Mon·Sep 23, 2019Monday·September 23, 2019

1. 01*

   Probing new physics using Rydberg states of atomic hydrogen

   Matthew P. A. Jones🇬🇧 · Robert M. Potvliege🇬🇧 · Michael Spannowsky🇬🇧

   We consider the role of high-lying Rydberg states of simple atomic systems such as ${}^1$H in setting constraints on physics beyond the Standard Model. We obtain highly accurate bound states energies for a hydrogen atom in the presence of an additional force carrier (the energy levels of the Hellmann potential). These results show that varying the size and shape of the Rydberg state by varying the quantum numbers provides a way to probe the range of new forces. By combining these results with the current state-of-the-art QED corrections, we determine a robust global constraint on new physics that includes all current spectroscopic data in hydrogen. Lastly we show that improved measurements that fully exploit modern cooling and trapping methods as well as higher-lying states could lead to a strong, statistically robust global constraint on new physics based on laboratory measurements only.

   hep-phhep-exphysics.atom-phPRResearch(2020)·45 citations
2. 02*

   Dark CP-violation through the $Z$-portal

   Venus Keus🇫🇮

   Despite great agreement with experiment, the Standard Model (SM) of particle physics lacks a viable Dark Matter (DM) candidate and sufficient amount of CP-violation to account for the observed baryon excess in the universe. Non-minimal Higgs frameworks are economic extensions of the SM which could remedy these shortcomings. Within the framework of a three Higgs doublet model, we introduce an extended dark sector which accommodates both DM and CP-violation. Such dark sources of CP-violation do not contribute to the Electric Dipole Moments and are therefore unconstrained. We present a novel mechanism in which the CP-violating dark particles only interact with the SM through the gauge bosons, primarily the $Z$ boson. Such $Z$-portal dark CP violation is realised in the regions of the parameter space where Higgs-mediated (co)annihilation processes are sub-dominant and have negligible contributions to the DM relic density. We show that such $Z$-portal CP violating DM can still thermalise and satisfy all experimental and observational bounds and discuss the implications of such phenomena for electroweak baryogenesis.

   hep-phPRD(2020)·19 citations
3. 03*

   CP violation for four generations of quarks

   Ubaldo Cavazos Olivas🇲🇽 · S. Rebeca Juárez Wysozka🇲🇽 · Piotr Kielanowski🇲🇽

   We discuss the generalization of the Jarlskog condition of CP conservation for the case of the Standard Model with 4~quark generations. We express this condition in terms of the 3 Jarlskog invariants of the CKM matrix. Next we present the test for the existence of the 4-th quark generation in terms of the Jarlskog invariants involving only known particles.

   hep-phInt.J.Mod.Phys.A(2020)·3 citations
4. 04*

   Reevaluating Reactor Antineutrino Anomalies with Updated Flux Predictions

   Jeffrey Berryman🇺🇸 · Patrick Huber🇺🇸

   Hints for the existence of a sterile neutrino at nuclear reactors are reexamined using two updated predictions for the fluxes of antineutrinos produced in fissions. These new predictions diverge in their preference for the rate deficit anomaly, relative to previous analyses, but the anomaly in the ratios of measured antineutrino spectra persists. We comment on upcoming experiments and their ability to probe the preferred region of the sterile-neutrino parameter space in the electron neutrino disappearance channel.

   hep-phhep-exnucl-exnucl-thPRD(2020)·39 citations
5. 05*

   The decay $J/\psi \to \gamma \varphi \varphi$: spin dependence of amplitude and angular distributions of photons with linear polarizations

   A.A. Kozhevnikov🇷🇺

   Based on the effective invariant amplitudes of the transitions $J/\psi \to \gamma X(J^P)$ and $X(J^P)\to \varphi \varphi$, the spin dependence of the $J/\psi \to \gamma X(J^P)\to \gamma \varphi \varphi$ decay amplitude is obtained in the case of the intermediate resonances $X$ with $J^P=0^{\pm },1^{\pm },2^{\pm }$. Angular distributions of photons with the definite linear polarizations relative to the plane spanned by the momentum of initial electron and the total momentum of the $\varphi \varphi$ pair in the reaction $e^{+}{e}^{-}\to J/\psi \to \gamma X(J^P)\to \gamma \varphi \varphi$ are calculated. It is shown that the sign of the asymmetry of the distributions of the photons polarized in the above plane and orthogonal to it correlates with the signature $P_X(-1{)}^{J_X}$ of the $X$ resonance with given spin-parity $J_X^{P_X}$ so it may help to establish this quantum number in a way which does not depend on the specific model of the $X(J^P)\to \varphi \varphi$ amplitude.

