Fri·May 27, 2022Friday·May 27, 2022

1. 01*

   Oscillations of atomic energy levels induced by QCD axion dark matter

   Hyungjin Kim🇩🇪 · Gilad Perez🇮🇱

   Axion-gluon interaction induces quadratic couplings between the axion and the matter fields. We find that, if the axion is an ultralight dark matter field, it induces small oscillations of the mass of the hadrons as well as other nuclear quantities. As a result, atomic energy levels oscillate. We use currently available atomic spectroscopy data to constrain such axion-gluon coupling. We also project the sensitivities of future experiments, such as ones using molecular and nuclear clock transitions. We show that current and near-future experiments constrain a finely-tuned parameter space of axion models. These can compete with or dominate the already-existing constraints from oscillating neutron electric dipole moment and supernova bound, in addition to those expected from near future magnetometer-based experiments. We also briefly discuss the reach of accelerometers and interferometers.

   hep-phphysics.atom-phPRD(2024)·66 citations
2. 02*

   How many 1-loop neutrino mass models are there?

   Carolina Arbeláez🇨🇱 · Ricardo Cepedello🇩🇪 · Juan Carlos Helo🇨🇱 · Martin Hirsch🇪🇸 · Sergey Kovalenko🇨🇱

   It is well-known that at tree-level the d=5 Weinberg operator can be generated in exactly three different ways, the famous seesaw models. In this paper we study the related question of how many phenomenologically consistent 1-loop models one can construct at d=5. First, we discuss that there are two possible classes of 1-loop neutrino mass models, that allow avoiding stable charged relics: (i) Models with dark matter candidates and (ii) models with "exits". Here, we define "exits" as particles that can decay into standard model fields. Considering 1-loop models with new scalars and fermions, we find in the dark matter class a total of (113+205) models, while in the exit class we find (38+368) models. Here, 113 is the number of DM models, which require a stabilizing symmetry, while 205 is the number of models which contain a dark matter candidate, which maybe accidentally stable. In the exit class the 38 refers to models, for which one (or two) of the internal particles in the loop is a SM field, while the 368 models contain only fields beyond the SM (BSM) in the neutrino mass diagram. We then study the RGE evolution of the gauge couplings in all our 1-loop models. Many of the models in our list lead to Landau poles in some gauge coupling at rather low energies and there is exactly one model which unifies the gauge couplings at energies above $10^{15}$ GeV in a numerically acceptable way.

   hep-phJHEP(2022)·22 citations
3. 03*

   The Neutrinoless Double Beta Decay in the Colored Zee-Babu Model

   Shao-Long Chen🇨🇳 · Yu-Qi Xiao🇨🇳

   We study the neutrinoless double beta decay in the colored Zee-Babu model. We consider three cases of the colored Zee-Babu model with a leptoquark and a diquark introduced. The neutrino masses are generated at two-loop level, and the constraints given by tree-level flavor violation processes and muon anomalous magnetic moment $(g-2{)}_{\mu }$ have been considered. In our numerical analysis, we find that the standard light neutrino exchange contribution can be canceled by new physics contribution under certain assumption and condition, leading to a hidden neutrinoless double beta decay. The condition can be examined comprehensively by future complementary searches with different isotopes.

   hep-phNPB(2023)·2 citations
4. 04*

   Constraining pseudo-Dirac neutrinos from a galactic core-collapse supernova

   Manibrata Sen🇩🇪

   Neutrinos can be pseudo-Dirac in nature -- Majorana fermions behaving as Dirac fermions for all practical purposes. In such a scenario, active and sterile neutrinos are quasi-degenerate in mass, and hence oscillations between the two, due to their tiny mass-squared difference $(\delta m^2)$, can develop only over very long baselines. Under this hypothesis, we analyze the neutrino data from SN1987A, and find a mild preference for a non-zero mass-squared difference. The same data can also be used to exclude values of $\delta m^2\sim 10^{-20}{\mathrm{eV}}^2$ - the smallest constrained so far. We also discuss how next-generation experiments like the DUNE and Hyper-Kamiokande can probe this scenario for a future galactic supernova.

