Mon·Aug 12, 2024Monday·August 12, 2024

1. 01*

   One Born$-$Oppenheimer Effective Theory to rule them all: hybrids, tetraquarks, pentaquarks, doubly heavy baryons and quarkonium

   Matthias Berwein🇩🇪 · Nora Brambilla🇩🇪 · Abhishek Mohapatra🇩🇪 · Antonio Vairo🇩🇪

   The discovery of XYZ exotic states in the hadronic sector with two heavy quarks, represents a significant challenge in particle theory. Understanding and predicting their nature remains an open problem. In this work, we demonstrate how the Born$-$Oppenheimer (BO) effective field theory (BOEFT), derived from Quantum Chromodynamics (QCD) on the basis of scale separation and symmetries, can address XYZ exotics of any composition. We derive the Schrödinger coupled equations that describe hybrids, tetraquarks, pentaquarks, doubly heavy baryons, and quarkonia at leading order, incorporating nonadiabatic terms, and present the predicted multiples. We define the static potentials in terms of the QCD static energies for all relevant cases. We provide the precise form of the nonperturbative low-energy gauge-invariant correlators required for the BOEFT: static energies, generalized Wilson loops, gluelumps, and adjoint mesons. These are to be calculated on the lattice and we calculate here their short-distance behavior. Furthermore, we outline how spin-dependent corrections and mixing terms can be incorporated using matching computations. Lastly, we discuss how static energies with the same BO quantum numbers mix at large distances leading to the phenomenon of avoided level crossing. This effect is crucial to understand the emergence of exotics with molecular characteristics, such as the ${\chi }_{c1}(3872)$. With BOEFT both the tetraquark and the molecular picture appear as part of the same description.

   hep-phhep-exhep-latPRD(2024)·74 citations
2. 02*

   Some remarks on Coulombic effects in $pp$ and $\bar{p}p$ scattering and the determination of $\rho$

   Loyal Durand🇺🇸 · Phuoc Ha🇺🇸

   We point out a very simple method for calculating the mixed Coulomb-nuclear corrections to the $pp$ and $\bar{p}p$ scattering amplitudes that has been missed in the extensive past work on this problem. The method expresses the correction in terms of a rapidly convergent integral involving the inverse Fourier-Bessel transform of the nuclear amplitude and a known factor containing the Coulomb phase shift with form-factor corrections. The transform can be calculated analytically for the exponential-type model nuclear amplitudes commonly used in fits to the high-energy data at small momentum transfers, and gives very accurate results for the corrections. We examine the possible effects of the Martin zero in the real part of the nuclear amplitude, and the accuracy of the Bethe-West-Yennie phase approximation for the Coulomb-nuclear corrections. We then apply the method to a redetermination of the ratio $\rho$ of the real to the imaginary parts of the forward scattering amplitude in fits to high-energy ISR data previously analyzed using an approximate version of the correction. The only significant changes relative the accuracy of those fits are at 52.8 GeV. Our method is applicable more generally, and can be used also at lower energies and for proton-nucleus scattering.

   hep-phnucl-thPRD(2024)·0 citations
3. 03*

   Ultralight axion and modern cosmology tensions

   Takeshi Fukuyama🇯🇵

   String-inspired axion model is considered to comprehensively solve the problems of modern cosmology, Hubble tension problem, the origin of the stochastic gravitational wave background, and too early formation of supermassive black holes at high $z$.

   hep-phastro-ph.COgr-qcInt.J.Mod.Phys.A(2025)·2 citations
4. 04*

   Charmonium-like states with the exotic quantum number $J^{PC}=3^{-+}$

   Hong-Zhou Xi🇨🇳 · Hua-Xing Chen🇨🇳 · Wei Chen🇨🇳 · T. G. Steele🇨🇦 · Yong Zhang🇨🇳 · Dan Zhou🇨🇳

   We apply the method of QCD sum rules to study the $qc\bar{q}\bar{c}$ tetraquark states with the exotic quantum number $J^{PC}=3^{-+}$, and extract the mass of the lowest-lying state to be $4.49_{-0.41}^{+0.45}$ GeV. To construct the relevant tetraquark currents we need to explicitly add the covariant derivative operator. Our systematic analysis of these interpolating currents indicates that: a) this state readily decays into the $P$-wave $[\rho J/\psi ]/[\omega J/\psi ]$ channel but not into the $[\rho {\chi }_{c2}]/[\omega {\chi }_{c2}]/[J/\psi f_2(1270)]$ channels, and b) it readily decays into the $[D^{\ast }{\bar{D}}_2^{\ast }]$ channel but not into the $P$-wave $[D^{\ast }{\bar{D}}^{\ast }]$ channel.

