Thu·Apr 30, 2020Thursday·April 30, 2020

1. 01*

   Polarized $q\bar{q}\to Z+$Higgs amplitudes at two loops in QCD: the interplay between vector and axial vector form factors and a pitfall in applying a non-anticommuting ${\gamma }_5$

   Taushif Ahmed🇩🇪 · Werner Bernreuther🇩🇪 · Long Chen🇩🇪 · Michal Czakon🇩🇪

   We consider QCD corrections to two loops for the polarized amplitudes of $q\bar{q}\to Z+$ Higgs boson. First we show how the polarized amplitudes of $b\bar{b}\to Zh$ associated with a non-vanishing $b$-quark Yukawa coupling and a scalar or pseudoscalar Higgs boson $h$ can be built up solely from vector form factors (FF) of properly grouped classes of diagrams, bypassing completely the need of explicitly manipulating ${\gamma }_5$ in dimensional regularization (up to a few "anomalous", i.e., triangle diagrams). We determine the contributions of the triangle diagrams in the heavy top limit. We present the analytic results of the vector FF and the triangle-diagram contributions to the axial vector FF, which are sufficient for deriving the two-loop QCD amplitudes for $b\bar{b}\to Zh$ with a CP-even and CP-odd Higgs boson $h$. We derive the respective Ward identity for these amplitudes, which are subsequently verified to two-loop order in QCD using these FF. In addition, the FF of a class of corrections to $q\bar{q}\to ZH$ proportional to the top-Yukawa coupling are obtained analytically to two-loop order in QCD in the heavy-top limit using the Higgs-gluon effective Lagrangian where the top quark is integrated out. We address a pitfall that occurs when applying the non-anticommutating ${\gamma }_5$ prescription to this class of contributions that has been overlooked so far in the literature. We attribute this issue to the fact that the absence of certain heavy-mass expanded diagrams in the infinite-mass limit of a scattering amplitude with an axial vector current depends on the particular ${\gamma }_5$ prescription in use.

   hep-phhep-thJHEP(2020)·18 citations
2. 02*

   Scalar dark matter and leptogenesis in the minimal scotogenic model

   Lavina Sarma🇮🇳 · Pritam Das🇮🇳 · Mrinal Kumar Das🇮🇳

   We study the minimal scotogenic model constituting an additional inert Higgs doublet and three sets of right-handed neutrinos. The scotogenic model connects dark matter, baryon asymmetry of the Universe and neutrino oscillation data. In our work, we obtain baryogenesis by the decay of TeV scale heavy neutral singlet fermion ($N_2$). We primarily focus on the intermediate-mass region of dark matter within $M_W<M_{DM}\le 550$ GeV, where observed relic density is suppressed due to co-annihilation processes. We consider thermal as well as the non-thermal approach of dark matter production and explore the possibility of the lightest stable candidate being a dark matter candidate. Within the inert Higgs doublet (IHD) desert, we explore a new allowed region of dark matter masses for the non-thermal generation of dark matter with a mass splitting of 10 GeV among the inert scalars. We also see the variation of relic abundance for unequal mass splitting among the scalars. The KamLand-Zen bound on the effective mass of the active neutrinos is also verified in this study.

   hep-phNPB(2021)·27 citations
3. 03*

   Scalar and tensor neutrino interactions

   Tao Han🇺🇸 · Jiajun Liao🇨🇳 · Hongkai Liu🇺🇸 · Danny Marfatia🇺🇸

   We constrain general Dirac neutrino interactions based on the Standard Model Effective Field Theory framework extended with right-handed neutrinos $N$ (SMNEFT) using deep inelastic and coherent elastic neutrino scattering, nuclear beta decay, and meson decay data, and high energy electron-proton and proton-proton collider data. We compute the one-loop anomalous dimensions of the low-energy effective field theory (LEFT) below the electroweak scale and of SMNEFT above the electroweak scale. The tree-level matching between LEFT and SMNEFT is performed at the electroweak scale. Currently, the most stringent limits on scalar and tensor interactions arise from pseudoscalar meson decays and the LHC measurements at the per mille level. In the future, the upcoming High-Luminosity LHC (HL-LHC) has the potential to reach the $10^{-4}$ level and LHeC can play an important role under certain theoretical assumptions.

