HEP Phenomenology·hep-ph

Wed·Nov 26, 2025Wednesday·November 26, 2025

30 papers—20 primary·10 cross-listed·reconstructed*

01*
An NLO-Matched Initial and Final State Parton Shower on a GPU
Michael H. Seymour🇬🇧 · Siddharth Sule🇬🇧
Recent developments have demonstrated the potential for high simulation speeds and reduced energy consumption by porting Monte Carlo Event Generators to GPUs. We release version 2 of the CUDA C++ parton shower event generator GAPS, which can simulate initial and final state emissions on a GPU and is capable of hard-process matching. As before, we accompany the generator with a near-identical C++ generator to run simulations on single-core and multi-core CPUs. Using these programs, we simulate NLO Z production at the LHC and demonstrate that the speed and energy consumption of an NVIDIA V100 GPU are on par with a 96-core cluster composed of two Intel Xeon Gold 5220R Processors, providing a potential alternative to cluster computing.
hep-phSciPost Phys.Codeb.(2026)·3 citations
02*
Hard exclusive photoproduction of photon-meson pairs: pseudoscalar channels $π$ , $η$ and $η^{'}$
Nikola Crnković🇭🇷 · Goran Duplančić🇭🇷 · Saad Nabeebaccus🇬🇧 · Kornelija Passek-K.🇭🇷 · Bernard Pire🇫🇷 · Lech Szymanowski🇵🇱 · Samuel Wallon🇫🇷
We investigate the hard exclusive photoproduction of photon-meson pairs at leading-twist and leading-order in perturbative QCD, and focus on pseudoscalar mesons $M \in {π^{\pm}, π^{0}, η, η^{'}}$ . Compact analytical expressions are obtained for the amplitudes involving quark generalized parton distributions, with the two-gluon components of the $η$ and $η^{'}$ distribution amplitudes included. The numerical analysis is performed in the moderate- $ξ$ region, where valence-quark GPDs are expected to be important. In this region, we find a strong impact of the pion-pole term in $γ π^{\pm}$ production, and a non-negligible effect for neutral mesons. We also observe a marked dependence of $γ η^{'}$ photoproduction on two-gluon contributions. This process offers enhanced sensitivity to the shape of the GPDs already at leading-order, while the tested dependence on the meson distribution amplitude and the renormalization scale introduces further theoretical uncertainties, the latter emphasizing the need for next-to-leading-order corrections. Our results provide a concise analytical framework and a numerical baseline for future studies.
hep-phhep-exPRD(2026)·4 citations
03*
Strangelet Searches from Neutron Stars, Binary Mergers, and Gamma-Ray Bursts with Current and Future Observatories
C.R. Das🇷🇺
Strange quark matter (SQM) is considered a possible true ground state of QCD at high densities. This idea motivates research on exotic compact objects and certain cosmic-ray phenomena. For instance, the remnant HESS J1731-347 contains a low-mass neutron star, about $0.7 7_{- 0.17}^{+ 0.20}$ $M_{⊙}$ and $10. 4_{- 0.78}^{+ 0.86}$ km in radius, making it a strong candidate for a strange quark star. Other events, such as GW170817 and GRB 250702B, provide conditions that may favor the formation of strangelets. Strangelets are stable clusters of SQM, potentially created during the phase transition between the 2SC and CFL color-superconducting states. These clusters could generate monochromatic $γ$ -ray lines in very-high-energy spectra through self-annihilation. This work analyzes the stability of strangelets, production cross-sections, and mass-to-charge ratios using QCD-based models. Data from H.E.S.S., Fermi-LAT, MAGIC-II, and CTA were used to set limits on spectral features and possible fluxes. Detecting narrow $γ$ -ray lines will require improved instrument sensitivity. By integrating evidence from multimessenger astrophysics and dense QCD simulations, this study investigates the equations of state for compact stars and explores the potential cosmological influence of SQM.
hep-phastro-ph.HEastro-ph.IM0 citations
04*
New constraints on axion with gamma-ray observations of the Crab Nebula
Kazunori Kohri🇯🇵 · Haruki Takahashi🇯🇵
In this paper, we derive the upper bounds on the coupling of axion-like particles (ALPs) with photon as a function of the mass by considering axion-photon conversion in the Crab Nebula. Previous studies have not considered the influence of the magnetic field within the Crab Nebula. The magnetic field plays a crucial role through the Synchrotron Self-Compton (SSC) process, in which high-energy electrons produce synchrotron radiation that is subsequently up-scattered by the same electrons via inverse Compton scattering to generate gamma rays. Therefore, neglecting the magnetic field in modeling leads to theoretical inconsistencies. In this work, we investigate the significance of the magnetic field effect and demonstrate that even differences in magnetic field modeling can substantially alter the conversion probability. We thus, for the first time, point out that proper consideration of the magnetic field is essential in ALP searches using gamma rays from the Crab Nebula. The resulting constraints reach up to a coupling of $g_{aγ γ} ≲ 1 \times 1 0^{- 11} GeV^{- 1}$ for ALP masses in the range $1 0^{- 10} eV ≲ m_{a} ≲ 1 0^{- 6} eV$ .
