Wed·Nov 30, 2022Wednesday·November 30, 2022

1. 01*

   PBH-infused seesaw origin of matter and unique gravitational waves

   Debasish Borah🇮🇳 · Suruj Jyoti Das🇮🇳 · Rome Samanta🇨🇿 · Federico R. Urban🇨🇿

   The Standard Model, extended with three right-handed (RH) neutrinos, is the simplest model that can explain light neutrino masses, the baryon asymmetry of the Universe, and dark matter (DM). Models in which RH neutrinos are light are generally easier to test in experiments. In this work, we show that, even if the RH neutrinos are super-heavy ($M_{i=1,2,3}>10^9$ GeV) -- close to the Grand Unification scale -- the model can be tested thanks to its distinct features on the stochastic Gravitational Wave (GW) background. We consider an early Universe filled with ultralight primordial black holes (PBH) that produce a super-heavy RH neutrino DM via Hawking radiation. The other pair of RH neutrinos generates the baryon asymmetry via thermal leptogenesis, much before the PBHs evaporate. GW interferometers can test this novel spectrum of masses thanks to the GWs induced by the PBH density fluctuations. In a more refined version, wherein a $U(1)$ gauge symmetry breaking dynamically generates the seesaw scale, the PBHs also cause observable spectral distortions on the GWs from the $U(1)$-breaking cosmic strings. Thence, a low-frequency GW feature related to DM genesis and detectable with a pulsar-timing array must correspond to a mid- or high-frequency GW signature related to baryogenesis at interferometer scales.

   hep-phastro-ph.COJHEP(2023)·34 citations
2. 02*

   Data-driven extraction of the substructure of quark and gluon jets in proton-proton and heavy-ion collisions

   Yueyang Ying🇺🇸

   The modification of quark- and gluon-initiated jets in the quark-gluon plasma produced in heavy-ion collisions is a long-standing question that has not yet received a definitive answer from experiments. In particular, the size of the modifications in the quark-gluon plasma differs between theoretical models. Therefore a fully data-driven technique is crucial for an unbiased extraction of the quark and gluon jet spectra and substructure. Corroborating past results, I demonstrate the capability of a fully data-driven technique called topic modeling in separating quark and gluon contributions to jet observables. The data-driven topic separation results can further be used to extract jet substructures, such as jet shapes and jet fragmentation function, and their respective QGP modifications. In addition, I propose the use of machine learning constructed observables and demonstrate the potential to increase separability for the input observable. This proof-of-concept study is based on proton-proton and heavy-ion collision events from the PYQUEN generator with statistics accessible in Run 4 of the Large Hadron Collider. These results suggest the potential for an experimental determination of quark- and gluon-jet spectra, their substructures, and their modification in the QGP.

   hep-ph0 citations
3. 03*

   Transverse momentum broadening of medium-induced cascades in expanding media

   Souvik Priyam Adhya🇵🇱 · Krzysztof Kutak🇵🇱 · Wiesław Płaczek🇵🇱 · Martin Rohrmoser🇵🇱 · Konrad Tywoniuk🇳🇴

   In this work, we explore the features of gluonic cascades in static and Bjorken expanding media by numerically solving the full BDIM evolution equations in longitudinal momentum fraction $x$ and transverse momentum $\mathbf{k}$ using the Monte Carlo event generator MINCAS. Confirming the scaling of the energy spectra at low-$x$, discovered in earlier works, we use this insight to compare the amount of broadening in static and expanding media. We compare angular distributions for the in-cone radiation for different medium profiles with the effective scaling laws and conclude that the out-of-cone energy loss proceeds via the radiative break-up of hard fragments, followed by an angular broadening of soft fragments. While the dilution of the medium due to expansion significantly affects the broadening of the leading fragments, we provide evidence that in the low-$x$ regime, which is responsible for most of the gluon multiplicity in the cascade, the angular distributions are very similar when comparing different medium profiles at an equivalent, effective in-medium path length. This is mainly due to the fact that in this regime, the broadening is dominated by multiple splittings. Finally, we discuss the impact of our results on the phenomenological description of the out-of-cone radiation and jet quenching.

   hep-phEPJC(2023)·9 citations
4. 04*

   Theory advances for $t\bar{t}W$ multi-lepton predictions

   Manfred Kraus🇺🇸

   We report on recent theoretical advances in the description of the $pp\to t\bar{t}W$ process. First, we discuss a comparison of many state-of-the-art predictions for multi-lepton signatures including the leading QCD contributions at $\mathcal{O}({\alpha }_s^3{\alpha }^6)$ as well as subleading EW contributions at $\mathcal{O}({\alpha }_s{\alpha }^8)$. Furthermore, we briefly discuss recent improvements using multi-jet merging techniques.

   hep-ph0 citations
5. 05*

   Precision studies for string derived $Z^{\prime }$ dynamics at the LHC

   Andrew McEntaggart🇺🇸 · Alon E. Faraggi🇬🇧 · Marco Guzzi🇺🇸

   We consider $Z^{\prime }$s in heterotic string derived models and study $Z^{\prime }$ resonant production at the TeV scale at the Large Hadron Collider (LHC). We use various kinematic differential distributions for the Drell-Yan process at NNLO in QCD to explore the parameter space of such models and investigate $Z^{\prime }$ couplings. In particular, we study the impact of $Z$-$Z^{\prime }$ kinetic-mixing interactions on forward-backward asymmetry ($A_{FB}$) and other distributions at the LHC.

   hep-phhep-thEPJC(2023)·3 citations
6. 06*

   Radiative corrections to inverse muon decay for accelerator neutrinos

   Oleksandr Tomalak🇺🇸 · Kaushik Borah🇺🇸 · Richard J. Hill🇺🇸 · Kevin S. McFarland🇺🇸 · Daniel Ruterbories🇺🇸

