Wed·Nov 25, 2020Wednesday·November 25, 2020

1. 01*

   Highly enhanced contributions of heavy Higgs bosons and new leptons to muon $g-2$ and prospects at future colliders

   Radovan Dermisek · Keith Hermanek · Navin McGinnis

   We show that in a two Higgs doublet model type-II extended by vectorlike leptons the contributions from heavy neutral and charged Higgs bosons to the anomalous magnetic moment of the muon simultaneously feature chiral enhancement from masses of new leptons and ${\tan }^2\beta$ enhancement from couplings of Higgs bosons. Assuming moderate values of new Yukawa couplings, not exceeding one, that can remain perturbative to very high energy scales, the measured value of muon $g-2$ can be explained within one standard deviation even with 6.5 TeV leptons or 20 TeV Higgs bosons. Allowing new couplings near the perturbativity limit, these mass ranges extend to 45 TeV for leptons and 190 TeV for Higgs bosons. In spite of the high scale of new physics this scenario can be completely probed at planned future colliders.

   hep-phPRL(2021)·38 citations
2. 02*

   Di-Higgs production as a probe of flavor changing neutral Yukawa couplings

   Shi-Ping He🇨🇳

   Top partners are well motivated in many new physics models. Usually, vector like quarks $T_{L,R}$ are introduced to avoid the quantum anomaly. It is crucial to probe their interactions with the standard model particles. However, flavor changing neutral couplings are always difficult to detect directly in the current and future experiments. In this paper, we will show how to constrain the flavor changing neutral Yukawa coupling $Tth$ through the di-Higgs production indirectly. We consider the simplified model including a pair of gauge singlet $T_{L,R}$. Under the perturbative unitarity and experimental constraints, we choose $m_T=400\mathrm{GeV},s_L=0.2$ and $m_T=800\mathrm{GeV},s_L=0.1$ as benchmark points. After the analysis of amplitude and evaluation of the numerical cross sections, we find that the present constraints from di-Higgs production have already surpassed the unitarity bound because of the $(y_{L,R}^{tT}{)}^4$ behavior. For the case of $m_T=400\mathrm{GeV}$ and $s_L=0.2$, $\mathrm{Re}{y}_{L,R}^{tT}$ and $\mathrm{Im}{y}_{L,R}^{tT}$ can be bounded optimally in the range $(-0.4,0.4)$ at HL-LHC with $2\sigma$ CL. For the case of $m_T=800\mathrm{GeV}$ and $s_L=0.1$, $\mathrm{Re}{y}_{L,R}^{tT}$ and $\mathrm{Im}{y}_{L,R}^{tT}$ can be bounded optimally in the range $(-0.5,0.5)$ at HL-LHC with $2\sigma$ CL. The anomalous triple Higgs coupling ${\delta }_{hhh}$ can also affect the constraints on $y_{L,R}^{tT}$. Finally, we find that the top quark electric dipole moment can give stronger bounds of $y_{L,R}^{tT}$ in the off-axis regions for some scenarios.

   hep-phhep-exCPC(2021)·3 citations
3. 03*

   Light Higgsinos for electroweak naturalness in mirage-mediated high-scale supersymmetry

   Kwang Sik Jeong🇰🇷 · Chan Beom Park🇰🇷

   Mirage mediation realized in the Kachru-Kallosh-Linde-Trivedi (KKLT) flux compactification can naturally suppress the up-type Higgs soft mass at low energy scales. As a result, compared to the conventional scenarios, the degree of electroweak fine-tuning can be reduced further up to by a loop factor if the Higgsinos are much lighter than the heavy Higgs doublet. Interestingly, this feature holds even in high-scale supersymmetry as long as the gauge coupling unification, which is required as a prerequisite for mirage mediation, accommodates such light Higgsinos. Under the experimental constraints on the observed Higgs boson, it turns out that mirage mediation can exhibit low electroweak fine-tuning better than a few percent for stops between about 2 and 6 TeV, i.e., at the same level as in the weak scale supersymmetry, if the Higgsinos are around or below a few hundred GeV.