   hep-ph2 citations
5. 05*

   Double-charm tetraquark under the complex scaling method

   Jian-Bo Cheng🇨🇳 · Zi-Yang Lin🇨🇳 · Shi-Lin Zhu🇨🇳

   The LHCb Collaboration discovered a double-charm tetraquark $T_{cc}^{+}$ with a very small width. We investigate the $T_{cc}^{+}$ as a $D{D}^{\ast }$ molecule with $J^P=1^{+}$ in the framework of the one-boson-exchange potential model. The isospin breaking effect and $S-D$ wave coupling are taken into account carefully. We adopt the complex scaling method (CSM) to study the $D{D}^{\ast }$ system and obtain a quasibound state corresponding to the $T_{cc}^{+}$. Its binding energy relative to the $D^0{D}^{\ast +}$ and width are $-354$ keV and $61$ keV respectively. The isospin breaking effect is found to be enormous, and the $S-$wave $D^0{D}^{\ast +}$ and $D^{+}{D}^{\ast 0}$ components give dominant contributions with the probabilities of $72.1\%$ and $27.1\%$ respectively. In addition, we do not find any resonances in the $D{D}^{\ast }$ system. As a by-product, we study the $X(3872)$ as a $(D{\bar{D}}^{\ast }-D^{\ast }\bar{D})/\sqrt{2}$ molecule with $J^{PC}=1^{++}$. We also find a quasibound state corresponding to the $X(3872)$. Its binding energy relative to the $D^0{\bar{D}}^{\ast 0}$ threshold and width are $-111$ keV and $26$ keV respectively. The $S-$wave $(D^0{\bar{D}}^{\ast 0}-D^{\ast 0}{\bar{D}}^0)/\sqrt{2}$ component dominates this state with the probability of $92.7\%$.

   hep-phnucl-thPRD(2022)·39 citations
6. 06*

   Phonon modes of magnetic vortex lattices in finite isospin chiral perturbation theory

   Prabal Adhikari🇺🇸 · Elizabeth Leeser🇺🇸 · Jake Markowski🇺🇸

   We study phonon modes associated with magnetic vortex lattices of finite isospin chiral perturbation theory near the upper critical point by introducing quasimomentum fluctuations to the lattice and calculate dispersion relations associated with the optical and acoustic modes. We find that one of the acoustic modes is massless and that its energy for small transverse quasimomentum is quartic (due the presence of an isospin chemical potential), which is significantly softer than the "supersoft" (quadratic) massless mode of the Abelian Higgs Model (AHM). Due to the presence of derivative interactions, which is absent in the AHM, the speed of the longitudinal mode depends on both the isospin chemical potential and the external magnetic field. Our results suggest that the standard assumption of an ordered lattice in finite isospin QCD should be revisited and the existence of a disordered spaghetti phase of a vortex liquid or gas, should be considered.

   hep-phhep-thnucl-thMod.Phys.Lett.A(2023)·10 citations
7. 07*

   Ultraforward production of a charmed hadron plus a Higgs boson in unpolarized proton collisions

   Francesco Giovanni Celiberto🇮🇹 · Michael Fucilla🇮🇹 · Mohammed M.A. Mohammed🇮🇹 · Alessandro Papa🇮🇹

   We investigate the inclusive emission in unpolarized proton collisions of a charm-flavored hadron in association with a Higgs boson, featuring large transverse momenta and produced with a large rapidity distance. Taking advantage of a narrow timing coincidence between the ATLAS detector and the future FPF ones, we study the behavior of cross sections and azimuthal correlations for ultraforward rapidities of the detected hadron. We provide evidence that the hybrid high-energy and collinear factorization, encoding the BFKL resummation of large energy logarithms and supplemented by collinear densities and fragmentation functions, offers a fair description of this process and comes out as an important tool to deepen our understanding of strong interactions in ultraforward production regimes.

