Pub Date : 2025-01-09DOI: 10.1088/1475-7516/2025/01/035
Sunghyun Kang, Stefano Scopel and Gaurav Tomar
We use the Migdal effect to extend to low masses the bounds on each of the effective couplings of the non-relativistic effective field theory of a WIMP of mass mχ and spin 1/2 that interacts inelastically with nuclei by either upscattering to a heavier state with mass splitting δ > 0 or by downscattering to a lighter state with δ < 0. In order to do so we perform a systematic analysis of the Migdal bounds in the mχ-δ parameter space comparing them to those from nuclear recoil searches. The Migdal effect allows to significantly extend to low WIMP masses the nuclear recoil bounds for δ < 0. In this case the bounds are driven by XENON1T, except when δ is vanishing or very small, when, depending on the WIMP-nucleus interaction, in the lower end of the mχ range either DS50 or SuperCDMS are more constraining. On the other hand, when δ > 0 and the WIMP particle upscatters to a heavier state nuclear recoil bounds are stronger than those from the Migdal effect.
{"title":"Low-mass constraints on WIMP effective models of inelastic scattering using the Migdal effect","authors":"Sunghyun Kang, Stefano Scopel and Gaurav Tomar","doi":"10.1088/1475-7516/2025/01/035","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/035","url":null,"abstract":"We use the Migdal effect to extend to low masses the bounds on each of the effective couplings of the non-relativistic effective field theory of a WIMP of mass mχ and spin 1/2 that interacts inelastically with nuclei by either upscattering to a heavier state with mass splitting δ > 0 or by downscattering to a lighter state with δ < 0. In order to do so we perform a systematic analysis of the Migdal bounds in the mχ-δ parameter space comparing them to those from nuclear recoil searches. The Migdal effect allows to significantly extend to low WIMP masses the nuclear recoil bounds for δ < 0. In this case the bounds are driven by XENON1T, except when δ is vanishing or very small, when, depending on the WIMP-nucleus interaction, in the lower end of the mχ range either DS50 or SuperCDMS are more constraining. On the other hand, when δ > 0 and the WIMP particle upscatters to a heavier state nuclear recoil bounds are stronger than those from the Migdal effect.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"37 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936729","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 : 2025-01-09DOI: 10.1088/1475-7516/2025/01/036
Sandeep Kumar Acharya and Paz Beniamini
We constrain the redshift dependence of (rest frame) host galaxy dispersion measures of localized Fast Radio Bursts (FRBs) by assuming it to vary as a simple power law (∝ (1+z)α). We simultaneously fit α as well as the host dispersion measure to the data of FRBs with known redshifts. We find that α between 0 to 1 is preferred depending upon our modelling choices. Current data can constrain |α| ≲ 2 at a 68 percent confidence interval. Such constraints have implications for our understanding of galaxy formation and can be used to inform galaxy and large scale simulations.
{"title":"Redshift dependence of FRB host dispersion measures across cosmic epochs","authors":"Sandeep Kumar Acharya and Paz Beniamini","doi":"10.1088/1475-7516/2025/01/036","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/036","url":null,"abstract":"We constrain the redshift dependence of (rest frame) host galaxy dispersion measures of localized Fast Radio Bursts (FRBs) by assuming it to vary as a simple power law (∝ (1+z)α). We simultaneously fit α as well as the host dispersion measure to the data of FRBs with known redshifts. We find that α between 0 to 1 is preferred depending upon our modelling choices. Current data can constrain |α| ≲ 2 at a 68 percent confidence interval. Such constraints have implications for our understanding of galaxy formation and can be used to inform galaxy and large scale simulations.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"14 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936730","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 : 2025-01-09DOI: 10.1088/1475-7516/2025/01/041
Eugeny Babichev, Christos Charmousis, Benjamin Muntz, Antonio Padilla and Ippocratis D. Saltas
We revisit multi-messenger constraints from neutron star mergers on the speed of propagation of gravitational and electromagnetic waves in Horndeski and beyond Horndeski theories. By considering non-trivial couplings between the dark energy field and the electromagnetic sector, the electromagnetic wave can propagate through the cosmological background at non-unit speed, altering the phenomenological constraints on its gravitational counterpart. In particular, we show that recent models derived from a Kaluza-Klein compactification of higher dimensional Horndeski models fall into a broader class of theories disformally related to those whose gravitational waves propagate with unit speed. This disformal equivalence can, however, be broken by the gravitational couplings to other sectors with interesting phenomenological consequences. We also consider higher order couplings between the scalar and the photon with second order field equations, and show that they are not compatible with constraints coming from multi-messenger speed tests and the decay of the gravitational wave.
