Mon·Dec 11, 2023Monday·December 11, 2023

1. 01*

   Constraints on the trilinear and quartic Higgs couplings from triple Higgs production at the LHC and beyond

   Panagiotis Stylianou🇩🇪 · Georg Weiglein🇩🇪

   Experimental information on the trilinear Higgs boson self-coupling ${\kappa }_3$ and the quartic self-coupling ${\kappa }_4$ will be crucial for gaining insight into the shape of the Higgs potential and the nature of the electroweak phase transition. While Higgs pair production processes provide access to ${\kappa }_3$, triple Higgs production processes, despite their small cross sections, will provide valuable complementary information on ${\kappa }_3$ and first experimental constraints on ${\kappa }_4$. We investigate triple Higgs boson production at the HL-LHC, employing efficient Graph Neural Network methodologies to maximise the statistical yield. We show that it will be possible to establish bounds on the variation of both couplings from the HL-LHC analyses that significantly go beyond the constraints from perturbative unitarity. We also discuss the prospects for the analysis of triple Higgs production at future high-energy lepton colliders operating at the TeV scale.

   hep-phhep-exEPJC(2024)·50 citations
2. 02*

   Positivity from J-Basis Operators in the Standard Model Effective Field Theory

   Chengjie Yang🇨🇳 · Zhe Ren🇨🇳 · Jiang-Hao Yu🇨🇳

   In the effective field theory (EFT), the positivity bound on dim-8 effective operators tells us that the $s^2$ contribution in the scattering amplitude of 2-to-2 process geometrically corresponds to the convex cone composed of the ultraviolet (UV) states as the external rays. The J-Basis method can provide a complete group theory decomposition of the scattering amplitude on the direct product of the gauge group and the Lorentz group, thus to search for all UV states. Compared to previous methods, which can only perform direct product decomposition on the gauge groups, the J-Basis method greatly improves the strictness of the restrictions and also provides a systematic scheme for calculating the positivity bounds of the dim-8 operators.

   hep-phJHEP(2024)·4 citations
3. 03*

   Unified unquenched quark model for heavy-light mesons with chiral dynamics

   Ru-Hui Ni🇨🇳 · Jia-Jun Wu🇨🇳 · Xian-Hui Zhong🇨🇳

   In this work, an unquenched quark model is proposed for describing the heavy-light mesons by taking into account the coupled-channel effects induced by chiral dynamics. After including a relativistic correction term for the strong transition amplitudes, both the mass spectra and decay widths of the observed heavy-light mesons can be successfully described simultaneously in a unified framework, several long-standing puzzles related to the small masses and broad widths are overcome naturally. We also provide valuable guidance in searching new heavy-light mesons by the detailed predictions of their masses, widths, and branching ratios. The success of the unquenched quark model presented in this work indicates it may be an important step for understanding the hadron spectrum.

   hep-phhep-exPRD(2024)·31 citations
4. 04*

   Manifestation of heavy 3/2-spin lepton in large-angle $e^{+}{e}^{-}\to \gamma \gamma$ reaction at high energies

   G. I. Gakh🇺🇦 · M.I.Konchatnij🇺🇦 · N.P.Merenkov🇺🇦 · A.G.Gakh🇺🇦

   Manifestation of the heavy 3/2-spin lepton $(h^{\pm })$, as possible virtual intermediate state in Feynmann diagrams, have been searched in the $e^{+}{e}^{-}\to \gamma \gamma$ reaction at high energies and large photon angles. The spin-vector field ${\Psi }_{\alpha }$ of the 3/2-lepton is described by the Rarita-Schwinger one and phenomenological Lagrangian of $h^{\pm }{e}^{\pm }\gamma$-interaction is chosen similarly to interaction of $\Delta$ isobar with nucleon and $\gamma$ quant. It is described by two constants with dimension $[M^{-1}]$ and $[M^{-2}].$ The differential cross section and polarization asymmetries have been calculated for the case when both beams are polarized longitudinally along their directions, as well transversally, in the reaction plane, and normally, perpendicularly to it. Numerical estimations are performed in wide diapason of the collision energy and parameters entering phenomenological Lagrangian.

