hadrons. To identify the emission signatures from acceleration and transport effects a proper modeling of those interactions in a transport framework is needed. Significant work has been done to tune the production cross sections to accelerator data and different models exist that put the exact evolution of the Monte-Carlo generated showers into a statistical approach of a probabilistic description of the production of the final states of the showers relevant for astrophysical observations. In this work, we present the implementation of different hadronic interaction (HI) models into the publicly available transport code CRPropa. We apply different descriptions of the HI, trained on observational data in different energy regimes to a nearby, giant molecular cloud and the Galactic diffuse emission. In this case, the resulting gamma-ray and neutrinos fluxes can differ by a factor ∼ 2 dependent on the choice of the HI model.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"101 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841308","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}
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