   hep-phhep-exJHEP(2020)·50 citations
4. 04*

   Strongly-interacting massive particle and dark photon in the era of intensity frontier

   Ayuki Kamada🇰🇷 · Masaki Yamada🇯🇵 · Tsutomu T. Yanagida🇨🇳

   A strongly interacting massive particle (SIMP) is an interesting candidate for dark matter (DM) because its self-interaction cross section can be naturally strong enough to address the astrophysical problem of small-scale structure formation. A simple model was proposed by assuming a monopole condensation, where composite SIMP comes from a "strongly interacting" U(1)${}_{\mathrm{d}}$ gauge theory. In the original model, the DM relic abundance is determined by the $3\to 2$ annihilation process via the Wess-Zumino-Witten term. In this letter, we discuss that the DM relic abundance is naturally determined also by a semi-annihilation process via a kinetic mixing between the hypercharge gauge boson and the dark U(1)${}_{\mathrm{d}}$ gauge boson (dark photon). The dark photon can be discovered by LDMX-style missing momentum experiments in the near future.

   hep-phastro-ph.COPRD(2020)·4 citations
5. 05*

   Studying the $D_{1}D$ molecule in the Bethe-Salpeter equation approach

   Zhen-Yang Wang🇨🇳 · Jing-Juan Qi🇨🇳 · Jing Xu🇨🇳 · Xin-Heng Guo🇨🇳

   We study the possible bound states of the $D_{1}D$ system in the Bethe-Salpeter (BS) formalism in the ladder and instantaneous approximations. By solving the BS equation numerically with the kernel containing one-particle exchange diagrams and introducing three different form factors (monopole, dipole, and exponential form factors) at the vertices, we investigate whether the isoscalar and isovector $D_{1}D$ bound states may exist, respectively. We find that $Y(4260)$ could be accommodated as a $D_{1}D$ molecule, whereas the interpretation of $Z_2^{+}(4250)$ as a $D_{1}D$ molecule is disfavored. The bottom analog of $Y(4260)$ may exist but that of $Z_2^{+}(4250)$ does not.

   hep-phPRD(2020)·9 citations
6. 06*

   Threshold effects on prediction for proton decay in non-supersymmetric $E_6$ GUT with intermediate trinification symmetry

   Chandini Dash🇮🇳 · Snigdha Mishra (Berhampur U.)🇮🇳 · Sudhanwa Patra🇮🇳 · Purushottam Sahu (Indian Inst. Tech., Bhilai)🇮🇳

   We consider a non-supersymmetric $E_6$ Grand Unified Theory (GUT) with intermediate trinification symmetry $SU(3{)}_C\times SU(3{)}_L\times SU(3{)}_R\times D$ (D denoted as D-parity for discrete left-right symmetry) and study the effect of one-loop threshold corrections arising due to every class of superheavy particles (scalars, fermions and vectors). It is observed that, the intermediate mass scale $M_I$ and ${\sin }^2{\theta }_W$ remain unaffected by GUT threshold contributions. The threshold modified unification mass scale $M_U$ is in excellent agreement with the present experimental proton decay constraint. The novel feature of the model is that GUT threshold uncertainty of $M_U$ is found to be controlled by superheavy scalars only, leading to a very predictive scenario for proton decay, which can be verifiable within the foreseeable experiments.

   hep-phNPB(2021)·7 citations
7. 07*

   Leptogenesis from a $U(1{)}_D$ resonance

   E. J. Chun🇰🇷 · Arnab Dasgupta🇰🇷 · Sin Kyu Kang🇰🇷

   We propose a novel mechanism to realize leptogenesis through the Breit-Wigner resonance of a dark $U(1{)}_D$ gauge boson $Z_D$, which mediates lepton number violating annihilations of dark matter (DM) in the context of the scotogenic model with a $U(1{)}_D$. The processes occur out of equilibrium and the DM freezes out lately giving rise to the observed abundance. The CP violation required for leptogenesis can be achieved by the interference between tree-level t-channel scattering of DM and the subsequent 1-loop mediated by $Z_D$, which arises due to the unremovable imaginary part of either the $Z_D$ propagator coming from its self-energy correction or the 1-loop giving rise to the effective coupling of $Z_D\bar{\nu }\nu$.

