Fri·Oct 2, 2015Friday·October 2, 2015

1. 01*

   Low Energy Effective Theory of QCD at High Isospin Chemical Potential

   Thomas D. Cohen🇺🇸 · Srimoyee Sen🇺🇸

   The goal of this paper is to arrive at a low energy effective theory of QCD with two massless flavors of quarks at very high isospin density and zero baryon density. In a seminal paper by Son and Stephanov in the year 2001, it was conjectured that the low energy dynamics of QCD with two light flavors at asymptotically high isospin density was described by that of a pure Yang-Mills effective Lagrangian. Since the existence of a first order deconfinement phase transition with increasing temperature is a feature of every pure SU(N) Yang-Mills theory with N greater than or equal to 3, the regime considered in this paper is also expected to exhibit a first order deconfinement phase transition with increasing temperature. However, the low energy constants(LEC) of this pure Yang-Mills theory have not been calculated till date. We calculate the LEC s for this effective theory which in turn enables us to calculate the critical temperature of the deconfinement transition as a function of the isospin chemical potential ${\mu }_I$.The scaling of the critical temperature as a function of the isospin chemical potential that we find in this paper can be compared with future lattice calculations at finite isospin density.

   hep-phnucl-th1 citation
2. 02*

   True muonium: the atom that has it all

   Henry Lamm🇺🇸

   Fundamental physics could be described as having a muon problem. Discrepancies between theory and experiment in a number of muonic measurements ($r_P$, $a_{\mu }$, $H\to \mu \tau$, ${\mathcal{R}}_K$, ${\mathcal{R}}_{D^{\ast }}$) have been observed in the last decade that demand explanation. True muonium, the bound state of a muon and its antiparticle, has the potential to put strong constraints on any beyond standard model physics that affects the muon sector. To study these effects, theoretical predictions and experiment need a, not unreasonable, precision of 100 MHz. Surprisingly, at this level, QCD and electroweak corrections become relevant in true muonium as well. Presented here is a discussion of the novel properties of true muonium from the standard model, potential discovery methods at near future facilities like DIRAC and HPS, and its ability to discriminate between a variety of solutions to the muon problem.

   hep-ph12 citations
3. 03*

   Intrinsic charm in a matched general-mass scheme

   Richard D. Ball🇬🇧 · Valerio Bertone🇬🇧 · Marco Bonvini🇬🇧 · Stefano Forte🇮🇹 · Patrick Groth Merrild🇬🇧 · Juan Rojo🇬🇧 · Luca Rottoli🇬🇧

   The FONLL general-mass variable-flavour number scheme provides a framework for the matching of a calculation in which a heavy quark is treated as a massless parton to one in which the mass dependence is retained throughout. We describe how the usual formulation of FONLL can be extended in such a way that the heavy quark parton distribution functions are freely parameterized at some initial scale, rather than being generated entirely perturbatively. We specifically consider the case of deep-inelastic scattering, in view of applications to PDF determination, and the possible impact of a fitted charm quark distribution on $F_2^c$ is assessed.

   hep-phPLB(2016)·68 citations
4. 04*

   Naturally Large Radiative Lepton Flavor Violating Higgs Decay Mediated by Lepton-flavored Dark Matter

   Seungwon Baek🇰🇷 · Zhaofeng Kang🇰🇷

   In the standard model (SM), lepton flavor violating (LFV) Higgs decay is absent at renormalizable level and thus it is a good probe to new physics. In this article we study a type of new physics that could lead to large LFV Higgs decay, i.e., a lepton-flavored dark matter (DM) model which is specified by a Majorana DM and scalar lepton mediators. Different from other similar models with similar setup, we introduce both left-handed and right-handed scalar leptons. They allow large LFV Higgs decay and thus may explain the tentative Br$(h\text{ra}\tau \mu )\sim 1\%$ experimental results from the LHC. In particular, we find that the stringent bound from $\tau \text{ra}\mu \gamma$ can be naturally evaded. One reason, among others, is a large chirality violation in the mediator sector. Aspects of relic density and especially radiative direct detection of the leptonic DM are also investigated, stressing the difference from previous lepton-flavored DM models.

