Mon·Jan 13, 2025Monday·January 13, 2025

1. 01*

   OmniJet-${\alpha }_C$: Learning point cloud calorimeter simulations using generative transformers

   Joschka Birk🇩🇪 · Frank Gaede🇩🇪 · Anna Hallin🇩🇪 · Gregor Kasieczka🇩🇪 · Martina Mozzanica🇩🇪 · Henning Rose🇩🇪

   We show the first use of generative transformers for generating calorimeter showers as point clouds in a high-granularity calorimeter. Using the tokenizer and generative part of the OmniJet-$\alpha$ model, we represent the hits in the detector as sequences of integers. This model allows variable-length sequences, which means that it supports realistic shower development and does not need to be conditioned on the number of hits. Since the tokenization represents the showers as point clouds, the model learns the geometry of the showers without being restricted to any particular voxel grid.

   hep-phcs.LGhep-exphysics.ins-detJINST(2025)·25 citations
2. 02*

   CP violation analysis of $D^0\to M^{0}K\to M^0({\pi }^{\pm }{\ell }^{\mp }\nu )$

   Wen-Jie Song🇨🇳 · Shi-Qi Wang🇨🇳 · Qin Qin🇨🇳 · Ya Li🇨🇳

   CP violation in the charm sector is highly sensitive to new physics due to its small predicted value within the standard model. By this work, we investigated the CP violation in the cascade decay process $D^0(t_1)\to {\pi }^{0}K(t_2)\to {\pi }^0({\pi }^{\pm }{\ell }^{\mp }\nu )$. Our results indicate that the CP violation induced by the interference of unmixed $D$-meson decay amplitudes dominates, with a peak value reaching $5\times 10^{-3}$. This is one order of magnitude larger than the sub-leading contribution, namely the double-mixing CP violation. Furthermore, the CP violation in the decay channel with the semileptonic final state ${\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ is one to two orders of magnitude larger than that in the channel with ${\pi }^{+}{\ell }^{-}{\bar{\nu }}_{\ell }$. We propose that the CP asymmetry of the combined two decay channels can be measured experimentally. The resulting value is approximately half of the CP violation observed in the ${\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ channel, with the dominant contribution still reaching the order of $10^{-3}$. This approach offers the advantage of eliminating the need for flavor tagging of the initial $D$ meson, thereby avoiding associated efficiency losses.

   hep-phEPJC(2025)·5 citations
3. 03*

   Dark matter stabilized by a non-abelian group: lessons from the $\Sigma (36)$ 3HDM

   Hong Deng🇨🇳 · Rafael Boto🇵🇹 · Igor P. Ivanov🇨🇳 · João P. Silva🇵🇹

   When building dark matter (DM) models, one often imposes conserved discrete symmetries to stabilize DM candidates. The simplest choice is ${\mathbb{Z}}_2$ but models with larger stabilizing groups have also been explored. Can a conserved non-abelian group lead to a viable DM model? Here, we address this question within the three-Higgs-doublet model based on the group $\Sigma (36)$, in which DM stabilization by a non-abelian group is not only possible but inevitable. We show that the tight connections between the Higgs, fermion, and DM sectors repeatedly drive the model into conflict with the LHC results and DM observations, with the most recent LZ results playing a decisive role. We believe that the lessons learned from this study help chart the limits of what can be achieved within multi-Higgs-doublet DM models with large symmetry groups.

   hep-phPRD(2025)·6 citations
4. 04*

   Flavor-changing Lorentz and CPT violation in muonic atoms

   Alan Kostelecky🇺🇸 · W.P. McNulty🇺🇸 · E. Passemar🇺🇸 · N. Sherrill🇬🇧

   Flavor-changing signatures of Lorentz and CPT violation involving muon-electron conversions in muonic atoms are studied using effective field theory. Constraints on coefficients for Lorentz violation at parts in $10^{-12}$ GeV${}^{-1}$ for flavor-changing electromagnetic muon decays and parts in $10^{-13}$ GeV${}^{-2}$ for flavor-changing 4-point quark-lepton interactions are extracted using existing data from the SINDRUM II experiment at the Paul Scherrer Institute. Estimates are provided for sensitivities attainable in the forthcoming experiments Mu2e at Fermilab and COMET at the Japan Proton Accelerator Complex.