   hep-phhep-exnucl-thEPJA(2019)·3 citations
6. 06*

   Bounds on CP-violating Higgs-gluon interactions: the case of vanishing light-quark Yukawa couplings

   Ulrich Haisch🇩🇪 · Amando Hala🇩🇪

   We investigate CP-violating interactions involving the Higgs boson and gluons within an effective field theory approach, focusing on the specific class of new-physics scenarios where the Yukawa couplings of light quarks are zero or strongly suppressed compared to the standard-model expectations. We compute the contributions of the most relevant higher-dimensional operators of Weinberg type to the electric dipole moment of the neutron (nEDM), which are induced by Feynman diagrams that involve an effective CP-violating Higgs-gluon coupling and top-quark loops. The resulting nEDM sensitivities and prospects are discussed and compared to the existing and expected LHC bounds. We find that future nEDM searches can set non-trivial constraints on CP-violating Higgs-gluon interactions even if the Higgs only couples to the third generation of quarks.

   hep-phhep-exJHEP(2019)·17 citations
7. 07*

   Implications of the Dark LMA solution and Fourth Sterile Neutrino for Neutrino-less Double Beta Decay

   K. N. Deepthi🇮🇳 · Srubabati Goswami🇮🇳 · Vishnudath K. N. · Tanmay Kumar Poddar🇮🇳

   We analyze the effect of the Dark-large mixing angle (DLMA) solution on the effective Majorana mass ($m_{\beta \beta }$) governing neutrino-less double beta decay ($0\nu \beta \beta$) in the presence of a sterile neutrino. We consider the 3+1 picture, comprising of one additional sterile neutrino. We have checked that the MSW resonance in the sun can take place in the DLMA parameter space in this scenario. Next we investigate how the values of the solar mixing angle ${\theta }_{12}$ corresponding to the DLMA region alter the predictions of $m_{\beta \beta }$ including a sterile neutrino in the analysis. We also compare our results with three generation cases for both standard large mixing angle (LMA) and DLMA. Additionally, we evaluate the discovery sensitivity of the future ${}^{136}Xe$ experiments in this context.

   hep-phPRD(2020)·12 citations
8. 08*

   Moments of Angular Distribution in Two Mesons Photoproduction

   V. Mathieu🇪🇸

   The formalism devoted to the production of two pseudoscalar mesons with a linearly polarized photon beam has been detailed and illustrated in Phys. Rev. D100 (2019) 054017. This document reports the necessary formulas, without proof, to perform an analysis of the angular distribution of two mesons photoproduction. The relations to extract moments of the angular distribution are provided, as well as the relations between moments and partial waves for a system involving $S$, $P$ and $D$ waves. The expressions of the integrated beam asymmetry and the beam asymmetry along the $y$ axis in term of moments are mentioned.

   hep-phAIP Conf.Proc.(2020)·2 citations
9. 09*

   Solar Neutrino Limits on Decoherence

   Pedro Cunha de Holanda🇧🇷

   The solar neutrino flux arrives at Earth as an incoherent admixture of mass eigenstates, and then solar neutrino detection constitute a blind probe to the oscillation pattern of the neutrino flavour conversion. Consequently, it is also impossible to probe, in a model independent approach, any new physics that leads to an enhancement of decoherence during the neutrino evolution, an effect that is present for instance in Open Quantum System formalism. However, such mechanism can also induce changes between mass eigenstates if an energy interchange between the neutrino subsystem and the reservoir is not explicitly forbidden. In this work the conversion probabilities between mass eigenstates in an Open Quantum System are calculated, and limits are stablished for these kind of transitions. We present our results in a pedagogical way, pointing out how far the analysis can go without any assumption on the neutrino conversion physics inside the Sun, before performing the full calculations. We obtain as limits for the decoherence parameters the values of ${\Gamma }_3<6.5\times 10^{-19}$ eV and ${\Gamma }_8<7.1\times 10^{-19}$ eV at 3$\sigma$.

