Thu·Apr 16, 2020Thursday·April 16, 2020

1. 01*

   $J/\psi$ meson production in SIDIS: matching high and low transverse momentum

   Daniël Boer🇳🇱 · Umberto D'Alesio🇮🇹 · Francesco Murgia🇮🇹 · Cristian Pisano🇮🇹 · Pieter Taels🇫🇷

   We consider the transverse momentum spectrum and the $\cos 2\varphi$ azimuthal distribution of $J/\psi$ mesons produced in semi-inclusive, deep-inelastic electron-proton scattering, where the electron and the proton are unpolarized. At low transverse momentum, we propose factorized expressions in terms of transverse momentum dependent gluon distributions and shape functions. We show that our formulae, at the order ${\alpha }_s,$ correctly match with the collinear factorization results at high transverse momentum. The latter are computed at the order ${\alpha }_s^2$ in the framework of nonrelativistic QCD (NRQCD), with the inclusion of the intermediate ${}^3{S}_1^{[1]}$ color-singlet Fock state, as well as the subleading color-octet ones that are relatively suppressed by a factor $v^4$ in the NRQCD velocity parameter $v$. We show that the ${}^1{S}_0^{[8]}$ and ${}^3{P}_J^{[8]}$ ($J=0,1,2$) contributions diverge in the small transverse momentum region and allow us to determine the perturbative tails of the shape functions, which carry the same quantum numbers. These turn out to be identical, except for the overall magnitude given by the appropriate NRQCD long distance matrix element.

   hep-phJHEP(2020)·50 citations
2. 02*

   Coupled Boltzmann Transport Equations of Heavy Quarks and Quarkonia in Quark-Gluon Plasma

   Xiaojun Yao🇺🇸 · Weiyao Ke🇺🇸 · Yingru Xu🇺🇸 · Steffen A. Bass🇺🇸 · Berndt Müller🇺🇸

   We develop a framework of coupled transport equations for open heavy flavor and quarkonium states, in order to describe their transport inside the quark-gluon plasma. Our framework is capable of studying simultaneously both open and hidden heavy flavor observables in heavy-ion collision experiments and can account for both, uncorrelated and correlated recombination. Our recombination implementation depends on real-time open heavy quark and antiquark distributions. We carry out consistency tests to show how the interplay among open heavy flavor transport, quarkonium dissociation and recombination drives the system to equilibrium. We then apply our framework to study bottomonium production in heavy-ion collisions. We include ${\rm Y}(1S)$, ${\rm Y}(2S)$, ${\rm Y}(3S)$, ${\chi }_b(1P)$ and ${\chi }_b(2P)$ in the framework and take feed-down contributions during the hadronic gas stage into account. Cold nuclear matter effects are included by using nuclear parton distribution functions for the initial primordial heavy flavor production. A calibrated $2+1$ dimensional viscous hydrodynamics is used to describe the bulk QCD medium. We calculate both the nuclear modification factor $R_{\mathrm{AA}}$ of all bottomonia states and the azimuthal angular anisotropy coefficient $v_2$ of the ${\rm Y}(1S)$ state and find that our results agree reasonably with experimental measurements. Our calculations indicate that correlated cross-talk recombination is an important production mechanism of bottomonium in current heavy-ion experiments. The importance of correlated recombination can be tested experimentally by measuring the ratio of $R_{\mathrm{AA}}({\chi }_b(1P))$ and $R_{\mathrm{AA}}({\rm Y}(2S))$.

   hep-phnucl-thJHEP(2021)·118 citations
3. 03*

   Hydrodynamization and non-equilibrium Green's functions in kinetic theory

   Syo Kamata🇺🇸 · Mauricio Martinez🇺🇸 · Philip Plaschke🇩🇪 · Stephan Ochsenfeld🇩🇪 · S. Schlichting🇩🇪

   Non-equilibrium Green's functions provide an efficient way to describe the evolution of the energy-momentum tensor during the early time pre-equilibrium stage of high-energy heavy ion collisions. Besides their practical relevance they also provide a meaningful way to address the question when and to what extent a hydrodynamic description of the system becomes applicable. Within the kinetic theory framework we derive a new method to calculate time dependent non-equilibrium Green's functions describing the evolution of energy and momentum perturbations on top of an evolving far-from-equilibrium background. We discuss the approach towards viscous hydrodynamics along with the emergence of various scaling phenomena for conformal systems. By comparing our results obtained in the relaxation time approximation to previous calculations in Yang-Mills kinetic theory, we further address the question which macroscopic features of the energy momentum tensor are sensitive to the underlying microscopic dynamics.

