Wed·Sep 20, 2023Wednesday·September 20, 2023

1. 01*

   Consequences of a Stabilizing Field's Self-Interactions for RS Cosmology

   Rashmish K. Mishra🇺🇸 · Lisa Randall🇺🇸

   It has been argued that the Randall-Sundrum (RS) phase transition rate is suppressed when the holographic theory corresponds to a large $N$ Yang-Mills and when the stabilizing field has a small mass. Here we argue that self-interactions can alleviate the latter suppression. We consider a cubic term in the bulk potential for the Goldberger-Wise (GW) scalar that is responsible for stabilizing the RS geometry. Adding a cubic term suffices to separate the two roles of the GW stabilization: generating a large hierarchy and triggering confinement. We study the resulting radion potential and the dynamics of the early universe phase transition. For a negative coefficient of the cubic term, the effect of the cubic becomes important in the infra-red, and the resulting radion potential is deeper, thereby increasing the radion mass while maintaining a large hierarchy. Staying within the radion effective field theory, we calculate the rate of bubble nucleation from the hot phase to the confined RS phase, both in thin and thick wall limits. The cubic term enhances the rate and allows relaxing the condition on the maximum number of colors $N_{\text{max}}$ of the dual theory for which the phase transition can be completed. Importantly, this reduces the amount of supercooling that the false vacuum undergoes, increases the peak frequency of the gravitational waves (GW) produced from bubble collisions, and reduces the strength of the GW signal. The reduced GW signal is however still within the reach of proposed space-based GW detectors.

   hep-phhep-thJHEP(2023)·22 citations
2. 02*

   Systematic classification of aGUT models in five dimensions: The SU(N) kinship

   Giacomo Cacciapaglia🇫🇷

   Asymptotic Grand Unification theories (aGUTs) in five dimensions provide a valid alternative to standard quantitative unification. We define the pathway towards viable models starting from a general unified bulk gauge symmetry. Imposing the presence of ultra-violet fixed points for both gauge and Yukawa couplings strongly limits the possibilities. Within the SU(N) kinship, we identify and characterise only two realistic minimal models, both based on a bulk SU(6) symmetry. Both models feature the generation of either up or down-type Yukawas via gauge scalars, two Higgs doublets with build-in minimal flavour violation at low energies, and conservation of baryon number. We also propose interesting avenues beyond the minimality criterion.

   hep-phhep-thJHEP(2023)·7 citations
3. 03*

   $B\to D_0^{\ast }$ and $B_s\to D_{s0}^{\ast }$ form factors from QCD light-cone sum rules

   Nico Gubernari🇩🇪 · Alexander Khodjamirian🇩🇪 · Rusa Mandal🇮🇳 · Thomas Mannel🇩🇪

   We present the first application of QCD light-cone sum rules (LCSRs) with $B_{(s)}$-meson distribution amplitudes to the $B_{(s)}\to D_{(s)0}^{\ast }$ form factors, where $D_{(s)0}^{\ast }$ is a charmed scalar meson. We consider two scenarios for the $D_0^{\ast }$ spectrum. In the first one, we follow the Particle Data Group and consider a single broad resonance $D_0^{\ast }(2300)$. In the second one, we assume the existence of two scalar resonances, $D_0^{\ast }(2105)$ and $D_0^{\ast }(2451)$, as follows from a recent theoretically motivated analysis of $B\to D\pi \pi$ decays. The $B\to D_0^{\ast }$ form factors are calculated in both scenarios, also taking into account the large total width of $D_0^{\ast }(2300)$. Furthermore, we calculate the $B_s\to D_{s0}^{\ast }$ form factors, considering in this case only the one-resonance scenario with $D_{s0}(2317)$. In this LCSRs calculation, the $c$-quark mass is kept finite and the $s$-quark mass is taken into account. We also include contributions of the two- and three-particle distribution amplitudes up to twist-four. Our predictions for semileptonic $B\to D_0^{\ast }\ell {\nu }_{\ell }$ and $B_s\to D_{s0}^{\ast }\ell {\nu }_{\ell }$ branching ratios are compared with the available data and HQET-based predictions. As a byproduct, we also obtain the $D_0^{\ast }$- and $D_{s0}^{\ast }$-meson decay constants and predict the lepton flavour universality ratios $R(D_0^{\ast })$ and $R(D_{s0}^{\ast })$.