   hep-ph0 citations
5. 05*

   Inhomogeneous condensation in the Gross-Neveu model in noninteger spatial dimensions $1\le d<3$. II. Nonzero temperature and chemical potential

   Adrian Koenigstein🇩🇪 · Laurin Pannullo🇩🇪

   We continue previous investigations of the (inhomogeneous) phase structure of the Gross-Neveu model in a noninteger number of spatial dimensions ($1\le d<3$) in the limit of an infinite number of fermion species ($N\to \infty$) at (non)zero chemical potential $\mu$. In this work, we extend the analysis from zero to nonzero temperature $T$. The phase diagram of the Gross-Neveu model in $1\le d<3$ spatial dimensions is well known under the assumption of spatially homogeneous condensation with both a symmetry broken and a symmetric phase present for all spatial dimensions. In $d=1$ one additionally finds an inhomogeneous phase, where the order parameter, the condensate, is varying in space. Similarly, phases of spatially varying condensates are also found in the Gross-Neveu model in $d=2$ and $d=3$, as long as the theory is not fully renormalized, i.e., in the presence of a regulator. For $d=2$, one observes that the inhomogeneous phase vanishes, when the regulator is properly removed (which is not possible for $d=3$ without introducing additional parameters). In the present work, we use the stability analysis of the symmetric phase to study the presence (for $1\le d<2$) and absence (for $2\le d<3$) of these inhomogeneous phases and the related moat regimes in the fully renormalized Gross-Neveu model in the $\mu ,T$-plane. We also discuss the relation between "the number of spatial dimensions" and "studying the model with a finite regulator" as well as the possible consequences for the limit $d\to 3$.

   hep-phcond-mat.str-elhep-thPRD(2024)·19 citations
6. 06*

   New 511 keV line data provides strongest sub-GeV dark matter constraints

   Pedro De la Torre Luque🇸🇪 · Shyam Balaji🇬🇧 · Joseph Silk🇫🇷

   We explore the $511$~keV emission associated to sub-GeV dark matter (DM) particles that can produce electron-positron pairs and form positronium after thermalizing. We use $\sim 16$~yr of SPI data from INTEGRAL to constrain DM properties, considering the full positron propagation and losses, and the free electron density drop away from the Galactic plane. We show that the predicted longitude and latitude profiles vary significantly for different DM masses, unlike previous assumptions, and obtain the strongest limits on sub-GeV DM (from the MeV to a few GeV) so far, excluding cross-sections down to $⟨\sigma v⟩\lesssim 10^{-32}$ cm${}^3$ s${}^{-1}$ for $m_{\chi }\sim 1\text{MeV}$ and $⟨\sigma v⟩\lesssim 10^{-26}$ cm${}^3$ s${}^{-1}$ for $m_{\chi }\sim 5\text{GeV}$ and lifetimes up to $\tau \gtrsim 10^{29}\text{s}(m_{\chi }\sim 1\text{MeV})$ and $\tau \gtrsim 10^{27}\text{s}$ ($m_{\chi }\sim 5$~GeV) for the typical Navarro-Frenk-White DM profile. Our derived limits are robust within a factor of a few due to systematic uncertainties.

