Pub Date : 2026-02-16DOI: 10.1088/1475-7516/2026/02/053
Mayur Abhisheki and Prasanta Kumar Das
In this work, we study the early universe inflation and the post-inflation reheating era employing an inverse tangent potential of the form V = V0 ·[tan-1(κϕ/mp)]2, where κ is a free parameter of the potential and mp is the reduced Planck mass. We derive the slow roll parameters, the number of e-folds(N), the scalar spectral index ns, the tensor-to-scalar ratio r, and the tensor spectral index nT for the inverse tangent potential. We examine the inflationary observables using the data of the Planck-2018 and recent ACT collaboration and obtain constraints on the potential parameter κ. We also employ a reheating analysis by invoking the conservation of entropy between today and the time when reheating starts. We obtain bounds on the reheating temperature Tre and the number of e-folds of the reheating Nre using the spectral-index ns constraints from Planck 2018 and the ACT results. We show that this inverse-tangent potential can act as an alternative to the standard inflationary potentials like Starobinsky which are excluded at 2σ level by the recent sixth data release (DR6) of the Atacama Cosmology Telescope (ACT) collaboration.
{"title":"Reheating and inflationary dynamics driven by an inverse tangent potential","authors":"Mayur Abhisheki and Prasanta Kumar Das","doi":"10.1088/1475-7516/2026/02/053","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/02/053","url":null,"abstract":"In this work, we study the early universe inflation and the post-inflation reheating era employing an inverse tangent potential of the form V = V0 ·[tan-1(κϕ/mp)]2, where κ is a free parameter of the potential and mp is the reduced Planck mass. We derive the slow roll parameters, the number of e-folds(N), the scalar spectral index ns, the tensor-to-scalar ratio r, and the tensor spectral index nT for the inverse tangent potential. We examine the inflationary observables using the data of the Planck-2018 and recent ACT collaboration and obtain constraints on the potential parameter κ. We also employ a reheating analysis by invoking the conservation of entropy between today and the time when reheating starts. We obtain bounds on the reheating temperature Tre and the number of e-folds of the reheating Nre using the spectral-index ns constraints from Planck 2018 and the ACT results. We show that this inverse-tangent potential can act as an alternative to the standard inflationary potentials like Starobinsky which are excluded at 2σ level by the recent sixth data release (DR6) of the Atacama Cosmology Telescope (ACT) collaboration.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"13 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146198640","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 : 2026-02-16DOI: 10.1088/1475-7516/2026/02/049
Sudhava Yadav, Akash Yadav and K.K. Venkataratnam
We study reheating in sombrero-type symmetry-breaking potentials, emphasizing the role of the post-inflationary equation-of-state parameter(ω̅re) in shaping observable predictions. By exploring the allowed range of ω̅re, we derive reheating temperature, e-fold counts, and inflationary observables, showing that the double well potential satisfies Planck+BK18+BAO constraints on ns and r. The analysis underscores reheating as a critical link between theoretical potentials and CMB data. In addition, the holographic sombrero realization is examined as a benchmark, with our results mapping its phenomenological boundaries. This work illustrates how reheating studies sharpen constraints and guide refinements of unified inflationary scenarios.