   hep-phhep-exJHEP(2023)·14 citations
4. 04*

   Machine Learning Techniques for Intermediate Mass Gap Lepton Partner Searches at the Large Hadron Collider

   Bhaskar Dutta🇺🇸 · Tathagata Ghosh🇮🇳 · Alyssa Horne🇺🇸 · Jason Kumar🇺🇸 · Sean Palmer🇺🇸 · Pearl Sandick🇺🇸 · Marcus Snedeker🇺🇸 · Patrick Stengel🇮🇹 · Joel W. Walker🇺🇸

   We consider machine learning techniques associated with the application of a Boosted Decision Tree (BDT) to searches at the Large Hadron Collider (LHC) for pair-produced lepton partners which decay to leptons and invisible particles. This scenario can arise in the Minimal Supersymmetric Standard Model (MSSM), but can be realized in many other extensions of the Standard Model (SM). We focus on the case of intermediate mass splitting ($\sim 30\mathrm{GeV}$) between the dark matter (DM) and the scalar. For these mass splittings, the LHC has made little improvement over LEP due to large electroweak backgrounds. We find that the use of machine learning techniques can push the LHC well past discovery sensitivity for a benchmark model with a lepton partner mass of $\sim 110\mathrm{GeV}$, for an integrated luminosity of $300{\mathrm{fb}}^{-1}$, with a signal-to-background ratio of $\sim 0.3$. The LHC could exclude models with a lepton partner mass as large as $\sim 160\mathrm{GeV}$ with the same luminosity. The use of machine learning techniques in searches for scalar lepton partners at the LHC could thus definitively probe the parameter space of the MSSM in which scalar muon mediated interactions between SM muons and Majorana singlet DM can both deplete the relic density through dark matter annihilation and satisfy the recently measured anomalous magnetic moment of the muon. We identify several machine learning techniques which can be useful in other LHC searches involving large and complex backgrounds.

   hep-phPRD(2024)·4 citations
5. 05*

   Testable Likelihoods for Beyond-the-Standard Model Fits

   Anja Beck🇬🇧 · Méril Reboud🇬🇧 · Danny van Dyk🇬🇧

   Studying potential BSM effects at the precision frontier requires accurate transfer of information from low-energy measurements to high-energy BSM models. We propose to use normalising flows to construct likelihood functions that achieve this transfer. Likelihood functions constructed in this way provide the means to generate additional samples and admit a ``trivial'' goodness-of-fit test in form of a ${\chi }^2$ test statistic. Here, we study a particular form of normalising flow, apply it to a multi-modal and non-Gaussian example, and quantify the accuracy of the likelihood function and its test statistic.

   hep-phcs.LGEPJC(2023)·3 citations
6. 06*

   Investigating the fluxes and physics potential of LHC neutrino experiments

   Felix Kling🇩🇪 · Toni Mäkelä🇵🇱 · Sebastian Trojanowski🇵🇱

   The initiation of a novel neutrino physics program at the Large Hadron Collider (LHC) and the purpose-built Forward Physics Facility (FPF) proposal have motivated studies exploring the discovery potential of these searches. This requires resolving degeneracies between new predictions and uncertainties in modeling neutrino production in the forward kinematic region. The present work investigates a broad selection of existing predictions for the parent hadron spectra at FASER$\nu$ and the FPF to parameterize expected correlations in the neutrino spectra produced in their decays and to determine the highest achievable precision for their observation based on Fisher information. This allows for setting constraints on various physics processes within and beyond the Standard Model, including neutrino non-standard interactions. We also illustrate how combining multiple neutrino observables could lead to experimental confirmation of the enhanced-strangeness scenario proposed to resolve the cosmic-ray muon puzzle already during the ongoing LHC Run 3.