   hep-phastro-ph.COhep-exJHEP(2016)·62 citations
5. 05*

   Kaon Theory News

   Andrzej J. Buras🇩🇪

   During the last fifteen years B_{s,d} decays, B_{s,d}^0-\bar B^0_{s,d} mixings, CP-violating asymmetries S_{\psi K_S} and S_{\psi\phi} provided the dominant information about the pattern of flavour violation within the SM and its extensions. We emphasize that in the coming years K meson physics will certainly strike back through the measurements of the branching ratios of theoretically very clean decays K^+->pi^+\nu\bar\nu and K_L->\pi^0\nu\bar\nu and improved calculations of the ratio epsilon'/epsilon=\epe. We summarize the status of K^+->pi^+\nu\bar\nu and K_L->\pi^0\nu\bar\nu within the SM and simplified NP models and update the picture of flavour violation in the Littlest Higgs model with T-parity taking all available constraints into account. But the highlight of this talk are new results on \epe from lattice QCD and large N approach that give a strong indication for a new anomaly in flavour physics, this time coming from K mesons. Indeed, \epe within the SM is found to be significantly below the data of NA48 and KTeV collaborations. Combining lattice results on the non-perturbative parameters B6 and B8 with the assumption that the SM dynamics dominates the Delta I=1/2 rule a 3 sigma anomaly in \epe emerges. Moreover, the recently derived upper bounds on B6 and B8 from large N approach increase the confidence that the found anomaly could be an important signal of NP at work. Of particular importance are the correlations between K^+->pi^+\nu\bar\nu, K_L->\pi^0\nu\bar\nu and \epe. With future precise measurements of K^+->pi^+\nu\bar\nu and K_L->\pi^0\nu\bar\nu and improved calculations of \epe they will surely provide powerful tools for selecting the favourite NP models. We illustrate this with the help of the LHT model and simplified models in which NP in K\to\pi\nu\bar\nu and \epe is governed by Z with flavour violating couplings or by a heavy Z'.

   hep-phhep-exhep-latPoS(2015)·11 citations
6. 06*

   Nucleon structure functions at small $x$ via holographic Pomeron exchange

   Akira Watanabe🇹🇼 · Katsuhiko Suzuki🇯🇵

   The analysis on nucleon structure functions at small Bjorken $x$ in the framework of holographic QCD is presented. In the model setup, the complicated nonperturbative interaction between the virtual photon and the target nucleon is described via the Pomeron exchange, which corresponds to the reggeized graviton exchange in the AdS space. We show that our calculations for both $F_2$ and $F_L$ structure functions are in agreement with the experimental data measured at HERA.

   hep-phnucl-thJPS Conf.Proc.(2016)·2 citations
7. 07*

   Dark Matter Searches for Monoenergetic Neutrinos Arising from Stopped Meson Decay in the Sun

   Carsten Rott🇰🇷 · Seongjin In🇰🇷 · Jason Kumar🇺🇸 · David Yaylali🇺🇸

   Dark matter can be gravitationally captured by the Sun after scattering off solar nuclei. Annihilations of the dark matter trapped and accumulated in the centre of the Sun could result in one of the most detectable and recognizable signals for dark matter. Searches for high-energy neutrinos produced in the decay of annihilation products have yielded extremely competitive constraints on the spin-dependent scattering cross sections of dark matter with nuclei. Recently, the low energy neutrino signal arising from dark-matter annihilation to quarks which then hadronize and shower has been suggested as a competitive and complementary search strategy. These high-multiplicity hadronic showers give rise to a large amount of pions which will come to rest in the Sun and decay, leading to a unique sub-GeV neutrino signal. We here improve on previous works by considering the monoenergetic neutrino signal arising from both pion and kaon decay. We consider searches at liquid scintillation, liquid argon, and water Cherenkov detectors and find very competitive sensitivities for few-GeV dark matter masses.

   hep-phastro-ph.HEJCAP(2015)·38 citations
8. 08*

   Production of charged Higgs boson pairs in the $pp\to pp{H}^{+}{H}^{-}$ reaction at the LHC and FCC