   hep-phJCAP(2020)·24 citations
10. 10*

    Searching for a Light Higgs Boson via the Yukawa Process at Lepton Colliders

    Eung Jin Chun🇰🇷 · Tanmoy Mondal🇰🇷

    We explore the prospect of Yukawa production of a light boson which can exist in an extended Higgs sector. A particularly interesting case is the light pseudoscalar in Type-X two Higgs doublet model which can explain the anomalous magnetic moment of muon at large $\tan \beta$. Considering ILC $Higgs$ $factory$ with $\sqrt{s}=250$ GeV, we show that the available parameter space can be fully examined by the (tau) Yukawa process at $5\sigma$. We also demonstrate the mass reconstruction of such a light particle which helps to sizably minimize the background events.

    hep-phhep-exPLB(2020)·20 citations
11. 11*

    SUSY-QCD corrected and Sommerfeld enhanced stau annihilation into heavy quarks with scheme and scale uncertainties

    J. Branahl🇩🇪 · J. Harz🇩🇪 · B. Herrmann🇫🇷 · M. Klasen🇩🇪 · K. Kovařík🇩🇪 · S. Schmiemann🇩🇪

    We investigate stau-antistau annihilation into heavy quarks in the phenomenological Minimal Supersymmetric Standard Model within the DM@NLO project. We present the calculation of the corresponding cross section including corrections up to $\mathcal{O}({\alpha }_s)$ and QED Sommerfeld enhancement. The numerical impact of these corrections is discussed for the cross section and the dark matter relic density, where we focus on top-quark final states and consider either neutralino or gravitino dark matter. Similarly to previous work, we find that the presented corrections should be included when calculating the relic density or extracting parameters from cosmological observations. Considering scheme and scale variations, we estimate the theoretical uncertainty that affects the prediction of the annihilation cross section and thus the prediction of the relic density.

    hep-phPRD(2019)·15 citations
12. 12*

    Double parton distributions in the pion in the Nambu and Jona-Lasinio model

    Aurore Courtoy🇲🇽 · Santiago Noguera🇪🇸 · Sergio Scopetta🇮🇹

    Two-parton correlations in the pion, a non perturbative information encoded in double parton distribution functions, are investigated in the Nambu and Jona-Lasinio model. It is found that double parton distribution functions expose novel dynamical information on the structure of the pion, not accessible through one-body parton distributions, as it happens in several estimates for the proton target and in a previous evaluation for the pion, in a light-cone framework. Expressions and predictions are given for double parton distributions corresponding to leading-twist Dirac operators in the quark vertices, and to different regularization methods for the Nambu and Jona-Lasinio model. These results are particularly relevant in view of forthcoming lattice data.

    hep-phJHEP(2019)·26 citations
13. 13*

    Fermion Mass and Mixing in a Low-Scale Seesaw Model based on the S4 Flavor Symmetry

    V. V. Vien🇻🇳 · H. N. Long🇻🇳 · A. E. Cárcamo Hernández🇨🇱

    We construct a low-scale seesaw model to generate the masses of active neutrinos based on $S_4$ flavor symmetry supplemented by the $Z_2\times Z_3\times Z_4\times Z_{14}\times U(1{)}_L$ group, capable of reproducing the low energy Standard model (SM) fermion flavor data. The masses of the SM fermions and the fermionic mixings parameters are generated from a Froggatt-Nielsen mechanism after the spontaneous breaking of the $S_4\times Z_2\times Z_3\times Z_4\times Z_{14}\times U(1{)}_L$ group. The obtained values for the physical observables of the quark and lepton sectors are in good agreement with the most recent experimental data. The leptonic Dirac CP violating phase ${\text{de}}_{CP}$ is predicted to be $259.579^{\circ }$ and the predictions for the absolute neutrino masses in the model can also saturate the recent constraints.

    hep-phPTEP(2019)·12 citations
14. 14*

    Explaining the MiniBooNE excess by a decaying sterile neutrino with mass in the 250 MeV range

