Pub Date : 2026-03-11DOI: 10.1088/1475-7516/2026/03/034
Garance Lankester-Broche and Josef Pradler
We derive the energy-differential cross section and energy loss rate for dissipative self-interacting dark matter (dSIDM) models within the Born regime using perturbative quantum field theory. Six dissipative scenarios are considered, incorporating the emission of particles that may be either massless or possess a kinematically allowed light mass. Both short-range and long-range force-mediated dSIDM interactions are examined. In the non-relativistic regime, we obtain closed-form expressions of the energy-differential cross sections by a controlled expansion in the initial relative dark matter velocity. Up to trivial factors, the leading-order squared emission amplitude is model-independent for massless emissions. Model dependence arises for massive particle emission and at the next-to-leading order. The latter reduces to three distinct cases. The derived analytical expressions exhibit excellent agreement with numerical computations, providing simple, ready-to-use formulas. Furthermore, we analyze the behavior of these processes in the soft emission limit. Our results show that additional corrections are necessary when applying factorization at the next-to-leading order in a velocity expansion to ensure consistency between the soft energy-differential cross section and the full counterparts across a broad energy range. Finally, we investigate the regime of perturbative validity in terms of the model parameters, identifying the conditions under which our results are applicable.
{"title":"Towards a theory of dissipative Dark Matter. Part I. The Born limit","authors":"Garance Lankester-Broche and Josef Pradler","doi":"10.1088/1475-7516/2026/03/034","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/03/034","url":null,"abstract":"We derive the energy-differential cross section and energy loss rate for dissipative self-interacting dark matter (dSIDM) models within the Born regime using perturbative quantum field theory. Six dissipative scenarios are considered, incorporating the emission of particles that may be either massless or possess a kinematically allowed light mass. Both short-range and long-range force-mediated dSIDM interactions are examined. In the non-relativistic regime, we obtain closed-form expressions of the energy-differential cross sections by a controlled expansion in the initial relative dark matter velocity. Up to trivial factors, the leading-order squared emission amplitude is model-independent for massless emissions. Model dependence arises for massive particle emission and at the next-to-leading order. The latter reduces to three distinct cases. The derived analytical expressions exhibit excellent agreement with numerical computations, providing simple, ready-to-use formulas. Furthermore, we analyze the behavior of these processes in the soft emission limit. Our results show that additional corrections are necessary when applying factorization at the next-to-leading order in a velocity expansion to ensure consistency between the soft energy-differential cross section and the full counterparts across a broad energy range. Finally, we investigate the regime of perturbative validity in terms of the model parameters, identifying the conditions under which our results are applicable.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"67 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147383714","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}
Pub Date : 2026-03-11DOI: 10.1088/1475-7516/2026/03/033
O. Adriani, A. Albert, A.R. Alhebsi, S. Alshalloudi, S. Alves Garre, A. Ambrosone, F. Ameli, M. Andre, L. Aphecetche, M. Ardid, S. Ardid, J. Aublin, F. Badaracco, L. Bailly-Salins, B. Baret, A. Bariego-Quintana, M. Barnard, Y. Becherini, M. Bendahman, F. Benfenati Gualandi, M. Benhassi, D.M. Benoit, Z. Beňušová, E. Berbee, C. van Bergen, E. Berti, V. Bertin, P. Betti, S. Biagi, M. Boettcher, D. Bonanno, M. Bondì, S. Bottai, A.B. Bouasla, J. Boumaaza, M. Bouta, M. Bouwhuis, C. Bozza, R.M. Bozza, H. Brânzaş, F. Bretaudeau, M. Breuhaus, R. Bruijn, J. Brunner, R. Bruno, E. Buis, R. Buompane, I. Burriel, J. Busto, B. Caiffi, D. Calvo, A. Capone, F. Carenini, V. Carretero, T. Cartraud, P. Castaldi, V. Cecchini, S. Celli, L. Cerisy, M. Chabab, N. Chau, A. Chen, S. Cherubini, T. Chiarusi, W. Chung, M. Circella, R. Clark, R. Cocimano, J.A.B. Coelho, A. Coleiro, A. Condorelli, R. Coniglione, P. Coyle, A. Creusot, G. Cuttone, R. Dallier, A. De Benedittis, X. de La Bernardie, G. De Wasse..