   Piotr Lebiedowicz🇵🇱 · Antoni Szczurek🇵🇱

   We present differential cross sections for the $pp\to pp{H}^{+}{H}^{-}$ reaction via photon-photon fusion with exact kinematics. We show predictions for $\sqrt{s}$ = 14 TeV (LHC) and at the Future Circular Collider (FCC) for $\sqrt{s}$ = 100 TeV. The integrated cross section for $\sqrt{s}$ = 14~TeV (LHC) is about 0.1~fb and about 0.9~fb at the FCC for $\sqrt{s}$ = 100~TeV when assuming $m_{H^{\pm }}=150$~GeV. We present distributions in diHiggs boson invariant mass. The results are compared with those obtained within equivalent-photon approximation. We discuss also first calculations of cross section for exclusive diffractive pQCD mechanism with estimated limits on the $g_{h{H}^{+}{H}^{-}}$ coupling constant within 2HDM based on the LHC experimental data. The diffractive contribution is much smaller than the $\gamma \gamma$ one. Absorption corrections are calculated differentially for various distributions. In general, they lead to a damping of the cross section. The damping depends on $M_{H^{+}{H}^{-}}$ invariant mass and on four-momentum transfers squared in the proton line. We discuss a possibility to measure the exclusive production of $H^{\pm }$ bosons.

   hep-phPoS(2015)·0 citations
9. 09*

   Numerical implementation of the Loop-Tree Duality method

   Sebastian Buchta🇪🇸 · Grigorios Chachamis🇪🇸 · Petros Draggiotis🇬🇷 · German Rodrigo🇪🇸

   We present a first numerical implementation of the Loop-Tree Duality (LTD) method for the direct numerical computation of multi-leg one-loop Feynman integrals. We discuss in detail the singular structure of the dual integrands and define a suitable contour deformation in the loop three-momentum space to carry out the numerical integration. Then, we apply the LTD method to the computation of ultraviolet and infrared finite integrals, and present explicit results for scalar integrals with up to five external legs (pentagons) and tensor integrals with up to six legs (hexagons). The LTD method features an excellent performance independently of the number of external legs.

   hep-phEPJC(2017)·105 citations
10. 10*

    Measuring CP-Violating Observables in Rare Top Decays at the LHC

    Pratishruti Saha🇨🇦 · Ken Kiers🇺🇸 · Bhubanjyoti Bhattacharya🇨🇦 · David London🇨🇦 · Alejandro Szynkman🇦🇷 · Jordan Melendez🇺🇸

    In this paper we consider CP-violating new-physics contributions to the decay $t\to b\bar{b}c$. We examine the prospects for detecting such new physics at the LHC, which requires studying the process $gg\to t(\to b\bar{b}c)\bar{t}(\to \bar{b}\ell \bar{\nu })$. We find two observables that can be used to reveal the presence of CP-violating new physics in $t\to b\bar{b}c$. They are (i) the partial-rate asymmetry and (ii) the triple-product correlations involving the momenta of various particles associated with the interaction. A Monte Carlo analysis is performed to determine how well these observables can be used to detect the presence of new physics, and to measure its parameters. We find that there is little difficulty in extracting the value of the relevant new-physics parameter from the partial-rate asymmetry. For the triple-product correlations, we test multiple strategies that can be used for the extraction of the corresponding combination of new-physics parameters.

    hep-phhep-exPRD(2016)·5 citations
11. 11*

    Light dark matter candidates in intense laser pulses II: the relevance of the spin degrees of freedom

    Selym Villalba-Chávez🇩🇪 · Carsten Müller🇩🇪

    Optical searches assisted by the field of a laser pulse might allow for exploring a variety of not yet detected dark matter candidates such as hidden-photons and scalar minicharged particles. These hypothetical degrees of freedom may be understood as a natural consequence of extensions of the Standard Model incorporating a hidden $\mathrm{U}(1)$-gauge sector. In this paper, we study the effects induced by both candidates on the propagation of a probe electromagnetic waves in the vacuum polarized by a long laser pulse of moderate intensity, this way complementing our previous study [JHEP \textbf{06}, $177$ ($2015$)]. We describe how the absence of a spin in the scalar charged carriers modifies the photon-paraphoton oscillations as compared with a fermionic minicharge model. In particular, we find that the regime close to their lowest threshold mass might provide the most stringent upper limit for minicharged scalars. The pure-laser based experiment investigated here could allow 23for excluding a sector in the parameter space of the particles which has not been experimentally ruled out by setups driven by dipole magnets. We explain how the sign of the ellipticity and rotation of the polarization plane acquired by a probe photon--in combination with their dependencies on the pulse parameters--can be exploited to elucidate the quantum statistics of the charge carriers.