   hep-phJHEP(2020)·3 citations
8. 08*

   Neutrino mass, mixing and muon $g-2$ explanation in $U(1{)}_{L_{\mu }-L_{\tau }}$ extension of left-right theory

   Chayan Majumdar🇮🇳 · Sudhanwa Patra🇮🇳 · Prativa Pritimita🇮🇳 · Supriya Senapati🇮🇳 · Urjit A Yajnik🇮🇳

   We consider a gauged $U(1{)}_{L_{\mu }-L_{\tau }}$ extension of the left-right symmetric theory in order to simultaneously explain neutrino mass, mixing and the muon anomalous magnetic moment. We get sizeable contribution from the interaction of the new light gauge boson $Z_{\mu \tau }$ of the $U(1{)}_{L_{\mu }-L_{\tau }}$ symmetry with muons which can individually satisfy the current bounds on muon $(g-2)$ anomaly ($\Delta a_{\mu }$). The other positive contributions to $\Delta a_{\mu }$ come from the interactions of singly charged gauge bosons $W_L$, $W_R$ with heavy neutral fermions and that of neutral CP-even scalars with muons. The interaction of $W_L$ with heavy neutrino is facilitated by inverse seesaw mechanism which allows large light-heavy neutrino mixing and explains neutrino mass in our model. CP-even scalars with mass around few hundreds GeV can also satisfy the entire current muon anomaly bound. The results show that the model gives a small but non-negligible contribution to $\Delta a_{\mu }$ thereby eliminating the entire deviation in theoretical prediction and experimental result of muon $(g-2)$ anomaly. We have briefly presented a comparative study for symmetric and asymmetric left-right symmetric model in context of various contribution to $\Delta a_{\mu }$. We also discuss how the generation of neutrino mass is affected when left-right symmetry breaks down to Standard Model symmetry via various choices of scalars.

   hep-phJHEP(2020)·18 citations
9. 09*

   The three-dimensional distribution of quarks in momentum space

   Alessandro Bacchetta🇮🇹 · Filippo Delcarro🇺🇸 · Cristian Pisano🇮🇹 · Marco Radici🇮🇹

   We present the distribution of unpolarized quarks in a transversely polarized proton in three-dimensional momentum space. Our results are based on consistent extractions of the unpolarized and Sivers transverse momentum dependent parton distributions (TMDs).

   hep-phnucl-thPLB(2022)·85 citations
10. 10*

    A Mellin Transform Approach to Rephasing Invariants

    Jean-François Fortin🇨🇦 · Nicolas Giasson🇨🇦 · Luc Marleau🇨🇦 · Jasmine Pelletier-Dumont🇨🇦

    In the low-energy effective theory of neutrinos, the Haar measure for unitary matrices is very likely to give rise to the observed PMNS matrix. Assuming the Haar measure, we determine the probability density functions for all quadratic, quartic Majorana, and quartic Dirac rephasing invariants for an arbitrary number of neutrino generations. We show that for a fixed number of neutrinos, all rephasing invariants of the same type have the same probability density function under the Haar measure. We then compute the moments of the rephasing invariants to determine, with the help of the Mellin transform, the three probability density functions. We finally investigate the physical implications of our results in function of the number of neutrinos.

    hep-phPRD(2020)·4 citations
11. 11*

    Complete NLO QCD study of single- and double-quarkonium hadroproduction in the colour-evaporation model at the Tevatron and the LHC

    Jean-Philippe Lansberg🇫🇷 · Hua-Sheng Shao🇫🇷 · Nodoka Yamanaka🇺🇸 · Yu-Jie Zhang🇨🇳 · Camille Noûs🇫🇷

    We study the Single-Parton-Scattering (SPS) production of double quarkonia (J/psi+J/psi, J/psi+Upsilon, and Upsilon+Upsilon) in pp and pp(bar) collisions at the LHC and the Tevatron as measured by the CMS, ATLAS, LHCb, and D0 experiments in the Colour-Evaporation Model (CEM), based on the quark-hadron-duality, including Next-to-Leading Order (NLO) QCD corrections up to alpha_s^5. To do so, we also perform the first true NLO --up to alpha_s^4-- study of the p_T-differential cross section for single-quarkonium production. This allows us to fix the non-perturbative CEM parameters at NLO accuracy in the region where quarkonium-pair data are measured. Our results show that the CEM at NLO in general significantly undershoots these experimental data and, in view of the other existing SPS studies, confirm the need for Double Parton Scattering (DPS) to account for the data. Our NLO study of single-quarkonium production at mid and large p_T also confirms the difficulty of the approach to account for the measured p_T spectra; this is reminiscent of the impossibility to fit single-quarkonium data with the sole 3S18 NRQCD contribution from gluon fragmentation. We stress that the discrepancy occurs in a kinematical region where the new features of the improved CEM are not relevant.

