Thu·Sep 5, 2024Thursday·September 5, 2024

1. 01*

   $Z^{\prime }$-mediated dark matter freeze-in at stronger coupling

   Giorgio Arcadi🇮🇹 · David Cabo-Almeida🇮🇹 · Oleg Lebedev🇫🇮

   We study freeze-in production of fermionic dark matter mediated by a $Z^{\prime }$ gauge boson. In particular, we explore the regime of Boltzmann-suppressed production, when the Standard Model (SM) thermal bath temperature never exceeds the dark matter mass. The corresponding gauge coupling is then required to be significant, up to order one. As a result, this class of freeze-in models can be probed by the current and future direct dark matter detection experiments.

   hep-phPLB(2025)·27 citations
2. 02*

   Automated inclusion of QED corrections in Monte Carlo event generators

   Lois Flower🇬🇧

   In this thesis, we present automated, process-independent methods for the calculation of QED real radiative corrections. We review the construction of a parton shower based on Catani-Seymour dipole subtraction, and thus detail the implementation of a QED parton shower. We validate the predictions made by the shower against the YFS soft-photon resummation, and discuss the algorithmic choices made. We then present results for the production of a Higgs boson at the LHC and its decay to leptons, showing that the interleaved QCD+QED parton shower predicts distributions in excellent agreement with the YFS approach. We then study the MC@NLO method for matching a next-to-leading order calculation with a parton shower. Showing that the method preserves its accuracy for the case of QED corrections and of mixed QCD and QED corrections, we present the QCD+QED MC@NLO method. Validating the method against both the YFS resummation and the QED parton shower, we find very good agreement. Finally, we present an extension to the YFS soft-photon resummation, in which we use a one-step parton shower to resum the logarithms associated with charged particle pair production. Throughout this thesis we also discuss the impact of dressed lepton definitions on observables. The methods presented in this thesis are made available in a public Monte Carlo event generator and analysis framework.

   hep-ph0 citations
3. 03*

   Scalar radiation zeros at the LHC

   Christoph Englert🇬🇧 · Andrei Lazanu🇬🇧 · Peter Millington🇬🇧

   We consider a class of singlet scalar extensions of the Standard Model of particle physics in which the scalar couples only to off-shell states. As a result, low-order tree-level processes involving the singlet scalar vanish, providing a unique phenomenology that may allow to evade existing constraints on new singlet scalar fields. We describe search strategies for such states at the Large Hadron Collider and identify the parameter space that can be explored in the future.

   hep-phhep-exJHEP(2024)·2 citations
4. 04*

   Unified Origin of Inflation, Baryon Asymmetry, and Neutrino Mass

   Ajay Kaladharan🇺🇸 · Shaikh Saad🇨🇭

   In this work, we present a unified theoretical framework that simultaneously addresses some of the most intriguing puzzles in particle physics and cosmology, namely the origins of neutrino mass, baryon asymmetry, and cosmic inflation. In our model, inflation is driven by a combination of the Standard Model Higgs, the type II seesaw Higgs responsible for neutrino mass generation, and the unified symmetry-breaking Higgs field. During inflation, non-zero values of the latter field ensure the absence of the monopole problem. The baryon asymmetry is generated through the Affleck-Dine mechanism, facilitated by the non-zero angular motion in the phase of a complex scalar field, which is part of the inflaton. We find that the successful parameter region for generating baryon asymmetry through a renormalizable term in the scalar potential requires a rather heavy type II seesaw triplet, with a mass well beyond the TeV scale. Inflationary observables, in particular, the spectral index is in excellent agree with experimental observation, whereas tensor-to scalar ratio is expected to be probed by the future LiteBIRD and CMB-S4 missions.

   hep-phastro-ph.COPRD(2024)·7 citations
5. 05*

   Sphaleron and gravitational wave with the Higgs-Dilaton potential in the Standard Model Two-Time Physics

   Vo Quoc Phong🇻🇳 · Quach Ai Mi🇻🇳 · Nguyen Xuan Vinh🇻🇳

   By introducing a Higgs-Dilaton potential, the 2T model has a trigger for a first order electroweak phase transition, namely for the mass of Dilaton between $300$ GeV and $550$ GeV. We have also compared the transition strengths in the case with and without daisy loops, the difference being always less than $0.2$. The effective Higgs potential has given a sphaleron energy less than $8.4$ TeV. The timescale of phase transition $(\beta /H^{\ast })$ is larger than $25$ and less than $34$ in all cases that are sufficient to trigger the first order electroweak phase transition. Gravitational wave energy density caused by this transition, may be detected by future detectors, could indirectly confirm Dilaton.