   Inverse muon decay (${\nu }_{\mu }{e}^{-}\to {\nu }_e{\mu }^{-}$) is a promising tool to constrain neutrino fluxes with energies $E_{\nu }\ge 10.9\mathrm{GeV}$. Radiative corrections introduce percent-level distortions to energy spectra of outgoing muons and depend on experimental details. In this paper, we calculate radiative corrections to the scattering processes ${\nu }_{\mu }{e}^{-}\to {\nu }_e{\mu }^{-}$ and ${\bar{\nu }}_e{e}^{-}\to {\bar{\nu }}_{\mu }{\mu }^{-}$. We present the muon energy spectrum for both channels, double-differential distributions in muon energy and muon scattering angle and in photon energy and photon scattering angle, and the photon energy spectrum for the dominant ${\nu }_{\mu }{e}^{-}\to {\nu }_e{\mu }^{-}$ process. Our results clarify and extend the region of applicability of previous results in the literature for the double differential distribution in muon energy and photon energy, and in the muon energy spectrum with a radiated photon above a threshold energy. We provide analytic expressions for single, double and triple differential cross sections, and discuss how radiative corrections modify experimentally interesting observable distributions.

   hep-phhep-exnucl-exnucl-thPRD(2023)·5 citations
7. 07*

   Riding the Seesaw: What Higgsstrahlung May Reveal about Massive Neutrinos

   Tobias Felkl🇦🇺 · Adam Lackner🇦🇺 · Michael A. Schmidt🇦🇺

   We investigate if the projected high-precision measurements of the cross section of the Higgsstrahlung process $e^{+}{e}^{-}\to Zh$ at a future electron-positron collider can be utilised to indirectly probe the fermionic Seesaw models. We consider the two centre-of-mass energies $\sqrt{s}=240$ GeV and $365$ GeV, and compare the collider reaches to constraints from electroweak observables, probes of lepton flavour universality and the existing and prospective bounds from searches for lepton flavour violation. For the analysis we assume the limit of an exactly conserved lepton-number symmetry. We find that while any appreciable correction to the Higgsstrahlung cross section is already strictly constrained in the Type-I Seesaw model, effects of up to $\mathcal{O}(10\%)$ are possible within Type-III Seesaw.

   hep-phEPJC(2023)·1 citation
8. 08*

   Electroweak Axion as the Fuzzy Dark Matter -- A Proposal for the Mixed Fuzzy and Cold Dark Matters

   Yu-Cheng Qiu🇨🇳 · Tsutomu T. Yanagida🇨🇳

   The electroweak axion is identified with the fuzzy dark matter of a mass $m\simeq 10^{-20}$--$10^{-19}\mathrm{eV}$. The model predicts two components of dark matter, one is ultralight and the other is WIMP-like. The Chern-Simons-type interaction between the fuzzy dark matter and photon and the $B+L$ breaking proton decays are predicted.

   hep-phastro-ph.CO3 citations
9. 09*

   Study of parity violation in ${\Lambda }_c^{+}\to \varphi p$ and ${\Lambda }_c^{+}\to \omega p$ decays

   PengCheng Hong🇨🇳 · Fang Yan🇨🇳 · RongGang Ping🇨🇳 · Tao Luo🇨🇳

   Evidence for CP violation in baryonic decays has not been seen in experiments. With large data events accumulated at $e^{+}{e}^{-}$ collider or Large Hadron Collider, the charmed baryon decays would provide a promising laboratory to test the CP symmetry. In this work, we formulate the ${\Lambda }_c^{+}\to \varphi p$ and ${\Lambda }_c^{+}\to \omega p$ decays for the measurements of their asymmetry parameters in weak decays at the BESIII or the LHCb experiments. The polarization transfer is analyzed in the two processes of $e^{+}{e}^{-}\to {\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ and ${\Lambda }_b^0\to {\Lambda }_c^{+}{\pi }^{-}$, and the formulas of the joint angular distribution for these processes are provided. The sensitivity of the measurement of asymmetry parameters for the above two decay processes is estimated for the future experiments.

   hep-phhep-exCPC(2023)·5 citations
10. 10*

    Minimal Zee model for lepton $g-2$ and $W$-mass shifts

    R. Primulando🇮🇩 · J. Julio🇮🇩 · P. Uttayarat🇹🇭

    We present a unique Yukawa structure of the Zee model that can accommodate neutrino oscillation data, solves the muon $g-2$ problem, and explains the recent $W$ boson mass measurement. Our Yukawa structure is minimal in the sense that it contains the least possible number of parameters. In this minimal scenario, neutrino masses are quasidegenerate and are compatible with both normal and inverted orderings. The mixing angle ${\theta }_{23}$ is predicted to lie in the second (first) octant for normal (inverted) ordering. In both cases, the CP violating phase is close to 3$\pi /2$. The minimal texture also predicts a large branching fraction of the heavy neutral Higgs boson into a pair of electron and muon.

    hep-phPRD(2023)·11 citations
11. 11*

    Towards clarifying the possibility of observation of the LHCb hidden-charm pentaquarks $P_c^{+}(4312)$, $P_c^{+}(4337)$, $P_c^{+}(4440)$ and $P_c^{+}(4457)$ in near-threshold charmonium photoproduction off protons and nuclei

    E. Ya. Paryev🇷🇺

    We study the near-threshold $J/\psi$ meson photoproduction from protons and nuclei by considering incoherent direct non-resonant ($\gamma p\to J/\psi p$, $\gamma n\to J/\psi n$) and two-step resonant ($\gamma p\to P_{ci}^{+}\to J/\psi p$, $\gamma n\to P_{ci}^0\to J/\psi n$, $i=1$, 2, 3, 4; $P_{c1}^{+,0}=P_c^{+,0}(4312)$, $P_{c2}^{+,0}=P_c^{+,0}(4337)$, $P_{c3}^{+,0}=P_c^{+,0}(4440)$, $P_{c4}^{+,0}=P_c^{+,0}(4457)$) charmonium production processes. We calculate the absolute excitation functions, energy and momentum distributions for the non-resonant, resonant and for the combined (non-resonant plus resonant) production of $J/\psi$ mesons on protons as well as, using the nuclear spectral function approach, on carbon and tungsten target nuclei at near-threshold incident photon energies by assuming the spin-parity assignments of the hidden-charm resonances $P_c^{+,0}(4312)$, $P_c^{+,0}(4337)$, $P_c^{+,0}(4440)$ and $P_c^{+,0}(4457)$ as $J^P=(1/2{)}^{-}$, $J^P=(1/2{)}^{-}$, $J^P=(1/2{)}^{-}$ and $J^P=(3/2{)}^{-}$ within three different realistic scenarios for the branching ratios of their decays to the $J/\psi p$ and $J/\psi n$ modes (0.25, 0.5 and 1%). We show that will be very hard to measure the $P_{ci}^{+}$ pentaquark states through the scan of the $J/\psi$ total photoproduction cross section on a proton target in the near-threshold energy region around the resonant photon energies of 9.44, 9.554, 10.04 and 10.12 GeV if these branching ratios $\sim$ 1% and less. We also demonstrate that at these photon beam energies the $J/\psi$ energy and momentum combined distributions considered reveal distinct sensitivity to the above scenarios, respectively, at "low" $J/\psi$ total energies and momenta, which implies that they may be an important tool to provide further evidence for the existence of the pentaquark $P_{ci}^{+}$ and $P_{ci}^0$ resonances.

