Wed·Jun 12, 2024Wednesday·June 12, 2024

1. 01*

   Theory of neutrino fast flavor evolution. Part I. Linear response theory and stability conditions

   Damiano F. G. Fiorillo🇩🇰 · Georg G. Raffelt🇩🇪

   Neutrino-neutrino refraction leads to collective flavor evolution that can include fast flavor conversion, an ingredient still missing in numerical simulations of core-collapse supernovae. We provide a theoretical framework for the linear regime of this phenomenon using the language of response theory. In analogy to electromagnetic waves, we introduce a flavor susceptibility as the linear response to an external flavor field. By requiring self-consistency, this approach leads to the usual dispersion relation for growing modes, but differs from the traditional treatment in that it predicts Landau damping of subluminal collective modes. The new dispersion relation has definite analyticity properties and can be expanded for small growth rates. This approach simplifies and intuitively explains Morinaga's proof of sufficiency for the occurrence of growing modes. We show that weakly growing modes arise as soon as an angular crossing is formed, due to their resonant interaction with individual neutrino modes. For longitudinal plasma waves, a similar resonance causes Landau damping or conversely, the two-stream instability.

   hep-phastro-ph.HEJHEP(2024)·46 citations
2. 02*

   Pseudoscalar and vector tetraquarks $bb\overline{c}\overline{c}$

   S. S. Agaev🇦🇿 · K. Azizi🇮🇷 · H. Sundu🇹🇷

   The pseudoscalar and vector four-quark states $bb\overline{c}\overline{c}$ are studied in the context of the QCD sum rule method. We model $T_{\mathrm{PS}}$ and $T_{\mathrm{V}}$ as structures built of diquarks $b^{T}C{\gamma }_{5}b$, $\overline{c}C{\overline{c}}^T$ and $b^{T}C{\gamma }_{5}b$ , $\overline{c}C{\gamma }_{\mu }{\gamma }_5{\overline{c}}^T$, respectively, with $C$ being the charge conjugation matrix. The spectroscopic parameters of the tetraquarks $T_{\mathrm{PS}}$ and $T_{\mathrm{V}}$, i.e., their masses and current couplings are calculated using QCD two-point sum rule method. We evaluate the full widths of $T_{\mathrm{PS}}$ and $T_{\mathrm{V}}$ by taking into account their kinematically allowed decay channels. In the case of the pseudoscalar particle they are processes $T_{\mathrm{PS}}\to B_c^{-}{B}_c^{\ast -}$, $B_c^{-}{B}_c^{-}(1^3{P}_0)$ and $B_c^{\ast -}{B}_c^{-}(1^1{P}_1)$. The vector state $T_{\mathrm{V}}$ can dissociate to meson pairs $2B_c^{-}$, $2B_c^{\ast -}$ and $B_c^{-}{B}_c^{-}(1^1{P}_1)$. Partial widths of these decays are determined by the strong couplings at relevant tetraquark-meson-meson vertices, which evaluated in the context of the three-point sum rule approach. Predictions obtained for the mass and full width of the pseudoscalar $m=(13.092\pm 0.095)\mathrm{GeV}$, ${\Gamma }_{\mathrm{PS}}=(63.7\pm 13.0)\mathrm{MeV}$ and vector $\tilde{m}=(13.15\pm 0.10)\mathrm{GeV}$, ${\Gamma }_{\mathrm{V}}=(53.5\pm 10.3)\mathrm{MeV}$ tetraquarks can be useful for analyses of different four-quark resonances.

   hep-phhep-exhep-latEPJA(2025)·4 citations
3. 03*

   Modified Coulomb potential and the S-state wavefunction of heavy quarkonia

   Shwe Sin Oo🇺🇸 · Sungwook Lee🇺🇸 · Khin Maung Maung🇺🇸

   The combination of relativistic kinematics together with Coulomb or Yukawa potentials is a common place in atomic, nuclear and meson mass phenomenology. In meson spectroscopy, linear and Coulomb-like potentials are the most commonly used potentials and decays rates are also calculated using the value of the wavefunction at the origin. But, it has been known for sometime that the use of relativistic kinematics together with Coulomb or Coulomb-like potentials produces wavefunction singularity at the origin for S-wave \cite{DuranFriarPolyzou}. Therefore, there is a need to address this problem somehow. In this letter, we show how to overcome this problem without destroying the phenomenological success of the use of relativistic kinematics in meson mass spectroscopy. Our method can be easily implemented for similar problems in atomic, nuclear and particle phenomenology.

   hep-ph2 citations
4. 04*

   Unambiguous detection of high energy vortex states via the superkick effect

   Zhengjiang Li🇨🇳 · Shiyu Liu🇨🇳 · Bei Liu🇨🇳 · Liangliang Ji🇨🇳 · Igor P. Ivanov🇨🇳

   Vortex states of photons, electrons, and other particles are freely propagating wave packets with helicoidal wave fronts winding around the axis of a phase vortex. A particle prepared in a vortex state carries a non-zero orbital angular momentum projection on the propagation direction, a quantum number that has never been exploited in experimental particle and nuclear physics. Low-energy vortex photons, electrons, neutrons, and helium atoms have been demonstrated in experiment and found numerous applications, and there exist proposals of boosting them to higher energies. However, verification that a high energy particle is indeed in a vortex state will be a major challenge, since the low energy techniques become impractical at higher energies. Here, we propose a new diagnostic method based of the so-called superkick effect, which can unambiguously detect the presence of a phase vortex. A proof-of-principle experiment with vortex electrons can be done with existing technology, and its realization will also constitute the first observation of the superkick effect.

   hep-phquant-phPRL(2024)·16 citations
5. 05*

   Exploring flavour space of an economical SU(5) GUT in future proton decay measurements

