Thu·Apr 20, 2023Thursday·April 20, 2023

1. 01*

   Parton Labeling without Matching: Unveiling Emergent Labelling Capabilities in Regression Models

   Shikai Qiu🇺🇸 · Shuo Han🇺🇸 · Xiangyang Ju🇺🇸 · Benjamin Nachman🇺🇸 · Haichen Wang🇺🇸

   Parton labeling methods are widely used when reconstructing collider events with top quarks or other massive particles. State-of-the-art techniques are based on machine learning and require training data with events that have been matched using simulations with truth information. In nature, there is no unique matching between partons and final state objects due to the properties of the strong force and due to acceptance effects. We propose a new approach to parton labeling that circumvents these challenges by recycling regression models. The final state objects that are most relevant for a regression model to predict the properties of a particular top quark are assigned to said parent particle without having any parton-matched training data. This approach is demonstrated using simulated events with top quarks and outperforms the widely-used ${\chi }^2$ method.

   hep-phhep-exphysics.data-anEPJC(2023)·9 citations
2. 02*

   Coulomb Corrections for Coherent Neutrino Nucleus Scattering

   Ryan Plestid🇺🇸

   In this work we consider sub-leading $O(Z^2{\alpha }^3)$ corrections to coherent elastic neutrino nucleus scattering (CEvNS). These corrections are not negligible by power counting since nuclei with large coherent cross sections have sizeable nuclear charges e.g.\ $Z\alpha \sim 0.4$. We find that the corrections are much smaller than naive power counting in $Z\alpha$ would suggest and that Coulomb corrections do not substantially alter predictions for CEvNS in the Standard Model. We comment on similarities to older literature on mesonic and muonic atoms.

   hep-phhep-exnucl-exnucl-th+1JHEP(2025)·1 citation
3. 03*

   Propagation of gauge fields in hot and dense plasmas at higher orders

   Andreas Ekstedt🇸🇪

   Thermal field theory is indispensable for describing hot and dense systems. Yet perturbative calculations are often stymied by a host of energy scales, and tend to converge slowly. This means that precise results require the apt use of effective field theories. In this paper we refine the effective description of slowly varying gauge field known as hard thermal loops. We match this effective theory to the full theory to two-loops. Our results apply for any renormalizable model and fermion chemical potential. We also discuss how to consistently define asymptotic masses at higher orders; and how to treat spectral functions close to the lightcone. In particular, we demonstrate that the gluon mass is well-defined to next-to-leading order.

   hep-phnucl-th11 citations
4. 04*

   Contribution from Intrinsic Charm Production to Fixed-Target Interactions at the LHC

   R. Vogt🇺🇸

   Background: Intrinsic charm, nonperturbative charm in the hadron wavefunction, has long been speculated but has never been satisfactorily proven. Open charm and $J/\psi$ measurements in a fixed-taget configuration at the LHCb searched for this contribution but reported no evidence. Purpose: $\overline{D}$ meson and $J/\psi$ production is calculated for the SMOG fixed-target configuration in the LHCb experiment using a combination of perturbative QCD and intrinsic charm to see whether intrinsic chaarm would indeed be observable in the SMOG kinematics. Methods: Open charm and $J/\psi$ production is calculated to next-to-leading order in perturbative QCD. Because a gas jet nuclear target is used, cold nuclear matter effects are included in the perturbative calculations. The intrinsic charm is calculated assuming production from a $|uudc\overline{c}⟩$ Fock state. Results: The differential rapidity and transverse momentum distributions in $p+\mathrm{Ne}$, $p+\mathrm{He}$ and $p+\mathrm{Ar}$ fixed-target interactions are calculated in the SMOG acceptance and compared to data. The predicted asymmetries between $\overline{D}$ (leading charm) and $D$ (nonleading charm) are also shown. Conclusions: The contribution from intrinisic charm is small and decreases with center of mass energy. The calculations agree well with the current SMOG data, with or without intrinsic charm.

   hep-phPRC(2023)·9 citations
5. 05*

   The decay $\tau \to 3\pi {\nu }_{\tau }$ and axial-vector meson $a_1$ in the NJL model