{"title":"Horndeski speed tests with scalar-photon couplings","authors":"Eugeny Babichev, Christos Charmousis, Benjamin Muntz, Antonio Padilla and Ippocratis D. Saltas","doi":"10.1088/1475-7516/2025/01/041","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/041","url":null,"abstract":"We revisit multi-messenger constraints from neutron star mergers on the speed of propagation of gravitational and electromagnetic waves in Horndeski and beyond Horndeski theories. By considering non-trivial couplings between the dark energy field and the electromagnetic sector, the electromagnetic wave can propagate through the cosmological background at non-unit speed, altering the phenomenological constraints on its gravitational counterpart. In particular, we show that recent models derived from a Kaluza-Klein compactification of higher dimensional Horndeski models fall into a broader class of theories disformally related to those whose gravitational waves propagate with unit speed. This disformal equivalence can, however, be broken by the gravitational couplings to other sectors with interesting phenomenological consequences. We also consider higher order couplings between the scalar and the photon with second order field equations, and show that they are not compatible with constraints coming from multi-messenger speed tests and the decay of the gravitational wave.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"30 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936773","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 : 2025-01-09DOI: 10.1088/1475-7516/2025/01/024
Adamu Issifu, Débora P. Menezes, Zeinab Rezaei and Tobias Frederico
This work investigates the evolution of proto-neutron stars (PNSs) from birth as neutrino-rich objects to maturity as cold-catalyzed neutrino-poor objects with nucleonic and non-nucleonic degrees of freedom. The focus is on the star's core where the nucleons, hyperons, and the Δ-isobars are expected to dissolve into a “soup” of deconfined quarks, at higher baryon densities, to establish a possible hadron-quark phase transition. We separately calculate the nuclear equations of state (EoS) for the hadronic matter (composed of all the baryon octet and Δ-isobars) and the strange quark matter (SQM) under the same thermodynamic conditions characteristic of PNS and proto-strange star (PSS) evolution and construct the hybrid EoS using Maxwell's construction. The study allows us to determine the hadron-quark phase transitions along the evolution lines of the star. We observed a phase transition from hadronic matter to quark matter (QM) phase when the neutrinos have completely escaped from the star's core. The EoSs utilized are constrained to meet the 2 M⊙ threshold in accordance with the observational data.
{"title":"Proto-neutron stars with quark cores","authors":"Adamu Issifu, Débora P. Menezes, Zeinab Rezaei and Tobias Frederico","doi":"10.1088/1475-7516/2025/01/024","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/024","url":null,"abstract":"This work investigates the evolution of proto-neutron stars (PNSs) from birth as neutrino-rich objects to maturity as cold-catalyzed neutrino-poor objects with nucleonic and non-nucleonic degrees of freedom. The focus is on the star's core where the nucleons, hyperons, and the Δ-isobars are expected to dissolve into a “soup” of deconfined quarks, at higher baryon densities, to establish a possible hadron-quark phase transition. We separately calculate the nuclear equations of state (EoS) for the hadronic matter (composed of all the baryon octet and Δ-isobars) and the strange quark matter (SQM) under the same thermodynamic conditions characteristic of PNS and proto-strange star (PSS) evolution and construct the hybrid EoS using Maxwell's construction. The study allows us to determine the hadron-quark phase transitions along the evolution lines of the star. We observed a phase transition from hadronic matter to quark matter (QM) phase when the neutrinos have completely escaped from the star's core. The EoSs utilized are constrained to meet the 2 M⊙ threshold in accordance with the observational data.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"51 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936718","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 : 2025-01-09DOI: 10.1088/1475-7516/2025/01/029
Wei-Yu Hu, Kazunori Nakayama, Volodymyr Takhistov and Yong Tang
In the instant preheating scenario efficient particle production occurs immediately following the period of inflationary expansion in the early Universe. We demonstrate that instant preheating predicts unique gravitational wave (GW) signals arising from two distinct origins. One source is the bremsstrahlung GWs produced through the decay of superheavy particles, an inevitable consequence of instant preheating. The other is GWs generated from the nonlinear dynamics of the inflaton and coupled scalar fields. Using numerical simulations, we show that the peak of the GW spectrum shifts depending on the coupling constants of the theory. The detection of these dual GW signatures, characteristic of instant preheating, provides novel opportunities for probing the dynamics of the early Universe.
