Tue·Mar 14, 2023Tuesday·March 14, 2023

1. 01*

   Pion stars embedded in neutrino clouds

   O. S. Stashko🇺🇸 · O. V. Savchuk🇺🇸 · L. M. Satarov🇩🇪 · I. N. Mishustin🇩🇪 · M. I. Gorenstein🇺🇦 · V. I. Zhdanov🇺🇦

   We study self-gravitating multi-pion systems (pion stars) in a state of the Bose condensate. To ensure stability of such stars, it is assumed that they are immersed in the lepton background. Two different phenomenological equations of state (EoS) for the pion matter are used, some of them having the first order phase transition. The model parameters are chosen to reproduce the recent lattice QCD data at zero temperature and large isospin chemical potential. It is shown that the mass-radius diagrams of pion stars obtained with phenomenological EoS are close to ones calculated in the ideal gas model. We analyze properties of neutrino clouds which are necessary for stabilizing the pion stars.

   hep-phgr-qcPRD(2023)·9 citations
2. 02*

   Magnetic field imaging by cosmic-ray muons (Magic-$\mu$) -- First feasibility simulation for strong magnetic fields

   Tadahiro Kin🇯🇵 · Hamid Basiri🇯🇵 · Eduardo Cortina Gil🇧🇪 · Andrea Giammanco🇧🇪

   We have proposed a novel application for cosmic-ray muography, called Magic-$\mu$, which is short for Magnetic field Imaging by Cosmic-ray Muons. The general goal of Magic-$\mu$ is to detect the presence of a magnetic field or magnetic flux density whose three-dimensional distribution is unknown. Depending on the application, Magic-$\mu$ can have three detection modes. The first is "magnetic field imaging," which is detecting the presence of a magnetic field in specific voxels within a region of space. The other two modes, transmission and deflection, aim not only to detect the presence but also to measure the flux density of the magnetic field. We have performed a feasibility study using the PHITS Monte Carlo simulation code, for strong and weak magnetic fields. In this paper, we first give an overview of the concept and basic principles of magnetic field muography. Then, the results of the feasibility study on magnetic field imaging for a strong magnetic field (more than 500 mT) are presented.

   hep-phastro-ph.IMhep-exJAIS(2023)·0 citations
3. 03*

   CP Asymmetry in $\tau \to K\pi {\nu }_{\tau }$ within Non-Minimal $SU(5)$

   Gaber Faisel🇹🇷 · S. Khalil🇪🇬

   Direct CP asymmetry in semi-leptonic $\tau$ decays is an intriguing hint for new physics beyond the standard model. We investigate the CP asymmetry in ${\tau }^{-}\to K_S^0{\pi }^{-}{\nu }_{\tau }$ and ${\tau }^{-}\to K^{-}{\pi }^0{\nu }_{\tau }$ decays in non-minimal SU(5) model, with 45-dimensional Higgs multiplet. We show that the associate color-triplet scalar is a natural example of a scalar leptoquark that mediates the transition $\tau \to s\bar{u}{\nu }_{\tau }$, and accounts for the 2.8 $\sigma$ discrepancy between the $A_{\mathrm{CP}}({\tau }^{-}\to K_S^0{\pi }^{-}{\nu }_{\tau })$ experimental results and the SM expectation. Furthermore, it predicts a sizable $A_{\mathrm{CP}}({\tau }^{-}\to K^{-}{\pi }^0{\nu }_{\tau })$, of order $\mathcal{O}(10^{-3})$, which can be accessible in current and near future experiments.

   hep-phJHEP(2023)·2 citations
4. 04*

   Recent progress on the nonlocal power corrections to the inclusive penguin decays $\bar{B}\to X_s\gamma$ and $\bar{B}\to X_s\ell \ell$

   Michael Benzke (DESY)🇩🇪 · Tobias Hurth (JGU Mainz)🇩🇪

   We report on recent progress in the field of nonlocal (so-called resolved) contributions to the inclusive penguin decays which presently belong to the largest uncertainties in these inclusive decay modes. There is still a very large scale and a large charm mass dependence in the present leading order results which can in the future be decreased by including the ${\alpha }_s$ corrections.

