HEP Phenomenology·hep-ph

Mon·Jan 11, 2016Monday·January 11, 2016

26 papers—15 primary·11 cross-listed·reconstructed*

01*
Hearing the echoes of electroweak baryogenesis with gravitational wave detectors
Fa Peng Huang🇨🇳 · Youping Wan🇨🇳 · Dong-Gang Wang🇨🇳 · Yi-Fu Cai🇨🇳 · Xinmin Zhang🇨🇳
We report on the first joint analysis of observational signatures from the electroweak baryogenesis in both gravitational wave (GW) detectors and particle colliders. With an effective extension of the Higgs sector in terms of the dimension-6 operators, we derive a strong first-order phase transition in associated with a sizable CP violation to realize a successful electroweak baryogenesis. We calculate the GW spectrum resulting from the bubble nucleation, plasma transportation, and magnetohydrodynamic turbulence of this process that occurred after the big bang, and find that it yields GW signals testable in Evolved Laser Interferometer Space Antenna, Deci-hertz Interferometer Gravitational wave Observatory and Big Bang Observer. We further identify collider signals from the same mechanism that are observable at the planning Circular Electron Positron Collider. Our analysis bridges astrophysics/cosmology with particle physics by providing significant motivation for searches for GW event peaking at the $(1 0^{- 4}, 1)$ Hz range, which are associated with signals at colliders, and highlights the possibility of an interdisciplinary observational window into baryogenesis. The technique applied in analyzing early universe phase transitions may enlighten the study of phase transitions in applied science.
hep-phastro-ph.COgr-qchep-thPRD(2016)·113 citations
02*
Heavy Neutrinos at Future Colliders
P. S. Bhupal Dev🇩🇪 · Alejandro Ibarra🇩🇪
We discuss the current status and future prospects of heavy neutrino searches at the energy frontier, which might play an important role in vindicating the simplest seesaw paradigm as the new physics responsible for neutrino mass generation. After summarizing the current search limits and potential improvements at hadron colliders, we highlight the unparalleled sensitivities achievable in the clean environment of future lepton colliders.
hep-phhep-exFrascati Phys.Ser.(2016)·5 citations
03*
Three-loop cusp anomalous dimension and a conjecture for $n$ loops
Nikolaos Kidonakis🇺🇸
I present analytical expressions for the cusp anomalous dimension in QCD through three loops in terms of elementary functions and ordinary polylogarithms. I observe interesting relations between the results at different loops and provide a conjecture for the $n$ -loop cusp anomalous dimension in terms of the lower-loop results. I also present numerical results and simple approximate formulas for the cusp anomalous dimension relevant to top-quark production.
hep-phhep-thInt.J.Mod.Phys.A(2016)·17 citations
04*
Enabling Electroweak Baryogenesis through Dark Matter
Marek Lewicki🇵🇱 · Tanja Rindler-Daller🇺🇸 · James D. Wells🇺🇸
We study the impact on electroweak baryogenesis from a swifter cosmological expansion induced by dark matter. We detail the experimental bounds that one can place on models that realize it, and we investigate the modifications of these bounds that result from a non-standard cosmological history. The modifications can be sizeable if the expansion rate of the Universe increases by several orders of magnitude. We illustrate the impact through the example of scalar field dark matter, which can alter the cosmological history enough to enable a strong-enough first-order phase transition in the Standard Model when it is supplemented by a dimension six operator directly modifying the Higgs boson potential. We show that due to the modified cosmological history, electroweak baryogenesis can be realized, while keeping deviations of the triple Higgs coupling below HL-LHC sensitivies. The required scale of new physics to effectuate a strong-enough first order phase transition can change by as much as twenty percent as the expansion rate increases by six orders of magnitude.
hep-phastro-ph.COhep-thJHEP(2016)·27 citations
05*
Measuring the diphoton coupling of a 750 GeV resonance
Sylvain Fichet🇧🇷 · Gero von Gersdorff🇧🇷 · Christophe Royon🇺🇸
A slight excess has been observed in the first data of photon-photon events at the 13 TeV LHC, that might be interpreted has a hint of physics beyond the Standard Model. We show that a completely model-independent measurement of the photon-photon coupling of a putative 750 GeV resonance will be possible using the forward proton detectors scheduled at ATLAS and CMS.
