Mon·Oct 25, 2021Monday·October 25, 2021

1. 01*

   Two-loop amplitudes for di-Higgs and di-pseudo-Higgs productions through quark annihilation in QCD

   Taushif Ahmed🇮🇹 · V. Ravindran🇮🇳 · Aparna Sankar🇮🇳 · Surabhi Tiwari🇮🇳

   Through this article, we present the two-loop massless QCD corrections to the production of di-Higgs and di-pseudo-Higgs boson through quark annihilation in the large top quark mass limit. Within dimensional regularisation, we employ the non-anticommuting ${\gamma }_5$ and treat it under the Larin prescription. We discover the absence of any additional renormalisation, so-called contact renormalisation, that could arise from the short distance behaviour of two local operators. This finding is in corroboration with the operator product expansion. By examining the results, we discover the lack of similarity in the highest transcendentality weight terms between these finite remainders and that of a pair of half-BPS primary operators in maximally supersymmetric Yang-Mills theory. We need these newly computed finite remainders to calculate observables involving di-Higgs or di-pseudo-Higgs at the next-to-next-to-leading order. We implement the results to a numerical code for further phenomenological studies.

   hep-phhep-exJHEP(2022)·7 citations
2. 02*

   CTEQ-TEA group updates: Photon PDF and Impact from heavy flavors in the CT18 global analysis

   Marco Guzzi🇺🇸 · Keping Xie🇺🇸 · Tie-Jiun Hou🇨🇳 · Pavel Nadolsky🇺🇸 · Carl Schmidt🇺🇸 · Mengshi Yan🇨🇳 · C.-P. Yuan🇺🇸

   We discuss recent CTEQ-TEA group activities after the publication of the CT18 global analysis of parton distribution functions (PDFs) in the proton. In particular, we discuss a new calculation for the photon content in the proton, termed as CT18lux and CT18qed PDFs, and the impact of novel charm- and bottom-quark production cross section measurements at HERA on the CT18 global analysis.

   hep-phPoS(2022)·2 citations
3. 03*

   Azimuthal Angular Correlation as a Boosted Top Jet Substructure

   Zhite Yu🇺🇸 · C.-P. Yuan🇺🇸

   We propose a novel jet substructure observable of boosted tops that is related to the linear polarization of the $W$ boson in boosted top quark decay, which results in a $\cos 2\varphi$ angular correlation between the $t\to bW$ and $W\to f\overline{f^{\prime }}$ decay planes. We discuss in detail the origin of such linear polarization by applying Wigner's little group transformation. We show that the unique $\cos 2\varphi$ angular correlation only exists in the boosted regime but not in the top quark rest frame. We construct an experimental observable for such correlation based on the transverse energy deposition asymmetry in the top jet that does not require the reconstruction of $W$ decay products. The degree of this asymmetry can be used to measure the longitudinal polarization of the top quark, which is an important probe of new physics that couples to the top sector, and can discriminate a boosted top quark jet from its background events, such as QCD jets. A numerical simulation is also performed and found to agree well with the analytic prediction of the Standard Model.

   hep-phPRL(2022)·14 citations
4. 04*

   Comment on "New physics constraints from atomic parity violation in 133-Cs"

   B. M. Roberts🇦🇺 · J. S. M. Ginges🇦🇺

   In a recent Letter [B. K. Sahoo, B. P. Das, and H. Spiesberger, Phys. Rev. D 103, L111303 (2021)], a calculation of the parity violating 6S-7S E1 amplitude in Cs is reported, claiming an uncertainty of just 0.3%. In this Comment, we point out that key contributions have been omitted, and the theoretical uncertainty has been significantly underestimated. In particular, the contribution of missed QED radiative corrections amounts to several times the claimed uncertainty.

   hep-phphysics.atom-phPRD(2022)·14 citations
5. 05*

   Self-interacting dark matter from late decays and the $H_0$ tension

   Krzysztof Jodłowski🇵🇱

   We investigate a mechanism for the production of self-interacting dark matter based on WIMP-like messenger state decays into dark matter and dark radiation occurring after recombination. Such a transition leads to a mild relaxation of the Hubble tension, and at the same time may resolve the small-scale structure problems of the $\Lambda$CDM. We illustrate this mechanism in the Higgs portal dark matter model, which we find to be a promising route.