    Oliver Fischer🇩🇪 · Alvaro Hernandez-Cabezudo🇩🇪 · Thomas Schwetz🇩🇪

    The MiniBooNE collaboration has reported an excess of $460.5\pm 95.8$ electron-like events ($4.8\sigma$). We propose an explanation of these events in terms of a sterile neutrino decaying into a photon and a light neutrino. The sterile neutrino has a mass around 250 MeV and it is produced from kaon decays in the proton beam target via mixing with the muon or the electron in the range $10^{-11}\lesssim |U_{\ell 4}{|}^2\lesssim 10^{-7}$ ($\ell =e,\mu$). The model can be tested by considering the time distribution of the events in MiniBooNE and by looking for single-photon events in running or upcoming neutrino experiments, in particular by the suite of liquid argon detectors in the short-baseline neutrino program at Fermilab.

    hep-phPRD(2020)·88 citations
15. 15*

    Dirac neutrino mass generation from Majorana messenger

    Julián Calle🇨🇴 · Diego Restrepo🇨🇴 · Óscar Zapata🇨🇴

    The radiative type-I seesaw has been already implemented to explain the lightness of Majorana neutrinos with both Majorana and Dirac heavy fermions, and the lightness of Dirac neutrinos with Dirac heavy fermions. In this work we present a minimal implementation of the radiative type-I seesaw with light Dirac neutrinos and heavy Majorana fermions. An inert doublet and a complex singlet scalar complete the dark sector which is protected by an Abelian fermiophobic gauge symmetry that also forbids tree level mass contributions for the full set of light neutrinos. A fermion vector-like extension of the model is also proposed where the light right-handed neutrinos can thermalize in the primordial plasma and the extra gauge boson can be directly produced at colliders. In particular, the current upper bound on $\Delta N_{\text{eff}}$ reported by PLANCK points to large ratios $M_{Z^{\prime }}/g^{\prime }\gtrsim 40\text{TeV}$ which can be competitive with collider constraint for $g^{\prime }$ sufficiently large in the ballpark of the Standard Model values, while future cosmic microwave background experiments may probe all the no minimal models presented here.

    hep-phPRD(2020)·24 citations
16. 16*

    Flavor structures of charged fermions and massive neutrinos

    Zhi-zhong Xing🇨🇳

    Most of the free parameters in the Standard Model (SM) -- a quantum field theory which has successfully elucidated the behaviors of strong, weak and electromagnetic interactions of all the known fundamental particles, come from the lepton and quark flavors. The discovery of neutrino oscillations has proved that the SM is incomplete, at least in its lepton sector; and thus the door of opportunity is opened to exploring new physics beyond the SM and solving a number of flavor puzzles. In this review article we give an overview of important progress made in understanding the mass spectra, flavor mixing patterns, CP-violating effects and underlying flavor structures of charged leptons, neutrinos and quarks in the past twenty years. After introducing the standard pictures of fermion mass generation, flavor mixing and CP violation in the SM extended with the presence of massive Dirac or Majorana neutrinos, we briefly summarize current experimental knowledge about the flavor parameters of quarks and leptons. Various ways of describing flavor mixing and CP violation are discussed, the renormalization-group evolution of flavor parameters is illuminated, and the matter effects on neutrino oscillations are interpreted. Taking account of possible extra neutrino species, we propose a standard parametrization of the $6\times 6$ flavor mixing matrix and comment on the phenomenological aspects of heavy, keV-scale and light sterile neutrinos. We pay particular attention to those novel and essentially model-independent ideas or approaches regarding how to determine the Yukawa textures of Dirac fermions and the effective mass matrix of Majorana neutrinos, including simple discrete and continuous flavor symmetries. An outlook to the future development in unravelling the mysteries of flavor structures is also given.

    hep-phhep-thnucl-thPhys.Rept.(2020)·338 citations
17. 17*

    Five-dimensional Supergravity in N = 1/2 Superspace

    Katrin Becker🇺🇸 · Melanie Becker🇩🇪 · Daniel Butter🇺🇸 · William D. Linch III🇺🇸 · Stephen Randall🇺🇸

    We construct 5D, N = 1 supergravity in a 4D, N = 1 superspace with an extra bosonic coordinate. This represents four of the supersymmetries and the associated Poincaré symmetries manifestly. The remaining four supersymmetries and the rest of the Poincaré symmetries are represented linearly but not manifestly. In the linearized approximation, the action reduces to the known superspace result. As an application of the formalism, we construct the $\int A\wedge R\wedge R$ invariant in this superspace.