   hep-phPRD(2021)·3 citations
4. 04*

   Quantum corrections to slow-roll inflation: scalar and tensor modes

   Jens O. Andersen🇳🇴 · Magdalena Eriksson🇳🇴 · Anders Tranberg🇳🇴

   Inflation is often described through the dynamics of a scalar field, slow-rolling in a suitable potential. Ultimately, this inflaton must be identified as the expectation value of a quantum field, evolving in a quantum effective potential. The shape of this potential is determined by the underlying tree-level potential, dressed by quantum corrections from the scalar field itself and the metric perturbations. Following [1], we compute the effective scalar field equations and the corrected Friedmann equations to quadratic order in both scalar field, scalar metric and tensor perturbations. We identify the quantum corrections from different sources at leading order in slow-roll, and estimate their magnitude in benchmark models of inflation. We comment on the implications of non-minimal coupling to gravity in this context.

   hep-phgr-qcJHEP(2021)·0 citations
5. 05*

   Short-distance HLbL contributions to the muon g-2

   Johan Bijnens🇸🇪 · Nils Hermansson-Truedsson🇨🇭 · Laetitia Laub🇨🇭 · Antonio Rodriguez-Sanchez🇸🇪

   The current $3.7\sigma$ discrepancy between the Standard Model prediction and the experimental value of the muon anomalous magnetic moment could be a hint for the existence of new physics. The hadronic light-by-light contribution is one of the pieces requiring improved precision on the theory side, and an important step is to derive short-distance constraints for this quantity containing four electromagnetic currents. Here, we derive such short-distance constraints for three large photon loop virtualities and the external fourth photon in the static limit. The static photon is considered as a background field and we construct a systematic operator product expansion in the presence of this field. We show that the massless quark loop, i.e. the leading term, is numerically dominant over non-perturbative contributions up to next-to-next-to leading order, both those suppressed by quark masses and those that are not.

   hep-phNucl.Part.Phys.Proc.(2021)·3 citations
6. 06*

   Low energy phenomena of the lepton sector in an $A_4$ symmetry model with heavy inverse seesaw neutrinos

   T. Phong Nguyen🇻🇳 · T.T. Thuc🇻🇳 · D.T. Si🇻🇳 · T.T.Hong🇻🇳 · L. T. Hue🇻🇳

   An extension of the two Higgs doublet model including inverse seesaw neutrinos and neutral Higgs bosons was constructed based on the $A_4$ symmetry in order to explain the recent neutrino oscillation data. This model can distinguish two well-known normal and inverted order schemes of neutrino data once both the effective masses $m_{\beta }$ in tritium beta decays and $⟨m⟩$ in the neutrinoless double beta decay are observed. The lepton flavor violating decays of the charged leptons $e_b\to e_a\gamma$, $\mu \to 3e$, the Standard model-like Higgs boson decays $h\to e_b{e}_a$, and the $\mu$-e conversions in some nuclei are generated from loop corrections. The experimental data of the branching ratio Br$(\mu \to e\gamma ,3e)$ predict that the upper bounds of Br$(\tau \to \mu \gamma ,e\gamma )$ and Br$(h\to e_a{e}_b)$ are much smaller than the planned experimental sensitivities. In contrast, the $\mu$-e conversions are the promising signals for experiments.

   hep-phPTEP(2022)·19 citations
7. 07*

   Gravitational wave spectra from oscillon formation after inflation

   Takashi Hiramatsu🇯🇵 · Evangelos I. Sfakianakis🇪🇸 · Masahide Yamaguchi🇯🇵

   We systematically investigate the preheating behavior of single field inflation with an oscillon-supporting potential. We compute the properties of the emitted gravitational waves (GWs) and the number density and characteristics of the produced oscillons. By performing numerical simulations for a variety of potential types, we divide the analyzed potentials in two families, each of them containing potentials with varying large- or small-field dependence. We find that the shape and amplitude of the emitted GW spectrum have a universal feature, with the peak around the physical wavenumber $k/a\sim m$ at the inflaton oscillation period, irrespective of the exact potential shape. This can be used as a smoking-gun for deducing the existence of a violent preheating phase and possible oscillon formation after inflation. Despite this apparent universality, we find differences in the shape of the emitted GW spectra between the two potential families, leading to discriminating features between them. In particular, all potentials show the emergence of a two-peak structure in the GW spectrum, arising at the time of oscillon formation. However, potentials exhibiting efficient parametric resonance tend to smear out this structure and by the end of the simulation the GW spectrum exhibits a single broad peak. We further compute the properties of the produced oscillons for each potential, finding differences in the number density and size distribution of stable oscillons and transient overdensities. We perform a linear fluctuation analysis and use Floquet charts to relate the results of our simulations to the structure of parametric resonance. We find that the growth rate of scalar perturbations and the associated oscillon formation time are sensitive to the small-field potential shape while the macroscopic physical properties of oscillons (e.g. total number) depend on the large-field potential shape.

