Fri·Jul 12, 2024Friday·July 12, 2024

1. 01*

   Description of the processes $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ and ${\tau }^{-}\to {\pi }^{-}{\pi }^0{\nu }_{\tau }$ in the NJL model with value of the vector coupling constant $g_{\rho }=6$

   M.K. Volkov🇷🇺 · A.A. Pivovarov🇷🇺 · K. Nurlan🇷🇺

   It is shown that the processes $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ and ${\tau }^{-}\to {\pi }^{-}{\pi }^0{\nu }_{\tau }$ can be described in a unified approach in satisfactory agreement with experiment using the vector coupling constant $g_{\rho }=6$. In this case, in addition to quark loops, it is also necessary to take into account meson loops corresponding to the next order in $1/N_c$. These loops must be taken into account when describing the $\gamma (W)\to \rho$ transition, as well as in interaction of mesons in the final state.

   hep-phNPA(2025)·1 citation
2. 02*

   Leptophilic ALPs with TWIST data for polarized muon decays

   Ankita Budhraja🇳🇱 · Samadrita Mukherjee🇮🇳 · Sahana Narasimha🇦🇹

   We study the production of axion-like particles (ALPs) in association with electrons and neutrinos in the muon decay process. For this purpose, we compute the decay width of the muon to a four-body channel using a $d=7$ effective operator that couples the ALP to the Standard model fermions, namely leptons and neutrinos. Assuming a dominant coupling of the ALP to the dark sector, we only consider ALP decays to invisible final states. To obtain constraints on our model using the existing measurements, we leverage data from the TRIUMF Weak Interaction Symmetry Test (TWIST) experiment and obtain bounds on the ALP-lepton coupling for masses in the range of $0<m_{\varphi }<m_{\mu }/4$, as allowed by kinematics. Using the precision of current TWIST measurements, we obtain an order of magnitude estimation necessary for future searches to further constrain the parameter space for such a setup. Furthermore, we find that keeping realistic considerations, the new physics contribution can possibly be enhanced even with a minimalistic modification to the fiducial area used in the experiment potentially allowing for stringer constraints. At the end, in an attempt to relax the assumption that ALP decays to invisible only, we also investigate its stability and find potential longevity within collider environments for the mass range considered in this study.

   hep-phhep-exEPJC(2026)·1 citation
3. 03*

   Constraints on freeze-in dark matter from Lyman-$\alpha$ forest and 21-cm signal : single-field models

   Zixuan Xu🇨🇳 · Quan Zhou🇨🇳 · Sibo Zheng🇨🇳

   We report new Lyman-$\alpha$ and 21-cm constraints on freeze-in dark matter (FIDM) which injects energy into the intergalactic medium either through annihilation or decay to photon(s) or electron-positron pair. With respect to Lyman-$\alpha$ we fix the baseline ionization history using low redshift data about astrophysical reionization, whereas for 21-cm signal we adopt the baseline values of 21-cm power spectrum through a standard modeling of star formation developed so far. Using the latest numerical tools, we show that (i) for sterile neutrino FIDM, current Lyman-$\alpha$ data and future sensitivity of SKA-low (1000 hrs) on the 21-cm power spectra excludes the FIDM mass up to $1.8\times 10^{-3}$ GeV at 95$\%$ CL and $5.46\times 10^{-4}$ GeV, respectively, and (ii) for millicharged FIDM, current Lyman-$\alpha$ data only excludes the millicharge down to $10^{-8}$ within the FIDM mass range of $10^{-3}-1$ GeV at 95$\%$ CL, suggesting that the surviving parameter space of millicharged FIDM is still intact.

   hep-phastro-ph.COPRD(2024)·9 citations
4. 04*

   Stable dark matter from Pauli blocking in the degenerate fermion background with Quantum Field Theory

   Wonsub Cho🇰🇷 · Ki-Young Choi🇰🇷 · Junghoon Joh🇰🇷 · Osamu Seto🇯🇵

   We study a mechanism to make dark matter stable based on the Pauli blocking in the fermion background. In the background where fermions occupy the states, the decay of dark matter to those final states is not allowed, as a result, DM becomes stable. We derive the evolution equations of the distribution function in the quantum field theory and compare it with the Boltzmann equation. We apply this mechanism to a realistic model of neutrino and dark matter.