hep-phastro-ph.COastro-ph.HEPRD(2026)·0 citations
05*
Phenomenological analysis of charmless $B \to P V$ decays in the modified perturbative QCD approach
Sheng Lü🇨🇳 · Ru-Xuan Wang🇨🇳 · Mao-Zhi Yang🇨🇳
We analyze the charmless two-body decays of the $B$ meson into a pseudoscalar and a vector meson, referred to as $B \to P V$ decay, within the framework of the modified perturbative QCD (PQCD) approach, which was originally developed to solve the long-standing puzzles, the so-called $π π$ and $π K$ puzzles. In this method, based on the conventional PQCD calculations, soft form factors and contributions arising from color-octet quark-antiquark components in the final state are introduced, which involve essentially nonperturbative dynamics. By employing the flavor SU(3) symmetry and its breaking effect, the parameters describing soft contributions are correlated and subsequently reduced into a more concise set of SU(3) parameters. Through a $χ^{2}$ analysis procedure applied to the experimental data, these parameters are determined, from which the corresponding theoretical results for the branching ratios and $C P$ asymmetries in $B \to P V$ decays are derived. Within this framework, it is demonstrated that the theoretical calculations align well with experimental measurements, suggesting that the method developed for solving $π π$ and $π K$ puzzles can be extended to more decay modes of the $B$ meson. The numerical analysis shows that these soft contributions have a significant influence on the theoretical results. Furthermore, more precise experimental data are needed for deeper investigations of the $C P$ asymmetries.
hep-phPRD(2026)·0 citations
06*
HyperFORM -- a FORM package for parametric integration with hyperlogarithms
Adam Kardos🇭🇺 · Sven-Olaf Moch🇩🇪 · Oliver Schnetz🇩🇪
We present an implementation of algorithms for the symbolic integration of hyperlogarithms multiplied by rational functions in the computer algebra system FORM. This implementation encompasses cases where hyperlogarithms have rational letters or a rational argument. It complements the previous implementation, HyperInt, in MAPLE by Erik Panzer, utilizing the advantages of FORM in the efficient handling of large symbolic expressions. Among a wide range of applications, this approach enables the computation of many Feynman integrals.
hep-phhep-thmath-phmath.MPEPJC(2026)·9 citations
07*
Multiplicity dependence of quarkonia production at ultra high energies
E. Levin (Tel Aviv University.)🇮🇱
In this paper we propose an approach in high energy QCD, which allows us to calculate the inclusive quarkonia production at ultra high energies. This approach is based on $t$ -channel unitarity and on the expressions for dipole densities from the procedure of summing of large Pomeron loops which we have developed in our previous papers. In the framework of this approach we discuss the dependence of quarkonia production on the multiplicity of the accompanying hadrons. In this paper we used the three gluons fusion mechanism for quarkonia production, without assuming the multiplicity dependence of the saturation scale. We found the multiplicity distribution of produced gluon with ( $P_{n}^{J /Ψ}$ ) and without ( $P_{n}^{g l u o n}$ ) the quarkonia production. It turns out that $\frac{P _{n}^{J /Ψ}}{P _{n}^{g l u o n}} \propto n^{2}$ as has been expected and discussed in corresponding publications.
hep-phPRD(2026)·0 citations
08*
Is the large uncertainty of $δ_{C P}$ fundamentally encoded in the neutrino quantum state?
Michela Ignoti🇮🇹 · Claudia Frugiuele🇮🇹 · Matteo G. A. Paris🇮🇹 · Marco G. Genoni🇮🇹
The precise measurement of the leptonic CP-violating phase $δ_{C P}$ remains one of the major open challenges in neutrino physics, as current experiments achieve only very limited accuracy. We address this issue through the lens of quantum estimation theory. A distinctive feature of neutrino oscillation experiments is that they cannot freely optimize the probe or measurement, since both are constrained by the production and detection of flavor eigenstates. We therefore examine whether the large uncertainty in $δ_{C P}$ originates from intrinsic reasons, either of the neutrino quantum state or of flavor measurements, or if it instead stems from experimental limitations. By comparing quantum and classical Fisher information, we demonstrate that the limited sensitivity to $δ_{C P}$ originates primarily from the information content of flavor measurements. Furthermore, we show that targeting the second oscillation maximum, as in the ESS $ν$ SB proposal, substantially enhances $δ_{C P}$ information compared to experiments centered on the first maximum.
