Fri·Jan 17, 2025Friday·January 17, 2025

1. 01*

   Kinematic Moments of $\bar{B}\to X_c\ell {\bar{\nu }}_{\ell }$ to Order $\mathcal{O}({\Lambda }_{\mathrm{QCD}}^5/m_b^5)$

   Gael Finauri🇮🇹

   We investigate the heavy-quark expansion (HQE) for inclusive semileptonic $\bar{B}$ decays, at tree level, by computing the fully differential decay rate up to order $\mathcal{O}({\Lambda }_{\mathrm{QCD}}^5/m_b^5)$. We provide analytic results for the first three moments in the lepton energy, hadronic invariant mass and leptonic invariant mass ($q^2$) with a lower cut on the lepton energy in the $\bar{B}$ rest frame, as well as for the first three $q^2$ moments with a lower cut on $q^2$. By means of the lowest-lying state saturation ansatz we study the numerical behaviour of the HQE providing insights into the theoretical error budget associated with power corrections. Available CLEO data on the second central $q^2$ moment with a lower cut on the lepton energy present puzzling discrepancies with the theoretical expectations. This observation makes new measurements of these observables desirable, which could improve the precision of global fit analyses for the inclusive determination of $|V_{cb}|$.

   hep-phJHEP(2025)·5 citations
2. 02*

   Updated BBN Bounds on Hadronic Injection in the Early Universe: The Gravitino Problem

   Lucia Angel🇧🇷 · Giorgio Arcadi🇮🇹 · Matheus M. A. Paixão🇧🇷 · Farinaldo S. Queiroz🇧🇷

   Late-decaying particles naturally arise in many extensions of the Standard Model, directly impacting key cosmological processes in the early universe, such as Big Bang Nucleosynthesis (BBN). BBN studies often consider electromagnetic energy injection episodes only, but in practice long-lived particles are also amenable to hadronic decays. The latter can greatly alter the predicted abundances of light elements such as $\mathrm{D}/\mathrm{H}$, $Y_p$, ${}^3\mathrm{He}/\mathrm{D}$, and ${}^7\mathrm{Li}/\mathrm{H}$. Incorporating up-to-date measurements, we place constraints on the primordial abundance of long-lived particles as a function of their lifetime. Lastly, we apply our results to the gravitino problem and set bounds on the reheating temperature, which controls the gravitino primordial abundance.

   hep-phastro-ph.COAnnals of Physics, volume 491, pg 170516 …·7 citations
3. 03*

   Heavy quark symmetry behind $b\to c$ semileptonic sum rule

   Motoi Endo🇯🇵 · Syuhei Iguro🇯🇵 · Satoshi Mishima🇯🇵 · Ryoutaro Watanabe🇨🇳

   Lepton flavor universality violations in semileptonic $b\to c$ transitions have garnered attention over a decade. For $R_{H_c}=\mathrm{BR}(H_b\to H_c\tau {\bar{\nu }}_{\tau })/\mathrm{BR}(H_b\to H_c\ell {\bar{\nu }}_{\ell })$ with $\ell$ being $e,\mu$, a sum rule among $R_D$, $R_{D^{\ast }}$ and $R_{{\Lambda }_c}$ was proposed to check consistency in the experimental results independently of new physics models. We revisit this relation from the perspective of the heavy quark symmetry. We derive a sum rule holding exactly in the heavy quark limit and clarify how model-dependent corrections are introduced in a realistic situation.

   hep-phhep-exJHEP(2025)·15 citations
4. 04*

   Taming Penguins: Towards High Precision Measurements in ${\varphi }_d$ and ${\varphi }_s$

   Kristof De Bruyn🇳🇱 · Robert Fleischer🇳🇱 · Eleftheria Malami🇩🇪

   Experimentally, the phases ${\varphi }_d$ and ${\varphi }_s$ are determined from CP asymmetry measurements in the "golden modes" $B_d^0\to J/\psi K_{\mathrm{S}}^0$ and $B_s^0\to J/\psi \varphi$. At leading order, the theoretical interpretation of these measurements is straightforward. However, to reach high precision determinations of ${\varphi }_d$ and ${\varphi }_s$, which is essential in view of the searches for signs of beyond the SM physics, corrections from next-to-leading order effects need to be accounted for. These corrections primarily originate from so-called penguin topologies. Using the $SU(3)$ flavour symmetry, these corrections can be determined using suitably chosen control modes. Recent new CP asymmetry measurements from LHCb in $B\to DD$ and Belle-II in $B_d^0\to J/\psi {\pi }^0$ decays greatly improve our knowledge on the parameters describing the contribution from penguin topologies. These proceedings will discuss the current constraints on the penguin parameters in $B\to J/\psi X$ and $B\to DD$ decays, provide corrected determinations for ${\varphi }_d$ and ${\varphi }_s$, and highlight what can be expected at the end of the HL-LHC and Belle-II programmes.

