Mon·Jul 22, 2024Monday·July 22, 2024

1. 01*

   A model for Axial Non-Standard Interactions of neutrinos with quarks

   S. Abbaslu🇮🇷 · Yasaman Farzan🇮🇷

   The neutrino oscillation experiments are setting increasingly strong upper bounds on the vector Non-Standard neutrino Interactions (NSI) with matter fields. However, the bounds on the axial NSI are more relaxed, raising the hope that studying the neutral current events at an experiment such as DUNE can give a glimpse on new physics. We build a model that gives rise to axial NSI with large couplings leading to observable deviation from the standard prediction at DUNE. The model is based on a $U(1)$ gauge symmetry with a gauge boson of mass $\sim 30$~GeV which can be discovered at the high luminosity LHC. Combining the LHC and DUNE discoveries, we can unravel the axial form of interaction. The cancellation of anomalies of the gauge group suggests new heavy quarks as well as a dark matter candidate. The new quarks mixed with the first generation quarks can also be discovered at the LHC. Moreover, they provide a seesaw mechanism that explains the smallness of the $u$ and $d$ quark masses. The dark matter has an axial coupling to the quarks which makes its discovery via spin dependent direct dark matter search experiments possible.

   hep-phNPB(2025)·8 citations
2. 02*

   Vector Dark Matter from the 5-Dimensional Representation of $SU(2{)}_L$

   Patricio Escalona🇨🇱 · Sebastián Acevedo🇨🇱 · Paulo Areyuna🇨🇱 · Gonzalo Benítez-Irarrázabal🇨🇱 · Pablo Solar🇨🇱 · Alfonso Zerwekh🇨🇱

   The introduction of electroweak multiplets that transform under any representation of the standard $SU(2{)}_L$ gauge group suggests the existence of electrically neutral stable particles capable of serving as cold dark matter in the $\Lambda$CDM cosmological model. This paradigm, known as minimal dark matter, has primarily focused on spin-$0$ and spin-$1/2$ particles. We extend this study to the spin-1 case using the 5-dimensional real representation. We address unitarity concerns arising from the model's interactions with electroweak and Higgs fields of the Standard Model, investigating implications for dark matter relic density, direct and indirect detection, including non-perturbative Sommerfeld enhancement for the latter. Collider signatures of the proposed model are also examined. Our findings suggest that the model remains consistent with experimental constraints, particularly for dark matter masses on the order of dozens of TeV, and could potentially be tested using $\gamma$-ray observatories such as CTA.

   hep-phJHEP(2024)·3 citations
3. 03*

   Domain wall constraints on the doublet left-right symmetric model from pulsar timing array data

   Dhruv Ringe🇮🇳

   Recent evidence of a stochastic gravitational wave (GW) background found by NANOGrav and other pulsar timing array (PTA) collaborations has inspired many studies looking for possible sources. We consider the hypothesis that the GW signature is produced by domain walls (DWs) arising in the doublet left-right symmetric model (DLRSM) due to the spontaneous breaking of the discrete parity symmetry. The DW network consists of two types of DWs, namely $Z_2$ and $LR$ DWs, which have different surface tensions. We find kink solutions for both types of DWs and obtain the parametric dependence of the surface tension. Considering the GW signal from the DLRSM DW model with and without the contribution from supermassive black hole binaries, we perform a Bayesian analysis using the PTA data to estimate the posterior distribution and identify best-fit parameter ranges. The PTA data favors a parity-breaking scale of $\mathcal{O}(10^5)$\,GeV, and a biased potential $V_{\mathrm{bias}}\sim (\mathcal{O}(100)\mathrm{MeV}{)}^4$. The model with only DLRSM DWs is slightly favored over the model where additional SMBHB contribution is considered.

   hep-phPRD(2025)·3 citations
4. 04*

   QCD corrections of $e^{+}{e}^{-}\to J/\psi +c+\bar{c}$ using the principle of maximum conformality

   Xu-Dong Huang🇨🇳 · Xing-Gang Wu🇨🇳 · Xu-Chang Zheng🇨🇳 · Bin Gong🇨🇳 · Jian-Xiong Wang🇨🇳