   hep-phastro-ph.HEApJL(2024)·43 citations
7. 07*

   Theoretical study of the $B^{+}\to D^{-}{D}_s^{+}{\pi }^{+}$ reaction

   Xuan Luo🇨🇳 · Ruitian Li🇨🇳 · Hao Sun🇨🇳

   Prompted by the recent discoveries of $T_{c\bar{s}0}(2900{)}^{++}$ in the $D_s^{+}{\pi }^{+}$ invariant mass distribution of $B^{+}\to D^{-}{D}_s^{+}{\pi }^{+}$ process, we present a model that hopes to help us investigate the nature of $T_{c\bar{s}0}(2900{)}^{++}$ by reproducing the mass distribution of $D^{-}{\pi }^{+},D_s^{+}{\pi }^{+}$ and $D^{-}{D}_s^{+}$ in $B^{+}\to D^{-}{D}_s^{+}{\pi }^{+}$ decays. The structure of the triangular singularity peak generated from the ${\chi }_{c1}{D}^{\ast +}{K}^{\ast +}$ loop near the $D^{\ast +}{K}^{\ast +}$ threshold is considered in our model may be the experimentally discovered resonance-like state structure $T_{c\bar{s}0}(2900{)}^{++}$. In addition, we employ a coupled-channel approach to describe the dominant contribution of the $D\pi$ $S\text{-wave}$ amplitude, and also consider other excitations. Our model provides a well fit to the invariant mass distributions of $D^{-}{\pi }^{+},D_s^{+}{\pi }^{+}$ and $D^{-}{D}_s^{+}$ simultaneously.

   hep-phhep-exPRD(2024)·1 citation
8. 08*

   Detecting defect dynamics in relativistic field theories far from equilibrium using topological data analysis

   Viktoria Noel🇩🇪 · Daniel Spitz🇩🇪

   We study nonequilibrium dynamics of relativistic $N$-component scalar field theories in Minkowski space-time in a classical-statistical regime, where typical occupation numbers of modes are much larger than unity. In this strongly correlated system far from equilibrium, the role of different phenomena such as nonlinear wave propagation and defect dynamics remains to be clarified. We employ persistent homology to infer topological features of the nonequilibrium many-body system for different numbers of field components $N$ via a hierarchy of cubical complexes. Specifically, we show that the persistent homology of local energy density fluctuations can give rise to signatures of self-similar scaling associated with topological defects, distinct from the scaling behaviour of nonlinear wave modes. This contributes to the systematic understanding of the role of topological defects for far-from-equilibrium time evolutions of nonlinear many-body systems.

   hep-phcond-mat.quant-gashep-latPRD(2024)·10 citations
9. 09*

   Prediction of $P_{cc}$ states in quark model

   Ye Yan🇨🇳 · Hongxia Huang🇨🇳 · Xinmei Zhu🇨🇳 · Jialun Ping🇨🇳

   Inspired by the observation of hidden-charm pentaquark $P_c$ and $P_{cs}$ states by the LHCb Collaboration, we explore the $qqc\bar{c}c$ ($q=u$ or $d$) pentaquark systems in the quark delocalization color screening model. The interaction between baryons and mesons and the influence of channel coupling are studied in this work. Three compact $qqc\bar{c}c$ pentaquark states are obtained, whose masses are 5259 MeV with $I(J^P)$ = $0(1/2^{-})$, 5396 MeV with $I(J^P)$ = $1(1/2^{-})$, and 5465 MeV with $I(J^P)$ = $1(3/2^{-})$. Two molecular states are obtained, which are $I(J^P)$ = $0(1/2^{-})$ ${\Lambda }_{c}J/\psi$ with 5367 MeV and $I(J^P)$ = $0(5/2^{-})$ ${\Xi }_{cc}^{\ast }{\bar{D}}^{\ast }$ with 5690 MeV. These predicted states may provide important information for future experimental search.

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

    Probing ultralight and degenerate dark matter with galactic dynamics

    Diego Blas🇪🇸

    This short contributions summarizes a couple of recent results to test dark matter properties with galactic dynamics. First, I will present the impact in rotation curves from solitonic structures expected at the center of galaxies for ultralight bosonic dark matter. As a result, one can claim that masses of the order $m_{\mathrm{DM}}\lesssim 10^{-21}$eV are in tension with data. Second, I will discuss how the dark matter medium properties change the way a `probe' interacts with the halo. I will focus on dynamical friction and show how it is modified in the case of degenerate fermions. This result may be used to address the Fornax timing problem. I hope that this contribution represents an inspiration to continue exploring other ideas in this direction of using galactic dynamics to tell apart different dark matter models.