   hep-phPoS(2025)·1 citation
5. 05*

   Role of $a_0(1710)$ in the $D_s^{+}\to {\rho }^{+}\varphi ,{\rho }^{+}\omega$ decays

   Jing Song🇨🇳 · Zi-Ying Yang🇨🇳 · Eulogio Oset🇪🇸

   We look into the $D_s^{+}\to {\rho }^{+}\varphi$ and $D_s^{+}\to {\rho }^{+}\omega$ weak decays recently measured by the BESIII collaboration, which proceed very differently in a first step of the weak decay. While the first reaction proceeds directly via external emission, the second one does not go via external nor internal emission, what prompted the experimental team to claim that it proceeds via $W-$annihilation. We show in this work that the unexpectedly large rate of the $D_s^{+}\to {\rho }^{+}\omega$, should it be due to $W-$annihilation, has a different explanation since is it naturally obtained once final state interaction of the ${\rho }^{+}\varphi ,{\rho }^{+}\omega$ and $K^{\ast +}{\bar{K}}^{\ast 0}$ channels is taken into consideration. The interaction of these channels produces the $a_0(1710)$ resonance, predicted long ago as a molecular state of these coupled channels, and only recently observed, and it is the presence of this resonance what makes the effect of the final state interaction very important in the weak decays and provides a natural explanation of the experimental decay rates.

   hep-phPRD(2025)·4 citations
6. 06*

   The flux of electron antineutrinos from supernova SN1987A data

   Riccardo Maria Bozza🇮🇹 · Vigilante di Risi🇮🇹 · Giuseppe Matteucci🇮🇹 · Veronica Oliviero🇮🇹 · Giulia Ricciardi🇮🇹 · Francesco Vissani🇮🇹

   By adopting a state-of-the-art parameterized model of electron antineutrino emission, we have made some steps forward in the analysis of the thermodynamical properties and temporal structure of neutrino emission from core collapse SN1987A. Our analysis, unlike similar previous ones, takes into account the times, energies and angles of arrival of the detected events in a reliable framework which includes a finite ramp in the initial stage of the neutrino emission. The existence of the accretion phase is confirmed with a confidence level of about 99%, and the neutrons involved in the emission during accretion, for the first time, do not show significant tensions with expectations, being about 0.02 $M_{\odot }$. We determine the parameters of the cooling emission and discuss its duration, that compares well with theoretical expectations. We estimate the delay times between the first neutrino and the first event in the detectors. The goodness of fit checks, performed on the temporal, energy and angular distributions, show that the flux resulting from the best-fit analysis is compatible with the observed data.

   hep-phastro-ph.HEhep-exJCAP(2025)·7 citations
7. 07*

   Exclusive quarkonium photoproduction: predictions with the Balitsky-Kovchegov equation including the full impact-parameter dependence

   J. Cepila🇨🇿 · J. G. Contreras🇨🇿 · M. Vaculciak🇨🇿

   The ongoing Run 3 at the Large Hadron Collider (LHC) is substantially increasing the luminosity delivered to the experiments during Run 1 and Run 2. The advent of the high-luminosity upgrade of the LHC (Run 4 to 6), as well as the improvements to all detectors, will allow for the collection of an unprecedented amount of data in the next decade. This opens the possibility of performing measurements which have been limited by the smallness of the available data samples. This is the case of multi-differential studies of $J/\psi$, as well as of ${\rm Y}$ excited states, in exclusive diffractive photon-induced interactions. Here, we present predictions for the cross-sections of these processes utilising the dipole amplitude from the Balitsky-Kovchegov (BK) equation solved in the target rapidity and including the full impact-parameter dependence. Cross-sections are computed as a function of the photon--proton centre-of-mass energy as well as a function of Mandelstam-$t$. Ratios of cross-sections for different states and for the same state at different Mandelstam-$t$ values are also presented. The contribution to these observables of the non-linear terms in the BK equation is discussed.

