Fri·Sep 12, 2025Friday·September 12, 2025

1. 01*

   Microscopic calculation of two-particle-two-hole meson-exchange currents in ${}^{40}$Ar and asymmetric scaling properties for neutrino and electron scattering

   V.L. Martinez-Consentino🇪🇸 · J. Segovia🇪🇸 · J.E. Amaro🇪🇸

   We present a microscopic calculation of two particle-two hole meson exchange current response functions in asymmetric nuclei, with particular emphasis on the ${}^{40}$Ar nucleus. Employing a relativistic mean-field and relativistic Fermi gas framework, we compute the nuclear response for ${}^{40}$Ar and compare it with that of the symmetric ${}^{40}$Ca nucleus, analyzing the role of proton-neutron imbalance. The model incorporates distinct proton and neutron Fermi momenta to accurately capture the nuclear dynamics of systems with $Z\ne N$. Our results indicate that using ${}^{40}$Ca as a proxy for ${}^{40}$Ar leads to a systematic error of approximately 10\%. Additionally, we propose an asymmetric scaling formula to obtain the 2p2h response for arbitrary nuclei from the ${}^{12}$C response, improving the description of asymmetric nuclei. Finally, we benchmark our predictions against inclusive electron scattering and neutrino cross sections.

   hep-phnucl-thPRD(2025)·3 citations
2. 02*

   Constraining Dark Photon Dark Matter with Radio Silence from Soliton Mergers around Supermassive Black Holes

   Dorian W. P. Amaral🇺🇸 · Enrico D. Schiappacasse🇨🇱 · Hong-Yi Zhang🇨🇳

   We place the first constraints on the dark matter fraction contained within dark photon solitons using the absence of their predicted radio-frequency signatures, or radio silence, following mergers around supermassive black holes. In these dense environments, spiky dark matter density profiles can form that enhance the soliton merger rate. We present a novel estimate of this rate by incorporating both the steepened dark matter profile and the soliton velocity dispersion via the Jeans equation. For galaxies with an initial profile ${\rho }_{\mathrm{DM}}\propto r^{-1}$, we find the total merger rate across redshifts $0\le z\le 4$ to be ${\Gamma }_{\text{merg}}^{\text{TOTAL}}\lesssim 10^{-7}{f}_{\text{DM}}^2{\text{Mpc}}^{-3}{\text{day}}^{-1}$, where $f_{\mathrm{DM}}$ is the solitonic fraction of dark matter. This enhanced rate leads to more major merger events in which the generated soliton has a mass exceeding a critical threshold, leading to its decay via the parametric resonance phenomenon that produces brief, narrowband, and energetic radio bursts detectable by fast radio burst surveys. Comparing our predictions with the non-observation of such events, we already obtain $f_{\mathrm{DM}}\lesssim 10^{-1}$ from the first fast radio burst study. This constraint is strengthened to $f_{\mathrm{DM}}\lesssim 10^{-2}$ from the Parkes HTRU survey, with CHIME projected to tighten this to $f_{\mathrm{DM}}\lesssim 10^{-3}$. For larger $f_{\mathrm{DM}}$, we instead constrain the effective coupling strength between the dark and visible sectors to lie outside $10^{-18}\mathrm{Ge}{\mathrm{V}}^{-1}\lesssim g\lesssim 10^{-8}\mathrm{Ge}{\mathrm{V}}^{-1}$ for dark photon masses in the range $10^{-6}\mathrm{eV}\lesssim m\lesssim 10^{-4}\mathrm{eV}$. Our results establish astrophysical transients as powerful probes of dark sectors, opening a window onto the detectability of ultralight vector fields.

   hep-phastro-ph.COastro-ph.HEJCAP(2026)·4 citations
3. 03*

   Production of heavy tetraquarks in rare exclusive decays of the Higgs boson

   F. A. Martynenko🇷🇺 · A. V. Eskin🇷🇺 · A. P. Martynenko🇷🇺

   The relativistic quark model is used to study the processes of heavy tetraquark $(cc\bar{c}\bar{c})$ production in the Higgs boson decay. We consider quark-gluon, ZZ-boson, and quark-gluon loop decay mechanisms with the production of a fully charmed tetraquark. Relativistic interaction amplitudes are constructed and decay widths are calculated taking into account relativistic corrections in the decay amplitude connected with the relative motion of quarks and antiquarks.

