Thu·Jun 3, 2021Thursday·June 3, 2021

1. 01*

   Theoretical description of the plaquette with exponential accuracy

   Antonio Pineda🇪🇸

   We review recent studies of the operator product expansion of the plaquette and of the associated determination of the gluon condensate. One first needs the perturbative expansion to orders high enough to reach the asymptotic regime where the renormalon behavior sets in. The divergent perturbative series is formally regulated using the principal value prescription for its Borel integral. Subtracting the perturbative series truncated at the minimal term, we obtain the leading non-perturbative correction of the operator product expansion, i.e. the gluon condensate, with superasymptotic accuracy. It is then explored how to increase such precision within the context of the hyperasymptotic expansion. The results fully confirm expectations from renormalons and the operator product expansion.

   hep-phhep-lathep-thEur.Phys.J.ST(2021)·1 citation
2. 02*

   Electroproduction of heavy vector mesons using holographic QCD: from near threshold to high energy regimes

   Kiminad A. Mamo🇺🇸 · Ismail Zahed🇺🇸

   We develop a non-perturbative analysis of the electro-production of heavy vector mesons ($\varphi$, $J/\Psi$) from threshold to high energy. We use the holographic construction with bulk confinement enforced through a soft wall. Using Witten diagrams, we evaluate the pertinent cross sections for heavy vector mesons ($\varphi$, $J/\Psi$) production and study their dependence on both the incoming virtual photon polarization as well as the outgoing polarization of the heavy meson. Our results for $J/\Psi$ electro-production compares well with the available HERA data at low and intermediate $Q^2$, and for a wide range of momentum transfer. We also predict the quasi-real electro-production of $J/\Psi$ near threshold.

   hep-phhep-exhep-thnucl-ex+1PRD(2021)·25 citations
3. 03*

   Electromagnetic radii of the nucleon in soft-wall holographic QCD

   Kiminad A. Mamo🇺🇸 · Ismail Zahed🇺🇸

   We revisit the electromagnetic form factors of the proton and neutron in the original-minimal soft-wall holographic QCD, which has only two parameters, i.e., the mass scale $\kappa$ and the twist parameter of the nucleon $\tau$. We first fix $\tau =3$ by the hard scattering rule, and extract $\kappa =0.402\text{GeV}$ from the world data (including the Mainz A1 data) of the Sachs magnetic form factor of the proton $G_M^p$. We then predict among others, the charge radius of the proton to be ${\mathbf{r}}_{\mathbf{p}}=0.831\pm 0.008\text{fm}$, in perfect agreement with the recent charge radius of the proton measured by the PRad collaboration at Jefferson Lab, and in agreement with the muonic hydrogen experiments. Our prediction for the proton elastic form factor ratio ${\mu }_p{G}_E^p/G_M^p$ is also in very good agreement with the recent high precision Jefferson Lab recoil polarization experiment E08-007 for $Q^2=0.3-0.6{\text{GeV}}^2$, and with the recent high precision Mainz A1 experiment for $Q^2<0.13{\text{GeV}}^2$.

   hep-phhep-exhep-thnucl-ex+1NPB(2023)·18 citations
4. 04*

   SiD Simulation & Analysis for ILC Snowmass Physics LoIs

   Chris Potter🇺🇸

   The correct modeling of $e^{+}{e}^{-}$ collision events at the International Linear Collider (ILC), as well as the response of a collider detector like the Silicon Detector (SiD), is crucial to evaluating the expected sensitivity to key properties of the Higgs boson. In this document we describe the event generation and detector simulation in use for the SiD Letters of Interest submitted for the 2021 Snowmass community planning exercise.

   hep-phphysics.ins-det3 citations
5. 05*

   The Standard Model of particle physics as a conspiracy theory and the possible role of the Higgs boson in the evolution of the early universe