   In this paper, we compute the total and differential cross sections for $e^{+}{e}^{-}\to J/\psi +c+\bar{c}$ at the $B$ factories up to next-to-leading order (NLO) corrections within the framework of nonrelativistic QCD factorization theory. We then obtain improved pQCD series of those cross sections by using the Principle of Maximum Conformality (PMC). We show that the PMC can be applied for any pQCD calculable observable at the total and differential levels via a self-consistent way in perturbation theory. We observe that a more precise prompt total cross section at the NLO level can be achieved after applying the PMC, e.g. $\sigma {|}_{\mathrm{prompt}}^{\mathrm{PMC}}=0.565_{-0.125}^{+0.144}\text{pb}$. Here the uncertainty is the squared average of those from the ${\alpha }_s$ fixed-point uncertainty $\Delta {\alpha }_s(M_Z)$, the uncertainty of charm quark mass $\Delta m_c$, and an estimated contribution of the uncalculated NNLO-terms as predicted by the Padé approximation approach. The differential cross sections $d\sigma /d{P}_{J/\psi }$, $d\sigma /d|\cos \theta |$, and $d\sigma /dz$ for $e^{+}{e}^{-}\to J/\psi +c+\bar{c}$ are further examined. Those results show that by further considering the feed-down contributions, the PMC predictions show better agreement with the Belle measurements.

   hep-phPRD(2024)·2 citations
5. 05*

   Phenomenological study of the charged particles production in pPb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV

   Kapil Saraswat🇹🇼 · Deependra Singh Rawat🇮🇳 · Akash Pandey🇮🇳 · Venktesh Singh🇮🇳 · H. C. Chandola🇮🇳

   We have studied transverse momentum ($p_{\mathrm{T}}$) spectra of charged hadrons in various pseudo-rapidity ranges for p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV. The medium effects such as collective flow and energy loss resulting from heavy-ion collisions have also been investigated using modified Tsallis distribution function over a wide range of $p_{\mathrm{T}}$ that indicates the transverse collective flow at low and intermediate $p_{\mathrm{T}}$ range and in-medium energy loss in high $p_{\mathrm{T}}$ range.

   hep-ph0 citations
6. 06*

   PineAPPL Grids of Open Heavy-Flavor Production in the GM-VFNS

   Jan Wissmann🇩🇪 · Tomáš Ježo🇩🇪 · Ingo Schienbein🇫🇷 · Hubert Spiesberger🇩🇪 · Michael Klasen🇩🇪

   Many next-to-leading order QCD predictions are available through Monte Carlo (MC) simulations. Usually, multiple CPU hours are needed to calculate predictions at a required precision, which is unfeasible for global PDF analyses. This problem is solved by a process known as gridding: The values of the hard-scattering cross-section are calculated only once with the MC program, and then interpolated and stored in look-up tables (grids) of the kinematical variables. To obtain the physical predictions, they are convolved with the PDFs (e.g. during the fitting stage in a PDF global analysis), which takes a tiny fraction of the time needed to calculate the MC results. This is possible with PineAPPL, a library tackling the aforementioned process of grid creation and convolution. In this work, we use PineAPPL to grid the predictions for open heavy-flavor production in the general-mass variable-flavor-number scheme (GM-VFNS). In the GM-VFNS, the differential cross-section interpolates between the fixed-flavor-number scheme (FFNS) and the zero-mass variable-flavor-number scheme (ZM-VFNS). These are each only valid in different kinematical regions, in which the GM-VFNS cross-section reproduces the FFNS and ZM-VFNS as the limiting cases of high energies and small masses, respectively. Better than permille agreement is achieved between the grids and the MC predictions, while at the same time not substantially increasing the time of the MC calculations.

   hep-phPoS(2025)·1 citation
7. 07*

   Emergent Canonical Spin Tensor in the Chiral-Symmetric Hot QCD

   M. Buzzegoli (Iowa State University and West University of Timisoara)🇺🇸 · A. Palermo (Stony Brook)🇺🇸

   The spin tensor is fundamental to relativistic spin hydrodynamics, but its definition is ambiguous due to the pseudogauge symmetry. We show that this ambiguity can be solved in interacting field theories. We prove that the mean-field limit of a modified Nambu-Jona-Lasinio model with spin-spin interactions is equivalent to nondissipative spin hydrodynamics with a canonical spin tensor.