   hep-phPLB(2025)·5 citations
5. 05*

   The all-charm tetraquark and its contribution to two-photon processes

   Panagiotis Kalamidas🇩🇪 · Marc Vanderhaeghen🇩🇪

   Prompted by several potential tetraquark states that have been reported by the LHCb, CMS and ATLAS collaborations in the di-$J/\Psi$ and $J/\Psi \Psi (2S)$ spectra, we investigate their contribution to two-photon processes. Within a non-relativistic potential model for the all-charm tetraquark states, we calculate the two-photon decay widths of these states, and test model independent sum rule predictions. Imposing such sum rule constraints allows us to predict the light-by-light scattering cross sections in a consistent way and check if any excess, in comparison to the Standard Model prediction, as reported by ongoing ATLAS experiments can be attributed to intermediate exotic states.

   hep-phPRD(2025)·4 citations
6. 06*

   Scattering with total depletion in strong, focussed fields

   Tim Adamo🇬🇧 · Anton Ilderton🇬🇧

   Theoretical approaches to QED scattering in strong fields typically treat the field as a fixed background with simple spacetime dependence, such as a plane wave. Two major challenges are therefore the inclusion of backreaction (e.g. depletion of the field) and spatial geometry (e.g. focussing). We show here that a solution to one problem can solve the other: even if particle wavefunctions in a chosen focussed background are not known, we show they can be constructed once depletion is accounted for. We demonstrate this by giving the exact wavefunctions in a flying focus beam for which all energy is absorbed by particles scattering on it. In addition we use the wavefunctions to obtain a simple expression for the nonlinear Compton scattering amplitude, comparing with the plane wave case. Our methods thus open a new avenue of investigation in which two previously challenging effects are simultaneously brought under analytic control.

   hep-phhep-thPRD(2025)·11 citations
7. 07*

   Dynamics of Heavy Quarks in Strongly Coupled $\mathcal{N}=4$ SYM Plasma

   Krishna Rajagopal🇺🇸 · Bruno Scheihing-Hitschfeld🇺🇸 · Urs Achim Wiedemann🇨🇭

   We calculate the probability distribution $P(\mathbf{k})$ for a heavy quark with velocity $v$ propagating through strongly coupled $\mathcal{N}=4$ SYM plasma in the 't Hooft limit at a temperature $T$ to acquire a momentum $\mathbf{k}$ due to interactions with the plasma. This distribution encodes the well-known drag coefficient ${\eta }_D$ and the transverse and longitudinal momentum diffusion coefficients ${\kappa }_T$ and ${\kappa }_L$. Furthermore, our calculation determines all of the higher order and mixed moments to leading order in $1/\sqrt{\lambda }$ for the first time. These non-Gaussian features of $P(\mathbf{k})$ include qualitatively novel correlations between longitudinal energy loss and transverse momentum broadening at nonzero $v$. We demonstrate that these non-Gaussian characteristics can be sizable in magnitude and even dominant in physically relevant situations. We use these results to derive a Kolmogorov equation for the evolution of the probability distribution for the total momentum of a heavy quark that propagates through strongly coupled plasma. This evolution equation accounts for all higher order correlations between transverse momentum broadening and longitudinal energy loss, which we have calculated from first principles. It reduces to a Fokker-Planck (FP) equation when truncated to only include the effects of ${\eta }_D$, ${\kappa }_T$ and ${\kappa }_L$. Remarkably, while heavy quarks do not reach kinetic equilibrium with the plasma if evolved with this FP equation, we demonstrate that heavy quarks do reach kinetic equilibrium if evolved with the all-order Kolmogorov equation we have derived. Our results thus provide a dynamically complete framework for understanding the thermalization of a heavy quark that may be initially far from equilibrium in the strongly coupled $\mathcal{N}=4$ SYM plasma -- as well as new insight into heavy quark transport and equilibration in quark-gluon plasma.

