Mon·Jul 8, 2024Monday·July 8, 2024

1. 01*

   CP Violation of Baryon Decays with $N\pi$ Scatterings

   Jian-Peng Wang🇨🇳 · Fu-Sheng Yu🇨🇳

   There is a long-standing puzzle that the CP violation (CPV) in the baryon systems has never been well established in experiments, while the CPV of mesons have been observed by decades. In this paper, we propose that the CPV of baryon decays can be generated with the rescatterings of a nucleon and a pion into some final states, i.e. $N\pi \to N\pi$ or $N\pi \pi$. Benefited by the fruitful data of $N\pi$ scatterings, we can model-independently analyse the strong phases of $b$-baryon decays using the partial wave amplitudes of $N\pi$ scatterings. Avoiding the most difficult problem of non-perturbative dynamics, it makes a great advantage to predict the CPV of baryon decays with a relatively reliable understanding of the decay dynamics. We study the processes of ${\Lambda }_b^0\to (p{\pi }^{+}{\pi }^{-})h^{-}$ and $(p{\pi }^0)h^{-}$ with $h=\pi$ or $K$. It is found that the global CPV of the above processes in the invariant mass regions of $N\pi$ scatterings are at the order of several percent. More importantly, the local CPV in some regions of the Dalitz plots can reach the order of $10\%$, or be even larger. Considering the predicted results and the experimental data samples, we strong suggest to measure the CPV of ${\Lambda }_b^0\to (p{\pi }^{+}{\pi }^{-})K^{-}$, which has a large possibility to achieve the first observation of CPV in the baryon system.

   hep-phhep-exCPC(2024)·25 citations
2. 02*

   $\lambda$ and $\rho$ Regge trajectories for hidden bottom and charm tetraquarks $(Qq)(\bar{Q}{\bar{q}}^{\prime })$

   Jia-Qi Xie🇨🇳 · He Song🇨🇳 · Xia Feng🇨🇳 · Jiao-Kai Chen🇨🇳

   We propose the Regge trajectory relations for the heavy tetraquarks $(Qq)(\bar{Q}{\bar{q}}^{\prime })$ $(Q=b,c;q,q^{\prime }=u,d,s)$ with hidden bottom and charm. By employing the new relations, both the $\lambda$-trajectories and the $\rho$-trajectories for the tetraquarks $(Qq)(\bar{Q}{\bar{q}}^{\prime })$ can be discussed. The masses of the $\lambda$-mode excited states and the $\rho$-mode excited states are estimated, and they agree with other theoretical predictions. We show that the behaviors of the $\rho$-trajectories are different from those of the $\lambda$-trajectories. The $\rho$-trajectories behave as $M\sim x_{\rho }^{1/2}$ $(x_{\rho }=n_r,l)$ while the $\lambda$-trajectories behave as $M\sim x_{\lambda }^{2/3}$ $(x_{\lambda }=N_r,L)$. Moreover, the Regge trajectory behaviors for other types of tetraquarks are investigated based on the spinless Salpeter equation. We show that both the $\lambda$-trajectories and the $\rho$-trajectories are concave downward in the $(M^2,x)$ plane. The Regge trajectories for the tetraquarks containing the light diquark and/or the light antidiquark also are concave in the $(M^2,x)$ plane when the masses of the light constituents are included and the confining potential is linear.

   hep-phPRD(2024)·10 citations
3. 03*

   A new possible way to detect Axion Anti-quark Nuggets

   Ionel Lazanu🇷🇴 · Mihaela Parvu🇷🇴

   The axion anti-quark nugget (A$\bar{\mathrm{Q}}$N) model was developed to explain in a natural way the asymmetry between matter and antimatter in Universe. In this hypothesis, a similitude between the dark and the visible components exists. The lack of observability of any type of dark matter up to now, in particular A$\bar{\mathrm{Q}}$Ns, requires finding new ways of detecting these particles, if they exist. In spite of strong interaction with visible matter, for such objects a very small ratio of cross section to mass is expected and thus huge detector systems are necessary. This paper presents a new idea for the direct detection of the A$\bar{\mathrm{Q}}$Ns using minerals as natural rock deposits acting as paleo-detectors, where the latent signals of luminescence produced by interactions of A$\bar{\mathrm{Q}}$Ns are registered and can be identified as an increased and symmetrical deposited dose. The estimates were made for minerals widely distributed on Earth, for which the TL signal is intense and if the thermal conditions are constant and with low temperatures, the lifetime of the latent signals is kept for geological time scales.