   hep-phhep-thnucl-thPRL(2024)·25 citations
8. 08*

   Dark matter for Majorana neutrinos in a ${\mathbb{Z}}_4$ symmetry

   Leon M.G. de la Vega🇲🇽 · Patrick J. Fitzpatrick🇲🇽 · Rolando Martinez-Ramirez🇲🇽 · Eduardo Peinado🇲🇽

   In the minimal Scotogenic model with fermionic dark matter, the neutrino Yukawa matrix is fine-tuned to satisfy current bounds on $\mu \to e\gamma$ while producing dark matter through thermal freeze-out. One way to avoid this bound is to open a new annihilation channel for dark matter (DM) with a scalar field that breaks the lepton number spontaneously. This introduces a physical Goldstone boson $a$, which can constitute a light relic and opens up the lepton flavor violating channel $\mu \to ea$. In this work, we introduce a model that contains the new annihilation channel for fermionic dark matter but avoids the introduction of the Goldstone boson by using a discrete ${\mathbb{Z}}_4$ instead of a continuous symmetry. In this way, cosmological constraints on the light relic and experimental limits on lepton flavor violating decays to the Goldstone boson are avoided. We analyze the experimental viability of the model, identifying the region of parameter space where lepton flavor violating constraints are not saturated, DM has the correct relic density, and DM direct detection experiments are sensitive to the DM candidate.

   hep-phPRD(2024)·4 citations
9. 09*

   QCD phase diagram in the $T-eB$ plane for varying pion mass

   Mahammad Sabir Ali🇮🇳 · Chowdhury Aminul Islam🇩🇪 · Rishi Sharma🇮🇳

   We study the effect of a varying pion mass on the quantum chromodynamics (QCD) phase diagram in the presence of an external magnetic field, aiming to understand it, for the first time, using Nambu\textendash Jona-Lasinio like effective models. We compare results from both its local and nonlocal versions. In both cases, we find that the inverse magnetic catalysis (IMC) near the crossover is eliminated with increasing pion mass, while the decreasing trend of crossover temperature with increasing magnetic field persists for pion mass values at least up to $440$ MeV. Thus, the models are capable of capturing qualitatively the results found by lattice QCD (LQCD) for heavy (unphysical) pions. The key feature in the models is the incorporation of the effect of a reduction in the coupling constant with increasing energy. Along with reproducing the IMC effect, it enables models to describe the effects of heavier current quark masses without introducing additional parameters. For the local NJL model, this agreement depends on how the parameters of the model are fit at the physical point. In this respect, the nonlocal version, which, due to its formulation, automatically exhibits the IMC effect around the crossover region, captures the physics more naturally. We further use the nonlocal framework to determine the pion mass beyond which the IMC effect around the transition region does not exist anymore.

   hep-phhep-latnucl-thPRD(2024)·9 citations
10. 10*

    Electroweak Symmetry Restoration in the N2HDM via Domain Walls

    Mohamed Younes Sassi🇩🇪 · Gudrid Moortgat-Pick🇩🇪

    Domain walls are a type of topological defects that can arise in the early universe after the spontaneous breaking of a discrete symmetry. They can form in several beyond the Standard Model theories with an extended Higgs sector such as the Next to-Two-Higgs-Doublet model (N2HDM). In this work, we discuss the domain wall solution related to the singlet scalar of the N2HDM and demonstrate the possibility of restoring the electroweak symmetry inside and in the vicinity of the domain wall. Such symmetry restoration can have profound implications on early universe cosmology as the weak sphaleron rate inside the domain wall would, in principle, be unsuppressed compared to the rate outside the wall. We also discuss the possibility of generating CP-violating vacua localized in the vicinity of the domain wall. Our work is a first step towards the realization of electroweak baryogenesis mediated by domain walls in the N2HDM.