The KM3NeT collaboration has reported the detection of the highest energy neutrino event observed to date. The energy of the event is of the order of 220 PeV hinting towards a neutrino flux at the highest energies. In this article, the potential blazar origin for this event is explored. The publicly available Astro-Multimessenger Modeling software is used to model the blazar gamma-ray and neutrino fluxes. It is concluded that a population of blazars could produce the diffuse flux compatible with the observation of the ultra-high energy event detected by the KM3NeT/ARCA detector. At the same time, the gamma-ray flux produced by such a population of blazars is consistent with the diffuse gamma-ray flux measured by the Fermi Large Area Telescope.
{"title":"Blazars as a potential origin of the KM3-230213A event","authors":"O. Adriani, A. Albert, A.R. Alhebsi, S. Alshalloudi, S. Alves Garre, A. Ambrosone, F. Ameli, M. Andre, L. Aphecetche, M. Ardid, S. Ardid, J. Aublin, F. Badaracco, L. Bailly-Salins, B. Baret, A. Bariego-Quintana, M. Barnard, Y. Becherini, M. Bendahman, F. Benfenati Gualandi, M. Benhassi, D.M. Benoit, Z. Beňušová, E. Berbee, C. van Bergen, E. Berti, V. Bertin, P. Betti, S. Biagi, M. Boettcher, D. Bonanno, M. Bondì, S. Bottai, A.B. Bouasla, J. Boumaaza, M. Bouta, M. Bouwhuis, C. Bozza, R.M. Bozza, H. Brânzaş, F. Bretaudeau, M. Breuhaus, R. Bruijn, J. Brunner, R. Bruno, E. Buis, R. Buompane, I. Burriel, J. Busto, B. Caiffi, D. Calvo, A. Capone, F. Carenini, V. Carretero, T. Cartraud, P. Castaldi, V. Cecchini, S. Celli, L. Cerisy, M. Chabab, N. Chau, A. Chen, S. Cherubini, T. Chiarusi, W. Chung, M. Circella, R. Clark, R. Cocimano, J.A.B. Coelho, A. Coleiro, A. Condorelli, R. Coniglione, P. Coyle, A. Creusot, G. Cuttone, R. Dallier, A. De Benedittis, X. de La Bernardie, G. De Wasse..","doi":"10.1088/1475-7516/2026/03/033","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/03/033","url":null,"abstract":"The KM3NeT collaboration has reported the detection of the highest energy neutrino event observed to date. The energy of the event is of the order of 220 PeV hinting towards a neutrino flux at the highest energies. In this article, the potential blazar origin for this event is explored. The publicly available Astro-Multimessenger Modeling software is used to model the blazar gamma-ray and neutrino fluxes. It is concluded that a population of blazars could produce the diffuse flux compatible with the observation of the ultra-high energy event detected by the KM3NeT/ARCA detector. At the same time, the gamma-ray flux produced by such a population of blazars is consistent with the diffuse gamma-ray flux measured by the Fermi Large Area Telescope.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"45 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147383352","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}
Pub Date : 2026-03-11DOI: 10.1088/1475-7516/2026/03/039
Maverick S.H. Oh, Anna Nierenberg, Daniel Gilman and Simon Birrer
Flux-ratio anomalies in quadruply imaged quasars provide a sensitive probe of low-mass dark-matter haloes, but their interpretation requires a robust smooth lens model. Massive early-type galaxies exhibit small deviations from perfect ellipticity, described by m = 3 and m = 4 multipoles. We construct a five-dimensional joint population prior for these multipole amplitudes and orientations, conditioned on the axis ratio q and calibrated on 840 SDSS E/S0 galaxies. We then test its impact on mock lenses resembling HST-quality data under two multipole strength scenarios and four inference setups: point sources only with flat and joint multipole priors and point sources with arcs with flat and joint multipole priors. When only quasar point images are available, the joint prior reduces degeneracies and tightens the 68% credible intervals of a3/a and a4/a by factors of ∼9 and ∼6, and improves the predicted flux — ratio precision by factors of ∼2–6. Adding extended arcs yields a much larger gain — uncertainties shrink by ∼20× for flat priors and ∼8× for joint priors — while there is additional boost from the joint multipole prior (∼10%). The trends are consistent across both mild and strong multipole scenarios. These results show that arcs dominate the constraining power when available, but that a realistic joint multipole prior remains crucial for lenses without arcs. This regime will be common in upcoming wide-field surveys such as the Nancy Grace Roman Space Telescope and Rubin LSST, which will discover ≳ 105 new strong lenses, many lacking resolved arcs. Our framework provides a scalable path toward accurate macromodels for these survey discoveries.