   hep-phcond-mat.stat-mechhep-thnucl-thPRD(2020)·56 citations
4. 04*

   Possibility of bottom-catalyzed matter genesis near to primordial QGP hadronization

   Cheng Tao Yang🇺🇸 · Johann Rafelski🇺🇸

   We study bottom flavor abundance in the early Universe near to a temperature $T_{\mathrm{H}}\simeq 150\mathrm{MeV}$, the condition for hadronization of deconfined quark-gluon plasma (QGP). We show bottom flavor abundance nonequilibrium lasting microseconds. In our study we use that in both QGP, and the hadronic gas phase (HG) $b$ and $\bar{b}$ quarks near $T_{\mathrm{H}}$ are bound in B-mesons and antimesons subject to $CP$ violating weak decays. A coincident non-equilibrium abundance of bottom flavor can lead to matter genesis at required strength: a) The specific thermal yield per entropy is $n_b^{th}/\sigma =10^{-10}\sim 10^{-13}$. b) Considering time scales, millions of cycles of B-meson decays, and $b\bar{b}$-pair recreation processes occur.

   hep-phastro-ph.COnucl-th4 citations
5. 05*

   Energy dependence of the inelasticity in $pp/p\bar{p}$ collisions from experimental information on charged particle multiplicity distributions

   P.C. Beggio🇧🇷 · F.R. Coriolano🇧🇷

   The dependence of the inelasticity in terms of the center of mass energy is studied in the eikonal formalism, which provides connection between elastic and inelastic channels. Due to the absence of inelasticity experimental datasets, the present analysis is based on experimental information available on the full phase space multiplicity distribution covering a large range of energy, namely 30 $<$ $\sqrt{s}$ $\le$ 1800 GeV. Our results indicate that the decrease of inelasticity is consequence of minijets production from semihard interactions arising from the scattering of gluons carrying only a very small fractions of the momenta from their parent protons. Alternative methods of estimating the inelasticity are discussed and predictions to the LHC energies are presented.

   hep-phEPJC(2020)·6 citations
6. 06*

   Diffractive dijet photoproduction at the EIC

   V. Guzey🇷🇺 · M. Klasen🇩🇪

   We present a first, detailed study of diffractive dijet photoproduction at the recently approved electron-ion collider (EIC) at BNL. Apart from establishing the kinematic reaches for various beam types, energies and kinematic cuts, we make precise predictions at next-to-leading order (NLO) of QCD in the most important kinematic variables. We show that the EIC will provide new and more precise information on the diffractive parton density functions (PDFs) in the pomeron than previously obtained at HERA, illuminate the still disputed mechanism of global vs.\ only resolved-photon factorization breaking, and provide access to a completely new quantity, i.e. nuclear diffractive PDFs.

   hep-phhep-exnucl-exnucl-thJHEP(2020)·13 citations
7. 07*

   Proton Holography -- Discovering Odderon from Scaling Properties of Elastic Scattering

   T. Csorgo🇭🇺 · T. Novak🇭🇺 · R. Pasechnik🇸🇪 · A. Ster🇭🇺 · I. Szanyi🇭🇺

   We investigate the scaling properties of elastic scattering data at ISR and LHC energies and find that the significance of an Odderon observation is larger than the discovery threshold of 5$\sigma$. As an unexpected by-product of these investigations, for certain experimentally relevant cases, we also conjecture the possibility of proton holography with the help of elastic proton-proton scattering.

   hep-phhep-exnucl-exnucl-thEPJ Web Conf.(2020)·3 citations
8. 08*

   Nuclear $p_{\perp }$-broadening of Drell-Yan and quarkonium production from SPS to LHC