hep-phhep-exquant-ph14 citations
09*
First determination of fragmentation functions in an exotic-hadron candidate
S. Kumano🇨🇳
In recent years, there are experimental reports on exotic-hadron candidates, which have different quark configurations from ordinary $q q ˉ$ and $q q q$ constituents. However, it is not easy to confirm their exotic nature from global observables such as masses, spins, parities, and decay widths. At high energies, internal quark and gluon configurations could become more apparent because hadrons should be described by fundamental degrees of freedom of quarks and gluons in quantum chromodynamics. One of such possibilities is to use the fragmentation functions (FFs). In this work, accurate FFs of an exotic hadron candidate $f_{0}$ (980) are determined for the first time by an global analysis of experimental data on $e^{+} + e^{-} \to f_{0} (980) + X$ with recent precise measurements of the Belle collaboration. From the global analysis, we found that their second moments have a relation $M_{u} = M_{d} ≪ M_{s} \sim M_{g}$ for up-quark, down-quark, strange-quark, and gluon FFs. Furthermore, the function $D_{s}^{f_{0}} (z)$ is distributed in the larger- $z$ region in comparison with the functions $D_{u}^{f_{0}} (z)$ , $D_{d}^{f_{0}} (z)$ , and $D_{g}^{f_{0}} (z)$ . These facts support that the $f_{0} (980)$ has the $s s ˉ$ configuration at high energies. This is a new finding that $f_{0} (980)$ should be considered mainly as the $s s ˉ$ state, which is different from our usual understanding as a tetraquark (or $K K ˉ$ ) hadron from low-energy studies. Our results could indicate the transition of the internal configuration picture that $f_{0} (980)$ looks like a $q q ˉ$ state at high energies although it is described by tetra-quark or $K K ˉ$ molecule state at low energies. It sheds light on a new direction in exotic hadron physics.
hep-phhep-exhep-latnucl-ex+10 citations
10*
Revisiting lepton flavor violation: $τ$ and meson decays
Kevin A. Urquía-Calderón🇩🇰 · Oleg Ruchayskiy🇩🇰
The minimal type-I seesaw model provides a simple explanation of neutrino flavor oscillations and induces charged lepton flavor violation (cLFV). Despite extensive previous studies, semileptonic cLFV channels remain underexplored. Using updated form factors, decay constants, and oscillation data, we revisit $τ$ and meson decay channels, performing a systematic comparison across the seesaw parameter space. Surprisingly, we find that decays such as $τ \to ℓ ρ$ can dominate over purely leptonic $τ$ -sector probes, including $τ \to 3 ℓ$ and even $τ \to ℓ γ$ , in certain regions. In contrast, heavy-meson decays remain far below experimental sensitivity. Considering global constraints on the seesaw parameters, we derive branching ratios for the relevant cLFV processes and identify those within potential reach of next-generation experiments.
hep-phJHEP(2026)·2 citations
11*
Towards the two-loop electroweak corrections to the Drell-Yan process: the infrared structure
Tommaso Armadillo🇧🇪 · Simone Devoto🇧🇪 · Michele Dradi🇮🇹 · Alessandro Vicini🇮🇹
We discuss the lepton-pair production process in Quantum Electrodynamics. We present the ultraviolet-renormalised and infrared-subtracted finite contribution of the second-order virtual corrections to the inclusive lepton-pair production cross section $u u ˉ \to e^{+} e^{-}$ . The results are obtained within a new computational framework, OCEANN, developed in view of the evaluation of the exact two-loop electroweak virtual corrections to high-energy scattering processes. One of the key methodological features in this approach is the representation of the scattering amplitude with arbitrary precision at every stage of the calculation. The analysis in QED allows us to address the treatment of the infrared structure of the process and it can be easily extended to the complete electroweak Standard Model case. The perfect agreement with the literature, for this subset of corrections, provides a non trivial validation of the general framework.
hep-phJHEP(2026)·7 citations
12*
New framework for extracting GPDs from exclusive photon electroproduction
Jian-Wei Qiu🇺🇸 · Nobuo Sato🇺🇸 · Zhite Yu🇺🇸
Recently, a new framework for studying generic $2 \to 3$ hard exclusive reactions, referred to as single-diffractive hard exclusive processes, has been introduced to provide a cleaner separation of the underlying physical mechanisms. In this work, we expand this formalism to the case of exclusive real-photon electroproduction off a nucleon, $e (ℓ) + N (p) \to e (ℓ^{'}) + N (p^{'}) + γ (q^{'})$ , which represents the classical channel for accessing generalized parton distributions (GPDs) in nucleons and nuclei. This extension enables a more systematic and physically transparent formulation of the reaction dynamics, paving the way for improved extractions of GPDs from experimental data as compared to existing approaches.