   hep-phphysics.ins-detSymmetry(2024)·1 citation
4. 04*

   Reconstructing a Heavy Neutral Lepton at the LHC

   Pablo de la Torre🇪🇸 · Manuel Masip🇪🇸 · Fuensanta Vilches🇪🇸

   Heavy lepton singlets $N$ slightly mixed with a standard neutrino ${\nu }_{\ell }$ are usually searched for at the LHC in the trilepton plus $p_{\mathrm{T}}^{\mathrm{miss}}$ channel: $pp\to W^{+}\to {\ell }^{+}N$ with $N\to {\ell }^{-}{W}^{+}\to {\ell }^{-}{\ell }^{\prime +}\nu$. We show that, although the longitudinal momentum of the final $\nu$ escapes detection, the mass of the heavy lepton can be reconstructed. While this possibility has not been considered in recent LHC searches, we find that the search for a mass peak could systematically improve the current collider bounds on the mixing $|V_{\ell N}{|}^2$ for any mass $m_N\ge M_W$.

   hep-phhep-exJHEP(2025)·2 citations
5. 05*

   Nonlinear Schwinger mechanism in QCD, and Fredholm alternatives theorem

   M. N. Ferreira🇨🇳 · J. Papavassiliou🇪🇸

   We present a novel implementation of the Schwinger mechanism in QCD, which fixes uniquely the scale of the effective gluon mass and streamlines considerably the procedure of multiplicative renormalization. The key advantage of this method stems from the nonlinear nature of the dynamical equation that generates massless poles in the longitudinal sector of the three-gluon vertex. An exceptional feature of this approach is an extensive cancellation involving the components of the integral expression that determines the gluon mass; it is triggered once the Schwinger-Dyson equation of the pole-free part of the three-gluon vertex has been appropriately exploited. It turns out that this cancellation is driven by the so-called Fredholm alternatives theorem, which operates among the set of integral equations describing this system. Quite remarkably, in the linearized approximation this theorem enforces the exact masslessness of the gluon. Instead, the nonlinearity induced by the full treatment of the relevant kernel evades this theorem, allowing for the emergence of a nonvanishing mass. The numerical results obtained from the resulting equations are compatible with the lattice findings, and may be further refined through the inclusion of the remaining fundamental vertices of the theory.

   hep-phhep-lathep-thnucl-thEPJC(2024)·4 citations
6. 06*

   Radiative decays of $P$-wave bottom baryons from light-cone sum rules

   Xuan Luo🇨🇳 · Hui-Min Yang🇨🇳 · Hua-Xing Chen🇨🇳

   We carry out a comprehensive investigation on the radiative decays of $P$-wave bottom baryons using the light-cone sum rule method. We analyze their electromagnetic transitions into ground-state bottom baryons together with a photon. Together with their mass spectra and strong decays investigated in Refs. \cite{Yang:2020zrh,Tan:2023opd}, a rather complete QCD sum rule study has been done to understand the $P$-wave singly bottom baryons within the framework of heavy quark effective theory. As summarized in Tables~\ref{tab:candidate}/\ref{tab:candidate6f}, some $P$-wave bottom baryons have limited strong decay widths so that their radiative decay widths become non-negligible. We propose to study these excited bottom baryons and their radiative decays in the future Belle-II, BESIII, and LHCb experiments.

   hep-phPRD(2025)·6 citations
7. 07*

   Internal structure of the $T_{cc}(3875{)}^{+}$ from its light-quark mass dependence

   Michael Abolnikov🇩🇪 · Vadim Baru🇩🇪 · Evgeny Epelbaum🇩🇪 · Arseniy A. Filin🇩🇪 · Christoph Hanhart🇩🇪 · Lu Meng🇩🇪