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

   The branching fractions of $\tau \to {\pi }^{+}{\pi }^{-}{\pi }^{-}{\nu }_{\tau }$ and $\tau \to {\pi }^{-}2{\pi }^0{\nu }_{\tau }$ are calculated within the chiral NJL model. Features of the axial-vector $a_1$ meson which plays an important role in describing the $\tau$ decays are discussed. Permissible values for the mass and width of the $a_1$ meson are considered in accordance with the latest experiments.

   hep-phMod.Phys.Lett.A(2023)·0 citations
6. 06*

   Transverse momentum dependent shape function for $J/\psi$ production in SIDIS

   Daniël Boer🇳🇱 · Jelle Bor🇳🇱 · Luca Maxia🇳🇱 · Cristian Pisano🇮🇹 · Feng Yuan🇺🇸

   It has been shown previously that the transverse momentum dependent (TMD) factorization of heavy quarkonium production requires a TMD shape function. Its perturbative tail can be extracted by matching the cross sections valid at low and high transverse momenta. In this article we compare the order-${\alpha }_s$ TMD expressions with the order-${\alpha }_s^2$ collinear ones for $J/\psi$ production in semi-inclusive deep inelastic scattering (SIDIS), employing nonrelativistic QCD in both cases. In contrast to previous studies, we find that the small transverse momentum limit of the collinear expressions contain discontinuities. We demonstrate how to properly deal with them and include their finite contributions to the TMD shape functions. Moreover, we show that soft gluon emission from the low transverse momentum Born diagrams provide the same leading order TMD shape functions as required for the matching. Their revised perturbative tails have a less divergent behaviour as compared to the TMD fragmentation functions of light hadrons. Finally, we investigate the universality of TMD shape functions in heavy quarkonium production, identify the need for process dependent factorization and discuss the phenomenological implications.

   hep-phhep-exJHEP(2023)·43 citations
7. 07*

   Resonant and polarization effects in the processes of quantum electrodynamics in a strong magnetic field

   R.I. Kholodov🇺🇦 · O.P. Novak🇺🇦 · M.M. Diachenko🇺🇦

   The monograph considers resonance and polarization effects in quantum electrodynamics processes that take place in a strong external magnetic field. A method for analyzing spin-polarization effects has been developed. The factorization of process cross sections in resonant conditions and the representation of these cross sections in the form of Breit-Wigner are considered. The possibility of testing these effects in modern international projects to test quantum electrodynamics in strong fields is shown.

   hep-ph0 citations
8. 08*

   Khuri-Treiman analysis of $J/\psi \to {\pi }^{+}{\pi }^{-}{\pi }^0$

   JPAC Collaboration: M. Albaladejo🇪🇸 · S. Gonzàlez-Solís🇺🇸 · Ł. Bibrzycki🇵🇱 · C. Fernández-Ramírez🇪🇸 · N. Hammoud🇵🇱 · V. Mathieu🇪🇸 · M. Mikhasenko🇩🇪 · G. Montaña🇺🇸 · R. J. Perry🇪🇸 · A. Pilloni🇮🇹 · A. Rodas🇺🇸 · W. A. Smith🇺🇸 · A. Szczepaniak🇺🇸 · D. Winney🇨🇳

   We study the decay $J/\psi \to {\pi }^{+}{\pi }^{-}{\pi }^0$ within the framework of the Khuri-Treiman equations. We find that the BESIII experimental di-pion mass distribution in the $\rho (770)$-region is well reproduced with a once-subtracted $P$-wave amplitude. Furthermore, we show that $F$-wave contributions to the amplitude improve the description of the data in the $\pi \pi$ mass region around 1.5 GeV. We also present predictions for the $J/\psi \to {\pi }^0{\gamma }^{\ast }$ transition form factor.