   Gao-Xiang Fang🇨🇳 · Ye-Ling Zhou🇨🇳

   We discuss the potential of future proton decay experiments on the exploration of the flavour space of grand unification. We focus on an economical $SU(5)$ grand unified model (GUT) with the fermion sector extended by including only one copy of 24-plet. Neutrino masses are generated via type-(I+III) seesaw mechanism with the lightest neutrino massless. Gauge unification requires masses of fermions in the 24-plet to be hierarchical, in particular, the electroweak singlet and triplet heavy leptons to be around the canonical seesaw scale and TeV scale, respectively. We address how extra parameters in the flavour space which cannot be touched in flavour measurements can be tested by a multi-channel analysis in future proton decay measurements.

   hep-phPRD(2024)·2 citations
6. 06*

   On Lepton and Baryon Numbers as Local Gauge Symmetries

   Pavel Fileviez Perez🇺🇸

   A simple theory where the total lepton number is a local gauge symmetry is proposed. In this context, the gauge anomalies are cancelled with the minimal number of extra fermionic fields and one predicts that the neutrinos are Majorana fermions. The properties of the neutrino sector are discussed showing that this theory predicts a $3+2$ light neutrino sector. We show that using the same fermionic fields one can gauge the baryon number and define a simple theory where the lepton and baryon numbers can be spontaneously broken at the low scale in agreement with experiments.

   hep-phhep-exhep-thPRD(2024)·10 citations
7. 07*

   Spectrum of the molecular hexaquarks

   Bo Wang🇨🇳 · Kan Chen🇨🇳 · Lu Meng🇩🇪 · Shi-Lin Zhu🇨🇳

   We investigate the mass spectra of molecular-type hexaquark states in the dibaryon systems. These systems are composed of the charmed baryons $[{\Sigma }_c^{(\ast )}$, ${\Xi }_c^{(\prime ,\ast )}]$, doubly charmed baryons $[{\Xi }_{cc}^{(\ast )}]$, and hyperons $[{\Sigma }^{(\ast )}$, ${\Xi }^{(\ast )}]$. We consider all possible combinations of particle-particle and particle-antiparticle pairs, including the S-wave spin multiplets in each combination. We establish the underlying connections among the molecular tetraquarks, pentaquarks, and hexaquarks with the effective quark-level interactions. We find that the existence of molecular states in $D{D}^{\ast }$, $D{\bar{D}}^{\ast }$, and ${\Sigma }_c{\bar{D}}^{(\ast )}$ systems leads to the emergence of a large number of deuteron-like hexaquarks in the heavy flavor sectors. Currently, there have been several experimental candidates for molecular tetraquarks and pentaquarks. The experimental search for near-threshold hexaquarks will further advance the establishment of the underlying dynamical picture of hadronic molecules and deepen our understanding of the role of spin-flavor symmetry in near-threshold residual strong interactions.

   hep-phhep-exPRD(2024)·13 citations
8. 08*

   Strong decays of the isovector-scalar $D^{\ast }{\bar{D}}^{\ast }$ hadronic molecule

   Jin-Cheng Deng🇨🇳 · Bo Wang🇨🇳

   We adopt the effective Lagrangian approach to study the strong decays of the $1^{-}(0^{++})$ $D^{\ast }{\bar{D}}^{\ast }$ molecular state [denoted as $T_{\psi 0}^a(4010)$ according to the LHCb naming convention] through triangle diagrams. The decay channels include the open-charm $D\bar{D}$, and the hidden-charm ${\eta }_c\pi$, $J/\psi \rho$, and ${\chi }_{c1}\pi$. The coupling between the $T_{\psi 0}^a(4010)$ and its constituents $D^{\ast }{\bar{D}}^{\ast }$ is obtained by solving for the residue of the scattering $T$-matrix at the pole. Our calculations yield a total width of few tens MeV for the $T_{\psi 0}^a(4010)$ state using three different form factors, with its main decay channels being ${\eta }_c\pi$ and ${\chi }_{c1}\pi$. The $X(4100)$ and $X(4050)$ have similar masses and widths, with both masses being close to the $D^{\ast }{\bar{D}}^{\ast }$ threshold. Additionally, their decay final states are consistent with those of the $T_{\psi 0}^a(4010)$. Therefore, it is likely that they represent the same state and both potentially correspond to the $T_{\psi 0}^a(4010)$. We suggest that future experiments focus on searching for the $T_{\psi 0}^a(4010)$ signal in the final states ${\eta }_c{\pi }^{-}$, ${\chi }_{c1}{\pi }^{-}$ and $D^0{D}^{-}$ of the $B^0\to {\eta }_c{\pi }^{-}{K}^{+}$, ${\chi }_{c1}{\pi }^{-}{K}^{+}$ and $D^0{D}^{-}{K}^{+}$ processes, respectively, as well as further investigating its resonance parameters with Flatté-like formula.

   hep-phhep-exPRD(2024)·3 citations
9. 09*

   Constraining $\nu$SMEFT coefficients: the case of the extra $\text{U}(1{)}^{\prime }$

   Pietro Colangelo🇮🇹 · Fulvia De Fazio🇮🇹 · Francesco Loparco🇮🇹 · Nicola Losacco🇮🇹

   We study the constraints on low-energy coefficients of the $\nu$SMEFT generalization of the Standard Model effective theory in the simple case of a $\text{U}(1{)}^{\prime }$ enlargement of the Standard Model gauge group. In particular, we analyse the constraints imposed by the requirement that the extended theory remains free of gauge anomalies. We present the cases of explicit realisations, showing the obtained correlations among the coefficients of $d=6$ operators.