    hep-phastro-ph.COastro-ph.GAPoS(2024)·0 citations
11. 11*

    Off-lightcone Wilson-line operators in gradient flow

    Nora Brambilla🇩🇪 · Xiang-Peng Wang🇩🇪

    Off-lightcone Wilson-line operators are constructed using local operators connected by time-like or space-like Wilson lines, which ensure gauge invariance. Off-lightcone Wilson-line operators have broad applications in various contexts. For instance, space-like Wilson-line operators play a crucial role in determining quasi-distribution functions (quasi-PDFs), while time-like Wilson-line operators are essential for understanding quarkonium decay and production within the potential non-relativistic QCD (pNRQCD) framework. In this work, we establish a systematic approach for calculating the matching from the gradient-flow scheme to the $\overline{\mathrm{MS}}$ scheme in the limit of small flow time for off-lightcone Wilson-line operators. By employing the one-dimensional auxiliary-field formalism, we simplify the matching procedure, reducing it to the matching of local current operators. We provide one-loop level matching coefficients for these local current operators. For the case of hadronic matrix element related to the quark quasi-PDFs, we show at one-loop level that the finite flow time effect is very small as long as the flow radius is smaller than the physical distance $z$, which is usually satisfied in lattice gradient flow computations. Applications include lattice gradient flow computations of quark/gluon quasi-PDFs, gluonic correlators related to quarkonium decay and production in pNRQCD, and spin-dependent potentials in terms of chromoelectric and chromomagnetic field insertions into a Wilson loop.

    hep-phhep-latnucl-thJHEP(2024)·20 citations
12. 12*

    Scalar Dark Matter Analysis of 6-Dimensional Effective Field Theory

    Ayşe Kuday🇹🇷 · Ferhat Özok🇹🇷 · Erdinç Ulaş Saka🇹🇷

    We give a prescription how high energy physics tools can be used to perform scalar dark matter analysis. We also present the analysis results of scalar dark matter in the context of 6 dimensional Effective Field Theory.

    hep-phInt.J.Geom.Meth.Mod.Phys.(2024)·0 citations
13. 13*

    Angular and energy distributions of positrons created in subcritical and supercritical slow collisions of heavy nuclei

    N.K. Dulaev🇷🇺 · D.A. Telnov🇷🇺 · V.M. Shabaev🇷🇺 · Y.S. Kozhedub🇷🇺 · I.A. Maltsev🇷🇺 · R.V. Popov🇷🇺 · I.I. Tupitsyn🇷🇺

    Positron creation probabilities as well as energy and angular distributions of outgoing positrons in slow collisions of two identical heavy nuclei are obtained within the two-center approach beyond the monopole approximation. The time-dependent Dirac equation for positron wave functions is solved with the help of the generalized pseudospectral method in modified prolate spheroidal coordinates adapted for variable internuclear separation. Depending on the nuclear charge, the results are obtained for both subcritical and supercritical regimes of the positron creation. The signatures of transition to the supercritical regime in the total positron creation probabilities and energy spectra are discussed. The angular distributions of emitted positrons demonstrate a high degree of isotropy.