   hep-phhep-thnucl-thJHEP(2025)·16 citations
8. 08*

   Probing axion and flavored new physics with the NA64$\mu$ experiment

   Haotian Li🇨🇳 · Zuowei Liu🇨🇳 · Ningqiang Song🇨🇳

   High-energy muon beam dump experiments are powerful probes of new physics models beyond the Standard Model, particularly those involving flavor-dependent interactions. We demonstrate the potential of muon beam dump by placing strong constraints on three new physics models utilizing data from the recent NA64$\mu$ experiment: (1) axions coupling to photons, (2) axions coupling to muons, and (3) a dark sector mediated by a massless $U(1{)}_{L_{\mu }-L_{\tau }}$ gauge boson. The new particles can be identified from the significant missing energy as the invisible channel, or the distinct energy deposition signature as the visible channel. We find that the current NA64$\mu$ data do not yet probe new parameter region on axion-photon coupling, while excluding new parameter space for the axion-muon coupling $g_{a\mu \mu }\gtrsim 4\times 10^{-3}$~GeV${}^{-1}$ and the axion mass $m_a\lesssim 0.2$~GeV. For the dark sector, the current data provide stringent constraints that surpass existing ones by nearly one order of magnitude. The data from the 2023 NA64$\mu$ run, once available, will be capable of excluding new axion-photon coupling parameter space and probing the flavor structure of new physics, with more sensitivity advancement expected in near future runs.

   hep-phhep-exPRD(2025)·10 citations
9. 09*

   Impact of memory-burdened primordial black holes on high-scale leptogenesis

   Roberta Calabrese🇮🇹 · Marco Chianese🇮🇹 · Ninetta Saviano🇮🇹

   We explore the impact of the back-reaction of evaporation on the quantum state of Primordial Black Holes (PBHs), known as ``memory burden", on the baryon asymmetry production in the Universe through high-scale leptogenesis. Focusing on PBH masses ranging from 1 to 1000 grams, we investigate the interplay between the non-thermal production of heavy sterile neutrinos and the entropy injection within this non-standard cosmological framework. By assuming appropriate values for the memory-burden parameters, $q=1/2$ and $k=1$, we derive mutual exclusion limits between PBHs and thermal leptogenesis in the mixed parameter space. Our analysis reveals that the primary contribution of PBHs to baryon asymmetry stems from entropy injection. Indeed, we find that, differently from earlier studies based on the semi-classical Hawking evaporation, the memory-burden effect suppresses the non-thermal source term in the PBH mass range explored. This has significant implications for understanding baryogenesis in such alternative cosmological scenarios.

   hep-phastro-ph.COhep-thPRD(2025)·26 citations
10. 10*

    Primordial Black Hole Hot Spots and Nucleosynthesis

    Clelia Altomonte🇬🇧 · Malcolm Fairbairn🇬🇧 · Lucien Heurtier🇬🇧

    Upon their evaporation via Hawking radiation, primordial black holes (PBHs) may deposit energy in the ambient plasma on scales smaller than the typical distance between two black holes, leading to the formation of hot spots around them. We investigate how the corresponding rise of the local temperature during the evaporation may act as a shield against the release of low-energy photons, affecting PBH's capacity to dissociate light nuclei after Big-Bang Nucleosynthesis through photo-dissociation. We study the different ways PBH hot spots affect the flux of low-energy photons expected from PBH evaporation, and we find that such effects can be particularly relevant to the physics of photo-dissociation during Big-Bang Nucleosynthesis for PBHs with masses between $10^{11}$g and $3\times 10^{12}$g. We emphasize that the magnitude of this effect is highly dependent on the specific shape of the temperature profile around PBHs and its time evolution. This underscores the necessity for a comprehensive study of PBH hot spots and their dynamics in the future.