   hep-phhep-exhep-latPRD(2024)·4 citations
10. 10*

    Contributions of QED diagrams with vacuum polarization insertions to the lepton anomaly within the Mellin--Barnes representation

    O.P. Solovtsova🇷🇺 · V.I. Lashkevich🇧🇾 · L.P. Kaptari🇷🇺

    We investigate the radiative QED corrections to the lepton ($L=e,\mu$ and $\tau$) anomalous magnetic moment arising from vacuum polarization diagrams by four closed lepton loops. The method is based on the consecutive application of dispersion relations for the polarization operator and the Mellin--Barnes transform for the propagators of massive particles. This allows one to obtain, for the first time, exact analytical expressions for the radiative corrections to the anomalous magnetic moments of leptons from diagrams with insertions of four identical lepton loops all of the same type $\ell$ different from the external one, $L$. The result is expressed in terms of the mass ratio $r=m_{\ell }/m_L$. We investigate the behaviour of the exact analytical expressions at $r\to 0$ and $r\to \infty$ and compare with the corresponding asymptotic expansions known in the literature.

    hep-phhep-thPhys.Part.Nucl.(2024)·0 citations
11. 11*

    Probing Mirror Neutrons and Dark Matter through Cold Neutron Interferometry

    Antonio Capolupo🇮🇹 · Gabriele Pisacane🇮🇹 · Aniello Quaranta🇮🇹 · Francesco Romeo🇮🇹

    We propose a novel neutron interferometry setup to explore the potential existence of mirror neutrons, a candidate for dark matter. Our work demonstrates that if mirror neutrons exist, neutrons will acquire an observable geometric phase due to mixing with these mirror counterparts. This geometric phase, detectable through our interferometric setup, could serve as a direct probe for the presence of mirror matter particles. Additionally, this investigation could shed light on unresolved issues in particle physics, such as the neutron lifetime puzzle. We discuss the setup's versatility and limitations, showing its capability to explore a wide range of parameters in neutron interferometry and potentially uncover new physics.

    hep-phPhys.Dark Univ.(2024)·11 citations
12. 12*

    Multimessenger constraints for electrophilic feebly interacting particles from supernovae

    Pedro De la Torre Luque🇪🇸 · Shyam Balaji🇫🇷 · Pierluca Carenza🇸🇪

    Several extensions of the Standard Model predict the existence of sub-GeV particles that can be copiously produced in the cores of supernovae. A broad family of these particles are dubbed feebly interacting particles (FIPs), which can have masses of up to a few hundreds of MeV. Here, we review the most recent and leading constraints on electrophilic FIPs, describing multimessenger techniques that allow us to probe the full phenomenology of the electron/positron emission produced by these FIPs; from their associated X-ray emission to the production of the $511$~keV line. Furthermore, the approach described here is independent of the specific particle model and can be translated to the coupling and other properties of a variety of different particles, such as axion-like particles, sterile neutrinos or dark photons

    hep-phastro-ph.COastro-ph.HE0 citations
13. 13*

    The magic of entangled top quarks

    Chris D. White🇬🇧 · Martin J. White🇦🇺

    Recent years have seen an increasing body of work examining how quantum entanglement can be measured at high energy particle physics experiments, thereby complementing traditional table-top experiments. This raises the question of whether more concepts from quantum computation can be examined at colliders, and we here consider the property of magic, which distinguishes those quantum states which have a genuine computational advantage over classical states. We examine top anti-top pair production at the LHC, showing that nature chooses to produce magic tops, where the amount of magic varies with the kinematics of the final state. We compare results for individual partonic channels and at proton-level, showing that averaging over final states typically increases magic. This is in contrast to entanglement measures, such as the concurrence, which typically decrease. Our results create new links between the quantum information and particle physics literatures, providing practical insights for further study.

    hep-phhep-exhep-thquant-phPRD(2024)·83 citations
14. 14*

    Calculating the two-photon exchange contribution to $K_L\to {\mu }^{+}{\mu }^{-}$ decay

    En-Hung Chao🇺🇸 · Norman Christ🇺🇸

    We present a theoretical framework within which both the real and imaginary parts of the complex, two-photon exchange amplitude contributing to $K_L\to {\mu }^{+}{\mu }^{-}$ decay can be calculated using lattice QCD. The real part of this two-photon amplitude is of approximately the same size as that coming from a second-order weak strangeness-changing neutral-current process. Thus a test of the standard model prediction for this second-order weak process depends on an accurate result of this two-photon amplitude. A limiting factor of our proposed method comes from low-energy three-particle $\pi \pi \gamma$ states. The contribution from these states will be significantly distorted by the finite volume of our calculation -- a distortion for which there is no available correction. However, a simple estimate of the contribution of these three-particle states suggests their contribution to be at most a few percent allowing their neglect in a lattice calculation with a 10% target accuracy.

    hep-phhep-latPRD(2024)·13 citations
15. 15*

    Neutrino magnetic dipole portal with low energy neutrino nucleus scattering data

    Ying-Ying Li🇨🇳 · Yu-Feng Li🇨🇳 · Shuo-Yu Xia🇨🇳

    Sterile neutrinos that couple to the Standard Model via the neutrino magnetic dipole portals have been extensively studied at various experiments. In this work, we scrutinize these interactions for sterile neutrinos in the mass range of $\text{unit}[0.1]-\text{unit}[50]MeV$ through the nuclear and electron recoils at various neutrino scattering experiments. For the $e$-flavor specific dipole portal, we demonstrate that Dresden-II can provide leading constraints for $m_N\lesssim \text{unit}[0.5]MeV$, setting aside currently unresolved theoretical uncertainties. For the $\mu$-flavor case, we show that the COHERENT experiment can probe a unique parameter region for $m_N$ in the range of $\text{unit}[10]-\text{unit}[40]MeV$ with the full dataset collected by the CsI[Na] scintillation detector, including both the energy and timing structure of the neutrino beam. We also present limits on the parameter regions of the $\tau$-flavor dipole portal using measurements of the solar neutrino flux from dark matter direct detection experiments.