hep-phPRL(2016)·105 citations
06*
The Joint Physics Analysis Center Website
Vincent Mathieu🇺🇸
The Joint Physics Analysis Center is a collaboration between theorists and experimentalists working in hadronic physics. In order to facilitate the exchange of information between the different actors in hadron spectroscopy, we created an interactive website. In this note, I summarize the first projects available on the website.
hep-phAIP Conf.Proc.(2016)·19 citations
07*
Gluon TMD studies at EIC
Daniël Boer🇳🇱
A high-energy Electron-Ion Collider (EIC) would offer a most promising tool to study in detail the transverse momentum distributions of gluons inside hadrons. This applies to unpolarized as well as linearly polarized gluons inside unpolarized protons, and to left-right asymmetric distributions of gluons inside transversely polarized protons, the so-called gluon Sivers effect. The inherent process dependence of these distributions can be studied by comparing to similar, but often complementary observables at LHC.
hep-phhep-exEPJ Web Conf.(2016)·5 citations
08*
Subdominant Left-Right Scalar Dark Matter as Origin of the 750 GeV Di-photon Excess at LHC
Debasish Borah🇮🇳 · Sudhanwa Patra🇮🇳 · Shibananda Sahoo🇮🇳
We study the possibility of explaining the recently reported 750 GeV di-photon excess at LHC within the framework of a left-right symmetric model. The 750 GeV neutral scalar in the model is dominantly an admixture of neutral components of scalar bidoublets with a tiny fraction of neutral scalar triplet. Incorporating $S U (2)$ septuplet scalar pairs into the model, we enhance the partial decay width of the 750 GeV neutral scalar into di-photons through charged septuplet components in loop while keeping the neutral septuplet components as subdominant dark matter candidates. The model also predicts the decay width of the 750 GeV scalar to be around 36 GeV to be either confirmed or ruled out by future LHC data. The requirement of producing the correct di-photon signal automatically keeps the septuplet dark matter abundance subdominant in agreement with bounds from direct and indirect detection experiments. We then briefly discuss different possibilities to account for the remaining dark matter component of the Universe in terms of other particle candidates whose stability arise either due to remnant discrete symmetry after spontaneous breaking of $U (1)_{B - L}$ or due to high $S U (2)$ -dimension forbidding their decay into lighter particles.
hep-phhep-exInt.J.Mod.Phys.A(2016)·53 citations
09*
On the universality of the $J = 0$ fixed pole contribution in DVCS
Dieter Müller🇭🇷 · Kirill M. Semenov-Tian-Shansky🇷🇺
S. Brodsky, F.J. Llanes-Estrada, and A. Szczepaniak formulated the $J = 0$ fixed pole universality hypothesis for (deeply) virtual Compton scattering. We show that in the Bjorken limit this hypothesis is equivalent to the validity of the inverse moment sum rule for the $D$ -term form factor. However, any supplementary $D$ -term added to a generalized parton distribution (GPD) results in an additional $J = 0$ fixed pole contribution that violates universality. Unfortunately, one can not provide any reliable theoretical argument excluding the existence of such supplementary $D$ -term. Moreover, the violation of $J = 0$ fixed pole universality was revealed in field theoretical GPD models. Therefore, $J = 0$ fixed pole universality hypothesis remains just an external assumption and probably will never be proven theoretically.
hep-phEPJ Web Conf.(2016)·1 citation
10*
Charged Higgs Pair Production in THDM Through Photon-photon Collisions at the ILC
Nasuf Sonmez🇹🇷
In this study, the charged Higgs pair production is analyzed for the minimal extension of the standard model called two-higgs-doublet model. The process $γ γ \to H^{+} H^{-}$ is calculated at the tree level for the ILC and the numerical analysis is presented for various parameters. The production rate of the charged Higgs boson pair as a function of center-of-mass (CM) energy and the differential cross section as a function of angle between photon and positive charged Higgs boson is presented. The cross section gets high at the low charged Higgs mass and low CM energies. The total integrated cross section of the process is also calculated at a $e^{+} e^{-}$ -collider by convoluting the $γ γ \to H^{+} H^{-}$ subprocess with the photon luminosity of the backscattered photons. The total integrated cross section peaks around $s = 650 GeV$ and have a value of $1.4 pb$ for $m_{H^{\pm}} = 100 GeV/c^{2}$ . Charged Higgs detection is very important sign for the new physics and the results shows the potential of the ILC for the search of the new physics signals.