   hep-phhep-exPRD(2024)·1 citation
5. 05*

   Low-Energy Supernova Constraints on Millicharged Particles

   Changqian Li🇨🇳 · Zuowei Liu🇨🇳 · Wenxi Lu🇨🇳 · Zicheng Ye🇨🇳

   The hot and dense conditions of the supernova core provide an ideal environment for the production of new feebly-interacting particles. Low-energy supernovae, characterized by low explosion energy, are particularly intriguing due to their stringent constraints on energy transfer from the core to the mantle by new particles. We investigate low-energy supernova constraints on millicharged particles by considering three production channels in the core: plasmon decay, proton bremsstrahlung, and electron-positron annihilation. We compute the energy deposition due to Coulomb scatterings of millicharged particles with protons in the mantle and find that low-energy supernovae impose the most stringent constraints on millicharged particles in the mass range of $\sim (12-170)$ MeV. Furthermore, we find that the electron-positron annihilation process, previously omitted in supernova studies on millicharged particles, is the dominant production channel in the high-mass region. This leads to new constraints from both supernova cooling calculations and low-energy supernova analyses. We also investigate MCP production via processes involving thermal pions and find that these processes could dominate over electron-positron annihilation, albeit with significant uncertainties.

   hep-phastro-ph.COastro-ph.HEJHEP(2025)·8 citations
6. 06*

   Entanglement and Bell inequality violation in $B\to \Phi \Phi$ decays

   Emidio Gabrielli🇮🇹 · Luca Marzola🇪🇪

   The decays of the $B$ meson into vector mesons, observed at the LHCb experiment, provide an ideal laboratory to investigate particle physics phenomena with quantum information theory methods. In this article, we focus on the decays yielding a pair of $\Phi$ mesons to investigate the presence of entanglement in the spin correlations of the system and quantify the amount of Bell inequality violation it entails. Our results show that the present LHCb data allows access to entanglement and to the Bell inequality violation with a significance exceeding the 5$\sigma$ threshold in both the cases. This demonstrates that the strong and electroweak interactions responsible for the $B$ meson decay act as a source of entanglement and the quantum mechanics nature of high-energy phenomena. Particular attention is paid to the assessment of loopholes: deficiencies in the experimental setup which could invalidate the results of the Bell test.

   hep-phhep-exquant-phSymmetry(2024)·29 citations
7. 07*

   Tensor Reduction for Feynman Integrals with Lorentz and Spinor Indices

   Jae Goode🇬🇧 · Franz Herzog🇬🇧 · Anthony Kennedy🇬🇧 · Sam Teale🇬🇧 · Jos Vermaseren🇳🇱

   We present an efficient graphical approach to construct projectors for the tensor reduction of multi-loop Feynman integrals with both Lorentz and spinor indices in $D$ dimensions. An ansatz for the projectors is constructed making use of its symmetry properties via an orbit partition formula. The graphical approach allows to identify and enumerate the orbits in each case. For the case without spinor indices we find a 1 to 1 correspondence between orbits and integer partitions describing the cycle structure of certain bi-chord graphs. This leads to compact combinatorial formulae for the projector ansatz. With spinor indices the graph-structure becomes more involved, but the method is equally applicable. Our spinor reduction formulae are based on the antisymmetric basis of $\gamma$ matrices, and make use of their orthogonality property. We also provide a new compact formula to pass into the antisymmetric basis. We compute projectors for vacuum tensor Feynman integrals with up to 32 Lorentz indices and up to 4 spinor indices. We discuss how to employ the projectors in problems with external momenta.

   hep-phhep-thJHEP(2024)·16 citations
8. 08*

   Model-independent predictions for decays of double-heavy hadrons into pairs of heavy hadrons