   hep-phastro-ph.COhep-thJHEP(2021)·52 citations
8. 08*

   Consideration of a loop decay of dark matter particle into electron-positron from point of view of possible FSR suppression

   K.M. Belotsky🇷🇺 · A.Kh. Kamaletdinov🇷🇺

   Cosmic positron anomaly is still not explained. Explanation with dark matter (DM) decay or annihilation is one of the main attempts to do it. But they suffer with shortcoming as overproduction of induced gamma-radiation which contradict to cosmic gamma-background. Final state radiation (FSR) in such processes is supposed under standard conditions (by default) to have the basic contribution in it. Our group elaborates possibility to evade this problem in different ways. Here we continue one of them connected with possibility of suppression of FSR due to specifics of Lagrangian describing DM particle decay. Loop through two new spinors and scalar is considered. Effect of FSR suppression is found to be existing but at the very low level in the considered case.

   hep-phastro-ph.GAastro-ph.HE2 citations
9. 09*

   Particle Production from Oscillating Scalar Field and Consistency of Boltzmann Equation

   Takeo Moroi🇯🇵 · Wen Yin🇯🇵

   Boltzmann equation plays important roles in particle cosmology in studying the evolution of distribution functions (also called as occupation numbers) of various particles. For the case of the decay of a scalar condensation $\varphi$ into a pair of scalar particles (called $\chi$), we point out that the system may not be well described by the Boltzmann equation when the occupation number of $\chi$ becomes large even in the so-called narrow resonance regime. We study the particle production including the possible enhancement due to a large occupation number of the final state particle, known as the stimulated emission or the parametric resonance. Based on the quantum field theory (QFT), we derive a set of equations which directly govern the evolution of the distribution function of $\chi$. Comparing the results of the QFT calculation and those from the Boltzmann equation, we find non-agreements in some cases. In particular, in the expanding Universe, the occupation number of $\chi$ based on the QFT may differ by many orders of magnitude from that from the Boltzmann equation. We also discuss a possible relation between the evolution equations based on the QFT and the Boltzmann equation.

   hep-phastro-ph.COgr-qchep-thJHEP(2021)·42 citations
10. 10*

    Dark Matter Detection, Standard Model Parameters, and Intermediate Scale Supersymmetry

    David Dunsky🇺🇸 · Lawrence J. Hall🇺🇸 · Keisuke Harigaya🇺🇸

    The vanishing of the Higgs quartic coupling at a high energy scale may be explained by Intermediate Scale Supersymmetry, where supersymmetry breaks at $(10^9$-$10^{12})$ GeV. The possible range of supersymmetry breaking scales can be narrowed down by precise measurements of the top quark mass and the strong coupling constant. On the other hand, nuclear recoil experiments can probe Higgsino or sneutrino dark matter up to a mass of $10^{12}$ GeV. We derive the correlation between the dark matter mass and precision measurements of standard model parameters, including supersymmetric threshold corrections. The dark matter mass is bounded from above as a function of the top quark mass and the strong coupling constant. The top quark mass and the strong coupling constant are bounded from above and below respectively for a given dark matter mass. We also discuss how the observed dark matter abundance can be explained by freeze-out or freeze-in during a matter-dominated era after inflation, with the inflaton condensate being dissipated by thermal effects.

    hep-phJHEP(2021)·7 citations
11. 11*

    Minima of Classically Scale-Invariant Potentials

    Kristjan Kannike🇪🇪 · Kaius Loos🇪🇪 · Luca Marzola🇪🇪

    We propose a new formalism to analyse the extremum structure of scale-invariant effective potentials. The problem is stated in a compact matrix form, used to derive general expressions for the stationary point equation and the mass matrix of a multi-field RG-improved effective potential. Our method improves on (but is not limited to) the Gildener-Weinberg approximation and identifies a set of conditions that signal the presence of a radiative minimum. When the conditions are satisfied at different scales, or in different subspaces of the field space, the effective potential has more than one radiative minimum. We illustrate the method through simple examples and study in detail a Standard-Model-like scenario where the potential admits two radiative minima. Whereas we mostly concentrate on biquadratic potentials, our results carry over to the general case by using tensor algebra.