   hep-phPRD(2023)·35 citations
7. 07*

   Impact of CPV phases on flavour violating $H$ and $Z$ decays

   E. Pinsard🇫🇷 · A. Abada🇫🇷 · J. Kriewald🇸🇮 · S. Rosauro-Alcaraz🇫🇷 · A. M. Teixeira🇫🇷

   Standard Model extensions via heavy neutral leptons lead to modifications in the lepton mixing matrix, including new Dirac and Majorana CP violating phases. Here we consider the role of the Majorana fermions and of new CP violating phases in Higgs and $Z$-boson lepton flavour violating decays, as well as in the corresponding CP-asymmetries. We confirm that these decays are sensitive to the presence of additional sterile states and show that the new CP violating phases may lead to both destructive and constructive interferences in the decay rates. Interestingly the $Z\to {\mu }^{\pm }{\tau }^{\mp }$ rates are within FCC-ee reach, with associated CP-asymmetries that can potentially reach up to 30%.

   hep-phPoS(2024)·0 citations
8. 08*

   Higgs boson pair production at NLO in the POWHEG approach and the top quark mass uncertainties

   Emanuele Bagnaschi🇨🇭 · Giuseppe Degrassi🇮🇹 · Ramona Gröber🇮🇹

   We present a new Monte Carlo code for Higgs boson pair production at next-to-leading order in the POWHEG-BOX Monte Carlo approach. The code is based on analytic results for the two loop virtual corrections which include the full top quark mass dependence. This feature allows to freely assign the value of all input parameters, including the trilinear Higgs boson self coupling, as well as to vary the renormalization scheme employed for the top quark mass. We study the uncertainties due to the top-mass renormalization scheme allowing the trilinear Higgs boson self coupling to vary around its Standard Model value including parton shower effects. Results are presented for both inclusive and differential observables.

   hep-phEPJC(2023)·78 citations
9. 09*

   Signature of Non-Minimal Scalar-Gravity Coupling with an Early Matter Domination on the Power Spectrum of Gravitational Waves

   Amirsalar Nikandish🇮🇷 · Shiva Rostam Zadeh🇮🇷 · Reza Naderi🇮🇷 · Fatemeh Elahi🇩🇪 · Hadi Mehrabpour🇩🇪

   The signal strength of primordial gravitational waves experiencing an epoch of early scalar domination is reduced with respect to radiation domination. In this paper, we demonstrate that the specific pattern of this reduction is sensitive to the coupling between the dominant field and gravity. When this coupling is zero, the impact of early matter domination on gravitational waves is solely attributed to the alteration of the Hubble parameter and the scale factor. In the presence of non-zero couplings, on the other hand, the evolution of primordial gravitational waves is directly affected as well, resulting in a distinct step-like feature in the power spectrum of the gravitational wave as a function of frequency. This feature serves as a smoking gun signature of this model. In this paper, we provide an analytical expression of the power spectrum that illustrates the dependence of power spectrum on model parameters and initial conditions. Furthermore, we provide analytical relations that specify the frequency interval in which the step occurs. We compare the analytical estimates with numerical analysis and show they match well.

   hep-phgr-qcPRD(2024)·2 citations
10. 10*

    The Landscape of Composite Higgs Models

    Mikael Chala🇪🇸 · Renato Fonseca🇪🇸

    We classify all different composite Higgs models (CHMs) characterised by the coset space $\mathcal{G}/\mathcal{H}$ of compact semi-simple Lie groups $\mathcal{G}$ and $\mathcal{H}$ involving up to 13 Nambu-Goldstone bosons (NGBs), together with mild phenomenological constraints. As a byproduct of this work, we prove several simple yet, to the best of our knowledge, mostly unknown results: (1) Under certain conditions, a given set of massless scalars can be UV completed into a CHM in which they arise as NGBs; (2) The set of all CHMs with a fixed number of NGBs is finite, and in particular there are 642 of them with up to 13 massless scalars (factoring out models that differ by extra $U(1)$'s); (3) Any scalar representation of the Standard Model group can be realised within a CHM; (4) Certain symmetries of the scalar sector allowed from the IR perspective are never realised within CHMs. On top of this, we make a simple statistical analysis of the landscape of CHMs, determining the frequency of models with scalar singlets, doublets, triplets and other multiplets of the custodial group as well as their multiplicity. We also count the number of models with a symmetric coset.