   hep-phastro-ph.COPhys.Dark Univ.(2025)·1 citation
5. 05*

   Higgs pair production at NNLO

   Joshua Davies🇬🇧

   In this talk I report on progress towards the computation of the next-to-next-to-leading order virtual corrections to Higgs boson pair production in gluon fusion, in an expansion around the forward-scattering limit. The results of this computation will provide an estimate of the size and uncertainty of the three-loop virtual corrections in a comparatively much larger region of phase space than the results available in the literature, which are based on an expansion in the limit of a large top quark mass.

   hep-phPoS(2024)·3 citations
6. 06*

   Phenomenology of photons-enriched semi-visible jets

   Cesare Cazzaniga🇨🇭 · Alessandro Russo🇺🇸 · Emre Sitti🇨🇭 · Annapaola de Cosa🇨🇭

   This Letter proposes a new signature for confining dark sectors at the LHC. Under the assumption of a QCD-like hidden sector, hadronic jets containing stable dark bound states originating from hidden strong dynamics, known as semi-visible jets, could manifest in proton-proton collisions. In the proposed simplified model, a heavy $Z^{\prime }$ mediator coupling to SM quarks allows the resonant production of dark quarks, subsequently hadronizing in stable and unstable dark bound states. The unstable dark bound states can then decay back to SM quarks via the same $Z^{\prime }$ portal or photons via a lighter pseudo-scalar portal (such as an axion-like particle). This mechanism creates a new signature where semi-visible jets are enriched in non-isolated photons. We show that these exotic jets evade the phase space probed by current LHC searches exploiting jets or photons due to the expected high jet neutral electromagnetic fraction and photons candidates non-isolation, respectively. In the proposed analysis strategy to tackle such signature, we exploit jets as final state objects to represent the underlying QCD-like hidden sector. We show that, by removing any selection on the neutral electromagnetic fraction from the jet identification criteria, higher signal efficiency can be reached. To enhance the signal-to-background discrimination, we train a deep neural network as a jet tagger that exploits differences in the substructure of signal and background jets. We estimate that with the available triggers for Run 2 and this new strategy, a high mass search can claim a $5\sigma$ discovery (exclusion) of the $Z^{\prime }$ boson with a mass up to 5 TeV (5 TeV) with the full Run 2 data of the LHC when the fraction of unstable dark hadrons decaying to photons pairs is around 30 %, and with a coupling of the $Z^{\prime }$ to SM quarks of 0.25.

   hep-phEPJC(2024)·4 citations
7. 07*

   Search for dark matter mediator in the production of three and four top quarks

   E. Abasov🇷🇺 · E. Boos🇷🇺 · V. Bunichev🇷🇺 · P. Volkov🇷🇺 · G. Vorotnikov🇷🇺 · L. Dudko🇷🇺 · A. Zaborenko🇷🇺 · E. Iudin🇷🇺 · A. Markina🇷🇺 · M. Perfilov🇷🇺 · N. Savkova🇷🇺

   In the context of simplified models of dark matter, the contributions of a scalar mediator to top quark production processes are considered. Tree-level and one-loop contributions of the mediator's decay into a top-antitop quark pair in two-, three-, and four-top quarks production processes are calculated. A significant contribution from diagrams involving the dark matter mediator is demonstrated in the total cross section for three- and four-top quark production processes, taking into account current experimental limits on model parameters. The perspective of searching for dark matter mediators in the processes under consideration is determined by the ability to reconstruct the final state with modern collider detectors and the experimental sensitivity that has already been achieved for such rare events.