{"title":"Joint semi-analytic multipole priors from galaxy isophotes and constraints from lensed arcs","authors":"Maverick S.H. Oh, Anna Nierenberg, Daniel Gilman and Simon Birrer","doi":"10.1088/1475-7516/2026/03/039","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/03/039","url":null,"abstract":"Flux-ratio anomalies in quadruply imaged quasars provide a sensitive probe of low-mass dark-matter haloes, but their interpretation requires a robust smooth lens model. Massive early-type galaxies exhibit small deviations from perfect ellipticity, described by m = 3 and m = 4 multipoles. We construct a five-dimensional joint population prior for these multipole amplitudes and orientations, conditioned on the axis ratio q and calibrated on 840 SDSS E/S0 galaxies. We then test its impact on mock lenses resembling HST-quality data under two multipole strength scenarios and four inference setups: point sources only with flat and joint multipole priors and point sources with arcs with flat and joint multipole priors. When only quasar point images are available, the joint prior reduces degeneracies and tightens the 68% credible intervals of a3/a and a4/a by factors of ∼9 and ∼6, and improves the predicted flux — ratio precision by factors of ∼2–6. Adding extended arcs yields a much larger gain — uncertainties shrink by ∼20× for flat priors and ∼8× for joint priors — while there is additional boost from the joint multipole prior (∼10%). The trends are consistent across both mild and strong multipole scenarios. These results show that arcs dominate the constraining power when available, but that a realistic joint multipole prior remains crucial for lenses without arcs. This regime will be common in upcoming wide-field surveys such as the Nancy Grace Roman Space Telescope and Rubin LSST, which will discover ≳ 105 new strong lenses, many lacking resolved arcs. Our framework provides a scalable path toward accurate macromodels for these survey discoveries.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"107 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147383360","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}
Pub Date : 2026-03-11DOI: 10.1088/1475-7516/2026/03/037
Jordan Krywonos, Yurii Kvasiuk, Matthew C. Johnson and Moritz Münchmeyer
For many analyses in cosmology it is necessary to reconstruct the likely distribution of unobserved fields, such as dark matter or non-luminous baryons, from observed luminous tracers. The dominant approach in cosmology has been to use the so-called halo model, which assumes radially symmetric profiles centered around luminous tracers such as galaxies. More recently, field-level machine learning methods have been proposed that can learn to estimate the unobserved field after being trained on simulations. However, it is unclear whether machine learning methods indeed significantly improve over linear methods or the halo model. In this paper we make a systematic comparison of different approaches to reconstruct dark matter and non-luminous baryons, from galaxy data using the CAMELS simulations. These simulations are in a 25 Mpc/h box, allowing us to compare performance on the mildly non-linear scales (k ∼ 0.4 h/Mpc) down to the size of individual halos. We find the best results using a combined GNN-CNN approach. We also provide a general analysis and visualization of the relationship of matter, non-luminous baryons, halos, and galaxies in these simulations to interpret our results.
