Mon·Sep 9, 2024Monday·September 9, 2024

1. 01*

   Leptogenesis in SO(10) with Minimal Yukawa sector

   K.S. Babu🇺🇸 · Pasquale Di Bari🇬🇧 · Chee Sheng Fong🇧🇷 · Shaikh Saad🇨🇭

   In prior studies, a very minimal Yukawa sector within the $SO(10)$ Grand Unified Theory framework has been identified, comprising of Higgs fields belonging to a real $10_H$, a real $120_H$, and a ${\overline{126}}_H$ dimensional representations. In this work, within this minimal framework, we have obtained fits to fermion masses and mixings while successfully reproducing the cosmological baryon asymmetry via leptogenesis.The right-handed neutrino ($N_i$) mass spectrum obtained from the fit is strongly hierarchical, suggesting that $B-L$ asymmetry is dominantly produced from $N_2$ dynamics while $N_1$ is responsible for erasing the excess asymmetry. With this rather constrained Yukawa sector, fits are obtained both for normal and inverted ordered neutrino mass spectra, consistent with leptonic CP-violating phase ${\delta }_{\mathrm{CP}}$ indicated by global fits of neutrino oscillation data, while also satisfying the current limits from neutrinoless double beta decay experiments. In particular, the the leptonic CP-violating phase has a preference to be in the range ${\delta }_{\mathrm{CP}}\simeq (230-300{)}^{\circ }$. We also show the consistency of the framework with gauge coupling unification and proton lifetime limits.

   hep-phJHEP(2024)·13 citations
2. 02*

   Factors influencing quantum evaporation of helium from polar semiconductors from first principles

   Lakshay Dheer🇺🇸 · Liang Z. Tan🇺🇸 · S. A. Lyon🇺🇸 · Thomas Schenkel🇺🇸 · Sinéad M. Griffin🇺🇸

   While there is much indirect evidence for the existence of dark matter (DM), to date it has evaded detection. Current efforts focus on DM masses over $\sim$GeV -- to push the sensitivity of DM searches to lower masses, new DM targets and detection schemes are needed. In this work, we focus on the latter - a novel detection scheme recently proposed to detect ~10-100 meV phonons in polar target materials. Previous work showed that well-motivated models of DM can interact with polar semiconductors to produce an athermal population of phonons. This new sensing scheme proposes that these phonons then facilitate quantum evaporation of ${}^3$He from a van der Waals film deposited on the target material. However, a fundamental understanding of the underlying process is still unclear, with several uncertainties related to the precise rate of evaporation and how it can be controlled. In this work, we use \textit{ab initio} density functional theory (DFT) calculations to compare the adsorption energies of helium atoms on a polar target material, sodium iodide (NaI), to understand the underlying evaporation physics. We explore the role of surface termination, monolayer coverage and elemental species on the rate of He evaporation from the target material. Using this, we discuss the optimal target features for He-evaporation experiments and their range of tunability through chemical and physical modifications such as applied field and surface termination.

   hep-phcond-mat.mes-hallcond-mat.mtrl-sciphysics.ins-detPRD(2024)·0 citations
3. 03*

   Lepton-flavor changing decays and non-unitarity in the inverse seesaw mechanism

   Adrián González-Quiterio🇲🇽 · Héctor Novales-Sánchez🇲🇽

   The pursuit for the genuine fundamental description, governing nature at some high-energy scale, must invariably consider the yet-unknown mechanism behind the generation of neutrino mass. Lepton-flavor violating decays $l_{\alpha }\to l_{\beta }\gamma$, allowed in the presence of neutrino mass and mixing, provide a mean to look for physics beyond the Standard Model. In the present work we consider the inverse seesaw mechanism and then revisit the calculation of its contributions to the branching ratios of the aforementioned decay processes. Our analytic results are consistent, as they are gauge invariant, gauge independent, ultraviolet finite, and of decoupling nature. Among the decays $l_{\alpha }\to l_{\beta }\gamma$, we find $\mu \to \gamma e$ to be the most promising, in the light of current bounds by the MEG Collaboration. Deviations from unitarity in the mixing of light neutrinos are related to the branching ratios $\mathrm{Br}(l_{\alpha }\to \gamma l_{\beta })$ in a simple manner, which we address, then finding that the constraints on non-unitarity effects from MEG data will be improved by the upcoming MEG II update by a factor $\sim \frac{1}{3}$.