{"title":"Dual gravitational wave signatures of instant preheating","authors":"Wei-Yu Hu, Kazunori Nakayama, Volodymyr Takhistov and Yong Tang","doi":"10.1088/1475-7516/2025/01/029","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/029","url":null,"abstract":"In the instant preheating scenario efficient particle production occurs immediately following the period of inflationary expansion in the early Universe. We demonstrate that instant preheating predicts unique gravitational wave (GW) signals arising from two distinct origins. One source is the bremsstrahlung GWs produced through the decay of superheavy particles, an inevitable consequence of instant preheating. The other is GWs generated from the nonlinear dynamics of the inflaton and coupled scalar fields. Using numerical simulations, we show that the peak of the GW spectrum shifts depending on the coupling constants of the theory. The detection of these dual GW signatures, characteristic of instant preheating, provides novel opportunities for probing the dynamics of the early Universe.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"23 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936722","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 : 2025-01-09DOI: 10.1088/1475-7516/2025/01/034
Pankaj S. Joshi and Sudip Bhattacharyya
Primordial black hole formation has been discussed widely, when density perturbations in the early universe cause matter to collapse gravitationally, giving rise to these ultra-compact objects. We propose and point out that such a gravitational collapse would also give rise to primordial naked singularities, that would play an important role in the observable features of present universe. We consider two types of collapse scenarios that give rise to event-like and object-like visible singularities within a cosmological background. We briefly discuss implications of primordial naked singularities, including those for dark matter, vis-a-vis primordial black holes.
{"title":"Primordial naked singularities","authors":"Pankaj S. Joshi and Sudip Bhattacharyya","doi":"10.1088/1475-7516/2025/01/034","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/034","url":null,"abstract":"Primordial black hole formation has been discussed widely, when density perturbations in the early universe cause matter to collapse gravitationally, giving rise to these ultra-compact objects. We propose and point out that such a gravitational collapse would also give rise to primordial naked singularities, that would play an important role in the observable features of present universe. We consider two types of collapse scenarios that give rise to event-like and object-like visible singularities within a cosmological background. We briefly discuss implications of primordial naked singularities, including those for dark matter, vis-a-vis primordial black holes.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"328 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936732","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 : 2025-01-09DOI: 10.1088/1475-7516/2025/01/022
Wen-Zheng Chen, Yang Liu, Siyu Li, Bin Hu and Hong Li
Recognizing the impact of contamination from weak gravitational lensing B-modes induced by Large Scale Structure, we examine delensing methods to enhance sensitivity to the tensor-to-scalar ratio r in primordial B-mode detection experiments. This study presents a realistic pipeline to improve r constraints using foreground-cleaned maps with negligible residuals. The pipeline, based on simulations, is adaptable for future experiments. We focus on two delensing approaches: (1) subtracting the gradient-order lensing B-mode template, computed by convolving the E-mode with the lensing potential, from the observed B-mode signal; and (2) remapping observations using the estimated inverse deflection angle. For parameter constraints, we employ three models to reduce r uncertainty and bias, finding consistent uncertainties across models, though biases vary due to the multipole-dependence of the delensing fraction. We demonstrated this pipeline using simulated observation maps from future CMB polarization experiments, which included current representative ground-based small aperture telescopes (sub-1m), next-generation ground-based large aperture telescopes (6m), and highly competitive future space-based medium aperture missions (3m). Results show a delensing efficiency of 40% with the small-aperture telescope alone, increasing to 65% when combined with the large-aperture telescope, and 80% with the satellite mission. These lead to reductions in r uncertainty by 46% for ground-based and 63% for space missions. The most promising method adds the lensing template B-mode as an additional frequency channel, minimizing bias on r.