   hep-phFrascati Phys.Ser.(2022)·4 citations
5. 05*

   Implications on Cosmology from Dirac Neutrino Magnetic Moments

   E. Grohs🇺🇸 · A. B. Balantekin🇺🇸

   The mechanism for generating neutrino masses remains a puzzle in particle physics. If neutrino masses follow from a Dirac mass term, then neutrino states exist with opposite chirality compared to their weakly-interacting counterparts. These inactive states do not interact with their active counterparts at measurable scales in the standard model. However, the existence of these states can have implications for cosmology as they contribute to the radiation energy density at early times, and the matter energy density at late times. How Dirac neutrinos may populate thermal states via an anomalous magnetic moment operator is the focus of this work. A class of models where all neutrinos have a magnetic moment independent of flavor or chirality is considered. Subsequently, the cross sections for neutrinos scattering on background plasma particles are calculated so that the relic inactive neutrino energy is derived as a function of plasma temperature. To do so, one needs cross sections for scattering on all electrically charged standard-model particles. Therefore, the scattering cross section between a neutrino and $W$-boson via the magnetic moment vertex is derived. Current measurements put a constraint on the size of the neutrino magnetic moment from the cosmological parameter $N_{\mathrm{eff}}$ and light-element primordial abundances. Finally, how the extra Dirac states contribute to the matter energy density at late times is investigated by examining neutrino free-streaming.

   hep-phastro-ph.COPRD(2023)·9 citations
6. 06*

   Investigating the elliptic anisotropy of identified particles in p--Pb collisions with a multi-phase transport model

   Siyu Tang🇨🇳 · Liang Zheng🇨🇳 · Xiaoming Zhang🇨🇳 · Renzhuo Wan🇨🇳

   The elliptic azimuthal anisotropy coefficient ($v_2$) of the identified particles at midrapidity ($|\eta |<0.8$) was investigated in p--Pb collisions at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV using a multi-phase transport model (AMPT). The calculations of differential $v_2$ based on the advanced flow extraction method of light flavor hadrons (pions, kaons, protons, and $\Lambda$) in small collision systems were extended to a wider transverse momentum ($p_{\mathrm{T}}$) range of up to 8 GeV/$c$ for the first time. The string-melting version of the AMPT model provides a good description of the measured $p_{\mathrm{T}}$-differential $v_2$ of the mesons but exhibits a slight deviation from the baryon $v_2$. In addition, we observed the features of mass ordering at low $p_{\mathrm{T}}$ and the approximate number of constituent quarks (NCQ) scaled at intermediate $p_{\mathrm{T}}$. Moreover, we demonstrate that hadronic rescattering does not have a significant impact on $v_2$ in p--Pb collisions for different centrality selections, whereas partonic scattering dominates in generating the elliptic anisotropy of the final particles. This study provides further insight into the origin of collective-like behavior in small collision systems and has referential value for future measurements of azimuthal anisotropy.

   hep-phNucl.Sci.Tech.(2024)·18 citations
7. 07*

   Non-Minimal Approximation for the Type-I Seesaw Mechanism

   Mikhail Dubinin🇷🇺 · Elena Fedotova🇷🇺

   A non-minimal approximation for effective masses of light and heavy neutrinos in the framework of a type-I seesaw mechanism with three generations of sterile Majorana neutrinos which recover the symmetry between quarks and leptons is considered. The main results are: (a) the next-order corrections to the effective mass matrix of heavy neutrinos due to terms O({\theta}MD) are obtained, which modify the commonly used representation for the effective mass (MD is a Dirac neutrino mass when the electroweak symmetry is spontaneously broken); and (b) the general form of the mixing matrix is found in non-minimal approximation parametrized by a complex 3x3 matrix satisfying a nontrivial constraint. Numerical analysis within the {\nu}MSM framework demonstrates the very small effect of new contributions of direct collider observables as opposed to their possible significance for cosmological models.