{"title":"Reconstruction of dark matter and baryon density from galaxies: a comparison of linear, halo model and machine learning-based methods","authors":"Jordan Krywonos, Yurii Kvasiuk, Matthew C. Johnson and Moritz Münchmeyer","doi":"10.1088/1475-7516/2026/03/037","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/03/037","url":null,"abstract":"For many analyses in cosmology it is necessary to reconstruct the likely distribution of unobserved fields, such as dark matter or non-luminous baryons, from observed luminous tracers. The dominant approach in cosmology has been to use the so-called halo model, which assumes radially symmetric profiles centered around luminous tracers such as galaxies. More recently, field-level machine learning methods have been proposed that can learn to estimate the unobserved field after being trained on simulations. However, it is unclear whether machine learning methods indeed significantly improve over linear methods or the halo model. In this paper we make a systematic comparison of different approaches to reconstruct dark matter and non-luminous baryons, from galaxy data using the CAMELS simulations. These simulations are in a 25 Mpc/h box, allowing us to compare performance on the mildly non-linear scales (k ∼ 0.4 h/Mpc) down to the size of individual halos. We find the best results using a combined GNN-CNN approach. We also provide a general analysis and visualization of the relationship of matter, non-luminous baryons, halos, and galaxies in these simulations to interpret our results.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"6 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147383355","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}
Pub Date : 2026-03-11DOI: 10.1088/1475-7516/2026/03/036
Nihar Dalal, Chun-Hao To, Chris Hirata, Tae Hyeon-Shin, Matt Hilton, Shivam Pandey and J. Richard Bond
The next generation of cosmology surveys will probe the matter distribution of the universe to unparalleled precision. To match this level of precision in cosmological parameter estimation, we need to use information at small scales of ∼ 1 Mpc, which requires an accurate model of baryonic feedback. In this paper, we employ the Dark Matter + Baryon (DMB) model, a flexible halo model that is well-fit to various hydrodynamical simulations, to extract information on baryonic feedback from galaxy cluster observables. Using a sample of thermal Sunyaev-Zeldovich (tSZ) selected galaxy clusters from the Atacama Cosmology Telescope (ACT) — with masses calibrated via weak lensing from the Dark Energy Survey (DES) — we develop a robust end-to-end pipeline that directly models the calibrated observables. Our analysis demonstrates that the tSZ Y-M relation can constrain several DMB model parameters, providing key insights into baryonic feedback effects on cosmic shear at the several percent level. We find a preference for intermediate to strong levels of feedback, which is both consistent with several hydrodynamic simulations and competitive with similar analyses performed on complementary probes. Finally, we discuss the implications of our results in the context of current and upcoming cosmic shear surveys.
{"title":"Deciphering baryonic feedback from ACT tSZ galaxy clusters","authors":"Nihar Dalal, Chun-Hao To, Chris Hirata, Tae Hyeon-Shin, Matt Hilton, Shivam Pandey and J. Richard Bond","doi":"10.1088/1475-7516/2026/03/036","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/03/036","url":null,"abstract":"The next generation of cosmology surveys will probe the matter distribution of the universe to unparalleled precision. To match this level of precision in cosmological parameter estimation, we need to use information at small scales of ∼ 1 Mpc, which requires an accurate model of baryonic feedback. In this paper, we employ the Dark Matter + Baryon (DMB) model, a flexible halo model that is well-fit to various hydrodynamical simulations, to extract information on baryonic feedback from galaxy cluster observables. Using a sample of thermal Sunyaev-Zeldovich (tSZ) selected galaxy clusters from the Atacama Cosmology Telescope (ACT) — with masses calibrated via weak lensing from the Dark Energy Survey (DES) — we develop a robust end-to-end pipeline that directly models the calibrated observables. Our analysis demonstrates that the tSZ Y-M relation can constrain several DMB model parameters, providing key insights into baryonic feedback effects on cosmic shear at the several percent level. We find a preference for intermediate to strong levels of feedback, which is both consistent with several hydrodynamic simulations and competitive with similar analyses performed on complementary probes. Finally, we discuss the implications of our results in the context of current and upcoming cosmic shear surveys.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"188 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147383354","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}
Pub Date : 2026-03-09DOI: 10.1088/1475-7516/2026/03/026