   hep-phInt.J.Mod.Phys.A(2025)·2 citations
4. 04*

   Parton Distributions of Gluons in Different Representations

   J.P. Ma🇨🇳 · G.P. Zhang🇨🇳

   It has been questioned if gluon distributions defined in different representations of $SU(N)$ are the same. The question has arisen in the connection to the recently proposed resolution of the so-called axial gauge puzzle. We give a proof that gluon distributions defined in the fundamental- and adjoint representation, where gauge links consist of those which are all future-pointing or all past-pointing, are same. These gauge links are needed to make the distributions gauge invariant. When these links consist of not only future-pointing gauge links but also past-pointing ones, then the puzzle appears. We examine the puzzle for distributions at one-loop in the cases with gauge links along time-like-, space-like- and light-cone direction.

   hep-phPLB(2025)·0 citations
5. 05*

   Interstellar medium gas heating by primordial black holes and dark matter particles

   Amane Takeshita🇯🇵 · Teruyuki Kitabayashi🇯🇵

   The Leo T dwarf galaxy has been utilized to investigate the heating of interstellar medium gas by both primordial black holes (PBHs) and dark matter (DM) particles. Previous studies have typically assumed that either PBHs or DM particles are responsible for heating the interstellar medium gas. In contrast, this study considers the simultaneous contribution of both PBHs and DM particles to the heating process. If both PBHs and dark photons heat the gas in Leo T, a stringent constraint on the PBH fraction, $f_{\mathrm{PBH}}={\rho }_{\mathrm{PBH}}/{\rho }_{\mathrm{DM}}$ is obtained for $4\lesssim M_{\mathrm{PBH}}/M_{\odot }\lesssim 10^2$, where ${\rho }_{\mathrm{PBH}}$, ${\rho }_{\mathrm{DM}}$, represent the energy densities of PBHs and DM, respectively, and $M_{\mathrm{PBH}}$, and $M_{\odot }$ denote the masses of PBHs and Sun, respectively. Conversely, if both PBHs and millicharged particles heat the gas, it becomes challenging to impose a more significant constraint on the PBH fraction than previously achieved, due to the very small allowed values of charge parameters within the model.

   hep-phastro-ph.COInt.J.Mod.Phys.A(2025)·4 citations
6. 06*

   Direct quarkonium production in DIS from a joint CGC and NRQCD framework

   Vincent Cheung🇺🇸 · Zhong-Bo Kang🇺🇸 · Farid Salazar🇺🇸 · Ramona Vogt🇺🇸

   We compute the differential cross section for direct quarkonium production in high-energy electron-nucleus collisions at small $x$. Our computation is performed within the nonrelativistic QCD factorization formalism that separates the calculation into short distance coefficients and long distance matrix elements that depend on the color and spin of the state. We obtain the short distance coefficients of the production of the heavy quark pair within the framework of the Color Glass Condensate effective field theory, which resums coherent multiple interactions of the heavy quark pair with the nucleus to all orders. Our results are expressed as the convolution of perturbatively calculable perturbative functions with multi-point light-like Wilson line correlators. In the correlation limit, we establish the correspondence between our CGC formulation with calculations employing the transverse momentum dependent (TMD) framework. We extend this correspondence by resumming kinematic power corrections within the improved TMD framework, which interpolates between the TMD formalism and $k_{\perp }$ factorization formalism. We present a detailed numerical analysis, focusing on $J/\psi$ production in the kinematics accessible at the future Electron-Ion Collider, highlighting the importance of genuine higher-order saturation contributions when the electron collides with a large nucleus.