hep-ph8 citations
11*
Neutralino Pair Production at the Photon-Photon Collider for the $τ ~$ -Coannihilation Scenario
Nasuf Sonmez🇹🇷
Supersymmetry (SUSY) is a theory that gives an explanation for the strong and electroweak interactions from the grand unification scale down to the weak scale. The search for supersymmetric particles still continues at full speed at the LHC without success. The main tasks at the ILC is complementing the LHC result and also search for new physics. In this study, the neutralino pair production via photon-photon collision is studied for the $t ~$ -coannihilation scenario in the context of MSSM at the ILC. In the calculation, all the possible one-loop diagrams are taken into account for the photon-photon interaction. We present the production cross section and distribution of various observables for the lightest and next-to-lightest neutralino pairs for benchmark models which are specifically presented in the light of LHC8 data analysis, employing these benchmark models for neutralino pair production could show the potential of the ILC concerning the dark matter searches in supersymmetry.
hep-phAIP Conf.Proc.(2016)·0 citations
12*
A Review of Higgs Mass Calculations in Supersymmetric Models
Patrick Draper🇺🇸 · Heidi Rzehak🇩🇪
The discovery of the Higgs boson is both a milestone achievement for the Standard Model and an exciting probe of new physics beyond the SM. One of the most important properties of the Higgs is its mass, a number that has proven to be highly constraining for models of new physics, particularly those related to the electroweak hierarchy problem. Perhaps the most extensively studied examples are supersymmetric models, which, while capable of producing a 125 GeV Higgs boson with SM-like properties, do so in non-generic parts of their parameter spaces. We review the computation of the Higgs mass in the Minimal Supersymmetric Standard Model, in particular the large radiative corrections required to lift $m_{h}$ to 125 GeV and their calculation via Feynman-diagrammatic and effective field theory techniques. This review is intended as an entry point for readers new to the field, and as a summary of the current status, including the existing analytic calculations and publicly-available computer codes.
hep-phPhys.Rept.(2016)·106 citations
13*
Systematics of radial excitations in heavy-light hadrons
R.M. Woloshyn🇨🇦 · Mark Wurtz🇨🇦
Some simple expectations for the quark mass dependence of radial excitation energies of heavy-light hadrons based on consideration of nonrelativistic quantum mechanics are discussed. Experimental and theoretical results are reviewed in light of these expectations. Some new lattice QCD results for masses of Lambda_b and Sigma_b baryons are presented.
hep-phhep-lat7 citations
14*
The gauge-invariant canonical energy-momentum tensor
Cédric Lorcé (Ecole polytechnique, CPHT)🇫🇷
The canonical energy-momentum tensor is often considered as a purely academic object because of its gauge dependence. However, it has recently been realized that canonical quantities can in fact be defined in a gauge-invariant way provided that strict locality is abandoned, the non-local aspect being dictacted in high-energy physics by the factorization theorems. Using the general techniques for the parametrization of non-local parton correlators, we provide for the first time a complete parametrization of the energy-momentum tensor (generalizing the purely local parametrizations of Ji and Bakker-Leader-Trueman used for the kinetic energy-momentum tensor) and identify explicitly the parts accessible from measurable two-parton distribution functions (TMDs and GPDs). As by-products, we confirm the absence of model-independent relations between TMDs and parton orbital angular momentum, recover in a much simpler way the Burkardt sum rule and derive three similar new sum rules expressing the conservation of transverse momentum.
hep-phEPJ Web Conf.(2016)·2 citations
15*
Mu to e gamma in the 2 Higgs Doublet Model: an exercise in EFT
Sacha Davidson🇫🇷
The 2 Higgs Doublet Model (2HDM) of type III has renormalisable Lepton Flavour-Violating couplings, and its one and two-loop ("Barr-Zee") contributions to $μ \to e γ$ are known. In the decoupling limit, where the mass scale M of the second doublet is much greater than the electroweak scale, the model can be parametrised with an Effective Field Theory(EFT) containing dimension six operators. The $1/ M^{2}$ terms of the exact calculation are reproduced in the EFT, provided that the four-fermion operator basis below the weak scale is enlarged with respect to the SU(2)-invariant Buchmuller-Wyler list. The two-loop "Barr-Zee" contributions are located in the EFT, showing that two-loop matching and running would be required to obtain the most important contributions, and that dimension eight operators can be numerically relevant.