   hep-phastro-ph.COPoS·0 citations
6. 06*

   Probing an intrinsically flavorful ALP via tau-lepton flavor physics

   Chuan-Xin Cui🇨🇳 · Hiroyuki Ishida🇯🇵 · Shinya Matsuzaki🇨🇳 · Yoshihiro Shigekami🇨🇳

   Any axionlike particle (ALP) intrinsically possesses flavorful couplings to the standard model (SM) fermions arising as a consequence of the right-handed flavor rotation within the SM. In this paper we discuss this intrinsically flavored ALP, and explore the correlation of a minimal set of the couplings in a view of coherence in flavor physics observables. We focus particularly on the tau-lepton flavor violation (LFV). The ALP is assumed to be tau-philic on a current-eigenstate basis, a la Pecci-Quinn. The ALP has the intrinsic flavorful coupling structure for fermions, which allows coupling also to muon and electron only in a right-handed specific manner. Several LFV processes are generated including radiative tau decays and also anomalous magnetic moments of electron and muon. We first pay attention to two separated limits: electron scenario with the ALP coupled to tau which mixes only with right-handed electron, and muon scenario as the muonic counterpart of the electron scenario. It turns out that those scenarios are highly constrained by experimental limits, to require a mu or electron - tau flipped feature in the mass eigenbasis when coupled to the ALP. We then examine a hybrid scenario, and find a fully viable parameter space on the ALP mass-photon coupling plane, which limits the ALP mass to be (1.7 - 10) GeV and the ALP decay constant $f_a$ to be (12.8 - 67.9) GeV. We find that the same-sign multilepton signal at Belle II is a smoking-gun to probe the present ALP signal, and the polarization asymmetry in LFV radiative $\tau$ decay is a punchline, which definitely predicts preference of the right-handed polarization, in sharp contrast to the SM plus massive Dirac neutrinos having the highly left-handed preference, and also other light-new physics candidates. Possible model-building to underlie the present third-generation specific ALP is also briefly addressed.

   hep-phPRD(2022)·7 citations
7. 07*

   FIESTA5: numerical high-performance Feynman integral evaluation

   A. V. Smirnov🇷🇺 · N. D. Shapurov🇷🇺 · L. I. Vysotsky🇷🇺

   In this paper we present a new release of the FIESTA program (Feynman Integral Evaluation by a Sector decomposiTion Approach). FIESTA5 is performance-oriented - we implemented improvements of various kinds in order to make Feynman integral evaluation faster. We plugged in two new integrators, the Quasi Monte Carlo and Tensor Train. At the same time the old code of FIESTA4 was upgraded to the C++17 standard and mostly rewritten without self-made structures such as hash tables. There are also several essential improvements which are most relevant for complex integrations - the new release is capable of producing results where previously impossible.

   hep-phComput.Phys.Commun.(2022)·135 citations
8. 08*

   Analytic derivation of the non-linear gluon distribution function

   G.R.Boroun🇮🇷

   In the present article, two analytical solutions based on the Laplace transforms method for the linear and non-linear gluon distribution functions have been presented at low values of $x$. These linear and non-linear methods are presented based on the solutions of the Dokshitzer-Gribov- Lipatov-Altarelli-Parisi (DGLAP) evolution equation and the Gribov-Levin-Ryskin Mueller-Qiu (GLR-MQ) equation at the leading-order accuracy in perturbative QCD respectively. The gluon distributions are obtained directly in terms of the parametrization of structure function $F_2(x,Q^2)$ and its derivative and compared with the results from the parametrization models. The $n_f$ changes at the threshold are considered in the numerical results. The effects of the non-linear corrections are visible as $Q^2$ decreases and vanish as $Q^2$ increases. The nonlinear corrections tame the behavior of the gluon distribution function at low $x$ and $Q^2$ in comparison with the parametrization models.