   We employ a chiral effective field theory-based approach to connect $D{D}^{\ast }$ scattering observables at the physical and variable pion masses accessible in lattice QCD simulations. We incorporate all relevant scales associated with three-body $DD\pi$ dynamics and the left-hand cut induced by the one-pion exchange for pion masses higher than the physical one, as required by analyticity and unitarity. By adjusting the contact interactions to match experimental data at the physical pion mass and lattice finite-volume energy levels at $m_{\pi }=280$ MeV, we predict the trajectory of the $T_{cc}$ pole as a function of the pion mass, finding it consistent with the hadronic-molecule scenario. In particular, we find that the explicit treatment of the one-pion exchange has a pronounced effect on the pole trajectory for $m_{\pi }\gtrsim 230$ MeV by pushing it into the complex energy plane.

   hep-phhep-exhep-latnucl-thPLB(2025)·31 citations
8. 08*

   Electroweak corrections to Higgs boson pair production: The top-Yukawa and self-coupling contributions

   Gudrun Heinrich🇩🇪 · Stephen Jones🇬🇧 · Matthias Kerner🇩🇪 · Thomas Stone🇬🇧 · Augustin Vestner🇩🇪

   We present results for the Yukawa-enhanced and Higgs self-coupling type electroweak corrections to di-Higgs production in gluon fusion. The calculation of the corresponding four-scale, two-loop amplitude is carried out retaining the exact symbolic dependence on all masses and scales during the reduction to master integrals. The resulting integrals are then evaluated at high precision using both the series expansion of the differential equations and sector decomposition. Differential cross sections for the di-Higgs invariant mass and the transverse momentum of a Higgs boson are shown, where we find that the corrections are most pronounced at low invariant mass and transverse momentum.

   hep-phJHEP(2024)·40 citations
9. 09*

   Neutrinoless Double Beta Decay from Scalar Leptoquarks: Interplay with Neutrino Mass and Flavor Physics

   P. S. Bhupal Dev🇺🇸 · Srubabati Goswami🇮🇳 · Chayan Majumdar🇬🇧 · Debashis Pachhar🇮🇳

   We perform a comprehensive analysis of neutrinoless double beta decay and its interplay with low-energy flavor observables in a radiative neutrino mass model with scalar leptoquarks $S_1(\bar{3},1,1/3)$ and ${\tilde{R}}_2(3,2,1/6)$. We carve out the parameter region consistent with constraints from neutrino mass and mixing, collider searches, as well as measurements of several flavor observables, such as muon and electron anomalous magnetic moments, charged lepton flavor violation and rare (semi)leptonic kaon and $B$-meson decays, including the recent anomalies in $R_{D^{(\ast )}}$ and $B\to K\nu \bar{\nu }$ observables. We perform a global analysis to all existing constraints and show the (anti)correlations between all relevant Yukawa couplings satisfying these restrictions. We find that the most stringent constraint on the parameter space comes from $\mu \to e$ conversion in nuclei and $K^{+}\to {\pi }^{+}\nu \bar{\nu }$ decay. We also point out a tension between the muon and electron $(g-2)$ anomalies in this context. Taking benchmark values from the combined allowed regions, we study the implications for neutrinoless double beta decay including both the canonical light neutrino and the leptoquark contributions. We find that for normal ordering of neutrino masses, the leptoquark contribution removes the cancellation region that occurs for the canonical case. The effective mass in presence of leptoquarks can lie in the desert region between the standard normal and inverted ordering cases, and this can be probed in future ton-scale experiments like LEGEND-1000 and nEXO.

   hep-phJHEP(2025)·16 citations
10. 10*

    High-Energy Neutrinos From Millicharged Dark Matter Annihilation in the Sun

    Asher Berlin🇺🇸 · Dan Hooper🇺🇸

    Millicharged dark matter particles can be efficiently captured by the Sun, where they annihilate into tau leptons, leading to the production of high-energy neutrinos. In contrast to the Earth, the high temperature of the Sun suppresses the fraction of millicharged particles that are bound to nuclei, allowing for potentially high annihilation rates. We recast existing constraints from the IceCube Neutrino Observatory and use this information to place new limits on the fraction of the dark matter that is millicharged. This analysis excludes previously unexplored parameter space for masses of $m_{\chi }\sim (5-100)\text{GeV}$, charges of $q_{\chi }\sim 10^{-3}-10^{-2}$, and fractional abundances as small as $f_{{}_{\text{DM}}}\sim 10^{-5}$.

    hep-phastro-ph.HEPRD(2024)·13 citations
11. 11*

    Ultimate light-shining-through-a-wall experiments to establish QCD axions as the dominant form of dark matter