    ↳ astro-ph.COhep-phPRD(2025)·7 citations
11. 11*

    Physics-Driven Learning for Inverse Problems in Quantum Chromodynamics

    Gert Aarts🇬🇧 · Kenji Fukushima🇯🇵 · Tetsuo Hatsuda🇯🇵 · Andreas Ipp🇦🇹 · Shuzhe Shi🇨🇳 · Lingxiao Wang🇯🇵 · Kai Zhou🇩🇪

    The integration of deep learning techniques and physics-driven designs is reforming the way we address inverse problems, in which accurate physical properties are extracted from complex data sets. This is particularly relevant for quantum chromodynamics (QCD), the theory of strong interactions, with its inherent limitations in observational data and demanding computational approaches. This perspective highlights advances and potential of physics-driven learning methods, focusing on predictions of physical quantities towards QCD physics, and drawing connections to machine learning(ML). It is shown that the fusion of ML and physics can lead to more efficient and reliable problem-solving strategies. Key ideas of ML, methodology of embedding physics priors, and generative models as inverse modelling of physical probability distributions are introduced. Specific applications cover first-principle lattice calculations, and QCD physics of hadrons, neutron stars, and heavy-ion collisions. These examples provide a structured and concise overview of how incorporating prior knowledge such as symmetry, continuity and equations into deep learning designs can address diverse inverse problems across different physical sciences.

    ↳ hep-latcs.LGhep-phnucl-thNature Rev.Phys.(2025)·53 citations
12. 12*

    Automatizing the search for mass resonances using BumpNet

    Jean-Francois Arguin · Georges Azuelos · Émile Baril · Ilan Bessudo · Fannie Bilodeau · Maryna Borysova · Shikma Bressler · Samuel Calvet · Julien Donini · Etienne Dreyer · Michael Kwok Lam Chu · Eva Mayer and 6 other authors

    The search for resonant mass bumps in invariant-mass distributions remains a cornerstone strategy for uncovering Beyond the Standard Model (BSM) physics at the Large Hadron Collider (LHC). Traditional methods often rely on predefined functional forms and exhaustive computational and human resources, limiting the scope of tested final states and selections. This work presents BumpNet, a machine learning-based approach leveraging advanced neural network architectures to generalize and enhance the Data-Directed Paradigm (DDP) for resonance searches. Trained on a diverse dataset of smoothly-falling analytical functions and realistic simulated data, BumpNet efficiently predicts statistical significance distributions across varying histogram configurations, including those derived from LHC-like conditions. The network's performance is validated against idealized likelihood ratio-based tests, showing minimal bias and strong sensitivity in detecting mass bumps across a range of scenarios. Additionally, BumpNet's application to realistic BSM scenarios highlights its capability to identify subtle signals while managing the look-elsewhere effect. These results underscore BumpNet's potential to expand the reach of resonance searches, paving the way for more comprehensive explorations of LHC data in future analyses.

    ↳ physics.data-anhep-exhep-phJHEP(2025)·2 citations
13. 13*

    Black String in the Standard Model

    Yu Hamada🇩🇪 · Yuta Hamada🇯🇵 · Hayate Kimura🇯🇵

    The Swampland cobordism conjecture predicts various new objects in a theory with dynamical gravity. Applying this idea to the Standard Model of particle physics, a string object is predicted. We numerically constructed such an object as a black string solution.