    hep-phPRD(2024)·5 citations
14. 14*

    SMEFT analysis of charged lepton flavor violating $B$-meson decays

    Md Isha Ali🇮🇳 · Utpal Chattopadhyay🇮🇳 · N Rajeev🇮🇳 · Joydeep Roy🇮🇳

    Charged lepton flavor violation (cLFV) processes, potentially important for various Beyond the Standard Model Physics scenarios are analyzed in the Standard Model Effective Field Theory (SMEFT) framework. We consider the most relevant 2 quark-2 lepton $(2q2\ell )$ operators for the leptonic and semi-leptonic LFV B-decay (LFVBD) processes $B_s\to {\mu }^{+}{e}^{-},B^{+}\to K^{+}{\mu }^{+}{e}^{-},B^0\to K^{\ast 0}{\mu }^{+}{e}^{-},\mathrm{and}{B}_s\to \varphi {\mu }^{-}{e}^{+}$. We analyse the interplay among the Wilson coefficients responsible for these LFVBDs and other cLFV processes like $\mathrm{CR}(\mu \to \mathrm{e})$, ${\ell }_i\to {\ell }_j\gamma$, ${\ell }_i\to {\ell }_j{\ell }_k{\ell }_m$ and $Z\to {\ell }_i{\ell }_j$, to find the maximal possible LFV effects in $B$-meson decays. We probe the scale of new physics in relation to the constraints imposed by both classes of the LFV decays while considering both the present bounds and future expectations. In view of proposed experiments at LHCb-II and Belle II to study charged LFV processes, we have also provided the upper limits on the indirect constraints on such LFVBDs. For the processes where $B$ meson is decaying to ${\mu }^{\pm }$ and $e^{\mp }$, we show that new physics can be constrained by an enhancement of 2-4 orders of magnitude on the current sensitivities of the BRs of $B^{+}\to K^{+}{\mu }^{+}{e}^{-},B^0\to K^{\ast 0}{\mu }^{+}{e}^{-}\mathrm{and}{B}_s\to \varphi {\mu }^{\pm }{e}^{\mp }$.

    hep-phPRD(2024)·15 citations
15. 15*

    Troubles mounting for multipolar dark matter

    Debajit Bose🇮🇳 · Debtosh Chowdhury🇮🇳 · Poulami Mondal🇮🇳 · Tirtha Sankar Ray🇮🇳

    In this paper, we revisit the experimental constraints on the multipolar dark matter that has derivative coupling to the visible sector mediated by the Standard Model photon. The momentum dependent interaction enables them to be captured efficiently within massive celestial bodies boosted by their steep gravitational potential. This phenomena makes compact celestial bodies as an efficient target to probe such type of dark matter candidates. We demonstrate that a synergy of the updated direct detection results from DarkSide-50 and LUX-ZEPLIN together with IceCube bounds on high energy solar neutrinos from dark matter capture disfavour the viable parameter space of the dipolar dark matter scenario. Whereas, for the anapole dark matter scenario, a narrow window survives that lies within the reach of prospective heating signals due to the capture of dark matter at cold neutron stars.

    hep-phastro-ph.COastro-ph.HEhep-exJHEP(2024)·18 citations
16. 16*

    Inclusive semileptonic $B_s^0$ meson decays at the LHC via a sum-of-exclusive modes technique: possibilities and prospects

    Michel De Cian🇩🇪 · Natalia Feliks🇨🇭 · Marcello Rotondo🇮🇹 · K. Keri Vos🇳🇱

    We propose an approach for measuring the moments of the hadronic invariant mass distribution in semileptonic $B_s^0$ meson decays using a sum-of-exclusive technique. Using the present and foreseen knowledge about exclusive semileptonic $B_s^0$ decays, we estimate the uncertainties on moments of the kinematic distribution. Semileptonic $B_s^0$ decays can be described, as their $B^0$ counterpart, using the Heavy Quark Expansion (HQE), with the only difference between the $B_s^0$ and $B^0$ mesons being the $SU(3{)}_F$ breaking effects that change the numerical values of the non-perturbative HQE parameters. We extract the HQE parameters for the $B_s^0$ decays from our estimates of the moments, showing the potential of the proposed method. We identify a set of required measurements for a future precision measurement.

    hep-phhep-exJHEP(2024)·6 citations
17. 17*

    Evolution and fluctuations of chiral chemical potential in heavy ion collisions

    Vladimir Kovalenko🇷🇺

    The possible appearance of the effects of local parity breaking in the QCD medium formed in heavy ion collisions due to violation of chiral symmetry can be quantified by corresponding chiral chemical potential ${\mu }_5$. The experimental observables sensitive to the effects of local parity violation in strong interaction include search for polarisation splitting of the ${\rho }_0$ and ${\omega }_0$ mesons via angular dependence of spectral functions in their decay to leptons. In this paper we study the space-time evolution and fluctuations of ${\mu }_5$ using relativistic hydrodynamics and estimate their effect on the light vector meson polarization splitting in Pb-Pb collisions at LHC energy.