hep-phhep-exhep-latnucl-ex+1PRD(2026)·0 citations
13*
$B^{+} \to K^{+} ν ν ˉ$ Excess and DM semi-annihilation
Jongkuk Kim🇰🇷 · Pyungwon Ko🇰🇷
In 2023, Belle II collaboration announced the observarion of the $B^{+} \to K^{+} ν ν ˉ$ decay channel for the first time. This decay channel provides a clean signal with high precision in theoretical calculation. However, we encounter $2.8 σ$ deviation from the Standard Model (SM) prediction. To resolve this excess, we study scalar dark matter (DM) model with local discrete $Z_{3}$ symmetry. Assuming dark $U (1)_{X} \equiv U (1)_{L_{μ} - L_{τ}}$ symmetry, this $U (1)_{L_{μ} - L_{τ}}$ symmetry is spontaneously broken into local discrete $Z_{3}$ by non-zero vacuum expectation value of dark Higgs boson. Considering dark Higgs mass is $2$ GeV, we can explain the recent $Br (B^{+} \to K^{+} ν ν ˉ)$ excess reported from Belle II collaboration and relic abundance at the same time.
hep-phPRD(2026)·6 citations
14*
Chiral phonons in metal-organic frameworks as quantum sensors for the direct detection of dark matter
Marek Matas🇨🇿 · Filip Krizek🇫🇮 · Carl P. Romao🇨🇿
We investigate a new quantum sensor for dark matter direct detection with sub-eV sensitivity, focusing on several candidate materials that potentially host chiral phonons with large magnetic moments that can be directly read out with an external magnetometer. We focus on metal-organic frameworks (MOFs) as possible candidate materials for single chiral phonon detection due to their noncentrosymmetric structure, tunability, and the ability to host these excitations in stable acoustic bands. We identify several promising candidates and compare their projected dark matter detection sensitivity for all possible interactions identified within effective field theory. We establish that the expected sensitivity does not depend heavily on the specific choice of the MOF, enabling us to tailor the final material composition to facilitate the magnetic readout. We then propose a prototype setup able to test the direct readout of a chiral phonon sensor with a surface-integrated magnetometer.
hep-phastro-ph.COcond-mat.supr-con1 citation
15*
Impact of quark flavor violating SUSY on h(125) decays at future lepton colliders
H. Eberl (1)🇦🇹 · K. Hidaka (2)🇯🇵 · E. Ginina (1) ((1) HEPHY, Vienna, (2) Tokyo Gakugei U.)🇦🇹
We study the CP-even neutral Higgs boson decays $h^{0} \to c c ˉ, b b ˉ, b s ˉ, γ γ, g g$ in the Minimal Supersymmetric Standard Model (MSSM) with general quark flavor violation (QFV) due to squark generation mixings, identifying the $h^{0}$ as the Higgs boson with a mass of 125 GeV. We compute the widths of the $h^{0}$ decays to $c c ˉ, b b ˉ, b s ˉ$ at full one-loop level. For the $h^{0}$ decays to $γ γ$ and $g g$ we compute the widths at NLO QCD level. {\it For the first time}, we perform a systematic MSSM parameter scan for these widths respecting all the relevant theoretical and experimental constraints, such as those from B-meson data, and the 125 GeV Higgs boson data from recent LHC experiments, as well as the limits on Supersymmetric (SUSY) particle (sparticle) masses from the LHC experiments. We also take into account the expected sparticle mass limits from the future HL-LHC experiment in our analysis. {\it In strong contrast to} the usual studies in the MSSM with Minimal Flavor Violation (MFV), we find that the deviations of these MSSM decay widths from the Standard Model (SM) values can be quite sizable and that there are significant correlations among these deviations. All of these sizable deviations in the $h^{0}$ decays are mainly due to large scharm-stop mixing and large sstrange-sbottom mixing. Such sizable deviations from the SM can be observed at high signal significance in future lepton colliders such as ILC, CLIC, CEPC, FCC-ee and muon collider {\it even after} the failure of SUSY particle discovery at the HL-LHC. In case the deviation pattern shown here is really observed at the lepton colliders, then it would strongly suggest the discovery of QFV SUSY (the MSSM with general QFV).