   hep-phPRD(2022)·53 citations
8. 08*

   Atom Interferometer Tests of Dark Matter

   Yufeng Du🇺🇸 · Clara Murgui🇺🇸 · Kris Pardo🇺🇸 · Yikun Wang🇺🇸 · Kathryn M. Zurek🇺🇸

   Direct detection experiments for dark matter are increasingly ruling out large parameter spaces. However, light dark matter models with particle masses $<$ GeV are still largely unconstrained. Here we examine a proposal to use atom interferometers to detect a light dark matter subcomponent at sub-GeV masses. We describe the decoherence and phase shifts caused by dark matter scattering off of one "arm" of an atom interferometer using a generalized dark matter direct detection framework. This allows us to consider multiple channels: nuclear recoils, hidden photon processes, and axion interactions. We apply this framework to several proposed atom interferometer experiments. Because atom interferometers are sensitive to extremely low momentum deposition and their coherent atoms may give them a boost in sensitivity, these experiments will be highly competitive and complementary to other direct detection methods. In particular, atom interferometers are uniquely able to probe a dark matter sub-component with $m_{\chi }\lesssim 10\mathrm{keV}$. We find that, for a mediator mass $m_{\varphi }=10^{-5}{m}_{\chi }$, future atom interferometers could close a gap in the existing constraints on nuclear recoils down to ${\bar{\sigma }}_n\sim 10^{-42}{\mathrm{cm}}^2$ for $m_{\chi }\sim 10^{-5}-10^{-1}\mathrm{MeV}$ dark matter masses.

   hep-phastro-ph.COquant-phPRD(2022)·37 citations
9. 09*

   Assessment of the Dimension-5 Seesaw Portal and Impact of Exotic Higgs Decays on Non-Pointing Photon Searches

   F. Delgado🇵🇪 · L. Duarte🇺🇾 · J. Jones-Perez🇵🇪 · C. Manrique-Chavil🇵🇪 · S. Peña🇵🇪

   The Dimension-5 Seesaw Portal is a Type-I Seesaw model extended by $d=5$ operators involving the sterile neutrino states, leading to new interactions between all neutrinos and the Standard Model neutral bosons. In this work we focus primarily on the implications of these new operators at the GeV-scale. In particular, we recalculate the heavy neutrino full decay width, up to three-body decays. We also review bounds on the dipole operator, and revisit LEP constraints on its coefficient. Finally, we turn to heavy neutrino pair production from Higgs decays, where the former are long-lived and disintegrate into a photon and a light neutrino. We probe this process by recasting two ATLAS searches for non-pointing photons, showing the expected event distribution in terms of arrival time $t_{\gamma }$ and pointing variable $|\Delta z_{\gamma }|$.

   hep-phJHEP(2022)·36 citations
10. 10*

    New Physics in $b\to s\mu \mu$: FCC-hh or a Muon Collider?

    Aleksandr Azatov🇮🇹 · Francesco Garosi🇮🇹 · Admir Greljo🇨🇭 · David Marzocca🇮🇹 · Jakub Salko🇨🇭 · Sokratis Trifinopoulos🇮🇹