   hep-phastro-ph.COSymmetry(2023)·6 citations
8. 08*

   High energy nuclear physics meets Machine Learning

   Wan-Bing He🇨🇳 · Yu-Gang Ma🇨🇳 · Long-Gang Pang🇨🇳 · Huichao Song🇨🇳 · Kai Zhou🇩🇪

   Though being seemingly disparate and with relatively new intersection, high energy nuclear physics and machine learning have already begun to merge and yield interesting results during the last few years. It's worthy to raise the profile of utilizing this novel mindset from machine learning in high energy nuclear physics, to help more interested readers see the breadth of activities around this intersection. The aim of this mini-review is to introduce to the community the current status and report an overview of applying machine learning for high energy nuclear physics, to present from different aspects and examples how scientific questions involved in high energy nuclear physics can be tackled using machine learning.

   hep-phhep-exnucl-exnucl-thNucl.Sci.Tech.(2023)·105 citations
9. 09*

   New solar X-ray constraints on keV Axion-Like Particles

   Cyprien Beaufort🇫🇷 · Mar Bastero-Gil🇪🇸 · Tiffany Luce🇫🇷 · Daniel Santos🇫🇷

   The decay of Axion-Like Particles (ALPs) trapped in the solar gravitational field would contribute to the observed solar X-ray flux, hence constraining ALP models. We improve by one order of magnitude the existing limits in the parameter space $(g_{a\gamma \gamma },m)$ by considering ALPs production via photon coalescence. For $g_{ae}\ne 0$, we demonstrate that trapped ALPs can be Compton-absorbed while crossing the Sun, resulting in two regimes in the exclusion limits, with a transition triggered by $g_{ae}$. Out of the transitional region, the solar X-ray constraints on ALPs are exclusively governed by $g_{a\gamma \gamma }$.

   hep-phastro-ph.SRPRD(2023)·21 citations
10. 10*

    Compositeness of $T_{cc}$ and $X(3872)$ by considering decay and coupled-channels effects

    Tomona Kinugawa🇯🇵 · Tetsuo Hyodo🇯🇵

    The compositeness of weakly bound states is discussed using the effective field theory from the viewpoint of the low-energy universality. We introduce a model with coupling of the single-channel scattering to the bare state, and study the compositeness of the bound state by varying the bare state energy. In contrast to the naive expectation that the near-threshold states are dominated by the molecular structure, we demonstrate that a non-composite state can always be realized even with a small binding energy. At the same time, however, it is shown that a fine tuning is necessary to obtain the non-composite weakly bound state. In other words, the probability of finding a model with the composite dominant state becomes larger with the decrease of the binding energy in accordance with the low-energy universality. For the application to exotic hadrons, we then discuss the modification of the compositeness due to the decay and coupled-channels effects. We quantitatively show that these contributions suppress the compositeness, because of the increase of the fraction of other components. Finally, as examples of near-threshold exotic hadrons, the structures of $T_{cc}$ and $X(3872)$ are studied by evaluating the compositeness. We find the importance of the coupled-channels and decay contributions for the structures of $T_{cc}$ and $X(3872)$, respectively.

    hep-phnucl-thPRC(2024)·38 citations
11. 11*

    Probing generalized neutrino interactions with the DUNE Near Detector

    Pantelis Melas🇬🇷 · Dimitrios K. Papoulias🇬🇷 · Niki Saoulidou🇬🇷

    We explore the prospects of constraining general non standard interactions involving light mediators through elastic neutrino-electron scattering events at the DUNE Near Detector (ND). We furthermore consider the special cases of light vector mediators in motivated models such as $U(1{)}_{B-L}$, $U(1{)}_{L_{\mu }-L_{\tau }}$, $E_6$ and left-right symmetry. The present analysis is based on detailed Monte Carlo simulations of the expected DUNE-ND signal taking into account detector resolution effects, realistic backgrounds as well as On-Axis and Off-Axis neutrino spectra. We show that the high intensity neutrino beam available at Fermilab can place competitive constraints surpassing those of low-energy neutrino searches and direct detection dark matter experiments.

    hep-phJHEP(2023)·15 citations
12. 12*

    Theory prediction in PDF fitting

    Andrea Barontini🇮🇹 · Alessandro Candido🇮🇹 · Juan M. Cruz-Martinez🇨🇭 · Felix Hekhorn🇮🇹 · Christopher Schwan🇩🇪