Anton Stall and Philipp Mertsch
Galactic diffuse emissions in gamma rays and neutrinos arise from interactions of cosmic rays with the interstellar medium and probe the cosmic-ray intensity away from the Solar system. Model predictions for those are influenced by the properties of cosmic-ray sources, and understanding the impact of cosmic-ray sources on Galactic diffuse emissions is key for interpreting measurements by LHAASO, Tibet AS-gamma, IceCube, and the upcoming SWGO. We consider supernova remnants as prototypical cosmic-ray sources and study the impact of their discreteness on the Galactic diffuse emissions in different source injection and near-source transport models in a stochastic Monte Carlo study. Three lessons exemplify the results of our simulations: First, the distributions of Galactic diffuse emission intensities can be described by a mixture model of stable laws and Gaussian distributions. Second, the maximal deviations caused by discrete sources across the sky depend on energy, reaching typically tens of percent in burst-like and energy-dependent escape scenarios but order unity or larger in a time-dependent diffusion scenario. Third, the additional model uncertainty from source stochasticity is subdominant in burst-like and energy-dependent escape scenarios, but becomes sizeable above some tens of TeV in the time-dependent diffusion scenario, where it can help reconcile model predictions with LHAASO measurements. With increased spatial resolution, especially at energies beyond tens of TeV, measurements of Galactic diffuse emissions can be expected to constrain source models and locate cosmic ray sources.
{"title":"Stochastic modelling of cosmic-ray sources for Galactic diffuse emissions","authors":"Anton Stall and Philipp Mertsch","doi":"10.1088/1475-7516/2026/03/026","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/03/026","url":null,"abstract":"Galactic diffuse emissions in gamma rays and neutrinos arise from interactions of cosmic rays with the interstellar medium and probe the cosmic-ray intensity away from the Solar system. Model predictions for those are influenced by the properties of cosmic-ray sources, and understanding the impact of cosmic-ray sources on Galactic diffuse emissions is key for interpreting measurements by LHAASO, Tibet AS-gamma, IceCube, and the upcoming SWGO. We consider supernova remnants as prototypical cosmic-ray sources and study the impact of their discreteness on the Galactic diffuse emissions in different source injection and near-source transport models in a stochastic Monte Carlo study. Three lessons exemplify the results of our simulations: First, the distributions of Galactic diffuse emission intensities can be described by a mixture model of stable laws and Gaussian distributions. Second, the maximal deviations caused by discrete sources across the sky depend on energy, reaching typically tens of percent in burst-like and energy-dependent escape scenarios but order unity or larger in a time-dependent diffusion scenario. Third, the additional model uncertainty from source stochasticity is subdominant in burst-like and energy-dependent escape scenarios, but becomes sizeable above some tens of TeV in the time-dependent diffusion scenario, where it can help reconcile model predictions with LHAASO measurements. With increased spatial resolution, especially at energies beyond tens of TeV, measurements of Galactic diffuse emissions can be expected to constrain source models and locate cosmic ray sources.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"7 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147380701","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}
Pub Date : 2026-03-09DOI: 10.1088/1475-7516/2026/03/025
Federico Greco
The original axion natural inflation model predicts a tensor-to-scalar ratio exceeding experimental limits. Conversely, in aligned axion inflation, inflation can proceed along trajectories emerging from near a saddle point of the two-field potential and ending through an instability in the orthogonal direction. Such solutions satisfy present observational limits and will be tested by future CMB experiments. Previous studies have suggested the possibility of two distinct inflationary stages separated by a transition characterized by rapid oscillations of the fields. In this work, we demonstrate that the existence of these two stages is a generic feature of the model. We explore a possible phenomenological signature of the transition when a U(1) gauge field is coupled to the axions, namely, the production of gravitational waves (GWs) sourced by gauge quanta generated during the transition. This mechanism produces a feature similar to those seen in spectator axion models or axion inflation with appropriate potentials, i.e. a strongly scale-dependent power spectrum. The scale at which the GW spectrum is produced is determined by the duration of the second inflationary phase. Consequently, the spectrum may peak at different frequencies, potentially detectable by future GW experiments.