hep-phhep-exPRD(2026)·0 citations
16*
NNLO QCD predictions for $W γ γ$ production at the LHC
Paolo Garbarino🇨🇭 · Massimiliano Grazzini🇨🇭 · Stefan Kallweit🇨🇭 · Chiara Savoini🇩🇪
Triboson production processes play a crucial role in probing the electroweak sector of the Standard Model, as they involve quartic gauge-boson couplings already at the tree level. With these measurements entering the precision era at the Large Hadron Collider (LHC), accurate theoretical predictions become indispensable. We present the computation of the next-to-next-to-leading-order (NNLO) QCD radiative corrections to the production of a $W$ boson in association with two photons ( $W γ γ$ ) at the LHC. The calculation is exact, except for the finite part of the two-loop contribution, which is included in the leading-colour approximation. Predictions for the fiducial cross section and selected kinematic distributions are provided at a centre-of-mass energy of $s = 13$ TeV, under standard experimental selection cuts. In line with observations for other multiboson processes involving direct photons, we find sizable NNLO corrections that enhance the next-to-leading-order predictions by about $23%$ , with residual perturbative uncertainties that can be roughly estimated to be at the $5%$ level.
hep-phhep-exEPJC(2026)·4 citations
17*
CP Violation in Charmed Meson Decays into Final States with $η^{'}$
Carolina Bolognani🇳🇱 · Ulrich Nierste🇩🇪 · Stefan Schacht🇬🇧 · K. Keri Vos🇳🇱
We derive Standard Model predictions for the CP asymmetries of singly-Cabibbo suppressed $D \to P η^{'}$ decays, where $P = K, π, η$ . Our predictions are based on the approximate SU(3) $_{F}$ symmetry of QCD and include first-order symmetry-breaking effects in a systematic way. The underlying symmetry leads to correlations between different decay modes. To this end we predict the correlations between $a_{CP}^{dir} (D^{+} \to π^{+} η^{'})$ and $a_{CP}^{dir} (D_{s}^{+} \to K^{+} η^{'})$ as well as $a_{CP}^{dir} (D^{0} \to π^{0} η^{'})$ and $a_{CP}^{dir} (D^{0} \to η η^{'})$ . Our results can be used to probe the Standard Model with future measurements by LHCb, Belle II and BESIII. At the same time, such future measurements permit the extraction of the key theory parameter related to the ratio of color-suppressed to color-favoured contributions to the decay amplitudes. Future data on both branching ratios and CP asymmetries will automatically improve our predictions and thereby also their sensitivity to physics beyond the Standard Model.
hep-phhep-exJHEP(2026)·0 citations
18*
A simple generalization of the low-energy theorem for the effective Higgs-gluon-gluon coupling for the case of simultaneous decoupling of several heavy quarks
Konstantin G. Chetyrkin🇷🇺
We extend in an extremely simple and straightforward way the well-known low-energy theorem for an effective Higgs-like scalar-gluon-gluon coupling [1] (as well as a similar one for for the effective coupling of the Higgs-like field to the light scalar quark currents) in QCD including arbitrary number of heavy quarks in addition to the light ones. The application of the generalized low-energy theorem allows the extraction of the four-loop effective Higgs-gluon-gluon coupling valid for extensions of the Standard Model with additional heavy quarks from the 3-loop results of [2] for the decoupling constant of $α_{s}$ .
hep-phJHEP(2026)·1 citation
19*
Mechanical properties of the proton from a deformed AdS holographic model
Ayrton Nascimento🇧🇷 · Henrique Boschi-Filho🇧🇷
We study the gravitational form factors of the proton and some of its mechanical properties. We use a holographic model based on the AdS/CFT correspondence, in which a deformation in the anti-de Sitter background geometry is considered. By describing the proton as a Dirac field in this background, we numerically evaluate the gloun contribution of its gravitational form factors $A$ and $C$ from its energy-momentum tensor. A comparison of our numerical results with respect to some lattice QCD results and previous results in holography is made. In general, a good agreement is found. We also evaluate the term $D$ and make use of it to compute the pressure and shear distributions in the system, which result in a stable composed particle interpretation consistent with the von Laue stability condition. The energy distribution in the system is also obtained. Internal forces are investigated to support this picture. We are also able to compute the radii associated with these distributions in the proton.