    Rare flavour-changing neutral-current transitions $b\to s{\mu }^{+}{\mu }^{-}$ probe higher energy scales than what is directly accessible at the LHC. Therefore, the presence of new physics in such transitions, as suggested by the present-day LHCb anomalies, would have a major impact on the motivation and planning of future high-energy colliders. The two most prominent options currently debated are a proton-proton collider at 100 TeV (FCC-hh) and a multi-TeV muon collider (MuC). In this work, we compare the discovery prospects at these colliders on benchmark new physics models indirectly detectable in $b\to s{\mu }^{+}{\mu }^{-}$ decays but beyond the reach of the high-$p_T$ searches at the HL-LHC. We consider a comprehensive set of scenarios: semileptonic contact interactions, $Z^{\prime }$ from a gauged $U(1{)}_{B_3-L_{\mu }}$ and $U(1{)}_{L_{\mu }-L_{\tau }}$, the scalar leptoquark $S_3$, and the vector leptoquark $U_1$. We find that a 3 TeV MuC has a sensitivity reach comparable to the one of the FCC-hh. However, for a heavy enough mediator, the new physics effects at a 3 TeV MuC are only observed indirectly via deviations in the highest energy bin, while the FCC-hh has a greater potential for the discovery of a resonance. Finally, to completely cover the parameter space suggested by the $bs\mu \mu$ anomalies, among the proposed future colliders, only a MuC of 10 TeV (or higher) can meet the challenge.

    hep-phhep-exJHEP(2022)·51 citations
11. 11*

    Generating Non-topological Solitons Via Thermal Corrections: Higgs Balls

    Lauren Pearce🇺🇸 · Graham White🇯🇵 · Alexander Kusenko🇺🇸

    Scalar fields which carry charge can generally form non-topoligical solitons (Q-balls), if the energy in the extended configuration is less than the energy of an equivalent number of free quanta. For global Q-balls, such solitons exist whenever the potential grows slower than quadratically. We show that even in the absence of attractive interactions, finite temperature corrections can generate Q-ball solutions, as the coefficient of cubic corrections is generally negative. As an illustration of this, we consider the possibility of constructing Q-balls using the Higgs field. We first show that the finite temperature corrections would enable the existence of Higgs balls if the Standard Model symmetry was ungauged. We then show that Higgs self-interactions mediated by the Standard Model gauge bosons are sufficient to prevent the existence of these states in the actual Standard Model, but they can be present in a variety of extensions.

    hep-phJHEP(2022)·8 citations
12. 12*

    The generation of narrow ultrarelativistic beams of positrons (electrons) in the process of resonant photogeneration of pairs on nuclei in a strong electromagnetic field

    S. P. Roshchupkin🇷🇺 · S. S. Starodub🇺🇦

    The generation of narrow beams of high-energy positrons (electrons) in the process of resonant photogeneration of ultrarelativistic electron-positron pairs by high-energy gamma quanta in the field of the nucleus and a strong electromagnetic wave is theoretically predicted. It is shown that if the energy of the initial gamma quanta significantly exceeds the characteristic energy of the process, then ultrarelativistic positrons (for channel A) or electrons (for channel B) are emitted with energies very close to the energy of gamma quanta. Moreover, the resonant differential cross-section of such processes can exceed the corresponding differential cross-section without an external field by thirteen orders of magnitude. This effect makes it possible to obtain narrow beams of ultrarelativistic positrons (electrons) in strong electromagnetic fields with high probability.

    hep-phLaser Phys.Lett.(2022)·4 citations
13. 13*

    What is the fate of Hawking evaporation in gravity theories with higher curvature terms?

    Fabrizio Corelli🇮🇹 · Marina De Amicis🇮🇹 · Taishi Ikeda🇮🇹 · Paolo Pani🇮🇹

    During the final stages of black hole evaporation, ultraviolet deviations from General Relativity eventually become dramatic, potentially affecting the end-state. We explore this problem by performing nonlinear simulations of wave packets in Einstein-dilaton-Gauss-Bonnet gravity, the only gravity theory with quadratic curvature terms which can be studied at fully nonperturbative level. Black holes in this theory have a minimum mass but also a nonvanishing temperature. This poses a puzzle concerning the final fate of Hawking evaporation in the presence of high-curvature nonperturbative effects. By simulating the mass loss induced by evaporation at the classical level using an auxiliary phantom field, we study the nonlinear evolution of black holes past the minimum mass. We observe a runaway shrink of the horizon (a nonperturbative effect forbidden in General Relativity) which eventually unveils a high-curvature elliptic region. While this might hint to the formation of a naked singularity (and hence to a violation of the weak cosmic censorship) or of a pathological spacetime region, a different numerical formulation of the initial-value problem in this theory might be required to rule out other possibilities, including the transition from the critical black hole to a stable horizonless remnant. Our study is relevant in the context of the information-loss paradox, dark-matter remnants, and for constraints on microscopic primordial black holes.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRL(2023)·27 citations
14. 14*