   hep-phhep-exnucl-thPRD(2023)·12 citations
9. 09*

   Light-quark Yukawa couplings from off-shell Higgs production

   Elisa Balzani🇮🇹 · Ramona Gröber🇮🇹 · Marco Vitti🇮🇹

   Yukawa couplings of the first quark generation are notoriously difficult to constrain due to their small values within the Standard Model. Here we propose Higgs off-shell production, with the Higgs boson decaying to four leptons, as a probe of the up- and down-quark Yukawa couplings. Using kinematic discriminants similar to the ones employed in the Higgs width measurements we find that the down (up) Yukawa coupling can be constrained to a factor of 156 (260) times its Standard Model value at the high-luminosity LHC assuming only experimental systematic uncertainties. Off-shell Higgs production hence provides better sensitivity to the first-generation quark Yukawa couplings with respect to other probes such as Higgs+jet or Higgs pair production.

   hep-phJHEP(2023)·21 citations
10. 10*

    Transvese momentum dependent parton distributions of pion at leading twist

    Wei Kou🇨🇳 · Chao Shi🇨🇳 · Xurong Chen🇨🇳 · Wenbao Jia🇨🇳

    We calculate the leading twist pion unpolarized transverse momentum distribution $f_1(x,k_T^2)$ and the Boer-Mulders function $h_1^{\perp }(x,k_T^2)$, using leading Fock-state light front wave functions (LF-LFWFs) based on Dyson-Schwinger and Bethe-Salpeter equations. These DS-BSEs based LF-LFWFs provide dynamically generated s- and p-wave components, which are indispensable in producing chirally odd Boer-Mulders function that has one parton spin flipped. Employing a non-perturbative SU(3) gluon rescattering kernel to treat the gauge link of the Boer-Mulders function, we thus obtain both TMDs at hadronic scale and then evolve them to the scale of ${\mu }^2=4.0$ GeV${}^2$. We finally calculate the generalized Boer-Mulders shift and find it to be in agreement with the lattice prediction.

    hep-phnucl-thPRD(2023)·14 citations
11. 11*

    Energy loss of heavy quarks in the presence of magnetic field

    Mohammad Yousuf Jamal🇮🇳 · Jai Prakash🇮🇳 · Indrani Nilima🇮🇳 · Aritra Bandyopadhyay🇩🇪

    We study the heavy quark energy loss in the presence of a background magnetic field. The analysis considers the high magnetic field generated by spectators from initial hard collisions that were incorporated using the medium-modified Debye mass, determined from quark condensates at finite temperature and magnetic field via recent lattice quantum chromodynamics (LQCD) calculations. We analyse the impact of medium polarization on the heavy quark propagation in a quark-gluon plasma formed in relativistic heavy-ion colliders like RHIC and LHC. For simplification, we considered the static medium with constant temperature and magnetic field values. Then, we explore the nuclear modification factor ($R_{AA}$) at different magnitudes of magnetic field strengths at fixed temperatures. The energy loss of heavy quarks significantly increases, leading to $R_{AA}$ suppression at higher magnetic field values

    hep-phnucl-thJ.Phys.G(2024)·17 citations
12. 12*

    Neutrino Constraints and the ATOMKI X17 Anomaly

    Peter B. Denton🇺🇸 · Julia Gehrlein🇨🇭

    Recent data from the ATOMKI group continues to confirm their claim of the existence of a new $\sim 17$ MeV particle. We review and numerically analyze the data and then put into context constraints from other experiments, notably neutrino scattering experiments such as the latest reactor anti-neutrino coherent elastic neutrino nucleus scattering data and unitarity constraints from solar neutrino observations. We show that minimal scenarios are disfavored and discuss the model requirements to evade these constraints.

    hep-phPRD(2023)·36 citations
13. 13*

    UFO 2.0 -- The Universal Feynman Output format

    Luc Darmé🇫🇷 · Céline Degrande🇧🇪 · Claude Duhr🇩🇪 · Benjamin Fuks🇫🇷 · Mark Goodsell🇫🇷 · Gudrun Heinrich🇩🇪 · Valentin Hirschi🇨🇭 · Stefan Höche🇺🇸 · Marius Höfer🇩🇪 · Joshua Isaacson🇺🇸 · Olivier Mattelaer🇧🇪 · Thorsten Ohl🇩🇪 and 7 other authors