   François Arleo🇫🇷 · Charles-Joseph Naïm🇫🇷

   The nuclear $p_{\perp }$-broadening of Drell-Yan and quarkonium ($J/\psi$, ${\rm Y}$) production in $\pi$A and pA collisions is investigated. The world data follow a simple scaling from SPS to LHC energies, once the process-dependent color factors are properly taken into account, which allows for the extraction of the transport coefficient in cold nuclear matter. We find that $\hat{q}(x)\propto x^{-\alpha }$ with $\alpha =0.25$-$0.30$. The magnitude of the transport coefficient at $x=10^{-2}$ is ${\hat{q}}_0=0.051$ GeV${}^2$/fm and ${\hat{q}}_0=0.075$ GeV${}^2$/fm, whether $Q\bar{Q}$ pairs are assumed to be produced as color octet or color singlet states, respectively. The relation between nuclear broadening data and the (CT14) gluon density is also investigated.

   hep-phhep-exJHEP(2020)·17 citations
9. 09*

   Estimating the Color Lifetime of Energetic Quarks

   William K. Brooks🇨🇱 · Jorge A. López🇨🇱

   Using a simple geometric framework with a realistic nuclear density distribution, we fit published HERMES data to determine fundamental properties of hadronization using the nuclear medium as a spatial analyzer. Our approach uses a fit to the transverse momentum broadening observable and the hadronic multiplicity ratio; the simultaneous fit to two different observables strongly constrains the outcome. Using the known sizes of the target nuclei, we extract the color lifetime, finding a z${}_{\mathrm{h}}$-dependent range of values from 2 to 8 fm/c for these data. We also extract estimates for the $\hat{q}$ transport coefficient characterizing the strength of the interaction between the quark and the cold nuclear medium, finding an average value of 0.035$\pm$0.011 GeV${}^2$/fm. With a three-parameter model we obtain satisfactory fits to the data with a goodness-of-fit parameter ${\chi }^2$/dof of 1.1 or less. In a secondary fit of the results from that model we independently find a value for the Lund String Model string tension of 1.00$\pm$0.05 GeV/fm. We evaluated the sensitivity for extracting quark energy loss and effective in-medium hadronic cross sections using four-parameter variants of the model, finding large uncertainties in both cases. Our results suggest that hadronic interaction of forming hadrons in the nuclear medium is the primary dynamical cause of meson attenuation in the HERMES data, with quark energy loss playing a more minor role.

   hep-phhep-exnucl-exPLB(2021)·17 citations
10. 10*

    Generalized Sachs Form Factors and the Possibility of Their Measurement in Processes without and with Proton Spin Flip

    M. V. Galynskii🇧🇾 · R. E. Gerasimov🇷🇺

    The differential cross section for elastic electron proton scattering has been calculated taking into account the two photon exchange within the phenomenological description of the electromagnetic electron proton interactions. The calculation is based on the consistent evaluation of the matrix elements of the proton current in a diagonal spin basis, which makes it possible to naturally obtain expressions for the generalized Sachs form factors. A new method has been proposed to independently measure these form factors in the elastic $e\vec{p}\to e\vec{p}$ process in the case where the initial proton at rest is fully polarized along the direction of the motion of the final proton.

    hep-phJETP Lett.(2019)·6 citations
11. 11*

    Explaining B decays anomalies in SUSY models

    Dris Boubaa🇩🇿 · Shaaban Khalil🇪🇬 · Stefano Moretti🇬🇧

    Recent measurements of certain B decays indicate deviations from Standard Model (SM) predictions. We show that Supersymmetric effects can increase the Branching Ratios (BRs) of both $B\to D\tau {\nu }_{\tau }$ and $B\to D^{\ast }\tau {\nu }_{\tau }$ with respect to the SM rates, thereby approaching their newest experimentally measured values.

    hep-phJ.Phys.Conf.Ser.(2021)·4 citations
12. 12*

    Radiation reaction friction: Resistive material medium

    Martin Formanek🇺🇸 · Andrew Steinmetz🇺🇸 · Johann Rafelski🇺🇸

    We explore a novel method of describing the radiation friction of particles traveling through a mechanically resistive medium. We introduce a particle motion induced matter warping along the path in a manner assuring that charged particle dynamics occurs subject to radiative energy loss described by the Larmor formula. We compare our description with the Landau-Lifshitz-like model for the radiation friction and show that the established model exhibits non-physical behavior. Our approach predicts in the presence of large mechanical friction an upper limit on radiative energy loss being equal to the energy loss due to the mechanical medium resistance. We demonstrate that mechanical friction due to strong interactions, for example of quarks in quark-gluon plasma, can induce significant soft photon radiation.