   hep-phPRD(2025)·2 citations
4. 04*

   Renormalon-based resummation for spacelike and timelike QCD quantities whose perturbation expansion has general form

   Cesar Ayala🇨🇱 · Gorazd Cvetič🇨🇱 · Reinhart Kögerler🇩🇪

   We present a generalisation of our previous approach of a renormalon-motivated resummation of the QCD observables. Previously it was applied to the spacelike observables whose perturbation expansion was $D(Q^2)=a(Q^2)+O(a^2)$, where $a(Q^2)\equiv {\alpha }_s(Q^2)/\pi$ is the running QCD coupling. Now we generalise the resummation to spacelike quantities $D(Q^2)=a(Q^2{)}^{{\nu }_0}+O(a^{{\nu }_0+1})$ and timelike quantities $F(\sigma )=a(\sigma {)}^{{\nu }_0}+O(a^{{\nu }_0+1})$, where ${\nu }_0$ is in general a noninteger number ($0<{\nu }_0\le 1$). We evaluate with this approach a timelike quantity, namely the scheme-invariant factor of the Wilson coefficient of the chromomagnetic operator in the heavy-quark effective Lagrangian, and related quantities.

   hep-phhep-thJ.Phys.G(2026)·3 citations
5. 05*

   R-parity violation and 8 TeV four-jet events at the LHC

   Pedro Bittar🇧🇷 · Subhojit Roy🇺🇸 · Carlos E.M. Wagner🇺🇸

   The CMS Collaboration at the Large Hadron Collider (LHC) has observed two four-jet events with a total invariant mass of about 8 TeV; within each event, the jets can be paired into two dijets with invariant masses of 2 TeV each. These are extremely rare events due to the large invariant mass, which implies a very small QCD background, as well as to the di-jet structure, which makes it prone to an interpretation in terms of a heavy resonance decaying into two lighter ones. We investigate the possible interpretation of these events in terms of supersymmetry with a single baryon-number and R-Parity violating term. In this particular scenario, the lighter resonances are identified with the right-handed squarks of the first generation, while the heavy one is interpreted in terms of a down-squark of the second or third generation. We discuss the constraints that shape this interpretation and outline a well-defined scenario for its realization. The resulting predictions can be scrutinized with forthcoming LHC data.

   hep-phhep-exPRD(2025)·4 citations
6. 06*

   Tree-level NLO corrections to inclusive ${\psi }^{\prime }$ production in High Energy Factorization

   A.A. Prokhorov🇷🇺 · S.P. Baranov🇷🇺 · A.V. Lipatov🇷🇺 · M.A. Malyshev🇷🇺 · X. Chen🇨🇳

   We consider inclusive $\psi (2S)$ production in proton-proton collisions at collider energies in the framework of non-relativistic QCD and high-energy factorization beyond the low-order approximation. We utilise a matching scheme proposed earlier to merge the leading order and tree-level next-to-leading order production amplitudes and now extend it to low transverse momenta and/or forward rapidities. With the improved scheme, we examine the possibility to simultaneously describe all unpolarized LHC data in the full kinematic range accessible to experimental measurements and try different Transverse Momentum Dependent (TMD) gluon distributions in the proton. A global fit to the data is carried out to extract the color octet long-distance matrix elements for $\psi (2S)$ mesons. We show that taking the NLO corrections into account leads to better description of the data.

   hep-phPRD(2025)·2 citations
7. 07*

   Dark Vector Boson Bremsstrahlung: New Form Factors for a Broader Class of Models

   Felix Kling🇩🇪 · Peter Reimitz🇧🇷 · Adam Ritz🇨🇦

   We explore the sensitivity of collider experiments to a broad class of GeV-scale dark vector models of new physics via production in proton and neutron bremsstrahlung and initial state radiation. This is achieved using a new physically motivated model for timelike vector form factors with generic charges for both protons and neutrons, which is fit to a variety of timelike and spacelike data with quantified uncertainties. The production model for both proton and neutron bremsstrahlung is applied to re-cast and extend the reach of existing FASER data to GeV-mass dark photons, $U(1{)}_B$, $U(1{)}_{B-L}$, and photophobic vectors, as well as forecasts for millicharged particles at FORMOSA.

   hep-phPRD(2026)·10 citations
8. 08*

   Casimir scaling in glueballs in SU($N$) and Sp($2N$) gauge theories: hints from constituent approaches