    We present an update of the Universal FeynRules Output model format, commonly known as the UFO format, that is used by several automated matrix-element generators and high-energy physics software. We detail different features that have been proposed as extensions of the initial format during the last ten years, and collect them in the current second version of the model format that we coin the Universal Feynman Output format. Following the initial philosophy of the UFO, they consist of flexible and modular additions to address particle decays, custom propagators, form factors, the renormalisation group running of parameters and masses, and higher-order quantum corrections.

    hep-phhep-exEPJC(2023)·149 citations
14. 14*

    Effective Field Theory of the Two Higgs Doublet Model

    Ian Banta🇺🇸 · Timothy Cohen🇺🇸 · Nathaniel Craig🇺🇸 · Xiaochuan Lu🇺🇸 · Dave Sutherland🇬🇧

    We revisit the effective field theory of the two Higgs doublet model at tree level. The introduction of a novel basis in the UV theory allows us to derive matching coefficients in the effective description that resum important contributions from the Higgs vacuum expectation value. The new basis typically provides a significantly better approximation of the full theory prediction than the traditional approach that utilizes the Higgs basis, particularly for alignment away from the decoupling limit.

    hep-phJHEP(2023)·14 citations
15. 15*

    Current Status of the Muon g-2 Interpretations within Two-Higgs-Doublet Models

    Syuhei Iguro🇩🇪 · Teppei Kitahara🇯🇵 · Martin S. Lang🇩🇪 · Michihisa Takeuchi🇨🇳

    In this article, we review and update implications of the muon anomalous magnetic moment (muon $g-2$) anomaly for two-Higgs-doublet models (2HDMs), which are classified according to imposed symmetries and their resulting Yukawa sector. In the minimal setup, the muon $g-2$ anomaly can be accommodated by the type-X (lepto-philic) 2HDM, flavor-aligned 2HDM (FA2HDM), muon-specific 2HDM ($\mu$2HDM), and $\mu \tau$-flavor violating 2HDM. We summarize all relevant experimental constraints from high-energy collider experiments and flavor experiments, as well as the theoretical constraints from the perturbative unitarity and vacuum stability bounds, to these 2HDMs in light of the muon $g-2$ anomaly. We clarify the available parameter spaces of these 2HDMs and investigate how to probe the remaining parameter regions in future experiments. In particular, we find that, due to the updated $B_s\to {\mu }^{+}{\mu }^{-}$ measurement, the remaining parameter region of the FA2HDM is almost equivalent to the one of the type-X 2HDM. Furthermore, based on collider simulations, we find that the type-X 2HDM is excluded and the $\mu$2HDM scenario will be covered with the upcoming Run 3 data.

    hep-phhep-exPRD(2023)·22 citations
16. 16*

    Testing Dirac leptogenesis with the cosmic microwave background and proton decay

    Julian Heeck🇺🇸 · Jan Heisig🇺🇸 · Anil Thapa🇺🇸

    The nature of neutrino masses and the matter-antimatter asymmetry of our universe are two of the most important open problems in particle physics today and are notoriously difficult to test with current technology. Dirac neutrinos offer a solution through a leptogenesis mechanism that hinges on the smallness of neutrino masses and resultant non-thermalization of the right-handed neutrino partners in the early universe. We thoroughly explore possible realizations of this Dirac leptogenesis idea, revealing new windows for highly efficient asymmetry generation. In many of them, the number of relativistic degrees of freedom, $N_{\text{eff}}$, is severely enhanced compared to standard cosmology and offers a novel handle to constrain Dirac leptogenesis with upcoming measurements of the cosmic microwave background. Realizations involving leptoquarks even allow for low-scale post-sphaleron baryogenesis and predict proton decay. These novel aspects render Dirac leptogenesis surprisingly testable.

    hep-phPRD(2023)·16 citations
17. 17*

    Universal dynamics of rogue waves in a quenched spinor Bose condensate

    Ido Siovitz🇩🇪 · Stefan Lannig · Yannick Deller🇩🇪 · Helmut Strobel🇩🇪 · Markus K. Oberthaler🇩🇪 · Thomas Gasenzer🇩🇪