   Fred Jegerlehner🇩🇪

   I am considering Veltman's "The Infrared - Ultraviolet Connection" addressing the issue of quadratic divergences and the related huge radiative correction predicted by the electroweak Standard Model (SM) in the relationship between the bare and the renormalized theory, commonly called "the hierarchy problem" which usually is claimed that this has to be cured. After the discovery of the Higgs particle at CERN, which essentially completed the SM, an amazing interrelation of the leading interaction strengths of the gauge bosons, the top-quark and the Higgs boson showed up amounting that the SM allows for a perturbative extrapolation of the running couplings up to the Planck scale. The central question concerns the stability of the electroweak vacuum, which requires that the running Higgs self-coupling stays positive. Although several evaluations seem to favor the meta-stability within the experimental and theoretical parameter-uncertainties, one should not exclude the possibility that other experiments and improved matching conditions will be able to establish the absolute stability of the SM vacuum in the future. I will discuss the stable vacuum scenario and its impact on early cosmology, revealing the Higgs boson as the inflaton. It turns out that the Standard Model's presumed "hierarchy problem" and similarly the "cosmological constant problem" resolve themselves when we understand the SM as a low energy effective tail that is emergent from a cutoff-medium at the Planck scale. "The Infrared - Ultraviolet Connection" conveyed by the Higgs boson mass renormalization appears in a new light when the energy dependence of the SM couplings is taken into account. The bare Higgs boson mass square then changes sign below the Planck scale where it is activating the Higgs mechanism.

   hep-phActa Phys.Polon.B(2021)·18 citations
6. 06*

   The axial charges of proton within an extended chiral constituent quark model

   Jin-Bao Wang🇨🇳 · Gang Li🇨🇳 · Chun-Sheng An🇨🇳 · Ju-Jun Xie🇨🇳

   We have performed a study of the isovector, octet and singlet axial charges of the proton in an extended chiral constituent quark model, where all the possible $uudq\bar{q}$~($q=u,d,s$) five-quark Fock components in the proton wave function are taken into account. The ${}^3{P}_0$ quark-antiquark creation mechanism is assumed to account for the transition coupling between three- and five-quark components in proton, and the corresponding transition coupling strength is fixed by fitting the intrinsic sea flavor asymmetry $\bar{d}-\bar{u}$ data for proton. Accordingly, with all the parameters fixed by empirical values, the probabilities of the intrinsic five-quark Fock components in proton wave function should be $\sim 30-50\%$, which lead to the numerical results for quark spin $\Delta u$, $\Delta d$ and $\Delta s$, as well the axial charges of proton consistent with the experimental data and predictions by other theoretical approaches.

   hep-phPRD(2021)·6 citations
7. 07*

   Effect of the pion field on the distributions of pressure and shear in the proton

   Shiryo Owa🇦🇺 · A. W. Thomas🇦🇺 · X.G. Wang🇦🇺

   In light of recent experimental progress in determining the pressure and shear distributions in the proton, these quantities are calculated in a model with confined quarks supplemented by the pion field required by chiral symmetry. The incorporation of the pion contributions is shown to account for the long-range distributions, in general agreement with the experimentally extracted quark contributions. The results of the model are also compared with lattice QCD results at unphysically large quark mass.

   hep-phhep-exhep-latnucl-thPLB(2022)·14 citations
8. 08*

   Bottomonia production in p+p collisions under NRQCD formalism

   Vineet Kumar🇮🇳 · Kinkar Saha🇮🇳 · Prashant Shukla🇮🇳 · Abhijit Bhattacharyya🇮🇳

   In this work, we present the calculation of the production cross sections of bottomonia states using Non-Relativistic Quantum Chromodynamics (NRQCD) formalism. The direct production cross-section of a resonance can be factorised in terms of short distance Quantum Chromodynamics (QCD) cross sections and long distance matrix elements (LDMEs) under NRQCD. We use a large set of measured ${\rm Y}$(nS) production data at Tevatron and LHC energies in both central and forward rapidity regions to extract the LDMEs with better precision. The feed down contributions from the higher states including the ${\chi }_b$(3P) state are taken into account for the LDME extraction. The formalism provides a good description of the bottomonia data in wide transverse momentum range at different collision energies.

   hep-phhep-exhep-latnucl-thNPA(2021)·1 citation
9. 09*

   The Self-energy of Nucleon for the Photon-proton Elastic Scattering and the Electromagnetic Polarizability

   Susumu Kinpara🇯🇵

   The effect of the self-energy on the photon-proton elastic scattering is investigated for the backward and the forward directions. The shape of the Thomson scattering at the photon energy $\omega \to 0$ is broken by taking into account the self-energy of proton. The electromagnetic polarizabilities $\bar{\alpha }\pm \bar{\beta }$ are calculated by the lowest-order perturbative treatment.

   hep-phnucl-th1 citation
10. 10*

    Magnetic Moments of Leptons, Charged Lepton Flavor Violations and Dark Matter Phenomenology of a Minimal Radiative Dirac Neutrino Mass Model