    Nonperturbative gedanken experiments in Einstein-dilaton-Gauss-Bonnet gravity: nonlinear transitions and tests of the cosmic censorship beyond General Relativity

    Fabrizio Corelli🇮🇹 · Marina De Amicis🇮🇹 · Taishi Ikeda🇮🇹 · Paolo Pani🇮🇹

    As the only gravity theory with quadratic curvature terms and second-order field equations, Einstein-dilaton-Gauss-Bonnet gravity is a natural testbed to probe the high-curvature regime beyond General Relativity in a fully nonperturbative way. Due to nonperturbative effects of the dilatonic coupling, black holes in this theory have a minimum mass which separates a stable branch from an unstable one. The minimum mass solution is a double point in the phase diagram of the theory, wherein the critical black hole and a wormhole solution coexist. We perform extensive nonlinear simulations of the spherical collapse onto black holes with scalar hair in this theory, especially focusing on the region near the minimum mass. We study the nonlinear transition from the unstable to the stable branch and assess the nonlinear stability of the latter. Furthermore, motivated by modeling the mass loss induced by Hawking radiation near the minimum mass at the classical level, we study the collapse of a phantom field onto the black hole. When the black-hole mass decreases past the critical value, the apparent horizon shrinks significantly, eventually unveiling a high-curvature elliptic region. We argue that evaporation in this theory is bound to either violate the weak cosmic censorship or produce horizonless remnants. Addressing the end-state might require a different evolution scheme.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2023)·33 citations
15. 15*

    Constraining annihilating dark matter by radio continuum spectrum of the Large Magellanic Cloud

    Man Ho Chan🇨🇳 · Chak Man Lee🇨🇳

    Recent radio observations have obtained stringent constraints for annihilating dark matter. In this article, we use the radio continuum spectral data of the Large Magellanic Cloud (LMC) to analyze the dark matter annihilation signals. We have discovered a slightly positive signal of dark matter annihilation with a $1.5\sigma$ statistical significance. The overall best-fit dark matter mass is $m_{\mathrm{DM}}\approx 90$ GeV, annihilating via $b\bar{b}$ channel. We have also constrained the $3\sigma$ lower limits of dark matter mass with the standard thermal dark matter annihilation cross section for the $e^{+}{e}^{-}$, ${\mu }^{+}{\mu }^{-}$, ${\tau }^{+}{\tau }^{-}$ and $b\bar{b}$ channels.

    ↳ astro-ph.GAastro-ph.HEhep-phApJ(2022)·8 citations
16. 16*

    Shapes of non-Gaussianity in warm inflation

    Mehrdad Mirbabayi🇮🇹 · Andrei Gruzinov🇺🇸

    Sphaleron heating has been recently proposed as a mechanism to realize warm inflation when inflaton is an axion coupled to pure Yang-Mills. As a result of heating, there is a friction coefficient $\gamma \propto T^3$ in the equation of motion for the inflaton, and a thermal contribution to cosmological fluctuations. Without the knowledge of the inflaton potential, non-Gaussianity is the most promising way of searching for the signatures of this model. Building on an earlier work by Bastero-Gil, Berera, Moss and Ramos, we compute the scalar three-point correlation function and point out some distinct features in the squeezed and folded limits. As a detection strategy, we show that the combination of the equilateral template and one new template has a large overlap with the shape of non-Gaussianity over the range $0.01\le \gamma /H\le 1000$, and in this range $0.7<|f_{\mathrm{NL}}|<50$.