    hep-phhep-exnucl-exnucl-thPLB(2020)·44 citations
12. 12*

    Unveiling complex vector dark matter by magnetic field

    Emin Nugaev🇷🇺 · Andrey Shkerin🇨🇭

    We discuss the possibility that dark matter is made of a new complex massive vector field with a global $U(1)$-symmetry. The field interacts with the Standard Model via coupling to the gauge field of the hypercharge group. We study classical homogeneous configurations arising in the theory. Some of these configurations include magnetic components of the Standard Model electromagnetic field tensor. This opens a possibility to relate the origin of possible primordial magnetic fields to the cosmological evolution of vector dark matter condensates composed of magnetic bosons.

    hep-phastro-ph.HEhep-th4 citations
13. 13*

    Critical point fluctuations: Finite size and global charge conservation effects

    Roman V. Poberezhnyuk🇺🇦 · Oleh Savchuk🇺🇦 · Mark I. Gorenstein🇺🇦 · Volodymyr Vovchenko🇺🇸 · Kirill Taradiy🇩🇪 · Viktor V. Begun🇵🇱 · Leonid Satarov🇩🇪 · Jan Steinheimer🇩🇪 · Horst Stoecker🇩🇪

    We investigate simultaneous effects of finite system size and global charge conservation on thermal fluctuations in the vicinity of a critical point. For that we consider a finite interacting system which exchanges particles with a finite reservoir (thermostat), comprising a statistical ensemble that is distinct from the common canonical and grand canonical ensembles. As a particular example the van der Waals model is used. The global charge conservation effects strongly influence the cumulants of particle number distribution when the system size is comparable to that of the reservoir. If the system size is large enough to capture all the physics associated with the interactions, the global charge conservation effects can be accurately described and corrected for analytically, within a recently developed subensemble acceptance method. The finite size effects start to play a significant role when the correlation length grows large due to proximity of the critical point or when the system is small enough to be comparable to an eigenvolume of an individual particle. We discuss our results in the context of fluctuation measurements in heavy-ion collisions.

    hep-phnucl-exnucl-thPRC(2020)·31 citations
14. 14*

    Dimensional Regularization and Breitenlohner-Maison / 't Hooft-Veltman Scheme for ${\gamma }_5$ applied to Chiral YM Theories: Full One-Loop Counterterm and RGE Structure

    Hermès Bélusca-Maïto (1)🇭🇷 · Amon Ilakovac (1)🇭🇷 · Marija Ma{\dj}or-Božinović (1)🇭🇷 · Dominik Stöckinger (2) ((1) Department of Physics, University of Zagreb, Croatia, (2) Institut für Kern- und Teilchenphysik, TU Dresden, Germany)🇩🇪

    We study the application of the Breitenlohner-Maison-'t Hooft-Veltman (BMHV) scheme of Dimensional Regularization to the renormalization of chiral gauge theories, focusing on the specific counterterm structure required by the non-anticommuting Dirac ${\gamma }_5$ matrix and the breaking of the BRST invariance. Calculations are performed at the one-loop level in a massless chiral Yang-Mills theory with chiral fermions and real scalar fields. We discuss the setup and properties of the regularized theory in detail. Our central results are the full counterterm structures needed for the correct renormalization: the singular UV-divergent counterterms, including evanescent counterterms that have to be kept for consistency of higher-loop calculations. We find that the required singular, evanescent counterterms associated with vector and scalar fields are uniquely determined but are not gauge invariant. Furthermore, using the framework of algebraic renormalization, we determine the symmetry-restoring finite counterterms, that are required to restore the BRST invariance, central to the consistency of the theory. These are the necessary building blocks in one-loop and higher-order calculations. Finally, renormalization group equations are derived within this framework, and the derivation is compared with the more customary calculation in the context of symmetry-invariant regularizations. We explain why, at one-loop level, the extra BMHV-specific counterterms do not change the results for the RGE. The results we find complete those that have been obtained previously in the literature in the absence of scalar fields.