   hep-phEur.Phys.J.Plus(2022)·4 citations
9. 09*

   QCD-based estimate of direct $CP$ asymmetry in charm decays

   Alexander Khodjamirian🇩🇪

   I discuss the calculation of the direct CP-asymmetry in $D\to {\pi }^{+}{\pi }^{-}$ and $D\to K^{+}{K}^{-}$ decays with the method of QCD light-cone sum rules. The main result is the upper limit for the difference of the two asymmetries $\left|\Delta a_{CP}^{dir}\right|<0.020\pm 0.003\%$ which is significantly smaller than the recent measurement of this quantity by the LHCb collaboration

   hep-phPoS(2021)·1 citation
10. 10*

    Matching-invariant running quark masses in Quantum Chromodynamics

    H. M. Chen🇨🇳 · L. M. Liu🇨🇳 · J. T. Wang🇨🇳 · M. Waqas🇨🇳 · G. X. Peng🇨🇳

    The conventional quark mass is not continuous at thresholds. In this paper, we derive matchinginvariant quark masses which are continuous everywhere. They are expanded as an obvious function of the logarithmic Lambda scaled energy. The expansion coefficients are related to the original gamma and beta functions, with concretization to four loop level. The results show that the new expressions for the quark masses converge indeed much faster.

    hep-phIJMPE(2022)·20 citations
11. 11*

    Limiting the Heavy-quark and Gluon-philic Real Dark Matter

    Sukanta Dutta🇮🇳 · Lalit Kumar Saini🇮🇳

    We investigate the phenomenological viability of real spin half, zero and one dark matter candidates, which interact predominantly with third generation heavy quarks and gluons via the twenty-eight gauge invariant higher dimensional effective operators. The corresponding Wilson coefficients are constrained one at a time from the relic density ${\Omega }^{\mathrm{DM}}{h}^2$ $\approx$ 0.1198. Their contributions to the thermal averaged annihilation cross-sections are shown to be consistent with the FermiLAT and H.E.S.S. experiments' projected upper bound on the annihilation cross-section in the $b\bar{b}$ mode. The tree-level gluon-philic and one-loop induced heavy-quark-philic DM-nucleon direct-detection cross-sections are analysed. The non-observation of any excess over expected background in the case of recoiled Xe-nucleus events for spin-independent DM-nucleus scattering in XENON-1T sets the upper limits on the eighteen Wilson coefficients. Our analysis validates the real DM candidates for the large range of accessible mass spectrum below 2 TeV for all but one interaction induced by the said operators.

    hep-phPRD(2022)·1 citation
12. 12*

    Primordial neutrino asymmetry evolution with full mean-field effects and collisions

    Julien Froustey🇫🇷 · Cyril Pitrou🇫🇷

    Neutrino oscillations and mean-field effects considerably enrich the phenomenology of neutrino evolution in the early Universe. Taking into account these effects, most notably the neutrino self-interaction mean-field contribution, we revisit the problem of the evolution of primordial neutrino asymmetries including for the first time the complete expression for collisions, which describe scattering and annihilations with electrons/positrons and reactions among (anti)neutrinos. We show that a generalisation of the adiabatic transfer of averaged oscillations (ATAO) scheme, a numerical method previously developed without neutrino degeneracy and based on the large separation of time scales in this problem, is sufficient to reach the same accuracy as the full quantum kinetic equation integration, but is notably faster. This approximation highlights the physics of synchronous oscillations at play in the evolution of neutrino chemical potentials, especially in the particular case with only two-neutrino mixing. In particular, it allows to understand what controls the beginning and the amplitude of oscillations, but also why there is a subsequent regime of collective oscillations with larger frequencies. We also find that it is very important to use the full collision term instead of relying on damping-like approximations, in order not to overestimate how collisions reduce these synchronous oscillations. Finally we study qualitatively how mixing parameters affect the final neutrino configuration, and in particular we show that the CP-violating Dirac phase cannot substantially affect the final $N_{\mathrm{eff}}$ nor the final electronic (anti)-neutrino spectrum, and thus should not affect cosmological observables.

    hep-phastro-ph.COJCAP(2022)·49 citations
13. 13*

    High-energy elastic diffractive scattering of nucleons in the framework of the two-Reggeon eikonal approximation (from U-70 to LHC)

    A.A. Godizov🇷🇺

    Elastic diffractive scattering of nucleons is described in terms of Regge-eikonal approach. It is demonstrated that, in a wide kinematic region (starting from the U-70 energies), the eikonal of proton-proton scattering can be approximated by the sum of two Reggeon exchange terms (namely, the so-called soft Pomeron and $f$-Reggeon contributions). The range of applicability of the considered approximation is determined. The predictive value of the proposed phenomenological scheme is verified.