    hep-phJHEP(2016)·10 citations
12. 12*

    Exotic see-saw mechanism for neutrinos and leptogenesis in a Pati-Salam model

    Andrea Addazi🇮🇹 · Massimo Bianchi🇮🇹 · Giulia Ricciardi🇮🇹

    We discuss non-perturbative corrections to the neutrino sector, in the context of a D-brane Pati-Salam-like model, that can be obtained as a simple alternative to $SO(10)$ GUT's in theories with open and unoriented strings. In such D-brane models, exotic stringy instantons can correct the right-handed neutrino mass matrix in a calculable way, thus affecting mass hierarchies and modifying the see-saw mechanism to what we name exotic see-saw. For a wide range of parameters, a compact spectrum of right-handed neutrino masses can occur that gives rise to a predictive scenario for low energy observables. This model also provides a viable mechanism for Baryon Asymmetry in the Universe (BAU) through leptogenesis. Finally, a Majorana mass for the neutron is naturally predicted in the model, leading to potentially testable neutron-antineutron oscillations. Combined measurements in neutrino and neutron-antineutron sectors could provide precious informations on physics at the quantum gravity scale.

    hep-phJHEP(2016)·34 citations
13. 13*

    Status and prospects of the nMSSM after LHC Run-1

    D. Barducci🇫🇷 · G. Bélanger🇫🇷 · C. Hugonie🇫🇷 · A. Pukhov🇷🇺

    The new minimal supersymmetric standard model (nMSSM), a variant of the general next to minimal supersymmetric standard model (NMSSM) without $Z_3$ symmetry, features a naturally light singlino with a mass below 75 GeV. In light of the new constraints from LHC Run-1 on the Higgs couplings, sparticles searches and flavour observables, we define the parameter space of the model which is compatible with both collider and dark matter (DM) properties. Among the regions compatible with these constraints, implemented through NMSSMTools, SModelS and MadAnalysis 5, only one with a singlino lightest supersymmetric particle (LSP) with a mass around 5 GeV can explain all the DM abundance of the universe, while heavier mixed singlinos can only form one of the DM components. Typical collider signatures for each region of the parameter space are investigated. In particular, the decay of the 125 GeV Higgs into light scalars and/or pseudoscalars and the decay of the heavy Higgs into charginos and neutralinos, provide distinctive signatures of the model. Moreover, the sfermion decays usually proceed through heavier neutralinos rather than directly into the LSP, as the couplings to the singlino are suppressed. We also show that direct detection searches are complementary to collider ones, and that a future ton-scale detector could completely probe the region of parameter space with a LSP mass around 65 GeV.

    hep-phJHEP(2016)·23 citations
14. 14*

    Two-photon dilepton production in proton-proton collisions: two alternative approaches

    Marta Luszczak🇵🇱 · Wolfgang Schafer🇵🇱 · Antoni Szczurek🇵🇱

    We investigate different methods to incorporate the effect of photons in hard processes. We compare two different approaches used for calculating cross sections for two-photon $pp\to l^{+}{l}^{-}X$ process. In one of the approaches photon is treated as a collinear parton in the proton. In the second approach recently proposed a $k_T$-factorization method is used. We discuss how results of the collinear parton model depend on the initial condition for the QCD evolution and discuss an approximate treatment where photon is excluded from the combined QCD-QED evolution. We demonstrate that it is not necessary to put photon into the evolution equation as often done recently but it is sufficient to use a simplified approach in which photon couples to quarks and antiquarks which by themselves undergo DGLAP evolution equations. We discuss sensitivity of the results to the choice of structure function parametrization and experimental cuts in the $k_T$-factorization approach. A new optimal structure function parametrization is proposed. We compare results of our calculations with recent experimental data for dilepton production and find that in most cases the contribution of the photon-photon mechanism is rather small. We discuss how to enhance the photon-photon contribution. We also compare our results to those of recent measurements of exclusive and semi-exclusive $e^{+}{e}^{-}$ pair production with certain experimental data by the CMS collaboration.