{"title":"Reheating study of sombrero-type symmetry-breaking potentials","authors":"Sudhava Yadav, Akash Yadav and K.K. Venkataratnam","doi":"10.1088/1475-7516/2026/02/049","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/02/049","url":null,"abstract":"We study reheating in sombrero-type symmetry-breaking potentials, emphasizing the role of the post-inflationary equation-of-state parameter(ω̅re) in shaping observable predictions. By exploring the allowed range of ω̅re, we derive reheating temperature, e-fold counts, and inflationary observables, showing that the double well potential satisfies Planck+BK18+BAO constraints on ns and r. The analysis underscores reheating as a critical link between theoretical potentials and CMB data. In addition, the holographic sombrero realization is examined as a benchmark, with our results mapping its phenomenological boundaries. This work illustrates how reheating studies sharpen constraints and guide refinements of unified inflationary scenarios.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"18 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146198637","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 : 2026-02-13DOI: 10.1088/1475-7516/2026/02/042
C.P. Burgess, R. Holman and Greg Kaplanek
We re-examine the decoherence rate of primordial fluctuations within minimal inflationary models, using only the gravitational interactions required for the underlying fluctuation-generation mechanism itself. Since gravity provides the weakest interactions the result provides a plausible floor on the rate of primordial decoherence. Previous calculations (arXiv:2211.11046) did so using only a subset of these interactions, motivated by assuming both system and environment were super-Hubble. We extend this by including the effects on super-Hubble modes of all gravitational interactions amongst scalar fluctuations at leading order in H/Mp (and so need not restrict the decohering environment to being super-Hubble). We show how the decohering evolution becomes Markovian for super-Hubble modes, without the need to appeal to truncations (like the `rotating wave' approximation) that are often used in optics but can be inapprorpriate for cosmology. We find that the dominant contribution comes from the nonlocal cubic interactions obtained by solving the constraints. We identify UV divergences systematically and verify thereby that the leading part of the purity evolution is UV finite. In the end we find a decoherence rate that grows in the super-Hubble regime significantly faster than found earlier. We take the preliminary steps to resum this result to late times and briefly discuss why they are more complicated than for earlier calculations.
{"title":"Inflationary decoherence from the gravitational floor","authors":"C.P. Burgess, R. Holman and Greg Kaplanek","doi":"10.1088/1475-7516/2026/02/042","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/02/042","url":null,"abstract":"We re-examine the decoherence rate of primordial fluctuations within minimal inflationary models, using only the gravitational interactions required for the underlying fluctuation-generation mechanism itself. Since gravity provides the weakest interactions the result provides a plausible floor on the rate of primordial decoherence. Previous calculations (arXiv:2211.11046) did so using only a subset of these interactions, motivated by assuming both system and environment were super-Hubble. We extend this by including the effects on super-Hubble modes of all gravitational interactions amongst scalar fluctuations at leading order in H/Mp (and so need not restrict the decohering environment to being super-Hubble). We show how the decohering evolution becomes Markovian for super-Hubble modes, without the need to appeal to truncations (like the `rotating wave' approximation) that are often used in optics but can be inapprorpriate for cosmology. We find that the dominant contribution comes from the nonlocal cubic interactions obtained by solving the constraints. We identify UV divergences systematically and verify thereby that the leading part of the purity evolution is UV finite. In the end we find a decoherence rate that grows in the super-Hubble regime significantly faster than found earlier. We take the preliminary steps to resum this result to late times and briefly discuss why they are more complicated than for earlier calculations.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"113 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184321","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 : 2026-02-13DOI: 10.1088/1475-7516/2026/02/043
Micol Benetti, David A. Cook and Saulo Carneiro
We investigate a relativistic cosmological model with background rotation, sourced by a non-perfect fluid with anisotropic stress. A modified version of the CLASS Boltzmann code is employed to perform Monte Carlo Markov Chain analyses against Cosmic Microwave Background (CMB) and late-time datasets. The results show that current CMB data constrain the present-day rotation parameter to be negligible. As a consequence, the derived cosmological parameters remain consistent with the standard ΛCDM values. In contrast, late-time probes such as Type Ia supernovae (SNe) and Baryonic Acoustic Oscillations (BAO) allow for a higher level of rotation and yield an increased Hubble constant. However, this comes at the cost of a higher σ8, which remains in tension with DES-Y3 measurement. Combining CMB, SNe and BAO data confirms the preference for non-rotation.