   hep-phNPB(2025)·1 citation
6. 06*

   Two-pole structure of the $h_1(1415)$ axial-vector meson: resolving mass discrepancy

   Samson Clymton🇰🇷 · Hyun-Chul Kim🇰🇷

   We investigate isoscalar axial-vector mesons using a coupled-channel formalism. The kernel amplitudes are constructed from meson-exchange diagrams in the $t$- and $u$-channels, which are derived from effective Lagrangians based on hidden local symmetry. We incorporate six channels: $\pi \rho$, $\eta \omega$, $K{\bar{K}}^{\ast }$, $\eta \varphi$, ${\eta }^{\prime }\omega$, and ${\eta }^{\prime }\varphi$, and solve the off-shell coupled integral equations. We first discuss the dynamical generation of the $h_1(1170)$. The pole diagram for $h_1(1595)$ has a certain effect on the generation of $h_1(1170)$. We observe two poles at $(1387-i6)$ MeV and $(1452-i51)$ MeV, which exhibit a two-pole structure of the $h_1(1415)$ meson. This two-pole structure may resolve the discrepancy in the experimental data on the mass of $h_1(1415)$. The results show that the lower pole couples strongly to the $K{\bar{K}}^{\ast }$ channel, while the higher pole couples predominantly to the $\eta \varphi$ channel. This provides insights into the nature of $h_1$ mesons and explains ossible discrepancies in the mass of $h_1(1415)$.

   hep-phhep-exPRD(2024)·11 citations
7. 07*

   Pressure-Tunable Targets for Light Dark Matter Direct Detection: The Case of Solid Helium

   Omar A. Ashour🇺🇸 · Sinéad M. Griffin🇺🇸

   We propose hydrostatic pressure -- a well-established tool for tuning properties of condensed matter -- as a novel route for optimizing targets for light dark matter direct detection, specifically via phonons. Pressure dramatically affects compressible solids by boosting the speed of sound and phonon frequencies. Focusing on helium -- the most compressible solid -- our ab initio calculations illustrate how high pressure elevates helium from lacking single-phonon reach to rivaling leading candidates. Our work establishes pressure as an unexplored tuning knob for accessing lower dark matter mass regimes.

   hep-phcond-mat.mes-hallcond-mat.mtrl-sciphysics.ins-det7 citations
8. 08*

   Weak decays of $B_s$ to $D_s$ based on the helicity analysis

   Sara Rahmani🇨🇳

   Employing dipole and exponential hadronic transition form factors and helicity analysis combined with the Lattice QCD input, we present a detailed study of the decays $B_s\to D_s^{(\ast )}\ell {\nu }_{\ell }$. $B_s\to D_s+P(V)$, where $P={\pi }^{+},K^{+},D_s^{+}$ and $V={\rho }^{+},K^{\ast +},D_s^{\ast +}$, are also investigated and their branching fractions are examined. At the large recoil point, we calculate $f_{+,0}^{B_s\to D_s}(0)=0.67\pm 0.01$ for both parameterizations. Then we evaluate the branching fractions $BR(B_s\to D_s\ell \nu )$ and $BR(B_s\to D_s\ell \nu )$, which leads to $R(D_s)=0.298\pm 0.123$. The ratios $\frac{\Gamma (B_s^0\to D_s^{-}{\mu }^{+}{\nu }_{\mu })}{\Gamma (B_s^0\to D_s^{\ast -}{\mu }^{+}{\nu }_{\mu })}$ are found to be $0.4415\pm 0.1860$ and $0.4406\pm 0.1854$, which are in good agreement of recent LHCb collaboration measurement. We also calculate the physical observables, $A_{FB}^{\ell },P_L^{\ell },P_T^{\ell },C_F^{\ell },F_L^{\ell }$.

   hep-phPhys.Scripta(2025)·2 citations
9. 09*

   Axion Minicluster Halo Limits from Wide Binary Disruption

   Zihang Wang🇨🇳 · Yu Gao🇨🇳

   Axionic dark matter can form miniclusters and minicluster halos from inhomogenuities in the early Universe. If MCHs are sufficiently massive, their existence can be revealed by small-scale gravitational tidal perturbation to halo-like binary star system in the Galaxy. The observed population of the Milky Way's wide-separation binaries with $a\gtrsim \mathcal{O}(0.1)$ parsec offer a sensitive test to dynamic evaporation from MCHs. Considering data from recent GAIA observations, we derive significant constraints on the MCH fraction of the galactic dark matter halo. For several scenarios including dense MCHs and isolated minicluster models, these limits will apply to axion-like particles in the mass range $m_a\sim 10^{-15}-10^{-12}\mathrm{eV}$ and $m_a\sim 10^{-19}-10^{-16}\mathrm{eV}$, respectively.