    hep-phPRD(2020)·7 citations
13. 13*

    New limits on neutrino decay from the Glashow resonance of high-energy cosmic neutrinos

    Mauricio Bustamante (Bohr Inst. and DARK Cosmology Ctr.)🇩🇰

    Discovering neutrino decay would be strong evidence of physics beyond the Standard Model. Presently, there are only lax lower limits on the lifetime $\tau$ of neutrinos, of $\tau /m\sim 10^{-3}$ s eV${}^{-1}$ or worse, where $m$ is the unknown neutrino mass. High-energy cosmic neutrinos, with TeV-PeV energies, offer superior sensitivity to decay due to their cosmological-scale baselines. To tap into it, we employ a promising method, recently proposed, that uses the Glashow resonance ${\bar{\nu }}_e+e\to W$, triggered by ${\bar{\nu }}_e$ of 6.3 PeV, to test decay with only a handful of detected events. If most of the ${\nu }_1$ and ${\nu }_2$ decay into ${\nu }_3$ en route to Earth, no Glashow resonance would occur in neutrino telescopes, because the remaining ${\nu }_3$ have only a tiny electron-flavor content. We turn this around and use the recent first detection of a Glashow resonance candidate in IceCube to place new lower limits on the lifetimes of ${\nu }_1$ and ${\nu }_2$. For ${\nu }_2$, our limit is the current best. For ${\nu }_1$, our limit is close to the current best and, with the imminent detection of a second Glashow resonance, will vastly surpass it.

    ↳ astro-ph.HEhep-exhep-ph33 citations
14. 14*

    RES-NOVA: A new neutrino observatory based on archaeological lead

    Luca Pattavina🇮🇹 · Nahuel Ferreiro Iachellini🇩🇪 · Irene Tamborra🇩🇰

    We propose the RES-NOVA project which will hunt neutrinos from core-collapse supernovae (SN) via coherent elastic neutrino-nucleus scattering (CE$\nu$NS) using an array of archaeological lead (Pb) based cryogenic detectors. The high CE$\nu$NS cross-section on Pb and the ultra-high radiopurity of archaeological Pb enable the operation of a high statistics experiment equally sensitive to all neutrino flavors with reduced detector dimensions in comparison with existing Neutrino Observatories, and easy scalability to larger detector volumes. RES-NOVA is planned to operate according to three phases with increasing detector volumes: (60 cm)${}^3$, (140 cm)${}^3$, and ultimately 15$\times$(140 cm)${}^3$. It will be sensitive to SN bursts up to Andromeda with 5$\sigma$ sensitivity with already existing technologies and will have excellent energy resolution with $1$ keV threshold. Within our Galaxy, it will be possible to discriminate core-collapse SNe from black hole forming collapses with no ambiguity even in the first phase of RES-NOVA. The average neutrino energy of all flavors, the SN neutrino light curve, and the total energy emitted in neutrinos can potentially be constrained with a precision of few $\%$ in the final detector phase. RES-NOVA will be sensitive to flavor-blind neutrinos from the diffuse SN neutrino background with an exposure of $620$ ton $\cdot$ y. The proposed RES-NOVA project has the potential to lay down the foundations for a new generation of neutrino telescopes, while relying on a very simple technological setup

    ↳ astro-ph.HEhep-exhep-phPRD(2020)·67 citations
15. 15*

    Left-Right Entanglement Entropy for a Dp-brane with Dynamics and Background Fields

    Shirin Teymourtashlou🇮🇷 · Davoud Kamani🇮🇷

    We investigate the left-right entanglement entropy of a boundary state, corresponding to a dynamical D$p$-brane with the internal and background fields. We assume that the brane has a tangential linear motion and a rotation, and is dressed with an internal $U(1)$ gauge potential and the Kalb-Ramond tensor field $B_{\mu \nu }$. We derive the entanglement entropy via the Rényi entropy by applying the replica trick. Our calculations will be in the context of the bosonic string theory.