   hep-phPhys.Part.Nucl.(2025)·5 citations
8. 08*

   Dynamically assisted pair production enhancement by combined multiple potentials

   Lie-Juan Li🇨🇳 · Li Wang🇨🇳 · Melike Mohamedsedik🇨🇳 · Li-Na Hu🇨🇳 · Bai-Song Xie🇨🇳

   We propose a new Sauter-like field model with combinatorial multiple potentials consisting of a deep slow-varying and some shallow fast-varying potentials. The dynamically assisted Sauter-Schwinger effect on the pair production is found by using the computational quantum field theory. The enhanced pair production is found to be significant at about one order increasing for multiple potentials rather than single potential. In case of dominated by Schwinger mechanism, the obvious time effect leads to electrons concentrating at the two edges of the potential, meanwhile, the momentum locates at the zero nearby. In contrary, however, for the multiphoton processes, the pair generation makes the electrons distributing outside the potential and the momentum appearing multiple peaks far away from zero and evenly evolving toward a step-like structure. An interesting finding is that the particles of pair produced in the alternating potential has a quasi-monoenergetic structure compared to the oscillating potential well or/and potential barrier, which is helpful to achieve the high quality positron source.

   hep-phquant-ph0 citations
9. 09*

   Detection of dilute axion stars with stimulated decay

   Haoran Di🇨🇳 · Haihao Shi🇨🇳 · Zhu Yi🇨🇳

   The anomalous orbits of trans-Neptunian objects can be accounted for by the planet 9 hypothesis. One intriguing possibility is that planet 9 could be a dilute axion star captured by the solar system, with the ratio of the axion star to dark matter being approximately 1/10. Although dilute axion stars can emit monochromatic signals through two-photon decay, the spontaneous decay signal is too weak to be detected by radio telescopes. However, we find that stimulated decay of the dilute axion star, which explains planet 9, can occur by directing a radio beam with a power of 50MW into the star. The resulting echo can be detected by terrestrial telescopes such as SKA, FAST, ngLOBO, and LOFAR. Therefore, the dilute axion star can be distinguished from other planet 9 candidates, such as a primordial black hole or a free-floating planet captured by the solar system.

   hep-phPRD(2025)·5 citations
10. 10*

    Modified dilepton production rate from charged pion-pair annihilation in the inhomogeneous chiral condensed phase

    Kentaro Hayashi🇯🇵 · Yasuhiko Tsue🇯🇵

    We investigate the dilepton production rates from annihilation processes of charged pion pairs with modified pion dispersion relations in the inhomogeneous chiral condensed phase. We assume a dual chiral density wave as an inhomogeneous chiral condensate, and obtain the dispersion relations of the Nambu-Goldstone modes in the inhomogeneous chiral condensed phase. We use a low energy effective Lagrangian based on the O(4) symmetry which is expanded by the order parameter up to the sixth order. The obtained dispersion relations are anisotropic and quadratic for the momentum. We evaluate the electron-positron production rates by charged pion-pair annihilations as functions of an invariant mass using the obtained dispersion relations. Basically, the production rate in the inhomogeneous chiral condensed phase has a steeper overall slope with respect to an invariant mass than that in the homogeneous chiral condensed phase. Therefore, the production rate may be enhanced when the invariant mass is around twice the pion mass.

    hep-phPRD(2024)·4 citations
11. 11*

    Scheme-independent determination of the QCD running coupling at all scales from jet observables using the principle of maximum conformality and infinite-order scale setting

    Leonardo Di Giustino🇮🇹 · Stanley J. Brodsky🇺🇸 · Philip G. Ratcliffe🇮🇹 · Sheng-Quan Wang🇨🇳 · Xing-Gang Wu🇨🇳