    Bibhabasu De (IOP Bhubaneswar)🇮🇳 · Debottam Das (IOP Bhubaneswar)🇮🇳 · Manimala Mitra (IOP Bhubaneswar)🇮🇳 · Nirakar Sahoo (Utkal University)🇮🇳

    In a simple extension of the standard model (SM), a pair of vector like lepton doublets ($L_1$ and $L_2$) and a $SU(2{)}_L$ scalar doublet ($\eta$) have been introduced to help in accommodating the discrepancy in determination of the anomalous magnetic moments of the light leptons, namely, $e$ and $\mu$. Moreover, to make our scenario friendly to a Dirac like neutrino and also for a consistent dark matter phenomenology, we specifically add a singlet scalar ($S$) and a singlet fermion ($\psi$) in the set-up. However, the singlet states also induce a meaningful contribution in other charged lepton processes. A discrete symmetry ${\mathcal{Z}}_2\times {\mathcal{Z}}_2^{\prime }$ has been imposed under which all the SM particles are even while the new particles may be assumed to have odd charges. In a bottom-up approach, with a minimal particle content, we systematically explore the available parameter space in terms of couplings and masses of the new particles. Here a number of observables associated with the SM leptons have been considered, e.g., masses and mixings of neutrinos, $(g-2)$ anomalies of $e$, $\mu$, charged lepton flavor violating (cLFV) observables and the dark matter (DM) phenomenology of a singlet-doublet dark matter. Neutrinos, promoted as the Dirac type states, acquire mass at one loop level after the discrete ${\mathcal{Z}}_2^{\prime }$ symmetry gets softly broken, while the unbroken ${\mathcal{Z}}_2$ keeps the dark matter stable. The mixing between the singlet $\psi$ and the doublet vector lepton can be constrained to satisfy the electroweak precision observables and the spin independent (SI) direct detection (DD) cross section of the dark matter. In this analysis, potentially important LHC bounds have also been discussed.

    hep-phJHEP(2022)·22 citations
11. 11*

    Photon decay in UHE air showers: stringent bound on Lorentz violation

    Fabian Duenkel🇩🇪 · Marcus Niechciol🇩🇪 · Markus Risse🇩🇪

    In extensive air showers induced by ultra-high-energy (UHE) cosmic rays, secondary photons are expected to be produced at energies far above those accessible by other means. It has been shown that the decay of such photons, as possible in certain theories allowing Lorentz violation, can lead to significant changes of the shower development. Based on observations of the average depth of the shower maximum $⟨X_{\text{max}}⟩$, a stringent bound on Lorentz violation has been placed in a previous work. Here we include the shower-to-shower fluctuations $\sigma (X_{\text{max}})$ as an additional observable. The combined comparison of $⟨X_{\text{max}}⟩$ and $\sigma (X_{\text{max}})$ to shower observations allows a much stricter test of the possible decay of UHE photons, improving the previous bound by a factor of 50.

    hep-phastro-ph.HEPRD(2021)·27 citations
12. 12*

    In-medium kinetic theory of $D$ mesons and heavy-flavor transport coefficients

    Juan M. Torres-Rincon🇩🇪 · Glòria Montaña🇪🇸 · Àngels Ramos🇪🇸 · Laura Tolos🇪🇸

    We extend the kinetic theory of $D$ mesons to accommodate thermal and off-shell effects due to the medium modification of the heavy-meson spectral functions. From the Kadanoff-Baym approach we derive the off-shell Fokker-Planck equation which encodes the heavy-flavor transport coefficients. We analyze the thermal width (damping rate) of $D$ mesons due to their scattering off light mesons, focusing on new in-medium effects: off-shell corrections, inelastic channels, and the contribution of the Landau cut. We obtain that the latter effect (absent for vacuum scattering amplitudes) brings sizable corrections at moderate temperatures. We discuss how the heavy-flavor transport coefficients, like the drag and diffusion coefficients, are modified in matter. We find that the $D$-meson spatial diffusion coefficient matches smoothly to the latest results of lattice-QCD calculations and Bayesian analyses at higher temperatures.