   hep-phastro-ph.COPRD(2025)·3 citations
10. 10*

    Twin electroweak bubble nucleation and gravitational wave under the $S_3$ symmetry of two-Higgs-doublet model

    Vo Quoc Phong🇻🇳 · Nguyen Xuan Vinh🇻🇳 · Phan Hong Khiem🇻🇳

    Sphaleron electroweak phase transition (EWPT) is calculated in two phase transition stages, thereby showing that the twin (or double) bubble nucleation structure of the phase transition and gravitational wave is in the investigation area of future detectors. With $v^2=v_1^2+v_2^2$ ($v_1$ and $v_2$ are two vacuum average values (VEV)) and $a=v^2/v_2^2$ which affects the expansion of bubbles during two phase transitions. The more $a$ increases, the more the expansion of two bubbles is at the same time. This ratio does not greatly affect the sphaleron energy but has an impact on gravitational waves. The larger the masses of the charged Higgs particles are, the greater the gravitational wave energy density ($\Omega h^2$) is. When the frequency is in the range $0-1.2$ mHz, $\Omega h^2$ will has a maximum value in the range $10^{-12}-10^{-11}$ for all values of $a$ so this can be detected in the future.

    hep-phInt.J.Mod.Phys.D(2025)·0 citations
11. 11*

    Explaining 95 GeV Anomalies in the 2-Higgs Doublet Model Type-I

    Akshat Khanna🇮🇳 · Stefano Moretti🇬🇧 · Agnivo Sarkar🇮🇳

    We show how the 2-Higgs Doublet Model (2HDM) Type-I can explain some excesses recently seen at the Large Hadron Collider (LHC) in $\gamma \gamma$ and ${\tau }^{+}{\tau }^{-}$ final states in turn matching Large Electron Positron (LEP) data in $b\bar{b}$ signatures, all anomalies residing around 95 GeV. The explanation to such anomalous data is found in the aforementioned scenario when in inverted mass hierarchy, in two configurations: i) when the lightest CP-even Higgs state is alone capable of reproducing the excesses; ii) when a combination of such a state and the CP-odd Higgs boson is able to do so. To test further this scenario, we present some Benchmark Points (BPs) of it amenable to phenomenological investigation.

    hep-phNPB(2026)·18 citations
12. 12*

    Renormalization Group Equations for the Dimension-7 SMEFT Operators

    Di Zhang🇩🇪

    In this talk, a Green's basis and a new physical basis for dimension-seven (dim-7) operators in the Standard Model effective field theory (SMEFT) are proposed. The reduction relations between those two bases are also presented, where some redundant dim-6 operators in the Green's basis are involved if the dim-5 operator exists. Taking advantage of these two bases for dim-7 operators and the associated reduction relations, we work out the complete one-loop renormalization group equations (RGEs) for dim-5 and dim-7 operators up to $\mathcal{O}\left({\Lambda }^{-3}\right)$ in the SMEFT, including not only the mixing among the same dimensional operators but also that among different dimensional ones. These results can be exploited to study full one-loop RG effects on some lepton- or baryon-number-violating processes up to $\mathcal{O}\left({\Lambda }^{-3}\right)$ in the SMEFT, such as neutrino masses, neutrinoless double beta decay, meson and nucleon decays.

    hep-phhep-exPoS(2025)·2 citations
13. 13*

    Theory on CKM and heavy quark decay

    Oliver Witzel🇩🇪

    The combination of precise experimental measurements and theoretical predictions allows to extract Cabibbo-Kobayashi-Maskawa (CKM) matrix elements or constrain flavor changing processes in the standard model. Focusing at theoretical predictions, we review recent highlights from the sector of heavy charm and bottom quark decays. Special emphasis is given to nonperturbative contributions due to the strong force calculated using lattice QCD.

    hep-phhep-latEPJ Web Conf.(2024)·1 citation
14. 14*

    An Extended Closure Relation by LightGBM for Neutrino Radiation Transport in Core-collapse Supernovae