    hep-phPRD(2016)·48 citations
15. 15*

    The simplest 3-3-1 model

    Le Tho Hue🇻🇳 · Le Duc Ninh🇩🇪

    A simple extension of the Standard Model (SM), based on the gauge group $SU(3{)}_C\otimes SU(3{)}_L\otimes U(1{)}_Y$ with $Y$ being the hypercharge, is considered. We show that, by imposing an approximate global $SU(2{)}_L\times SU(2{)}_R$ custodial symmetry at the SM energy scale, the $Z-Z^{\prime }$ mixing is absent at tree level and the value of the $\rho$ parameter can be kept close to one. Tree-level flavor-changing neutral currents are also reduced to three particles, namely $Z^{\prime }$, a CP-odd Higgs and a CP-even Higgs. The model predicts new leptons with electric charges of $\pm 1/2e$ and new quarks with $\pm 1/6e$ charges as well as new gauge and scalar bosons with $\pm 1/2e$ charges. Electric charge conservation requires that one of them must be stable. Their masses are unfortunately free parameters.

    hep-phhep-exMod.Phys.Lett.A(2016)·27 citations
16. 16*

    Flavor & new physics opportunities with rare charm decays into leptons

    Stefan de Boer🇩🇪 · Gudrun Hiller🇩🇪

    Updated standard model predictions for $D_{(s)}\to P{l}^{+}{l}^{-}$, $l=e,\mu$, $P=\pi ,K$ and inclusive decays are presented. Model-independent constraints on $|\Delta C|=|\Delta U|=1$ Wilson coefficients are worked out. New physics (NP) opportunities arise in semileptonic branching ratios for very large couplings only, however, are not excluded outside the resonance regions yet. The NP potential of resonance-assisted CP asymmetries and angular observables is worked out. Predictions are given for leptoquark models, and include lepton flavor violating and dineutrino decays. Whether NP can be seen depends on flavor patterns, and vice versa.

    hep-phPRD(2016)·126 citations
17. 17*

    Chemical freeze-out in Hawking-Unruh radiation and quark-hadron transition

    Abdel Nasser Tawfik (Egyptian Ctr. Theor. Phys., Cairo, WLCAPP, Cairo)🇪🇬 · Hayam Yassin🇪🇬 · Eman R. Abo Elyazeed (Ain Shams U., Cairo)🇪🇬

    The proposed analogy between hadron production in high-energy collisions and Hawking-Unruh radiation process in the black holes shall be extended. This mechanism provides a theoretical basis for the freeze-out parameters, the temperature ($T$) and the baryon chemical potential ($\mu$), characterizing the final state of particle production. The results from charged black holes, in which the electric charge is related to $\mu$, are found comparable with the phenomenologically deduced parameters from the ratios of various particle species and the higher-order moments of net-proton multiplicity in thermal statistical models and Polyakov linear-sigma model. Furthermore, the resulting freeze-out condition $⟨E⟩/⟨N⟩\simeq 1$GeV for average energy per particle is in good agreement with the hadronization process in the high-energy experiments. For the entropy density ($s$), the freeze-out condition $s/T^3\simeq 7$ remains valid for $\mu \lesssim 0.3$GeV. Then, due to the dependence of $T$ on $\mu$, the values of $s/T^3$ increase with increasing $\mu$. In accordance with this observation, we found that the entropy density remains constant with increasing $\mu$. Thus, we conclude that almost no information is going lost through Hawking-Unruh radiation from charged black holes. It is worthwhile to highlight that the freeze-out temperature from charged black holes is determined independent on both freeze-out conditions

    hep-phgr-qchep-thPRD(2015)·12 citations
18. 18*

    Search for extended gamma-ray emission from the Virgo galaxy cluster with Fermi-LAT

    M. Ackermann🇩🇪 · M. Ajello🇺🇸 · A. Albert🇺🇸 · W. B. Atwood🇺🇸 · L. Baldini🇮🇹 · G. Barbiellini🇮🇹 · D. Bastieri🇮🇹 · K. Bechtol🇺🇸 · R. Bellazzini🇮🇹 · E. Bissaldi🇮🇹 · E. D. Bloom🇺🇸 · R. Bonino🇮🇹 and 109 other authors