    hep-phJHEP(2025)·13 citations
11. 11*

    Strong CP and Flavor in Multi-Higgs Theories

    Lawrence Hall🇺🇸 · Claudio Andrea Manzari🇺🇸 · Bea Noether🇺🇸

    We introduce a class of multi-Higgs doublet extensions of the Standard Model that solves the strong CP problem with profound consequences for the flavor sector. The Yukawa matrices are constrained to have many zero entries by a "Higgs-Flavor" symmetry, $G_{\mathrm{HF}}$, that acts on Higgs and quark fields. The violation of both CP and $G_{\mathrm{HF}}$ occurs in the Higgs mass matrix so that, for certain choices of $G_{\mathrm{HF}}$ charges, the strong CP parameter $\bar{\theta }$ is zero at tree-level. Radiative corrections to $\bar{\theta }$ are computed in this class of theories. They vanish in realistic two-Higgs doublet models with $G_{\mathrm{HF}}={\mathbb{Z}}_3$. We also construct realistic three-Higgs models with $G_{\mathrm{HF}}=\mathrm{U}(1)$, where the one-loop results for $\bar{\theta }$ are model-dependent. Requiring $\bar{\theta }<10^{-10}$ has important implications for the flavor problem by constraining the Yukawa coupling and Higgs mass matrices. Contributions to $\bar{\theta }$ from higher-dimension operators are computed at 1-loop and can also be sufficiently small, although the hierarchy problem of this class of theories is worse than in the Standard Model.

    hep-phhep-exhep-thPRD(2025)·11 citations
12. 12*

    Momentum shift and on-shell recursion relation for electroweak theory

    Yohei Ema🇺🇸 · Ting Gao🇺🇸 · Wenqi Ke🇺🇸 · Zhen Liu🇺🇸 · Kun-Feng Lyu🇺🇸 · Ishmam Mahbub🇺🇸

    We study the All-Line Transverse (ALT) shift which we developed for on-shell recursion of amplitudes for particles of any mass. We discuss the validity of the shift for general theories of spin $\le$ 1, and illustrate the connection between Ward identity and constructibility for massive spin-1 amplitude under the ALT shift. We apply the shift to the electroweak theory, and various four-point scattering amplitudes among electroweak gauge bosons and fermions are constructed. We show explicitly that the four-point gauge boson contact terms in massive electroweak theory automatically arise after recursive construction, independent of UV completion, and they automatically cancel the terms growing as (energy)${}^4$ at high energy. We explore UV completion of the electroweak theory that cancels the remaining (energy)${}^2$ terms and impose unitarity requirements to constrain additional couplings. The ALT shift framework allows consistent treatment in dealing with contact term ambiguities for renormalizable massive and massless theories, which we show can be useful in studying real-world amplitudes with massive spinors.

    hep-phhep-thPRD(2024)·14 citations
13. 13*

    Scalar Dark Matter Production through the Bubble Expansion Mechanism:The Role of the Lorentz factor and Non-Renormalizable Interactions

    Jose A. R. Cembranos🇪🇸 · Jesús Luque🇪🇸 · Javier Rubio🇪🇸

    We consider a Bubble Expansion mechanism for the production of scalar dark matter during a first-order phase transition in the very early Universe. Seeking for a dark matter energy density in agreement with observations, we study different renormalizable and non-renormalizable interactions between the dark matter species and the field undergoing the transition, considering all possible regimes for the Lorentz boost factor associated with the motion of the bubble wall. By employing a combination of analytical and numerical techniques, we demonstrate that sufficient dark matter production is achievable even in the previously unexplored low-velocity bubble expansion regime, enlarging the parameter space and possibilities of the scenario. Notably, for the non-renormalizable interactions it is found that the produced dark matter abundances exhibit a similar qualitative behavior to the renormalizable case, even for low Lorentz boost factors. Furthermore, for a transition around the electroweak scale, the associated gravitational wave spectrum is within the reach of future detectors.

    hep-phastro-ph.COhep-thEPJC(2025)·5 citations
14. 14*

    Antenna subtraction for final-state radiation at N${}^3$LO

    Petr Jakubčík🇨🇭

    I review some aspects of antenna subtraction at next-to-next-to-leading order (NNLO) in QCD and provide motivation for its extension to N${}^3$LO. Next, I introduce the antenna functions required for the construction of infrared counterterms for final-state radiation at this order. Lastly, I describe the evaluation of the antenna functions and their phase-space integration, first presented in [1-3], and I elaborate on their application to precision observables in jet production at lepton colliders.