hep-phEPJC(2016)·36 citations
16*
Running Vacuum in the Universe: current phenomenological status
Joan Sola🇪🇸
I review the excellent phenomenological status of a class of dynamical vacuum models in which the vacuum energy density, $ρ_{Λ} = ρ_{Λ} (H)$ , as a function of the Hubble rate, evolves through its interaction with dark matter and/or through the accompanying running of the gravitational coupling $G$ , including the possibility of being self-conserved with a nontrivial effective equation of state. Some of these models have been used to incorporate into a single vacuum structure the rapid stage of inflation, followed by the standard radiation and cold dark matter epochs all the way down until the dark energy era. Remarkably, the running vacuum models (RVM's) render an outstanding phenomenological description of the main cosmological data at a level that is currently challenging the concordance $Λ$ CDM model, thereby implying that present observations seem to point to a running vacuum rather than to a rigid cosmological constant $Λ$ in our Universe.
↳ gr-qcastro-ph.COhep-phhep-th24 citations
17*
Equation of state of a quark-Polyakov loop-meson mixture in the PNJL model at finite temperature
Juan M. Torres-Rincon🇫🇷 · Joerg Aichelin🇫🇷
Recent consensus on the $N_{f} = 2 + 1$ equation of state at vanishing chemical potential from different lattice-QCD groups has spoiled the previous agreement with the outcome from the mean-field Polyakov-Nambu-Jona-Lasinio model. In this letter we review the thermodynamics of the PNJL model introducing two important aspects needed to describe the pressure computed in the lattice QCD. First, we consider the thermodynamics of the model beyond the mean-field approach to include pseudoscalar and scalar mesonic-like fluctuations into the grand-canonical potential. This accounts for the hadronic pressure of the system below the critical temperature. On the other hand we also implement the back reaction of quarks into the Polyakov-loop effective potential bringing a reduction of the pressure above $T_{c}$ from the Stefan-Boltzmann limit. We get a good agreement with lattice-QCD data at low and moderate temperatures, opening the door to a straightforward extension to finite chemical potential.
↳ nucl-thhep-ph13 citations
18*
Primordial power spectra for scalar perturbations in loop quantum cosmology
Daniel Martín de Blas🇨🇱 · Javier Olmedo🇺🇸
We provide the power spectrum of small scalar perturbations propagating in an inflationary scenario within loop quantum cosmology. We consider the hybrid quantization approach applied to a Friedmann--Robertson--Walker spacetime with flat spatial sections coupled to a massive scalar field. We study the quantum dynamics of scalar perturbations on an effective background within this hybrid approach. We consider in our study adiabatic states of different orders. For them, we find that the hybrid quantization is in good agreement with the predictions of the dressed metric approach. We also propose an initial vacuum state for the perturbations, and compute the primordial and the anisotropy power spectrum in order to qualitatively compare with the current observations of Planck mission. We find that our vacuum state is in good agreement with them, showing a suppression of the power spectrum for large scale anisotropies. We compare with other choices already studied in the literature.
↳ gr-qcastro-ph.COhep-phJCAP(2016)·80 citations
19*
The Role of Nucleon Strangeness in Supernova Explosions
T. J. Hobbs🇺🇸 · Mary Alberg🇺🇸 · Gerald A. Miller🇺🇸
Recent hydrodynamical simulations of supernova (SN) evolution have highlighted the importance of a thorough control over microscopic physics responsible for such internal processes as neutrino heating. In particular, it has been suggested that modifications to the neutrino-nucleon elastic cross section can potentially play a crucial role in producing successful supernova explosions. One possible source of such corrections can be found in a nonzero value for the nucleon's strange helicity content $Δ s$ . In the present analysis, however, we show that theoretical and experimental progress over the past decade has suggested a comparatively small magnitude for $Δ s$ , such that its sole effect is not sufficient to provide the physics leading to supernova explosions.