   hep-phPRD(2025)·7 citations
8. 08*

   Gravitational waves and dark matter with Witten effect

   Ruiyu Zhou🇨🇳 · Ligong Bian🇨🇳

   We investigate the breaking of dark $SU(2{)}_d$ symmetry at different temperature scales, occurring after Peccei-Quinn symmetry breaking or following QCD symmetry breaking. We focus on assessing the potential of the hidden monopoles generated during this process to serve as dark matter candidate. Additionally, we examine the impact of axion-monopole interactions on the axion mass. When the phase transition occurs at extremely high temperature ($\sim 10^8\mathrm{GeV}$), the contribution of monopoles to the axion mass through witten effect becomes non-negligible, playing a crucial role in accurately determining the axion relic density. Moreover, the stochastic gravitational wave background generated by dark phase transition and axionic domain wall collapse may offer a potential explanation for the low-frequency gravitational wave signals observed in PTA experiments.

   hep-phastro-ph.COhep-thCPC(2025)·3 citations
9. 09*

   Scattering meets absorption in dark matter detection

   Pieter Braat🇳🇱 · Anh Vu Phan🇳🇱 · Marieke Postma🇳🇱 · Susanne Westhoff🇳🇱

   Direct detection experiments have started to explore dark matter scattering off electrons and nucleons through light mediators. Mediators with sub-keV masses are efficiently produced in the Sun and can be absorbed in the same detectors that probe dark matter scattering. We investigate the interplay of dark matter scattering and mediator absorption for two models with a dark photon as mediator. For Dirac dark matter, we find that scattering and absorption can be simultaneously observed at direct detection experiments in the near future. For atomic dark matter, we predict additional signals due to scattering of both dark atoms and constituents from ionized dark atoms. In both models, we determine the parameter space that respects bounds from cosmology and astrophysics, where the strongest constraints come from dark matter self-interactions. In this way, we identify viable targets for dark matter with light mediators at upcoming direct detection experiments. Distinguishing between the various signals, for instance by measuring energy distributions, will be crucial to reveal the underlying model in case of a discovery.

   hep-phastro-ph.COhep-exJHEP(2025)·2 citations
10. 10*

    Dispersive analysis of the pion vector form factor without zeros

    Thomas P. Leplumey🇨🇭 · Peter Stoffer🇨🇭

    We perform an updated analysis of $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ cross-section data using a dispersive representation of the pion vector form factor. We show that the available data are compatible with the assumption that the form factor is free of complex zeros and that under this assumption the largest systematic uncertainty in a previous analysis can be eliminated. We investigate both a constrained Omnès representation as well as a hybrid phase-modulus representation and we quantify the discrepancies in the hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon based on different $e^{+}{e}^{-}$ data sets. We find that the dispersive constraints exacerbate these discrepancies. Together with the assumption of the absence of zeros, the pion charge radius becomes a useful observable to discriminate between the different data sets. This provides an opportunity for future improved lattice-QCD determinations to probe the discrepancies independently of full computations of hadronic vacuum polarization. We also reevaluate the two-pion contribution to Euclidean windows and we observe that systematic discrepancies between the data sets persist even at very long distances.

    hep-phhep-exhep-latnucl-th26 citations
11. 11*

    Constraining the Secluded and Catalyzed Annihilation Dark Matter with Fermi-LAT and Planck Data

    Yu-Hang Su🇨🇳 · Chengfeng Cai🇨🇳 · Hong-Hao Zhang🇨🇳

    We propose a dark matter (DM) model with a complex scalar charged under a hidden gauge symmetry, denoted as $U(1{)}_D$. The scalar field is the DM candidate while the $U(1{)}_D$ gauge field $A^{\prime }$ plays the role of a mediator, which connects the dark sector to the standard model (SM) sector via a tiny kinetic mixing. We find that both the secluded and catalyzed annihilation scenarios can be realized in this model. The phenomenology of DM, including relic density, indirect detection (Fermi-LAT), and CMB (Planck) constraints, is discussed. We also extend our discussion to DM with other spins, including Dirac fermion and vector boson. Our analysis is carried out in two models, denoted as $U(1{)}_D\times U(1{)}_Y$ and $U(1{)}_D\times U(1{)}_{L_{\mu }-L_{\tau }}$, with the former corresponding to $A^{\prime }$ kinetically mixing with the $U(1{)}_Y$ gauge field $B$ and the latter corresponding to $A^{\prime }$ mixing with the $U(1{)}_{L_{\mu }-L_{\tau }}$ gauge field $Z^{\prime }$. We find that, in previous studies, the indirect detection limits were overly restrictive because they only considered the simplified $2\mathrm{DM}\to 2\mathrm{SM}$ annihilation channel. In contrast, by performing a complete calculation of the gamma-ray and CMB constraints from the process $2\mathrm{DM}\to 2A^{\prime }\to 4\mathrm{SM}$ in the models we consider, we observe weaker constraints in both the $U(1{)}_D\times U(1{)}_Y$ and $U(1{)}_D\times U(1{)}_{L_{\mu }-L_{\tau }}$ models, with the $U(1{)}_D\times U(1{)}_{L_{\mu }-L_{\tau }}$ model being subject to the weakest constraints overall since it involves less hadronic decay processes.