    hep-phPoS(2024)·2 citations
15. 15*

    The Non-Relativistic Effective Field Theory Of Dark Matter-Electron Interactions

    Gordan Krnjaic🇺🇸 · Duncan Rocha🇺🇸 · Tanner Trickle🇺🇸

    Electronic excitations in atomic, molecular, and crystal targets are at the forefront of the ongoing search for light, sub-GeV dark matter (DM). In many light DM-electron interactions the energy and momentum deposited is much smaller than the electron mass, motivating a non-relativistic (NR) description of the electron. Thus, for any target, light DM-electron phenomenology relies on understanding the interactions between the DM and electron in the NR limit. In this work we derive the NR effective field theory (EFT) of general DM-electron interactions from a top-down perspective, starting from general high-energy DM-electron interaction Lagrangians. This provides an explicit connection between high-energy theories and their low-energy phenomenology in electron excitation based experiments. Furthermore, we derive Feynman rules for the DM-electron NR EFT, allowing observables to be computed diagrammatically, which can systematically explain the presence of in-medium screening effects in general DM models. We use these Feynman rules to compute absorption, scattering, and dark Thomson scattering rates for a wide variety of high-energy DM models.

    hep-phastro-ph.COJHEP(2025)·14 citations
16. 16*

    Probing the decay $A^0\to h^0{Z}^{(\ast )}$ in Two-Higgs-Doublet Models in the inverted hierarchy scenario at the Large Hadron Collider

    A.G. Akeroyd🇬🇧 · S. Alanazi🇬🇧 · Stefano Moretti🇬🇧

    Searches are being carried out at the Large Hadron Collider (LHC) for the decay of the CP-odd scalar ($A^0$) in Two-Higgs-Doublet Models (2HDMs) with Natural Flavour Conservation (NFC) in the channel $A^0\to h^{0}Z$, where $h^0$ is either the discovered 125 GeV Higgs boson or is an undiscovered CP-even scalar with a mass below 125 GeV. The latter possibility is called the "inverted hierarchy scenario" (IH) and would provide the opportunity of simultaneous discovery of two scalars. In both searches the selection cuts are optimised for the case of an on-shell $Z$ boson. For the case of the $Z$ boson being off-shell (denoted by $Z^{\ast }$, for which $m_{A^0}-m_{h^0}<m_Z$) no limits are set on the relevant 2HDM parameters from this process. It is known that the decay $A^0\to h^0{Z}^{\ast }$ can have a large branching ratio (BR) in 2HDMs (especially in the Type I structure). In the context of the IH scenario and developing our previous work, we calculate the signal cross section $\sigma (gg\to A^0)\times \mathrm{BR}(A^0\to h^0{Z}^{(\ast )})\times \mathrm{BR}(h^0\to b\overline{b},\tau \overline{\tau })$ in the four types of 2HDMs with NFC. We also suggest some selection cuts that could provide sensitivity to $A^0\to h^0{Z}^{\ast }$ in the IH scenario.

    hep-phAdv.High Energy Phys.(2026)·4 citations
17. 17*

    Living at the Edge: A Critical Look at the Cosmological Neutrino Mass Bound

    Daniel Naredo-Tuero🇪🇸 · Miguel Escudero🇨🇭 · Enrique Fernández-Martínez🇪🇸 · Xabier Marcano🇪🇸 · Vivian Poulin🇫🇷