    Shota Takahashi🇯🇵 · Akira Harada🇯🇵 · Shoichi Yamada🇯🇵

    We developed a machine learning model using LightGBM, one of the most popular gradient-boosting decision tree methods these days, to predict the Eddington tensor, or the second-order angular moment, for neutrino radiation transport in core-collapse supernova simulations. We use not only the zeroth and first moments of the neutrino distribution function in momentum space as in ordinary closure relations but also information on the background matter configuration extensively. For training the model, we utilize some post-bounce snapshots from one of our previous Boltzmann radiation-hydrodynamics simulations; the Eddington tensor as well as the zeroth and first angular moments are calculated from the neutrino distribution function obtained in the simulation. LightGBM is light indeed, and its high efficiency in training enables us to feed a large number of features and figure out which features are more important than others. In this paper, we report the results of this feature engineering in addition to those of the training, validation, and generalization of our model. We find that the flux factor and non-local features are among the most relevant features; our LightGBM model can reproduce the Eddington factor better in general than the M1 closure relation, one of the most commonly employed algebraic closure relations at present; the generalization performance is also much improved from our previous model based on the deep neural network.

    hep-phastro-ph.HEApJ(2025)·1 citation
15. 15*

    Muon collider probes of Majorana neutrino dipole moments and masses

    Michele Frigerio🇫🇷 · Natascia Vignaroli🇮🇹

    Majorana neutrinos may have transitional dipole moments, which violate lepton number as well as lepton flavour. We estimate the sensitivity of future colliders to the electron-muon neutrino dipole moment, ${\lambda }_{e\mu }$, by considering same-sign dilepton final states. We find that hadron colliders, even the proposed FCC-hh, are sensitive only to $|{\lambda }_{e\mu }|\gtrsim 10^{-9}{\mu }_B$ (with ${\mu }_B$ the Bohr magneton), a value two-three orders of magnitude larger than current bounds from astrophysics and low-energy neutrino-scattering experiments. In the case of a future muon collider, we show that the sensitivity varies from $|{\lambda }_{e\mu }|\sim 5\cdot 10^{-9}{\mu }_B$ for energy $\sqrt{s}\simeq 3$ TeV, to $\sim 10^{-12}{\mu }_B$ for $\sqrt{s}\simeq 50$ TeV, matching the current laboratory bounds for $\sqrt{s}\simeq 30$ TeV. The singular advantage of the muon collider signal would be a direct, clean identification of lepton number and flavour violation. We also show that a muon collider would improve by orders of magnitude the direct bounds on $m_{e\mu }$ and $m_{\mu \mu }$, two of the entries of the Majorana neutrino mass matrix. These bounds could be as strong as $\sim 50$ keV, still far above the neutrino mass scale.

    hep-phastro-ph.SRhep-exJHEP(2025)·15 citations
16. 16*

    The Interaction of Moving $\mathbf{Q}\bar{\mathbf{Q}}$ and QQq in the Thermal Plasma

    Xuan Liu🇨🇳 · Sheng Lin🇨🇳 · Xun Chen🇨🇳

    The strength of the interaction between heavy quarks is studied for heavy quarkonium ($\mathrm{Q}\bar{\mathrm{Q}}$) and doubly heavy baryons ($\mathrm{QQq}$) at finite temperature and rapidity using the gauge/gravity duality in this paper. We show that this theoretical framework is capable of simultaneously and accurately describing both $\mathrm{Q}\bar{\mathrm{Q}}$ and $\mathrm{QQq}$ by fitting lattice potentials. In this framework, we study their interaction at long distances or low temperature and rapidity through effective string tension, while the interaction at short distances or high temperature and rapidity is studied through effective running coupling. Additionally, we plot their state diagram in the $T-\eta$ plane and systematically calculate their respective screening distances.

    hep-phNPA(2026)·2 citations
17. 17*

    Establishing CP Violation in $b$-Baryon Decays

    Jia-Jie Han🇨🇳 · Ji-Xin Yu🇨🇳 · Ya Li🇨🇳 · Hsiang-nan Li🇹🇼 · Jian-Peng Wang🇨🇳 · Zhen-Jun Xiao🇨🇳 · Fu-Sheng Yu

    It is a long-standing puzzle why the {\it CP} violation (CPV) in the baryon system has not yet been definitively established as in the meson one. We demonstrate that individual partial-wave CPV in the ${\Lambda }_b\to p{\pi }^{-}$ and $p{K}^{-}$ decays can exceed $10\%$, but the destruction between the partial waves (the suppression by the small partial-wave weight) results in a small net direct CPV in the former (the latter) as measured currently. Our finding highlights the different dynamics responsible for CPVs in baryon and meson decays. We propose to probe the CPV observables associated with the angular distributions of the ${\Lambda }_b\to p{a}_1(1260)$, $p{K}_1(1270)$ decay products, which are large enough for being identified experimentally.