    We present a new approach to determining the strong coupling ${\alpha }_s(Q)$, over the entire range of validity of perturbative QCD, for scales above ${\Lambda }_{\mathrm{QCD}}$ and up to the Planck scale $\sim 1.22\cdot 10^{19}$\,GeV, with the highest precision and using the data of a single experiment. In particular, we use the results obtained for the thrust ($T$) and $C$-parameter ($C$) distributions in $e^{+}{e}^{-}$ annihilation at a single annihilation energy $\sqrt{s}=M_Z$ (i.e.\ at the $Z^0$ peak). This new method is based on the \emph{intrinsic conformality} (iCF) and on the Infinite-Order Scale Setting, using the Principle of Maximum Conformality (i.e.\ the PMC${}_{\infty }$), which allows a rigorous determination of the renormalization scales for the event-shape variable distributions satisfying all of the requirements of Renormalization Group Invariance, including renormalization-scheme independence and consistency with Abelian theory in the $N_C\to 0$ limit. This new method is based on the scale-invariance of the iCF, which allows determination of ${\alpha }_s({\mu }_0)$ at any scale ${\mu }_0$, and on the Maximum Likelihood statistical approach. We propose a novel approach to determining the best-fitting range by considering all possible intervals over the entire range of bins available in the perturbative region and selecting that which returns the most-likely-lowest ${\chi }_{\min }^2$. This new method is designed to eliminate the errors that arise due to selection of the bin-interval and that have been neglected in previous analyses. In particular, using data for thrust and $C$-parameter at the $Z^0$ peak from ALEPH, OPAL, DELPHI and L3 experiments, we obtain the average value: ${\alpha }_s(M_Z)=0.1182_{-0.0007}^{+0.0007}$, for the strong coupling. This determination of ${\alpha }_s(M_Z)$ is consistent with the world average...

    hep-phhep-thPLB(2025)·5 citations
12. 12*

    Coherent collision integrals for neutrino transport equations

    Kimmo Kainulainen🇫🇮 · Harri Parkkinen🇫🇮

    We present quantum kinetic equations for neutrinos and derive Feynman rules for computing scattering rates involving coherent states. Our rules encompass both flavour- and particle-antiparticle coherence and allow writing down the scattering matrix elements and collision integrals with the same intuitive ease as with the usual non-coherent Feynman rules. Our results are useful for computing collision rates that arise routinely in the context of coherently mixing neutrinos with arbitrary masses. We give several explicit examples, including some collision integrals for coherently mixing neutrinos in supernovae.

    hep-phastro-ph.HEhep-thJHEP(2024)·4 citations
13. 13*

    Analysis of the ${\Xi }_c^{\ast }\bar{K}$ molecular pentaquark state by its electromagnetic properties

    U. Özdem🇹🇷

    We are systematically studying the electromagnetic characteristics of multiquark systems to shed light on their internal structure, whose nature and quantum numbers are controversial. In this study, we investigate the magnetic dipole, electric quadrupole, and magnetic octupole moments of the ${\Xi }_c^{\ast }\bar{K}$ state within the context of the QCD light-cone sum rule. During this analysis, we posit that the ${\Xi }_c^{\ast }\bar{K}$ state assumes a molecular structure with quantum numbers $J^P={\frac{3}{2}}^{-}$. The extracted outcomes are given as ${\mu }_{{\Xi }_c^{\ast }\bar{K}}=0.15_{-0.03}^{+0.04}{\mu }_N$, ${\mathcal{Q}}_{{\Xi }_c^{\ast }\bar{K}}=(-0.93_{-0.17}^{+0.22})\times 10^{-3}\mathrm{f}{\mathrm{m}}^2$, and ${\mathcal{O}}_{{\Xi }_c^{\ast }\bar{K}}=(-0.45_{-0.09}^{+0.10})\times 10^{-4}\mathrm{f}{\mathrm{m}}^3$. The findings of this study, when considered alongside other pertinent characteristics, may assist in elucidating the nature of this controversial phenomenon.

    hep-phhep-exhep-latEPJC(2024)·7 citations
14. 14*

    Conformal BK equation at QCD Wilson-Fisher point

    Ian Balitsky🇺🇸 · Giovanni A. Chirilli🇮🇹

    High-energy scattering in pQCD in the Regge limit is described by the evolution of Wilson lines governed by the BK equation. In the leading order, the BK equation is conformally invariant and the eigenfunctions of the linearized BFKL equation are powers. It is a common belief that at $d\ne 4$ the BFKL equation is useless since unlike $d=4$ case it cannot be solved by usual methods. However, we demonstrate that at critical Wilson-Fisher point of QCD the relevant part of NLO BK restores the conformal invariance so the solutions are again powers. As a check of our approach to high-energy amplitudes at the Wilson-Fisher point, we calculate the anomalous dimensions of twist-2 light-ray operators in the Regge limit $j\to 1$.}

    hep-phhep-thJHEP(2024)·4 citations
15. 15*

    On the impact of heavy meson production spectra on searches for heavy neutral leptons