{"title":"Can cosmic rotation resolve the Hubble tension? Constraints from CMB and large-scale structure","authors":"Micol Benetti, David A. Cook and Saulo Carneiro","doi":"10.1088/1475-7516/2026/02/043","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/02/043","url":null,"abstract":"We investigate a relativistic cosmological model with background rotation, sourced by a non-perfect fluid with anisotropic stress. A modified version of the CLASS Boltzmann code is employed to perform Monte Carlo Markov Chain analyses against Cosmic Microwave Background (CMB) and late-time datasets. The results show that current CMB data constrain the present-day rotation parameter to be negligible. As a consequence, the derived cosmological parameters remain consistent with the standard ΛCDM values. In contrast, late-time probes such as Type Ia supernovae (SNe) and Baryonic Acoustic Oscillations (BAO) allow for a higher level of rotation and yield an increased Hubble constant. However, this comes at the cost of a higher σ8, which remains in tension with DES-Y3 measurement. Combining CMB, SNe and BAO data confirms the preference for non-rotation.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"331 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184322","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 : 2026-02-13DOI: 10.1088/1475-7516/2026/02/044
A. Mata Román, I. Ocampo and S. Nesseris
In this work we quantify the ability of the upcoming SPHEREx survey to constrain cosmological observables and test the internal consistency of the cosmological constant and cold dark matter (ΛCDM) model. Using Fisher matrix forecasting, we assess the expected precision on Baryon Acoustic Oscillations (BAO) observables, such as the angular diameter distance DA(z) and the Hubble parameter H(z). We further explore SPHEREx's potential to probe some of the fundamental assumptions of large-scale spatial homogeneity and isotropy, through model-independent reconstructions of several consistency tests of the ΛCDM model. In addition, we also examine the effect of the model dependence of the resulting Fisher and covariance matrices, using a neural network (NN) classification approach. We find that, while it is commonly assumed the covariance matrix depends weakly on the model, in fact the NN can very accurately (∼ 98%) detect the underlying fiducial cosmological model based solely on the covariance matrix of the data, thus challenging this assumption. This model dependence, often neglected in standard analyses, can be naturally incorporated within simulation-based inference frameworks, which offer a flexible alternative for capturing such effects.
{"title":"Forecast constraints on null tests of the ΛCDM model with SPHEREx","authors":"A. Mata Román, I. Ocampo and S. Nesseris","doi":"10.1088/1475-7516/2026/02/044","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/02/044","url":null,"abstract":"In this work we quantify the ability of the upcoming SPHEREx survey to constrain cosmological observables and test the internal consistency of the cosmological constant and cold dark matter (ΛCDM) model. Using Fisher matrix forecasting, we assess the expected precision on Baryon Acoustic Oscillations (BAO) observables, such as the angular diameter distance DA(z) and the Hubble parameter H(z). We further explore SPHEREx's potential to probe some of the fundamental assumptions of large-scale spatial homogeneity and isotropy, through model-independent reconstructions of several consistency tests of the ΛCDM model. In addition, we also examine the effect of the model dependence of the resulting Fisher and covariance matrices, using a neural network (NN) classification approach. We find that, while it is commonly assumed the covariance matrix depends weakly on the model, in fact the NN can very accurately (∼ 98%) detect the underlying fiducial cosmological model based solely on the covariance matrix of the data, thus challenging this assumption. This model dependence, often neglected in standard analyses, can be naturally incorporated within simulation-based inference frameworks, which offer a flexible alternative for capturing such effects.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"18 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184396","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 : 2026-02-13DOI: 10.1088/1475-7516/2026/02/046
M. Escudero, G. Jackson, M. Laine and S. Sandner
Cosmological determinations of the number of relativistic neutrino species, Neff, are becoming increasingly accurate, and further improvements are expected both from CMB and BBN data. Given this context, we update the evaluation of Neff and the current entropy density via the momentum-averaged approach. This allows for a numerically fast description of neutrino decoupling, easily portable to an array of new physics scenarios. We revisit all aspects of this approach, including collision terms with full electron mass dependence, finite temperature QED corrections to the equation of state, neutrino oscillations, and the modelling of neutrino ensembles with effective chemical potentials. For integrated observables, our results differ by less than 0.04% from the solution of the momentum-dependent evolution equation. We outline how to extend the approach to BSM settings, and will highlight its power in Part II. To facilitate the practical implementation, we release a Mathematica and python code within nudec_BSM_v2, easily linkable to BBN codes.