    Galaxy clusters are one of the prime sites to search for dark matter (DM) annihilation signals. Depending on the substructure of the DM halo of a galaxy cluster and the cross sections for DM annihilation channels, these signals might be detectable by the latest generation of $\gamma$-ray telescopes. Here we use three years of Fermi Large Area Telescope (LAT) data, which are the most suitable for searching for very extended emission in the vicinity of nearby Virgo galaxy cluster. Our analysis reveals statistically significant extended emission which can be well characterized by a uniformly emitting disk profile with a radius of 3\deg that moreover is offset from the cluster center. We demonstrate that the significance of this extended emission strongly depends on the adopted interstellar emission model (IEM) and is most likely an artifact of our incomplete description of the IEM in this region. We also search for and find new point source candidates in the region. We then derive conservative upper limits on the velocity-averaged DM pair annihilation cross section from Virgo. We take into account the potential $\gamma$-ray flux enhancement due to DM sub-halos and its complex morphology as a merging cluster. For DM annihilating into $b\overline{b}$, assuming a conservative sub-halo model setup, we find limits that are between 1 and 1.5 orders of magnitude above the expectation from the thermal cross section for $m_{\mathrm{DM}}\lesssim 100\mathrm{GeV}$. In a more optimistic scenario, we exclude $⟨\sigma v⟩\sim 3\times 10^{-26}\mathrm{c}{\mathrm{m}}^3{\mathrm{s}}^{-1}$ for $m_{\mathrm{DM}}\lesssim 40\mathrm{GeV}$ for the same channel. Finally, we derive upper limits on the $\gamma$-ray-flux produced by hadronic cosmic-ray interactions in the inter cluster medium. We find that the volume-averaged cosmic-ray-to-thermal pressure ratio is less than $\sim 6\%$.

    ↳ astro-ph.HEhep-phApJ(2015)·102 citations
19. 19*

    Blazar origin of some IceCube events

    Luis Salvador Miranda🇲🇽 · Alberto Rosales de León🇲🇽 · Sarira Sahu🇲🇽

    Recently ANTARES collaboration presented a time dependent analysis to a selected number of flaring blazars to look for upward going muon events produced from the charge current interaction of the muon neutrinos. We use the same list of flaring blazars to look for possible positional correlation with the IceCube neutrino events. In the context of photohadronic model we propose that the neutrinos are produced within the nuclear region of the blazar where Fermi accelerated high energy protons interact with the background synchrotron/SSC photons. Although we found that some objects from the ANTARES list are within the error circles of few IceCube events, the statistical analysis shows that none of these sources have a significant correlation.

    ↳ astro-ph.HEhep-phEPJC(2016)·5 citations
20. 20*

    Short range inter-vortex interaction and interacting dynamics of half-quantized vortices in two-component Bose-Einstein condensates

    Kenichi Kasamatsu🇯🇵 · Minoru Eto🇯🇵 · Muneto Nitta🇯🇵

    We study the interaction and dynamics of two half-quantized vortices in two-component Bose- Einstein condensates. Using the Pade approximation for the vortex core profile, we calculate the intervortex potential, whose asymptotic form for a large distance has been derived by Eto et al. [Phys. Rev. A, 83, 063603 (2011)]. Through numerical simulations of the two-dimensional Gross-Pitaevskii equations, we reveal different kinds of dynamical trajectories of the vortices depending on the combinations of signs of circulations and the intercomponent density coupling. Under the adiabatic limit, we derive the equations of motion for the vortex coordinates, in which the motion is caused by the balance between Magnus force and the intervortex forces. The initial velocity of the vortex motion can be explained quantitatively by this point vortex approximation, but under- standing the long-time behavior of the dynamics needs more consideration beyond our model.

    ↳ cond-mat.quant-gashep-phPRA(2016)·23 citations
21. 21*

    Transport coefficients and quark-hadron phase transition(s) from PLSM in vanishing and finite magnetic field

    Abdel Nasser Tawfik (Egyptian Ctr. Theor. Phys., Cairo, WLCAPP, Cairo)🇪🇬

    In peripheral heavy-ion collisions, localized ,short-lived an extremely huge magnetic field can be generated. Its possible influences on the quark-hadron phase transition(s) and the transport properties of the hadronic and partonic matter shall be analysed from the Polyakov linear-sigma model. Our calculations are compared with recent lattice QCD calculations.

    ↳ nucl-thhep-lathep-phJ.Phys.Conf.Ser.(2016)·13 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.