    ↳ hep-thhep-phEPJC(2020)·3 citations
16. 16*

    Hints of (de)confinement in Yang-Mills-Chern-Simons theories in the maximal Abelian gauge

    Luigi C. Ferreira🇧🇷 · Antonio D. Pereira🇧🇷 · Rodrigo F. Sobreiro🇧🇷

    The study of Yang-Mills theories in three dimensions is an insightful playground to grasp important features for the four-dimensional case. Additionally, in three dimensions, the Chern-Simons term can be introduced with a mass parameter of topological nature. Quantizing such a theory in the continuum demands a gauge fixing which, in general, is plagued by Gribov copies. In this work, Yang-Mills-Chern-Simons theories are quantized in the maximal Abelian gauge and the existence of infinitesimal Gribov copies is taken into account. The elimination of copies modifies the (Abelian) gluon propagator leading to two different phases: one in which all poles are complex and thus interpreted as a confining phase and another where an excitation which can be part of the physical spectrum is present.

    ↳ hep-thhep-lathep-phPRD(2020)·4 citations
17. 17*

    Model-independent energy budget of cosmological first-order phase transitions

    Felix Giese🇩🇪 · Thomas Konstandin🇩🇪 · Jorinde van de Vis🇩🇪

    We study the energy budget of a first-order cosmological phase transition, which is an important factor in the prediction of the resulting gravitational wave spectrum. Formerly, this analysis was based mostly on simplified models as for example the bag equation of state. Here, we present a model-independent approach that is exact up to the temperature dependence of the speed of sound in the broken phase. We find that the only relevant quantities that enter in the hydrodynamic analysis are the speed of sound in the broken phase and a linear combination of the energy and pressure differences between the two phases which we call pseudotrace (normalized to the enthalpy in the broken phase). The pseudotrace quantifies the strength of the phase transition and yields the conventional trace of the energy-momentum tensor for a relativistic plasma (with speed of sound squared of one third). We study this approach in several realistic models of the phase transition and also provide a code snippet that can be used to determine the efficiency coefficient for a given phase transition strength and speed of sound. It turns out that our approach is accurate to the percent level for moderately strong phase transitions, while former approaches give at best the right order of magnitude.

    ↳ astro-ph.COhep-phJCAP(2020)·182 citations
18. 18*

    Production of light nuclei at colliders -- coalescence vs. thermal model

    Stanislaw Mrowczynski🇵🇱

    The production of light nuclei in relativistic heavy-ion collisions is well described by both the thermal model, where light nuclei are in equilibrium with hadrons of all species present in a fireball, and by the coalescence model, where light nuclei are formed due to final-state interactions after the fireball decays. We present and critically discuss the two models and further on we consider two proposals to falsify one of the models. The first proposal is to measure a yield of exotic nuclide ${}^4\mathrm{Li}$ and compare it to that of ${}^4\mathrm{He}$. The ratio of yields of the nuclides is quite different in the thermal and coalescence models. The second proposal is to measure a hadron-deuteron correlation function which carries information whether a deuteron is emitted from a fireball together with all other hadrons, as assumed in the thermal model, or a deuteron is formed only after nucleons are emitted, as in the coalescence model. The $p-{}^3\mathrm{He}$ correlation function is of interest in context of both proposals: it is needed to obtain the yield of ${}^4\mathrm{Li}$ which decays into $p$ and ${}^3\mathrm{He}$, but the correlation function can also tell us about an origin of ${}^3\mathrm{He}$.

    ↳ nucl-thhep-phEur.Phys.J.ST(2020)·43 citations
19. 19*

    Towards a reliable lower bound on the location of the critical endpoint

    Matteo Giordano🇭🇺 · Konel Kapas🇭🇺 · Sandor D. Katz🇭🇺 · Daniel Nogradi🇭🇺 · Attila Pasztor🇭🇺

    We perform the first direct determination of the position of the leading singularity of the pressure in the complex chemical potential ${\mu }_B$ plane in lattice QCD using numerical simulations with 2-stout improved rooted staggered fermions. This provides a direct determination of the radius of convergence of the Taylor expansion of the pressure that does not rely on a finite-order truncation of the expansion. The analyticity issues in the complex ${\mu }_B$ plane of the grand canonical partition function of QCD with rooted staggered fermions are solved with a careful redefinition of the fermion determinant that makes it a polynomial in the fugacity on any finite lattice, without changing the continuum limit of the observables. By performing a finite volume scaling study at a single coarse lattice spacing, we show that the limiting singularity is not on the real line in the thermodynamic limit, thus showing that the radius of convergence of the Taylor expansion gives a lower bound on the location of a possible phase transition. In the vicinity of the crossover temperature at zero chemical potential, the radius of convergence turns out to be ${\mu }_B/T\approx 2$ and roughly temperature independent.