    Sebastian Hoof🇮🇹 · Joerg Jaeckel🇩🇪 · Giuseppe Lucente🇩🇪

    Establishing the axion as the dark matter (DM) particle after a haloscope discovery typically requires follow-up experiments to break the degeneracy between the axion's coupling to photons and its local DM abundance. Given that a discovery would justify more significant investments, we explore the prospects of ambitious light-shining-through-a-wall (LSW) setups to probe the QCD axion band. Leveraging the excellent mass determination in haloscopes, we show how to design LSW experiments with lengths on the order of 100 km and suitably aligned magnetic fields with apertures of around 1 m to reach well-motivated axion models across up to four orders of magnitude in mass. Beyond presenting a concrete plan for post-discovery experimental efforts, we briefly discuss complementary experiments and future directions beyond LSW experiments.

    hep-phhep-exPRD(2025)·10 citations
12. 12*

    Gluon to $q\bar{q}$ antenna in anisotropic QCD matter: spin-polarized and azimuthal jet observables

    João Barata🇺🇸 · Carlos A. Salgado🇪🇸 · João M. Silva🇵🇹

    We study the production of a quark-antiquark antenna in the presence of a dense and anisotropic QCD medium. We assume the antenna to originate from an unpolarized gluon state, and consider both massless and massive final states. The medium anisotropy is captured by allowing the jet quenching coefficient to take different magnitudes in orthogonal directions with respect to the jet axis. We find that the final particle distribution is sensitive to the medium anisotropy, and more importantly, that this effect couples directly to the helicity/spin of the final states. We propose to look into these effects by performing a Fourier decomposition of the particle distribution inside the jet. In our medium model, we find that the spin independent terms contribute to the even harmonics of the cosine series. The helicity/spin dependence enters only through the sine Fourier series. We further explore the spin dependence by examining the degree of polarization of the final states in different directions. Our results indicate that the anisotropies present in the QCD matter produced in heavy ion collisions can be probed by studying azimuthal and spin observables inside jets.

    hep-phhep-exnucl-thJHEP(2024)·30 citations
13. 13*

    Phasing out of Darkness: From Sterile Neutrino Dark Matter to Neutrino Masses via Time-Dependent Mixing

    Florian Goertz🇩🇪 · Maya Hager🇩🇪 · Giorgio Laverda🇵🇹 · Javier Rubio🇪🇸

    Sterile neutrinos are a compelling candidate for generating neutrino masses and for elucidating the nature of dark matter. Astrophysical X-ray constraints on sterile neutrino dark matter decays, however, largely exclude the active-sterile mixing required to produce simultaneously the correct left-handed neutrino spectrum and keV-scale right-handed neutrino dark matter within a type-I seesaw framework. In this study, we demonstrate how these X-ray constraints can be circumvented through a time-dependent approach, thereby reviving a broad range of active-sterile mixing scenarios. Our minimal model incorporates two right-handed neutrinos, which form a two-component dark matter candidate, and an auxiliary scalar field that experiences a very late and still ongoing phase transition, leading to the spontaneous breaking of a global $U(1{)}_N$ symmetry. Prior to this phase transition, only the right-handed neutrinos are massive, while the left-handed neutrinos remain massless because of the scalar field's vanishing expectation value. As the phase transition develops, the growing expectation value of the scalar field increases the active-sterile mixing, thereby opening dark matter decay channels and inducing neutrino masses. The time dependence allows the scenario to be consistent with X-ray constraints as well as current measurements of left-handed neutrino masses. The anticipated level of active-sterile mixing today is within the detection capabilities of the forthcoming TRISTAN (KATRIN) tritium-beta decay project. Additionally, cosmological surveys such as DESI or EUCLID and supernova neutrino observations can test the prediction of massless left-handed neutrinos prior to the phase transition.

    hep-phastro-ph.COhep-exJHEP(2025)·15 citations
14. 14*

    Probing the equilibration of the QCD matter created in heavy-ion collisions with dileptons

    Xiang-Yu Wu🇨🇦 · Lipei Du🇨🇦 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦

    A systematic study of intermediate invariant mass dilepton production in Pb+Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV is performed, using next-to-leading-order (NLO) thermal QCD dilepton emission rates with a multistage dynamical approach which includes event-by-event IP-Glasma initial conditions, relativistic viscous fluid dynamics, and a hadronic afterburner. Considering dilepton yield and anisotropic flow, special attention is paid to the out-of-equilibrium aspects, both thermal and chemical, and to the contribution of the Drell-Yan process. The relative contribution of each of those different channels to dilepton observables is calculated and discussed.

