Wed·Mar 22, 2017Wednesday·March 22, 2017

1. 01*

   Modeling chiral criticality

   Bengt Friman🇩🇪 · Gabor Almasi🇩🇪 · Krzysztof Redlich🇵🇱

   We discuss the critical properties of net-baryon-number fluctuations at the chiral restoration transition in matter at nonzero temperature and net-baryon density. The chiral dynamics of quantum chromodynamics (QCD) is modeled by the Polykov-loop extended Quark-Meson Lagrangian, that includes the coupling of quarks to temporal gauge fields. The Functional Renormalization Group is employed to account for the criticality at the phase boundary. We focus on the ratios of the net-baryon-number cumulants, ${\chi }_B^n$, for $1\le n\le 4$. The results are confronted with recent experimental data on fluctuations of the net-proton number in nucleus-nucleus collisions.

   hep-phActa Phys.Polon.Supp.(2017)·0 citations
2. 02*

   Composite Dark Matter and Higgs

   Teng Ma🇨🇳 · Yongcheng Wu🇨🇦 · Bin Zhang🇨🇳 · Giacomo Cacciapaglia🇫🇷

   We investigate the possibility that Dark Matter arises as a composite state of a fundamental confining dynamics, together with the Higgs boson. We focus on the minimal SU(4)$\times$SU(4)/SU(4) model which has both a Dark Matter and a Higgs candidates arising as pseudo-Nambu-Goldstone bosons. At the same time, a simple underlying gauge-fermion theory can be defined providing an existence proof of, and useful constraints on, the effective field theory description. We focus on the parameter space where the Dark Matter candidate is mostly a gauge singlet. We present a complete calculation of its relic abundance and find preferred masses between 500 GeV to a few TeV. Direct Dark Matter detection already probes part of the parameter space, ruling out masses above 1 TeV, while Indirect Detection is relevant only if non-thermal production is assumed. The prospects for detection of the odd composite scalars at the LHC are also established.

   hep-phJHEP(2017)·75 citations
3. 03*

   Production of exotic composite quarks at the LHC

   O. Panella🇮🇹 · R. Leonardi🇮🇹 · G. Pancheri🇮🇹 · Y. N. Srivastava🇮🇹 · M. Narain🇺🇸 · U. Heintz🇺🇸

   We consider the production at the LHC of exotic composite quarks of charge $Q=+(5/3)e$ and $Q=-(4/3)e$. Such states are predicted in composite models of higher isospin multiplets ($I_W=1$ or $I_W=3/2$). Given their exotic charges (such as $5/3$), their decays proceed through the electroweak interactions. We compute decay widths and rates for resonant production of the exotic quarks at the LHC. Partly motivated by the recent observation of an excess by the CMS collaboration in the $e/p_{T}jj$ final state signature we focus on $pp\to U^{+}j\to W^{+}+jj\to {\ell }^{+}/p_{T}jj$ and then perform a fast simulation of the detector reconstruction based on DELPHES. We then scan the parameter space of the model ($m_{\ast }=\Lambda$) and study the statistical significance of the signal against the relevant standard model background ($Wjj$ followed by leptonic decay of the $W$ gauge boson) providing the luminosity curves as function of $m_{\ast }$ for discovery at 3- and 5-$\sigma$ level.

   hep-phPRD(2017)·14 citations
4. 04*

   Pentaquark photoproduction

   C. Fernandez-Ramirez🇲🇽 · A.N. Hiller Blin🇪🇸 · A. Pilloni🇺🇸

   We present results and suggestions on how to confirm the existence and resonant nature of the $Pc(4450)$ detected at LHCb through photoproduction experiments. We find that this narrow structure might have escaped detection in past experiments and use those to give a constraint for the upper limit of the branching ratio/coupling to the $J/\psi p$ channel.

   hep-phnucl-thJ.Phys.Conf.Ser.(2017)·4 citations
5. 05*

   Interpretation of the gamma-ray excess and AMS-02 antiprotons: Velocity dependent dark matter annihilations