   hep-phnucl-thPRD(2024)·13 citations
7. 07*

   Low scale leptogenesis under neutrino $\mu$-$\tau$ reflection symmetry

   Yan Shao🇨🇳 · Zhen-hua Zhao🇨🇳

   In the literature, the neutrino $\mu$-$\tau$ reflection symmetry (which has the interesting predictions ${\theta }_{23}^{}=\pi /4$ and $\delta =\pm \pi /2$ for the atmospherical neutrino mixing angle and Dirac CP phase) is an attractive and widely studied candidate for the flavor symmetries in the neutrino sector. But it is known that, when the seesaw model is furnished with this symmetry, the leptogenesis mechanism (which provides an elegant explanation for the baryon-antibaryon asymmetry of the Universe) can only work in the two-flavor regime (which only holds for the right-handed neutrino masses in the range $10^9-10^{12}$ GeV). This prohibits us to have a low scale seesaw model (which has the potential to be directly accessed by running or upcoming collider experiments) that can have the $\mu$-$\tau$ reflection symmetry and successful leptogenesis simultaneously. In this paper, for the first time, we demonstrate that the successful leptogenesis may also be achieved in low scale seesaw models furnished with the $\mu$-$\tau$ reflection symmetry, by means of the flavor non-universality of the conversion efficiencies from the flavored lepton asymmetries to the baryon asymmetry via the sphaleron process. We perform the study in both the resonant leptogenesis regime and the leptogenesis via oscillations (ARS leptogenesis) regime.

   hep-phPRD(2025)·4 citations
8. 08*

   Kaon GTMDs in the Dyson-Schwinger equations using contact interaction

   Jin-Li Zhang🇨🇳

   An array of the kaon twist-two, three, four generalised transverse momentum dependent parton distributions (GTMDs) has been investigated within the framework of covariant and confining Dyson-Schwinger equations using contact interaction. GTMDs are of great significance as they encompass information regarding both the generalised parton distributions (GPDs) and the transverse momentum dependent parton distributions (TMDs), thus being considered as the parent distribution. From GTMDs, we can derive the twist-two, three, four GPDs and TMDs. GPDs are obtained through the integration of ${\mathbf{k}}_{\perp }$ from GTMDs, with a focus on the twist-two GPDs. The first Mellin moments of GPDs yield the form factors of local currents. The second Mellin moments of vector GPDs are related to gravitational form factors. The Wigner distribution can be obtained from a Fourier transform in the transverse space of the GTMDs at skewedness parameter $\xi =0$. The Wigner distributions of an unpolarized, longitudinally polarized, and transversely polarized quark inside the kaon have been calculated. The spin-orbit correlations between a hadron and a quark can be explained based on the phase-space average of Wigner distributions. We investigate the correlation between the longitudinal spin and orbital angular momentum of valence quarks within the pion and kaon. Our findings reveal that $C_z^{u,K}=-0.336$, $C_z^{s,K}=0.242$, and $C_z^{u,\pi }=-0.374$. The parton distribution function in impact parameter space can be derived from the Wigner distribution. The study focuses on the light-front transverse-spin distributions ${\rho }_u^1\left({\mathbf{b}}_{\perp },{\mathbf{s}}_{\perp }\right)$ and ${\rho }_u^2\left({\mathbf{b}}_{\perp },{\mathbf{s}}_{\perp }\right)$, which exhibit distortions, and we calculate their average shift.

   hep-phEPJC(2026)·6 citations
9. 09*

   A diffusion Monte Carlo calculation of fully heavy pentaquarks

   M.C. Gordillo🇪🇸 · J. Segovia🇪🇸 · J.M. Alcaraz-Pelegrina🇪🇸

   Using a diffusion Monte Carlo algorithm, we calculated the spectra of all possible $S$-wave fully heavy pentaquarks within the framework of the quark model. Our aim was to compare the masses of different spin-color configurations corresponding to the same spatial wavefunction for each quark composition. In particular, we computed the masses of the configuration with the maximum number of undistinguishable quarks and those of all the possible baryon+meson splittings compatible with the total number of $b$'s and $c$'s for a given pentaquark. What we found was that, in all cases, compact baryon+meson configurations had lower masses than their more symmetric counterparts. Moreover, those "molecular" associations were unstable (with larger masses) that their infinitely separated non-interacting pieces except int the case of $(ccb)(c\bar{b})$ and $(bbc)(b\bar{c})$ pentaquarks. In any case, even for unstable arrangements, the excess masses are so small ($\sim$20-60 MeV) as to make those compact molecular structures serious candidates to be experimentally detected.

   hep-phPRD(2024)·13 citations
10. 10*

    CP asymmetries of $t\to c\gamma$ and $t\to cg$ decays in the aligned two-Higgs-doublet model