    hep-phJHEP(2021)·16 citations
12. 12*

    Virtual corrections to $gg\to ZH$ in the high-energy and large-$m_t$ limits

    Joshua Davies🇬🇧 · Go Mishima🇯🇵 · Matthias Steinhauser🇩🇪

    We compute the next-to-leading order virtual corrections to the partonic cross-section of the process $gg\to ZH$, in the high-energy and large-$m_t$ limits. We use Padé approximants to increase the radius of convergence of the high-energy expansion in $m_t^2/s$, $m_t^2/t$ and $m_t^2/u$ and show that precise results can be obtained down to energies which are fairly close to the top quark pair threshold. We present results both for the form factors and the next-to-leading order virtual cross-section.

    hep-phJHEP(2021)·45 citations
13. 13*

    Uncertainties in QE and RES events at LBNF due to hadronic production in FSI

    Ritu Devi🇮🇳 · Jaydip Singh🇮🇳 · Baba Potukuchi🇮🇳

    To achieve appropriate interaction rates in recent neutrino oscillation studies, high atomic number nuclear targets were utilized. Because of the nuclear effects in the experimental observable, the utilization of these complicated targets produced systematic uncertainties that needed to be assessed accurately to constrain the discovery. We made an effort to calculate the nuclear effects in the Ar and H targets, which are intended to be employed at the DUNE distant and near detectors, respectively, through our simulation effort. The DUNE flux is peaking around 2.5 GeV and CCRES is the dominant process at this energy. So, this work will be focused only on the CCQE and CCRES interactions and the simulations will be done using two different neutrino event generators. We reported the ratio of the oscillation probability (P(Ar)/P(H) as a function of reconstructed neutrino energy for CCRES channels to quantify the systematic errors in the observables.

    hep-phBraz.J.Phys.(2022)·3 citations
14. 14*

    Toward Quantum Simulations of ${\mathbb{Z}}_2$ Gauge Theory Without State Preparation

    Erik J. Gustafson🇺🇸 · Henry Lamm🇺🇸

    Preparing strongly-coupled particle states on quantum computers requires large resources. In this work, we show how classical sampling coupled with projection operators can be used to compute Minkowski matrix elements without explicitly preparing these states on the quantum computer. We demonstrate this for the 2+1d ${\mathbb{Z}}_2$ lattice gauge theory on small lattices with a quantum simulator.

    ↳ hep-lathep-phhep-thquant-phPRD(2021)·58 citations
15. 15*

    Gravitational effects on oscillon lifetimes

    Hong-Yi Zhang🇺🇸

    Many scalar field theories with attractive self-interactions support exceptionally long-lived, spatially localized and time-periodic field configurations called oscillons. A detailed study of their longevity is important for understanding their applications in cosmology. In this paper, we study gravitational effects on the decay rate and lifetime of dense oscillons, where self-interactions are more or at least equally important compared with gravitational interactions. As examples, we consider the $\alpha$-attractor T-model of inflation and the axion monodromy model, where the potentials become flatter than quadratic at large field values beyond some characteristic field distance $F$ from the minimum. For oscillons with field amplitudes of $\mathcal{O}(F)$ and for $F\ll 0.1M_{\mathrm{pl}}$, we find that their evolution is almost identical to cases where gravity is ignored. For $F\sim 0.1M_{\mathrm{pl}}$, however, including gravitational interactions reduces the lifetime slightly.

    ↳ hep-thastro-ph.COhep-phnlin.PSJCAP(2021)·31 citations
16. 16*

    Topological violation of global symmetries in quantum gravity

    Kazuya Yonekura🇯🇵

    We discuss a topological reason why global symmetries are not conserved in quantum gravity, at least when the symmetry comes from compactification of a higher form symmetry. The mechanism is purely topological and does not require any explicit breaking term in the UV Lagrangian. Local current conservation does not imply global charge conservation in a sum over geometries in the path integral. We explicitly consider the shift symmetry of an axion-like field which originates from the compactification of a $p$-form gauge field. Our topological construction is motivated by the brane/black-brane correspondence, brane instantons, and an idea that virtual black branes of a simple kind may be realized by surgery on spacetime manifolds.