    hep-phhep-exPRD(2026)·7 citations
16. 16*

    Spread Complexity of High Energy Neutrino Propagation over Astrophysical Distances

    Khushboo Dixit🇿🇦 · S. Shajidul Haque🇿🇦 · Soebur Razzaque🇿🇦

    Spread complexity measures the minimized spread of quantum states over all choices of basis. It generalizes Krylov operator complexity to quantum states under continuous Hamiltonian evolution. In this paper, we study spread complexity in the context of high-energy astrophysical neutrinos and propose a new flavor ratio based on complexity. Our findings indicate that our proposal might favor an initial ratio of fluxes as ${\varphi }_{{\nu }_e}^0:{\varphi }_{{\nu }_{\mu }}^0:{\varphi }_{{\nu }_{\tau }}^0=1:0:0$ over a more generally expected ratio of $1:2:0$, when the IceCube neutrino observatory achieves its projected sensitivity to discriminate between flavors. Additionally, complexity-based definitions of flavor ratios exhibit a slight but nonzero sensitivity to the neutrino mass ordering, which traditional flavor ratios cannot capture.

    hep-phastro-ph.HEquant-phInt.J.Theor.Phys.(2025)·2 citations
17. 17*

    $(J/\psi ,J/\psi )$, and $({\eta }_c,{\eta }_c)$ production through two intermediate photons in electron-positron annihilation at B-factories

    Shashank Bhatnagar🇮🇳 · Hluf Negash🇪🇹

    We study the processes, $e^{-}{e}^{+}\to {\gamma }^{\ast }{\gamma }^{\ast }\to J/\psi +J/\psi$, and $e^{-}{e}^{+}\to {\gamma }^{\ast }{\gamma }^{\ast }\to {\eta }_c+{\eta }_c$ at $\sqrt{s}=10.6$ GeV in the framework of $4\times 4$ Bethe-Salpeter equation. For $J/\psi +J/\psi$ production, the dominant contribution is through fragmentation process, while for ${\eta }_c+{\eta }_c$ production, the quark rearrangement diagrams contribute. Our results of cross section for $J/\psi +J/\psi$ and $\psi (2S)+\psi (2S)$ are compatible with the experimental upper limits set by Belle Collaboration, while in the absence of experimental data for ${\eta }_c(1S)+{\eta }_c(1S)$, and ${\eta }_c(2S)+{\eta }_c(2S)$ production, we have given theoretical prediction of their cross sections, and compared with NRQCD prediction.

    hep-phNPA(2025)·8 citations
18. 18*

    Jet quenching in the glasma phase: medium-induced radiation

    João Barata🇺🇸 · Sigtryggur Hauksson🇫🇷 · Xoán Mayo López🇪🇸 · Andrey V. Sadofyev🇵🇹

    Inspired by the recent considerations of parton momentum broadening in the glasma phase, we study the medium-induced soft gluon radiation of jet partons at early times in heavy-ion collisions. The glasma state is assumed to be comprised of independent color domains with homogenous longitudinal fields that vary event by event, and we further complete this model with an event-averaging procedure accounting for the finite correlation length. Using this description, we evaluate the rate of medium-induced radiation from an energetic parton at midrapidity in the glasma phase. We mainly focus on SU(2) color fields for simplicity, also referring to the U(1) case and comparing with the BDMPS-Z rate to gain further insight. Our results show that there is an intricate interplay of the synchrotron-like radiation in a single color domain with the destructive interference between different color domains, after the medium averaging is performed. Thus, we find that the emission rate is sensitive to the matter structure, decreasing for a glasma state populated by smaller color domains, i.e. for a glasma with a larger characteristic saturation scale. Our approach can be applied to more realistic backgrounds, and sets the stage for the modelling of jet evolution in the early stages of heavy-ion collisions.

    hep-phnucl-thPRD(2024)·36 citations
19. 19*

    Primordial Black Holes from First-Order Phase Transition in the xSM

    Dorival Gonçalves🇺🇸 · Ajay Kaladharan🇺🇸 · Yongcheng Wu🇨🇳

    Supercooled first-order phase transition (FOPT) can lead to the formation of primordial black holes (PBHs). This scenario imposes stringent requirements on the profile of the effective potential. In this work, we use the singlet extended Standard Model (xSM) as a benchmark model to investigate this possibility at the electroweak scale. The PBHs formed during a supercooled FOPT have a narrow mass distribution around the mass of Earth. This distribution is closely tied to the temperature at which the PBHs form, corresponding to the FOPT at the electroweak scale. This scenario can be probed with microlensing experiments, space-based gravitational wave detectors, and collider experiments. Remarkably, the future space-based gravitational wave detector LISA will hold the potential to either confirm this PBH scenario in the xSM or completely rule it out for extremely small total dark matter fraction made of PBHs, down to $f_{\mathrm{PBH}}>10^{-300}$. Interestingly, our findings suggest that PBHs within the xSM framework may align with observations of the six ultrashort timescale events reported by the OGLE microlensing experiment.

    hep-phastro-ph.COastro-ph.HEPRD(2025)·37 citations
20. 20*

    Universal properties of the evolution of the Universe in modified loop quantum cosmology