hep-phhep-thPRD(2026)·4 citations
20*
The Intrinsic Dimension of Collider Events and Model-Independent Searches in 100 Dimensions
Raffaele Tito D'Agnolo🇫🇷 · Alfredo Glioti🇮🇹 · Gabriele Rigo🇫🇷 · Alessandro Valenti🇨🇭
The phase space of hadron collider events spans hundreds of dimensions, generating an intricate geometry that we are just starting to explore. The number of possible new physics signals is exponential in the number of dimensions and detecting all of them is currently impossible for any human or artificial intelligence. In this work we introduce a method to search for new physics model-independently in this high-dimensional space. It is based on the measurement of the most basic property of the manifold of collider events, its dimensionality. Our proposed technique does not suffer from a look-elsewhere effect that grows exponentially with the number of dimensions of the dataset, and by construction is insensitive to energy scale uncertainties. We illustrate its potential by finding new physics in simulated events with hundreds of phase space dimensions, taking as input single particles rather than jets. This study sets the stage for new model-independent search strategies based on global properties of collider data manifolds.
hep-phhep-exphysics.data-anPRD(2026)·3 citations
21*
The Speed of Gravity and the Fate of Dark Energy
Jeremy Sakstein🇺🇸 · Bhuvnesh Jain🇺🇸
On August 17 $^{th}$ 2017, observatories worldwide made a landmark detection: gravitational waves and light from a binary neutron star merger. This event revolutionized our understanding of astrophysics, cosmology, and gravitation. In this proceeding of the 2025 International Congress of Basic Science, we describe how it transformed our view of cosmic acceleration (dark energy). The near-simultaneous arrival of light and gravitational waves shows that their speeds agree to within one part in $1 0^{15}$ , excluding large classes of modified gravity theories and interactions between dark energy and matter.
↳ astro-ph.COastro-ph.HEastro-ph.SRgr-qc+10 citations
22*
Cold Dark Matter and Dark Energy Based on an Analogy with Superconductivity
Guanming Liang🇺🇸
We present a novel candidate for cold dark matter consisting of condensed Cooper pairs in a theory of interacting fermions with broken chiral symmetry. Establishing the thermal history from the early radiation era to the present, the fermions are shown to behave like standard radiation at high temperatures, but then experience a critical era decaying faster than radiation, akin to freeze-out that sets the relic abundance. Through a second-order phase transition, fermion - antifermion pairs condense and the system asymptotes towards zero temperature and pressure. By the present era, the non-relativistic, massive condensate decays slightly faster than in the standard scenario -- a unique prediction that may be tested by combined measurements of the cosmic microwave background and large scale structure. We also show that in the case of massive fermions, the phase transition is frustrated, and freeze-out instead leaves a residual, long-lived
↳ astro-ph.COhep-phPhysRevLett.134.191004, 2025·0 citations
23*
Quintessential Inflation in Light of ACT DR6
Sayantan Choudhury🇮🇳 · Swapnil Kumar Singh🇮🇳 · Satish Kumar Sahoo
We perform a precision investigation of smooth quintessential inflation in which a single canonical scalar field unifies the two known phases of cosmic acceleration. Using a CMB-normalized runaway exponential potential, we obtain sharply predictive inflationary observables: a red-tilted spectrum with $n_{s} = 0.964241$ and an exceptionally suppressed tensor-to-scalar ratio $r = 7.48 \times 1 0^{- 5}$ at $N = 60$ , lying near the optimal region of current Planck+ACT constraints. Remarkably, all observable scales exit the horizon within an extremely narrow field interval $Δ ϕ ≃ 0.03 M_{Pl}$ , tightly linking early and late-time dynamics and reducing theoretical ambiguities. While inflationary tensors remain invisible to CMB B-mode surveys, the subsequent stiff epoch-an intrinsic hallmark of quintessential cosmology-imprints a blue-tilted stochastic gravitational-wave background within the discovery reach of future interferometers such as LISA, DECIGO, ALIA, and BBO. Our results demonstrate that this minimal, featureless model not only survives current bounds, but provides concrete, falsifiable predictions across gravitational-wave frequencies spanning over twenty orders of magnitude.
↳ gr-qcastro-ph.COhep-phhep-th11 citations
24*
A Focused Review of Quintom Cosmology: From Quintom Dark Energy to Quintom Bounce
Tao-tao Qiu🇨🇳 · Yifu Cai🇨🇳 · Yang Liu🇨🇳 · Si-Yu Li🇨🇳 · Jarah Evslin🇨🇳 · Xinmin Zhang🇨🇳
The recently released data of DESI DR2 favors a dynamical dark energy theory, with the equation of state crossing the cosmological constant boundary $w = - 1$ . In this paper, we briefly review quintom cosmology, especially the quintom bounce. We will give three examples of a quintom bounce and one example of a cyclic universe with quintom matter.