    Continuously comparing theory predictions to experimental data is a common task in analysis of particle physics such as fitting parton distribution functions (PDFs). However, typically, both the computation of scattering amplitudes and the evolution of candidate PDFs from the fitting scale to the process scale are non-trivial, computing intesive tasks. We develop a new stack of software tools that aim to facilitate the theory predictions by computing FastKernel (FK) tables that reduce the theory computation to a linear algebra operation. Specifically, I present PineAPPL, our workhorse for grid operations, EKO, a new DGLAP solver, and yadism, a new DIS library. Alongside, I review several projects that become available with the new tools.

    hep-phJ.Phys.Conf.Ser.(2026)·1 citation
13. 13*

    An $SU(5)\times U(1{)}^{\prime }$ SUSY GUT with a "vector-like chiral" fourth family to fit all low energy data, including the muon $g-2$

    Harshal Kulkarni🇮🇳 · Stuart Raby🇺🇸

    An additional generation of quarks and leptons and their SUSY counterparts, which are vector-like under the Standard Model gauge group but are chiral with respect to the new U(1)${}_{3-4}$ gauge symmetry, are added to the Minimal Supersymmetric Standard Model (MSSM). We show that this model is a GUT and unifies the three SM gauge couplings and also the additional U(1)${}_{3-4}$ coupling at a GUT scale of $\approx 5\times 10^{16}$ GeV and explains the experimentally observed deviation of the muon $g-2$. We also fit the quark flavor changing processes consistent with the latest experimental data and look at the effect of the new particles on the $W$ boson mass without obviously conflicting with the observed masses of particles, CKM matrix elements, neutrino mixing angles, their mass differences, and the lepton-flavor violating bounds. This model predicts sparticle masses less than 25 TeV, with a gluino mass $\approx 2.3-3$ TeV consistent with constraints, and one of the neutralinos as the LSP with a mass of $\approx 480-580$ GeV, which is a potential dark matter candidate. The model is string theory motivated and predicts the VL quarks, leptons, a massive $Z^{\prime }$ and two Dirac neutrinos at the TeV scale and the branching ratios of $\mu ⟶e\gamma$, $\tau ⟶\mu \gamma$ and $\tau ⟶3\mu$ with BR($\mu ⟶e\gamma$) within reach of future experiments.

    hep-phJHEP(2023)·3 citations
14. 14*

    Three-loop matching coefficients for heavy flavor-changing currents and the phenomenological applications

    Wei Tao🇨🇳 · Zhen-Jun Xiao🇨🇳 · Ruilin Zhu🇨🇳

    Within the framework of non-relativistic QCD (NRQCD) factorization, we compute the matching coefficients between full Quantum Chromodynamics (QCD) and NRQCD for the heavy flavor-changing vector, axial-vector, scalar and pseudo-scalar currents up to next-to-next-to-next-to-leading order (N${}^3$LO). We accomplish the analytical expressions for the three-loop renormalization constants and the corresponding anomalous dimensions for all of the four NRQCD currents with two different heavy flavors. The three-loop QCD corrections to the matching coefficients turn out to be significantly larger than lower order corrections. By employing the scale relation, we obtain the N${}^3$LO corrections to the wave functions at the origin for the vector $B_c^{\ast }$ meson and the pseudo-scalar $B_c$ meson from the known result for the equal-mass heavy quarkonium in potential NRQCD (pNRQCD). We find large cancellations at the third order between the matching coefficients and the wave functions at the origin, and obtain the convergent decay constants of $B_c^{\ast }$ and $B_c$ up to N${}^3$LO. We present the complete perturbative QCD predictions for the decay constants, leptonic decay widths, and branching ratios of the beauty-charmed mesons.

    hep-phJHEP(2023)·10 citations
15. 15*

    Isocurvature Constraints on Scalar Dark Matter Production from the Inflaton

    Marcos A. G. Garcia🇲🇽 · Mathias Pierre🇩🇪 · Sarunas Verner🇺🇸

    We investigate the production of a spectator scalar dark matter field that is directly coupled to the inflaton during inflation and reheating. We consider two specific inflationary potentials, namely the Starobinsky and T-model of inflation, which satisfy the constraints on the scalar tilt, $n_s$, and tensor-to-scalar ratio, $r$, measured by the Planck satellite. Excitation of light scalar dark matter during inflation may result in large isocurvature perturbations, which can be avoided by inducing a sizable effective dark matter mass during the inflationary phase. For purely gravitational production, the Planck isocurvature constraints require the dark matter mass to be larger than the Hubble scale at horizon exit, with $m_{\chi }\gtrsim 0.5H_{\ast }$. For small bare dark matter masses $m_{\chi }\ll H_{\ast }$, these constraints translate into a lower bound on the dark matter coupling to the inflaton. We argue that these constraints can be applied to a wide class of single-field slow-roll inflation models. We also derive isocurvature, dark matter abundance, and Lyman-$\alpha$ constraints on the direct coupling and bare dark matter mass.