{"title":"Production of gravitational waves by inflationary transitions in aligned natural inflation","authors":"Federico Greco","doi":"10.1088/1475-7516/2026/03/025","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/03/025","url":null,"abstract":"The original axion natural inflation model predicts a tensor-to-scalar ratio exceeding experimental limits. Conversely, in aligned axion inflation, inflation can proceed along trajectories emerging from near a saddle point of the two-field potential and ending through an instability in the orthogonal direction. Such solutions satisfy present observational limits and will be tested by future CMB experiments. Previous studies have suggested the possibility of two distinct inflationary stages separated by a transition characterized by rapid oscillations of the fields. In this work, we demonstrate that the existence of these two stages is a generic feature of the model. We explore a possible phenomenological signature of the transition when a U(1) gauge field is coupled to the axions, namely, the production of gravitational waves (GWs) sourced by gauge quanta generated during the transition. This mechanism produces a feature similar to those seen in spectator axion models or axion inflation with appropriate potentials, i.e. a strongly scale-dependent power spectrum. The scale at which the GW spectrum is produced is determined by the duration of the second inflationary phase. Consequently, the spectrum may peak at different frequencies, potentially detectable by future GW experiments.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"55 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147380700","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}
Pub Date : 2026-03-09DOI: 10.1088/1475-7516/2026/03/024
Lorenzo Giombi, Jani Dahl and Mark Hindmarsh
We calculate the gravitational wave power spectrum from sound waves in a cosmological first-order phase transition in the unexplored regime of large bubbles, by which we mean that the mean bubble spacing R* is a non-negligible fraction of the Hubble length ℋ*-1, i.e. R*ℋ* ≲ 𝒪(1). Since the amplitude of the gravitational wave signal increases with R*ℋ*, this is also the loud signal regime. In this regime the effects of gravity, hitherto neglected, become relevant. We carry out the calculation in cosmological perturbation theory expanding in the parameter R*ℋ*, or bubble over Hubble radius. The leading-order term is the standard result for acoustic production of gravitational waves. At next-to-leading-order we find three novel contributions: two contributions arise from general relativistic corrections to the dynamics of both sound waves and gravitational waves. A third contribution comes from secondary gravitational waves induced by curvature perturbations. These contributions suppress the gravitational wave peak amplitude. The suppression factor relative to the leading-order contribution scales as (R*ℋ*)2, and also depends on other transition parameters, such as the sound speed cs, the duration of the acoustic source, and the peak wavenumber of the velocity field kp. We investigate the range 0.3 ≲ R*ℋ* ≲ 0.7 in a simplified model of the velocity field, finding that the suppression factor lies between 2% and 15% when R*ℋ* ≃ 0.5, but is independent of the root mean squared fluid velocity. We provide analytical approximations to the next-to-leading-order corrections, and a recipe to join them smoothly across different frequency regimes. Our work improves the precision of current estimates of the gravitational wave power spectrum in the relatively unexplored regime of phase transitions with large bubbles.