    Fang-Min Cai🇨🇳 · Rui-Lin Fan🇨🇳 · Xin-Qiang Li🇨🇳 · Ya-Dong Yang🇨🇳

    We study the CP asymmetries of the rare top-quark decays $t\to c\gamma$ and $t\to cg$ in the aligned two-Higgs-doublet model (A2HDM), which is generically characterized by new sources of CP violation beyond the Standard Model (SM). Specifically, the branching ratios and CP asymmetries of these rare top-quark decays are explicitly formulated, with an emphasis on the origins of weak and strong phases in the A2HDM. Taking into account the most relevant constraints on this model, we evaluate the variations of these observables with respect to the model parameters. It is found that the branching ratios of $t\to c\gamma$ and $t\to cg$ decays can maximally reach up to $1.47\times 10^{-10}$ and $4.86\times 10^{-9}$ respectively, which are about four and three orders of magnitude higher than the corresponding SM predictions. While the branching ratios are almost independent of the relative phase $\phi$ between the two alignment parameters ${\varsigma }_u$ and ${\varsigma }_d$ within the allowed parameter space, the CP asymmetries are found to be very sensitive to $\phi$. When the two alignment parameters are complex with a non-zero $\phi$ varied within the range $[50^{\circ },150^{\circ }]$, the magnitudes of the CP asymmetries can be significantly enhanced relative to both the SM and the real case. In particular, the maximum absolute values of the CP asymmetries can even reach up to $\mathcal{O}(1)$ for these two decay modes, in the range $\phi \in [70^{\circ },100^{\circ }]$. These interesting observations could be utilized to discriminate the SM and the different scenarios of the A2HDM.

    hep-phEPJC(2025)·4 citations
11. 11*

    Radiative Origin of Fermion Mass Hierarchy in Left-Right Symmetric Theory

    Sudip Jana🇩🇪 · Sophie Klett🇩🇪 · Manfred Lindner🇩🇪 · Rabindra N. Mohapatra🇺🇸

    Despite the remarkable success of the Standard Model, the hierarchy and patterns of fermion masses and mixings remain a profound mystery. To address this, we propose a model employing the rank mechanism, where the originally massless quarks and leptons sequentially get masses. The third-generation masses originate from the seesaw mechanism at the tree level, while those of the second and first generations emerge from one-loop and two-loop radiative corrections, respectively, with a progressive increase in the rank of the mass matrix. This approach does not require new discrete or global symmetries. Unlike other theories of this type that require the introduction of additional scalars, we employ the double seesaw mechanism within a left-right symmetric framework, which allows us to realize this scenario solely through gauge interactions.

    hep-phJHEP(2025)·13 citations
12. 12*

    Sensitivity of jet quenching to the initial state in heavy-ion collisions

    Souvik Priyam Adhya🇵🇱 · Konrad Tywoniuk🇳🇴

    In heavy-ion collisions, nuclear matter is subjected to extreme conditions in a highly dynamical, rapidly evolving environment. This poses a tremendous challenge for calculating jet quenching observables. Current approaches rely on analytical results for static cases, introducing theoretical uncertainties and biases in our understanding of the pre-equilibrated medium. To address this issue, we employ resummation schemes to derive analytical rates for radiative energy loss in generic, evolving backgrounds. We investigate regimes where rare scattering and multiple scattering with the dynamical medium occurs, and extract relevant scales governing the in-medium emission rate of soft gluons. Our analysis indicates that strong jet quenching is only possible when the equilibration time of the medium is longer than its mean free path, highlighting the importance of medium modifications of jets in the earliest stages of heavy-ion collisions. We also demonstrate analytically that a medium evolution, which initially has a small coupling to jets, typically leads to a stronger jet azimuthal asymmetry at the same jet suppression factor.

    hep-phnucl-th14 citations
13. 13*

    Relativistic BEC extracted from a complex FRG flow equation

    Fumio Terazaki🇯🇵 · Kazuya Mameda🇯🇵 · Katsuhiko Suzuki🇯🇵

    Based on the functional renormalization group (FRG) under the local potential approximation, we analyze the Bose-Einstein condensation (BEC) in the relativistic complex scalar theory. This framework leads to a complex flow equation of the effective potential, even with the well-known Litim regulator. In order to evaluate the condensate from such a complex effective potential, we impose a condition between chemical potential and mass, analogously to those in the free theory or the mean field theory. We elucidate that for the strongly (weakly) coupled theory, the phase diagrams computed from the FRG are more (less) deviated from that under the mean field approximation. This result implies that quantum fluctuations strongly affect the nonperturbative formation of the BEC.