    hep-phastro-ph.COgr-qcPRD(2023)·37 citations
16. 16*

    Fast and accurate AMS-02 antiproton likelihoods for global dark matter fits

    Sowmiya Balan🇩🇪 · Felix Kahlhoefer🇩🇪 · Michael Korsmeier🇸🇪 · Silvia Manconi🇩🇪 · Kathrin Nippel🇩🇪

    The antiproton flux measurements from AMS-02 offer valuable information about the nature of dark matter, but their interpretation is complicated by large uncertainties in the modeling of cosmic ray propagation. In this work we present a novel framework to efficiently marginalise over propagation uncertainties in order to obtain robust AMS-02 likelihoods for arbitrary dark matter models. The three central ingredients of this framework are: the neural emulator DarkRayNet, which provides highly flexible predictions of the antiproton flux; the likelihood calculator pbarlike, which performs the marginalisation, taking into account the effects of solar modulation and correlations in AMS-02 data; and the global fitting framework GAMBIT, which allows for the combination of the resulting likelihood with a wide range of dark matter observables. We illustrate our approach by providing updated constraints on the annihilation cross section of WIMP dark matter into bottom quarks and by performing a state-of-the-art global fit of the scalar singlet dark matter model, including also recent results from direct detection and the LHC.

    hep-phastro-ph.COastro-ph.HEJCAP(2023)·16 citations
17. 17*

    Learning the language of QCD jets with transformers

    Thorben Finke🇩🇪 · Michael Krämer🇩🇪 · Alexander Mück🇩🇪 · Jan Tönshoff🇩🇪

    Transformers have become the primary architecture for natural language processing. In this study, we explore their use for auto-regressive density estimation in high-energy jet physics, which involves working with a high-dimensional space. We draw an analogy between sentences and words in natural language and jets and their constituents in high-energy physics. Specifically, we investigate density estimation for light QCD jets and hadronically decaying boosted top jets. Since transformers allow easy sampling from learned densities, we exploit their generative capability to assess the quality of the density estimate. Our results indicate that the generated data samples closely resemble the original data, as evidenced by the excellent agreement of distributions such as particle multiplicity or jet mass. Furthermore, the generated samples are difficult to distinguish from the original data, even by a powerful supervised classifier. Given their exceptional data processing capabilities, transformers could potentially be trained directly on the massive LHC data sets to learn the probability densities in high-energy jet physics.

    hep-phJHEP(2023)·46 citations
18. 18*

    Dark matter from hot big bang black holes

    Avi Friedlander🇨🇦 · Ningqiang Song🇨🇳 · Aaron C. Vincent🇨🇦

    If the temperature of the hot thermal plasma in the Early Universe was within a few orders of magnitude of the Planck scale $M_{\mathrm{Pl}}$, then the hoop conjecture predicts the formation of microscopic black holes from particle collisions in the plasma. Although these evaporated instantly, they would have left behind a relic abundance of all stable degrees of freedom which couple to gravity. Here we show that, upon minimal assumptions of a high reheat temperature and semiclassical black hole dynamics, this process could have produced the relic abundance of dark matter observed today for a particle mass anywhere in the range of $100\mathrm{keV}\lesssim m_{dm}<M_{\mathrm{Pl}}$, though it could be subdominant to graviton-mediated freeze-in above $m_{dm}\sim$ MeV. The production mechanism does not rely on any additional assumptions about non-gravitational dark matter-Standard Model interaction.

    hep-phastro-ph.COgr-qcPRD(2023)·7 citations
19. 19*

    Dark Matter Cosmology with Varying Viscosity: a Possible Resolution to the $S_8$ Tension