    ↳ nucl-thhep-phnucl-exPRC(2024)·23 citations
15. 15*

    Measurement of the differential Higgs boson production cross sections in ATLAS and CMS experiments

    Abdollah Mohammadi (on behalf of ATLAS and CMS collaborations)🇺🇸

    A comprehensive set of studies has been conducted to measure the fiducial differential cross sections of Higgs boson production by the ATLAS and CMS experiments. These analyses are based on proton-proton collision data collected by both experiments at the CERN LHC, with a center-of-mass energy of 13 TeV. The data sample corresponds to an integrated luminosity of up to 140 fb${}^{-1}$. Fiducial Differential cross sections are measured for various observables sensitive to the production and decay of the Higgs boson. All measurements align with Standard Model predictions. The results are used to constrain potential anomalous interactions between the Higgs boson and other Standard Model particles.

    ↳ hep-exhep-ph0 citations
16. 16*

    Constraints on blue and red tilted primordial power spectra using dwarf galaxy properties

    Ariane Dekker🇺🇸 · Andrey Kravtsov🇺🇸

    Although the standard $\Lambda$+Cold Dark Matter ($\Lambda$CDM) model is well tested on large scales, the primordial power spectrum may deviate from the $\Lambda$CDM spectrum on small scales due to specific dark matter properties or alternative inflationary models. These deviations affect the formation of dark matter structure, which subsequently leads to different observable properties of galaxies. In this work, we study the impact of a blue and red tilted power spectrum on the central density of dwarf galaxies. To do this, we model densities of dwarf galaxies using a combination of high-resolution numerical simulations and galaxy formation model. The model galaxies in $\Lambda$CDM are consistent with observations of 41 faint dwarf satellite galaxies of the Milky Way. The deviations from the $\Lambda$CDM power spectrum are constrained by the central matter densities of dwarf galaxies, which set stringent constraints on the possible small-scale tilt of the primordial power spectrum, improving on the current limits. Moreover, similar analysis can be applied to test any feature in the power spectrum at small scales between $k\sim 10-100$~Mpc${}^{-1}$.

    ↳ astro-ph.COhep-phPRD(2025)·20 citations
17. 17*

    Fermion Self-Energy and Effective Mass in a Noisy Magnetic Background

    Jorge David Castaño-Yepes🇨🇱 · Enrique Muñoz🇨🇱

    In this article, we consider the propagation of QED fermions in the presence of a classical background magnetic field with white-noise stochastic fluctuations. The effects of the magnetic field fluctuations are incorporated into the fermion and photon propagators in a quasi-particle picture, which we developed in previous works using the {\it replica trick}. By considering the strong-field limit, here we explicitly calculate the fermion self-energy involving radiative contributions at first-order in ${\alpha }_{\text{em}}$, in order to obtain the noise-averaged mass of the fermion propagating in the fluctuating magnetized medium. Our analytical results reveal a leading double-logarithmic contribution $\sim {\left[\ln \left(|eB|/m^2\right)\right]}^2$ to the mass, with an imaginary part representing a spectral broadening proportional to the magnetic noise auto-correlation $\Delta$. While a uniform magnetic field already breaks Lorentz invariance, inducing the usual separation into two orthogonal subspaces (perpendicular and parallel with respect to the field), the presence of magnetic noise further breaks the remaining symmetry, thus leading to distinct spectral widths associated with fermion and anti-fermion, and their spin projection in the quasi-particle picture.