↳ astro-ph.COgr-qchep-phhep-thCPC(2026)·8 citations
25*
Anisotropic flows in Au+Au collisions at $s_{NN} = 2.4 GeV$ with a Skyrme pseudopotential
Xin Li🇨🇳 · Si-Pei Wang🇨🇳 · Rui Wang🇮🇹 · Zhen Zhang🇨🇳 · Jie Pu🇨🇳 · Chun-Wang Ma🇨🇳 · Lie-Wen Chen🇨🇳
Within the framework of the lattice Boltzmann-Uehling-Uhlenbeck transport model, we present a systematic study of proton anisotropic flow observables measured by the HADES collaboration, by utilizing the recently developed density-, momentum- and isospin-dependent N $5$ LO Skyrme pseudopotential. In particular, we investigate the impacts of the momentum dependence of nucleon mean-field potentials, the stiffness of symmetric nuclear matter (SNM) EOS, the high-density behaviors of the symmetry energy and the in-medium modification of nucleon-nucleon elastic cross sections on proton $v_{1}$ , $v_{2}$ , $v_{3}$ , and $v_{4}$ in Au+Au collisions at $s_{NN} = 2.4 GeV$ . Our results show that the proton anisotropic flows are strongly sensitive to the momentum dependence of nucleon mean-field potential as well as the incompressibility coefficient $K_{0}$ of SNM. In addition, the transverse momentum dependence of the proton $v_{2}$ exhibits a modest sensitivity to the higher-order skewness coefficient $J_{0}$ and kurtosis coefficient $I_{0}$ of SNM as well as the momentum dependence of the symmetry potential, while the transverse momentum dependence of the proton $v_{1}$ is shown to modestly depend on the in-medium modification of nucleon-nucleon elastic cross sections. Moreover, the high-density symmetry energy seems to have limited effects on the proton anisotropic flows. These findings highlight the necessity of considering the momentum dependence of nucleon mean-field potentials including the symmetry potential, the higher-order characteristic parameters of SNM EOS beyond $K_{0}$ , and the in-medium modification of nucleon-nucleon elastic cross sections, in future Bayesian transport model analyses on proton anisotropic flows in heavy-ion collisions at HADES energies, thereby to extract information on nuclear matter EOS as well as the associated underlying nuclear effective interactions.
↳ nucl-thastro-ph.HEhep-phnucl-exPRC(2026)·1 citation
26*
The effect of sound speed on the gravitational wave spectrum of first order phase transitions in the early universe
Mika Mäki
Gravitational waves from first-order phase transitions are a promising probe of physics beyond the Standard Model, as many extensions of the standard model result in first-order phase transitions in the early universe, from which the resulting gravitational waves could be detectable with the upcoming Laser Interferometer Space Antenna (LISA). The properties of the phase transition and the resulting gravitational wave spectrum are determined by five key parameters: the nucleation temperature $T_{n}$ , phase transition strength at the nucleation temperature $α_{n}$ , bubble wall speed $v_{wall}$ , transition rate $β$ and the sound speed $c_{s}$ . Of these, the sound speed $c_{s}$ is determined by the equation of state $p (T, ϕ)$ . In most studies, the plasma of the early universe has been assumed to be ultrarelativistic and therefore following the bag equation of state with $c_{s} = \frac{1}{3}$ . In this thesis, the PTtools simulation framework for first-order phase transitions, based on the Sound Shell Model, has been extended to include support for arbitrary equations of state and therefore for a temperature- and phase-dependent sound speed $c_{s} (T, ϕ)$ . The thesis also functions as a reference manual for PTtools. The framework has been tested with the constant sound speed model, in which the sound speed is a different constant in each phase. The sound speed has been shown to have a significant effect on the resulting gravitational wave spectrum, especially when changing the sound speed results in a change in the type of the solution. This has laid the groundwork for simulating cosmological phase transitions with realistic equations of state. This will result in in gravitational wave spectra that can be used in the LISA data analysis pipeline to search for the existence and parameters of a first-order phase transition in the early universe.
↳ astro-ph.COhep-ph1 citation
27*
Natural inflation in Palatini $F (R)$
N. Bostan🇹🇷 · R.H. Dejrah🇹🇷 · C. Dioguardi🇪🇪 · A. Racioppi🇪🇪
$F (R)$ Palatini gravity provides a robust framework for constructing viable inflationary potentials. In this study, we examine natural inflation and show that its consistency with observational data can be restored when the model is embedded within $F (R)$ Palatini gravity, specifically for $F (R) = R + α R^{n}$ with $7/4 ≲ n \leq 2$ . For completeness, we also demonstrate that models with $n > 2$ do not yield comparable improvements, achieving partial agreement with the data only in the limit $n \to 2$ .