    hep-phhep-thJHEP(2024)·1 citation
11. 11*

    Opening the Higgs Portal to Lepton-Flavoured Dark Matter

    Harun Acaroğlu🇩🇪 · Monika Blanke🇩🇪 · Mustafa Tabet🇩🇪

    We study a simplified model of lepton-flavoured complex scalar dark matter coupling to right-handed leptons and the Higgs boson. The model is set up in the Dark Minimal Flavour Violation framework. In contrast to previous studies of similar models we consider the most general case and do not a priori constrain the hierarchy of dark matter masses and couplings in any way. In the first part of the analysis we discuss the impact of Higgs portal interactions and the generalised mass hierarchy on the model's phenomenology. We find that they render new physics masses around the electroweak scale viable, thus qualifying this model to address the $(g-2{)}_{\mu }$ puzzle. After reviewing the current situation of the latter, we perform two combined analyses -- one in which $(g-2{)}_{\mu }$ allows for significant new physics effects and one in which it does not. We find that while the latter scenario allows for a larger range of new physics scales, both scenarios are equally viable.

    hep-phJHEP(2023)·14 citations
12. 12*

    3D Imaging via Polarized Jet Fragmentation Functions and Quantum Simulation of the QCD Phase Diagram

    Fanyi Zhao🇺🇸

    Understanding the interactions between elementary particles and mapping out the internal structure of the hadrons are of fundamental importance in high energy nuclear and particle physics. This thesis concentrates on the strong interaction, described by Quantum Chromodynamics (QCD). We introduce a novel concept called "polarized jet fragmentation functions" and develop the associated theory framework known as QCD factorization which allows us to utilize jet substructure to probe spin dynamics of hadrons, especially nucleon's three-dimensional imaging. Furthermore, non-perturbative QCD studies, particularly of the QCD phase diagram, are important for understanding the properties of hadrons. The development of quantum computing and simulators can potentially improve the accuracy of finite-temperature simulations and allow researchers to explore extreme temperatures and densities in more detail. In this thesis, I present my work in two aspects of QCD studies: (1) investigating the nucleon structure using polarized jet fragmentation functions and (2) illustrating how to apply quantum computing techniques for studying phase diagram of a low energy QCD model. The first category investigates phenomena such as hadron production inside jets, spin asymmetries, etc., providing valuable insight into the behavior of quarks and gluons in hadrons. The second category provides potential applications of quantum computing in QCD and explores the non-perturbative nature of QCD.

    hep-phhep-exhep-latnucl-th+11 citation
13. 13*

    Anharmonic effects in nuclear recoils from sub-GeV dark matter

    Tongyan Lin🇺🇸 · Chia-Hsien Shen🇺🇸 · Mukul Sholapurkar🇺🇸 · Ethan Villarama🇺🇸

    Direct detection experiments are looking for nuclear recoils from scattering of sub-GeV dark matter (DM) in crystals, and have thresholds as low as ~ 10 eV or DM masses of ~ 100 MeV. Future experiments are aiming for even lower thresholds. At such low energies, the free nuclear recoil prescription breaks down, and the relevant final states are phonons in the crystal. Scattering rates into single as well as multiple phonons have already been computed for a harmonic crystal. However, crystals typically exhibit some anharmonicity, which can significantly impact scattering rates in certain kinematic regimes. In this work, we estimate the impact of anharmonic effects on scattering rates for DM in the mass range ~ 1-10 MeV, where the details of multiphonon production are most important. Using a simple model of a nucleus in a bound potential, we find that anharmonicity can modify the scattering rates by up to two orders of magnitude for DM masses of O(MeV). However, such effects are primarily present at high energies where the rates are suppressed, and thus only relevant for very large DM cross sections. We show that anharmonic effects are negligible for masses larger than ~ 10 MeV.