{"title":"Fast and flexible neutrino decoupling. Part I. The Standard Model","authors":"M. Escudero, G. Jackson, M. Laine and S. Sandner","doi":"10.1088/1475-7516/2026/02/046","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/02/046","url":null,"abstract":"Cosmological determinations of the number of relativistic neutrino species, Neff, are becoming increasingly accurate, and further improvements are expected both from CMB and BBN data. Given this context, we update the evaluation of Neff and the current entropy density via the momentum-averaged approach. This allows for a numerically fast description of neutrino decoupling, easily portable to an array of new physics scenarios. We revisit all aspects of this approach, including collision terms with full electron mass dependence, finite temperature QED corrections to the equation of state, neutrino oscillations, and the modelling of neutrino ensembles with effective chemical potentials. For integrated observables, our results differ by less than 0.04% from the solution of the momentum-dependent evolution equation. We outline how to extend the approach to BSM settings, and will highlight its power in Part II. To facilitate the practical implementation, we release a Mathematica and python code within nudec_BSM_v2, easily linkable to BBN codes.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"99 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184324","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 : 2026-02-13DOI: 10.1088/1475-7516/2026/02/045
Guillem Domènech, Alexander Ganz and Apostolos Tsabodimos
Disformal couplings to fermions lead to a unique derivative coupling to the axial fermionic current, which contains higher derivatives in general. We derive general conditions on consistent disformal couplings by requiring the absence of higher time derivatives, as they typically lead to ghost degrees of freedom. For a two-scalar field disformal transformation, we show that the consistent disformal coupling must have a degenerate field space metric. This allows us to explore consistent, new two-scalar field modified gravity models. We show that the transformation of the Einstein-Hilbert action leads to two-field Horndeski or two-field DHOST theories. Our formalism also applies to disformal transformations with higher derivatives. We derive the consistent subclasses of disformal transformations that include second derivatives of a scalar field and first derivatives of a vector field that lead to generalized U-DHOST and degenerate beyond generalized Proca theories.
{"title":"On the consistent disformal couplings to fermions","authors":"Guillem Domènech, Alexander Ganz and Apostolos Tsabodimos","doi":"10.1088/1475-7516/2026/02/045","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/02/045","url":null,"abstract":"Disformal couplings to fermions lead to a unique derivative coupling to the axial fermionic current, which contains higher derivatives in general. We derive general conditions on consistent disformal couplings by requiring the absence of higher time derivatives, as they typically lead to ghost degrees of freedom. For a two-scalar field disformal transformation, we show that the consistent disformal coupling must have a degenerate field space metric. This allows us to explore consistent, new two-scalar field modified gravity models. We show that the transformation of the Einstein-Hilbert action leads to two-field Horndeski or two-field DHOST theories. Our formalism also applies to disformal transformations with higher derivatives. We derive the consistent subclasses of disformal transformations that include second derivatives of a scalar field and first derivatives of a vector field that lead to generalized U-DHOST and degenerate beyond generalized Proca theories.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"31 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184335","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 : 2026-02-13DOI: 10.1088/1475-7516/2026/02/040
Shengyu He, Jiaxi Yu, Antoine Rocher, Daniel Forero-Sánchez, Jean-Paul Kneib, Cheng Zhao, Etienne Burtin and Jiamin Hou
Spectroscopic redshift errors, including redshift uncertainty and catastrophic failures, can bias cosmological measurements from galaxy clustering at sub-percent level. In this work, we investigate their impact on the full-shape analysis using contaminated mock catalogs. We find that redshift uncertainty introduces a scale-dependent damping effect on the power spectrum, which is absorbed by counterterms in clustering model, keeping parameter biases below 5%. Catastrophic failures suppress the power spectrum amplitude by an approximately constant factor, which scales with the catastrophic rate fc. While this effect is negligible for DESI galaxy populations (fc = 1%), the slitless-like errors, combining redshift uncertainty with fc = 5% catastrophics, introduce significant biases in cosmological constraints. In this case, we find 6% to 16% shifts (∼2.2σ level) in estimating the fractional growth rate df ≡ f/ffid and the log primordial amplitude ln(1010As). Applying the correction factor (1-fc)2 on the galaxy power spectrum mitigates the bias but weakens the parameter constraints due to new degeneracies. Alternatively, fixing fc to its expected value restores the constraining power with a modest bias of 1.0σ. Our results indicate that for space-based slitless surveys such as Euclid, at minimum accurate estimation of fc and its incorporation into the clustering model are necessary to get unbiased cosmological inference. Extending to evolving dark energy and massive neutrino cosmologies, redshift errors do not bias the dark energy properties parametrized by w0 and wa, but can degrade constraints on the summed neutrino mass ∑mν by up to 80% in the worst case.