    hep-phhep-exPRL(2025)·41 citations
18. 18*

    Muon $g$$-$$2$: blinding for data-driven hadronic vacuum polarization

    Alexander Keshavarzi🇬🇧 · Daisuke Nomura🇯🇵 · Thomas Teubner🇬🇧 · Aidan Wright🇬🇧

    The KNT(W) data-driven determinations of the hadronic vacuum polarization (HVP) are crucial inputs to previous and future Standard Model (SM) predictions of the muon's anomalous magnetic moment, $a_{\mu }$. With the muon $g$$-$$2$'s new physics case uncertain due to disagreeing HVP evaluations, new SM predictions and experimental measurements of $a_{\mu }$ expected soon, and a complete revamp of the KNTW analysis framework underway, this letter motivates and describes a blinding scheme for data-driven HVP determinations that has been implemented for future KNTW analyses.

    hep-phhep-exPRD(2025)·13 citations
19. 19*

    Constraints for twist-two alien operators in QCD

    G. Falcioni🇮🇹 · F. Herzog🇬🇧 · S. Moch🇩🇪 · S. Van Thurenhout🇭🇺

    Parton evolution equations in QCD are controlled by the anomalous dimensions of gauge-invariant twist-two spin-$N$ quark and gluon operators. Under renormalization, these mix with gauge-variant operators of the same quantum numbers, referred to as alien operators. Our work addresses the systematic study of these alien operators at arbitrary spin $N$, using generalized BRST symmetry relations to derive their couplings and Feynman rules at all values of $N$. We observe how the all-$N$ structure of the generalized (anti-)BRST constraints relates the couplings of alien operators with $n+1$ gluons to those with $n$ gluons. Realizing a bootstrap, we present all one-loop results necessary for performing the operator renormalization up to four loops in QCD.

    hep-phhep-thJHEP(2024)·15 citations
20. 20*

    Single Pion Production off Free Nucleons: Analysis of Photon, Electron, Pion and Neutrino Induced Processes

    M. Kabirnezhad🇬🇧

    In this paper, I introduce a unified model for single-pion production across photo-, electro-, and neutrino-nucleon interactions, designed to be valid over a broad kinematic range that is crucial for accelerator-based neutrino experiments. This model includes vector and axial-vector nucleon transition form factors for all excited nucleons or resonances up to 2 GeV, as well as non-resonant backgrounds, within a meson dominance framework that adheres to QCD principles and ensures unitarity. This approach guarantees accurate asymptotic behaviour at high momentum transfer and effectively addresses the transition region. Additionally, the model employs the Conserved Vector Current and Partially Conserved Axial Current relations to provide reliable predictions at very low momentum transfer, tackling challenges encountered by current neutrino experiments. The unified model facilitates a comprehensive analysis by integrating all available data from electron, photon, pion, and neutrino scattering experiments. This integration enables a detailed investigation of nucleon structure within the resonance region and is particularly valuable for probing weak interactions, where neutrino-nucleon data are limited. The combined analysis allows for the simultaneous parameterisation and constraint of the model free parameters, while quantifying associated uncertainties, thus providing a robust and reliable framework for future neutrino measurements.

    hep-ph5 citations
21. 21*

    Electroweak gauge invariant Higgs multiplets

    M. Maniatis🇨🇱

    We investigate the potential of general Higgs multiplets. We establish the domain of general Higgs multiplets within the context of the adjoint representation. The construction of the most general potential for arbitrary multiplets is achieved using the irreducible, totally symmetric representation of tensor products of doublets. Furthermore, we explore symmetry transformations of the Higgs multiplets, with particular emphasis on CP symmetries.

    hep-phJHEP(2024)·0 citations
22. 22*

    Schwinger Effect of Extremal Reissner-Nordström Black Holes

    Puxin Lin🇺🇸 · Gary Shiu🇺🇸

    The Schwinger effect has a variety of physics applications. In the context of black hole physics, it provides a channel for the decay of charged black holes. While the Schwinger rate has been derived for extremal Reissner-Nordström (RN) black hole using the $Ad{S}_2\times S^2$ geometry of the horizon, a full analysis in the whole geometry is lacking, begging the question of whether it is sufficient to ignore contributions away from the horizon. In this paper, we address this problem and obtain the spatial profile of the Schwinger production rate in an asymptotically flat RN black hole spacetime. We find that the Schwinger effect is strongest on the horizon and decays with distance from the horizon, exhibiting a characteristic scale of the Compton wavelength of the particle. The rate is switched off when the particle's charge-to-mass ratio approaches the corresponding extremality bound for black holes, in accordance with a strong form of the Weak Gravity Conjecture (WGC).