    Amjad Ashoorioon🇮🇷 · Zahra Davari🇮🇷

    We study varying forms of viscous dark matter and try to address the intriguing tensions of the standard model of cosmology with recent cosmological data, including the Hubble and $S_8$ tensions. We note that by assuming the dark matter viscosity depends on the Hubble parameter, dark matter density, or both, one can improve the statistics. Although the models tend to aggravate the Hubble tension a bit, they tend to reduce the $S_8$ tension, even in comparison with the constant viscosity case. Since similar to viscosity massive neutrinos suppress the power spectrum of matter on small length scales, considering them along with the viscous dark matter, we find that the neutrino mass range is tightened.

    ↳ astro-ph.COgr-qchep-phhep-thApJ(2023)·16 citations
20. 20*

    Single-Particle Spectra in Relativistic Heavy-Ion Collisions Within the Thermal Quantum Field Theory

    Dmitry Anchishkin🇺🇦

    A quantum generalization of the Cooper-Fry recipe is proposed. The single-particle spectrum arising from relativistic collisions of particles and nuclei is calculated within the thermal quantum field theory framework. The starting point of consideration is the solution of the initial-value problem of particle emission from a space-like hypersurface. In the following steps, we obtain the single-particle spectrum using the ``smaller'' Green's function associated with the fireball medium. Based on this result, several specific examples of particle emission are considered.

    ↳ nucl-thhep-phquant-phJ.Phys.G(2022)·1 citation
21. 21*

    $S_8$ increases with effective redshift in $\Lambda$CDM cosmology

    Shahnawaz A. Adil🇮🇳 · Özgür Akarsu🇹🇷 · Mohammad Malekjani🇮🇷 · Eoin Ó Colgáin🇮🇪 · Saeed Pourojaghi🇮🇷 · Anjan A. Sen🇮🇳 · M. M. Sheikh-Jabbari🇮🇷

    Hubble constant $H_0$ and weighted amplitude of matter fluctuations $S_8$ determinations are biased to higher and lower values, respectively, in the late Universe with respect to early Universe values inferred by the Planck collaboration within flat $\Lambda$CDM cosmology. If these anomalies are physical, i.e. not due to systematics, they naively suggest that $H_0$ decreases and $S_8$ increases with effective redshift. Here, subjecting matter density today ${\Omega }_m$ to a prior, corresponding to a combination of Planck CMB and BAO data, we perform a consistency test of the Planck-$\Lambda$CDM cosmology and show that $S_8$ determinations from $f{\sigma }_8(z)$ constraints increase with effective redshift. Due to the redshift evolution, a $\sim 3\sigma$ tension in the $S_8$ parameter with Planck at lower redshifts remarkably becomes consistent with Planck within $1\sigma$ at high redshifts. This provides corroborating support for an $S_8$ discrepancy that is physical in origin. We further confirm that the flat $\Lambda$CDM model is preferred over a theoretically ad hoc model with a jump in $S_8$ at a given redshift. In the absence of the CMB+BAO ${\Omega }_m$ prior, we find that $>3\sigma$ tensions with Planck in low redshift data are ameliorated by shifts in the parameters in high redshift data. Results here and elsewhere suggest that the $\Lambda$CDM cosmological parameters are redshift dependent. Fitting parameters that evolve with redshift is a recognisable hallmark of model breakdown.

    ↳ astro-ph.COhep-phhep-thMNRAS(2023)·61 citations
22. 22*

    Inelastic Exponentiation and Classical Gravitational Scattering at One Loop

    Alessandro Georgoudis🇸🇪 · Carlo Heissenberg🇸🇪 · Ingrid Vazquez-Holm🇸🇪

    We calculate the inelastic $2\to 3$ one-loop amplitude for the scattering of two point-like, spinless objects with generic masses involving the additional emission of a single graviton. We focus on the near-forward, or classical, limit. Our results include the leading and subleading orders in the soft-region expansion, which captures all non-analytic contributions in the transferred momentum and in the graviton's frequency. This allows us to check the first constraint arising from the inelastic exponentiation put forward in Refs. 2107.12891, 2112.07556, 2210.12118 and to calculate the $2\to 3$ one-loop matrix element of the $N$-operator, linked to the $S$-matrix by $S=e^{iN}$, showing that it is real, classical and free of infrared divergences. We discuss how our results feature in the calculation of the $\mathcal{O}(G^3)$ corrections to the asymptotic waveform.