{"title":"Enhancing primordial B-mode detection: comprehensive delensing pipelines for improved sensitivity to r","authors":"Wen-Zheng Chen, Yang Liu, Siyu Li, Bin Hu and Hong Li","doi":"10.1088/1475-7516/2025/01/022","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/022","url":null,"abstract":"Recognizing the impact of contamination from weak gravitational lensing B-modes induced by Large Scale Structure, we examine delensing methods to enhance sensitivity to the tensor-to-scalar ratio r in primordial B-mode detection experiments. This study presents a realistic pipeline to improve r constraints using foreground-cleaned maps with negligible residuals. The pipeline, based on simulations, is adaptable for future experiments. We focus on two delensing approaches: (1) subtracting the gradient-order lensing B-mode template, computed by convolving the E-mode with the lensing potential, from the observed B-mode signal; and (2) remapping observations using the estimated inverse deflection angle. For parameter constraints, we employ three models to reduce r uncertainty and bias, finding consistent uncertainties across models, though biases vary due to the multipole-dependence of the delensing fraction. We demonstrated this pipeline using simulated observation maps from future CMB polarization experiments, which included current representative ground-based small aperture telescopes (sub-1m), next-generation ground-based large aperture telescopes (6m), and highly competitive future space-based medium aperture missions (3m). Results show a delensing efficiency of 40% with the small-aperture telescope alone, increasing to 65% when combined with the large-aperture telescope, and 80% with the satellite mission. These lead to reductions in r uncertainty by 46% for ground-based and 63% for space missions. The most promising method adds the lensing template B-mode as an additional frequency channel, minimizing bias on r.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"75 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939835","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 : 2025-01-09DOI: 10.1088/1475-7516/2025/01/025
A. Ashrafzadeh, M. Solbi, S. Heydari and K. Karami
Here, we explore the formation of primordial black holes (PBHs) within a scalar field inflationary model coupled to the Gauss-Bonnet (GB) term, incorporating the low-scale spontaneously broken supersymmetric (SB SUSY) potential. The coupling function amplifies the curvature perturbations, consequently leading to the formation of PBHs and detectable secondary gravitational waves (GWs). Through the adjustment of the model parameters, the inflaton can be decelerated during an ultra-slow-roll (USR) phase, thereby augmenting curvature perturbations. Beside the observational constraints, the swampland criteria are investigated. Our computations forecast the formation of PBHs with masses around 𝒪(10)M⊙, aligning with the observational data of LIGO-Virgo, and PBHs with masses 𝒪(10-6)M⊙ as potential explanation for the ultrashort-timescale microlensing events recorded in the OGLE data. Additionally, our proposed mechanism can generate PBHs with masses around 𝒪(10-13)M⊙, constituting roughly 99% of the dark matter. The density parameters of the produced GWs (ΩGW0) intersect with the sensitivity curves of GW detectors. Two cases of our model fall within the nano-Hz frequency regime. One of them satisfies the power-law scaling as ΩGW(f) ∼ f5-γ, with the γ = 3.51, which is consistent with the data of NANOGrav 15-year.
{"title":"Primordial black holes in SB SUSY Gauss-Bonnet inflation","authors":"A. Ashrafzadeh, M. Solbi, S. Heydari and K. Karami","doi":"10.1088/1475-7516/2025/01/025","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/025","url":null,"abstract":"Here, we explore the formation of primordial black holes (PBHs) within a scalar field inflationary model coupled to the Gauss-Bonnet (GB) term, incorporating the low-scale spontaneously broken supersymmetric (SB SUSY) potential. The coupling function amplifies the curvature perturbations, consequently leading to the formation of PBHs and detectable secondary gravitational waves (GWs). Through the adjustment of the model parameters, the inflaton can be decelerated during an ultra-slow-roll (USR) phase, thereby augmenting curvature perturbations. Beside the observational constraints, the swampland criteria are investigated. Our computations forecast the formation of PBHs with masses around 𝒪(10)M⊙, aligning with the observational data of LIGO-Virgo, and PBHs with masses 𝒪(10-6)M⊙ as potential explanation for the ultrashort-timescale microlensing events recorded in the OGLE data. Additionally, our proposed mechanism can generate PBHs with masses around 𝒪(10-13)M⊙, constituting roughly 99% of the dark matter. The density parameters of the produced GWs (ΩGW0) intersect with the sensitivity curves of GW detectors. Two cases of our model fall within the nano-Hz frequency regime. One of them satisfies the power-law scaling as ΩGW(f) ∼ f5-γ, with the γ = 3.51, which is consistent with the data of NANOGrav 15-year.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"82 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936719","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 : 2025-01-09DOI: 10.1088/1475-7516/2025/01/027
Jean-Luc Lehners and Jerome Quintin
Theoretical considerations motivate us to consider vacuum energy to be able to decay and to assume that the spatial geometry of the universe is closed. Combining both aspects leads to the possibility that the universe, or certain regions thereof, can collapse and subsequently undergo a curvature bounce. This may have occurred in the very early universe, in a pre-inflationary phase. We discuss the construction of the corresponding no-boundary instantons and show that they indeed reproduce a bouncing history of the universe, interestingly with a small and potentially observable departure from classicality during the contracting phase. Such an early bouncing history receives a large weighting and provides competition for a more standard inflationary branch of the wave function. Curvature bounces may also occur in the future. We discuss the conditions under which they may take place, allowing for density fluctuations in the matter distribution in the universe. Overall, we find that curvature bounces require a delicate combination of matter content and initial conditions to occur, though with significant consequences if these conditions are met.