    Jamal Saeed · Rui Pan · Christian Brown · Gerald Clevear · Anzhong Wang

    In this paper, we systematically study the evolution of the Universe in the framework of a modified loop quantum cosmological model (mLQC-I) with various inflationary potentials, including chaotic, Starobinsky, generalized Starobinsky, polynomials of the first and second kinds, generalized T- models and natural inflation. In all these models, the big bang singularity is replaced by a quantum bounce, and the evolution of the Universe both before and after the bounce is universal and weakly depends on the inflationary potentials, as long as the evolution is dominated by the kinetic energy of the inflaton at the bounce. In particular, the evolution in the pre-bounce region can be universally divided into three different phases: pre-bouncing, pre-transition, and pre-de Sitter. The pre-bouncing phase occurs immediately before the quantum bounce, during which the evolution of the Universe is dominated by the kinetic energy of the inflaton. Thus, the equation of state of the inflaton is about one, w = 1. Soon, the inflation potential takes over, so w rapidly falls from one to negative one. This pre-transition phase is very short and quickly turns into the pre-de Sitter phase, whereby the effective cosmological constant with a Planck size takes over and dominates the rest of the contracting phase. In the entire pre-bounce regime, the evolution of the expansion factor and the inflaton can be approximated by analytical solutions, which are universal and independent of the inflation potentials.

    ↳ gr-qcastro-ph.COhep-phhep-thUniverse(2024)·12 citations
21. 21*

    Using gauge invariance to symmetrize the energy-momentum tensor of electrodynamics

    Helmut Haberzettl🇺🇸

    It is shown that using Noether's Theorem explicitly employing gauge invariance for variations of the electromagnetic four-potential $A^{\mu }$ straightforwardly ensures that the resulting electromagnetic energy-momentum tensor is symmetric. The Belinfante symmetrization procedure is not necessary. The method is based on Bessel-Hagen's 1921 clarification of Noether's original procedure, suggesting that the symmetry problem arises from an incomplete implementation of Noether's Theorem. The derivation addresses in some detail where the usual application of Noether's Theorem falls short, what the Belinfante procedure actually does to fix the problem, and why the usual unsymmetric canonical energy-momentum tensor can only be used for extracting four-momentum conservation based on translational invariance, but will provide meaningless results when applied to rotations or boosts, unless modified appropriately.

    ↳ physics.class-phgr-qchep-ph3 citations
22. 22*

    Cosmological Stasis from Dynamical Scalars: Tracking Solutions and the Possibility of a Stasis-Induced Inflation

    Keith R. Dienes🇺🇸 · Lucien Heurtier🇬🇧 · Fei Huang🇮🇱 · Tim M.P. Tait🇺🇸 · Brooks Thomas🇺🇸

    It has recently been realized that many theories of physics beyond the Standard Model give rise to cosmological histories exhibiting extended epochs of cosmological stasis. During such epochs, the abundances of different energy components such as matter, radiation, and vacuum energy each remain fixed despite cosmological expansion. In previous analyses of the stasis phenomenon, these different energy components were modeled as fluids with fixed, unchanging equations of state. In this paper, by contrast, we consider more realistic systems involving dynamical scalars which pass through underdamping transitions as the universe expands. Indeed, such systems might be highly relevant for BSM scenarios involving higher-dimensional bulk moduli and inflatons. Remarkably, we find that stasis emerges even in such situations, despite the appearance of time-varying equations of state. Moreover, this stasis includes several new features which might have important phenomenological implications and applications. For example, in the presence of an additional "background" energy component, we find that the scalars evolve into a "tracking" stasis in which the stasis equation of state automatically tracks that of the background. This phenomenon exists even if the background has only a small initial abundance. We also discuss the intriguing possibility that our results might form the basis of a new "Stasis Inflation" scenario in which no ad-hoc inflaton potential is needed and in which there is no graceful-exit problem. Within such a scenario, the number of e-folds of cosmological expansion produced is directly related to the hierarchies between physical BSM mass scales. Moreover, non-zero matter and radiation abundances can be sustained throughout the inflationary epoch.

    ↳ astro-ph.COhep-phhep-thPRD(2024)·17 citations
23. 23*

    Lorentz-violating extension of Wigner function formalism and chiral kinetic theory

    Ömer F. Dayi🇹🇷

    The quantum kinetic equation for the gauge-invariant Wigner function, constructed from spinor fields that obey the Dirac equation modified by CPT and Lorentz symmetry-violating terms, is presented. The equations for the components of the Wigner function in the Clifford algebra basis are accomplished. Focusing on the massless case, an extended semiclassical chiral kinetic theory in the presence of external electromagnetic fields is developed. We calculate the chiral currents and establish the anomalous magnetic and separation effects in a Lorentz-violating background. The chiral anomaly within the context of extended quantum electrodynamics is elucidated. Finally, we derive the semiclassical Lorentz-violating extended chiral transport equation.

    ↳ hep-thhep-phPRD(2024)·0 citations
24. 24*

    Constraints on Lorentz invariance violation from the extraordinary Mrk 421 flare of 2014 using a novel analysis method

    MAGIC Collaboration: S. Abe (1) · J. Abhir (2) · A. Abhishek (3) · V. A. Acciari (4) · A. Aguasca-Cabot (5) · I. Agudo (6) · T. Aniello (7) · S. Ansoldi (8,43) · L. A. Antonelli (7) · A. Arbet Engels (9) · C. Arcaro (10) · M. Artero (4) and 205 other authors

    The Lorentz Invariance Violation (LIV), a proposed consequence of certain quantum gravity (QG) scenarios, could instigate an energy-dependent group velocity for ultra-relativistic particles. This energy dependence, although suppressed by the massive QG energy scale $E_{\mathrm{QG}}$, expected to be on the level of the Planck energy $1.22\times 10^{19}$ GeV, is potentially detectable in astrophysical observations. In this scenario, the cosmological distances traversed by photons act as an amplifier for this effect. By leveraging the observation of a remarkable flare from the blazar Mrk\,421, recorded at energies above 100 GeV by the MAGIC telescopes on the night of April 25 to 26, 2014, we look for time delays scaling linearly and quadratically with the photon energies. Using for the first time in LIV studies a binned-likelihood approach we set constraints on the QG energy scale. For the linear scenario, we set $95\%$ lower limits $E_{\mathrm{QG}}>2.7\times 10^{17}$ GeV for the subluminal case and $E_{\mathrm{QG}}>3.6\times 10^{17}$ GeV for the superluminal case. For the quadratic scenario, the $95\%$ lower limits for the subluminal and superluminal cases are $E_{\mathrm{QG}}>2.6\times 10^{10}$ GeV and $E_{\mathrm{QG}}>2.5\times 10^{10}$ GeV, respectively.