    ↳ hep-thgr-qchep-phJHEP(2021)·27 citations
17. 17*

    Detection of isotropic cosmic birefringence and its implications for axion-like particles including dark energy

    Tomohiro Fujita🇯🇵 · Kai Murai🇯🇵 · Hiromasa Nakatsuka🇯🇵 · Shinji Tsujikawa🇯🇵

    We investigate the possibility that axion-like particles (ALPs) with various potentials account for the isotropic birefringence recently reported by analyzing the Planck 2018 polarization data. For the quadratic and cosine potentials, we obtain lower bounds on the mass, coupling constant to photon $g$, abundance and equation of state of the ALP to produce the observed birefringence. Especially when the ALP is responsible for dark energy, it is possible to probe the tiny deviation of dark energy equation of state from $-1$ through the cosmic birefringence. We also explore ALPs working as early dark energy (EDE), which alleviates the Hubble tension problem. Since the other parameters are limited by the EDE requirements, we narrow down the ALP-photon coupling to $10^{-19}{\mathrm{GeV}}^{-1}\lesssim g\lesssim 10^{-16}{\mathrm{GeV}}^{-1}$ for the decay constant $f=M_{\mathrm{pl}}$. Therefore, the Hubble tension and the isotropic birefringence imply that $g$ is typically the order of $f^{-1}$, which is a non-trivial coincidence.

    ↳ astro-ph.COhep-phPRD(2021)·118 citations
18. 18*

    Inverting cosmic ray propagation by Convolutional Neural Networks

    Yue-Lin Sming Tsai🇨🇳 · Yi-Lun Chung🇹🇼 · Qiang Yuan🇨🇳 · Kingman Cheung🇹🇼

    We propose a machine learning method to investigate the propagation of cosmic rays based on the precisely measured spectra of the primary and secondary cosmic ray nuclei of Li, Be, B, C, and O from AMS-02, ACE, and Voyager-1. We train two convolutional neural networks. One network learns how to infer propagation and source parameters from the energy spectra of cosmic rays, and the other network, which is similar to the former, has the flexibility to learn from the data with added artificial fluctuations. Together with the simulated data generated by GALPROP, we find that both networks can properly invert the propagation process and infer the propagation and source parameters reasonably well. This approach can be much more efficient than the traditional Markov chain Monte Carlo fitting method for deriving the propagation parameters if users choose to update confidence intervals with new experimental data. Both of the trained networks are available at (https://github.com/alan200276/CR_ML).

    ↳ astro-ph.HEhep-phJCAP(2022)·5 citations
19. 19*

    QCD Phase Diagram by Holography

    Yi Yang🇹🇼 · Pei-Hung Yuan🇨🇳

    We explore QCD phase diagram by constructing a holographic QCD model using the Einstein-Maxwell-Scalar system. The chiral transition is investigated by adding a probe scalar and confinement transition is studied by adding a probe string into the system. By interpreting the black hole phase transition in the bulk spacetime as the quarkyonic transition in the dual QCD theory and introducing the bypass mechanism for deconfinement transition, we give an explanation why chiral symmetry breaking and deconfinement transition lines coincide with each other despite their different physical origins.

    ↳ hep-thhep-phPLB(2022)·13 citations
20. 20*

    Universal profiles for radio searches of dark matter in dwarf galaxies

    Martin Vollmann🇩🇪

    The phenomenology of diffuse radio emission from Dark Matter annihilation or decay in dwarf spheroidal galaxies is examined. We introduce (in the context of cosmic-ray physics) a novel strategy for the computation of the relevant synchrotron signals. In particular, we identify various regimes where, in analogy to prompt gamma rays, the diffuse radio signal from dark matter annihilation/decay can be expressed as the multiplication of a "halo" times a spectral function. These functions are computed here for the first time for a number of benchmark cases. Furthermore, we find parameter regions in which the emissivity can be well approximated by a universal function ~ sin(kr)/r, where r is the galacto-centric distance. Our theoretical setup differs from previous work in that, instead of employing a method-of-images strategy, we consider a Fourier-mode expansion of the relevant Green's functions. With this strategy, exact results can be obtained with very low computational cost and for generic dark matter models. In particular, O(10- 100) Fourier modes can be easily incorporated into the computations in order to probe the smallest scales of the problem. We also propose a new strategy to search for dark matter using radio observations of dwarf galaxies that is (1) easy to implement and (2) free of the otherwise large degeneracies in the description of synchrotron signals from dark matter. Finally, we correct a mistake in a widely used Green's function formula in this context. We show that the original expression leads to systematically incorrect - and in some cases divergent - results in the regime where the characteristic time-scale for diffusion is smaller than that for energy losses.