↳ astro-ph.HEhep-phnucl-thPRC(2016)·25 citations
20*
The Gravitational Two-Loop Counterterm is Asymptotically Safe
Holger Gies🇩🇪 · Benjamin Knorr🇩🇪 · Stefan Lippoldt🇩🇪 · Frank Saueressig🇩🇪
Weinberg's asymptotic safety scenario provides an elegant mechanism to construct a quantum theory of gravity within the framework of quantum field theory based on a non-Gaußian fixed point of the renormalization group flow. In this work we report novel evidence for the validity of this scenario, using functional renormalization group techniques to determine the renormalization group flow of the Einstein-Hilbert action supplemented by the two-loop counterterm found by Goroff and Sagnotti. The resulting system of beta functions comprises three scale-dependent coupling constants and exhibits a non-Gaußian fixed point which constitutes the natural extension of the one found at the level of the Einstein-Hilbert action. The fixed point exhibits two ultraviolet attractive and one repulsive direction supporting a low-dimensional UV-critical hypersurface. Our result vanquishes the longstanding criticism that asymptotic safety will not survive once a "proper perturbative counterterm" is included in the projection space.
↳ hep-thgr-qchep-phPRL(2016)·186 citations
21*
Constraining the Warm Dark Matter Particle Mass through Ultra-Deep UV Luminosity Functions at z=2
N. Menci (1)🇮🇹 · N.G. Sanchez (2)🇫🇷 · M. Castellano (1)🇮🇹 · A. Grazian (1) ((1) INAF - Osservatorio Astronomico di Roma, (2) Observatoire de Paris, Sorbonne Universite, UPMC Univ. Paris 6)🇮🇹
We compute the mass function of galactic dark matter halos for different values of the Warm Dark Matter (WDM) particle mass m_X and compare it with the abundance of ultra-faint galaxies derived from the deepest UV luminosity function available so far at redshift z~2. The magnitude limit M_UV=-13 reached by such observations allows us to probe the WDM mass functions down to scales close to or smaller than the half-mass mode mass scale ~10^9 M_sun. This allowed for an efficient discrimination among predictions for different m_X which turn out to be independent of the star formation efficiency adopted to associate the observed UV luminosities of galaxies to the corresponding dark matter masses. Adopting a conservative approach to take into account the existing theoretical uncertainties in the galaxy halo mass function, we derive a robust limit m_X>1.8 keV for the mass of thermal relic WDM particles when comparing with the measured abundance of the faintest galaxies, while m_X>1.5 keV is obtained when we compare with the Schechter fit to the observed luminosity function. The corresponding lower limit for sterile neutrinos depends on the modeling of the production mechanism; for instance m_sterile > 4 keV holds for the Shi-Fuller mechanism. We discuss the impact of observational uncertainties on the above bound on m_X. As a baseline for comparison with forthcoming observations from the HST Frontier Field, we provide predictions for the abundance of faint galaxies with M_UV=-13 for different values of m_X and of the star formation efficiency, valid up to z~4.
↳ astro-ph.COgr-qchep-phhep-thApJ(2016)·30 citations
22*
A toolbox to solve coupled systems of differential and difference equations
Jakob Ablinger🇦🇹 · Johannes Bluemlein🇩🇪 · Abilio de Freitas🇩🇪 · Carsten Schneider🇦🇹
We present algorithms to solve coupled systems of linear differential equations, arising in the calculation of massive Feynman diagrams with local operator insertions at 3-loop order, which do {\it not} request special choices of bases. Here we assume that the desired solution has a power series representation and we seek for the coefficients in closed form. In particular, if the coefficients depend on a small parameter $\ep$ (the dimensional parameter), we assume that the coefficients themselves can be expanded in formal Laurent series w.r.t.\ $\ep$ and we try to compute the first terms in closed form. More precisely, we have a decision algorithm which solves the following problem: if the terms can be represented by an indefinite nested hypergeometric sum expression (covering as special cases the harmonic sums, cyclotomic sums, generalized harmonic sums or nested binomial sums), then we can calculate them. If the algorithm fails, we obtain a proof that the terms cannot be represented by the class of indefinite nested hypergeometric sum expressions. Internally, this problem is reduced by holonomic closure properties to solving a coupled system of linear difference equations. The underlying method in this setting relies on decoupling algorithms, difference ring algorithms and recurrence solving. We demonstrate by a concrete example how this algorithm can be applied with the new Mathematica package \texttt{SolveCoupledSystem} which is based on the packages \texttt{Sigma}, \texttt{HarmonicSums} and \texttt{OreSys}. In all applications the representation in $x$ -space is obtained as an iterated integral representation over general alphabets, generalizing Poincaré iterated integrals.