    Cosmological neutrino mass bounds are becoming increasingly stringent. The latest limit within $\Lambda$CDM from Planck 2018+ACT lensing+DESI is $\sum m_{\nu }<0.072\mathrm{eV}$ at 95\% CL, very close to the minimum possible sum of neutrino masses ($\sum m_{\nu }>0.06\mathrm{eV}$), hinting at vanishing or even ``negative'' cosmological neutrino masses. In this context, it is urgent to carefully evaluate the origin of these cosmological constraints. In this paper, we investigate the robustness of these results in three ways: i) we check the role of potential anomalies in Planck CMB and DESI BAO data; ii) we compare the results for frequentist and Bayesian techniques, as very close to physical boundaries subtleties in the derivation and interpretation of constraints can arise; iii) we investigate how deviations from $\Lambda$CDM, potentially alleviating these anomalies, can alter the constraints. From a profile likelihood analysis, we derive constraints in agreement at the $\sim 10\%$ level with Bayesian posteriors. We find that the weak preference for negative neutrino masses is mostly present for Planck 18 data, affected by the well-known `lensing anomaly'. It disappears when the new Planck 2020 HiLLiPoP is used, leading to significantly weaker constraints. Additionally, the pull towards negative masses in DESI data stems from the $z=0.7$ bin, which contains a BAO measurement in $\sim 3\sigma$ tension with Planck expectations. Without this bin, and in combination with HiLLiPoP, the bound relaxes to $\sum m_{\nu }<0.11\mathrm{eV}$ at 95\% CL. The recent preference for dynamical dark energy alleviates this tension and further weakens the bound. As we are at the dawn of a neutrino mass discovery from cosmology, it will be very exciting to see if this trend is confirmed by future data.

    ↳ astro-ph.COhep-exhep-phPRD(2024)·101 citations
18. 18*

    Precision String Phenomenology

    Per Berglund🇺🇸 · Giorgi Butbaia🇺🇸 · Tristan Hübsch🇺🇸 · Vishnu Jejjala🇿🇦 · Damián Mayorga Peña🇵🇹 · Challenger Mishra🇬🇧 · Justin Tan🇬🇧

    Calabi--Yau compactifications of the $E_8\times E_8$ heterotic string provide a promising route to recovering the four-dimensional particle physics described by the Standard Model. While the topology of the Calabi--Yau space determines the overall matter content in the low-energy effective field theory, further details of the compactification geometry are needed to calculate the normalized physical couplings and masses of elementary particles. In this work, we present numerical computations of physical Yukawa couplings in a number of heterotic models in the standard embedding and demonstrate the existence of natural hierarchies, a coveted feature in string model building.

    ↳ hep-thhep-phPRD(2025)·19 citations
19. 19*

    Qutrit and Qubit Circuits for Three-Flavor Collective Neutrino Oscillations

    Francesco Turro🇺🇸 · Ivan A. Chernyshev🇺🇸 · Ramya Bhaskar🇺🇸 · Marc Illa🇺🇸

    We explore the utility of qutrits and qubits for simulating the flavor dynamics of dense neutrino systems. The evolution of such systems impacts some important astrophysical processes, such as core-collapse supernovae and the nucleosynthesis of heavy nuclei. Many-body simulations require classical resources beyond current computing capabilities for physically relevant system sizes. Quantum computers are therefore a promising candidate to efficiently simulate the many-body dynamics of collective neutrino oscillations. Previous quantum simulation efforts have primarily focused on properties of the two-flavor approximation due to their direct mapping to qubits. Here, we present new quantum circuits for simulating three-flavor neutrino systems on qutrit- and qubit-based platforms, and demonstrate their feasibility by simulating systems of two, four and eight neutrinos on IBM and Quantinuum quantum computers.

    ↳ quant-phhep-phnucl-thPRD(2025)·33 citations
20. 20*

    EggNet: An Evolving Graph-based Graph Attention Network for Particle Track Reconstruction

    Paolo Calafiura🇺🇸 · Jay Chan🇺🇸 · Loic Delabrouille🇺🇸 · Brandon Wang🇺🇸

    Track reconstruction is a crucial task in particle experiments and is traditionally very computationally expensive due to its combinatorial nature. Recently, graph neural networks (GNNs) have emerged as a promising approach that can improve scalability. Most of these GNN-based methods, including the edge classification (EC) and the object condensation (OC) approach, require an input graph that needs to be constructed beforehand. In this work, we consider a one-shot OC approach that reconstructs particle tracks directly from a set of hits (point cloud) by recursively applying graph attention networks with an evolving graph structure. This approach iteratively updates the graphs and can better facilitate the message passing across each graph. Preliminary studies on the TrackML dataset show better track performance compared to the methods that require a fixed input graph.