    hep-phcond-mat.quant-gashep-thPTEP·4 citations
14. 14*

    First constraint on the weak mixing angle using direct detection experiments

    Tarak Nath Maity🇦🇺 · Celine Boehm🇦🇺

    Current ton-scale dark matter direct detection experiments have reached an important milestone with the detection of solar neutrinos. In this paper, we show that these data can be used to determine a critical parameter of the Standard Model in particle physics, across an energy regime that has never been probed before. In particular, we show that the value of the weak mixing angle (${\theta }_W$) which relates the mass of the $W$ and $Z$ bosons can be derived from 1) the recent measurements of coherent neutrino-nucleus scattering by PandaX-4T and XENONnT in the sub-GeV energy range -- a regime which is usually only probed by low energy neutrino experiments -- and from 2) XENONnT electron recoil data through neutrino-electron scattering at energy scale $\simeq 0.1\mathrm{MeV}$, corresponding to a momentum transfer region over an order of magnitude smaller than that explored by atomic parity violation experiments. Now that an indicative measurement of the weak mixing angle exists at these lowest energy frontier, the challenge for the next generation of such experiments will be to provide a more precise measurement in the keV-MeV energy range.

    hep-phastro-ph.SRhep-exPRD(2025)·30 citations
15. 15*

    Mass Reconstruction of Heavy Neutral Leptons from Stopped Mesons

    Gustavo F. S. Alves🇧🇷 · P. S. Bhupal Dev🇺🇸 · Kevin J. Kelly🇺🇸 · Pedro A. N. Machado🇺🇸

    Heavy neutral leptons (HNLs), depending on their mass and mixing, can be efficiently produced in meson decays from the target or absorber in short- to medium-baseline accelerator neutrino experiments, leaving detectable signals through their decays inside the neutrino detectors. We show that the currently running ICARUS experiment at Fermilab can reconstruct the HNL mass and explore new HNL parameter space in the mass range of 70-190 MeV. The mass reconstruction is enabled by two ingredients: (i) simple two-body kinematics of HNL production from stopped kaon decays at the NuMI absorber, followed by HNL decay into a charged-lepton pair and neutrino at the detector, and (ii) high resolution of Liquid Argon Time Projection Chamber (LArTPC) detectors in reconstructing final state particles. Our mass reconstruction method is robust under realistic energy resolution and angular smearing of the charged leptons, and is applicable to any LArTPC detector. We also discuss the synergy between ICARUS and future facilities like DUNE near detector and PIP-II beam dump in probing the HNL parameter space.

    hep-phhep-exPRD(2025)·7 citations
16. 16*

    The Gamow and the Fermi Golden Rules

    Rafael de la Madrid🇺🇸

    By using the fact that the Gamow states in the momentum representation are square integrable, we obtain the differential and the total decay width of a two-body, non-relativistic decay. The resulting Gamow Golden Rule is well suited to describe both energy and angular decay distributions, and it becomes the Fermi Golden Rule when the resonance is long-lived and far from the energy threshold. We also show that the correct density of states and phase space factors arise naturally from the Gamow Golden Rule. The upshot is that the Gamow states and the Golden Rule can be combined into a unified description of quantum resonances.

    ↳ quant-phhep-phNPA(2024)·3 citations
17. 17*

    Response of interferometers to the vacuum of quantum gravity

    Daniel Carney🇺🇸 · Manthos Karydas🇺🇸 · Allic Sivaramakrishnan🇺🇸

    It has recently been suggested that exotic quantum gravity effects could lead to large vacuum fluctuations, potentially observable with realistic detectors. Experiments are currently being built to search for these signals. Here we analyze the minimal model of quantum gravity at low energies -- the usual effective quantum field theory of gravitons -- and show that it unambiguously predicts an unobservably small variation in the measured interferometer length $\Delta L\sim {\ell }_{\mathrm{pl}}\sim 10^{-35}\mathrm{m}$. In particular, there are no divergences signaling a breakdown of this calculation in the low energy regime. Thus, detection of a large, gravitationally-induced length variation would signal a severe breakdown of effective quantum field theory in low energy quantum gravity.