↳ cs.SChep-phhep-thmath-ph+1PoS(2016)·14 citations
23*
Initial Conditions for Inflation - A Short Review
Robert Brandenberger🇨🇦
I give a brief review of the status of research on the nature of initial conditions required to obtain a period of cosmological inflation. It is shown that there is good evidence that in the case of large field models, the inflationary slow-roll trajectory is a local attractor in initial condition space, whereas it is not in the case of small field models.
↳ hep-thastro-ph.COgr-qchep-phInt.J.Mod.Phys.D(2016)·150 citations
24*
Perfect fluids coupled to inhomogeneities in the late Universe
Alexander Zhuk🇺🇦
We consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At such scales, the Universe is highly inhomogeneous and is filled with inhomogeneities in the form of galaxies and the groups of galaxies. We also suggest that the Universe is filled with a perfect fluid, and its fluctuations have peculiar velocities of the same (non-relativistic) order of magnitude as for the inhomogeneities. In this sense, the inhomogeneities (e.g. galaxies) and fluctuations of perfect fluids are coupled with each other. We clarify some important points of this approach and present a brief review of previous studies (e.g. CPL model and Chaplygin gas). We demonstrate that considered perfect fluids which satisfy our approach are really coupled to galaxies concentrating around them. The averaged (over the whole Universe) value of their fluctuations is equal to zero.
↳ gr-qcastro-ph.COhep-phhep-thGrav.Cosmol.(2016)·6 citations
25*
Thermalization and confinement in strongly coupled gauge theories
Takaaki Ishii🇬🇷 · Elias Kiritsis🇫🇷 · Christopher Rosen🇬🇷
Quantum field theories of strongly interacting matter sometimes have a useful holographic description in terms of the variables of a gravitational theory in higher dimensions. This duality maps time dependent physics in the gauge theory to time dependent solutions of the Einstein equations in the gravity theory. In order to better understand the process by which "real world" theories such as QCD behave out of thermodynamic equilibrium, we study time dependent perturbations to states in a model of a confining, strongly coupled gauge theory via holography. Operationally, this involves solving a set of non-linear Einstein equations supplemented with specific time dependent boundary conditions. The resulting solutions allow one to comment on the timescale by which the perturbed states thermalize, as well as to quantify the properties of the final state as a function of the perturbation parameters. We comment on the influence of the dual gauge theory's confinement scale on these results, as well as the appearance of a previously anticipated universal scaling regime in the "abrupt quench" limit.
↳ hep-thhep-phEPJ Web Conf.(2016)·1 citation
26*
Thermal evolution of hybrid stars within the framework of a nonlocal Nambu--Jona-Lasinio model
S. M. de Carvalho🇧🇷 · R. Negreiros🇧🇷 · M. Orsaria🇦🇷 · G. A. Contrera🇦🇷 · F. Weber🇺🇸 · W. Spinella🇺🇸
We study the thermal evolution of neutron stars containing deconfined quark matter in their core. Such objects are generally referred to as quark-hybrid stars. The confined hadronic matter in their core is described in the framework of non-linear relativistic nuclear field theory. For the quark phase we use a non-local extension of the SU(3) Nambu Jona-Lasinio model with vector interactions. The Gibbs condition is used to model phase equilibrium between confined hadronic matter and deconfined quark matter. Our study indicates that high-mass neutron stars may contain between 35 and 40 % deconfined quark-hybrid matter in their cores. Neutron stars with canonical masses of around $1.4 M_{⊙}$ would not contain deconfined quark matter. The central proton fractions of the stars are found to be high, enabling them to cool rapidly. Very good agreement with the temperature evolution established for the neutron star in Cassiopeia A (Cas A) is obtained for one of our models (based on the popular NL3 nuclear parametrization), if the protons in the core of our stellar models are strongly paired, the repulsion among the quarks is mildly repulsive, and the mass of Cas A has a canonical value of $1.4 M_{⊙}$ .
↳ nucl-thastro-ph.HEhep-phPRC(2015)·27 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.