    hep-phhep-exEPJC(2022)·6 citations
14. 14*

    Intermittency Analysis of Toy Monte Carlo Events

    Sheetal Sharma🇮🇳 · Ramni Gupta🇮🇳

    Event-by-event intermittency analysis of Toy Monte Carlo events is performed in the scenario of high multiplicity events as is the case at recent colliders RHIC and LHC for AA collisions. A power law behaviour of Normalized Factorial Moments (NFM), $F_q$ as function of number of bins ($M$) known as intermittency, is a signature of self-similar fluctuations. Dependence of NFM on the detector efficiencies and on the presence of fluctuations have been studied. Results presented here provide a baseline to the experimental results and clarity on the application of efficiency corrections to the experimental data.

    hep-phhep-exSciPost Phys.Proc.(2022)·3 citations
15. 15*

    Why interpretation matters for BSM searches: a case study with Heavy Neutral Leptons at ATLAS

    Jean-Loup Tastet🇩🇰 · Oleg Ruchayskiy🇩🇰 · Inar Timiryasov🇨🇭

    Experiments searching for Heavy Neutral Leptons (HNLs) typically interpret their results within simplified models consisting of a single HNL coupled to a single lepton flavor. However, any model which aims to describe neutrino oscillations necessarily features more than one HNL, coupled to several flavors. As we show in this work, the reinterpretation of the results of experimental searches in terms of realistic models is a non-trivial task. We perform a detailed reinterpretation of the latest ATLAS search for prompt HNLs in W decays within a minimal low-scale seesaw with two HNLs. We show that the exclusion limits obtained using the detailed reinterpretation can differ by several orders of magnitude from the limits quoted for the simplified models. Hence naively comparing the mixing angles from a realistic model to the reported limits could lead to wrongly excluding entire regions of parameter space! To overcome this issue without requiring experiments to report constraints on all possible HNL models, we propose a simple framework that allows one to easily and accurately reinterpret exclusion limits within closely-related models. We outline a number of concrete steps that can be taken by experiments to implement this method with minimal effort, and we discuss its applicability to other models of feebly interacting particles.

    hep-phhep-exPoS(2022)·5 citations
16. 16*

    Review of a light NMSSM pseudoscalar Higgs state production at the LHC

    M. M. Almarashi🇸🇦

    In this paper we briefly review the LHC discovery potential of a light pseudoscalar Higgs boson of the NMSSM, $a_1$, produced in the gluon fusion $gg\to a_1$ , bottom-quark fusion $b\bar{b}\to a_1$ and bottom-gluon fusion $bg\to b{a}_1$. We also review the LHC discovery potential of the next-to-lightest CP-even Higgs boson $h_2$ being the non-SM-like Higgs, decaying either into two light CP-odd Higgs bosons $a_1{a}_1$ or into a light $a_1$ and the $Z$ gauge boson through the gluon fusion $gg\to h_2$ in the 4$\tau$ final state. We find that the light $a_1$ can be detected at the LHC in a variety of production processes including the gluon fusion, bottom-quark fusion and bottom-gluon fusion. The latter two processes require high luminosity of the LHC and large values of tan$\beta$. We also find that the LHC has the potential to discover the non-SM-like Higgs state, $h_2$, decaying into a pair of light CP-odd Higgses $a_1$'s, allowing to distinguish the NMSSM Higgs sector from the MSSM one as such a light $a_1$ is impossible in the latter scenario.

    hep-phUniverse(2021)·2 citations
17. 17*

    Solutions to the MiniBooNE Anomaly from New Physics in Charged Meson Decays

    Bhaskar Dutta🇺🇸 · Doojin Kim🇺🇸 · Adrian Thompson🇺🇸 · Remington T. Thornton🇺🇸 · Richard G. Van de Water🇺🇸

    We point out that production of new bosons by charged meson decays can greatly enhance the sensitivity of beam-focused accelerator-based experiments to new physics signals. This enhancement arises since the charged mesons are focused and their three-body decays do not suffer from helicity suppression in the same way as their usual two-body decays. As a realistic application, we attempt to explain the MiniBooNE low energy excess utilizing this overlooked mechanism, uniquely realizing dark-sector interpretations as plausible solutions to the excess. As proof of the principle, we consider two well-motivated classes of dark-sector models, models of vector-portal dark matter and models of long-lived (pseudo)scalar. We argue that the model parameter values to accommodate the excess are consistent with existing limits and that they can be tested at current and future accelerator-based neutrino experiments.

    hep-phhep-exPRL(2022)·58 citations
18. 18*

    $\mathcal{O}({\alpha }_s^3)$ corrections to semileptonic $b\to c$ decays in the heavy daughter approximation