   F. Buisseret🇧🇪 · C. Chevalier🇧🇪 · V. Mathieu🇪🇸 · C. Semay🇧🇪

   We show that the lattice glueball masses $M_G$ versus $N$ in SU($N$) and Sp($2N$) Yang-Mills theories scale as $\frac{M_G}{\sqrt{\sigma }}\sim \sqrt{\frac{C_2(adj)}{C_2(f)}}$, with $\sigma$ the fundamental string tension and $C_2(adj)$ and $C_2(f)$ the quadratic Casimir of the gauge algebra in the adjoint and fundamental representations. This scaling behaviour is followed by the great majority of available lattice glueball states, and may set constraints on $SU(3)$ models by imposing a specific behaviour at $N\ne 3$. The observed scaling is compatible with two assumptions: (1) The glueball masses are proportional to the square root of the adjoint string tension, $M_G\sim {\sqrt{\sigma }}_{adj}$; (2) The string tension follows the Casimir scaling, i.e. ${\sigma }_{adj}=\frac{C_2(adj)}{C_2(f)}\sigma$. In a constituent gluon picture, our results suggest a low-lying glueball spectrum made of two transverse constituent gluons bound by an adjoint string, completed by three transverse constituent gluons bound by a Y-junction of adjoint strings rather than a $\Delta -$shaped junction of fundamental strings.

   hep-phhep-lathep-thPLB(2026)·1 citation
9. 09*

   $CP$ asymmetries in the ${\Lambda }_c^{+}\to p{K}_S^0$ and ${\Xi }_c^{+}\to {\Sigma }^{+}{K}_S^0$ decays

   Di Wang🇨🇳 · Si-Jia Wen🇨🇳

   $CP$ asymmetry is a crucial element in interpreting the matter-antimatter asymmetry in the universe and searching for new physics beyond the Standard Model. In this work, we study the $CP$ asymmetries in the ${\Lambda }_c^{+}\to p{K}_S^0$ and ${\Xi }_c^{+}\to {\Sigma }^{+}{K}_S^0$ decays. The time-independent and time-integrated $\Gamma$-, $\alpha$-, $\beta$-, and $\gamma$-defined $CP$ asymmetries in the chain decay ${\mathcal{B}}_{c\overline{3}}\to \mathcal{B}K(t)(\to {\pi }^{+}{\pi }^{-})$ are derived. It is found that the $CP$ asymmetry in $K^0-{\overline{K}}^0$ mixing cancels out in the $\alpha$-, $\beta$-, and $\gamma$-defined $CP$ asymmetries. The $U$-spin analysis shows that the amplitudes of the ${\Lambda }_c^{+}\to p{K}^0$, ${\Lambda }_c^{+}\to p{\overline{K}}^0$, ${\Xi }_c^{+}\to {\Sigma }^{+}{K}^0$, and ${\Xi }_c^{+}\to {\Sigma }^{+}{\overline{K}}^0$ modes are not independent. The hadronic parameters determining $CP$ asymmetries in the ${\Lambda }_c^{+}\to p{K}_S^0$ and ${\Xi }_c^{+}\to {\Sigma }^{+}{K}_S^0$ decays could be extracted from the $K_S^0-K_L^0$ asymmetry and decay parameters $\alpha$, $\beta$, and $\gamma$ in these two decay modes. We find the $CP$-violating effect induced by the interference between charmed hadron decay and neutral kaon mixing in the ${\Xi }_c^{+}\to {\Sigma }^{+}{K}_S^0$ decay could reach to be $\mathcal{O}(10^{-3})$, which is several times larger than those in $D$ meson decays and at the same order as the $CP$ asymmetry in $K^0-{\overline{K}}^0$ mixing. In contrast, the same term in the ${\Lambda }_c^{+}\to p{K}_S^0$ mode are one order of magnitude smaller. Thus, the ${\Xi }_c^{+}\to {\Sigma }^{+}{K}_S^0$ decay is a promising mode for observing $CP$ asymmetry in the charmed hadron sector and verifying the $CP$-violating effect induced by the interference between charm decay and neutral kaon mixing.