    hep-phhep-exPRD(2024)·6 citations
14. 14*

    Cosmological Collider Signatures of Higgs-$R^2$ Inflation

    Yohei Ema🇺🇸 · Sarunas Verner🇺🇸

    We study the cosmological collider signatures in the Higgs-$R^2$ inflation model. We consider two distinct types of signals: one originating from the inflaton coupling to Standard Model fermions and gauge bosons, and another arising from the isocurvature mode interaction with the inflaton. In the former case, we determine that the signal magnitude is likely too small for detection by upcoming probes, primarily due to suppression by both the Planck scale and slow-roll parameters. However, we provide a detailed computation of the signal which could be potentially applicable to various Higgs inflation variants. For the isocurvature mode signals, we observe that the associated couplings remain unsuppressed when the isocurvature mode is relatively light or comparable to the inflationary scale. In this case, we study the Higgs-$R^2$ inflation parameter space that corresponds to the quasi-single-field inflation regime and find that the signal strength could be as large as $|f_{\mathrm{NL}}|>1$, making Higgs-$R^2$ inflation a viable candidate for observation by future 21-cm surveys.

    hep-phastro-ph.COJCAP(2024)·12 citations
15. 15*

    Milky Way White Dwarfs as Sub-GeV to Multi-TeV Dark Matter Detectors

    Javier F. Acevedo🇺🇸 · Rebecca K. Leane🇺🇸 · Lillian Santos-Olmsted🇺🇸

    We show that Milky Way white dwarfs are excellent targets for dark matter (DM) detection. Using Fermi and H.E.S.S. Galactic center gamma-ray data, we investigate sensitivity to DM annihilating within white dwarfs into long-lived or boosted mediators and producing detectable gamma rays. Depending on the Galactic DM distribution, we set new constraints on the spin-independent scattering cross section down to $10^{-45}-10^{-41}$ cm${}^2$ in the sub-GeV DM mass range, which is multiple orders of magnitude stronger than existing limits. For a generalized NFW DM profile, we find that our white dwarf constraints exceed spin-independent direct detection limits across most of the sub-GeV to multi-TeV DM mass range, achieving sensitivities as low as about $10^{-46}$ cm${}^2$. In addition, we improve earlier versions of the DM capture calculation in white dwarfs, by including the low-temperature distribution of nuclei when the white dwarf approaches crystallization. This yields smaller capture rates than previously calculated by a factor of a few up to two orders of magnitude, depending on white dwarf size and the astrophysical system.

    hep-phastro-ph.HEJCAP(2024)·33 citations
16. 16*

    Dark Matter searches in Dwarf Galaxies with the Southern Wide-field Gamma-ray Observatory

    Micael Andrade🇧🇷 · Aion Viana (for the SWGO collaboration)🇧🇷

    Dark matter is thought to make up most of the matter density of the Universe, yet its true nature remains uncertain. Among dark matter theories, Weakly Interacting Massive Particles (WIMPs) are a prominent candidate for dark matter because they can reproduce the observed abundance of dark matter in the universe. There are various methods for searching for WIMPs, one of which is indirect detection, which involves looking for the Standard Model particles produced by the decay or self-annihilation of dark matter particles. Within the mass range of GeV to PeV for the dark matter particle, this type of search can be conducted by detecting $\gamma$-rays in astrophysical objects with high concentrations of dark matter. Dwarf galaxies, although not the most dense, are excellent targets for this type of observation since they are dominated by dark matter, are relatively close to Earth, and have a low astrophysical background. In this work, the detectability of dark matter annihilation or decay signals from dwarf galaxies is predicted using the Southern Wide-field Gamma-ray Observatory (SWGO), a future $\gamma$-ray observatory that will be built in South America. This wide field-of-view survey instrument will be able to study many important dark matter targets in the Southern Hemisphere, and the combined observation of all targets will provide competitive, if not the best, limits for dark matter with masses in the range of hundreds of GeV to PeV.