    hep-phnucl-exIJMPE(2024)·2 citations
18. 18*

    Unveiling new physics with discoveries at Intensity Frontier

    Oleksii Mikulenko🇳🇱 · Kyrylo Bondarenko🇸🇪 · Alexey Boyarsky🇳🇱 · Oleg Ruchayskiy🇩🇰

    The idea of feebly interacting particles (FIPs) has emerged as an important approach to address challenges beyond the Standard Model. The next generation of Intensity Frontier experiments is set to explore these particles in greater depth. While many experiments may detect FIP signals in unexplored regions of masses and couplings, interpretation of the properties of particles behind these signals is typically neglected. In this paper, we present a novel framework designed to systematically determine the models behind a potential signal. Our approach allows us to assess the scientific reach of experiments beyond the concept of sensitivity to the smallest coupling constant leading to a detectable signal. We clarify the potential impact such signals could have on particle physics models. This paper is complemented by a Python package for the presented framework, available at omikulen/modeltesting.

    hep-ph10 citations
19. 19*

    Herwig 7.3 Release Note

    Gavin Bewick🇬🇧 · Silvia Ferrario Ravasio🇨🇭 · Stefan Gieseke🇩🇪 · Stefan Kiebacher🇩🇪 · Mohammad R. Masouminia🇬🇧 · Andreas Papaefstathiou🇺🇸 · Simon Plätzer🇦🇹 · Peter Richardson🇬🇧 · Daniel Samitz🇦🇹 · Michael H. Seymour🇬🇧 · Andrzej Siódmok🇵🇱 · James Whitehead🇵🇱

    A new release of the Monte Carlo event generator Herwig (version 7.3) has been launched. This iteration encompasses several enhancements over its predecessor, version 7.2. Noteworthy upgrades include: the implementation of a process-independent electroweak angular-ordered parton shower integrated with QCD and QED radiation; a new recoil scheme for initial-state radiation improving the behaviour of the angular-ordered parton shower; the incorporation of the heavy quark effective theory to refine the hadronization and decay of excited heavy mesons and heavy baryons; a dynamic strategy to regulate the kinematic threshold of cluster splittings within the cluster hadronization model; several improvements to the structure of the cluster hadronization model allowing for refined models; the possibility to extract event-by-event hadronization corrections in a well-defined way; the possibility of using the string model, with a dedicated tune. Additionally, a new tuning of the parton shower and hadronization parameters has been executed. This article discusses the novel features introduced in version 7.3.0.

    hep-phEPJC(2024)·103 citations
20. 20*

    Gravitational $p\to {\Delta }^{+}$ transition form factors in chiral perturbation theory

    H. Alharazin🇩🇪 · B.-D. Sun🇩🇪 · E. Epelbaum🇩🇪 · J. Gegelia🇩🇪 · U.-G. Meißner🇩🇪

    The gravitational form factors of the transition from the proton to the ${\Delta }^{+}$ resonance are calculated to leading one-loop order using a manifestly Lorentz-invariant formulation of chiral perturbation theory. We take into account the leading electromagnetic and strong isospin-violating effects. The loop contributions to the transition form factors are found to be free of power-counting violating pieces, which is consistent with the absence of tree-level diagrams at the considered order. In this sense, our results can be regarded as predictions of chiral perturbation theory.

    hep-phnucl-thJHEP(2024)·22 citations
21. 21*

    Non-Relativistic Quantum Chromodynamics in Parton Showers

    Naomi Cooke🇬🇧 · Philip Ilten🇺🇸 · Leif Lönnblad🇸🇪 · Stephen Mrenna🇺🇸

    Measurements of quarkonia isolation in jets at the Large Hadron Collider (LHC) have been shown to disagree with fixed-order non-relativistic quantum chromodynamics (NRQCD) calculations, even at higher orders. Calculations using the fragmenting jet function formalism are able to better describe data but cannot provide full event-level predictions. In this work we provide an alternative model via NRQCD production of quarkonia in a timelike parton shower. We include this model in the Pythia 8 event generator and validate our parton-shower implementation against analytic forms of the relevant fragmentation functions. Finally, we make inclusive predictions of quarkonia production for the decay of the standard-model Higgs boson.