    ↳ hep-thhep-phPRD(2024)·11 citations
18. 18*

    Detecting the dark sector through scalar-induced gravitational waves

    Xiao-Bin Sui🇨🇳 · Jing Liu🇨🇳 · Xing-Yu Yang🇰🇷 · Rong-Gen Cai🇨🇳

    We investigate the evolution of cosmological scalar perturbations in the case that the background radiation is weakly coupled to a light scalar field $\varphi$. The light scalar $\varphi$ is a homogeneous background field with a large initial value. In the radiation-dominated Universe, the coupling term introduces an effective mass to $\varphi$ and the background ultra-relativistic particles. The oscillations of $\varphi$ result in the periodic change of the equation of state parameter and the sound speed, which provides a novel mechanism to amplify subhorizon scalar perturbations through parametric resonance. The amplification of scalar perturbations leads to a stochastic gravitational-waves background~(SGWB) expected to be observed by multiband gravitational wave observers. The observation of the SGWB helps to determine the initial value of $\varphi$ and the coupling strength of the interaction. This mechanism is generally applicable to the interactions that introduce an effective mass, and we take the interaction between $\varphi$ and electrons as a concrete example to illustrate the result. We find that under the condition that the coupling coefficient $\lambda =10^{-16}$ and the initial value ${\varphi }_i=10^{18}$ GeV, the resulting SGWB spectrum is expected to be observed by the future observers including LISA, $Taiji$, DECIGO and BBO.

    ↳ astro-ph.COgr-qchep-phPRD(2024)·7 citations
19. 19*

    Study of the neutrino-oxygen cross sections of the charged-current reaction 16O(${\bar{\nu }}_e,e^{+}$)16N(0 MeV,$2^{-}$) and the neutral-current reaction 16O($\nu ,\nu$')16O(12.97/12.53 MeV,$2^{-}$), producing high-energy gamma rays

    Makoto Sakuda🇯🇵 · Toshio Suzuki🇯🇵 · Ken'ichiro Nakazato🇯🇵 · Hideyuki Suzuki🇯🇵

    In the previous work, we discussed the cross section and the detection of 4.4-MeV $\gamma$ rays produced in the neutrino neutral-current (NC) reaction ${}^{16}$O($\nu ,{\nu }^{\prime }$)${}^{16}$O(12.97 MeV and 12.53 MeV, $2^{-}$) in a water Cherenkov detector at the low energy below 100 MeV. In this report, we further investigated both the charged-current (CC) reaction ${}^{16}$O(${\bar{\nu }}_e,e^{+}$)${}^{16}$N(0 MeV, $2^{-}$) and the NC reaction${}^{16}$O($\nu ,{\nu }^{\prime }$)${}^{16}$O(12.97 MeV and 12.53 MeV, $2^{-}$), producing high-energy $\gamma$ rays, in which the more solid identification of the reactions can be applied via the coincidence method.

    ↳ nucl-thhep-phnucl-exPTEP(2024)·0 citations
20. 20*

    Observational prospects of self-interacting scalar superradiance with next-generation gravitational-wave detectors

    Spencer Collaviti🇨🇭 · Ling Sun🇦🇺 · Marios Galanis🇨🇦 · Masha Baryakhtar🇺🇸

    Current- and next-generation gravitational-wave observatories may reveal new, ultralight bosons. Through the superradiance process, these theoretical particle candidates can form clouds around astrophysical black holes and result in detectable gravitational-wave radiation. In the absence of detections, constraints$-$contingent on astrophysical assumptions$-$have been derived using LIGO-Virgo-KAGRA data on boson masses. However, the searches for ultralight scalars to date have not adequately considered self-interactions between particles. Self-interactions that significantly alter superradiance dynamics are generically present for many scalar models, including axion-like dark matter candidates and string axions. We implement the most complete treatment of particle self-interactions available to determine the gravitational-wave signatures expected from superradiant scalar clouds and revisit the constraints obtained in a past gravitational-wave search targeting the black hole in Cygnus X-1. We also project the reach of next-generation gravitational-wave observatories to scalar particle parameter space in the mass-coupling plane. We find that while proposed observatories have insufficient reach to self-interactions that can halt black hole spin-down, next-generation observatories are essential for expanding the search beyond gravitational parameter space and can reach a mass and interaction scale of $\sim 10^{-13}-10^{-12}$ eV/c${}^2$ and $\gtrsim 10^{17}$ GeV, respectively.