    ↳ astro-ph.HEhep-phPoS(2023)·3 citations
17. 17*

    Don't miss the forest for the trees: the Lyman alpha forest power spectrum in effective field theory

    Mikhail M. Ivanov🇺🇸

    We derive an effective field theory (EFT) for cosmological Lyman alpha forest fluctuations valid for the power spectrum at the one-loop order. The ``bottom-up'' EFT expansion at the level of the transmitted flux is identical to the line-of-sight dependent bias model first derived by Desjacques et al. We confirm this result by a ``top-down'' derivation based on the exponential map of the optical depth field. Specifically, we show that the combination of the exponential map and conditions of renormalizability generates the same EFT expansion as the ``bottom-up'' approach. In passing, we point out inconsistencies of the tree-level perturbative expansion of the exponential map without counterterms. To facilitate practical applications, we generalize the FFTLog method for efficient calculations of one-loop integrals from new line-of-sight dependent operators. Finally, we compare the one-loop EFT model against data from the Sherwood hydrodynamic simulation. The theory fits the data with sub percent accuracy up to $k=$ 3 $h$Mpc${}^{-1}$ at $z=2.8$ for both 3D and 1D correlations. Our model can be readily used for cosmological full-shape analyses of Lyman alpha forest data.

    ↳ astro-ph.COhep-phhep-thPRD(2024)·55 citations
18. 18*

    Quark phases in neutron stars consistent with implications of NICER

    Y. Yamamoto🇯🇵 · N. Yasutake🇯🇵 · Th.A. Rijken🇯🇵

    The analyses for the NICER data imply $R_{2.0M_{\odot }}=12.41_{-1.10}^{+1.00}$ km and $R_{1.4M_{\odot }}=12.56_{-1.07}^{+1.00}$ km, indicating the lack of significant variation of the radii from $1.4M_{\odot }$ to $2.0M_{\odot }$. This feature cannot be reproduced by the hadronic matter due to the softening of equation of state (EoS) by hyperon mixing, indicating the possible existence of quark phases in neutron-star interiors. % Two models are used for quark phases: In the quark-hadron transition (QHT) model, quark deconfinement phase transitions from a hadronic-matter EoS are taken into account so as to give reasonable mass-radius ($MR$) curves by adjusting the quark-quark repulsions and the density dependence of effective quark mass. % In the quarkyonic model, the degrees of freedom inside the Fermi sea are treated as quarks and neutrons exist at the surface of the Fermi sea, where $MR$ curves are controlled mainly by the thickness of neutron Fermi layer. % The QHT and quarkyonic EoSs can be adjusted so as to reproduce radii, tidal deformabilities, pressure and central densities inferred from the NICER analysis better than the nucleonic matter EoS, demonstrating the clear impacts of quark phases. Then, the maximum mass for the quakyonic-matter EoS is considerably larger than that for the QHT-matter EoS.

    ↳ nucl-thastro-ph.HEhep-phPRC(2023)·16 citations
19. 19*

    Visualizing quantum coherence and decoherence in nuclear reactions

    K. Hagino🇯🇵 · T. Yoda

    Differential cross sections of nuclear reactions often exhibit characteristic oscillations in the angular distribution originated from an interference of two indistinguishable processes. Here we propose a novel method to visualize origins of such oscillations. This is achieved by taking Fourier transform of scattering amplitudes, following the idea in wave optics. We apply this method to elastic scattering of ${}^{16}$O+${}^{16}$O and ${}^{18}$O+${}^{18}$O at energies above the Coulomb barrier. The former system shows strong oscillations in the angular distribution due to the nearside-farside interferences, while the oscillations are largely suppressed in the latter system due to a stronger absorption. We show that the image of the former and the latter systems corresponds to a double-slit and a single-slit problems in quantum mechanics, respectively.

    ↳ nucl-thhep-phhep-thnucl-exPLB(2024)·5 citations
20. 20*

    Stasis, Stasis, Triple Stasis

    Keith R. Dienes🇺🇸 · Lucien Heurtier🇬🇧 · Fei Huang🇮🇱 · Tim M.P. Tait🇺🇸 · Brooks Thomas🇺🇸