    ↳ astro-ph.HEhep-phJCAP(2024)·9 citations
25. 25*

    Comprehensive Study of $k$-essence Model: Dynamical System Analysis and Observational Constraints from Latest Type Ia Supernova and BAO Observations

    Saddam Hussain🇮🇳 · Sarath Nelleri🇮🇳 · Kaushik Bhattacharya🇮🇳

    We constrain the parameters of the $k$-essence scalar field model with inverse square and exponential potentials using data sets including Pantheon+SHOES and the Dark Energy Survey (DES) of Type Ia supernovae, Baryon Acoustic Oscillation (BAO) data from SDSS and DESI surveys, and direct measurements of the Hubble parameter and redshift obtained from the differential age method (CC). We also provide a brief perspective on the dynamical evolution of both models and derive stability constraints on the model parameters, which are then used to set appropriate priors. We adopt a Bayesian inference procedure to estimate the model parameters that best fit the data. A comprehensive analysis in light of observational data shows that the $k$-essence model fits well across all data combinations. However, according to the BIC criterion, the $\Lambda$CDM model provides a slightly better fit compared to the $k$-essence model.

    ↳ astro-ph.COgr-qchep-phphysics.data-anJCAP(2025)·20 citations
26. 26*

    Coupled-channel $J^{--}$ meson resonances from lattice QCD

    Jozef J. Dudek🇺🇸 · Christopher T. Johnson🇺🇸

    We extend an earlier calculation within lattice QCD of excited light meson resonances with $J^{PC}=1^{--},2^{--},3^{--}$ at the SU(3) flavor point in the singlet representation, by considering the octet representation. In this case the resonances appear in coupled-channel amplitudes, which we determine, establishing the relative strength of pseudoscalar-pseudoscalar to pseudoscalar-vector decays. Combining the new octet results with the prior results for the singlet, we perform a plausible extrapolation to the physical quark mass, and compare to experimental ${\rho }_J^{\star },K_J^{\star },{\omega }_J^{\star }$ and ${\varphi }_J^{\star }$ resonances.

    ↳ hep-lathep-phPRD(2024)·6 citations
27. 27*

    Helium-4 gravitational form factors: exchange currents

    Fangcheng He🇺🇸 · Ismail Zahed🇺🇸

    We evaluate the leading exchange corrections to the Helium-4 gravitational form factors (GFFs) upto momenta of the order of the nucleon mass. We use both the K-harmonic method with simple pair nucleon potential, and a Jastrow trial function using the Argonne $v_{14}$ potential, to evaluate the Helium-4 GFFs. The exchange current contributions include the pair interaction, plus the seagull and the pion exchange interactions, modulo the recoil corrections. To estimate the off-shellness of the pion nucleon coupling in this momenta range, we discuss the results using either the pseudo-scalar (PS) or pseudo-vector (PV) pion-nucleon couplings. When the PV coupling is used, the pair diagram contribution is higher order in the non relativistic expansion. The results for the Helium-4 A-GFF are comparable to those given by the impulse approximation, especially for the PS coupling using both the K-Harmonic method and variational method. The exchange current contributions with the PS coupling for the charge form factor of Helium-4, yield better agreement with the existing data over a broad range of momenta, especially when the Argonne $v_{14}$ potential including the D-wave admixture is used.

    ↳ nucl-thhep-phPRC(2024)·3 citations
28. 28*

    Holographic and Gravity-Thermodynamic Approaches in Entropic Cosmology: Bayesian Assessment using late-time Data

    Udit K. Tyagi🇮🇳 · Sandeep Haridasu🇮🇹 · Soumen Basak🇮🇳

    We investigate the cosmological implications of entropy-based approaches in the context of Holographic Dark Energy (HDE) and Gravity-Thermodynamics (GT) formalisms. We utilise the extended Barrow entropy form, with the index parameter $\Delta$, representing the fractal dimension of the horizon. We also test implementing different parameter ranges for $\Delta$, which can be extended to Tsallis' interpretation within the same formal cosmology. We perform a Bayesian analysis to constrain the cosmological parameters using the Pantheon+, more recent DESy5, DESI, and, as a supplement, Quasar datasets. We find that the HDE model within almost all data combinations performs extremely well in comparison to the GT approach, which is usually strongly disfavored. Using the combination of DESy5+DESI alone, we find that the GT approaches are disfavored at $|\log \mathcal{B}|\sim 5.8$ and $|\log \mathcal{B}|\sim 6.2$ for the Barrow and Tsallis limits on $\Delta$, respectively, wrt $\Lambda$CDM model. While the HDE approach is statistically equivalent to $\Lambda$CDM when comparing the Bayesian evidence. We also investigate the evolution of the dark energy equation of state and place limits on the same, consistent with quintessence-like behaviour in the HDE approaches.