    ↳ gr-qcastro-ph.HEhep-phClass.Quant.Grav.(2025)·32 citations
21. 21*

    On the overlap reduction function of pulsar timing array searches for gravitational waves in modified gravity

    Nina Cordes🇩🇪 · Andrea Mitridate🇩🇪 · Kai Schmitz🇩🇪 · Tobias Schröder🇩🇪 · Kim Wassner🇩🇪

    Pulsar Timing Array (PTA) searches for gravitational waves (GWs) aim to detect a characteristic correlation pattern in the timing residuals of galactic millisecond pulsars. This pattern is described by the PTA overlap reduction function (ORF) \Gamma_ab(\xi_ab), which is known as the Hellings--Downs (HD) curve in general relativity (GR). In theories of modified gravity, the HD curve often receives corrections. Assuming, e.g., a subluminal GW phase velocity, one finds a drastically enhanced ORF in the limit of small angular separations between pulsar a and pulsar b in the sky, \xi_ab --> 0. In particular, working in harmonic space and performing an approximate resummation of all multipole contributions, the auto correlation coefficient \Gamma_aa seems to diverge. In this paper, we confirm that this divergence is unphysical and provide an exact and analytical expression for \Gamma_aa in dependence of the pulsar distance L_a and the GW phase velocity v_ph. In the GR limit and assuming a large pulsar distance, our expression reduces to \Gamma_aa = 1. In the case of subluminal phase velocity, we show that the regularization of the naive divergent result is a finite-distance effect, meaning that \Gamma_aa scales linearly with fL_a, where f is the GW frequency. For superluminal phase velocity (subluminal group velocity), which is relevant in the case of massive gravity, we correct an earlier analytical result for \Gamma_ab. Our results pave the way for fitting modified-gravity theories with nonstandard phase velocity to PTA data, which requires a proper understanding of the auto correlation coefficient \Gamma_aa.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-phClass.Quant.Grav.(2025)·13 citations
22. 22*

    The Nature of the High-energy Gamma-Ray Radiation Associated with the High-redshift Blazar B3 1343+451

    Fan Wu · Wen Hu🇨🇳 · Benzhong Dai🇨🇳

    High-redshift blazars are the most powerful extragalactic astrophysical sources ever detected in the high-energy gamma-ray band. In this study, we present a temporal and spectral analysis of the high-redshift blazar B3 1343+451 based on 14 years of Fermi-LAT observations, spanning from 2008 August 4 to 2022 June 6 (MJD 54686-59733). We extract a seven-day binned $\gamma$-ray light curve in the energy range 0.1--500 GeV and identify seven outburst periods with a peak flux of $>4.32\times 10^{-7}\mathrm{ph}\cdot \mathrm{c}{\mathrm{m}}^{-2}\cdot {\mathrm{s}}^{-1}$. The highest seven day flux (above 100 MeV) reaches $(8.06\pm 0.56)\times 10^{-7}\mathrm{erg}\mathrm{c}{\mathrm{m}}^{-2}{\mathrm{s}}^{-1}$ on MJD = 56,177.16, which is 10 times higher than the flux in the quiescent period. To understand the properties of distant blazar jets, we employ a standard one-zone leptonic scenario and model the multiwavelength spectral energy distributions of one quiescent and seven flaring periods. We find that the $\gamma$-ray spectrum is better reproduced if we assume that the dissipation region of the jet, $R_{\mathrm{diss}}$, is located within the molecular torus, where infrared emission is the dominant external photon field. We infer that the jets in higher-redshift blazars have larger power and kinetic energy, where the kinetic energy is significantly greater than the radiation power, and the jet production efficiency suggests that we need to lower the accretion efficiency. These results imply that B3 1343+451 may have a standard thin disk surrounding its massive black hole, and the jets of B3 1343+451 may not be fully explained by the Blandford--Payne process.

    ↳ astro-ph.HEhep-phApJ(2024)·3 citations
23. 23*

    A unified approach to coupled homogeneous linear wave propagation in generic gravity