    ↳ hep-thgr-qchep-phPRD(2026)·19 citations
18. 18*

    AxionH0graphy: hunting for ultralight dark matter with cosmographic H${}_0$ signal

    Kfir Blum🇮🇱 · Luca Teodori🇮🇱

    If ultralight boson fields exist, then vacuum misalignment populates them with nonzero relic abundance. For a broad range of particle mass $m$ the field condenses into fuzzy cores in massive galaxies. We use numerical simulations to test this idea, extending previous work (Blum and Teodori 2021) and focusing on ultralight dark matter (ULDM) that makes-up a subdominant fraction of the total dark matter density, consistent with observational constraints. Our simulations mimic galactic halos and explore different initial conditions and levels of sophistication in the modeling of the halo potential. For $m\sim 10^{-25}$ eV ULDM cores act as approximate internal mass sheets in strong gravitational lensing, and could first be detected as an $H_0$ bias in cosmography: a scenario we dub AxionH0graphy. The mass sheet degeneracy is broken by finite core radius and by the dynamical displacement of cores from the halo center of mass, which introduce imaging distortions and restrict the $H_0$ bias limit of AxionH0graphy to $m\lesssim 5\times 10^{-25}$ eV. Cosmological simulations are called for to sharpen the predicted connection between the amplitude of ULDM galactic cores and the ULDM cosmological fraction.

    ↳ astro-ph.COastro-ph.GAhep-phPRD(2025)·7 citations
19. 19*

    Deuteron, triton, helium-3 and hypertriton production in relativistic heavy-ion collisions via stochastic multi-particle reactions

    Martha Ege🇩🇪 · Justin Mohs🇩🇪 · Jan Staudenmaier🇩🇪 · Hannah Elfner🇩🇪

    The production of light nuclei in heavy -ion collisions is an excellent probe for studying the phase diagram of quantum chromodynamics and for the search of a critical end point. In this work we apply a hybrid approach in which we study the light nuclei production in the afterburner stage of central Au+Au collisions at ${\sqrt{s}}_{NN}=7.7$, 14.5 and 19.6 GeV. In this stage, light nuclei are produced dynamically in $4\leftrightarrow 2$ catalysis reactions. A comparison of the dynamic production and a coalescence approach is presented for transverse momentum spectra of deuterons, tritons, ${}^3\mathrm{He}$ nuclei and hypertritons and ratios of light nuclei yields. A good agreement with the experimentally measured yield of nuclei is found and we proceed to further investigate the production mechanisms of light nuclei by calculating the rates of the important channels for the formation and disintegration. We find that the afterburner stage is essential for the description of light nuclei formation in heavy-ion collisions, as light nuclei undergo a large number of interactions.

    ↳ nucl-thhep-phPRC(2025)·10 citations
20. 20*

    The Second-Level Preheating

    Norma Sidik Risdianto🇮🇩 · Apriadi Salim Adam🇮🇩 · Lalu Zamakhsyari🇯🇵

    This paper proposes two levels of preheating for the inflaton that is non-minimally coupled with gravity. The first level, later named by the quadratic regime, corresponds to the matter-dominated era and is responsible for draining the inflaton's energy density. The second level, which we will call the quartic regime, corresponds to the radiation-dominated era and is responsible for the reheating of the universe. We investigate the behavior of non-renormalizable higher dimension operators in both the quadratic and quartic regimes. In the quadratic regime, the preheating is also efficient, even though it is less than the lower dimension. On the other hand, the non-renormalizable higher dimension operators in the quartic regime are extremely inefficient. In our work, we also introduce a simple mechanism controlled by the characteristic momentum $\alpha$ to suppress the particle production during preheating. Additionally, we emphasized the significance of the small momentum of the particles produced during preheating for the abundance of primordial black holes. This result supports the efficient preheating in the quadratic regime. Finally, we evaluate two modes of the reheating temperature, which differ based on the preheating efficiency during the quadratic regime.

    ↳ gr-qcastro-ph.COhep-phJCAP(2025)·1 citation
21. 21*

    Bayesian solution to the inverse problem and its relation to Backus-Gilbert methods