    Isolated many-body systems far from equilibrium may exhibit scaling dynamics with universal exponents indicating the proximity of the time-evolution to a non-thermal fixed point. We find universal dynamics connected with the occurrence of extreme wave excitations in the mutually coupled magnetic components of a spinor gas which propagate in an effectively random potential. The frequency of these rogue waves is affected by the time-varying spatial correlation length of the potential, giving rise to an additional exponent ${\delta }_{\mathrm{c}}\simeq 1/3$ for temporal scaling, which is different from the exponent ${\beta }_V\simeq 1/4$ characterizing the scaling of the correlation length ${\ell }_V\sim t^{{\beta }_V}$ in time. As a result of the caustics, i.e., focusing events, real-time instanton defects appear in the Larmor phase of the spin-1 system as vortices in space and time. The temporal correlations governing the instanton occurrence frequency scale as $t^{{\delta }_{\mathrm{I}}}$. This suggests that the universality class of a non-thermal fixed point could be characterized by different, mutually related exponents defining the evolution in time and space, respectively. Our results have a strong relevance for understanding pattern coarsening from first principles and potential implications for dynamics ranging from the early universe to geophysical dynamics and micro physics.

    ↳ cond-mat.quant-gashep-phPRL(2023)·12 citations
18. 18*

    BCS in the Sky: Signatures of Inflationary Fermion Condensation

    Xi Tong🇨🇳 · Yi Wang🇨🇳 · Chen Zhang🇨🇳 · Yuhang Zhu🇨🇳

    We consider a Bardeen-Cooper-Schrieffer (BCS)-like model in the inflationary background. We show that with an axial chemical potential, the attractive quartic fermion self-interaction can lead to a BCS-like condensation. In the rigid-de Sitter (dS) limit of inflation where backreaction from the inflaton and graviton is neglected, we perform the first computation of the non-perturbative effective potential that includes the full spacetime curvature effects in the presence of the chemical potential, subject to the mean-field approximation whose validity has been checked via the Ginzburg criterion. The corresponding BCS phase transition is always first-order, when the varying Hubble is interpreted as an effective Gibbons-Hawking temperature of dS spacetime. In the condensed phase, the theory can be understood from UV and IR sides as fermionic and bosonic, respectively. This leads to distinctive signatures in the primordial non-Gaussianity of curvature perturbations. Namely, the oscillatory cosmological collider signal is smoothly turned off at a finite momentum ratio, since different momentum ratios effectively probe different energy scales. In addition, such BCS phase transitions can also source stochastic gravitational waves, which are feasible for future experiments.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2024)·45 citations
19. 19*

    Search for the production of dark fermion candidates in association with heavy neutral gauge boson decaying to dimuon in proton-proton collisions at $\sqrt{s}=8$ TeV using the CMS open data

    Y.Mahmoud🇪🇬 · H.Abdallah🇪🇬 · M.T.Hussein🇪🇬 · S.Elgammal🇪🇬

    This analysis shows a search for dark fermion particles produced in association with a heavy neutral gauge boson (Z${}^{\prime }$). The studied events topology are dimuon and a large missing transverse momentum. %We considered the muonic decay of Z${}^{\prime }$. The analyzed data were the Open Data collected by the CMS detector in proton-proton collisions at the LHC in 2012 and correspond to an integrated luminosity of 11.6 fb${}^{-1}$ at $\sqrt{s}=$ 8 TeV. One benchmark scenario the light vector was used for interpreting the data, based on a simplified model so called the mono-Z${}^{\prime }$ model. No evidence of dark fermion candidates was found, 95$\%$ confidence level limits have been set on both Z${}^{\prime }$ and dark fermion masses.

    ↳ hep-exhep-phCPC(2024)·0 citations
20. 20*

    Ionization in a laser assisted ion-ion collision

    O. Novak🇺🇦 · R. Kholodov🇺🇦 · A. N. Artemyev🇩🇪 · A. Surzhykov🇩🇪 · Th. Stoehlker🇩🇪

    The ionization of a hydrogen-like heavy ion by impact of a charged projectile under simultaneous irradiation by a short laser pulse is investigated within the non-perturbative approach, based on numerical solutions of the time-dependent Dirac equation. Special emphasis is placed on the question of whether the laser- and impact-ionization channels interfere with each other, and how this intereference affects the ionization probability. To answer this question we performed detailed calculations for the laser-assisted collisions between hydrogen-like $P{b}^{81+}$ and alpha particles. The results of the calculations clearly indicate that for the experimentally relevant set of (collision and laser) parameters, the interference contribution can reach 10% and can be easily controlled by varying the laser frequency.