    Lucas T. Santana · João C. Lobato · Ribamar R. R. Reis🇧🇷 · Maurício O. Calvão

    Wave propagation is a common occurrence in all of physics. A linear approximation provides a simpler way to describe various fields related to observable phenomena in laboratory physics as well as astronomy and cosmology, allowing us to probe gravitation through its effect on the trajectories of particles associated with those fields. This paper proposes a unified framework to describe the wave propagation of a set of interacting tensor fields that obey coupled homogeneous linear second-order partial differential equations for arbitrary curved spacetimes, both Lorentzian and metric-affine. We use JWKB Ansätze for all fields, written in terms of a perturbation parameter proportional to a representative wavelength among them, deriving a set of hierarchical algebraic and differential equations that link the fields' phases and different order amplitudes. This allows us to reobtain the well-known laws of geometrical optics and beyond geometrical optics in a generalized form, showing that these laws are independent of the rank of the fields involved. This is true as long as what we refer to as the kinetic tensor of a given field satisfies a set of diagonality conditions, which further imply a handful of simplifications on the transport equations obtained in the subleading orders of the JWKB Ansätze. We explore these results in several notable examples in Lorentzian and metric-affine spacetimes, illustrating the reach of our derivations in general relativity, reduced Horndeski theories, spacetimes with completely antisymmetric torsion and Weyl spacetimes. The formalism presented herein lays the groundwork for the study of rays associated with different types of waves in curved spacetimes and provides the tools to compute modifications to their brightness evolution laws, consequential distance duality relations, and beyond geometrical optics phenomena.

    ↳ gr-qchep-phPRD(2024)·1 citation
24. 24*

    High-energy neutrino signatures from pulsar remnants of binary neutron-star mergers: coincident detection prospects with gravitational waves

    Mainak Mukhopadhyay🇺🇸 · Shigeo S. Kimura🇯🇵 · Brian D. Metzger🇺🇸

    Binary neutron-star (BNS) mergers are accompanied by multi-messenger emissions, including gravitational wave (GW), neutrino, and electromagnetic signals. Some fraction of BNS mergers may result in a rapidly spinning magnetar as a remnant, which can enhance both the EM and neutrino emissions. In this study, we model the neutrino emissions from such systems and discuss the prospects for detecting the neutrinos coincident with GW signatures. We consider a scenario where a magnetar remnant drives a pulsar wind using its spin energy. The wind interacts with the surrounding kilonova ejecta, forming a nebula filled with non-thermal photons. Ions and nuclei extracted from the magnetar's surface can be accelerated in the polar-cap and the termination-shock regions. We investigate the neutrino fluences resulting from photomeson interactions, where accelerated CR protons interact with the photons in the nebula. Our findings indicate that the peak neutrino fluence is $\sim 10^{-2}\mathrm{GeV}\mathrm{c}{\mathrm{m}}^{-2}$ for a source at $40$ Mpc, which is reached approximately $\mathcal{O}(1-10\mathrm{days})$ post merger. Finally, we examine the potential for GW-triggered stacking searches with IceCube-Gen2 using next-generation GW detectors such as the Cosmic Explorer (CE) and the Einstein Telescope (ET). We conclude that, assuming an optimistic neutrino emission model, a combination of CE+ET would offer a high probability of neutrino detection from these sources within an operational timescale of $\sim 20$ years. In case of non-detection, $2\sigma$ level constraints on model parameters can be established within similar joint operation timescales.

    ↳ astro-ph.HEhep-phApJ(2025)·14 citations
25. 25*

    Neutrino quantum kinetics in two spatial dimensions

    Marie Cornelius🇩🇰 · Shashank Shalgar🇩🇰 · Irene Tamborra🇩🇰

    Our understanding of neutrino flavor conversion in the innermost regions of core-collapse supernovae and neutron star mergers is mostly limited to spherically symmetric configurations that facilitate the numerical solution of the quantum kinetic equations. In this paper, we simulate neutrino quantum kinetics within a (2+1+1) dimensional setup: we model the flavor evolution during neutrino decoupling from matter in two spatial dimensions, one neutrino momentum variable, and time; taking into account non-forward neutral current and charged current collisions of neutrinos with the matter background, as well as neutrino advection. In order to mimic fluctuations in the neutrino emission and matter background, and explore their effect on the flavor evolution, we introduce perturbations in the collision term as well as in the vacuum term of the Hamiltonian. Because of such perturbations, the initial symmetry of the neutrino field across the simulation annulus is broken and flavor conversion is qualitatively affected, with regions of larger flavor conversion alternating across the simulation annulus. In addition, neutrino advection is responsible for spreading flavor waves across neighboring spatial regions. Although based on a simplified setup, our findings highlight the importance of modeling neutrino quantum kinetics in multi-dimensions to assess the impact of neutrinos on the physics of compact astrophysical sources and nucleosynthesis.

    ↳ astro-ph.HEhep-phJCAP(2024)·13 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.