   hep-ph0 citations
10. 10*

    Electron and Photon Structure Functions at Two Loops

    Marvin Schnubel🇺🇸 · Robert Szafron🇺🇸

    We present a fully analytic computation of the complete electron and photon structure functions, or QED lepton parton distribution functions (PDFs) up to two-loop order. Our computation is performed using modern techniques of reduction to Master Integrals and solving them with the differential equation method. We obtain explicit expressions for the electron-in-electron, positron-in-electron, photon-in-electron, electron-in-photon, and photon-in-photon distributions at next-to-next-to-leading order (NNLO). Cross-checks against one-loop results, existing two-loop calculations, and a recent soft-collinear effective theory (SCET) analysis of the electron structure functions are presented.

    hep-phJHEP(2025)·9 citations
11. 11*

    Probing Light Primordial Black Holes through Non-cold Dark Matter

    Yu-Ming Chen🇨🇦

    We study the matter power spectrum constraint on primordial black holes (PBH) by the dark matter (DM) emitted through Hawking radiation. We particularly focus on the scenario where PBH, with mass ranges between 1g and $10^9$g, evaporates before big-bang nucleosynthesis (BBN). Addition to that, we consider the case where PBH abundance is scarce and there is no early PBH domination taking place. On the DM side, we assume a fraction of the population is produced from PBH evaporation, while the remaining part is the regular cold dark matters (CDMs) which is produced by some genesis processes that decouples later on. Therefore, in the rest of the cosmological history, DM interacts solely through gravity. Under this condition, there is no thermal equilibrium ever established between DM and SM plasma. An important feature in our analysis is that, for the light PBH we consider, its temperature is much larger than the mass of DM which is consequently produced ultra-relativistically and require a protracted time to become matter-like. In this context, even though PBH evaporates in the very early Universe, PBH-produced DM could still be energetic and smooth out the small scale structure at much later time. By the precision measurement on the matter power spectrum from cosmic surveys, we are able to set joint constraint on light PBHs and the non-cold DMs it produced.

    hep-phastro-ph.COPRD(2026)·2 citations
12. 12*

    Reionization optical depth and CMB-BAO tension in punctuated inflation

    Zhiqi Huang🇨🇳

    Within the standard six-parameter Lambda cold dark matter ($\Lambda$CDM) model, a $2$-$3\sigma$ tension persists between baryon acoustic oscillation (BAO) measurements from the Dark Energy Spectroscopic Instrument (DESI) and observations of the cosmic microwave background (CMB). Although this tension has often been interpreted as evidence for dynamical dark energy or a sum of neutrino masses below the established minimum, recent studies suggest it may instead originate from an underestimation of the reionization optical depth, particularly when inferred from large-scale CMB polarization. Jhaveri et al. propose that a suppression of large-scale primordial curvature power could partially cancel the contribution of $\tau$ to the CMB low-$\ell$ polarization power spectrum, leading to a biased low $\tau$ measurement in standard analyses. In this work, we investigate whether punctuated inflation - which generates a suppression of primordial power on large scales through a transient fast-roll phase - can raise the inferred $\tau$ value and thereby reconcile the consistency between CMB and BAO. For simple models with step-like features in the inflaton potential, we find that the constraint on $\tau$ and the CMB-BAO tension remain nearly identical to those in the standard six-parameter $\Lambda$CDM model. We provide a physical explanation for this negative result.

    ↳ astro-ph.COgr-qchep-phhep-thMNRAS(2025)·12 citations
13. 13*

    Determination of CKM matrix element and axial vector form factors from weak decays of quantum-entangled strange baryons

    BESIII Collaboration: M. Ablikim · M. N. Achasov · P. Adlarson · X. C. Ai · R. Aliberti · A. Amoroso · Q. An · Y. Bai · O. Bakina · Y. Ban · H.-R. Bao · V. Batozskaya and 717 other authors