    hep-phastro-ph.COastro-ph.HEhep-exPRD(2025)·5 citations
12. 12*

    Tensor meson transition form factors in holographic QCD and the muon $g-2$

    Luigi Cappiello🇮🇹 · Josef Leutgeb🇦🇹 · Jonas Mager🇦🇹 · Anton Rebhan🇦🇹

    Despite the prominence of tensor mesons in photon-photon collisions, until recently their contribution to the hadronic light-by-light (HLbL) scattering part of the anomalous magnetic moment of the muon has been estimated to be at the level of only a few $10^{-12}$. A recent reanalysis within the dispersive approach has found that after resolving the issue of kinematic singularities in previous approaches, a larger result is obtained, a few $10^{-11}$, and with opposite sign as in previous results, when a simple quark model for the transition form factors is employed. In this paper, we present the first complete evaluation of tensor meson contributions within a hard-wall model in holographic QCD, which reproduces surprisingly well mass, two-photon width, and the observed singly virtual transition form factors of the dominant $f_2(1270)$. Due to a second structure function that is absent in the quark model and in lowest-order resonance chiral theory, the result for $a_{\mu }$ turns out to be positive instead of negative, and also with a magnitude of a few $10^{-11}$. We find that the infinite tower of tensor mesons permits to fill the gap in the symmetric longitudinal short-distance constraint on the HLbL amplitude left by the contribution of axial vector mesons. Matching the corresponding leading-order OPE result leads to two-photon couplings consistent with the observed combined effects of the ground-state $f_2,a_2,f_2^{\prime }$ multiplet and a total $a_{\mu }^{\mathrm{Tensor}}$ contribution of $+12.4\times 10^{-11}$; with an $F_{\rho }$ fit this is reduced slightly to $+11.1\times 10^{-11}$. A contribution of this size from the tensor sector could explain the tension between the most recent dispersive and lattice results for $a_{\mu }^{\mathrm{HLbL}}$.

    hep-phJHEP(2025)·39 citations
13. 13*

    Partonic distribution functions and amplitudes using tensor network methods

    Zhong-Bo Kang🇺🇸 · Noah Moran🇺🇸 · Peter Nguyen🇺🇸 · Wenyang Qian🇪🇸

    Calculations of the parton distribution function (PDF) and distribution amplitude (DA) are highly relevant to core experimental programs as they provide non-perturbative inputs to inclusive and exclusive processes, respectively. Direct computation of the PDFs and DAs remains challenging because they are non-perturbative quantities defined as light-cone correlators of quark and gluon fields, and are therefore inherently time-dependent. In this work, we use a uniform quantum strategy based on tensor network simulation techniques to directly extract these hadronic quantities from first principles using the matrix product state of the hadrons in the same setup. We present exemplary numerical calculations with the Nambu-Jona-Lasinio model in 1+1 dimensions and compare with available exact diagonalization and quantum circuit simulation results. Using tensor networks, we evaluate the PDF and DA at various strong couplings in the large-qubit limit, which is consistent with expectations at perturbative and non-relativistic limits.

    hep-phhep-latnucl-thquant-phJHEP(2025)·19 citations
14. 14*

    Search for $K_{S,L}$ oscillations and invisible decays into the dark sector at NA64

    S.N. Gninenko🇷🇺 · N.V. Krasnikov🇷🇺 · V.A. Matveev🇷🇺

    The decays $K_{S,L}$ have never been experimentally tested. In the Standard Model their branching ratios for the decay into two neutrinos are predicted to be extremely small, $Br(K_{S,L}\to \nu \bar{\nu })\lesssim 10^{-16}$. We consider several natural extensions of the SM, such as two-Higgs-doublet (2HDM), 2HDM and light scalar, and dark mirror sector models, that allow to enhance the $Br(K_{S,L})$ up to a measurable level. We briefly discuss the possible search for $K_{S,L}$ decays and $K_{S,L}$ oscillations into the dark sector at the NA64 experiment at CERN with the sensitivity to $Br(K_{S,L})\lesssim 10^{-7}-10^{-5}$.