    Jonathan L. Schubert (1 and 2)🇩🇪 · Babette Döbrich (2)🇩🇪 · Jan Jerhot (2)🇩🇪 · Tommaso Spadaro (3) ((1) Technical University of Munich, (2) Max-Planck-Institut für Physik, (3) Laboratori Nazionali di Frascati dell INFN)🇮🇹

    Feebly Interacting Particles are a commonly considered extension to the Standard Model of Particle Physics. In many theoretical frameworks these particles can explain observed physical phenomena which are in tension with the current model. \textsc{ALPiNIST} is a simplified Monte Carlo framework aimed at evaluating past, present, and future, short and long baseline experiments for their sensitivities to different models of Axion-Like Particles. We present the extension of this framework to accommodate new classes of Feebly Interacting Particles with emphasis on Heavy Neutral Leptons. This extension is especially well motivated, solving multiple of the standing issues with the Standard Model at the same time. The fundamental importance of inputs on the resulting parameter sensitivity, and thus the need for a unified simulation set-up, is highlighted.

    hep-phJHEP(2025)·8 citations
16. 16*

    Non-universal SUSY models, $g_{\mu }-2$, $m_H$ and dark matter

    John Ellis🇬🇧 · Keith A. Olive🇺🇸 · Vassilis C. Spanos🇬🇷

    We study the anomalous magnetic moment of the muon, $g_{\mu }-2\equiv 2a_{\mu }$, in the context of supersymmetric models beyond the CMSSM, where the unification of either the gaugino masses $M_{1,2,3}$ or sfermion and Higgs masses is relaxed, taking into account the measured mass of the Higgs boson, $m_H$, the cosmological dark matter density and the direct detection rate. We find that the model with non-unified gaugino masses can make a contribution $\Delta a_{\mu }\sim 20\times 10^{-10}$ to the anomalous magnetic moment of the muon, for example if $M_{1,2}\sim 600$ GeV and $M_3\sim 8$ TeV. The model with non-universal sfermion and Higgs masses can provide even larger $\Delta a_{\mu }\sim 24\times 10^{-10}$ if the sfermion masses for the first and the second generations are $\sim 400$ GeV and that of the third is $\sim 8$ TeV. We discuss the prospects for collider searches for supersymmetric particles in specific benchmark scenarios illustrating these possibilities, focusing in particular on the prospects for detecting the lighter smuon and the lightest neutralino.

    hep-phastro-ph.COhep-exhep-thEPJC(2024)·8 citations
17. 17*

    Jet Tagging with More-Interaction Particle Transformer

    Yifan Wu🇨🇳 · Kun Wang🇨🇳 · Congqiao Li🇨🇳 · Huilin Qu🇨🇭 · Jingya Zhu🇨🇳

    In this study, we introduce the More-Interaction Particle Transformer (MIParT), a novel deep learning neural network designed for jet tagging. This framework incorporates our own design, the More-Interaction Attention (MIA) mechanism, which increases the dimensionality of particle interaction embeddings. We tested MIParT using the top tagging and quark-gluon datasets. Our results show that MIParT not only matches the accuracy and AUC of LorentzNet and a series of Lorentz-equivariant methods, but also significantly outperforms the ParT model in background rejection. Specifically, it improves background rejection by approximately 25% at a 30% signal efficiency on the top tagging dataset and by 3% on the quark-gluon dataset. Additionally, MIParT requires only 30% of the parameters and 53% of the computational complexity needed by ParT, proving that high performance can be achieved with reduced model complexity. For very large datasets, we double the dimension of particle embeddings, referring to this variant as MIParT-Large (MIParT-L). We find that MIParT-L can further capitalize on the knowledge from large datasets. From a model pre-trained on the 100M JetClass dataset, the background rejection performance of the fine-tuned MIParT-L improved by 39% on the top tagging dataset and by 6% on the quark-gluon dataset, surpassing that of the fine-tuned ParT. Specifically, the background rejection of fine-tuned MIParT-L improved by an additional 2% compared to the fine-tuned ParT. The results suggest that MIParT has the potential to advance efficiency benchmarks for jet tagging and event identification in particle physics. The code is available at the following GitHub repository: https://github.com/USST-HEP/MIParT