    The electromagnetic structure of the nucleon can be determined from the scattering of electrons off a nucleon target. However, to study its axial structure, neutrino beams are required. The results from these experiments should be extrapolated to zero energy-momentum transfers to access the static properties of the nucleon. For baryons with strange quarks, hyperons, the static limit can instead be approached in semi-leptonic decays, which give direct access to the weak magnetism and axial-vector coupling strengths that are inaccessible in electromagnetic interactions. The axial-vector coupling as while weak magnetism coupling and the overall normalization, given by form factor $f_1$, are being determined with increased precision from the theory of strong interactions using a first principles formulation on the space--time lattice. Furthermore, the probability of the semi-leptonic hyperon decay is approximately proportional to $|V_{us}{|}^2\cdot (f_1^2+3g_1^2)$, where $V_{us}$ is the CKM matrix element responsible for the transition between an $s$ and a $u$ quark. Current determinations of $|V_{us}|$ come from kaon decays, but the results are not consistent and could indicate a deviation from CKM matrix unitarity, a tell-tale sign of physics beyond the Standard Model (SM) of elementary particles. Here we determine the absolute branching fraction and weak coupling strengths for $\Lambda \to p{e}^{-}{\bar{\nu }}_e$, and $\bar{\Lambda }\to \bar{p}{e}^{+}{\nu }_e$. These observables combined with form factors determined from first-principle lattice QCD calculations allow for the extraction of the $|V_{us}|$ value. We demonstrate how $|V_{us}|$ can be extracted with increasing sensitivity using polarized hyperons from entangled, baryon-antibaryon pairs, thus enabling a complementary road to that of meson decays. In addition, the presented experimental method can be used for other semileptonic decays of baryons.

    ↳ hep-exhep-ph7 citations
14. 14*

    Reconstruction of the depth of the shower maximum of air showers with the SD-750 surface detector of the Pierre Auger Observatory using neural networks

    Steffen Hahn (for the Pierre Auger Collaboration)

    The origin of ultra-high-energy cosmic rays (UHECRs) is one of the intriguing mysteries in astroparticle physics. In order to identify their sources, we need precise knowledge of the mass composition of UHECRs. The direct detection of UHECRs is not feasible at energies above 0.1 PeV, necessitating the use of mass-sensitive observables of extended air showers induced by UHECRs interacting with the atmosphere. One way to achieve high statistics for these mass-sensitive observables is to use ground-based detector arrays, such as the Surface Detector (SD) of the Pierre Auger Observatory. The SD consists of three sub-arrays of independent detector stations arranged in triangular grids with different spacings. Recently, it has been shown that neural networks (NNs) can extract mass-sensitive observables from data taken by the SD-1500, the largest sub-detector of the SD. In this contribution, we demonstrate the feasibility of using NNs to reconstruct a high-level shower observable, the depth of the shower maximum, from data simulated for and observed by the SD-750, the second-largest detector array nested within the SD-1500. A simulation study shows that the SD-750 NN exhibits behavior similar to that of an SD-1500 NN and outperforms the latter in the energy range [1, 10) EeV. Moreover, we show that, after performing a correction and calibration procedure, the predictions of the SD-750 NN are consistent with the measurement of the depth of the shower maximum obtained by the Fluorescence Detector of the Pierre Auger Observatory.

    ↳ astro-ph.IMastro-ph.HEhep-phPoS(2025)·0 citations
15. 15*

    The Internal Structure of the Deconstructed Dirac Monopole

    Kazuyuki Furuuchi🇮🇳

    I study the internal structure of the Dirac magnetic monopole in a deconstructed $U(1)$ gauge theory. The deconstructed $U(1)$ gauge theory has a product $U(1{)}^N$ gauge group, which breaks down to the diagonal $U(1{)}_{\mathrm{diag}}$ gauge group. A linear superposition of the Dirac monopoles each from each $U(1)$ gauge group placed on top of each other in the 3D space constitutes a Dirac monopole with a unit magnetic charge under the unbroken $U(1{)}_{\mathrm{diag}}$ gauge group. However, the Dirac monopole in each $U(1)$ gauge group has a fractional magnetic charge of the unbroken $U(1{)}_{\mathrm{diag}}$ gauge group with the same sign, which makes these ``constituent'' Dirac monopoles repel each other. Therefore, for the ``composite'' Dirac monopole of the $U(1{)}_{\mathrm{diag}}$ gauge group to be stable, there must be attractive forces that counter the repulsive magnetic Coulomb forces. I argue that such attractive forces are provided by the Nielsen-Olesen type magnetic flux tubes of unbroken gauge groups. This internal structure of the composite Dirac monopole of $U(1{)}_{\mathrm{diag}}$ gauge group resembles the composite magnetic monopole found in the model constructed by Saraswat arXiv:1608.06951. I estimate the size of the Dirac monopole in $U(1{)}_{\mathrm{diag}}$ gauge group from the balance between the magnetic Coulomb forces and the forces from the tension of the magnetic flux tubes. Implications of the results for the Weak Gravity Conjecture are briefly discussed.