    hep-phhep-exNatural Sci.Rev.(2024)·4 citations
15. 15*

    Systematic Spurion Matching between Low Energy EFT and Chiral Lagrangian

    Chuan-Qiang Song🇨🇳 · Hao Sun🇨🇳 · Jiang-Hao Yu🇨🇳

    The hadronic chiral Lagrangian can be matched from the low energy effective field theory (LEFT) operators at the quark level. Traditionally, as the mass dimension of the LEFT operators increases, more and more external sources are necessarily introduced in the chiral perturbation theory (ChPT). In this work, we present a systematic matching procedure with the single spurion field $\mathbf{T}$ of the flavor $SU(3{)}_V$ octet, without the need of external sources. We present the complete sets of the LEFT operators, which have been reformulated using the flavor $SU(3{)}_V$ symmetry up to dimension 9. At the same time, the ChPT Lagrangian is also reformulated using the single spurion and lepton fields, instead of external sources. The spurion matching can be performed between LEFT and ChPT operators with the same flavor $SU(3{)}_V$ and $CP$ structures, and the same leptonic currents, using the naive dimensional analysis at the quark and hadronic levels.

    hep-ph7 citations
16. 16*

    Optical gravitational waves as signals of Gravitationally-Decaying Particles

    Giacomo Landini🇪🇸 · Alessandro Strumia🇮🇹

    Long-lived heavy particles present during the big bang could have a decay channel opened by gravitons. Such decays can produce gravitational waves with large enough abundance to be detectable, and a peculiar narrow spectrum peaked today around optical frequencies. We identify which particles can decay in one or two gravitons. The maximal gravitational wave abundance arises from theories with extra hidden strong gauge dynamics, such as a confining pure-glue group. An interesting abundance also arises in theories with perturbative couplings. Future observation might shed light on early cosmology and allow some spectroscopy of sub-Planckian gravitationally-decaying particles, plausibly present in a variety of theories such as gauge unification, supersymmetry, extra dimensions, strings.

    hep-phastro-ph.COhep-thJHEP(2025)·17 citations
17. 17*

    Drell-Yan constraints on charged scalars: a weak isospin perspective

    Avik Banerjee🇮🇳 · Dipankar Das🇮🇳 · Samadrita Mukherjee🇮🇳 · Shreya Pandey🇮🇳

    Charged scalars appear in many motivated extensions beyond the Standard Model. We analyze the constraints on charged scalar pair production via the Drell-Yan process at the Large Hadron Collider and interpret them in terms of weak isospin quantum numbers. Leveraging the experimental limits from existing LHC data and phenomenological recast analyses, we place bounds on the branching ratio of the charged scalar, as a function of its mass, electric charge, and isospin. This approach enables to determine limits on the branching ratios directly from experimental data, without appealing to a specific model. We provide a detailed analysis for singly and doubly charged scalars across various weak isospin scenarios, focusing on decays into leptonic and bosonic final states, and validate this approach in extended Higgs sectors such as the Higgs triplet model and Georgi-Machacek model.

    hep-phhep-exPRD(2025)·2 citations
18. 18*

    Cosmological Interactions with Phantom Scalar Field: Revisiting Background Phase-Space Analysis with Compactified Variables

    Genly Leon🇨🇱 · Daya Shankar🇮🇳 · Amlan Halder🇮🇳 · Andronikos Paliathanasis🇿🇦

    Energy transfer in the dark sector of the universe gives rise to new phenomena of special interest in modern cosmology. When dark energy is modeled as a phantom scalar field, interactions become crucial to avoid Big Rip singularities. In this work, we revisit the phase-space analysis of the field equations by introducing a new set of dimensionless variables distinct from the traditional Hubble normalization approach. These new variables define a compactified phase space for the evolution of physical parameters. We demonstrate that these compactified variables offer fresh insights into the phase-space analysis in gravitational theories, particularly when the dark energy fluid is allowed to possess a negative kinetic energy density.