    ↳ hep-thhep-phPRD(2025)·4 citations
14. 14*

    Recurrent Features of Amplitudes in Planar $\mathcal{N}=4$ Super Yang-Mills Theory

    Tianji Cai🇺🇸 · François Charton🇩🇪 · Kyle Cranmer🇺🇸 · Lance J. Dixon🇺🇸 · Garrett W. Merz🇺🇸 · Matthias Wilhelm🇩🇰

    The planar three-gluon form factor for the chiral stress tensor operator in planar maximally supersymmetric Yang-Mills theory is an analog of the Higgs-to-three-gluon scattering amplitude in QCD. The amplitude (symbol) bootstrap program has provided a wealth of high-loop perturbative data about this form factor, with results up to eight loops available. The symbol of the form factor at $L$ loops is given by words of length $2L$ in six letters with associated integer coefficients. In this paper, we analyze this data, describing patterns of zero coefficients and relations between coefficients. We find many sequences of words whose coefficients are given by closed-form expressions which we expect to be valid at any loop order. Moreover, motivated by our previous machine-learning analysis, we identify simple recursion relations that relate the coefficient of a word to the coefficients of particular lower-loop words. These results open an exciting door for understanding scattering amplitudes at all loop orders.

    ↳ hep-thhep-phJHEP(2025)·9 citations
15. 15*

    Classification of $T^2/Z_m$ orbifold boundary conditions in $SO(N)$ gauge theories

    Kota Takeuchi🇯🇵 · Tomohiro Inagaki🇯🇵

    We generally classify the equivalence classes of the $T^2/Z_m$ $(m=2,3,4,6)$ orbifold boundary conditions (BCs) for the $SO(N)$ gauge group. Higher-dimensional gauge theories are defined by gauge groups, matter field contents, and the BCs. The numerous patterns of the BCs are classified into the finite equivalence classes, each of which consists of the physically equivalent BCs. In this paper, we reconstruct the canonical forms of the BCs for the $SO(N)$ gauge group through the ``re-orthogonalization method." All the possible equivalent relations between the canonical forms are examined by using the trace conservation laws. The number of the equivalence classes in each orbifold model is obtained.

    ↳ hep-thhep-phPTEP(2025)·0 citations
16. 16*

    Searches for Top-associated Dark Matter Production at the LHC

    Dominic Stafford (for the ATLAS and CMS collaborations)🇩🇪

    Recent searches for dark matter (DM) produced in association with top quarks from the ATLAS and CMS experiments using data collected between 2015 and 2018 are presented. These comprise searches from both experiments for DM in association with a single top quark; an improved ATLAS search for DM in single lepton $t\bar{t}$ final states; an ATLAS search stop squarks decaying to a top quark, a charm quark and neutralinos, and a CMS search for DM produced in association with a pair of top quarks or a single top. These analyses feature novel machine learning and advanced background estimation techniques. No statistically significant excess is observed in any of these searches.

    ↳ hep-exhep-phSciPost Phys.Proc.(2026)·1 citation
17. 17*

    Detecting LHC Neutrinos at Surface Level

    Akitaka Ariga🇨🇭 · Steven Barwick🇺🇸 · Jamie Boyd🇨🇭 · Max Fieg🇺🇸 · Felix Kling🇩🇪 · Toni Mäkelä🇺🇸 · Camille Vendeuvre🇨🇭 · Benjamin Weyer🇨🇭

    The first direct detection of neutrinos at the LHC not only marks the beginning of a novel collider neutrino program at CERN but also motivates considering additional neutrino detectors to fully exploit the associated physics potential. We investigate the feasibility and physics potential of neutrino experiments located at the surface-level. A topographic desk study was performed to identify all points at which the LHC's neutrino beams exit the earth. The closest location lies about 9 km east of the CMS interaction point, at the bottom of Lake Geneva. Several detectors to be placed at this location are considered, including a water Cherenkov detector and an emulsion detector. The detector concepts are introduced, and projections for their contribution to the LHC forward neutrino program and searches for dark sector particles are presented. However, the dilution of the neutrino flux over distance reduces the neutrino yield significantly, limiting the physics potential of surface-level detectors compared to ones closer to the interaction point, including the proposed FPF.

    ↳ hep-exhep-phJHEP(2025)·8 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.