    ↳ hep-thhep-phJHEP(2020)·4 citations
18. 18*

    Large- and Medium-Scale Anisotropies in the Arrival Directions of Cosmic Rays observed with KASCADE-Grande

    Markus Ahlers🇩🇰

    We search for anisotropies in the arrival directions of cosmic rays observed by the KASCADE-Grande air shower experiment. The analysis is based on public data of about 23.7 million events with reconstructed primary energies above 1 PeV. We apply a novel maximum-likelihood reconstruction method for the cosmic ray anisotropy, that compensates for spurious anisotropies induced by local detector effects. We find no evidence for a large-scale dipole anisotropy in the data, consistent with official results based on the conventional East-West derivative method. On the other hand, a subset of cosmic rays with median energy of 33 PeV shows strong evidence for a medium-scale feature with an angular diameter of 40 degrees. After accounting for the look-elsewhere effect, the post-trial significance of this medium-scale feature is at the level of 4$\sigma$.

    ↳ astro-ph.HEhep-exhep-phApJL(2019)·10 citations
19. 19*

    Light Nuclei Production in Au+Au Collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5-200 GeV from JAM model

    Hui Liu🇨🇳 · Dingwei Zhang🇨🇳 · Shu He🇨🇳 · Kai-jia Sun🇺🇸 · Ning Yu🇨🇳 · Xiaofeng Luo🇨🇳

    Light nuclei production is sensitive to the baryon density fluctuations and can be used to probe the QCD phase transition in relativistic heavy-ion collisions. In this work, we studied the production of proton, deuteron, triton in central Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5, 7.7, 11.5, 14.5, 19.6, 27, 39, 54.4, 62.4 and 200 GeV from a transport model (JAM). Based on the coalescence production of light nuclei, we calculated the energy dependence of rapidity density $dN/dy$ and particle ratios ($d/p$, $t/p$, and $t/d$). More importantly, the yield ratio $N_t\times N_p/N_d^2$, which is sensitive to the neutron density fluctuations, shows a flat energy dependence and cannot describe the non-monotonic trend observed by the STAR experiment. Based on the nucleon coalescence, this work can provide constraint and reference to search for the QCD critical point and/or first order phase transition with light nuclei production in future heavy-ion collision experiments.

    ↳ nucl-thhep-phnucl-exPLB(2020)·57 citations
20. 20*

    Finite-density QCD transition in magnetic field background

    V.V. Braguta🇷🇺 · M.N. Chernodub🇫🇷 · A.Yu. Kotov🇷🇺 · A.V. Molochkov🇷🇺 · A.A. Nikolaev🇬🇧

    Using numerical simulations of lattice QCD with physical quark masses, we reveal the influence of magnetic-field background on chiral and deconfinement crossovers in finite-temperature QCD at low baryonic density. In the absence of thermodynamic singularity, we identify these transitions with inflection points of the approximate order parameters: normalized light-quark condensate and renormalized Polyakov loop, respectively. We show that the quadratic curvature of the chiral transition temperature in the ``temperature--chemical potential'' plane depends rather weakly on the strength of the background magnetic field. At weak magnetic fields, the thermal width of the chiral crossover gets narrower as the density of the baryon matter increases, possibly indicating a proximity to a real thermodynamic phase transition. Remarkably, the curvature of the chiral thermal width flips its sign at $e{B}_{\mathrm{fl}}\simeq 0.6{\mathrm{GeV}}^2$, so that above the flipping point $B>B_{\mathrm{fl}}$, the chiral width gets wider as the baryon density increases. Approximately at the same strength of magnetic field, the chiral and deconfining crossovers merge together at $T\approx 140\mathrm{MeV}$. The phase diagram in the parameter space ``temperature-chemical potential-magnetic field'' is outlined, and single-quark entropy and single-quark magnetization are explored. The curvature of the chiral thermal width allows us to estimate an approximate position of the chiral critical endpoint at zero magnetic field: $(T_c^{\text{CEP}},{\mu }_B^{\text{CEP}})=(100(25)\text{MeV},800(140)\text{MeV})$.