    hep-phnucl-thPRC(2022)·24 citations
13. 13*

    The bosonic algebraic approach applied to the $[QQ][\bar{Q}\bar{Q}]$ tetraquarks

    A. J. Majarshin🇨🇳 · Yan-An Luo🇨🇳 · Feng Pan🇨🇳 · Jorge Segovia🇪🇸

    The exact eigenenergies of the $T_{4c}=[cc][\bar{c}\bar{c}]$, $T_{4b}=[bb][\bar{b}\bar{b}]$, and $T_{2[bc]}=[bc][\bar{b}\bar{c}]$ tetraquarks are calculated within the extended transitional Hamiltonian approach, in which the so-called Bethe \emph{ansatz} within an infinite-dimensional Lie algebra is used. We fit the parameters appearing in the transitional region from phenomenology associated with potential candidates of tetraquarks. The rotation and vibration transitional theory seems to provide a better description of heavy tetraquarks than other attempts within the same formalism. Our results indicate that the pairing strengths are large enough to provide binding; an extended comparison with the current literature is also performed.

    hep-phhep-exhep-latnucl-ex+1PRD(2022)·17 citations
14. 14*

    Renormalons in static QCD potential: review and some updates

    Hiromasa Takaura🇯🇵

    We give a brief review of the current understanding of renormalons of the static QCD potential in coordinate and momentum spaces. We also reconsider estimate of the normalization constant of the $u=3/2$ renormalon and propose a new way to improve the estimate.

    hep-phEur.Phys.J.ST(2021)·3 citations
15. 15*

    Neutrino events within muon bundles at neutrino telescopes

    Miguel Gutiérrez🇪🇸 · Gerardo Hernández-Tomé🇪🇸 · José I. Illana🇪🇸 · Manuel Masip🇪🇸

    The atmospheric neutrino flux includes a component from the prompt decay of charmed hadrons that becomes significant only at $E\ge 10$ TeV. At these energies, however, the diffuse flux of cosmic neutrinos discovered by IceCube seems to be larger than the atmospheric one. Here we study the possibility to detect a neutrino interaction in down-going atmospheric events at km${}^3$ telescopes. The neutrino signal will always appear together with a muon bundle that reveals its atmospheric origin and, generically, it implies an increase in the detector activity with the slant depth. We propose a simple algorithm that could separate these events from regular muon bundles.

    hep-phastro-ph.HEAstropart.Phys.(2022)·3 citations
16. 16*

    Accessing quark GPDs in diffractive events at an electron-ion collider

    W. Cosyn🇺🇸 · B. Pire🇫🇷 · L. Szymanowski🇵🇱

    We discuss two collider processes which combine a diffractively produced $\rho$ meson separated by a large rapidity gap from a hard exclusive scattering of a Pomeron on a nucleon, giving rise to a lepton pair or to a second meson. These two processes probe the nucleon quark content described by generalized parton distributions in a very specific way.

    hep-phhep-exnucl-exSciPost Phys.Proc.(2022)·2 citations
17. 17*

    Study of semi-boosted top quark reconstruction performance on the line shape of a $t\bar{t}$ resonance

    J. Pácalt🇨🇿 · J. Kvita🇨🇿

    We study the top quark pair events production in $pp$ collisions in the $\ell$+jets channel at the LHC energy of $\sqrt{s}=14$ TeV for Standard Model as well as new physics processes. We explore the usage of semi-boosted topologies where the top quark decays into a boosted hadronic $W$-jet and an isolated $b$-jet and study their performance in the $t\bar{t}$ events kinematic reconstruction. An efficiency increase is observed and the correlation of selected kinematic variables between the detector and particle level is studied. Quality of the reconstructed mass line shape of a $Z^{\prime }$ model with applications in current LHC experiments is evaluated. The results of the unfolding procedure for chosen spectra and an explicit proof of a slight degradation in the signal significance after the unfolding procedure are presented using the Fully Bayesian unfolding technique.

    hep-phhep-exInt.J.Mod.Phys.A(2022)·1 citation
18. 18*

    Estimating $ZZ$ production with $Z\gamma$ events at the LHC: cross-section ratio and uncertainties

    Jorge Sabater Iglesias🇩🇪 · Vincent Goumarre🇩🇪 · Fang-Ying Tsai🇺🇸 · Mangesh Sonawane🇦🇹 · Sarah Heim🇩🇪 · Beate Heinemann🇩🇪