    hep-phhep-exnucl-exNPA(2023)·6 citations
12. 12*

    TopicFlow: Disentangling quark and gluon jets with normalizing flows

    Matthew J. Dolan🇦🇺 · Ayodele Ore🇦🇺

    The isolation of pure samples of quark and gluon jets is of key interest at hadron colliders. Recent work has employed topic modeling to disentangle the underlying distributions in mixed samples obtained from experiments. However, current implementations do not scale to high-dimensional observables as they rely on binning the data. In this work we introduce TopicFlow, a method based on normalizing flows to learn quark and gluon jet topic distributions from mixed datasets. These networks are as performant as the histogram-based approach, but since they are unbinned, they are efficient even in high dimension. The models can also be oversampled to alleviate the statistical limitations of histograms. As an example use case, we demonstrate how our models can improve the calibration accuracy of a classifier. Finally, we discuss how the flow likelihoods can be used to perform outlier-robust quark/gluon classification.

    hep-phPRD(2023)·4 citations
13. 13*

    Dirac Kondo effect under magnetic catalysis

    Koichi Hattori🇨🇳 · Daiki Suenaga🇯🇵 · Kei Suzuki🇯🇵 · Shigehiro Yasui🇯🇵

    We develop a mean-field theory of a novel Kondo effect emerging in systems without a Fermi surface, which instead emerges under strong magnetic fields. We determine the magnitude of the Kondo condensate which is a particle pairing composed of conducting Dirac fermions and localized impurities. We focus on the competition between the Kondo effect and the energy gap formation that stems from the pairing among the Dirac fermions leading to the dynamical chiral symmetry breaking. We find that this competition induces a quantum critical point. We also investigate finite-temperature effects. This system at vanishing fermion density can be studied with Monte Carlo lattice simulations which do not suffer from the sign problem.

    hep-phcond-mat.mes-hallcond-mat.str-elhep-lat+1PRB(2023)·4 citations
14. 14*

    Dineutron decay into sterile anti-neutrinos in neutron stars and its observable consequences

    Yongliang Hao🇨🇳 · Dongdong Ni🇨🇳

    In some extensions of the Standard Model (SM), two neutrons are allowed to decay into two sterile anti-neutrinos ($nn\to \bar{\chi }\bar{\chi }$) via new scalar bosons. This process violates both the baryon number ($\mathcal{B}$) and the lepton number ($\mathcal{L}$) by two units but conserves their difference $(\mathcal{B}-\mathcal{L})$. Neutron stars contain a large number of neutrons and thus the $nn\to \bar{\chi }\bar{\chi }$ process can be greatly enhanced inside a neutron star. This process could result in non-trivial effects that are different from the SM predictions and can be explored through astrophysical and laboratory observations. Furthermore, a large number of sterile antineutrinos, which may be dark matter candidates, can be emitted from the interior of the neutron star. The properties of the emitted particles show a particular pattern that can be uniquely determined by the mass and radius of the neutron star. In addition, the dineutron decay may contribute to the orbital-period change of the binary systems containing neutron stars. We analyze the possibility to constrain the mass of the new scalar bosons using the observations of the binary's orbital-period changes. It is found that the mass of the new scalar bosons is roughly restricted in the range from 1 TeV to several TeV, which is possibly within the reach of direct searches at the LHC or future high-energy experiments. The joint analysis which combines the astrophysics and particle phenomenology could provide an excellent opportunity for the study of the new physical effects beyond the SM.

    hep-phPRD(2023)·2 citations
15. 15*

    $D_1(2420)$ and its interactions with a kaon: open charm states with strangeness

    Brenda B. Malabarba🇧🇷 · K. P. Khemchandani🇧🇷 · A. Martinez Torres🇧🇷 · E. Oset🇪🇸

    In this work we present an attempt to describe the $X_1(2900)$ found by the LHCb collaboration, in the experimental data on the invariant mass spectrum of $D^{-}{K}^{+}$, as a three-meson molecular state of the $K\rho \bar{D}$ system. We discuss that the interactions in all the subsystems are attractive in nature, with the $\rho \bar{D}$ interaction generating ${\bar{D}}_1(2420)$ and the $K\rho$ resonating as $K_1(1270)$. We find that the system can form a three-body state but with a mass higher than that of $X_1(2900)$. We investigate the $K\rho D$ system too, finding that the three-body dynamics generates an isoscalar state, which can be related to $D_{s1}^{\ast }(2860)$, and an exotic isovector state. This latter state has a mass similar to that of the $X_0(2900)$ and $X_1(2900)$ states found by LHCb, but a very small width ($\sim 7.4\pm 0.9$ MeV) and necessarily requires more than two quarks to describe its properties. We hope that our findings will encourage experimental investigations of the isovector $K\rho D$ state. Finally, in the pursuit of finding a description for $X_1(2900)$, we study the $\pi {\bar{K}}^{\ast }{D}^{\ast }$ system where ${\bar{K}}^{\ast }{D}^{\ast }$ forms $0^{+}$, $1^{+}$ and $2^{+}$ states. We do not find a state which can be associated with $X_1(2900)$.

    hep-phnucl-thPRD(2023)·7 citations
16. 16*

    Probing first-order electroweak phase transition via primordial black holes in the effective field theory