    hep-phhep-exphysics.data-anCPC(2025)·38 citations
18. 18*

    Revisiting $C$ and $CP$ Violation in $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ Decay

    Jun Shi🇨🇳 · Jian Liang🇨🇳 · Susan Gardner🇺🇸

    The decay $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ is an ideal process in which to study flavor-conserving $C$ and $CP$ violation beyond the Standard Model. We deduce the $C$- and $CP$-odd quark operators that contribute to $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ originating from the mass-dimension 6 Standard Model effective field theory. The corresponding hadron-level operators that generate a non-vanishing $I=0$ amplitude at order $p^6$ in the chiral effective theory are presented for the first time, in addition to the leading order operatorsascribed to the $I=2$ final state. By fitting the KLOE-2 and the most recent BESIII experimental data, we determine the coefficients of the lowest order $I=0$ and $I=2$ amplitudes and estimate the potential new physics energy scale. We also perform an impact study of the future $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ experiments.

    hep-phhep-exPRD(2024)·4 citations
19. 19*

    Dark matter limits from the tip of the red giant branch of globular clusters

    Haozhi Hong🇨🇦 · Aaron C. Vincent🇨🇦

    Capture and annihilation of WIMP-like dark matter in red giant stars can lead to faster-than-expected ignition of the helium core, and thus a lower tip of the red giant branch (TRGB) luminosity. We use Gaia data to place constraints on the dark matter-nucleon cross section using 22 globular clusters with measured TRGB luminosities, and place projections on the sensitivity resulting from 161 clusters with full phase space distributions observed by Gaia. Although limits remain weaker than those from Earth-based direct detection experiments, they represent a constraint that is fully independent of dark matter properties in the Solar neighbourhood, probing its properties across the entire Milky Way galaxy. Based on our findings, it is likely that the use of the TRGB as a standard candle in $H_0$ measurements is very robust against the effects of dark matter.

    hep-phastro-ph.COastro-ph.GAastro-ph.HE+1PRD(2024)·5 citations
20. 20*

    A particle's perspective on screening mechanisms

    Sergio Sevillano Muñoz🇬🇧

    Screening mechanisms are a natural method for suppressing long-range forces in scalar-tensor theories as they link the local background density to their strength. Focusing on Brans-Dicke theories, those including a non-minimal coupling between a scalar degree of freedom and the Ricci scalar, we study the origin of these screening mechanisms from a field theory perspective, considering the influence of the Standard Model on the mechanisms. Additionally, we further consider the role of scale symmetries on screening, demonstrating that only certain sectors, those obtaining their mass via the Higgs mechanism, contribute to screening the fifth forces. This has significant implications for baryons, which obtain most of their mass from the gluon's binding energy. Given that the Planck mass is related to the vacuum expectation value of the non-minimally coupled field, we find an extensive region of the parameter space where screening mechanisms create a spatially dependent gravitational constant. We say that the field over-screens when this effect is more significant than the fifth forces suppressed by screening mechanisms, as we illustrate for the chameleon and symmetron models.

    hep-phgr-qchep-thJCAP(2024)·12 citations
21. 21*

    Unsupervised Beyond-Standard-Model Event Discovery at the LHC with a Novel Quantum Autoencoder