    Standard Model $ZZ$ production is an important background for many searches at the LHC, especially in final states with missing transverse momentum. In this article, boson substitution is applied to estimate $ZZ\to {\ell }^{+}{\ell }^{-}\nu \bar{\nu }$ yields from $Z\gamma \to {\ell }^{+}{\ell }^{-}\gamma$ events. The cross-section ratio of the two processes and its uncertainties are evaluated at NNLO with the MATRIX generator as a function of the transverse momentum of the substituted boson. Uncertainties due to higher-order QCD corrections, parton distribution functions, photon isolation criteria, and electroweak corrections are evaluated. They depend strongly on the applied event selections and the considered transverse momentum range. For minimal selections, their size is 3$-$4%, dominated by QCD-related uncertainties for transverse momenta below 500 GeV and by uncertainties due to the factorization of QCD and electroweak corrections at higher transverse momenta.

    hep-phhep-ex1 citation
19. 19*

    Beautiful and charming chromodipole moments

    Ulrich Haisch🇩🇪 · Gabriël Koole🇩🇪

    In the context of the Standard Model effective field theory we derive direct and indirect bounds on chromodipole operators involving the bottom and charm quark. We find that the experimental upper limit on the neutron electric dipole moment puts severe constraints on the imaginary parts of the Wilson coefficients of both chromodipole operators. The magnitudes of the Wilson coefficients are instead only weakly constrained by dijet searches and Z-boson production in association with bottom-quark jets. Flavour physics does not provide meaningful bounds.

    hep-phhep-exJHEP(2021)·23 citations
20. 20*

    Search for a light $Z^{\prime }$ at LHC in a neutrinophilic $U(1)$ model

    Waleed Abdallah🇪🇬 · Anjan Kumar Barik🇮🇳 · Santosh Kumar Rai🇮🇳 · Tousik Samui🇮🇳

    We consider a neutrinophilic $U(1)$ extension of the standard model (SM) which couples only to SM isosinglet neutral fermions, charged under the new group. The neutral fermions couple to the SM matter fields through Yukawa interactions. The neutrinos in the model get their masses from a standard inverse-seesaw mechanism while an added scalar sector is responsible for the breaking of the gauged $U(1)$ leading to a light neutral gauge boson ($Z^{\prime }$), which has minimal interaction with the SM sector. We study the phenomenology of having such a light $Z^{\prime }$ in the context of neutrinophilic interactions as well as the role of allowing kinetic mixing between the new $U(1)$ group with the SM hypercharge group. We show that current experimental searches allow for a very light $Z^{\prime }$ if it does not couple to SM fields directly and highlight the search strategies at the LHC. We observe that multilepton final states in the form of $(4\ell +\text{slashed}{E}_T)$ and $(3\ell +2j+\text{slashed}{E}_T)$ could be crucial in discovering such a neutrinophilic gauge boson lying in a mass range of $200$--$500$ GeV.

    hep-phhep-exPRD(2021)·17 citations
21. 21*

    Naturalness and the muon magnetic moment

    Nima Arkani-Hamed🇺🇸 · Keisuke Harigaya🇺🇸

    We study a predictive model for explaining the apparent deviation of the muon anomalous magnetic moment from the Standard Model expectation. There are no new scalars and hence no new hierarchy puzzles beyond those associated with the Higgs; the only new particles at the TeV scale are vector-like singlet and doublet leptons. Interestingly, this simple model provides a calculable example violating the Wilsonian notion of naturalness: despite the absence of any symmetries prohibiting its generation, the coefficient of the naively leading dimension-six operator for $(g-2)$ vanishes at one-loop. While effective field theorists interpret this either as a surprising UV cancellation of power divergences, or as a delicate cancellation between matching UV and calculable IR corrections to $(g-2)$ from parametrically separated scales, there is a simple explanation in the full theory: the loop integrand is a total derivative of a function vanishing in both the deep UV and IR. The leading contribution to $(g-2)$ arises from dimension-eight operators, and thus the required masses of new fermions are lower than naively expected, with a sizeable portion of parameter space already covered by direct searches at the LHC. The viable parameter space free of fine-tuning for the muon mass will be fully covered by future direct LHC searches, and {\it all} of the parameter space can be probed by precision measurements at planned future lepton colliders.

    hep-phhep-thJHEP(2021)·51 citations
22. 22*

    Testing Bell inequalities in Higgs boson decays

    Alan Barr🇬🇧

    Higgs boson decays produce pairs of $W$ bosons in a maximally entangled state, the spins of which can be expected to violate Bell inequalities. We show that the spin density matrix of the $W^{\pm }$ pair may be reconstructed experimentally from the directions of the charged lepton decay products, and from it the expectation values of various Bell operators determined. Numerical simulations of $H\to W{W}^{\ast }$ decays indicate that violation of a generalised CHSH inequality is unlikely to be measurable, however the CGLMP inequality is near-maximally violated. Experimental Bell tests could be performed at a variety of colliders and in different production channels. If reconstruction effects and backgrounds can be controlled then statistically significant violations could be observable even with datasets comparable to those already collected at the LHC.