    ↳ astro-ph.HEhep-phJCAP(2021)·16 citations
21. 21*

    Conundrums at Finite Density

    Rajiv V. Gavai🇩🇪

    Extending the successes of lattice quantum chromodynamics(QCD) at zero as well as nonzero temperatures to nonzero density is extremely desirable in view of the quest for the QCD phase diagram both theoretically and experimentally. It turns out though to give rise to some conundrums whose resolution may assist progress in this exciting but difficult area, and should therefore be sought actively.

    ↳ hep-lathep-phnucl-thActa Phys.Polon.Supp.(2021)·0 citations
22. 22*

    Scale setting the Möbius Domain Wall Fermion on gradient-flowed HISQ action using the omega baryon mass and the gradient-flow scales $t_0$ and $w_0$

    Nolan Miller🇺🇸 · Logan C Carpenter🇺🇸 · Evan Berkowitz🇺🇸 · Chia Cheng Chang🇯🇵 · Ben Hörz🇺🇸 · Dean Howarth🇺🇸 · Henry Monge-Camacho🇺🇸 · Enrico Rinaldi🇯🇵 · David A. Brantley🇺🇸 · Christopher Körber🇺🇸 · Chris Bouchard🇬🇧 · M.A. Clark🇺🇸 and 5 other authors

    We report on a sub-percent scale determination using the omega baryon mass and gradient-flow methods. The calculations are performed on 22 ensembles of $N_f=2+1+1$ highly improved, rooted staggered sea-quark configurations generated by the MILC and CalLat Collaborations. The valence quark action used is Möbius Domain-Wall fermions solved on these configurations after a gradient-flow smearing is applied with a flowtime of $t_{\mathrm{gf}}=1$ in lattice units. The ensembles span four lattice spacings in the range $0.06\lesssim a\lesssim 0.15$ fm, six pion masses in the range $130\lesssim m_{\pi }\lesssim 400$ MeV and multiple lattice volumes. On each ensemble, the gradient-flow scales $t_0/a^2$ and $w_0/a$ and the omega baryon mass $a{m}_{\Omega }$ are computed. The dimensionless product of these quantities is then extrapolated to the continuum and infinite volume limits and interpolated to the physical light, strange and charm quark mass point in the isospin limit, resulting in the determination of $\sqrt{t_0}=0.1422(14)$ fm and $w_0=0.1709(11)$ fm with all sources of statistical and systematic uncertainty accounted for. The dominant uncertainty in this result is the stochastic uncertainty, providing a clear path for a few-per-mille uncertainty, as recently obtained by the Budapest-Marseille-Wuppertal Collaboration.

    ↳ hep-lathep-phnucl-thPRD(2021)·40 citations
23. 23*

    Inhomogeneous initial conditions for inflation: A wibbly-wobbly timey-wimey path to salvation

    Cristian Joana🇧🇪 · Sebastien Clesse🇧🇪

    We use the 3+1 formalism of numerical relativity to investigate the robustness of Starobinsky and Higgs inflation to inhomogeneous initial conditions, in the form of either field gradient or kinetic energy density. Sub-Hubble and Hubble-sized fluctuations generically lead to inflation after an oscillatory phase between gradient and kinetic energies. Hubble-sized inhomogeneities also produce contracting regions that may end up forming primordial black holes, subsequently diluted by inflation. We analyse the dynamics of the preinflation era and the generation of vector and tensor fluctuations. Our analysis further supports the robustness of inflation to any size of inhomogeneity, in the field, velocity or equation of state. At large field values, the preinflation dynamics only marginally depends on the field potential and it is expected that such behaviour is universal and applies to any inflation potential of plateau-type, favoured by CMB observations after Planck.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2021)·47 citations
24. 24*