    Callum Duffy🇬🇧 · Mohammad Hassanshah🇬🇧 · Marcin Jastrzebski🇬🇧 · Sarah Malik🇬🇧

    This study explores the potential of unsupervised anomaly detection for identifying physics beyond the Standard Model that may appear at proton collisions at the Large Hadron Collider. We introduce a novel quantum autoencoder circuit ansatz that is specifically designed for this task and demonstrates superior performance compared to previous approaches. To assess its robustness, we evaluate the quantum autoencoder on various types of new physics 'signal' events and varying problem sizes. Additionally, we develop classical autoencoders that outperform previously proposed quantum autoencoders but remain outpaced by the new quantum ansatz, despite its significantly reduced number of trainable parameters. Finally, we investigate the properties of quantum autoencoder circuits, focusing on entanglement and magic. We introduce a novel metric in the context of parameterised quantum circuits, stabilizer 2-Rényi entropy to quantify magic, along with the previously studied Meyer-Wallach measure for entanglement. Intriguingly, both metrics decreased throughout the training process along with the decrease in the loss function. This appears to suggest that models preferentially learn parameters that reduce these metrics. This study highlights the potential utility of quantum autoencoders in searching for physics beyond the Standard Model at the Large Hadron Collider and opens exciting avenues for further research into the role of entanglement and magic in quantum machine learning more generally.

    ↳ quant-phhep-exhep-phQuantum Machine Intelligence(2025)·11 citations
22. 22*

    Radiative corrections to proton-proton fusion in pionless EFT

    Evan Combes🇺🇸 · Emanuele Mereghetti🇺🇸 · Lucas Platter🇺🇸

    We study the leading radiative correction to proton-proton fusion using the pionless effective field theory framework at leading order. We derive the relevant matrix elements and evaluate them using the method of regions. We benchmark the accuracy of our approximations by carrying out numerical computations of the full expressions. We show that the first order radiative corrections due to the exchange of a Coulomb photon between positron and proton-proton systems map onto the Sirlin function and the $\mathcal{O}(\alpha )$ contribution from the Fermi function. We furthermore find that the nuclear structure dependent radiative correction omitted in the previous analysis by Kurylov {\it et al} gives an up to 0.2~\% correction to the pp fusion S-factor with its size ultimately depending on a two-nucleon counterterm that renormalizes the axial two-body current $L_{1A}$.

    ↳ nucl-thhep-phPRC(2024)·5 citations
23. 23*

    Investigating tidal heating in neutron stars via gravitational Raman scattering

    M. V. S. Saketh🇺🇸 · Zihan Zhou🇺🇸 · Suprovo Ghosh🇮🇳 · Jan Steinhoff🇩🇪 · Debarati Chatterjee🇮🇳

    We present a scattering amplitude formalism to study the tidal heating effects of nonspinning neutron stars incorporating both worldline effective field theory and relativistic stellar perturbation theory. In neutron stars, tidal heating arises from fluid viscosity due to various scattering processes in the interior. It also serves as a channel for the exchange of energy and angular momentum between the neutron star and its environment. In the interior of the neutron star, we first derive two master perturbation equations that capture fluid perturbations accurate to linear order in frequency. Remarkably, these equations receive no contribution from bulk viscosity due to a peculiar adiabatic incompressibility which arises in stellar fluid for non-barotropic perturbations. In the exterior, the metric perturbations reduce to the Regge-Wheeler (RW) equation which we solve using the analytical Mano-Suzuki-Takasugi (MST) method. We compute the amplitude for gravitational waves scattering off a neutron star, also known as gravitational Raman scattering. From the amplitude, we obtain expressions for the electric quadrupolar static Love number and the leading dissipation number to all orders in compactness. We then compute the leading dissipation number for various realistic equation-of-state(s) and estimate the change in the number of gravitational wave cycles due to tidal heating during inspiral in the LIGO-Virgo-KAGRA (LVK) band.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2024)·45 citations
24. 24*