    ↳ gr-qcastro-ph.COhep-phChaos Solitons Fractals(2025)·8 citations
19. 19*

    Effect of accretion on scalar superradiant instability

    Yin-Da Guo🇨🇳 · Shou-Shan Bao🇨🇳 · Tianjun Li🇨🇳 · Hong Zhang🇨🇳

    Superradiance can lead to the formation of a black hole (BH) condensate system. We thoroughly investigate the accretion effect on the evolution of this system, and the gravitational wave signals it emits in the presence of multiple superradiance modes. Assuming the multiplication of the BH mass and scalar mass as a small number, we obtain the analytical approximations of all important quantities, which can be directly applied to phenomenological studies. In addition, we confirm that accretion could significantly enhance the gravitational wave (GW) emission and reduce its duration, and show that the GW beat signature is similarly modified.

    ↳ gr-qchep-phJCAP(2025)·9 citations
20. 20*

    Cosmological Solutions in Scalar-Tensor theory via the Eisenhart-Duval lift

    Andronikos Paliathanasis🇿🇦

    We implement the Einsenhart-Duval lift in scalar-tensor gravity as a means to construct integrable cosmological models and analytic cosmological solutions. Specifically, we employ a geometric criterion to constrain the free functions of the scalar-tensor theory such that the field equations can be written in the equivalent form of linear equations. This geometric linearization is achieved by the introduction of an extended minisuperspace description. The results are applied to construct analytic solutions in modified theories of gravity such as the $f\left(R\right)$-theory and the hybrid metric-Palatini $f\left(\mathcal{R}\right)$-gravity.

    ↳ gr-qchep-phmath-phmath.MPMod.Phys.Lett.A(2025)·4 citations
21. 21*

    Reassessing aspects of the photon's LQG-modified dispersion relations

    P. A. L. Mourão🇧🇷 · G. L. L. W. Levy🇧🇷 · J. A. Helayël-Neto🇧🇷

    Our present contribution sets out to investigate a scenario based on the effects of the Loop Quantum Gravity (LQG) on the electromagnetic sector of the Standard Model of Fundamental Interactions and Particle Physics (SM). Starting then from a post-Maxwellian version of Electromagnetism that includes LQG effects, we work out and discuss the influence of LQG parameters on classical quantities, such as the components of the stress-tensor. Furthermore, we inspect the propagation of electromagnetic waves and study optical properties of the QED vacuum in this scenario. Among these, we contemplate the combined effect between the LQG parameters and a homogeneous background magnetic field on the propagation of electromagnetic waves, considering in detail issues like group velocities and refractive indices of the QED vacuum. Finally, with the help of the LQG-extended photonic dispersion relations previously analyzed, we re-discuss the kinematics of the Compton effect and conclude that there emerges an interesting nonlinear profile in the wavelengths of both the incoming and the deflected photons.

    ↳ hep-thgr-qchep-phCPC(2026)·2 citations
22. 22*

    A Unified View of Vacuum Decay Channels

    J.R. Espinosa🇪🇸

    The tunneling potential formalism, an alternative to the standard Coleman Euclidean approach, offers in a natural way a unified view of vacuum decays. In particular, I show in this talk how Coleman's bounce is just a member of a continuous family of solutions that can also feature Hawking-Moss instantons, pseudo-bounces and bubble-of-nothing solutions.

    ↳ hep-thhep-ph1 citation
23. 23*

    Generating particle physics Lagrangians with transformers

    Yong Sheng Koay🇸🇪 · Rikard Enberg🇸🇪 · Stefano Moretti🇬🇧 · Eliel Camargo-Molina🇸🇪

    In physics, Lagrangians provide a systematic way to describe laws governing physical systems. In the context of particle physics, they encode the interactions and behavior of the fundamental building blocks of our universe. By treating Lagrangians as complex, rule-based constructs similar to linguistic expressions, we trained a transformer model -- proven to be effective in natural language tasks -- to predict the Lagrangian corresponding to a given list of particles. We report on the transformer's performance in constructing Lagrangians respecting the Standard Model $\mathrm{SU}(3)\times \mathrm{SU}(2)\times \mathrm{U}(1)$ gauge symmetries. The resulting model is shown to achieve high accuracies (over 90\%) with Lagrangians up to six matter fields, with the capacity to generalize beyond the training distribution, albeit within architectural constraints. We show through an analysis of input embeddings that the model has internalized concepts such as group representations and conjugation operations as it learned to generate Lagrangians. We make the model and training datasets available to the community. An interactive demonstration can be found at: \url{https://huggingface.co/spaces/JoseEliel/generate-lagrangians}.

    ↳ cs.LGcs.SChep-phhep-thSciPost Phys.(2026)·3 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.