我们计算了宇宙一阶相变中未被探索的大气泡中的声波引力波功率谱，这意味着平均气泡间距R*是哈勃长度h *-1的一个不可忽略的分数，即R* h * >(1)。由于引力波信号的振幅随着R* h *的增大而增大，这也是一个响亮的信号区。在这种制度下，迄今为止被忽视的重力效应变得重要起来。我们在宇宙微扰理论中进行了计算，在参数R* h *中展开，即在哈勃半径上的气泡。第一阶项是引力波声波产生的标准结果。在次一级，我们发现了三个新的贡献：两个贡献来自广义相对论对声波和引力波动力学的修正。第三个贡献来自曲率扰动引起的二次引力波。这些贡献抑制了引力波的峰值振幅。相对于前阶贡献的抑制因子为（R* h *）2，并且还取决于其他过渡参数，如声速cs、声源持续时间和速度场峰值波数kp。研究了速度场简化模型在0.3≤R* h *≈0.7范围内的抑制系数，发现当R* h *≤0.5时，抑制系数在2% ~ 15%之间，且与流体速度的均方根无关。我们提供了次阶校正的解析近似，以及在不同频率范围内平滑地连接它们的配方。我们的工作提高了引力波功率谱目前估计的精度，在相对未开发的大气泡相变制度。
{"title":"Acoustic gravitational waves beyond leading-order in bubble over Hubble radius","authors":"Lorenzo Giombi, Jani Dahl and Mark Hindmarsh","doi":"10.1088/1475-7516/2026/03/024","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/03/024","url":null,"abstract":"We calculate the gravitational wave power spectrum from sound waves in a cosmological first-order phase transition in the unexplored regime of large bubbles, by which we mean that the mean bubble spacing R* is a non-negligible fraction of the Hubble length ℋ*-1, i.e. R*ℋ* ≲ 𝒪(1). Since the amplitude of the gravitational wave signal increases with R*ℋ*, this is also the loud signal regime. In this regime the effects of gravity, hitherto neglected, become relevant. We carry out the calculation in cosmological perturbation theory expanding in the parameter R*ℋ*, or bubble over Hubble radius. The leading-order term is the standard result for acoustic production of gravitational waves. At next-to-leading-order we find three novel contributions: two contributions arise from general relativistic corrections to the dynamics of both sound waves and gravitational waves. A third contribution comes from secondary gravitational waves induced by curvature perturbations. These contributions suppress the gravitational wave peak amplitude. The suppression factor relative to the leading-order contribution scales as (R*ℋ*)2, and also depends on other transition parameters, such as the sound speed cs, the duration of the acoustic source, and the peak wavenumber of the velocity field kp. We investigate the range 0.3 ≲ R*ℋ* ≲ 0.7 in a simplified model of the velocity field, finding that the suppression factor lies between 2% and 15% when R*ℋ* ≃ 0.5, but is independent of the root mean squared fluid velocity. We provide analytical approximations to the next-to-leading-order corrections, and a recipe to join them smoothly across different frequency regimes. Our work improves the precision of current estimates of the gravitational wave power spectrum in the relatively unexplored regime of phase transitions with large bubbles.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"32 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147380699","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}
Pub Date : 2026-03-09DOI: 10.1088/1475-7516/2026/03/023
J.M. Carmona, J.L. Cortés and M.A. Reyes
The 220+570-100PeV neutrino detected by KM3NeT marks the beginning of ultra-high-energy neutrino astronomy and provides a powerful probe of Lorentz Invariance Violation (LIV). In superluminal scenarios, neutrinos can decay through vacuum e-e+ pair emission or neutrino splitting. Previous analyses of the KM3-230213A event relied on simplified survival-probability estimates and, in some cases, used inaccurate decay-width expressions or neglected redshift and threshold effects. In this work we present a unified and self-consistent framework that corrects these issues and applies to both the energy-independent (n = 0) and quadratic (n = 2) superluminal cases. We collect and recast the decay-width and threshold expressions, clarify their flavor dependence, and include a consistent treatment of cosmological propagation. We also assess the impact of cascade regeneration and show that cascade effects are negligible for the purpose of setting LIV bounds. The survival-probability approximation adopted in previous works is therefore justified, while our framework provides a coherent basis for future analyses of superluminal neutrino constraints, which should consistently include possible time-delay signatures.