    Katsuya Hashino🇯🇵 · Shinya Kanemura🇯🇵 · Tomo Takahashi🇯🇵 · Masanori Tanaka🇯🇵

    We investigate production of primordial black holes from first-order electroweak phase transition in the framework of the nearly aligned Higgs effective field theory, in which non-decoupling quantum effects are properly described. Since the mass of such primordial black holes is evaluated to be about $10^{-5}$ of the solar mass, current and future microlensing observations such as Subaru HSC, OGLE, PRIME and Roman Space Telescope may be able to probe the electroweak phase transition. We study parameter regions where primordial black holes can be produced by the first-order electroweak phase transition, and explore their detectability at these observations. Complementarity of primordial black hole observations, gravitational wave observations and collider experiments is also discussed for testing the nature of the electroweak phase transition.

    hep-phastro-ph.COPLB(2023)·43 citations
17. 17*

    Quark-Hadron Transition and Entanglement

    Berndt Müller🇺🇸 · Andreas Schäfer🇩🇪

    The dual holographic description has enjoyed many successes in explaining fundamental properties of the early stages of relativistic heavy ion collisions up to the formation of a minimal-viscosity quark-gluon fluid. However, there have been few attempts to extend its application beyond this stage. Here we explore the prospects for such an extension beyond the time of hadronization. Our discussion makes use of recent insights into the duality of entanglement properties of field theory states in the edge of Anti-de Sitter space and non-trivial topologies of horizons in the bulk, often referred to as ER = EPR duality. We discuss this topic from the point of view of heavy-ion phenomenology, review several relevant concepts, and map out a path toward combining them into a comprehensive, at least semiquantitative description of relativistic heavy ion collisions. We outline possible next steps in this direction.

    hep-phnucl-th11 citations
18. 18*

    Nuclear effects in coherent photoproduction of heavy quarkonia

    J. Nemchik🇨🇿 · B.Z. Kopeliovich🇨🇱

    Coherent photoproduction of heavy quarkonia on nuclear targets is studied within the QCD color dipole formalism including several main phenomena: i) The correlation between impact parameter of a collision $\vec{b}$ and dipole orientation $\vec{r}$; ii) The higher-twist nuclear shadowing related to the $\bar{Q}Q$ Fock state of the photon; iii) The leading-twist gluon shadowing corresponding to higher Fock components of the photon containing gluons; iv) Reduced effects of quantum coherence in a popular Balitsky-Kovchegov equation compared to calculations, which are frequently presented in the literature. Our calculations of differential cross sections are in good agreement with recent ALICE data on charmonium production in ultra-peripheral nuclear collisions. We present also predictions for coherent photoproduction of other quarkonium states (${\psi }^{\prime }$(2S), ${\rm Y}$(1S) and ${{\rm Y}}^{\prime }$(2S)) that can be verified by future measurements at the LHC.

    hep-phActa Phys.Polon.Supp.(2023)·1 citation
19. 19*

    GRIFFIN: A C++ library for electroweak radiative corrections in fermion scattering and decay processes

    Lisong Chen🇺🇸 · Ayres Freitas🇺🇸

    This paper describes a modular framework for the description of electroweak scattering and decay processes, including but not limited to Z-resonance physics. The framework consistently combines a complex-pole expansion near a s-channel resonance with a regular fixed-order perturbative description away from the resonance, in a manifestly gauge-invariant scheme. Leading vertex correction contributions are encapsulated in form factors that can be predicted or treated as numerical fit parameters. This framework has been implemented in the publicly available object-oriented C++ library GRIFFIN. Version 1.0 of this library provides Standard Model predictions for the process $f\bar{f}\to f^{\prime }{\bar{f}}^{\prime }$ with full NNLO and leading higher-order contributions on the Z-resonance, and with NLO corrections off resonance. The library can straightforwardly be extended to include higher-order corrections, should they become available, or predictions for new physics models. It can be interfaced with Monte-Carlo programs to account for QED and QCD initial-state and final-state radiation.

    hep-phhep-exSciPost Phys.Codeb.(2023)·22 citations
20. 20*

    Effects of excited electron and contact $ee\gamma \gamma$ interaction in $e^{+}{e}^{-}\to \gamma \gamma$ reaction

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

    The differential cross section and some polarization observables have been calculated for the $e^{+}{e}^{-}\to \gamma \gamma$ reaction taking into account the contribution of the heavy excited electron and the general form $ee\gamma \gamma$ contact interaction. The spin correlation coefficients are calculated for the case when both beams have arbitrary polarization. The so called left-right asymmetry is estimated if only one beam is polarized. Numerical estimations are given for the excited electron contribution to the differential cross section and spin correlation coefficients for various values of the electron beam energy and excited electron mass.

    hep-ph1 citation
21. 21*

    An algorithmic approach to finding canonical differential equations for elliptic Feynman integrals

    Christoph Dlapa🇩🇪 · Johannes M. Henn🇩🇪 · Fabian J. Wagner🇩🇪

    In recent years, differential equations have become the method of choice to compute multi-loop Feynman integrals. Whenever they can be cast into canonical form, their solution in terms of special functions is straightforward. Recently, progress has been made in understanding the precise canonical form for Feynman integrals involving elliptic polylogarithms. In this article, we make use of an algorithmic approach that proves powerful to find canonical forms for these cases. To illustrate the method, we reproduce several known canonical forms from the literature and present examples where a canonical form is deduced for the first time. Together with this article, we also release an update for INITIAL, a publicly available Mathematica implementation of the algorithm.

    hep-phhep-thmath-phmath.MPJHEP(2023)·70 citations
22. 22*

    Screening of quark charge and mixing effects on transition moments and M1 decay widths of baryons

    Binesh Mohan🇮🇳 · Thejus Mary S.🇮🇳 · Avijit Hazra🇮🇳 · Rohit Dhir🇮🇳

    Motivated by the precision measurements of heavy flavor baryon masses, we analyze the modification of quark charge by employing the screening effect inside the baryon. In addition, we calculate the isospin mass splitting up to charmed baryons employing isospin symmetry breaking. Consequently, we obtain the masses, magnetic moments, and transition moments of $J^P={\frac{1}{2}}^{+}$ and ${\frac{3}{2}}^{+}$ baryons to predict radiative decay widths for ${\frac{1}{2}}^{\prime +}\to {\frac{1}{2}}^{+}$ and ${\frac{3}{2}}^{+}\to {\frac{1}{2}}^{(\prime )+}$ transitions. Finally, we include the effects of state mixing in flavor degenerate baryon magnetic and transition moments, as well as M1 transition decay widths.