    hep-phEPJC(2024)·18 citations
22. 22*

    Anomalous Dimensions via on-shell Methods: Operator Mixing and Leading Mass Effects

    L.C. Bresciani🇮🇹 · G. Levati🇮🇹 · P. Mastrolia🇮🇹 · P. Paradisi🇮🇹

    We elaborate on the application of on-shell and unitarity-based methods for evaluating renormalization group coefficients, and generalize this framework to account for the mixing of operators with different dimensions and leading mass effects. We derive a master formula for anomalous dimensions stemming from the general structure of operator mixings, up to two-loop order, and show how the Higgs low-energy theorem can be exploited to include leading mass effects. A few applications on the renormalization properties of popular effective field theories showcase the strength of the proposed approach, which drastically reduces the complexity of standard loop calculations. Our results provide a powerful tool to interpret experimental measurements of low-energy observables, such as flavor violating processes or electric and magnetic dipole moments, as induced by new physics emerging above the electroweak scale.

    hep-phhep-thPRD(2024)·17 citations
23. 23*

    Discriminating Majorana and Dirac heavy neutrinos at lepton colliders

    Krzysztof Mękała🇩🇪 · Jürgen Reuter🇩🇪 · Aleksander Filip Żarnecki🇵🇱

    In this paper we investigate how well the nature of heavy neutral leptons can be determined at a future lepton collider, after its potential discovery. Considered in a simplified model are prompt decays of the neutrino in the mass range from 100 GeV to 10 TeV. We study event selection and application of multivariate analyses to determine whether such a newly discovered particle is of the Dirac or Majorana nature. Combining lepton charge and kinematic event variables, we find that the nature of a heavy neutrino, whether it is a Dirac or a Majorana particle, can be determined at 95% C.L. almost in the whole discovery range. We will briefly speculate about other than the studied channels and the robustness of this statement in more general models of heavy neutral leptons, particularly on the complementarity of high-energy electron-positron vs. muon colliders on resolving the flavor structure of heavy neutrinos.

    hep-phJHEP(2024)·15 citations
24. 24*

    The Higgs-gluon form factor at three loops in QCD with three mass scales

    Marco Niggetiedt🇩🇪 · Johann Usovitsch🇨🇭

    We report on the complete three-loop corrections to the Higgs-gluon form factor in QCD. While previous calculations are based on QCD with a single heavy quark of arbitrary mass, we extend the study to QCD involving two different massive quark flavors. Thereby, the full set of possible Feynman diagrams at three-loop order is taken into account. Employing differential equations for the relevant master integrals, we determine the form factor in terms of analytic expansions. Outside the radii of convergence, we compute high-precision numerical samples over the two-dimensional physical parameter space. Our new findings will enter as virtual corrections the computation of the top-bottom interference in hadronic Higgs-boson production at next-to-next-to-leading order (NNLO) in QCD.

    hep-phJHEP(2024)·11 citations
25. 25*

    Understanding oscillating features of the timelike nucleon electromagnetic form factors within the extending vector meson dominance model

    Bing Yan🇨🇳 · Cheng Chen🇨🇳 · Xia Li🇨🇳 · Ju-Jun Xie🇨🇳

    We investigate the nonmonotonic behavior observed in the time-like nucleon electromagnetic form factors. Using a phenomenological extending vector meson dominance model, where the ground states $\rho$ and $\omega$ and their excited states $\rho (2D)$, $\omega (3D)$, and $\omega (5S)$ are taken into account, we have successfully reproduced the cross sections of $e^{+}{e}^{-}\to p\bar{p}$ and $e^{+}{e}^{-}\to n\bar{n}$ reactions. Furthermore, we have derived the nucleon electromagnetic form factors in the time-like region, and it is found that the so-called periodic behaviour of the nucleon effective form factors is not confirmed. However, there are indeed nonmonotonic structures in the line shape of nucleon effective form factors, which can be naturally reproduced by considering the contributions from the low-lying excited vector states.