{"title":"Superluminal constraints from ultra-high-energy neutrino events","authors":"J.M. Carmona, J.L. Cortés and M.A. Reyes","doi":"10.1088/1475-7516/2026/03/023","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/03/023","url":null,"abstract":"The 220+570-100PeV neutrino detected by KM3NeT marks the beginning of ultra-high-energy neutrino astronomy and provides a powerful probe of Lorentz Invariance Violation (LIV). In superluminal scenarios, neutrinos can decay through vacuum e-e+ pair emission or neutrino splitting. Previous analyses of the KM3-230213A event relied on simplified survival-probability estimates and, in some cases, used inaccurate decay-width expressions or neglected redshift and threshold effects. In this work we present a unified and self-consistent framework that corrects these issues and applies to both the energy-independent (n = 0) and quadratic (n = 2) superluminal cases. We collect and recast the decay-width and threshold expressions, clarify their flavor dependence, and include a consistent treatment of cosmological propagation. We also assess the impact of cascade regeneration and show that cascade effects are negligible for the purpose of setting LIV bounds. The survival-probability approximation adopted in previous works is therefore justified, while our framework provides a coherent basis for future analyses of superluminal neutrino constraints, which should consistently include possible time-delay signatures.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"75 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147380698","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}
Pub Date : 2026-03-09DOI: 10.1088/1475-7516/2026/03/027
Zucheng Gao, Azadeh Moradinezhad Dizgah and Zvonimir Vlah
Detecting parity violation on cosmological scales would provide a striking clue to new physics. Large-scale structure offers the raw statistical power — many three-dimensional modes — to make such tests. However, for scalar observables, like galaxy clustering, the leading parity-sensitive observable is the trispectrum, whose high dimensionality makes the measurement and noise estimation challenging. We present two late-time parity-odd kurto spectra that compress the parity-odd scalar trispectrum into one-dimensional, power-spectrum-like observables. They are built by correlating (i) two appropriately weighted quadratic composite fields, or (ii) a linear and cubic composite field, constructed from dark matter (DM) or galaxy overdensity fields. We develop an FFTLog pipeline for efficient theoretical predictions of the two observables. We then validate the estimators for a specific parity-odd primordial template on perturbative DM field, and on DM and halo fields in full N-body Quijote simulations, with and without parity-odd initial conditions, in real and redshift space. For DM, the variance is dominated by the parity-even contribution — i.e., the gravitationally induced parity-even trispectrum — and is efficiently suppressed by phase-matched fiducial subtraction. For halos, discreteness-driven stochasticity dominates and is not appreciably reduced by subtraction; however, optimal weighting and halo-matter cross kurto spectra considerably mitigate this noise and enhance the signal. Using controlled down-sampling of the matter field, we empirically calibrate how the parity-even variance scales with number density and volume, and provide an illustrative forecast for the detectability of parity-odd kurto spectra in a Euclid-like spectroscopic galaxy survey.
{"title":"Parity in composite-field galaxy correlators","authors":"Zucheng Gao, Azadeh Moradinezhad Dizgah and Zvonimir Vlah","doi":"10.1088/1475-7516/2026/03/027","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/03/027","url":null,"abstract":"Detecting parity violation on cosmological scales would provide a striking clue to new physics. Large-scale structure offers the raw statistical power — many three-dimensional modes — to make such tests. However, for scalar observables, like galaxy clustering, the leading parity-sensitive observable is the trispectrum, whose high dimensionality makes the measurement and noise estimation challenging. We present two late-time parity-odd kurto spectra that compress the parity-odd scalar trispectrum into one-dimensional, power-spectrum-like observables. They are built by correlating (i) two appropriately weighted quadratic composite fields, or (ii) a linear and cubic composite field, constructed from dark matter (DM) or galaxy overdensity fields. We develop an FFTLog pipeline for efficient theoretical predictions of the two observables. We then validate the estimators for a specific parity-odd primordial template on perturbative DM field, and on DM and halo fields in full N-body Quijote simulations, with and without parity-odd initial conditions, in real and redshift space. For DM, the variance is dominated by the parity-even contribution — i.e., the gravitationally induced parity-even trispectrum — and is efficiently suppressed by phase-matched fiducial subtraction. For halos, discreteness-driven stochasticity dominates and is not appreciably reduced by subtraction; however, optimal weighting and halo-matter cross kurto spectra considerably mitigate this noise and enhance the signal. Using controlled down-sampling of the matter field, we empirically calibrate how the parity-even variance scales with number density and volume, and provide an illustrative forecast for the detectability of parity-odd kurto spectra in a Euclid-like spectroscopic galaxy survey.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"50 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147380702","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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