    ↳ hep-thastro-ph.HEhep-phJHEP(2025)·20 citations
23. 23*

    Cosmic topology. Part Ic. Limits on lens spaces from circle searches

    Samanta Saha🇺🇸 · Craig J. Copi🇺🇸 · Glenn D. Starkman🇺🇸 · Stefano Anselmi🇮🇹 · Javier Carrón Duque🇪🇸 · Mikel Martin Barandiaran🇪🇸 · Yashar Akrami🇪🇸 · Fernando Cornet-Gomez🇺🇸 · Andrew H. Jaffe🇬🇧 · Arthur Kosowsky🇺🇸 · Deyan P. Mihaylov🇺🇸 · Thiago S. Pereira🇧🇷 · Amirhossein Samandar🇺🇸 · Andrius Tamosiunas (COMPACT Collaboration)🇺🇸

    Cosmic microwave background (CMB) temperature and polarization observations indicate that in the best-fit $\Lambda$ Cold Dark Matter model of the Universe, the local geometry is consistent with at most a small amount of positive or negative curvature, i.e., $|{\Omega }_K|\ll 1$. However, whether the geometry is flat ($E^3$), positively curved ($S^3$) or negatively curved ($H^3$), there are many possible topologies. Among the topologies of $S^3$ geometry, the lens spaces $L(p,q)$, where $p$ and $q$ ($p>1$ and $0<q<p$) are positive integers, are quotients of the covering space of $S^3$ (the three-sphere) by ${\mathbb{Z}}_p$, the cyclic group of order $p$. We use the absence of any pair of circles on the CMB sky with matching patterns of temperature fluctuations to establish constraints on $p$ and $q$ as a function of the curvature scale that are considerably stronger than those previously asserted for most values of $p$ and $q$. The smaller the value of $|{\Omega }_K|$, i.e., the larger the curvature radius, the larger the maximum allowed value of $p$. For example, if $|{\Omega }_K|\simeq 0.05$ then $p\le 9$, while if $|{\Omega }_K|\simeq 0.02$, $p$ can be as high as 24. Future work will extend these constraints to a wider set of $S^3$ topologies.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2025)·8 citations
24. 24*

    Axion-Photon Conversion Signals from Neutron Stars with Spacetime Curvature Accounted for in the Magnetosphere Model

    Jesse Satherley🇳🇿 · Chris Gordon🇳🇿 · Chris Stevens🇳🇿

    Axions are a well-motivated dark matter candidate. They may be detectable from radio line emission due to resonant conversion in neutron star magnetospheres. While radio data collection for this signal has begun, further efforts are required to solidify the theoretical predictions for the resulting radio lines. Usually, the flat spacetime Goldreich-Julian model of the neutron star magnetosphere is used, while a Schwarzschild geometry is assumed for the ray tracing. We assess the impact of incorporating the spacetime curvature into the magnetosphere model. We examine a range of neutron star and axion masses and find an average difference of $37\%$ and $22\%$ in radiated power compared to the standard Goldreich-Julian magnetosphere model for a $1\mu eV$ and $10\mu eV$ mass axion, respectively, in the case of a $2.2M_{\odot }$ mass neutron star. A much lesser difference is found for lower-mass neutron stars, as in that case axion-photon conversion occurs further from the Schwarzschild radius.

    ↳ astro-ph.HEastro-ph.COhep-phPRD(2025)·2 citations
25. 25*

    Cosmological limits on the neutrino mass sum for beyond-$\Lambda$CDM models

    Helen Shao🇺🇸 · Jahmour J. Givans🇺🇸 · Jo Dunkley🇺🇸 · Mathew Madhavacheril🇺🇸 · Frank Qu🇬🇧 · Gerrit Farren🇬🇧 · Blake Sherwin🇬🇧

    The sum of cosmic neutrino masses can be measured cosmologically, as the sub-eV particles behave as `hot' dark matter whose main effect is to suppress the clustering of matter compared to a universe with the same amount of purely cold dark matter. Current astronomical data provide an upper limit on $\Sigma m_{\nu }$ between 0.07 - 0.12 eV at 95% confidence, depending on the choice of data. This bound assumes that the cosmological model is $\Lambda$CDM, where dark energy is a cosmological constant, the spatial geometry is flat, and the primordial fluctuations follow a pure power-law. Here, we update studies on how the mass limit degrades if we relax these assumptions. To existing data from the Planck satellite we add new gravitational lensing data from the Atacama Cosmology Telescope, the new Type Ia Supernova sample from the Pantheon+ survey, and baryonic acoustic oscillation (BAO) measurements from the Sloan Digital Sky Survey and the Dark Energy Spectrosopic Instrument. We find the neutrino mass limit is stable to most model extensions, with such extensions degrading the limit by less than 10%. We find a broadest bound of $\Sigma m_{\nu }<0.19\mathrm{eV}$ at 95% confidence for a model with dynamical dark energy, although this scenario is not statistically preferred over the simpler $\Lambda$CDM model.