    hep-phPRD(2022)·17 citations
23. 23*

    Four-loop large-n_f contributions to the non-singlet structure functions F_2 and F_L

    A. Basdew-Sharma🇳🇱 · A. Pelloni (Nikhef, Amsterdam)🇳🇱 · Franz Herzog (U. Edinburgh, Higgs Ctr. Theor. Phys.)🇬🇧 · A. Vogt (Liverpool U., Dept. Math.)🇬🇧

    We have calculated the n_f^2 and n_f^3 contributions to the flavour non-singlet structure functions F_2 and F_L in inclusive deep-inelastic scattering at the fourth order in the strong coupling alpha_s. The coefficient functions have been obtained by computing a very large number of Mellin-N moments using the method of differential equations, and then determining the analytic forms in N and Bjorken-x from these. Our new n_f^2 terms are numerically much larger than the n_f^3 leading large-nf parts which were already known; they agree with predictions of the threshold and high-energy resummations. Furthermore our calculation confirms the earlier determination of the four-loop n_f^2 part of the corresponding anomalous dimension. Via the no-pi^2 conjecture/theorem for Euclidean physical quantities, we predict the z4 n_f^3 part of the fifth-order anomalous dimension for the evolution of non-singlet quark distributions.

    hep-phJHEP(2023)·16 citations
24. 24*

    Parton distribution of intrinsic charm in two dimensional QCD

    Siwei Hu🇨🇳 · Yu Jia🇨🇳 · Zhewen Mo🇨🇳 · Xiaonu Xiong🇨🇳 · Mingliang Zhu🇨🇳

    We present a detailed investigation on the intrinsic charm content in a light meson within the 't Hooft model, namely, the two-dimensional QCD in large $N_c$ limit. The intrinsic charm parton distribution function (PDF) of a light meson, which first arises at order $N_c^{-1}$, is explicitly expressed in terms of the 't Hooft wave functions of the light meson and an infinite towers of excited charmed mesons. We also derive the functional forms from the two-dimensional counterparts of the meson cloud model (MCM) and Brodsky-Hoyer-Peterson-Sakai (BHPS) model. We then make a quantitative comparison between our rigorous results and model predictions. We also study how the profile of the intrinsic charm PDF varies with charm quark mass. The average momentum fraction carried by the charm quark inside a light meson is found to decrease faster than $m_c^{-4}$ with increasing charm quark mass.

    hep-phPRD(2023)·3 citations
25. 25*

    Freezing-In Gravitational Waves

    Jacopo Ghiglieri🇫🇷 · Jan Schütte-Engel🇺🇸 · Enrico Speranza🇺🇸

    The thermal plasma in the early universe produced a stochastic gravitational wave (GW) background, which peaks today in the microwave regime and was dubbed the cosmic gravitational microwave background (CGMB). In previous works only single graviton production processes that contribute to the CGMB have been considered. Here we also investigate graviton pair production processes and show that these can lead to a significant contribution if the ratio between the maximum temperature and the Planck mass, $T_{\max }/m_{\mathrm{p}}$, divided by the internal coupling in the heat bath is large enough. As the dark matter freeze-in production mechanism is conceptually very similar to the GW production mechanism from the primordial thermal plasma, we refer to the latter as ``GW freeze-in production''. We show that quantum gravity effects appear in single graviton production and are smaller by a factor $(T_{\max }/m_{\mathrm{p}}{)}^2$ than the leading order contribution. In our work we explicitly compute the CGMB spectrum within a scalar model with quartic interaction.

    hep-phastro-ph.COgr-qchep-th+1PRD(2024)·58 citations
26. 26*

    The New Formulation of Higgs Effective Field Theory

    Zi-Yu Dong🇨🇳 · Teng Ma🇮🇱 · Jing Shu🇨🇳 · Zi-Zheng Zhou🇨🇳

    We present the explicit construction of the effective field theory (EFT) of standard model mass eigenstates. The EFT, which is invariant under $U(1{)}_{\text{e.m.}}\times SU(3{)}_c$, is constructed based on the on-shell method and Young Tableau technique. This EFT serves as a new formulation of the Higgs EFT (HEFT), which can describe the infrared effects of new physics at the electroweak symmetry-breaking phase with greater conciseness. The current HEFT operator basis has a clear physical interpretation, making it more accessible for research in phenomenology. A complete list of HEFT operator bases for any-point vertices up to any dimension could be provided, and three- and four-point bases are provided as examples. Additionally, this framework realized as a Mathematica program can be used to construct the EFT of any type of dark matter or particles with any spin.

    hep-phhep-thJHEP(2023)·19 citations
27. 27*

    Constraints on pseudo-Dirac neutrinos using high-energy neutrinos from NGC 1068

    Thomas Rink🇩🇪 · Manibrata Sen🇩🇪

    Neutrinos can be pseudo-Dirac in Nature - they can be Majorana fermions while behaving effectively as Dirac fermions. Such scenarios predict active-sterile neutrino oscillations driven by a tiny mass-squared difference $(\delta m^2)$, which is an outcome of soft lepton number violation. Oscillations due to tiny $\delta m^2$ can only take place over astrophysical baselines and hence are not accessible in terrestrial neutrino oscillation experiments. This implies that high-energy neutrinos coming from large distances can be naturally used to test this scenario. We use the recent observation of high-energy neutrinos from the active galactic nuclei NGC 1068 by the IceCube collaboration to rule out $\delta m^2$ in the region $[1.4\times 10^{-18},10^{-17}]{\mathrm{eV}}^2$ at more than $90\%$ confidence level - one of the strongest limits to date on the values of $\delta m^2$. We also discuss possible uncertainties which can reduce the sensitivity of these results.