   R. Bruschini🇺🇸

   Double-heavy hadrons can decay into pairs of heavy hadrons through transitions from confining Born-Oppenheimer potentials to heavy-hadron-pair potentials with the same Born-Oppenheimer quantum numbers. The states of the double-heavy hadron are constrained by a Born-Oppenheimer exclusion principle from the identical heavy quarks. The states of a pair of identical heavy hadrons are constrained by exclusion principles from identical particles. The transitions are also constrained by conservation of angular momentum and parity. From these constraints, we derive model-independent selection rules for decays of double-heavy hadrons into pairs of heavy hadrons. The coupling potentials are expressed as sums of products of Born-Oppenheimer transition amplitudes and angular-momentum coefficients. If there is a single dominant Born-Oppenheimer transition amplitude, it factors out of the coupling potentials between double-heavy hadrons in the same Born-Oppenheimer multiplet and pairs of heavy hadrons in specific heavy-quark-spin-symmetry multiplets and out of the corresponding partial decay rates. As examples, we discuss the Born-Oppenheimer potentials and multiplets for conventional double-heavy baryons and for double-heavy tetraquark mesons. We also discuss the relative partial decay rates for conventional double-heavy baryons into pairs of heavy hadrons.

   hep-phPRD(2024)·6 citations
9. 09*

   Gravitational Waves and Dark Matter in the Gauged Two-Higgs Doublet Model

   Michael J. Ramsey-Musolf🇨🇳 · Van Que Tran🇨🇳 · Tzu-Chiang Yuan🇹🇼

   We investigate the possibility of a strong first-order electroweak phase transition during the early universe within the framework of the gauged two-Higgs doublet model (G2HDM) and explore its detectability through stochastic gravitational wave signals. The G2HDM introduces a dark replica of the Standard Model electroweak gauge group, inducing an accidental $Z_2$ symmetry which not only leads to a simple scalar potential at tree-level but also offers a compelling vectorial dark matter candidate. Using the high temperature expansion in the effective potential that manifests gauge invariance, we find a possible two-step phase transition pattern in the model with a strong first-order transition occurring in the second step at the electroweak scale temperature. Collider data from the LHC plays a crucial role in constraining the parameter space conducive to this two-step transition. Furthermore, satisfying the nucleation condition necessitates the masses of scalar bosons in the hidden sector to align with the electroweak scale, potentially probed by future collider detectors. The stochastic gravitational wave energy spectrum associated with the phase transition is computed. The results indicate that forthcoming detectors such as BBO, LISA, DECIGO, TianQin and Taiji could potentially detect the gravitational wave signals generated by the first-order phase transition. Additionally, we find that the parameter space probed by gravitational waves can also be searched for in future dark matter direct detection experiments, in particular those designed for dark matter masses in the sub-GeV range using the superfluid Helium target detectors.

   hep-phJHEP(2025)·15 citations
10. 10*

    Projection-to-Born-improved Subtractions at NNLO

    John Campbell🇺🇸 · Tobias Neumann🇺🇸 · Gherardo Vita🇨🇭

    While the current frontier in fixed-order precision for collider observables is N${}^3$LO, important steps are necessary to consolidate NNLO cross-section predictions with improved stability and efficiency. Slicing methods have been successfully applied to obtain NNLO and N${}^3$LO predictions, but have shown poor performance in the presence of fiducial cuts due to large kinematical power corrections. In this paper we implement Projection-to-Born-improved $q_T$ (P2B $q_T$) and jettiness (P2B ${\tau }_0$) subtractions for a large class of color singlet processes in MCFM. This method allows for the efficient evaluation of \emph{fiducial} power corrections in any non-local subtraction scheme using a Projection-to-Born subtraction. We demonstrate the significant numerical improvements of this method based on fiducial Drell-Yan and Higgs cross-sections. Moreover, with fiducial power corrections removed via this method, the leading-logarithmic power corrections that have only been calculated without fiducial cuts can be included, further improving the calculations. For di-photon production with photon isolation, we devise a novel method in combination with P2B-improved subtractions, which we name $P2B_{\gamma }$ ${\tau }_0$, and $P2B_{\gamma }$ $q_T$ for the two subtraction schemes, respectively. This method allows the inclusion of both fiducial power corrections due to kinematic cuts on the photons and a set of isolation power corrections in the fragmentation channel where a quark may enter the isolation cone. We find significant improvements in the convergence of NNLO di-photon cross-sections with photon isolation cuts, demonstrating that it is possible to achieve a stable and efficient calculation of di-photon cross-sections using slicing methods.