    ↳ physics.data-ancs.LGhep-phstat.ML7 citations
21. 21*

    On gauge amplitudes first appearing at two loops

    Lance J. Dixon🇺🇸 · Anthony Morales🇺🇸

    We study scattering amplitudes in massless non-abelian gauge theory where all outgoing gluons have positive helicity. It has been argued recently by Costello that for a particular fermion representation (8 fundamentals plus one antisymmetric-tensor representation in $SU(N)$) the one-loop amplitudes vanish identically. We show that this vanishing leads to previously-observed identities among one-loop color-ordered partial amplitudes. We then turn to two loops, where Costello has computed the all-plus amplitudes for this theory, as rational functions of the kinematics for any number of gluons using the celestial chiral algebra (CCA) bootstrap. We show that in dimensional regularization, these two-loop amplitudes are not rational, and they are not even finite as $ϵ\to 0$. However, the finite remainder for four gluons agrees with the formula by Costello. In addition, we provide a mass regulator for the infrared-divergent loop integrals; with this regulator, the CCA bootstrap formula is recovered exactly. Finally, we use the CCA bootstrap to compute the double-trace terms in the theory at two loops for an arbitrary number of gluons.

    ↳ hep-thhep-phJHEP(2024)·18 citations
22. 22*

    Isotropic cosmic birefringence from an oscillating axion-like field

    Kai Murai🇯🇵

    We propose a new mechanism for isotropic cosmic birefringence with an axion-like field that rapidly oscillates during the recombination epoch. In conventional models, the field oscillation during the recombination epoch leads to a cancellation of the birefringence effect and significantly suppresses the EB spectrum of the cosmic microwave background (CMB) polarization. By introducing an asymmetric potential to the axion, this cancellation becomes incomplete, and a substantial EB spectrum can be produced. This mechanism also results in a washout of the EE spectrum, which can be probed in future CMB observations. Our findings suggest the possibility that an axion-like field responsible for isotropic cosmic birefringence can also account for a significant fraction of dark matter.

    ↳ astro-ph.COhep-phPRD(2025)·9 citations
23. 23*

    Deep learning-driven likelihood-free parameter inference for 21-cm forest observations

    Tian-Yang Sun🇨🇳 · Yue Shao🇺🇸 · Yichao Li🇺🇸 · Yidong Xu🇷🇴 · He Wang🇯🇵 · Xin Zhang🇺🇸

    The hyperfine structure absorption lines of neutral hydrogen in spectra of high-redshift radio sources, known collectively as the 21-cm forest, have been demonstrated as a sensitive probe to the small-scale structures governed by the dark matter (DM) properties, as well as the thermal history of the intergalactic medium regulated by the first galaxies during the epoch of reionization. By statistically analyzing these spectral features, the one-dimensional (1D) power spectrum of the 21-cm forest can effectively break the parameter degeneracies and constrain the properties of both DM and the first galaxies. However, conventional parameter inference methods face challenges due to computationally expensive simulations for 21-cm forest and the non-Gaussian signal characteristics. To address these issues, we introduce generative normalizing flows for data augmentation and inference normalizing flows for parameters estimation. This approach efficiently estimates parameters from minimally simulated datasets with non-Gaussian signals. Using simulated data from the upcoming Square Kilometre Array (SKA), we demonstrate the ability of the deep learning-driven likelihood-free approach to generate accurate posterior distributions, providing a robust and efficient tool for probing DM and the cosmic heating history using the 1D power spectrum of 21-cm forest in the era of SKA. This methodology is adaptable for scientific analyses with other unevenly distributed data.

    ↳ astro-ph.COgr-qchep-phCommun.Phys.(2025)·29 citations
24. 24*

    Beta-Function Dependence on Running Coupling in Holographic QCD Models

    Irina Ya. Aref'eva🇷🇺 · Ali Hajilou🇷🇺 · Pavel Slepov🇷🇺 · Marina Usova🇷🇺

    We study the dependence of beta-function on running coupling constant in holographic models supported by Einstein-dilaton-Maxwell action for light and heavy quarks. Although, in the previous paper [arXiv:2402.14512], we considered different types of the dilaton boundary conditions, but since the behavior of $\beta$-function as a function of running coupling does not depend significantly on the boundary condition, we chose one. The corresponding $\beta$-functions are negative and monotonically decreasing functions, and have jumps on the 1-st order phase transitions for both light and heavy quarks. In addition, we compare our holographic results for $\beta$-function as a function of running coupling with perturbation results that obtained within 2-loop calculations.