{"title":"The impact of spectroscopic redshift errors on cosmological measurements","authors":"Shengyu He, Jiaxi Yu, Antoine Rocher, Daniel Forero-Sánchez, Jean-Paul Kneib, Cheng Zhao, Etienne Burtin and Jiamin Hou","doi":"10.1088/1475-7516/2026/02/040","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/02/040","url":null,"abstract":"Spectroscopic redshift errors, including redshift uncertainty and catastrophic failures, can bias cosmological measurements from galaxy clustering at sub-percent level. In this work, we investigate their impact on the full-shape analysis using contaminated mock catalogs. We find that redshift uncertainty introduces a scale-dependent damping effect on the power spectrum, which is absorbed by counterterms in clustering model, keeping parameter biases below 5%. Catastrophic failures suppress the power spectrum amplitude by an approximately constant factor, which scales with the catastrophic rate fc. While this effect is negligible for DESI galaxy populations (fc = 1%), the slitless-like errors, combining redshift uncertainty with fc = 5% catastrophics, introduce significant biases in cosmological constraints. In this case, we find 6% to 16% shifts (∼2.2σ level) in estimating the fractional growth rate df ≡ f/ffid and the log primordial amplitude ln(1010As). Applying the correction factor (1-fc)2 on the galaxy power spectrum mitigates the bias but weakens the parameter constraints due to new degeneracies. Alternatively, fixing fc to its expected value restores the constraining power with a modest bias of 1.0σ. Our results indicate that for space-based slitless surveys such as Euclid, at minimum accurate estimation of fc and its incorporation into the clustering model are necessary to get unbiased cosmological inference. Extending to evolving dark energy and massive neutrino cosmologies, redshift errors do not bias the dark energy properties parametrized by w0 and wa, but can degrade constraints on the summed neutrino mass ∑mν by up to 80% in the worst case.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"14 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184320","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 : 2026-02-13DOI: 10.1088/1475-7516/2026/02/041
Matheus Duarte and Vitor de Souza
We investigate the impact of Lorentz invariance violation (LIV) on radiation processes in astrophysical sources, focusing on synchrotron and inverse Compton interactions. We derive modified expressions for radiated power and photon energy under LIV assumptions and incorporate them into first-order Fermi acceleration models. Our analysis reveals energy thresholds beyond which LIV, within a kinematic framework, significantly alters particle dynamics and photon spectra, introducing non-physical divergences that highlight limitations in perturbative approaches. We model synchrotron self-Compton (SSC) emission in the presence of LIV and assess its consequences for photon fluxes from blazars, including Markarian 501 and the BL Lac population. LIV introduces distinct high-energy emission regions that deviate from standard expectations. Comparisons with observational data, particularly upper limits from the Pierre Auger Observatory, suggest that future multi-messenger observations, together with the full analysis of particle's trajectories, could constrain LIV parameters through the non-detection of such excesses.