    hep-phastro-ph.HEPLB(2024)·21 citations
28. 28*

    New parameterization and analysis for E6 inspired 331 model

    Rena Ciftci · Abbas Kenan Ciftci · Oleg Popov🇨🇳

    We present a new parameterization for $E_6$ inspired $SU(3{)}_C\times SU(3{)}_L\times U(1{)}_X$ extension of the Standard Model. New setup predicts all Cabibbo-Kobayashi-Maskawa mixing angles and quark masses, total of nine observable variables, within 1-3 standard deviations of the experimental values with a minimum number of input parameters. A detailed numerical analysis and correlations between input parameters and predicted quantities are presented. The best global fit benchmark point corresponds to ${\chi }^2\approx 0.7$ with $\forall \sigma <0.6$. Advantages of the new parameterization and future prospects are discussed as well.

    hep-phLHEP(2024)·3 citations
29. 29*

    Resonance enhancement of the electromagnetic interaction between two charged particles in the bound state in the continuum

    A. I. Agafonov🇷🇺

    In bound states in the continuum (BIC) the mass of a composite particle is greater than the total mass of its constituents. Using the ladder Bethe-Salpeter equation, the BIC state in a system of two charged particles $a$ and $b$ with different masses ($m_b>>m_a$) is investigated. We demonstrate that for the positive binding energy, there are two momentum space regions in which the electromagnetic interaction between the particles is strongly enhanced, and the effective coupling constant turns out to be equal to $\alpha \sqrt{m_b/m_a}$, where $\alpha$ is the fine structure constant. The interaction resonance leads to confinement of the constituents in the BIC state with the positive binding energy which is of the order of the mass of the lighter particle from the pair.

    hep-phhep-thMod.Phys.Lett.A(2023)·1 citation
30. 30*

    $t\bar{t}Z$ in the $4\ell$ channel at NLO in QCD

    Jasmina Nasufi🇩🇪

    NLO QCD corrections to the process $pp\to e^{+}{\nu }_e{\mu }^{-}{\bar{\nu }}_{\mu }{\tau }^{+}{\tau }^{-}b\bar{b}+X$ are presented with the full off-shell effects included. The calculation includes all resonant and non-resonant Feynman diagrams, photon and $Z$-gauge boson contributions, as well as interference effects, all incorporated at the matrix element level. Furthermore all heavy intermediate particles are described via Breit-Wigner propagators. Theoretical uncertainties related to the scale variation and choice of PDF sets were investigated at the integrated and differential level. The modelling is studied by a direct comparison of the full off-shell process to the NWA, where tops, $Z$- and $W$-gauge bosons are on-shell. Moreover, motivated by experimental cuts, we also investigate the impact of imposing a window cut around the mass of the $Z$-gauge boson on the full off-shell predictions.

    hep-ph0 citations
31. 31*

    QED as a many-body theory of worldlines: II. All-order S-matrix formalism

    Xabier Feal🇪🇸 · Andrey Tarasov🇺🇸 · Raju Venugopalan🇺🇸

    In arXiv:2206.04188, we developed a first-quantized worldline formalism for all-order computations of amplitudes in QED. In particular, we demonstrated in this framework an all-order proof of the infrared safety of the Faddeev-Kulish (FK) S-matrix for virtual exchanges in the scattering of charged fermions. In this work, we extend the worldline formalism for both the Dyson and FK S-matrix to consider further the emission and absorption of arbitrary numbers of photons. We show how Low's theorem follows in this framework and derive Weinberg's theorem for the exponentiation of IR divergences. In particular, we extend our all-order proof of the IR safety of the FK S-matrix to both virtual exchanges and real photon emissions. We argue that the worldline approach leads to a modern Wilsonian interpretation of the IR safety of the FK S-matrix and provides a novel template for the treatment of IR divergences in real-time problems. Using Grassmannian integration methods, we derive a simple and powerful result for N-th rank vacuum polarization tensors. Applications of these methods will be discussed in follow-up work.

    ↳ hep-thhep-phnucl-thPRD(2023)·10 citations
32. 32*

    Precision Studies of QCD in the Low Energy Domain of the EIC

    V. Burkert · L. Elouadrhiri · A. Afanasev · J. Arrington · M. Contalbrigo · W. Cosyn · A. Deshpande · D. Glazier · X. Ji · S. Liuti · Y. Oh · D. Richards · T. Satogata · A. Vossen

    The manuscript focuses on the high impact science of the EIC with objective to identify a portion of the science program for QCD precision studies that requires or greatly benefits from high luminosity and low center-of-mass energies. The science topics include (1) Generalized Parton Distributions, 3D imagining and mechanical properties of the nucleon (2) mass and spin of the nucleon (3) Momentum dependence of the nucleon in semi-inclusive deep inelastic scattering (4) Exotic meson spectroscopy (5) Science highlights of nuclei (6) Precision studies of Lattice QCD in the EIC era (7) Science of far-forward particle detection (8) Radiative effects and corrections (9) Artificial Intelligence (10) EIC interaction regions for high impact science program with discovery potential. This paper documents the scientific basis for supporting such a program and helps to define the path toward the realization of the second EIC interaction region.

    ↳ nucl-exhep-exhep-lathep-ph+1PPNP(2023)·95 citations
33. 33*

    Log-enhanced discretization errors in integrated correlation functions

    Leonardo Chimirri🇩🇪 · Nikolai Husung🇬🇧 · Rainer Sommer🇩🇪

    Integrated time-slice correlation functions $G(t)$ with weights $K(t)$ appear, e.g., in the moments method to determine ${\alpha }_s$ from heavy quark correlators, in the muon g-2 determination or in the determination of smoothed spectral functions. For the (leading-order-)normalised moment $R_4$ of the pseudo-scalar correlator we have non-perturbative results down to $a=10^{-2}$ fm and for masses, $m$, of the order of the charm mass in the quenched approximation. A significant bending of $R_4$ as a function of $a^2$ is observed at small lattice spacings. Starting from the Symanzik expansion of the integrand we derive the asymptotic convergence of the integral at small lattice spacing in the free theory and prove that the short distance part of the integral leads to $\log (a)$-enhanced discretisation errors when $G(t)K(t)\sim t$ for small $t$. In the interacting theory an unknown, function $K(a\Lambda )$ appears. For the $R_4$-case, we modify the observable to improve the short distance behavior and demonstrate that it results in a very smooth continuum limit. The strong coupling and the $\Lambda$-parameter can then be extracted. In general, and in particular for $g-2$, the short distance part of the integral should be determined by perturbation theory. The (dominating) rest can then be obtained by the controlled continuum limit of the lattice computation.