    ↳ hep-thhep-phTeor.Mat.Fiz.(2024)·6 citations
25. 25*

    Signatures of composite dark matter in the Cosmic Microwave Background spectral distortions

    Anoma Ganguly🇮🇳 · Rishi Khatri🇮🇳 · Tuhin S. Roy🇮🇳

    We compute the spectral distortions of the Cosmic Microwave Background (CMB) created by an exotic process that extracts or injects photons of a particular frequency into the CMB. Such signatures are a natural prediction of a class of composite dark matter models characterized by electrically neutral states but with non-zero higher order electromagnetic moments. We consider a simplified model where dark matter exists as a two state system separated by a fixed transition frequency, which can range from radio waves to gamma rays. The electromagnetic transitions between the two states due to CMB photons give rise to thermal distortions, namely, the $\mu$-type distortion in the redshift range $10^5\lesssim z\lesssim 2\times 10^6$ and the $y$-type distortion as well as non-thermal distortions at redshifts $z\lesssim 10^5$. The nature of spectral distortions depends sensitively on the dark matter transition frequency and the strength of couplings of dark matter with visible sector particles as well as its self-interactions, thus opening a new window to probe the nature of dark matter. Non-thermal distortions have unique spectral shapes making them distinguishable from the standard $\mu$ and $y$-type distortions and potentially detectable in the next-generation experiments such as Primordial Inflation Explorer (PIXIE). We also find that the spectral distortion limits from the COsmic Background Explorer/Far-Infrared Absolute Spectrophotometer (COBE/FIRAS) already give a constraint on the electromagnetic coupling of dark matter which is three orders of magnitude stronger compared to the current direct detection limits for $\sim$ MeV mass dark matter with transition energy in $\sim 1$-$10$ eV range.

    ↳ astro-ph.COhep-phPRD(2025)·1 citation
26. 26*

    Effects of primordial fluctuations on relic neutrino simulations

    Fabian Zimmer🇳🇱 · Guillermo Franco Abellán🇳🇱 · Shin'ichiro Ando🇳🇱

    After decoupling, relic neutrinos traverse the evolving gravitational imhomogeneities along their trajectories. Once they turn non-relativistic, this results in a significant amplification of the anisotropies in the cosmic neutrino background (C$\nu$B). Past studies have reconstructed the phase-space distribution of relic neutrinos from the local distribution of matter (accounting for the Milky Way halo and the surrounding large-scale structures), but have neglected the C$\nu$B anisotropies in the initial conditions of neutrino trajectories. Using our previously developed N-1-body simulation framework, we show that including these primordial fluctuations in the initial conditions can be important, as it produces similar effects on the abundance and anisotropies of the C$\nu$B as the inclusion of large-scale structures beyond the Milky Way halo. Interpretability of data from future C$\nu$B observatories like PTOLEMY therefore depends on correctly modelling these effects.

    ↳ astro-ph.COhep-phJCAP(2024)·9 citations
27. 27*

    Independent Chiral Control in Theory-Space Models:A Rank-Preserving Framework and Its Application to Neutrino Mass Generation

    Aadarsh Singh🇮🇳

    We develop a general framework of rank-preserving, element-wise matrix transformations for engineering fermion mass hierarchies in theory-space constructions. We prove that preservation of massless modes requires the transformation function to be separable, $g_f(i,j)=g_f^{(L)}(i)g_f^{(R)}(j)$, which in turn enables independent control of left- and right-chiral zero-mode profiles directly at the level of the theory-space mass matrix. This formalism unifies and extends the clockwork mechanism, permits controlled deformation of Kaluza--Klein spectra, and enhances hierarchy generation in GIM-like fine-cancellation scenarios. As a concrete application, we show that in theory-space models for neutrino masses, suitable transformations allow sub-eV light neutrinos to arise from TeV-scale new physics with only $\mathcal{O}(40)$ additional fermionic sites, while remaining consistent with charged-lepton flavor-violation bounds. In contrast, the corresponding untransformed models asymptote at the MeV scale and cannot access the phenomenologically required regime without extreme field multiplicities or hierarchical parameters.

    ↳ math.RAhep-phhep-thquant-phEPJC(2026)·1 citation

* 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.