    ↳ nucl-thhep-exhep-phnucl-exPRD(2024)·12 citations
26. 26*

    Classifying large N limits of multiscalar theories by algebra

    Nadia Flodgren🇸🇪 · Bo Sundborg🇸🇪

    We develop a new approach to RG flows and show that one-loop flows in multiscalar theories can be described by commutative but non-associative algebras. As an example related to $D$-brane field theories and tensor models, we study the algebra of a theory with $M$ $SU(N)$ adjoint scalars and its large $N$ limits. The algebraic concepts of idempotents and Peirce numbers/Kowalevski exponents are used to characterise the RG flows. We classify and describe all large $N$ limits of algebras of multiadjoint scalar models: the standard `t Hooft matrix theory limit, a `multi-matrix' limit, each with one free parameter, and an intermediate case with extra symmetry and no free parameter of the algebra, but an emergent free parameter from a line of one-loop fixed points. The algebra identifies these limits without diagrammatic or combinatorial analysis.

    ↳ hep-thhep-phJHEP(2024)·4 citations
27. 27*

    Role of initial transverse momentum in a hybrid approach

    Niklas Götz🇩🇪 · Lucas Constantin🇩🇪 · Hannah Elfner🇩🇪

    The purpose of this work is to study the effect of exchanging initial condition models in a modular hybrid approach. The focus lies on the event-by-event correlations of elliptic and triangular flow. This study is performed in the hybrid approach SMASH-vHLLE, composed of the hadronic transport approach SMASH and the (3+1)d viscous hydrodynamic code vHLLE. The initial condition models investigated are SMASH IC, Trento and IP-Glasma. Correlations are calculated on an event-by-event basis between the eccentricities and momentum anisotropies of the initial state as well as the momentum anisotropies in the final state, both for ultra-central and off-central collisions for AuAu collisions at $\sqrt{s_{NN}}=200$ GeV. This work demonstrates that, although averaged values for the eccentricities of these models are very similar, substantial differences exist both in the distributions of eccentricities, the correlations amongst the initial state properties as well as in the correlations between initial state and final state properties. Notably, whereas initial state momentum anisotropy is shown to not affect the final state flow, the presence of radial flow affects the emergence of final state momentum anisotropies. Inclusion of radial flow in the linear fit improves the prediction of final state flow from initial state properties. The presence of momentum in the initial state has an effect on the emergence of flow and is therefore a relevant part of initial state models, challenging the common understanding of final state momentum anisotropies being a linear response to initial state eccentricity only.

    ↳ nucl-thhep-phnucl-exPRC(2024)·5 citations
28. 28*

    Two-fermion negativity and confinement in the Schwinger model

    Adrien Florio🇺🇸

    We consider the fermionic (logarithmic) negativity between two fermionic modes in the Schwinger model. Recent results pointed out that fermionic systems can exhibit stronger entanglement than bosonic systems, exhibiting a negativity that decays only algebraically. The Schwinger model is described by fermionic excitations at short distances, while its asymptotic spectrum is the one of a bosonic theory. We show that the two-mode negativity detects this confining, fermion-to-boson transition, shifting from an algebraic decay to an exponential decay at distances of the order of the de Broglie wavelength of the first excited state. We derive analytical expressions in the massless Schwinger model and confront them with tensor network simulations. We also perform tensor network simulations in the massive model, which is not solvable analytically, and close to the Ising quantum critical point of the Schwinger model, where we show that the negativity behaves as its bosonic counterpart.

    ↳ hep-thcond-mat.str-elhep-lathep-ph+1PRD(2024)·22 citations

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