    ↳ hep-lathep-phPRD(2019)·35 citations
21. 21*

    Renormalon structure in compactified spacetime

    Kosuke Ishikawa🇯🇵 · Okuto Morikawa🇯🇵 · Kazuya Shibata🇯🇵 · Hiroshi Suzuki🇯🇵 · Hiromasa Takaura🇯🇵

    We point out that the location of renormalon singularities in theory on a circle-compactified spacetime ${\mathbb{R}}^{d-1}\times S^1$ (with a small radius $R\Lambda \ll 1$) can differ from that on the non-compactified spacetime ${\mathbb{R}}^d$. We argue this under the following assumptions, which are often realized in large $N$ theories with twisted boundary conditions: (i) a loop integrand of a renormalon diagram is volume independent, i.e. it is not modified by the compactification, and (ii) the loop momentum variable along the $S^1$ direction is not associated with the twisted boundary conditions and takes the values $n/R$ with integer $n$. We find that the Borel singularity is generally shifted by $-1/2$ in the Borel $u$-plane, where the renormalon ambiguity of $\mathcal{O}({\Lambda }^k)$ is changed to $\mathcal{O}({\Lambda }^{k-1}/R)$ due to the circle compactification ${\mathbb{R}}^d\to {\mathbb{R}}^{d-1}\times S^1$. The result is general for any dimension $d$ and is independent of details of the quantities under consideration. As an example, we study the $\mathbb{C}{P}^{N-1}$ model on $\mathbb{R}\times S^1$ with ${\mathbb{Z}}_N$ twisted boundary conditions in the large $N$ limit.

    ↳ hep-thhep-lathep-phPTEP(2020)·19 citations
22. 22*

    Quantifying multinucleon effect in Argon using high-pressure TPC

    Jaydip Singh🇮🇳 · Srishti Nagu🇮🇳 · Jyotsna Singh🇮🇳 · R.B. Singh🇮🇳

    Neutrino oscillation experiments use heavy nuclear targets to achieve sufficient interaction rates. Nuclear effects are introduced in the experimental environment by the use of these targets and need to be quantified as they add to the systematic errors. In the low energy region(around 1 GeV) multinucleon events are also present along with Quasi Elastic(QE) and Delta interactions. Therefore if these multinucleon events are not incorporated in the data set properly, we end up with an inaccurate reconstruction of neutrino energy. In our work, we have illustrated the importance of incorporation of multinucleon events for the reduction of systematic errors in physics predictions by DUNE-Near Detector(ND). To achieve this we have presented the event distribution ratio of Ar/C, Ar/Ar, and C/C as a function of squared four-momentum transfer by employing different nuclear models. This analysis recommends the addition of 2p2h or multinucleon events in the event sample and promotes model with Random Phase Approximations(RPA) effect for the analysis of the event sample to overcome or reduce the systematic uncertainties.

    ↳ nucl-thhep-phNPB(2020)·11 citations
23. 23*

    Kinetic approach to the Schwinger effect during inflation

    E.V. Gorbar🇺🇦 · A.I. Momot🇺🇦 · O.O. Sobol🇨🇭 · S.I. Vilchinskii🇨🇭

    Using the kinetic approach, we study the impact of the charged particles dynamics due to the Schwinger effect on the electric field evolution during inflation. As a simple model of the electric field generation, we consider the kinetic coupling of the electromagnetic field to the inflaton via the term $f^2(\varphi )F_{\mu \nu }{F}^{\mu \nu }$ with the Ratra coupling function $f=\exp (\beta \varphi /M_p)$. The production of charged particles is taken into account in the Boltzmann kinetic equation through the Schwinger source term. Produced particles are thermalized due to collisions which we model by using the collision integral in the self-consistent relaxation time approximation. We found that the current of created particles exhibits a non-Markovian character and cannot be described by a simple Ohm's law relation $j\propto E$. On the contrary, the electric current as well as the electric field are oscillatory functions of time with decreasing amplitudes and a phase difference due to the ballistic motion of charged carriers. Our qualitative results are checked by using a hydrodynamic approach. Deriving a closed system of equations for the number, current, and energy densities of charged particles and determining its solution, we find a good agreement with the results obtained in the kinetic approach.

    ↳ gr-qchep-phPRD(2019)·19 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.