    hep-phhep-thJHEP(2020)·59 citations
15. 15*

    Kaluza-Klein FIMP Dark Matter in Warped Extra-Dimensions

    Nicolás Bernal🇨🇴 · Andrea Donini🇪🇸 · Miguel G. Folgado🇪🇸 · Nuria Rius🇪🇸

    We study for the first time the case in which Dark Matter (DM) is made of Feebly Interacting Massive Particles (FIMP) interacting just gravitationally with the standard model particles in an extra-dimensional Randall-Sundrum scenario. We assume that both the dark matter and the standard model are localized in the IR-brane and only interact via gravitational mediators, namely the graviton, the Kaluza-Klein gravitons and the radion. We found that in the early Universe DM could be generated via two main processes: the direct freeze-in and the sequential freeze-in. The regions where the observed DM relic abundance is produced are largely compatible with cosmological and collider bounds.

    hep-phastro-ph.COJHEP(2020)·39 citations
16. 16*

    Gauge Field Localization in the Linear Dilaton Background

    K. Farakos🇬🇷 · A. Kehagias🇬🇷 · G. Koutsoumbas🇬🇷

    We study dynamical self-localization of gauge theories in higher dimensions. Specifically, we consider a 5D $U(1)$ gauge theory in the linear dilaton (clockwork) background, with anisotropic gauge couplings along the transverse (fifth) direction and the longitudinal (four-dimensional) directions. By using lattice techniques, we calculate the space plaquettes and the helicity moduli and we determine the phase diagram of the model. We find strong evidence that the model exhibits a new phase, a layer phase, where the four-dimensional physics decouples from the five-dimensional dynamics. The layer phase corresponds to a strong force along the fifth direction and a Coulomb phase along the four-dimensional longitudinal directions. This is in accordance with the clockwork mechanism where light particles with exponentially suppressed interactions are generated in theories with no fundamental small parameters.

    hep-phhep-lathep-thPLB(2020)·4 citations
17. 17*

    Cosmic Filaments from Cosmic Strings

    M.A. Fernandez🇺🇸 · Simeon Bird🇺🇸 · Yanou Cui🇺🇸

    Cosmic strings are generically predicted in many extensions of the Standard Model of particle physics. We propose a new avenue for detecting cosmic strings through their effect on the filamentary structure in the cosmic web. Using cosmological simulations of the density wake from a cosmic string, we examine a variety of filament structure probes. We show that the largest effect of the cosmic string is an overdensity in the filament distribution around the string wake. The signal from the overdensity is stronger at higher redshift, and more robust with a wider field. We analyze the spatial distribution of filaments from a publicly available catalog of filaments built from SDSS galaxies. With existing data, we find no evidence for the presence of a cosmic string wake with string tension parameter $G\mu$ above $5\times 10^{-6}$. However, we project WFIRST will be able to detect a signal from such a wake at the $99\%$ confidence level at redshift $z=2$, with significantly higher confidence and the possibility of probing lower tensions ($G\mu \sim 10^{-6}$), at $z=10$. The sensitivity of this method is not competitive with constraints derived from the CMB. However, it provides an independent discovery channel at low redshift, which could be a smoking-gun in scenarios where the CMB bound can be weakened.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2020)·12 citations
18. 18*

    Extra-Natural Inflation (De)constructed

    Kazuyuki Furuuchi🇮🇳 · Noel Jonathan Jobu🇮🇳 · Suvedha Suresh Naik🇮🇳

    Extra-natural inflation is (de)constructed. Explicit models are compared with cosmological observations. The models successfully achieve trans-Planckian inflaton field excursions.

    ↳ hep-thastro-ph.COhep-ph6 citations
19. 19*

    Heavy-ion physics: freedom to do hot, dense, exciting QCD

    Maria Elena Tejeda-Yeomans🇲🇽

    In these two lectures I review the basics of heavy-ion collisions at relativistic energies and the physics we can do with them. I aim to cover the basics on the kinematics and observables in heavy-ion collider experiments, the basics on the phenomenology of the nuclear matter phase diagram, some of the model building and simulations currently used in the heavy-ion physics community and a selected list of amazing phenomenological discoveries and predictions.