    ↳ astro-ph.COgr-qchep-phPRD(2024)·26 citations
29. 29*

    Prospects for the detection of Dark Matter with Long-lived Mediators in the Sun using the Southern Wide-field Gamma-ray Observatory

    Micael Andrade🇧🇷 · Juan Fagiani🇧🇷 · Clarissa Siqueira🇧🇷 · Vitor de Souza🇧🇷 · Aion Viana🇧🇷

    The operation of the next generation of gamma-ray observatories will lead to a great advance in dark matter searches. In this paper, we use the hidden sectors hypothesis within the so-called secluded models to calculate the capabilities of the Southern Wide-field Gamma-ray Observatory (SWGO) to detect gamma-ray signatures produced by dark matter particles concentrated in the Sun. We assume the dark matter particle annihilates into metastable mediators which decay into $\gamma \gamma$, $e^{+}{e}^{-}$, ${\tau }^{+}{\tau }^{-}$, and $\bar{b}b$ outside the Sun. We found that the SWGO will be able to probe a spin-dependent cross-section of about $10^{-46}$ cm${}^2$ for dark matter masses smaller than 5 TeV. This result shows an unprecedented sensitivity surpassing the current instruments by more than one order of magnitude.

    ↳ astro-ph.HEhep-phJCAP(2025)·5 citations
30. 30*

    Model-Independent Test of Prerecombination New Physics: Measuring the Sound Horizon with Gravitational Wave Standard Sirens and the Baryon Acoustic Oscillation Angular Scale

    William Giarè🇬🇧 · Jonathan Betts🇬🇧 · Carsten van de Bruck🇬🇧 · Eleonora Di Valentino🇬🇧

    In a broad class of cosmological models where spacetime is described by a pseudo-Riemannian manifold, photons propagate along null geodesics, and their number is conserved, upcoming Gravitational Wave (GW) observations can be combined with measurements of the Baryon Acoustic Oscillation (BAO) angular scale to provide model-independent estimates of the sound horizon at the baryon-drag epoch. By focusing on the accuracy expected from forthcoming surveys such as LISA GW standard sirens and DESI or Euclid angular BAO measurements, we forecast a relative precision of ${\sigma }_{r_{\mathrm{d}}}/r_{\mathrm{d}}\sim 1.5\%$ within the redshift range $z\lesssim 1$. This approach will offer a unique model-independent measure of a fundamental scale characterizing the early universe, which is competitive with model-dependent values inferred within specific theoretical frameworks. These measurements can serve as a consistency test for $\Lambda$CDM, potentially clarifying the nature of the Hubble tension and confirming or ruling out new physics prior to recombination with a statistical significance of $\sim 4\sigma$.

    ↳ astro-ph.COhep-phPRL(2025)·30 citations
31. 31*

    Cosmological constraints on ${\Lambda }_{\mathrm{s}}$CDM scenario in a type II minimally modified gravity

    Özgür Akarsu🇹🇷 · Antonio De Felice🇯🇵 · Eleonora Di Valentino🇬🇧 · Suresh Kumar🇮🇳 · Rafael C. Nunes🇧🇷 · Emre Özülker🇹🇷 · J. Alberto Vazquez🇲🇽 · Anita Yadav🇮🇳

    The idea of a rapid sign-switching cosmological constant (mirror AdS-dS transition) in the late universe at $z\sim 1.7$, known as the ${\Lambda }_{\mathrm{s}}$CDM model, has significantly improved the fit to observational data and provides a promising scenario for alleviating major cosmological tensions, such as the $H_0$ and $S_8$ tensions. However, in the absence of a fully predictive model, implementing this fit required conjecturing that the dynamics of the linear perturbations are governed by general relativity. Recent work embedding the ${\Lambda }_{\mathrm{s}}$CDM model with the Lagrangian of a type II minimally modified gravity known as VCDM has propelled ${\Lambda }_{\mathrm{s}}$CDM to a fully predictive model, removing the uncertainty related to the aforementioned assumption; we call this new model ${\Lambda }_{\mathrm{s}}$VCDM. In this work, we demonstrate that not only does ${\Lambda }_{\mathrm{s}}$CDM fit the data better than the standard $\Lambda$CDM model, but the new model, ${\Lambda }_{\mathrm{s}}$VCDM, performs even better in alleviating cosmological tensions while also providing a better fit to the data, including CMB, BAO, SNe Ia, and cosmic shear measurements. Our findings highlight the ${\Lambda }_{\mathrm{s}}$CDM framework, particularly the ${\Lambda }_{\mathrm{s}}$VCDM model, as a compelling alternative to the standard $\Lambda$CDM model, especially by successfully alleviating the $H_0$ tension. Additionally, these models predict higher values for ${\sigma }_8$, indicating enhanced structuring, albeit with lower present-day matter density parameter values and consequently reduced $S_8$ values, alleviating the $S_8$ tension as well. This demonstrates that the data are well fit by a combination of background and linear perturbations, both having dynamics differing from those of $\Lambda$CDM. This paves the way for further exploration of new ways for embedding the sign-switching cosmological constant into other models.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2024)·65 citations
32. 32*

    Interpreting DESI 2024 BAO: late-time dynamical dark energy or a local effect?

    Ioannis D. Gialamas🇪🇪 · Gert Hütsi🇪🇪 · Kristjan Kannike🇪🇪 · Antonio Racioppi🇪🇪 · Martti Raidal🇪🇪 · Martin Vasar🇪🇪 · Hardi Veermäe🇪🇪

    We perform fits to DESI, CMB and supernova data to understand the physical origin of the DESI hint for dynamical dark energy. We find that the linear parametrization of the equation of state $w$ may guide to misleading interpretations, such as the hint for a phantom Universe, which are not preferred by the data. Instead, physical quintessence models fit the data well. Model-independently, present observations prefer deviations from the constant dark energy, $w=-1$, only at very low redshifts, $z<\mathcal{O}(0.1)$. We find that this result is driven by low-$z$ supernova data. Therefore, either the fundamental properties of our Universe, characterised by the equation of state $w$ and the Hubble parameter $H$, underwent dramatic changes very recently or, alternatively, we do not fully understand the systematics of our local Universe in a radius of about $300h^{-1}\mathrm{Mpc}$.