{"title":"Effects of Lorentz invariance violation on charged particles and photon production in astrophysical sources","authors":"Matheus Duarte and Vitor de Souza","doi":"10.1088/1475-7516/2026/02/041","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/02/041","url":null,"abstract":"We investigate the impact of Lorentz invariance violation (LIV) on radiation processes in astrophysical sources, focusing on synchrotron and inverse Compton interactions. We derive modified expressions for radiated power and photon energy under LIV assumptions and incorporate them into first-order Fermi acceleration models. Our analysis reveals energy thresholds beyond which LIV, within a kinematic framework, significantly alters particle dynamics and photon spectra, introducing non-physical divergences that highlight limitations in perturbative approaches. We model synchrotron self-Compton (SSC) emission in the presence of LIV and assess its consequences for photon fluxes from blazars, including Markarian 501 and the BL Lac population. LIV introduces distinct high-energy emission regions that deviate from standard expectations. Comparisons with observational data, particularly upper limits from the Pierre Auger Observatory, suggest that future multi-messenger observations, together with the full analysis of particle's trajectories, could constrain LIV parameters through the non-detection of such excesses.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"102 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184339","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 : 2026-02-12DOI: 10.1088/1475-7516/2026/02/039
T. Bertólez-Martínez, J. López-Sarrión and J. Salvado
The high densities in the early Universe provide a unique laboratory to constrain couplings between feebly interacting particles, such as dark matter and neutrinos. In this article, we study how Big Bang Nucleosynthesis can constrain models of Ultra-Light Dark Matter diagonally coupled to neutrinos. We follow an adiabatic formalism which allows to average-out the rapid oscillations of the Dark Matter field and consistently take into account the feedback between the neutrino and the Dark Matter fields. This feedback alters the early Universe dynamics, causing the Dark Matter energy density to scale as radiation, while the neutrino mass scales as a^-1. These two effects modify primordial element abundances by modifying interaction rates and the expansion rate during nucleosynthesis. Then, we use primordial abundances to obtain leading cosmological bounds on the coupling in the range mϕ/eV ∈ (10-22,10-17), namely g ≲ 0.13(mϕ/eV) for mϕ ≳ 3 × 10-20 eV andg ≲ 1.8 × 10-11√(mϕ/eV) for mϕ ≳ 3 × 10-20 eV. This consistent cosmological treatment emphasizes that, in the mass interval where its physical assumptions hold, neutrino masses cannot be generated refractively by a direct coupling with an Ultra-Light Dark Matter field.
早期宇宙的高密度提供了一个独特的实验室来约束弱相互作用粒子之间的耦合，比如暗物质和中微子。在本文中，我们研究了大爆炸核合成如何约束超轻暗物质与中微子对角线耦合的模型。我们遵循绝热形式，它允许平均出暗物质场的快速振荡，并始终考虑到中微子和暗物质场之间的反馈。这种反馈改变了早期的宇宙动力学，导致暗物质的能量密度按辐射的比例缩放，而中微子的质量按^-1的比例缩放。这两种效应通过改变核合成过程中的相互作用速率和膨胀速率来改变原始元素的丰度。然后，我们利用原始丰度得到了在mϕ/eV∈(10-22,10-17)范围内耦合的领先宇宙学界，即对于mϕ > 3 × 10-20 eV, g > 0.13(mϕ/eV)，对于mϕ > 3 × 10-20 eV, g > 1.8 × 10-11√（mϕ/eV）。这种一致的宇宙学处理强调，在其物理假设成立的质量区间内，中微子质量不能通过与超轻暗物质场的直接耦合而折射产生。
{"title":"BBN bounds on neutrinophilic ultralight Dark Matter","authors":"T. Bertólez-Martínez, J. López-Sarrión and J. Salvado","doi":"10.1088/1475-7516/2026/02/039","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/02/039","url":null,"abstract":"The high densities in the early Universe provide a unique laboratory to constrain couplings between feebly interacting particles, such as dark matter and neutrinos. In this article, we study how Big Bang Nucleosynthesis can constrain models of Ultra-Light Dark Matter diagonally coupled to neutrinos. We follow an adiabatic formalism which allows to average-out the rapid oscillations of the Dark Matter field and consistently take into account the feedback between the neutrino and the Dark Matter fields. This feedback alters the early Universe dynamics, causing the Dark Matter energy density to scale as radiation, while the neutrino mass scales as a^-1. These two effects modify primordial element abundances by modifying interaction rates and the expansion rate during nucleosynthesis. Then, we use primordial abundances to obtain leading cosmological bounds on the coupling in the range mϕ/eV ∈ (10-22,10-17), namely g ≲ 0.13(mϕ/eV) for mϕ ≳ 3 × 10-20 eV andg ≲ 1.8 × 10-11√(mϕ/eV) for mϕ ≳ 3 × 10-20 eV. This consistent cosmological treatment emphasizes that, in the mass interval where its physical assumptions hold, neutrino masses cannot be generated refractively by a direct coupling with an Ultra-Light Dark Matter field.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"98 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160307","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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