    hep-phhep-exJHEP(2025)·9 citations
11. 11*

    General Quartic $\beta$-Function at Three Loops

    Tom Steudtner🇩🇪 · Anders Eller Thomsen🇨🇭

    We determine the three-loop $\overline{\text{MS}}$ quartic $\beta$-function for the most general renormalisable four-dimensional theories. A general parametrization of the $\beta$-function is compared to known $\beta$-functions for specific theories to fix all coefficients. Three-loop $\beta$-functions for the cubic coupling and scalar mass terms also follow from the result, which is made available in software packages.

    hep-phJHEP(2024)·19 citations
12. 12*

    Learning the Simplicity of Scattering Amplitudes

    Clifford Cheung🇺🇸 · Aurélien Dersy🇺🇸 · Matthew D. Schwartz🇺🇸

    The simplification and reorganization of complex expressions lies at the core of scientific progress, particularly in theoretical high-energy physics. This work explores the application of machine learning to a particular facet of this challenge: the task of simplifying scattering amplitudes expressed in terms of spinor-helicity variables. We demonstrate that an encoder-decoder transformer architecture achieves impressive simplification capabilities for expressions composed of handfuls of terms. Lengthier expressions are implemented in an additional embedding network, trained using contrastive learning, which isolates subexpressions that are more likely to simplify. The resulting framework is capable of reducing expressions with hundreds of terms - a regular occurrence in quantum field theory calculations - to vastly simpler equivalent expressions. Starting from lengthy input expressions, our networks can generate the Parke-Taylor formula for five-point gluon scattering, as well as new compact expressions for five-point amplitudes involving scalars and gravitons. An interactive demonstration can be found at https://spinorhelicity.streamlit.app .

    ↳ hep-thcs.LGhep-phSciPost Phys.(2025)·18 citations
13. 13*

    New Structures in the $J/\psi$ $J/\psi$ Mass Spectrum at CMS

    Xining Wang🇨🇳 · Kai Yi🇨🇳

    A search is reported for structures near the $J/\psi$ $J/\psi$ mass threshold using a dataset of proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$ recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of about $135\mathrm{f}{\mathrm{b}}^{-1}$. Two structures are observed with a significance exceeding $5\sigma$ and evidence of an additional structure is reported with a local significance of $4.7\sigma$.

    ↳ hep-exhep-phEPJ Web Conf.(2024)·2 citations
14. 14*

    Extracting Signal Electron Trajectories in the COMET Phase-I Cylindrical Drift Chamber Using Deep Learning

    Fumihiro Kaneko🇯🇵 · Yoshitaka Kuno🇯🇵 · Joe Sato🇯🇵 · Ikuya Sato🇯🇵 · Dorian Pieters🇯🇵 · Chen Wu🇯🇵

    We present a pioneering approach to tracking analysis within the COMET Phase-I experiment, which aims to search for the charged lepton flavor violating $\mu \to e$ conversion process in a muonic atom, at J-PARC, Japan. This paper specifically introduces the extraction of signal electron trajectories in the COMET Phase-I cylindrical drift chamber (CDC) amidst a high background hit rate, with more than $40\%$ occupancy of the total CDC cells, utilizing deep learning techniques of semantic segmentation. Our model achieved remarkable results, with a purity rate of $98\%$ and a retention rate of $90\%$ for CDC cells with signal hits, surpassing the design-goal performance of $90\%$ for both metrics. This study marks the initial application of deep learning to COMET tracking, paving the way for more advanced techniques in future research.

    ↳ hep-exhep-phPTEP(2025)·2 citations
15. 15*

    Sound Speed Resonance of Gravitational Waves in Gauss-Bonnet-coupled inflation

    Andrea Addazi🇨🇳 · Yermek Aldabergenov🇨🇳 · Yifu Cai🇨🇳

    We demonstrate the occurrence of Sound Speed Resonances (SSR) in Gauss-Bonnet-coupled inflation across a wide range of coupling functions and parameters. After inflation, the damped oscillations of the inflaton around its potential minimum induces damped oscillations of the sound speed of tensor modes, leading to resonant amplification of the latter. Once the inflaton stabilizes around the minimum, the tensor sound speed reduces to unity (speed of light). In the context of multi-field inflation, the sound speed oscillations can be followed by a second phase of inflation, resulting in a distinctive stochastic background of Gravitational Waves (GWs). We show that these GW signals can be probed by upcoming experiments such as $\text{SKA}$, $\text{DECIGO}$, and $\text{BBO}$ depending on the duration of the second inflationary phase.