    Many theories of BSM physics predict the existence of large or infinite towers of decaying states. In a previous paper (arXiv:2111.04753) we pointed out that this can give rise to a surprising cosmological phenomenon that we dubbed "stasis" during which the relative abundances of matter and radiation remain constant across extended cosmological eras even though the universe is expanding. Indeed, such stasis epochs are universal attractors, with the universe necessarily entering (and later exiting) such epochs for a wide variety of initial conditions. Matter/radiation stasis is therefore an important and potentially unavoidable feature of many BSM cosmologies. In this paper we extend our arguments to universes containing significant amounts of vacuum energy, and demonstrate that such universes also give rise to various forms of stasis between vacuum energy and either matter or radiation. We also demonstrate the existence of several forms of "triple stasis" during which the abundances of matter, radiation, and vacuum energy all simultaneously remain fixed despite cosmological expansion. We further describe several close variants of stasis which we call "quasi-stasis" and "oscillatory stasis" and discuss the circumstances under which each of these can arise. Finally, we develop a general formalism for understanding the emergence of stasis within BSM cosmologies irrespective of the number or type of different energy components involved. Taken together, these results greatly expand the range of theoretical and phenomenological possibilities for the physics of the early universe, introducing new types of cosmological eras which may play an intrinsic and potentially inevitable role within numerous BSM cosmologies.

    ↳ astro-ph.COhep-phhep-thPRD(2024)·21 citations
21. 21*

    The perturbative vacua in string geometry theory

    Koichi Nagasaki🇯🇵 · Matsuo Sato🇯🇵 · Gota Tanaka🇯🇵

    String geometry theory is one of the candidates of the non-perturbative formulation of string theory. In this paper, in the bosonic closed sector of string geometry theory, we completely identify the perturbative vacua, which include general string backgrounds in bosonic closed string theory. From fluctuations around these configurations, we derive the path-integrals of perturbative strings on the string backgrounds up to any order.

    ↳ hep-thgr-qchep-phmath.DG+17 citations
22. 22*

    The Sign of non-Gaussianity and the Primordial Black Holes Abundance

    Hassan Firouzjahi🇮🇷 · Antonio Riotto🇨🇭

    The abundance of primordial black holes changes in the presence of local non-Gaussianity. A positive non-linear parameter $f_{NL}$ increases the abundance while a negative one reduces it. We show that in non-attractor single-field models of inflation which enhance the curvature power spectrum and may give rise to primordial black holes, $f_{NL}$ is always positive, when computed in correspondence of the peak of the curvature power spectrum where the primordial black hole abundance has its maximum. This implies that the interpretation of the recent pulsar timing arrays data from scalar-induced gravitational waves generated at primordial black hole formation may not be supported by invoking non-Gaussianity within non-attractor single-field models.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2023)·41 citations
23. 23*

    Influences of tilted thin accretion disks on the observational appearance of hairy black holes in Horndeski gravity

    Shiyang Hu · Dan Li🇨🇳 · Chen Deng🇨🇳 · Xin Wu🇨🇳 · Enwei Liang🇨🇳

    Research on the observational appearance of black holes, both in general relativity and modified gravity, has been in full swing since the Event Horizon Telescope Collaboration announced photos of M87${}^{\ast }$ and Sagittarius A${}^{\ast }$. Nevertheless, limited attention has been given to the impact of tilted accretion disks on black hole images. This paper investigates the $230$ GHz images of non-rotating hairy black holes illuminated by tilted, thin accretion disks in Horndeski gravity with the aid of a ray tracing method. The results indicate that reducing the scalar hair parameter effectively diminishes image luminosity and extends both the critical curve and the inner shadow. This trend facilitates the differentiation between hairy black holes and Schwarzschild black holes, especially in certain parameter spaces where the current Event Horizon Telescope array is capable of capturing such variations. Furthermore, we observe that the inclination of the tilted accretion disk can mimic the observation angle, consequently affecting image brightness and the morphology of the inner shadow. In specific parameter spaces, alterations in the tilt or position of the accretion disk can lead to a drift in the light spot within the images of hairy black holes. This finding may establish a potential correlation between the precession of the tilted accretion disk and image features. Additionally, through an examination of images depicting hairy black holes surrounded by two thin accretion disks, we report the obscuring effect of the accretion environment on the inner shadow of the black hole.