    Operator Origin of Anomalous Dimensions in de Sitter Space

    Timothy Cohen🇨🇭 · Daniel Green🇺🇸 · Yiwen Huang🇺🇸

    The late time limit of the power spectrum for heavy (principal series) fields in de Sitter space yields a series of polynomial terms with complex scaling dimensions. Such scaling behavior is expected to result from an associated operator with a complex dimension. In a free theory, these complex dimensions are known to match the constraints imposed by unitarity on the space of states. Yet, perturbative corrections to the scaling behavior of operators are naively inconsistent with unitary evolution of the quantum fields in dS. This paper demonstrates how to compute one-loop corrections to the scaling dimensions that appear in the two point function from the field theory description in terms of local operators. We first show how to evaluate these anomalous dimensions using Mellin space, which has the feature that it naturally accommodates a scaleless regulator. We then explore the consequences for the Soft de Sitter Effective Theory (SdSET) description that emerges in the long wavelength limit. Carefully matching between the UV and SdSET descriptions requires the introduction of novel non-dynamical "operators" in the effective theory. This is not only necessary to reproduce results extracted from the Källén-Lehmann representation (that use the space of unitary states directly), but it is also required by general arguments that invoke positivity.

    ↳ hep-thastro-ph.COhep-phPRD(2025)·19 citations
25. 25*

    A unitary coupled-channel three-body amplitude with pions and kaons

    Yuchuan Feng🇺🇸 · Fernando Gil🇪🇸 · Michael Döring🇺🇸 · Raquel Molina🇪🇸 · Maxim Mai🇺🇸 · Vanamali Shastry🇺🇸 · Adam Szczepaniak🇺🇸

    Three-body dynamics above threshold is required for the reliable extraction of many amplitudes and resonances from experiment and lattice QCD. The S-matrix principle of unitarity can be used to construct dynamical coupled-channel approaches in which three particles scatter off each other, re-arranging two-body subsystems by particle exchange. This paper reports the development of a three-body coupled-channel, amplitude including pions and kaons. The unequal-mass amplitude contains two-body S- and P-wave subsystems ("isobars") of all isospins, $I=0,1/2,1,3/2,2$, and it also allows for transitions within a given isobar. The $f_0(500)("\sigma "),f_0(980),\rho (700),K_0^{\ast }(700)("\kappa ")$, and $K^{\ast }(892)$ resonances are included, apart from repulsive isobars. Different methods to evaluate the amplitude for physical momenta are discussed. Production amplitudes for $a_1$ quantum numbers are shown as a proof of principle for the numerical implementation.

    ↳ nucl-thhep-lathep-phnucl-exPRD(2024)·27 citations
26. 26*

    Massive-ish Particles from Small-ish Scales: Non-Perturbative Techniques for Cosmological Collider Physics from Large-Scale Structure Surveys

    Samuel Goldstein🇺🇸 · Oliver H. E. Philcox🇺🇸 · J. Colin Hill🇺🇸 · Lam Hui🇺🇸

    Massive particles produced during inflation impact soft limits of primordial correlators. Searching for these signatures presents an exciting opportunity to uncover the particle spectrum in the inflationary epoch. We present non-perturbative methods to constrain intermediate-mass scalars ($0\le m/H<3/2$, where $H$ is the inflationary Hubble scale) produced during inflation, which give rise to a power-law scaling in the squeezed primordial bispectrum. Exploiting the large-scale structure consistency relations and the separate universe approach, we derive models for the late-time squeezed matter bispectrum and collapsed matter trispectrum sourced by these fields. To validate our models, we run $N$-body simulations with the "Cosmological Collider" squeezed bispectrum for two different particle masses. Our models yield unbiased constraints on the amplitude of non-Gaussianity, $f_{\mathrm{NL}}^{\Delta }$, from the squeezed bispectrum and collapsed trispectrum deep into the non-linear regime ($k_{\max }\approx 2h/\mathrm{Mpc}$ at $z=0$). We assess the information content of these summary statistics, emphasizing the importance of sample variance cancellation in the matter sector. We also study the scale-dependent halo bias in our simulations. For mass-selected halos, the non-Gaussian bias estimated from our simulations agrees with predictions based on (i) separate universe simulations and (ii) universal mass functions. With further work, these results can be used to search for inflationary massive particle production with upcoming galaxy surveys.

    ↳ astro-ph.COhep-phPRD(2024)·23 citations

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