    ↳ astro-ph.COhep-phhep-thJCAP(2023)·42 citations
17. 17*

    UV completion of extradimensional Yang-Mills theory for Gauge-Higgs unification

    Álvaro Pastor-Gutiérrez🇩🇪 · Masatoshi Yamada🇩🇪

    The $SU(N)$ Yang-Mills theory in ${\mathbb{R}}^4\times S^1$ spacetime is studied as a simple toy model of Gauge-Higgs unification. The theory is perturbatively nonrenormalizable but could be formulated as an asymptotically safe theory, namely a nonperturbatively renormalizable theory. We study the fixed point structure of the Yang-Mills theory in ${\mathbb{R}}^4\times S^1$ by using the functional renormalization group in the background field approximation. We derive the functional flow equations for the gauge coupling and the background gauge-field potential. There exists a nontrivial fixed point for both couplings at finite compactification radii. At the fixed point, gauge coupling and vacuum energy are both relevant. The renormalization group flow of the gauge coupling describes the smooth transition between the ultraviolet asymptotically safe regime and the strong interacting infrared limit.

    ↳ hep-thhep-phSciPost Phys.(2023)·7 citations
18. 18*

    Stringy signals from large-angle correlations in the cosmic microwave background?

    Miguel-Angel Sanchis-Lozano🇪🇸

    We interpret the lack of large-angle temperature correlations and the apparent even-odd parity imbalance, observed in the cosmic microwave background by COBE, WMAP and Planck satellite missions, as a possible stringy signal ultimately stemming from a composite inflaton field (e.g. a fermionic condensate). Based on causality arguments and a Fourier analysis of the angular two-point correlation function, two infrared cutoffs $k_{\min }^{\mathrm{even},\mathrm{odd}}$ are introduced in the CMB power spectrum associated, respectively, with periodic and antiperiodic boundary conditions of the fermionic constituents (echoing the Neveu-Schwarz-Ramond model in superstring theory), without resorting to any particular model.

    ↳ astro-ph.COgr-qchep-phhep-thUniverse(2022)·3 citations
19. 19*

    Open quantum system approach for heavy quark thermalization

    Zhuoxuan Xie🇨🇳 · Baoyi Chen🇨🇳

    We treat heavy quark as an open quantum system in the hot medium and rederive the Stochastic Schrödinger Equation (SSE) from the full Schrödinger equation for both heavy quarks and the medium. We apply the SSE to the dynamical evolutions of heavy quarks (as a system) in the static hot medium (as an environment). Heavy quarks interact with the medium via random scatterings, which exchange the momentum and phase factor randomly between two wave functions of the system and the environment. The exchange of momentum and phase factor results in the transition between different eigenstates of the system. These are included via an external stochastic potential in the Hamiltonian of SSE. Stochastic wave functions of heavy quarks are evolved with the stochastic external potential. The mean wave functions and the corresponding momentum distributions of heavy quarks are obtained after the ensemble average over a large set of stochastic wave functions. We present the thermalization of heavy quarks in the static medium with different coupling strength.

    ↳ nucl-thhep-phCPC(2023)·6 citations
20. 20*

    Renormalization of transverse-momentum-dependent parton distribution on the lattice

    Kuan Zhang🇨🇳 · Xiangdong Ji🇺🇸 · Yi-Bo Yang🇨🇳 · Fei Yao🇨🇳 · Jian-Hui Zhang🇨🇳

    To calculate the transverse-momentum-dependent parton distribution functions (TMDPDFs) from lattice QCD, an important goal yet to be realized, it is crucial to establish a viable non-perturbative renormalization approach for linear divergences in the corresponding Euclidean quasi-TMDPDF correlators in large-momentum effective theory. We perform a first systematic study of the renormalization property of the quasi-TMDPDFs by calculating the relevant matrix elements in a pion state at 5 lattice spacings ranging from 0.03 fm to 0.12 fm. We demonstrate that the square root of the Wilson loop combined with the short distance hadron matrix element provides a successful method to remove all ultraviolet divergences of the quasi-TMD operator, and thus provide the necessary justification to perform a continuum limit calculation of TMDPDFs. In contrast, the popular RI/MOM renormalization scheme fails to eliminate all linear divergences.