    ↳ hep-lathep-phPoS(2023)·15 citations
34. 34*

    Inclusion of heavy spin effects in the $ud\bar{b}\bar{b}$ $I(J^P)=0(1^{-})$ four-quark channel in the Born-Oppenheimer approximation

    Jakob Hoffmann🇩🇪 · André Zimermmane-Santos🇩🇪 · Marc Wagner🇩🇪

    We refine our previous study of a $ud\bar{b}\bar{b}$ tetraquark resonance with quantum numbers $I(J^P)=0(1^{-})$, which is based on antiheavy-antiheavy lattice QCD potentials, by including heavy quark spin effects via the mass difference of the $B$ and the $B^{\ast }$ meson. This leads to a coupled channel Schrödinger equation, where the two channels correspond to $BB$ and $B^{\ast }{B}^{\ast }$, respectively. We search for $\text{mbox}T$ matrix poles in the complex energy plane, but do not find any indication for the existence of a tetraquark resonance in this refined coupled channel approach. We also vary the antiheavy-antiheavy potentials as well as the $b$ quark mass to further understand the dynamics of this four-quark system.

    ↳ hep-lathep-phPoS(2023)·10 citations
35. 35*

    pyhf: pure-Python implementation of HistFactory with tensors and automatic differentiation

    Matthew Feickert🇺🇸 · Lukas Heinrich🇩🇪 · Giordon Stark🇺🇸

    The HistFactory p.d.f. template is per-se independent of its implementation in ROOT and it is useful to be able to run statistical analysis outside of the ROOT, RooFit, RooStats framework. pyhf is a pure-Python implementation of that statistical model for multi-bin histogram-based analysis and its interval estimation is based on the asymptotic formulas of "Asymptotic formulae for likelihood-based tests of new physics". pyhf supports modern computational graph libraries such as TensorFlow, PyTorch, and JAX in order to make use of features such as auto-differentiation and GPU acceleration. In addition, pyhf's JSON serialization specification for HistFactory models has been used to publish 23 full probability models from published ATLAS collaboration analyses to HEPData.

    ↳ hep-exhep-phPoS·26 citations
36. 36*

    Hidden dependencies in model independent tests of DAMA

    Madeleine J. Zurowski🇦🇺

    For nearly two decades the DAMA Collaboration has been observing a modulating signal compatible with that expected from a dark matter presence in our galaxy. However, interpretations of this with the standard assumptions for dark matter particles are strongly ruled out by a large number of other experiments. This tension can be relaxed somewhat by making more tailored choices for the dark matter model and properties of interest, but expanding the models of interest in such a way makes it impossible to test the DAMA modulation conclusively. In order to understand the exact nature of this signal, we need to use a detector based on the same target (NaI(Tl)), which would be sensitive to exactly the same particle interaction models as DAMA. There are a number of such experiments in the data taking or commissioning stages designed to do just this, two of which (ANAIS and COSINE) recently released their results after 3 years of data taking. Interestingly, the modulation observed by the two experiments deviate from each other by 2$\sigma$, while being within 3$\sigma$ of the DAMA result. This paper addresses potential differences between NaI(Tl) based detectors that could lead to the differing results to date, with a particular focus on the quenching factor.

    ↳ hep-exhep-phSciPost Phys.Proc.(2023)·2 citations
37. 37*

    Spin-2 dark matter from anisotropic Universe in bigravity

    Yusuke Manita🇯🇵 · Katsuki Aoki🇯🇵 · Tomohiro Fujita🇯🇵 · Shinji Mukohyama🇯🇵

    Bigravity is one of the natural extensions of general relativity and contains an additional massive spin-2 field which can be a good candidate for dark matter. To discuss the production of spin-2 dark matter, we study fixed point solutions of the background equations for axisymmetric Bianchi type-I Universes in two bigravity theories without Boulware-Deser ghost, i.e., Hassan-Rosen bigravity and Minimal Theory of Bigravity. We investigate the local and global stability of the fixed points and classify them. Based on the general analysis, we propose a new scenario where spin-2 dark matter is produced by the transition from an anisotropic fixed point solution to isotropic one. The produced spin-2 dark matter can account for all or a part of dark matter and can be directly detected by laser interferometers in the same way as gravitational waves.

    ↳ gr-qcastro-ph.COhep-phPRD(2023)·32 citations
38. 38*

    Probing singularities of Landau-gauge propagators with Padé approximants

    Cristiane Y. London🇧🇷 · Diogo Boito🇧🇷 · Attilio Cucchieri🇧🇷 · Tereza Mendes🇧🇷

    Padé approximants are employed in order to study the analytic structure of the four-dimensional SU(2) Landau-gauge gluon and ghost propagators in the infrared regime. The approximants, which are model independent, are used as fitting functions to lattice data for the propagators, carefully propagating uncertainties due to the fit procedure and taking into account all possible correlations. Applying this procedure systematically to the gluon-propagator data, we observe the presence of a pair of complex poles at $p_{\mathrm{pole}}^2=(-0.37\pm 0.05_{\mathrm{stat}}\pm 0.08_{\mathrm{sys}})\pm i(0.66\pm 0.03_{\mathrm{stat}}\pm 0.02_{\mathrm{sys}}){\mathrm{GeV}}^2$, where ``stat'' represents the statistical error and ``sys'' the systematic one. We also find a zero on the negative real axis of $p^2$, at $p_{\mathrm{zero}}^2=(-2.9\pm 0.4_{\mathrm{stat}}\pm 0.9_{\mathrm{sys}}){\mathrm{GeV}}^2$. We thus note that our procedure -- which is based on a model-independent approach and includes careful error propagation -- confirms the presence of a pair of complex poles in the gluon propagator, in agreement with previous works. For the ghost propagator, the Padés indicate the existence of the single pole at $p^2=0$, as expected. We also find evidence of a branch cut on the negative real axis. Through the use of the so-called D-Log Padé method, which is designed to approximate functions with cuts, we corroborate the existence of this cut for the ghost propagator.