    ↳ nucl-thhep-phnucl-exCERN Yellow Rep.School Proc.(2021)·11 citations
20. 20*

    Asymptotic Stability Analysis for $SU(n)$ Dark Monopoles

    M.L. Deglmann🇧🇷 · Marco A.C. Kneipp🇧🇷

    We analyze the asymptotic stability of the $SU(n)$ Dark Monopole solutions and we show that there are unstable modes associated with them. We obtain the explicit form of the unstable perturbations and the associated negative-squared eigenfrequencies.

    ↳ hep-thhep-phPLB(2020)·2 citations
21. 21*

    Pomeron-LQCD model of $J/\Psi$ photo-production on the nucleon

    T.-S. H. Lee🇺🇸

    Based on the vector meson dominance assumption, a Hamiltonian model has been developed to investigate $J/\Psi$ photo-production reaction on the nucleon by using the $J/\Psi$-nucleon potential extracted from a lattice QCD calculation of Phys. Rev. D{\bf 82}, 091501 (2010). It is found that the predicted total cross sections are comparable to the recent data of $J/\Psi$ photo-production reaction from Jefferson Laboratory. The model is then extended to include the two-gluon exchange amplitude modeled by Donnachie and Lanshoff within Regge Phenomenology. The resulting Pomeron-LQCD model can then explain the data up to invariant mass $W=$ 300 GeV. Future improvements needed to reduce the uncertainties of the predictions are discussed. The need of an accurate extraction of $J/\Psi$-N potential at short distances from LQCD is illustrated.

    ↳ nucl-thhep-lathep-phnucl-ex5 citations
22. 22*

    Searching for a Black Hole in the Outer Solar System

    Edward Witten🇺🇸

    There are hints of a novel object ("Planet 9") with a mass $5-10$ $M_{\oplus }$ in the outer Solar System, at a distance of order 500 AU. If it is a relatively conventional planet, it can be found in telescopic searches. Alternatively, it has been suggested that this body might be a primordial black hole (PBH). In that case, conventional searches will fail. A possible alternative is to probe the gravitational field of this object using small, laser-launched spacecraft, like the ones envisioned in the Breakthrough Starshot project. With a velocity of order $.001c$, such spacecraft can reach Planet 9 roughly a decade after launch and can discover it if they can report timing measurements accurate to $10^{-5}$ seconds back to Earth.

    ↳ astro-ph.EPhep-phhep-th28 citations
23. 23*

    Mixed phase transition from hypernuclear matter to deconfined quark matter fulfilling mass-radius constraints of neutron stars

    M. Shahrbaf🇮🇷 · D. Blaschke🇵🇱 · S. Khanmohamadi🇮🇷

    A recent solution of the hyperon puzzle by a first order phase transition to color superconducting quark matter is revisited in order to replace the Maxwell construction by an interpolation method which describes a mixed phase. To do this, we apply for the first time the finite-range polynomial interpolation method for constructing a transition between hadronic and quark matter phases to the situation that is characterized in the literature as the reconfinement problem. For the description of the hadronic phase the lowest order constrained variational method is used while for the quark phase the nonlocal Nambu-Jona-Lasinio model with constant (model nlNJLA) and with density-dependent (model nlNJLB) parameters is employed. Applying the replacement interpolation method to both quark matter models results in a hybrid equation of state that allows a coexistence of nuclear matter, hypernuclear matter and quark matter in a mixed phase between the pure hadronic and quark phases which can also be realized in the structure of the corresponding hybrid star sequences. The predicted hybrid stars fulfill the constraints on the mass-radius relation for neutron stars obtained from recent observations.

    ↳ nucl-thastro-ph.HEhep-phJ.Phys.G(2020)·22 citations
24. 24*

    Predictions and Outcomes for the Dynamics of Rotating Galaxies

    Stacy McGaugh🇺🇸

    A review is given of a priori predictions made for the dynamics of rotating galaxies. One theory - MOND - has had many predictions corroborated by subsequent observations. While it is sometimes possible to offer post hoc explanations for these observations in terms of dark matter, it is seldom possible to use dark matter to predict the same phenomena.

    ↳ astro-ph.GAastro-ph.COhep-phGalaxies(2020)·71 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.