    ↳ physics.atom-phhep-phPRA(2023)·0 citations
21. 21*

    Relativistic effects in ionization of heavy hydrogen-like ions by short X-ray pulses

    O. Novak🇺🇦 · M. Diachenko🇺🇦 · R. Kholodov🇺🇦

    The probability of photoionization of a heavy hydrogen like ion is calculated within the relativistic perturbation theory. The Coulomb potential of a heavy nucleus is taken into account accurately by usage of the corresponding solutions of the Dirac equation. The obtained probability is compared with both nonrelativistic limit and with nonperturbative results based on the numerical solution of the time-dependent Dirac equation. Suppression of ionization is observed in the secondary ionization channel at photon frequency of about $\hslash \omega \approx m{c}^2$.

    ↳ physics.atom-phhep-phPhys.Scripta(2023)·0 citations
22. 22*

    K-shell ionization of heavy hydrogen-like ions

    O. Novak🇺🇦 · R. Kholodov🇺🇦 · A. Surzhykov🇩🇪 · A. N. Artemyev🇩🇪 · Th. Stöhlker🇩🇪

    A theoretical study of the K-shell ionization of hydrogen-like ions, colliding with bare nuclei, is performed within the framework of the time-dependent Dirac equation. Special emphasis is placed on the ionization probability that is investigated as a function of impact parameter, collision energy and nuclear charge. To evaluate this probability in a wide range of collisional parameters we propose a simple analytical expression for the transition amplitude. This expression contains three fitting parameters that are determined from the numerical calculations, based on the adiabatic approximation. In contrast to previous studies, our analytical expression for the transition amplitude and ionization probability accounts for the full multipole expansion of the two-center potential and allows accurate description of nonsymmetric collisions of nuclei with different atomic numbers, $Z_1\ne Z_2$. The calculations performed for both symmetric and asymmetric collisions indicate that the ionization probability is reduced when the difference between the atomic numbers of ions increases.

    ↳ physics.atom-phhep-phPRA·9 citations
23. 23*

    Simulating Atomic Dark Matter in Milky Way Analogues

    Sandip Roy🇺🇸 · Xuejian Shen🇺🇸 · Mariangela Lisanti🇺🇸 · David Curtin🇨🇦 · Norman Murray🇨🇦 · Philip F. Hopkins🇺🇸

    Dark sector theories naturally lead to multi-component scenarios for dark matter where a sub-component can dissipate energy through self-interactions, allowing it to efficiently cool inside galaxies. We present the first cosmological hydrodynamical simulations of Milky Way analogues where the majority of dark matter is collisionless Cold Dark Matter (CDM), but a sub-component (6%) is strongly dissipative minimal Atomic Dark Matter (ADM). The simulations, implemented in GIZMO and utilizing FIRE-2 galaxy formation physics to model the standard baryonic sector, demonstrate that the addition of even a small fraction of dissipative dark matter can significantly impact galactic evolution despite being consistent with current cosmological constraints. We show that ADM gas with roughly Standard-Model-like masses and couplings can cool to form a rotating "dark disk" with angular momentum closely aligned with the visible stellar disk. The morphology of the disk depends sensitively on the parameters of the ADM model, which affect the cooling rates in the dark sector. The majority of the ADM gas gravitationally collapses into dark "clumps" (regions of black hole or mirror star formation), which form a prominent bulge and a rotating thick disk in the central galaxy. These clumps form early and quickly sink to the inner ~kpc of the galaxy, affecting the galaxy's star-formation history and present-day baryonic and CDM distributions.

    ↳ astro-ph.GAastro-ph.COhep-phApJL(2023)·58 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.