    Kay Schönwald🇩🇪

    We present our recent calculation of the third order corrections to the semileptonic $b\to c$ and the muon decays. The calculation has been performed in an expansion around the limit $m_c\sim m_b$, but shows decent convergence even for $m_c=0$ from which the contribution to the muon decay can be extracted. For the semileptonic $b\to c$ decay we find large perturbative corrections in the on-shell scheme which can be significantly reduced by changing to the kinetic scheme for the bottom quark mass. These results are important input for the inclusive determination of $|V_{cb}|$ and the Fermi coupling constant $G_F$.

    hep-phSciPost Phys.Proc.(2022)·0 citations
19. 19*

    Euclid: Forecast constraints on consistency tests of the $\Lambda$CDM model

    S. Nesseris🇪🇸 · D. Sapone🇨🇱 · M. Martinelli🇪🇸 · D. Camarena🇧🇷 · V. Marra🇧🇷 · Z. Sakr🇱🇧 · J. Garcia-Bellido🇪🇸 · C.J.A.P. Martins🇵🇹 · C. Clarkson🇬🇧 · A. Da Silva🇵🇹 · P. Fleury🇪🇸 · L. Lombriser🇨🇭 and 103 other authors

    The standard cosmological model is based on the fundamental assumptions of a spatially homogeneous and isotropic universe on large scales. An observational detection of a violation of these assumptions at any redshift would immediately indicate the presence of new physics. We quantify the ability of the Euclid mission, together with contemporary surveys, to improve the current sensitivity of null tests of the canonical cosmological constant $\Lambda$ and the cold dark matter (LCDM) model in the redshift range $0<z<1.8$. We considered both currently available data and simulated Euclid and external data products based on a LCDM fiducial model, an evolving dark energy model assuming the Chevallier-Polarski-Linder (CPL) parameterization or an inhomogeneous Lema\^ıtre-Tolman-Bondi model with a cosmological constant $\Lambda$ (LLTB), and carried out two separate but complementary analyses: a machine learning reconstruction of the null tests based on genetic algorithms, and a theory-agnostic parametric approach based on Taylor expansion and binning of the data, in order to avoid assumptions about any particular model. We find that in combination with external probes, Euclid can improve current constraints on null tests of the LCDM by approximately a factor of three when using the machine learning approach and by a further factor of two in the case of the parametric approach. However, we also find that in certain cases, the parametric approach may be biased against or missing some features of models far from LCDM. Our analysis highlights the importance of synergies between Euclid and other surveys. These synergies are crucial for providing tighter constraints over an extended redshift range for a plethora of different consistency tests of some of the main assumptions of the current cosmological paradigm.

    ↳ astro-ph.COgr-qchep-phAstron.Astrophys.(2022)·36 citations
20. 20*

    Dynamical Noncommutative Graphene

    Ilyas Haouam🇩🇿 · S Ali Alavi🇮🇷

    We study graphene in a two-dimensional dynamical noncommutative space in the presence of a constant magnetic field. The model is solved using perturbation theory and to the second order of perturbation. The energy levels of the system are calculated and the corresponding eigenstates are obtained. For all cases, the energy shift depends on the dynamical noncommutative parameter {\tau}. Using the accuracy of energy measurement we put an upper bound on the noncommutativity parameter {\tau}. In addition, we investigate some of the thermodynamic quantities of the system at zero temperature limit and extreme relativistic case, which reveals interesting differences between commutative and dynamical noncommutative spaces.

    ↳ quant-phhep-phhep-thmath-ph+1Int.J.Mod.Phys.A(2022)·15 citations
21. 21*

    State mixing and masses of the ${\pi }^0$, $\eta$ and ${\eta }^{\prime }$ mesons from $n_f=1+1+1$ lattice QCD+QED

    Z. R. Kordov🇦🇺 · R. Horsley🇬🇧 · W. Kamleh🇦🇺 · Z. Koumi🇦🇺 · Y. Nakamura🇯🇵 · H. Perlt🇩🇪 · P. E. L. Rakow🇬🇧 · G. Schierholz🇩🇪 · H. Stüben🇩🇪 · R. D. Young🇦🇺 · J. M. Zanotti🇦🇺

    We present a lattice analysis of the light pseudoscalar mesons with consideration for the mixing between the flavour-neutral states ${\pi }^0$, $\eta$ and ${\eta }^{\prime }$. We extract the masses and flavour compositions of the pseudoscalar meson nonet in $n_f=1+1+1$ lattice QCD+QED around an SU(3)-flavour symmetric point, and observe flavour-symmetry features of the extracted data, along with preliminary extrapolation results for the flavour compositions at the physical point. A key result of this work is the observed mass splitting between the ${\pi }^0$ and $\eta$ on our ensembles, which is found to exhibit behaviour that is simply related to the corresponding flavour compositions.