    Prospects of Future CMB Anisotropy Probes for Primordial Black Holes

    Junsong Cang🇨🇳 · Yu Gao🇨🇳 · Yinzhe Ma🇿🇦

    Cascade of particles injected as Hawking Radiation from Primordial Black Holes (PBH) can potentially change the cosmic recombination history by ionizing and heating the intergalactic medium, which results in altering the anisotropy spectra of the Cosmic Microwave Background (CMB). In this paper, we study the expected sensitivity of several future CMB experiments in constraining the abundance of PBHs distributed in $10^{15}\sim 10^{17}$ g mass window according to four mass functions: the monochromatic, log-normal, power-law and critical collapse models. Our result shows that future experiments, such as CMB-S4 and PICO, can improve current {\it{Planck}} bounds by about two orders of magnitudes. All regions in PBH parameter space that are allowed by current CMB data, including monochromatically distributed PBHs with mass heavier than $4\times 10^{16}$ grams, can be excluded by upcoming missions with high significance.

    ↳ astro-ph.COhep-phJCAP(2021)·28 citations
25. 25*

    The Effective Field Theory and Perturbative Analysis for Log-Density Fields

    Henrique Rubira🇩🇪 · Rodrigo Voivodic🇧🇷

    A logarithm transformation over the matter overdensity field $\delta$ brings information from the bispectrum and higher-order n-point functions to the power spectrum. We calculate the power spectrum for the log-transformed field $A$ at one, two and three loops using perturbation theory (PT). We compare the results to simulated data and give evidence that the PT series is asymptotic already on large scales, where the $k$ modes no longer decouple. This motivates us to build an alternative perturbative series for the log-transformed field that is not constructed on top of perturbations of $\delta$ but directly over the equations of motion for $A$ itself. This new approach converges faster and better reproduces the large scales at low $z$. We then show that the large-scale behaviour for the log-transformed field power spectrum can be captured by a small number of free parameters. Finally, we add the counter-terms expected within the effective field theory framework and show that the theoretical model, together with the IR-resummation procedure, agrees with the measured spectrum with percent precision until $k\simeq 0.38$ Mpc${}^{-1}$h at $z=0$. It indicates that the non-linear transformation indeed linearizes the density field and, in principle, allows us to access information contained on smaller scales.

    ↳ astro-ph.COgr-qchep-phJCAP(2021)·12 citations
26. 26*

    Dark Matter in the Time of Primordial Black Holes

    Nicolás Bernal🇨🇴 · Óscar Zapata🇨🇴

    Hawking evaporation of primordial black holes (PBH) with masses ranging from $\sim 10^{-1}$ to $\sim 10^9$ g can generate the whole observed dark matter (DM) relic density. However, a second DM production mechanism, like freeze-out or freeze-in, could have also been active in the early universe. Here we study the interplay of these mechanisms, focusing on the scenario where PBHs dominate the energy density of the universe, leading to a nonstandard cosmological era. For concreteness, we use the singlet scalar DM model as an example for this analysis.

    ↳ astro-ph.COhep-phJCAP(2021)·104 citations
27. 27*

    Flavor-specific Interaction Favors Strong Neutrino Self-coupling in the Early Universe

    Anirban Das (SLAC)🇺🇸 · Subhajit Ghosh (Notre Dame U. and TIFR)🇺🇸

    Flavor-universal neutrino self-interaction has been shown to ease the tension between the values of the Hubble constant measured from early and late Universe data. We introduce a self-interaction structure that is flavor-specific in the three active neutrino framework. This is motivated by the stringent constraints on new secret interactions among electron and muon neutrinos from several laboratory experiments. Our study indicates the presence of a strongly interaction mode which implies a late-decoupling of the neutrinos just prior to matter radiation equality. Using the degeneracy of the coupling strength with other cosmological parameters, we explain the origin of this new mode as a result of better fit to certain features in the CMB data. We find that if only one or two of the three active neutrino flavors are interacting, then the statistical significance of the strongly-interacting neutrino mode increases substantially relative to the flavor-universal scenario. However, the central value of the coupling strength for this interaction mode does not change by any appreciable amount in the flavor-specific cases. We also briefly analyze a scenario with more than three neutrino species of which only one is self-interacting. In none of the cases, we find a large enough Hubble constant that could resolve the so-called Hubble tension.

    ↳ astro-ph.COhep-phJCAP(2021)·94 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.