    ↳ gr-qcastro-ph.HEhep-phJCAP(2024)·29 citations
24. 24*

    Impact of a nearby subhalo on the constraint of dark matter annihilation from cosmic ray antiprotons

    Yi Zhao🇨🇳 · Xiao-Jun Bi🇨🇳 · Su-Jie Lin🇨🇳 · Peng-Fei Yin🇨🇳

    Numerous simulations indicate that a large number of subhalos should be hosted by the Milky Way. The potential existence of a nearby subhalo could have important implications for our understanding of dark matter (DM) annihilation. In this study, we investigate the hypothetical presence of a nearby subhalo and set the upper limits on the DM annihilation cross section by analyzing the cosmic-ray antiproton spectrum. By presenting the ratios of annihilation cross section limits for scenarios with and without a nearby subhalo, we can quantitatively evaluate the potential impact of the nearby subhalo on the limits of the DM annihilation cross section. The impacts of the concentration model and the subhalo probability distribution have been considered. We explore the antiproton contribution of the potential nearby DM subhalo accounting for the DAMPE $e^{\pm }$ spectrum at $\sim 1.4$ TeV and find that the current AMS-02 antiproton results do not place the constraint on this contribution.

    ↳ astro-ph.HEhep-phCPC(2024)·1 citation
25. 25*

    Atmospheric Temperature anomalies as manifestation of the dark Universe

    K. Zioutas🇬🇷 · V. Anastassopoulos🇬🇷 · A. Argiriou🇬🇷 · G. Cantatore🇮🇹 · S. Cetin🇹🇷 · H. Fischer🇩🇪 · A. Gardikiotis🇬🇷 · H. Haralambous🇨🇾 · D. H. H. Hoffmann🇨🇳 · S. Hofmann🇩🇪 · M. Karuza🇭🇷 · A. Kryemadhi🇺🇸 and 5 other authors

    We are investigating the possible origin of small-scale anomalies, like the annual stratospheric temperature anomalies. Unexpectedly within known physics, their observed planetary "dependency", does not match concurrent solar activity, whose impact on the atmosphere is unequivocal; this points at an additional energy source of exo-solar origin. A viable concept behind such observations is based on possible gravitational focusing by the Sun and its planets towards the Earth of low-speed invisible streaming matter; its influx towards the Earth gets temporally enhanced. Only a somehow "strongly" interacting invisible streaming matter with the small upper atmospheric screening can be behind the observed temperature excursions. Ordinary dark matter (DM) candidates like axions or WIMPs, cannot have any noticeable impact. The associated energy deposition is $\mathcal{O}(\sim 1000\mathrm{GeV}/{\mathrm{cm}}^2/\sec )$. The atmosphere has been uninterruptedly monitored for decades. Therefore, the upper atmosphere can serve as a novel (low-threshold) detector for the dark Universe, with built-in spatiotemporal resolution while the solar system gravity acts temporally as a signal amplifier. Interestingly, the anomalous ionosphere shows a relationship with the inner earth activity like earthquakes. Similarly investigating the transient sudden stratospheric warmings within the same reasoning, the nature of the assumed "invisible streams" could be deciphered.

    ↳ astro-ph.EPastro-ph.IMhep-phphysics.ao-ph2 citations
26. 26*

    Inflation Correlators with Multiple Massive Exchanges

    Zhong-Zhi Xianyu🇨🇳 · Jiaju Zang🇨🇳

    The most general tree-level boundary correlation functions of quantum fields in inflationary spacetime involve multiple exchanges of massive states in the bulk, which are technically difficult to compute due to the multi-layer nested time integrals in the Schwinger-Keldysh formalism. On the other hand, correlators with multiple massive exchanges are well motivated in cosmological collider physics, with the original quasi-single-field inflation model as a notable example. In this work, with the partial Mellin-Barnes representation, we derive a simple rule, called family-tree decomposition, for directly writing down analytical answers for arbitrary nested time integrals in terms of multi-variable hypergeometric series. We present the derivation of this rule together with many explicit examples. This result allows us to obtain analytical expressions for general tree-level inflation correlators with multiple massive exchanges. As an example, we present the full analytical results for a range of tree correlators with two massive exchanges.

    ↳ hep-thastro-ph.COhep-phJHEP(2024)·54 citations

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