    ↳ astro-ph.COhep-phPRD(2025)·190 citations
33. 33*

    Revisiting the $\mathcal{N}=1$ supersymmetric trinification models from intersecting D6-branes

    Adeel Mansha🇨🇳 · Tianjun Li🇨🇳 · Mudassar Sabir🇨🇳

    We revisit the construction of the $\mathcal{N}=1$ supersymmetric trinification models with gauge group $\mathrm{U}(3{)}_C\times \mathrm{U}(3{)}_L\times \mathrm{U}(3{)}_R$ in Type IIA string theory on ${\mathbf{T}}^6/({\mathbb{Z}}_2\times {\mathbb{Z}}_2)$ orientifold with intersecting D6-branes. The non-trivial K-theory conditions and tadpole cancellation conditions severely restrict the number of allowed models even for the case of rectangular two-tori. Using a supervised search algorithm, we find a few four-family models where the highest wrapping number is 2. For these models, we present the complete particle spectra and the gauge coupling relations at the string-scale.

    ↳ hep-thhep-phCommun.Theor.Phys.(2024)·6 citations
34. 34*

    String loops and gravitational positivity bounds: imprint of light particles at high energies

    Simon Caron-Huot🇨🇦 · Junsei Tokuda🇰🇷

    We study loop corrections to positivity bounds on effective field theories in the context of $2\to 2$ scattering in gravitational theories, in the presence of light particles. It has been observed that certain negative contributions at low energies are enhanced by inverse powers of a small mass $m$ and are nontrivial to cancel against other low-energy contributions. These originate from near the forward limit of diagrams involving graviton exchange. We observe that scattering in this kinematics domain remains infrared-sensitive even at high center-of-mass energy. By considering a string-inspired model in which high-energy loops can be calculated using unitarity and Regge behavior of tree amplitudes, we uncover a natural mechanism through which $1/m$-enhanced terms perfectly cancel between low and high energy contributions. This concretely explains possible positivity violations in the presence of gravity from the high-energy viewpoint.

    ↳ hep-thhep-phJHEP(2024)·31 citations
35. 35*

    Regularizing infrared divergences in de Sitter spacetime: Loops, dimensional regularization, and cutoffs

    Javier Huenupi🇨🇱 · Ellie Hughes🇨🇱 · Gonzalo A. Palma🇨🇱 · Spyros Sypsas🇹🇭

    Correlation functions of light scalar fields in de Sitter spacetime, computed via standard perturbation theory, often exhibit secular growth characterized by time-dependent divergent terms in the form of powers of $\ln a(t)$, where $a(t)$ is the scale factor describing cosmic expansion. It is widely believed that loop corrections further enhance this secular growth. We argue that this is not necessarily the case: Loop corrections can be systematically handled using standard perturbative techniques, such as dimensional regularization, without introducing new $\ln a(t)$ terms. We focus on a canonical massless scalar field $\phi$ with self-interactions described by a potential $\mathcal{V}(\phi )$, and analyze correlation functions represented by diagrams with a single vertex and an arbitrary number of loops. In this framework, infrared divergences can be systematically eliminated with counterterms at each order in perturbation theory, leading to loop-corrected correlation functions that are indistinguishable from their tree-level forms, with no secular growth from loops. Furthermore, adopting a Wilsonian perspective, we explore the role of cutoffs in computing loop corrections within effective field theory and identify the effective potential ${\mathcal{V}}_{\mathrm{eff}}(\phi )$, which guarantees cutoff-independent observables. We conclude that when infrared comoving cutoffs are used to regularize loop integrals, time-dependent Wilsonian coefficients are necessary to maintain cutoff-free correlation functions. Neglecting this time dependence results in secular growth from loops.

    ↳ hep-thastro-ph.COhep-phPRD(2024)·20 citations
36. 36*

    Chiral Separation Effect from Holographic QCD

    Domingo Gallegos🇲🇽 · Matti Järvinen🇰🇷 · Eamonn Weitz🇫🇷

    We analyze the chiral separation effect (CSE) in QCD by using the gauge/gravity duality. In QCD, this effect arises from a combination of chiral anomalies and the axial $U(1)$ anomaly. Due to the axial gluon anomaly, the value of the CSE conductivity is not determined by the anomalies of QCD but receives radiative corrections, which leads to nontrivial dependence on temperature and density. To analyze this dependence, we use different variants of V-QCD, a complex holographic model, carefully fitted to QCD data. We find our results for the anomalous CSE conductivity at small chemical potential and nonzero temperature to be in good qualitative agreement with recent results from lattice QCD simulations. We furthermore give predictions for the behavior of the conductivity at finite (vectorial and axial) chemical potentials.

    ↳ hep-thhep-lathep-phJHEP(2024)·7 citations
37. 37*

    Dark Spiky Primordial Black Holes

    Aurora Ireland🇺🇸

    Recent observations of two nearby black hole low-mass X-ray binaries have suggested possible indication of dark matter density spikes. While the evidence is compelling, one issue with this interpretation is that light black holes formed from stellar collapse are not expected to form dark matter spikes, and so it is unclear how the stellar-mass black holes in these binaries could have acquired such features. Since primordial black holes are expected to form ultra-dense dark matter mini-spikes, in this article we explore the possibility of a primordial origin for these light black holes.

    ↳ astro-ph.COgr-qchep-phPRD(2025)·18 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.