    ↳ hep-lathep-phnucl-thPRD(2021)·14 citations
22. 22*

    Static quark anti-quark interactions at non-zero temperature from lattice QCD

    Dibyendu Bala🇩🇪 · Olaf Kaczmarek🇩🇪 · Rasmus Larsen🇳🇴 · Swagato Mukherjee🇺🇸 · Gaurang Parkar🇳🇴 · Peter Petreczky🇺🇸 · Alexander Rothkopf🇳🇴 · Johannes Heinrich Weber🇩🇪

    We study the interactions of a static quark antiquark pair at non-zero temperature using realistic 2+1 flavor lattice QCD calculations. The study consists of two parts: the first investigates the properties of Wilson line correlators in Coulomb gauge and compares to predictions of hard-thermal loop perturbation theory. As a second step we extract the spectral functions underlying the correlators using four conceptually different methods: spectral function fits, a HTL inspired fit for the correlation function, Padé rational approximation and the Bayesian BR spectral reconstruction. We find that our high statistics Euclidean lattice data are amenable to different hypotheses for the shapes of the spectral function and we compare the implications of each analysis method for the existence and properties of a well defined ground state spectral peak.

    ↳ hep-lathep-phnucl-thPRD(2022)·80 citations
23. 23*

    Hamiltonian formalism for cosmological perturbations: the separate-universe approach

    Danilo Artigas🇫🇷 · Julien Grain🇫🇷 · Vincent Vennin🇫🇷

    The separate-universe approach provides an effective description of cosmological perturbations at large scales, where the universe can be described by an ensemble of independent, locally homogeneous and isotropic patches. By reducing the phase space to homogeneous and isotropic degrees of freedom, it greatly simplifies the analysis of large-scale fluctuations. It is also a prerequisite for the stochastic-inflation formalism. In this work, we formulate the separate-universe approach in the Hamiltonian formalism, which allows us to analyse the full phase-space structure of the perturbations. Such a phase-space description is indeed required in dynamical regimes which do not benefit from a background attractor, as well as to investigate quantum properties of cosmological perturbations. We find that the separate-universe approach always succeeds in reproducing the same phase-space dynamics for homogeneous and isotropic degrees of freedom as the full cosmological perturbation theory, provided that the wavelength of the modes under consideration are larger than some lower bound that we derive. We also compare the separate-universe approach and cosmological perturbation theory at the level of the gauge-matching procedure, where the agreement is not always guaranteed and requires specific matching prescriptions that we present.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2022)·38 citations
24. 24*

    Background of radio photons from primordial black holes

    Shikhar Mittal (TIFR)🇮🇳 · Girish Kulkarni (TIFR)🇮🇳

    We compute the isotropic radiation background due to Hawking emission from primordial black holes (PBHs), and examine if this background is a viable option in explaining the excess radiowave background observed by the ARCADE2 and LWA1 experiments at $\lesssim 1$GHz. We find that even under the extreme assumption that all of the dark matter is in the form of PBHs, the radio brightness temperature induced by Hawking evaporation of PBHs is $\mathcal{O}(10^{-46})$K, highly subdominant compared to the cosmic microwave background. The main reason for this is that for PBHs in the mass range $\sim 10^{12}$-$10^{14}$kg, which can be constrained by Hawking emission, the spectrum peaks at $10^7$ to $10^5$eV. As the Hawking spectrum is power law suppressed towards lower energies, negligible flux of $\mu$eV photons is obtained. The peak of the Hawking spectrum shifts to lower energies for higher masses, but the number density is low and so is the specific intensity. Because Hawking emission from PBHs is thus unable to explain the observed excess radio background, we also consider the alternative possibility of radio emission from gas accretion onto supermassive PBHs. These PBHs can readily produce strong radio emission that could easily explain the ARCADE2/LWA1 excess.

    ↳ astro-ph.COhep-phhep-thMNRAS(2022)·35 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.