{"title":"Delicate curvature bounces in the no-boundary wave function and in the late universe","authors":"Jean-Luc Lehners and Jerome Quintin","doi":"10.1088/1475-7516/2025/01/027","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/027","url":null,"abstract":"Theoretical considerations motivate us to consider vacuum energy to be able to decay and to assume that the spatial geometry of the universe is closed. Combining both aspects leads to the possibility that the universe, or certain regions thereof, can collapse and subsequently undergo a curvature bounce. This may have occurred in the very early universe, in a pre-inflationary phase. We discuss the construction of the corresponding no-boundary instantons and show that they indeed reproduce a bouncing history of the universe, interestingly with a small and potentially observable departure from classicality during the contracting phase. Such an early bouncing history receives a large weighting and provides competition for a more standard inflationary branch of the wave function. Curvature bounces may also occur in the future. We discuss the conditions under which they may take place, allowing for density fluctuations in the matter distribution in the universe. Overall, we find that curvature bounces require a delicate combination of matter content and initial conditions to occur, though with significant consequences if these conditions are met.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"39 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936721","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 : 2025-01-09DOI: 10.1088/1475-7516/2025/01/033
Raphaël Kou and Antony Lewis
One approach to reconciling local measurements of a high expansion rate with observations of acoustic oscillations in the CMB and galaxy clustering (the “Hubble tension”) is to introduce additional contributions to the ΛCDM model that are relevant before recombination. While numerous possibilities exist, none are currently well-motivated or preferred by data. However, future CMB experiments, which will measure acoustic peaks to much smaller scales and resolve polarization signals with higher signal-to-noise ratio over large sky areas, should detect almost any such modification at high significance. We propose a method to capture most relevant possible deviations from ΛCDM due to additional non-interacting components, while remaining sufficiently constraining to enable detection across various scenarios. The phenomenological model uses a fluid model with four parameters governing additional density contributions that peak at different redshifts, and two sound speed parameters. We forecast possible constraints with Simons Observatory, explore parameter degeneracies that arise in ΛCDM, and demonstrate that this method could detect a range of specific models. Which of the new parameters gets excited can give hints about the nature of any new physics, while the generality of the model allows for testing with future data in a way that should not be plagued by a posteriori choices and would reduce publication bias. When testing our model with Planck data, we find good consistency with the ΛCDM model, but the data also allows for a large Hubble parameter, especially if the sound speed of an additional component is not too different from that of radiation. The analysis with Planck data reveals significant volume effects, requiring careful interpretation of results. We demonstrate that Simons Observatory data will mitigate these volume effects, so that any indicated solution to the Hubble tension using our model cannot be mimicked by volume effects alone, given the significance of the tension.
{"title":"A flexible parameterization to test early physics solutions to the Hubble tension with future CMB data","authors":"Raphaël Kou and Antony Lewis","doi":"10.1088/1475-7516/2025/01/033","DOIUrl":"https://doi.org/10.1088/1475-7516/2025/01/033","url":null,"abstract":"One approach to reconciling local measurements of a high expansion rate with observations of acoustic oscillations in the CMB and galaxy clustering (the “Hubble tension”) is to introduce additional contributions to the ΛCDM model that are relevant before recombination. While numerous possibilities exist, none are currently well-motivated or preferred by data. However, future CMB experiments, which will measure acoustic peaks to much smaller scales and resolve polarization signals with higher signal-to-noise ratio over large sky areas, should detect almost any such modification at high significance. We propose a method to capture most relevant possible deviations from ΛCDM due to additional non-interacting components, while remaining sufficiently constraining to enable detection across various scenarios. The phenomenological model uses a fluid model with four parameters governing additional density contributions that peak at different redshifts, and two sound speed parameters. We forecast possible constraints with Simons Observatory, explore parameter degeneracies that arise in ΛCDM, and demonstrate that this method could detect a range of specific models. Which of the new parameters gets excited can give hints about the nature of any new physics, while the generality of the model allows for testing with future data in a way that should not be plagued by a posteriori choices and would reduce publication bias. When testing our model with Planck data, we find good consistency with the ΛCDM model, but the data also allows for a large Hubble parameter, especially if the sound speed of an additional component is not too different from that of radiation. The analysis with Planck data reveals significant volume effects, requiring careful interpretation of results. We demonstrate that Simons Observatory data will mitigate these volume effects, so that any indicated solution to the Hubble tension using our model cannot be mimicked by volume effects alone, given the significance of the tension.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"132 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936727","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：