    hep-phhep-exquant-phPLB(2022)·139 citations
23. 23*

    Next-to-Next-to-Leading-Order QCD Prediction for the Photon-Pion Form Factor

    Jing Gao🇨🇳 · Tobias Huber🇩🇪 · Yao Ji🇩🇪 · Yu-Ming Wang🇨🇳

    We accomplish the complete two-loop computation of the leading-twist contribution to the photon-pion transition form factor $\gamma {\gamma }^{\ast }\to {\pi }^0$ by applying the hard-collinear factorization theorem together with modern multi-loop techniques. The resulting predictions for the form factor indicate that the two-loop perturbative correction is numerically important. We also demonstrate that our results will play a key role in disentangling various models of the twist-two pion distribution amplitude thanks to the envisaged precision at Belle II.

    hep-phPRL(2022)·44 citations
24. 24*

    Vector Boson Scattering Processes: Status and Prospects

    Diogo Buarque Franzosi🇸🇪 · Michele Gallinaro🇵🇹 · Richard Ruiz🇵🇱 · Thea K. Aarrestad🇨🇭 · Flavia Cetorelli🇮🇹 · Mauro Chiesa🇮🇹 · Antonio Costantini🇧🇪 · Ansgar Denner🇩🇪 · Stefan Dittmaier🇩🇪 · Robert Franken🇩🇪 · Pietro Govoni🇮🇹 · Tao Han🇺🇸 and 17 other authors

    Insight into the electroweak (EW) and Higgs sectors can be achieved through measurements of vector boson scattering (VBS) processes. The scattering of EW bosons are rare processes that are precisely predicted in the Standard Model (SM) and are closely related to the Higgs mechanism. Modifications to VBS processes are also predicted in models of physics beyond the SM (BSM), for example through changes to the Higgs boson couplings to gauge bosons and the resonant production of new particles. In this review, experimental results and theoretical developments of VBS at the Large Hadron Collider, its high luminosity upgrade, and future colliders are presented.

    hep-phhep-exRev.Phys.(2022)·56 citations
25. 25*

    Latent Space Refinement for Deep Generative Models

    Ramon Winterhalder🇧🇪 · Marco Bellagente🇩🇪 · Benjamin Nachman🇺🇸

    Deep generative models are becoming widely used across science and industry for a variety of purposes. A common challenge is achieving a precise implicit or explicit representation of the data probability density. Recent proposals have suggested using classifier weights to refine the learned density of deep generative models. We extend this idea to all types of generative models and show how latent space refinement via iterated generative modeling can circumvent topological obstructions and improve precision. This methodology also applies to cases were the target model is non-differentiable and has many internal latent dimensions which must be marginalized over before refinement. We demonstrate our Latent Space Refinement (LaSeR) protocol on a variety of examples, focusing on the combinations of Normalizing Flows and Generative Adversarial Networks.

    ↳ stat.MLcs.LGhep-exhep-ph+1NeurIPS DGMs and Applications Workshop 20…·33 citations
26. 26*

    Complex Analysis of Askaryan Radiation: A Fully Analytic Model in the Time-Domain

    Jordan C. Hanson🇺🇸 · Raymond Hartig🇺🇸

    The detection of ultra-high energy (UHE, >10 PeV) neutrinos via detectors designed to utilize the Askaryan effect has been a long-time goal of the astroparticle physics community. The Askaryan effect describes radio-frequency (RF) radiation from high-energy cascades. When a UHE neutrino initiates a cascade, cascade properties are imprinted on the radiation. Thus, observed radiation properties must be used to reconstruct the UHE neutrino event. Analytic Askaryan models have three advantages when used for UHE neutrino reconstruction. First, cascade properties may be derived from the match between analytic function and observed data. Second, analytic models minimize computational intensity in simulation packages. Third, analytic models can be embedded in firmware to enhance the real-time sensitivity of detectors. We present a fully analytic Askaryan model in the time-domain for UHE neutrino-induced cascades in dense media that builds upon prior models in the genre. We then show that our model matches semi-analytic parameterizations used in Monte Carlo simulations for the design of IceCube-Gen2. We find correlation coefficients greater than 0.95 and fractional power differences < 5% between the the fully analytic and semi-analytic approaches.