    ↳ hep-lathep-phPoS(2023)·0 citations
39. 39*

    Patterns of gauge symmetry in the background field method

    A. C. Aguilar🇧🇷 · M. N. Ferreira🇪🇸 · D. Ibañez🇪🇸 · B. M. Oliveira🇧🇷 · J. Papavassiliou🇪🇸

    The correlation functions of Yang-Mills theories formulated in the background field method satisfy linear Slavnov-Taylor identities, which are naive generalizations of simple tree level relations, with no deformations originating from the ghost sector of the theory. In recent years, a stronger version of these identities has been found to hold at the level of the background gluon self-energy, whose transversality is enforced separately for each special block of diagrams contributing to the gluon Schwinger-Dyson equation. In the present work we demonstrate by means of explicit calculations that the same distinct realization of the Slavnov-Taylor identity persists in the case of the background three-gluon vertex. The analysis is carried out at the level of the exact Schwinger-Dyson equation for this vertex, with no truncations or simplifying assumptions. The demonstration entails the contraction of individual vertex diagrams by the relevant momentum, which activates Slavnov-Taylor identities of vertices and multi-particle kernels nested inside these graphs; the final result emerges by virtue of a multitude of extensive cancellations, without the need of performing explicit integrations. In addition, we point out that background Ward identities amount to replacing derivatives of propagators by zero-momentum background-gluon insertions, in exact analogy to standard properties of Abelian gauge theories. Finally, certain potential applications of these results are briefly discussed.

    ↳ hep-thhep-lathep-phnucl-thEPJC(2023)·3 citations
40. 40*

    Vector meson photoproduction in UPCs with FoCal

    Alexander Bylinkin🇳🇴 · Joakim Nystrand🇳🇴 · Daniel Tapia Takaki🇺🇸

    We discuss the physics prospects of photon-induced measurements using the high-granularity FoCal detector to be installed at the ALICE experiment, covering the pseudorapidity interval $3.4\le \eta \le 5.8$. This new detector, scheduled to be in operation from Run 4, will explore the small Bjorken-$x$ physics region in an unprecedented way. In this region the gluon saturation phenomenon is expected to be dominant. Combined with the rest of the ALICE subdetectors, including the zero degree calorimenters, FoCal will serve to reconstruct in a model-independent way the measured photoproduction cross sections for vectors mesons in a wide range of photon-target energies, down to $x$ values of about $7\times 10^{-6}$ and $2\times 10^{-6}$ in ultra-peripheral photon--proton and photon--lead collisions, respectively.

    ↳ nucl-exhep-phphysics.ins-detJ.Phys.G(2023)·20 citations
41. 41*

    A machine learning approach to the classification of phase transitions in many flavor QCD

    Frithjof Karsch🇩🇪 · Anirban Lahiri🇩🇪 · Marius Neumann🇩🇪 · Christian Schmidt🇩🇪

    Normalizing flows are generative machine learning models which can efficiently approximate probability distributions, using only given samples of a distribution. This architecture is used to interpolate the chiral condensate obtained from QCD simulations with five degenerate quark flavors in the HISQ action. From this a model for the probability distribution of the chiral condensate as function of lattice volume, quark mass and gauge coupling is obtained. Using the model, first order and crossover regions can be classified and the boundary between these regions can be marked by a critical mass. An extension of this model to studies of phase transitions in QCD with variable number of flavors is expected to be possible.

    ↳ hep-lathep-phPoS(2023)·9 citations
42. 42*

    The 3D structure of anisotropic flow in small collision systems at the Relativistic Heavy Ion Collider

    Wenbin Zhao🇺🇸 · Sangwook Ryu🇺🇸 · Chun Shen🇺🇸 · Björn Schenke🇺🇸

    We present (3+1)D dynamical simulations of asymmetric nuclear collisions at the Relativistic Heavy Ion Collider (RHIC). Employing a dynamical initial state model coupled to (3+1)D viscous relativistic hydrodynamics, we explore the rapidity dependence of anisotropic flow in the RHIC small system scan at 200 GeV center of mass energy. We calibrate parameters to describe central ${}^3$He+Au collisions and make extrapolations to d+Au and p+Au collisions. Our calculations demonstrate that approximately 50% of the $v_3(p_T)$ difference between the measurements by the STAR and PHENIX Collaborations can be explained by the use of reference flow vectors from different rapidity regions. This emphasizes the importance of longitudinal flow decorrelation for anisotropic flow measurements in asymmetric nuclear collisions, and the need for (3+1)D simulations. We also present results for the beam energy dependence of particle spectra and anisotropic flow in d+Au collisions.

    ↳ nucl-thhep-phnucl-exPRC(2023)·60 citations
43. 43*

    Probing initial baryon stopping and equation of state with rapidity-dependent directed flow of identified particles

    Lipei Du🇨🇦 · Chun Shen🇺🇸 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

    Using a (3+1)-dimensional hybrid framework with parametric initial conditions, we study the rapidity-dependent directed flow $v_1(y)$ of identified particles, including pions, kaons, protons, and lambdas in heavy-ion collisions. Cases involving Au+Au collisions are considered, performed at $\sqrt{s_{\mathrm{NN}}}$ ranging from 7.7 to 200 GeV. The dynamics in the beam direction is constrained using the measured pseudo-rapidity distribution of charged particles and the net proton rapidity distribution. Within this framework, the directed flow of mesons is driven by the sideward pressure gradient from the tilted source, and that of baryons mainly due to the initial asymmetric baryon distribution with respect to the beam axis driven by the transverse expansion. Our approach successfully reproduces the rapidity- and beam energy-dependence of $v_1$ for both mesons and baryons. We find that the $v_1(y)$ of baryons has strong constraining power on the initial baryon stopping, and together with that of mesons, the directed flow probes the equation of state of the dense nuclear matter at finite chemical potentials.

    ↳ nucl-thhep-phnucl-exPRC(2023)·42 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.