    ↳ astro-ph.COhep-phPRD(2025)·33 citations
26. 26*

    Flavor symmetries from modular subgroups in magnetized compactifications

    Tatsuo Kobayashi🇯🇵 · Kaito Nasu🇯🇵 · Ryusei Nishida🇯🇵 · Hajime Otsuka🇯🇵 · Shohei Takada🇯🇵

    We study the flavor structures of zero-modes, which are originated from the modular symmetry on $T_1^2\times T_2^2$ and its orbifold with magnetic fluxes. We introduce the constraint on the moduli parameters by ${\tau }_2=N{\tau }_1$, where ${\tau }_i$ denotes the complex structure moduli on $T_i^2$. Such a constraint can be derived from the moduli stabilization. The modular symmetry of $T_1^2\times T_2^2$ is $SL(2,\mathbb{Z}{)}_{{\tau }_1}\times SL(2,\mathbb{Z}{)}_{{\tau }_2}\subset Sp(4,\mathbb{Z})$ and it is broken to ${\Gamma }_0(N)\times {\Gamma }^0(N)$ by the moduli constraint. The wave functions represent their covering groups. We obtain various flavor groups in these models.

    ↳ hep-thhep-phJHEP(2024)·5 citations
27. 27*

    Redshift Space Distortions corner interacting Dark Energy

    Pietro Ghedini🇮🇹 · Rasmi Hajjar🇪🇸 · Olga Mena🇪🇸

    Despite the fact that the $\Lambda$CDM model has been highly successful over the last few decades in providing an accurate fit to a broad range of cosmological and astrophysical observations, different intriguing tensions and anomalies emerged at various statistical levels. Given the fact that the dark energy and the dark matter sectors remain unexplored, the answer to some of the tensions may rely on modifications of these two dark sectors. This manuscript explores the important role of the growth of structure in constraining non-standard cosmologies. In particular, we focus on the interacting dark energy (IDE) scenario, where dark matter and dark energy interact non-gravitationally. We aim to place constraints on the phenomenological parameters of these alternative models, by considering different datasets related to a number of cosmological measurements, to achieve a complementary analysis. A special emphasis is devoted to redshift space distortion measurements (RSD), whose role in constraining beyond the standard paradigm models has not been recently highlighted. These observations indeed have a strong constraining power, rendering all parameters to their $\Lambda$CDM canonical values, and therefore leaving little room for the IDE models explored here.

    ↳ astro-ph.COhep-phPhys.Dark Univ.(2024)·18 citations
28. 28*

    Primordial regular black holes as all the dark matter. I. Time-radial-symmetric metrics

    Marco Calzà🇮🇹 · Davide Pedrotti🇮🇹 · Sunny Vagnozzi🇮🇹

    Primordial black holes (PBHs) are usually assumed to be described by the Schwarzschild or Kerr metrics, which however feature unwelcome singularities. We study the possibility that PBHs are non-singular objects, considering three phenomenological, regular tr (time-radial)-symmetric space-times (including the well-known Bardeen and Hayward ones), featuring either de Sitter or Minkowski cores. We characterize the evaporation of these PBHs and constrain their abundance from $\gamma$-ray observations. For all three metrics we find that constraints on $f_{\text{pbh}}$, the fraction of dark matter (DM) in the form of PBHs, weaken with respect to the Schwarzschild limits, because of modifications to the PBH temperature and greybody factors. This moves the lower edge of the asteroid mass window down by potentially an order of magnitude or more, leading to a much larger region of parameter space where PBHs can make up all the DM. A companion paper is devoted to non-\textit{tr}-symmetric metrics, including loop quantum gravity-inspired ones. Our work provides a proof-of-principle for the interface between the DM and singularity problems being a promising arena with a rich phenomenology.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2025)·93 citations
29. 29*

    Primordial regular black holes as all the dark matter. II. Non-time-radial-symmetric and loop quantum gravity-inspired metrics