    ↳ hep-lathep-phnucl-thNPA(2021)·5 citations
20. 20*

    Finite temperature QCD with $N_f=2+1+1$ Wilson twisted mass fermions at physical pion, strange and charm masses

    Andrey Yu. Kotov🇷🇺 · Maria Paola Lombardo🇮🇹 · Anton M. Trunin🇷🇺

    We discuss recent progress in studying Quantum Chromodynamics at finite temperature using $N_f=2+1+1$ Wilson twisted mass fermions. Particular interest is in QCD symmetries and their breaking and restoration. First, we discuss the behaviour of the ${\eta }^{\prime }$ meson at finite temperature, which is tightly connected to the axial and chiral symmetries. The results suggest a small decrease of the ${\eta }^{\prime }$ mass in the pseudo-critical region coming close to the non-anomalous contribution and subsequent growth at large temperatures. Second, we present the first results of lattice simulations of Quantum Chromodynamics with $N_f=2+1+1$ twisted mass Wilson fermions at physical pion, strange and charm masses. We estimate the chiral pseudo-critical temperatures for different observables. Our preliminary results are consistent with a second order transition in the chiral limit, however other scenarios are not excluded.

    ↳ hep-lathep-phhep-thEPJA(2020)·12 citations
21. 21*

    How well do we know the neutron-matter equation of state at the densities inside neutron stars? A Bayesian approach with correlated uncertainties

    C. Drischler🇺🇸 · R. J. Furnstahl🇺🇸 · J. A. Melendez🇺🇸 · D. R. Phillips🇺🇸

    We introduce a new framework for quantifying correlated uncertainties of the infinite-matter equation of state derived from chiral effective field theory ($\chi$EFT). Bayesian machine learning via Gaussian processes with physics-based hyperparameters allows us to efficiently quantify and propagate theoretical uncertainties of the equation of state, such as $\chi$EFT truncation errors, to derived quantities. We apply this framework to state-of-the-art many-body perturbation theory calculations with nucleon-nucleon and three-nucleon interactions up to fourth order in the $\chi$EFT expansion. This produces the first statistically robust uncertainty estimates for key quantities of neutron stars. We give results up to twice nuclear saturation density for the energy per particle, pressure, and speed of sound of neutron matter, as well as for the nuclear symmetry energy and its derivative. At nuclear saturation density the predicted symmetry energy and its slope are consistent with experimental constraints.

    ↳ nucl-thastro-ph.HEhep-phnucl-exPRL(2020)·349 citations
22. 22*

    Emergence of classical structures from the quantum vacuum

    Mainak Mukhopadhyay🇺🇸 · Tanmay Vachaspati🇺🇸 · George Zahariade🇺🇸

    After a quantum phase transition the quantum vacuum can break up to form classical topological defects. We examine this process for scalar field models with $Z_2$ symmetry for different quench rates for the phase transition. We find that the number density of kinks at late times universally scales as $C{m}^{1/2}{t}^{-1/2}$ where $m$ is a mass scale in the model and $C\approx 0.22$; it does not depend on the quench timescale in contrast to the Kibble-Zurek scaling for thermal phase transitions. A subleading correction $\propto t^{-3/2}$ to the kink density depends on the details of the phase transition.

    ↳ hep-thcond-mat.otherhep-phquant-phPRD(2020)·6 citations
23. 23*

    Entropic destruction of heavy quarkonium in heavy quark cloud

    Zi-qiang Zhang🇨🇳

    Previous research has shown that the peak of the quarkonium entropy at the deconfinement transition would be related to the entropic force which induces the melting of quarkonium. In this article, we study the effect of backreaction on the entropic force in a strongly coupled plasma of adjoint matter. The backreaction covered here comes from the presence of static heavy quarks evenly distributed over such a plasma. It is found that the inclusion of backreaction increases the entropic force thus enhancing the quarkonium dissociation, in accord with the findings of the imaginary potential.

    ↳ hep-thhep-phPRD(2020)·9 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.