    Luigi Del Debbio🇬🇧 · Alessandro Lupo🇫🇷 · Marco Panero🇮🇹 · Nazario Tantalo🇮🇹

    The problem of obtaining spectral densities from lattice data has been receiving great attention due to its importance in our understanding of scattering processes in Quantum Field Theory, with applications both in the Standard Model and beyond. The problem is notoriously difficult as it amounts to performing an inverse Laplace transform, starting from a finite set of noisy data. Several strategies are now available to tackle this inverse problem. In this work, we discuss how Backus-Gilbert methods, in particular the variation introduced by some of the authors, relate to the solution based on Gaussian Processes. Both methods allow computing spectral densities smearing with a kernel, whose features depend on the detail of the algorithm. We will discuss such kernel, and show how Backus-Gilbert methods can be understood in a Bayesian fashion. As a consequence of this correspondence, we are able to interpret the algorithmic parameters of Backus-Gilbert methods as hyperparameters in the Bayesian language, which can be chosen by maximising a likelihood function. By performing a comparative study on lattice data, we show that, when both frameworks are set to compute the same quantity, the results are generally in agreement. Finally, we adopt a strategy to systematically validate both methodologies against pseudo-data, using covariance matrices measured from lattice simulations. In our setup, we find that the determination of the algorithmic parameters based on a stability analysis provides results that are, on average, more conservative than those based on the maximisation of a likelihood function.

    ↳ hep-lathep-phEPJC(2025)·34 citations
22. 22*

    On the Role of Muons in Binary Neutron Star Mergers: First Simulations

    Henrique Gieg🇩🇪 · Federico Schianchi🇩🇪 · Maximiliano Ujevic🇧🇷 · Tim Dietrich🇩🇪

    In this work we present a set of binary neutron star (BNS) merger simulations including the net muon fraction as an additional degree-of-freedom in the equation of state (EoS) and hydrodynamics evolution using the numerical-relativity code BAM. Neutrino cooling is modeled via a neutrinos leakage scheme, including in-medium corrections to the opacities and emission rates of semi-leptonic charged-current reactions, although within the elastic approximation. We show that, for our particular choice of baseline baryonic EoS, the presence of muons delays the gravitational collapse of the remnant compared to the case where muons are neglected. Furthermore, when muons and muonic weak reactions are considered, no gravitational collapse occurs within our simulation time and muons are confined in the densest portions of the remnant, while the disk is effectively colder, less protonized and de-muonized. Accordingly, ejecta properties are affected, e.g., ejecta masses are systematically smaller for the muonic setups and exhibit a larger fraction of neutron-rich, small velocity material. Overall, our results suggest that the inclusion of muons and muon-flavored neutrino reactions in the context of BNS merger simulations should not be neglected, thus representing an important step towards more realistic modeling of such systems.

    ↳ gr-qcastro-ph.HEhep-phPRD(2025)·23 citations
23. 23*

    Memory burden effect mimics reheating signatures on SGWB from ultra-low mass PBH domination

    Nilanjandev Bhaumik🇨🇳 · Md Riajul Haque🇮🇳 · Rajeev Kumar Jain🇮🇳 · Marek Lewicki🇵🇱

    Ultra-low mass primordial black holes (PBH), briefly dominating the expansion of the universe, would leave detectable imprints in the secondary stochastic gravitational wave background (SGWB). Such a scenario leads to a characteristic doubly peaked spectrum of SGWB and strongly depends on the Hawking evaporation of such light PBHs. However, these observable signatures are significantly altered if the memory burden effect during the evaporation of PBHs is taken into account. We show that for the SGWB induced by PBH density fluctuations, the memory burden effects on the Hawking evaporation of ultra-low mass PBHs can mimic the signal arising due to the non-standard reheating epoch before PBH domination. Finally, we point out that this degeneracy can be broken by the simultaneous detection of the first peak in the SGWB, which is typically induced by the inflationary adiabatic perturbations.

    ↳ astro-ph.COgr-qchep-phhep-thJHEP(2024)·47 citations
24. 24*

    Primordial Black Holes in the Solar System

    Valentin Thoss🇩🇪 · Andreas Burkert🇩🇪

    If primordial black holes (PBHs) of asteroidal mass make up the entire dark matter, they could be detectable through their gravitational influence in the solar system. In this work, we study the perturbations that PBHs induce on the orbits of planets. Detailed numerical simulations of the solar system, embedded in a halo of PBHs, are performed. We find that the gravitational effect of the PBHs is dominated by the closest encounter. Using the Earth-Mars distance as an observational probe, we show that the perturbations are smaller than the current measurement uncertainties and thus PBHs are not directly constrained by solar system ephemerides. We estimate that an improvement in the ranging accuracy by an order of magnitude or the extraction of signals well below the noise level is required to detect the gravitational influence of PBHs in the solar system in the foreseeable future.

    ↳ astro-ph.EPgr-qchep-phApJ(2025)·10 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.