    ↳ astro-ph.HEhep-phPRD(2022)·2 citations
27. 27*

    Gibbs entropy from entanglement in electric quenches

    Adrien Florio🇺🇸 · Dmitri E. Kharzeev🇺🇸

    In quantum electrodynamics with charged fermions, a background electric field is the source of the chiral anomaly which creates a chirally imbalanced state of fermions. This chiral state is realized through the production of entangled pairs of right-moving fermions and left-moving antifermions (or vice versa, depending on the orientation of the electric field). Here we show that the statistical Gibbs entropy associated with these pairs is equal to the entropy of entanglement between the right-moving particles and left-moving antiparticles. We then derive an asymptotic expansion for the entanglement entropy in terms of the cumulants of the multiplicity distribution of produced particles and explain how to re-sum this asymptotic expansion. Finally, we study the time dependence of the entanglement entropy in a specific time-dependent pulsed background electric field, the so-called "Sauter pulse", and illustrate how our resummation method works in this specific case. We also find that short pulses (such as the ones created by high energy collisions) result in an approximately thermal distribution for the produced particles.

    ↳ hep-thhep-phnucl-thquant-phPRD(2021)·22 citations
28. 28*

    Evidence for the decay ${\Omega }_c^0\to {\pi }^{+}\Omega (2012{)}^{-}\to {\pi }^{+}(\bar{K}\Xi {)}^{-}$

    Belle Collaboration: Y. Li🇨🇳 · S. S. Tang🇨🇳 · S. Jia🇨🇳 · C. P. Shen🇨🇳 · I. Adachi🇯🇵 · H. Aihara🇯🇵 · S. Al Said🇸🇦 · D. M. Asner🇺🇸 · H. Atmacan🇺🇸 · V. Aulchenko🇷🇺 · T. Aushev🇷🇺 · R. Ayad🇸🇦 and 180 other authors

    Using a data sample of 980~fb${}^{-1}$ collected with the Belle detector operating at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider, we present evidence for the $\Omega (2012{)}^{-}$ in the resonant substructure of ${\Omega }_c^0\to {\pi }^{+}(\bar{K}\Xi {)}^{-}$ ($(\bar{K}\Xi {)}^{-}$ = $K^{-}{\Xi }^0$ + ${\bar{K}}^0{\Xi }^{-}$) decays. The significance of the $\Omega (2012{)}^{-}$ signal is 4.2$\sigma$ after considering the systematic uncertainties. The ratio of the branching fraction of ${\Omega }_c^0\to {\pi }^{+}\Omega (2012{)}^{-}\to {\pi }^{+}(\bar{K}\Xi {)}^{-}$ relative to that of ${\Omega }_c^0\to {\pi }^{+}{\Omega }^{-}$ is calculated to be 0.220 $\pm$ 0.059(stat.) $\pm$ 0.035(syst.). The individual ratios of the branching fractions of the two isospin modes are also determined, and found to be $\mathcal{B}({\Omega }_c^0\to {\pi }^{+}\Omega (2012{)}^{-})\times \mathcal{B}(\Omega (2012{)}^{-}\to K^{-}{\Xi }^0)/\mathcal{B}({\Omega }_c^0\to {\pi }^{+}{K}^{-}{\Xi }^0)$ = (9.6 $\pm$ 3.2(stat.) $\pm$ 1.8(syst.))\% and $\mathcal{B}({\Omega }_c^0\to {\pi }^{+}\Omega (2012{)}^{-})\times \mathcal{B}(\Omega (2012{)}^{-}\to {\bar{K}}^0{\Xi }^{-})/\mathcal{B}({\Omega }_c^0\to {\pi }^{+}{\bar{K}}^0{\Xi }^{-})$ = (5.5 $\pm$ 2.8(stat.) $\pm$ 0.7(syst.))\%.

    ↳ hep-exhep-phPRD(2021)·25 citations
29. 29*

    Complex Field Inflation

    Ruopeng Zhang🇨🇳 · Sibo Zheng🇨🇳

    We report first study of complex field inflation. Although understood as a specific two-field inflation, a complex field inflation is able to make more robust model predictions on primordial curvature perturbation. Explicitly we discuss the model realizations of complex chaotic and exponential inflation in various large-field contexts. Both complex field models contain a single complex scalar together with only two free parameters. Using numerical handles aimed to calculate primordial curvature perturbation from multifield inflation, we show that both models are compatible with current Planck data, and the individual surviving parameter space can be substantially or fully probed by future CMB-S4 experiments.