    ↳ hep-thhep-ph1 citation
16. 16*

    Fixed points of classical gravity coupled with a Standard-Model-like theory

    Latham Boyle🇬🇧 · Neil Turok🇬🇧 · Vatsalya Vaibhav🇬🇧

    Coupling quantum field theory (QFT) \!-\! even free QFT \!-\! to gravity leads to well-known problems. In particular, the stress tensor $T_{\mu \nu }$ (gravity's source) and its correlators typically diverge in the UV, creating a conflict between the wildly inhomogeneous spacetime we expect quantum mechanically and the weakly-curved, macroscopic spacetime we observe. Are there QFTs for which these divergences cancel? Here, for simplicity, we consider free quantum fields on a classical curved background. The aforementioned divergences are related to the running of the gravitational couplings. We calculate the corresponding beta functions, identifying a special class of QFTs with UV fixed points at which $⟨T_{\mu \nu }⟩$ and all its correlators $⟨T\dots T⟩$ are UV finite. An intriguing example is a theory like the Standard Model (including right-handed neutrinos) with $12$ gauge fields, $3$ generations of $16$ Weyl fermions and $36$ four-derivative (Fradkin-Tseytlin) scalars. In the infrared, this theory has a positive Newton's constant $G$ and an arbitrarily small cosmological constant $\Lambda$.

    ↳ hep-thgr-qchep-ph3 citations
17. 17*

    Toward precise $\xi$ gauge fixing for the lattice QCD

    Li-Jun Zhou🇨🇳 · Dian-Jun Zhao🇨🇳 · Wei-jie Fu🇨🇳 · Chun-Jiang Shi🇨🇳 · Ji-Hao Wang🇨🇳 · Yi-Bo Yang🇨🇳

    Lattice QCD provides a first-principles framework for solving Quantum Chromodynamics (QCD). However, its application to off-shell partons has been largely restricted to the Landau gauge, as achieving high-precision $\xi$-gauge fixing on the lattice poses significant challenges. Motivated by a universal power-law dependence of off-shell parton matrix elements on gauge-fixing precision in the Landau gauge, we propose an empirical precision extrapolation method to approximate high-precision $\xi$-gauge fixing. By properly defining the bare gauge coupling and then the effective $\xi$, we validate our $\xi$-gauge fixing procedure by successfully reproducing the $\xi$-dependent RI/MOM renormalization constants for local quark bilinear operators at 0.3\% level, up to $\xi \sim 1$.

    ↳ hep-lathep-phPRD(2026)·0 citations
18. 18*

    Axion-Photon Conversion in FLRW with Primordial Magnetic Fields: Explaining the Radio Excess

    Setabuddin🇮🇳 · Md Riajul Haque🇮🇳 · Rajesh Karmakar🇨🇳 · Supratik Pal🇮🇳

    We explore the possibility of axion-photon conversion as a common origin of two low-frequency anomalies: the isotropic radio excess (ARCADE2) and the deep global 21-cm absorption trough (EDGES). From the axion-photon action in an FLRW background with primordial magnetic fields (PMFs), we derive the scale-dependent conversion probability including plasma effects. Resonant conversion, arising when the axion mass matches the plasma-induced photon mass, produces soft photons in the MHz-GHz range. By modeling stochastic PMFs with amplitude $B_0$ and spectral index $n_{\mathrm{B}}$, we show that axion-like particles with mass $\sim 10^{-14}$-$10^{-12}\mathrm{eV}$ and nanogauss-level nearly scale invariant PMFs can explain both ARCADE2 and EDGES. Heating from PMF dissipation via ambipolar diffusion and turbulent decay reduces the 21-cm trough, shifting the viable parameter space. Our results stem from a consistent theoretical framework developed from first principles and a combined analysis of the radio excess and global 21-cm signal, while remaining consistent with CMB bounds on PMFs and $\Delta N_{\mathrm{eff}}$. We conclude that global 21-cm observations may offer potential sensitivity to axions, primordial magnetism, and dark-sector physics.