   Lian-Bao Jia🇨🇳

   The two messenger results of the GeV gamma-ray excess at the Galactic center and a probable antiproton excess in the recent AMS-02 observation suggest that these two anomalies may be owing to the same origin --- the dark matter (DM) annihilation into $b\bar{b}$, while these results seem in tension with the dwarf spheroidal galaxy observations. To give a compatible explanation about it, we consider the pseudoscalar DM particles $S_d^{+}{S}_d^{-}$ annihilating via $S_d^{+}{S}_d^{-}\to S_d^0{S}_d^0$, with the process mediated by a new scalar $\varphi$ and $S_d^0$ quickly decaying into $b\bar{b}$. For the particles $S_d^{+}$, $S_d^{-}$ and $S_d^0$ in a triplet with degenerate masses, the annihilation cross section of DM today is linearly dependent on the relative velocity $v_r$, and thus constraints from the dwarf spheroidal galaxies are relaxed. The parameter spaces are derived with corresponding constraints. Though traces from the new sector seem challenging to be disclosed at collider and in DM direct detections, the indirect search of the gamma-ray line from the $S_d^0$'s decay has the potential to shed light on DM annihilations, with the energy of the gamma-ray line $\sim m_{S_d^0}/2$, i.e. about 50$-$75 GeV.

   hep-phastro-ph.COastro-ph.HEPRD(2017)·12 citations
6. 06*

   On the nature of the newly discovered ${\Omega }_c^0$ states

   S. S. Agaev🇦🇿 · K. Azizi🇹🇷 · H. Sundu🇹🇷

   The masses and residues of the radially excited heavy ${\Omega }_c^0$ and ${\Omega }_b^{-}$ baryons with spin-parity $J^P={\frac{1}{2}}^{+}$ and $J^P={\frac{3}{2}}^{+}$ are calculated by means of QCD two-point sum rule method using the general form of their interpolating currents. In calculations the quark, gluon and mixed vacuum condensates up to ten dimensions are taken into account. In ${\Omega }_c^0$ channel a comparison is made with the narrow excited states recently observed by the LHCb Collaboration.

   hep-phhep-exhep-latEPL(2017)·82 citations
7. 07*

   Longitudinal W boson scattering in a light scalar top scenario

   Koji Ishiwata🇯🇵 · Yuki Yonekura🇯🇵

   Scalar tops in the supersymmetric model affect the potential of the standard model-like Higgs at the quatum level. In light of the equivalence theorem, the deviation of the potential from the standard model can be traced by longitudinal gauge bosons. In this work, high energy longitudinal W boson scattering is studied in a TeV-scale scalar top scenario. O(1-10%) deviation from the standard model prediction in the differential cross section is found depending on whether the observed Higgs mass is explained only by scalar tops or by additional contributions at a higher scale.

   hep-phhep-exPRD(2017)·0 citations
8. 08*

   Two-fermion Bethe-Salpeter Equation in Minkowski Space: the Nakanishi Way

   Giovanni Salme' (INFN-Rome)🇮🇹 · Wayne de Paula (ITA-S. Jose' dos Campos)🇧🇷 · Tobias Frederico (ITA-S. Jose' dos Campos)🇧🇷 · Michele Viviani (INFN-Pisa)🇮🇹

   The possibility of solving the Bethe-Salpeter Equation in Minkowski space, even for fermionic systems, is becoming actual, through the applications of well-known tools: i) the Nakanishi integral representation of the Bethe-Salpeter amplitude and ii) the light-front projection onto the null-plane. The theoretical background and some preliminary calculations are illustrated, in order to show the potentiality and the wide range of application of the method.