    ↳ hep-thgr-qchep-phJHEP(2023)·109 citations
23. 23*

    Aspects of the Electroweak Skyrmion

    Stefano Bolognesi🇮🇹 · Sven Bjarke Gudnason🇨🇳 · Giacomo Santoni🇮🇹

    We consider certain aspects of the electroweak Skyrmion (EWS). We discuss the case of EWS with dynamical Higgs and find numerical solutions for various values of the cutoff scale. Our results are qualitatively similar to the ones present in the literature, but we find a considerable lower mass than previous studies. We discuss the quantization of the light degrees of freedom and prove that the EWS is a boson. We consider the interaction between fermions and the EWS and the transfer of fermionic charge onto the soliton. We consider the large distance structure of the soliton and the interaction between two well separated EWSs. We find that the classical EWS has a magnetic dipole moment. We discuss the lifetime of the metastable soliton. Finally, we discuss some phenomenological and cosmological consequences of our results.

    ↳ hep-thhep-phJHEP(2023)·1 citation
24. 24*

    Extremal Kerr black holes as amplifiers of new physics

    Gary T. Horowitz🇺🇸 · Maciej Kolanowski🇵🇱 · Grant N. Remmen🇺🇸 · Jorge E. Santos🇬🇧

    We show that extremal Kerr black holes are sensitive probes of new physics. Stringy or quantum corrections to general relativity are expected to generate higher-curvature terms in the gravitational action. We show that in the presence of these terms, asymptotically flat extremal rotating black holes have curvature singularities on their horizon. Furthermore, near-extremal black holes can have large yet finite tidal forces for infalling observers. In addition, we consider five-dimensional extremal charged black holes and show that higher-curvature terms can have a large effect on the horizon geometry.

    ↳ hep-thastro-ph.HEgr-qchep-phPRL(2023)·91 citations
25. 25*

    Exotic energy injection in the early universe I: a novel treatment for low-energy electrons and photons

    Hongwan Liu🇺🇸 · Wenzer Qin🇺🇸 · Gregory W. Ridgway🇺🇸 · Tracy R. Slatyer🇺🇸

    Decaying or annihilating dark matter and other exotic energy injections can modify the spectrum of the universe's photon bath, resulting in e.g. new contributions to spectral distortions of the cosmic microwave background blackbody spectrum and modifications to the temperature and ionization history of the universe. Here, we present an improved version of the $\text{DarkHistory}$ code, which is now capable of consistently calculating the spectrum of low-energy photons by properly treating the interactions of these photons with the levels of hydrogen atoms. Other changes to the code include a more detailed treatment of energy deposition by low-energy electrons, and spectral distortions from heating of the intergalactic medium. All of the improvements we have made to $\text{DarkHistory}$ are publicly available.

    ↳ astro-ph.COhep-phPRD(2023)·34 citations
26. 26*

    Exotic energy injection in the early universe II: CMB spectral distortions and constraints on light dark matter

    Hongwan Liu🇺🇸 · Wenzer Qin🇺🇸 · Gregory W. Ridgway🇺🇸 · Tracy R. Slatyer🇺🇸

    We calculate the post-recombination contribution to the Cosmic Microwave Background (CMB) spectral distortion due to general exotic energy injections, including dark matter (DM) decaying or annihilating to Standard Model particles. Upon subtracting the background distortion that would be present even without such energy injections, we find residual distortions that are still potentially large enough to be detectable by future experiments such as PIXIE. The distortions also have a high-energy spectral feature that is a unique signature of the injection of high-energy particles. We present a calculation of the global ionization history in the presence of decaying dark matter with sub-keV masses, and also show that previous calculations of the global ionization history in the presence of energy injection are not significantly modified by these additional spectral distortions. Our improved treatment of low-energy electrons allows us to extend calculations of the CMB anisotropy constraints for decaying DM down to arbitrarily low masses. We also recast these bounds as constraints on the coupling of axion-like particles to photons.

    ↳ astro-ph.COhep-phPRD(2023)·60 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.