    ↳ astro-ph.COhep-ph1 citation
30. 30*

    Testing the predictions of axisymmetric distribution functions of galactic dark matter with hydrodynamical simulations

    Mihael Petač🇮🇹 · Julien Lavalle🇫🇷 · Arturo Núñez-Castiñeyra🇫🇷 · Emmanuel Nezri🇫🇷

    Signal predictions for galactic dark matter (DM) searches often rely on assumptions on the DM phase-space distribution function (DF) in halos. This applies to both particle (e.g. $p$-wave suppressed or Sommerfeld-enhanced annihilation, scattering off atoms, etc.) and macroscopic DM candidates (e.g. microlensing of primordial black holes). As experiments and observations improve in precision, better assessing theoretical uncertainties becomes pressing in the prospect of deriving reliable constraints on DM candidates or trustworthy hints for detection. Most reliable predictions of DFs in halos are based on solving the steady-state collisionless Boltzmann equation (e.g. Eddington-like inversions, action-angle methods, etc.) consistently with observational constraints. One can do so starting from maximal symmetries and a minimal set of degrees of freedom, and then increasing complexity. Key issues are then whether adding complexity, which is computationally costy, improves predictions, and if so where to stop. Clues can be obtained by making predictions for zoomed-in hydrodynamical cosmological simulations in which one can access the true (coarse-grained) phase-space information. Here, we test an axisymmetric extension of the Eddington inversion to predict the full DM DF from its density profile and the total gravitational potential of the system. This permits to go beyond spherical symmetry, and is a priori well suited for spiral galaxies. We show that axisymmetry does not necessarily improve over spherical symmetry because the (observationally unconstrained) angular momentum of the DM halo is not generically aligned with the baryonic one. Theoretical errors are similar to those of the Eddington inversion though, at the 10-20% level for velocity-dependent predictions related to particle DM searches in spiral galaxies. We extensively describe the approach and comment on the results.

    ↳ astro-ph.COastro-ph.GAhep-exhep-phJCAP(2021)·3 citations
31. 31*

    Bootstrapping a Two-Loop Four-Point Form Factor

    Yuanhong Guo🇨🇳 · Lei Wang🇨🇳 · Gang Yang🇨🇳

    We compute the two-loop four-point form factor of a length-3 half-BPS operator in planar N=4 SYM, which belongs to the class of two-loop five-point scattering observables with one off-shell color-singlet leg. A new bootstrapping strategy is developed to obtain this result by starting with an ansatz expanded in terms of master integrals and then solving the master coefficients via various physical constraints. We find that consistency conditions of infrared divergences and collinear limits, together with the cancellation of spurious poles, can fix a significant part of the ansatz. The remaining degrees of freedom can be fixed by one simple type of two-double unitarity cut. Full analytic results in terms of both symbol and Goncharov polylogarithms are provided.

    ↳ hep-thhep-phPRL(2021)·29 citations
32. 32*

    Exploring black holes as particle accelerators: hoop-radius, target particles and escaping conditions

    Stefano Liberati🇮🇹 · Christian Pfeifer🇩🇪 · José Javier Relancio🇪🇸

    The possibility that rotating black holes could be natural particle accelerators has been subject of intense debate. While it appears that for extremal Kerr black holes arbitrarily high center of mass energies could be achieved, several works pointed out that both theoretical as well as astrophysical arguments would severely dampen the attainable energies. In this work we study particle collisions near Kerr black holes, by reviewing and extending the so far proposed scenarios. Most noticeably, we shall focus on the recently advanced target particle scenarios which were claimed to reach arbitrarily high energies even for Schwarzschild black holes. By implementing the hoop conjecture we show that these scenarios involving near-horizon target particles are in principle able to attain, sub-Planckian, but still ultra-high center of mass energies of the order of $10^{23}-10^{25}$ eV even for non-extremal Kerr black holes. Furthermore, analysing the properties of particles produced in such collisions, we find that photons can escape to infinity. However, their energy is only of the order of the energy of the colliding particles and hence relatively low, which is the same conclusion previously reached in the literature about the original Bañados--Silk--West process. This finding points towards a general limitation of collisional Penrose processes, at least for what concerns their primary products.

    ↳ gr-qcastro-ph.HEhep-phJCAP(2022)·16 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.