    Marco Calzà🇮🇹 · Davide Pedrotti🇮🇹 · Sunny Vagnozzi🇮🇹

    It is a common belief that a theory of quantum gravity should ultimately cure curvature singularities which are inevitable within General Relativity, and plague for instance the Schwarzschild and Kerr metrics, usually considered as prototypes for primordial black holes (PBHs) as dark matter (DM) candidates. We continue our study, initiated in a companion paper, of non-singular objects as PBHs, considering three regular non-tr (non-time-radial)-symmetric metrics, all of which are one-parameter extensions of the Schwarzschild space-time: the Simpson-Visser, Peltola-Kunstatter, and D'Ambrosio-Rovelli space-times, with the latter two motivated by loop quantum gravity. We study evaporation constraints on PBHs described by these regular metrics, deriving upper limits on $f_{\text{pbh}}$, the fraction of DM in the form of PBHs. Compared to their Schwarzschild counterparts, these limits are weaker, and result in a larger asteroid mass window where all the DM can be in the form of PBHs, with the lower edge moving potentially more than an order of magnitude. Our work demonstrates as a proof-of-principle that quantum gravity-inspired space-times can simultaneously play an important role in the resolution of singularities and in the DM problem.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2025)·88 citations
30. 30*

    Vacuum Radiation Pressure Fluctuations on Electrons

    L. H. Ford🇺🇸

    This paper is a continuation of a study of the properties and applications of quantum stress tensor fluctuations. Here we treat the vacuum fluctuations of the electromagnetic energy-momentum flux operator which as been averaged in space and time. The probability distribution of these fluctuations depends upon the details of this averaging and may allow fluctuations very large compared to the variance. The possibility of detecting their effects on electrons will be considered. The averaging of the flux operator will arise from the interaction of an electron with a wave packet containing real photons, The vacuum radiation pressure fluctuations can exert a force on the electron in any direction, in contrast to the effect of scattering by real photons. Some numerical estimates of the effect will be given.

    ↳ hep-thhep-phquant-phPRD(2024)·1 citation
31. 31*

    Exploring cosmological gravitational wave backgrounds through the synergy of LISA and ET

    Alisha Marriott-Best🇬🇧 · Debika Chowdhury🇮🇳 · Anish Ghoshal🇵🇱 · Gianmassimo Tasinato🇬🇧

    The gravitational wave (GW) interferometers LISA and ET are expected to be functional in the next decade(s), possibly around the same time. They will operate over different frequency ranges, with similar integrated sensitivities to the amplitude of a stochastic GW background (SGWB). We investigate the synergies between these two detectors, in terms of a multi-band detection of a cosmological SGWB characterised by a large amplitude, and a broad frequency spectrum. We develop the notion of integrated sensitivity and propose a novel signal-to-noise (SNR) optimal for characterization of the geometrical properties of the interferometer systems of LISA and ET operating simultaneously. By investigating various examples of SGWBs, such as those arising from cosmological phase transition, cosmic string, primordial inflation, we show that LISA and ET operating together will have the opportunity to assess more effectively the characteristics of the GW spectrum produced by the same cosmological source, but at separate frequency scales. Moreover, the two experiments in tandem can be sensitive to features of early universe cosmic expansion before big-bang nucleosynthesis (BBN), which affects the SGWB frequency profile, and which would not be possible to detect otherwise, since two different frequency ranges correspond to two different pre-BBN (or post-inflationary) epochs. Besides considering the GW spectrum, we additionally undertake a preliminary study of the sensitivity of LISA and ET to soft limits of higher order tensor correlation functions. Given that these experiments operate at different frequency bands, their synergy constitutes an ideal direct probe of squeezed limits of higher order GW correlators, which can not be measured operating with a single instrument only.

    ↳ astro-ph.COhep-phhep-thPRD(2025)·13 citations
32. 32*

    Gravitational radiation from binary systems in Unimodular gravity

    Indranil Chakraborty🇮🇳 · Soumya Jana🇮🇳 · Subhendra Mohanty🇮🇳

    Unimodular gravity (UG) is classically considered identical to General Relativity (GR). However, due to restricted diffeomorphism symmetry, the Bianchi identites do not lead to the conservation of energy-momentum tensor. Thus, the conservation of energy-momentum tensor needs to be separately assumed in order to reconcile with GR. Relaxing this assumption, one finds that the conservation violation can lead to differences with GR, which can be subsequently examined in astrophysical and cosmological scenarios. To this end, we examine the predictions of UG in the context of binary systems emitting gravitational radiation. Primarily, we show how the field equations involve a diffusion function which quantifies the measure of non-conservation. Due to this violation, the dispersion relation is modified. Incorporating these changes, we provide an expression for the energy loss by the binaries, which reduces to Peters-Mathews result in the GR limit. Using binary pulsar data, we constrain the theory parameter $\zeta$ (which signifies non-conservation) by determining the rate of orbital decay. The strongest constrain on $\zeta$ comes out to be $|\zeta |\le 5\times 10^{-4}$ which is better by an order of magnitude than an existing equivalent constraint coming from the tidal deformability of the neutron stars.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2025)·2 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.