    ↳ hep-lathep-phPRL(2022)·44 citations
21. 21*

    Anatomy of geometrical destabilization of inflation

    Tomasz Krajewski🇵🇱 · Krzysztof Turzyński🇵🇱

    We study geometrical destabilization of inflation with the aim of determining the fate of excited unstable modes. We use numerical lattice simulations to track the dynamics of both the inflaton and the spectator field. We find that geometrical destabilization is a short-lived phenomenon and that a negative feedback loop prevents field fluctuations from growing indefinitely. As a result, fields undergoing geometrical destabilization are merely shifted to a new classical configuration corresponding to a uniform value of the spectator field within a Hubble patch.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2022)·3 citations
22. 22*

    Anatomy of single-field inflationary models for primordial black holes

    Alexandros Karam🇪🇪 · Niko Koivunen🇪🇪 · Eemeli Tomberg🇪🇪 · Ville Vaskonen🇪🇸 · Hardi Veermäe🇪🇪

    We construct an analytically solvable simplified model that captures the essential features for primordial black hole (PBH) production in most models of single-field inflation. The construction makes use of the Wands duality between the constant-roll (or slow-roll) and the preceding ultra-slow-roll phases and can be realized by a simple inflaton potential of two joined parabolas. Within this framework, it is possible to formulate explicit inflationary scenarios consistent with the CMB observations and copious production of PBHs of arbitrary mass. We quantify the variability of the shape of the peak in the curvature power spectrum in different inflationary scenarios and discuss its implications for probing PBHs with scalar-induced gravitational wave backgrounds. We find that the COBE/Firas $\mu$-distortion constraints exclude the production of PBHs heavier than $10^4{M}_{\odot }$ in single-field inflation.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2023)·152 citations
23. 23*

    Cosmological constraints on decaying axion-like particles: a global analysis

    Csaba Balázs🇦🇺 · Sanjay Bloor🇬🇧 · Tomás E. Gonzalo🇩🇪 · Will Handley🇬🇧 · Sebastian Hoof🇩🇪 · Felix Kahlhoefer🇩🇪 · Marie Lecroq🇦🇺 · David J. E. Marsh🇬🇧 · Janina J. Renk🇬🇧 · Pat Scott🇬🇧 · Patrick Stöcker🇩🇪

    Axion-like particles (ALPs) decaying into photons are known to affect a wide range of astrophysical and cosmological observables. In this study we focus on ALPs with masses in the keV-MeV range and lifetimes between $10^4$ and $10^{13}$ seconds, corresponding to decays between the end of Big Bang Nucleosynthesis and the formation of the Cosmic Microwave Background (CMB). Using the CosmoBit module of the global fitting framework GAMBIT, we combine state-of-the-art calculations of the irreducible ALP freeze-in abundance, primordial element abundances (including photodisintegration through ALP decays), CMB spectral distortions and anisotropies, and constraints from supernovae and stellar cooling. This approach makes it possible for the first time to perform a global analysis of the ALP parameter space while varying the parameters of $\Lambda$CDM as well as several nuisance parameters. We find a lower bound on the ALP mass of around $m_a>300\text{keV}$, which can only be evaded if ALPs are stable on cosmological timescales. Future observations of CMB spectral distortions with a PIXIE-like mission are expected to improve this bound by two orders of magnitude.

    ↳ astro-ph.COhep-phJCAP(2022)·74 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.