    ↳ astro-ph.COhep-ph3 citations
19. 19*

    Constraints on Ultra-heavy DM from TeV-PeV gamma-ray diffuse measurements

    Manuel Rocamora🇦🇹 · Pedro De La Torre Luque🇪🇸 · Miguel A. Sánchez-Conde🇪🇸

    Recent experiments have measured the Galactic $\gamma$-ray diffuse emission up to PeV energies, opening a window to study acceleration of Galactic cosmic rays and their propagation up to the cosmic-ray knee. Furthermore, these observations provide a powerful tool to set strong constraints into very-heavy dark matter particles, with masses in the TeV-PeV range. In this paper, we explore the potential of the newest observations of diffuse emissions at the Galactic plane from HAWC and LHAASO to probe this kind of dark matter over a wide mass range. Here, we model secondary emissions (inverse-Compton) from the electrons and positrons produced in the annihilation/decay of dark matter, on top of their prompt $\gamma$-ray emission, including the effects of absorption of high-energy photons via pair production. Furthermore, we show that including the astrophysical backgrounds (namely diffuse emission from cosmic-ray collisions or emission from unresolved sources) can significantly improve these limits. We find that the new measurements provided, specially by LHAASO with the combination of the WCDA and KM2A detectors, allow us to set strong constraints in decaying dark matter, being competitive and even improving the strongest constraints at the moment. We also highlight that these regions lead to constraints that are less affected by uncertainties from the dark matter distribution and discuss how CTA north and SWGO will be able to improve limits in this mass range.

    ↳ astro-ph.HEastro-ph.COhep-phPhys.Dark Univ.(2026)·4 citations
20. 20*

    Ultralight Boson Ionization from Comparable-Mass Binaries

    Yuhao Guo🇨🇳 · Zhen Zhong🇵🇹 · Yifan Chen🇩🇰 · Vitor Cardoso🇩🇰 · Taishi Ikeda🇩🇰 · Lihang Zhou🇺🇸

    Detection of gravitational waves enables probes of environmental effects around compact binaries. Ultralight bosons, well motivated in particle physics and capable of forming core-like dark matter structures, induce environmental dynamics that differ qualitatively from those produced by stars or particle dark matter. For comparable-mass binaries, such bosons can form gravitationally bound states analogous to molecules once the binary separation falls below the characteristic wavelength of the bound states, with an inner region co-moving with the binary. We combine numerical simulations and a semi-analytic framework to characterize the structure and ionization of these gravitational molecules. We determine the extent of the co-moving region and compute the ionization flux driven by orbital motion over a range of eccentricities. Using these results, we estimate the backreaction on the binary orbital evolution and identify a new environmental effect: eccentricity-induced ionization of the co-moving component leads to efficient circularization. We further show that this molecular phase can be astrophysically viable and significantly modify the stochastic gravitational wave background from supermassive black hole binaries.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-phJCAP(2026)·17 citations
21. 21*

    Cosmic $\tau$ensions Indirectly Correlate with Reionization Optical Depth

    Itamar J. Allali🇺🇸 · Lingfeng Li🇺🇸 · Praniti Singh🇺🇸 · JiJi Fan🇺🇸

    The reionization optical depth ${\tau }_{\mathrm{reio}}$ has interesting connections to existing cosmological anomalies. As first studied in the context of the Hubble tension in our previous paper, a larger ${\tau }_{\mathrm{reio}}$, which could be achieved by removing the Planck low-$\ell$ polarization data, could boost $H_0$ slightly, resulting in a mild reduction of the tension between the early- and late-universe determinations of $H_0$. It has been shown later that a larger ${\tau }_{\mathrm{reio}}$ could also relieve other anomalies including: the tension between BAO and CMB data, the neutrino mass tension, and the latest DESI plus supernovae data's tension with the standard cosmological constant scenario. In this paper, we systematically analyze the correlations between ${\tau }_{\mathrm{reio}}$ and relevant cosmological parameters in the existing cosmic observation anomalies. In addition to Pearson correlation coefficients extracted directly from the covariance matrix, we also study partial correlation coefficients which measure intrinsic relationships between pairs of parameters removing the influence of other parameters. We show that ${\tau }_{\mathrm{reio}}$ has weak intrinsic correlations with the parameters responsible for the tensions and anomalies discussed. The large direct Pearson correlations that allow larger ${\tau }_{\mathrm{reio}}$ inferences to alleviate the cosmological tensions each arise from complicated networks through multiple parameters. As a result, the relationships between ${\tau }_{\mathrm{reio}}$ and each anomaly are not independent of each other. We also employ our method of computing correlations to clarify the impact of large scale polarization data, and comment also on the effects of CMB observations from ACT and SPT.

    ↳ astro-ph.COhep-phPRD(2026)·17 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.