    ↳ gr-qchep-phhep-thPRD(2024)·7 citations
16. 16*

    On the electron self-energy to three loops in QED

    Claude Duhr🇩🇪 · Federico Gasparotto🇩🇪 · Christoph Nega🇩🇪 · Lorenzo Tancredi🇩🇪 · Stefan Weinzierl🇩🇪

    We compute the electron self-energy in Quantum Electrodynamics to three loops in terms of iterated integrals over kernels of elliptic type. We make use of the differential equations method, augmented by an $ϵ$-factorized basis, which allows us to gain full control over the differential forms appearing in the iterated integrals to all orders in the dimensional regulator. We obtain compact analytic expressions, for which we provide generalized series expansion representations that allow us to evaluate the result numerically for all values of the electron momentum squared. As a by product, we also obtain $ϵ$-resummed results for the self-energy in the on-shell limit $p^2=m^2$, which we use to recompute the known three-loop renormalization constants in the on-shell scheme.

    ↳ hep-thhep-phJHEP(2024)·43 citations
17. 17*

    Galactic Gas Models Strongly Affect the Determination of the Diffusive Halo Height

    Pedro De La Torre Luque🇪🇸 · Tim Linden🇸🇪

    The height of the Milky Way diffusion halo, above which cosmic-rays can freely escape the galaxy, is among the most critical, yet poorly known, parameters in cosmic-ray physics. Measurements of radioactive secondaries, such as ${}^{10}$Be or ${}^{26}$Al, which decay equivalently throughout the diffusive volume, are expected to provide the strongest constraints. This has motivated significant observational work to constrain their isotopic ratios, along with theoretical work to constrain the cross-section uncertainties that are thought to dominate radioactive secondary fluxes. In this work, we show that the imprecise modelling of the Milky Way spiral arms significantly affects our ability to translate ${}^{10}$Be and ${}^{26}$Al fluxes into constraints on the diffusive halo height, biasing our current results. Utilizing state-of-the-art spiral arms models we produce new predictions for the ${}^{10}$Be and ${}^{26}$Al fluxes that motivate upcoming measurements by AMS-02 and HELIX.

    ↳ astro-ph.GAastro-ph.HEhep-phJCAP(2025)·8 citations
18. 18*

    Two-Loop Five-Point Two-Mass Planar Integrals and Double Lagrangian Insertions in a Wilson Loop

    Samuel Abreu🇨🇭 · Dmitry Chicherin🇫🇷 · Vasily Sotnikov🇨🇭 · Simone Zoia🇨🇭

    We consider the complete set of planar two-loop five-point Feynman integrals with two off-shell external legs. These integrals are relevant, for instance, for the calculation of the second-order QCD corrections to the production of two heavy vector bosons in association with a jet or a photon at a hadron collider. We construct pure bases for these integrals and reconstruct their analytic differential equations in canonical form through numerical sampling over finite fields. The newly identified symbol alphabet, one of the most complex to date, provides valuable data for bootstrap methods. We then apply our results to initiate the study of double Lagrangian insertions in a four-cusp Wilson loop in planar maximally supersymmetric Yang-Mills theory, computing it through two loops. We observe that it is finite, conformally invariant in four dimensions, and of uniform transcendentality. Furthermore, we provide numerical evidence for its positivity within the amplituhedron region through two loops.

    ↳ hep-thhep-phJHEP(2024)·29 citations
19. 19*

    $SL(2,\mathbb{Z})$ Cosmological Attractors

    Renata Kallosh🇺🇸 · Andrei Linde🇺🇸

    We study cosmological theory where the kinetic term and potential have $SL(2,\mathbb{Z})$ symmetry. Potentials have a plateau at large values of the inflaton field, where the axion forms a flat direction. Due to the underlying hyperbolic geometry and special features of $SL(2,\mathbb{Z})$ potentials, the theory exhibits an $\alpha$-attractor behavior: its cosmological predictions are stable with respect to significant modifications of the $SL(2,\mathbb{Z})$ invariant potentials. We present a supersymmetric version of this theory in the framework of $\overline{D3}$ induced geometric inflation. The choice of $\alpha$ is determined by underlying string compactification. For example, in a CY compactification with $T^2$, one has $3\alpha =1$, the lowest discrete Poincaré disk target for LiteBIRD

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2025)·35 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.