↳ gr-qcastro-ph.COhep-phJCAP(2026)·5 citations
28*
Locality constraints in AdS $_{2}$ without parity
Manuel Loparco🇨🇭 · Grégoire Mathys🇨🇭 · João Penedones🇨🇭 · Jiaxin Qiao🇨🇭 · Xiang Zhao🇨🇭
We study bulk locality constraints in quantum field theories in AdS $_{2}$ . The known derivation of locality sum rules in AdS $_{d + 1}$ does not apply for $d = 1$ due to the different singularity structure of the conformal blocks and the inequivalence of operator orderings on the boundary. Assuming unitarity and a mild growth condition, we establish power-law bounds for correlators, derive dispersion relations and an expansion in terms of ``even'' and ``odd'' local blocks that converges in the entire AdS $_{2}$ . These yield two novel families of symmetric and antisymmetric locality sum rules. We test these sum rules explicitly in the free scalar field theory.
↳ hep-thhep-phJHEP(2026)·5 citations
29*
Reanalyzing DESI DR1: 2. Constraints on Dark Energy, Spatial Curvature, and Neutrino Masses
Anton Chudaykin🇨🇭 · Mikhail M. Ivanov🇺🇸 · Oliver H. E. Philcox🇺🇸
We carry out an independent re-analysis of the Dark Energy Spectroscopic Instrument (DESI) public dataset, focusing on extensions to the standard cosmological model, $Λ$ CDM. Utilizing the dataset and Effective Field Theory (EFT)-based pipeline described in Paper 1, we constrain cosmological models with massive neutrinos ( $Λ$ CDM+ $M_{ν}$ ), spatial curvature ( $o Λ$ CDM), dynamical dark energy ( $w_{0} w_{a}$ CDM), and their combinations using the power spectrum and bispectrum of DESI galaxies and quasars. Our work also presents the first measurements of relevant non-minimal cosmological parameters from the combination of cosmic microwave background (CMB) and DESI full-shape (FS) data, which are made possible thanks to carefully chosen priors on EFT parameters. We find that the addition the FS likelihood to DESI's baryon acoustic oscillation (BAO) data improves the limits on the spatial curvature by a factor of two over the BAO only results, though the improvements are less significant with the CMB data. The dark energy equation of state figure-of-merit increases both with and without the supernovae data (SNe), by $\approx 30%$ and $\approx 20%$ relative to the CMB+BAO and CMB+BAO+SNe results, respectively. Our FS likelihood also yields the strongest CMB-independent constraint on the total neutrino mass $M_{ν} < 0.32 eV$ , with the $30%$ improvement due to the bispectrum. In combination with the CMB, we find a $14%$ improvement assuming the $Λ$ CDM+ $M_{ν}$ model (yielding $M_{ν} < 0.059 eV$ ), but this increases to $22%$ when using non-minimal backgrounds: $M_{ν} < 0.097 eV$ in $o Λ$ CDM+ $M_{ν}$ and $M_{ν} < 0.13 eV$ in $w_{0} w_{a}$ CDM+ $M_{ν}$ . Overall, our work illustrates that robust and substantial gains in constraining power can be obtained by incorporating the FS power spectrum and bispectrum measurements in analyses of non-minimal cosmological models.
↳ astro-ph.COastro-ph.GAgr-qchep-ph+1PRD(2026)·34 citations
30*
Caustic crossings in giant arcs with extended dark matter objects
Djuna Croon🇬🇧 · Benedict Crossey🇬🇧 · Jose Maria Diego🇪🇸 · Bradley J. Kavanagh🇪🇸 · Jose Maria Palencia🇪🇸
Caustic-crossing stars observed in giant arcs behind galaxy clusters provide a powerful probe of dark matter substructure. While previous work has focused on point-like lenses such as primordial black holes, we extend this framework to extended dark objects (EDOs), including ultracompact minihalos formed from the collapse of primordial overdensities. We develop an analytic model of microlensing by EDOs embedded in a macrolensing cluster potential and derive the resulting caustics and light curves. Depending on the EDO size relative to the effective Einstein radius, we show that they may generate additional narrow caustics, leading to novel features in the light curve. Applying our framework to the MACS J1149 LS1 ``Icarus'' event, we constrain EDOs with radii up to $1 0^{7} R_{⊙}$ . Our results demonstrate that caustic-crossing events complement galactic microlensing searches, as they can probe EDOs with larger physical size. We discuss the implications for current and future observations, which promise to deliver a statistical sample of caustic transients and correspondingly sharper constraints on dark objects.
↳ astro-ph.COastro-ph.GAhep-phPRD(2026)·5 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.