   hep-phcond-mat.str-elnucl-thFew Body Syst.(2017)·8 citations
9. 09*

   Matter effects at the T2HK and T2HKK experiments

   Sushant K. Raut🇰🇷

   Determining the neutrino mass hierarchy and measuring the CP-violating phase ${\delta }_{CP}$ are two of the main aims in neutrino physics today. The upcoming T2HK (with small matter effects and high statistics) and DUNE (with large matter effects) experiments have been shown to have excellent sensitivity to ${\delta }_{CP}$ and the neutrino mass hierarchy, respectively. The recent T2HKK proposal aims to improve the hierarchy sensitivity of T2HK by placing one of the two tanks of the HK detector at a site in Korea, to collect data at $\sim 1100$ km baseline. In light of the fact that DUNE will anyway collect data at $\sim 1300$ km, we explore whether it is advantageous to collect additional long-baseline data as proposed with T2HKK, or to enhance the ${\delta }_{CP}$-precision with the `conventional' T2HK by keeping both detector tanks in Japan. We do this by comparing the physics reach of these two options in conjunction with DUNE. We find that DUNE+T2HKK is better at excluding the wrong hierarchy, reaching $\Delta {\chi }^2>175$ irrespective of the true parameters. While DUNE+T2HK can measure ${\delta }_{CP}$ with more precision in some parts of the parameter space, both DUNE+T2HK and DUNE+T2HKK perform equally well near the current best-fit point, giving a ${\delta }_{CP}$ width of around $15^{\circ }$. The T2HKK setup allows us to correlate and constrain the systematic errors between the two detectors collecting data from the same source, which can increase the sensitivity of the experiment by up to 25\%. Such a reduction of the systematic errors is crucial for determining the oscillation parameters with greater significance.

   hep-phPRD(2017)·19 citations
10. 10*

    Can the triple-parton scattering be observed in open charm meson production at the LHC?

    Rafal Maciula🇵🇱 · Antoni Szczurek🇵🇱

    We investigate whether the triple-parton scattering effects can be observed in open charm production in proton-proton collisions at the LHC. We use so-called factorized Ansatz for calculations of hard multiple-parton interactions. The numerical results for each parton interaction are obtained within the $k_T$-factorization approach. Predictions for one, two and three $c\bar{c}$ pairs production are given for $\sqrt{s}=7$ TeV and $\sqrt{s}=13$ TeV. Quite large cross sections, of the order of milibarns, for the triple-parton scattering mechanism are obtained. We suggest a measurement of three $D^0$ mesons or three $\overline{D^0}$ antimesons by the LHCb collaboration. Confronting our results with recent LHCb experimental data for single and double $D^0$ (or $\overline{D^0}$) meson production we present our predictions for triple meson final state: $D^0{D}^0{D}^0$ or $\overline{D^0}\overline{D^0}\overline{D^0}$. We present cross sections for the LHCb fiducial volume as well as distributions for $D^0$ meson transverse momentum and three-$D^0$ meson invariant mass. The predicted visible cross sections, including the detector acceptance, hadronization effects and $c\to D^0$ branching fraction, is of the order of a few nanobarns. The counting rates including $D^0\to K^{-}{\pi }^{+}$ branching fractions are given for known or expected integrated luminosities.

    hep-phhep-exPLB(2017)·18 citations
11. 11*

    Cut and compute: Quick cascades with multiple amplitudes

    Joydeep Chakrabortty🇮🇳 · Anirban Kundu🇮🇳 · Rinku Maji🇮🇳 · Tripurari Srivastava🇮🇳

    In an earlier paper we have proposed a novel method to compute the decay width for a general $1\to n$ cascade decay where the propagators are off-shell and may be of different spins. Here, we extend our algorithm to accommodate those decays that are mediated by more than one such cascades. This generalizes our prescription and widens its applicability. We compute the three- and four-body toy decay chains where identical final states appear through different cascades. Here, we also provide the algorithm to calculate the interference terms. For four-body decays we discuss both symmetric and asymmetric cascades, providing the expressions for the detailed phase space structure in each case. We find that the results obtained with this algorithm have a very impressive agreement with those from standard softwares using a sophisticated Monte Carlo based phase space integration.

    hep-ph2 citations
12. 12*

    Two-body Wave Functions, Compositeness, And The Internal Structure Of Dynamically Generated Resonances

    Takayasu Sekihara (JAEA, Ibaraki)🇯🇵 · Tetsuo Hyodo (Kyoto U., Yukawa Inst., Kyoto)🇯🇵 · Daisuke Jido (Tokyo Metropolitan U.)🇯🇵 · Junko Yamagata-Sekihara (Kyoto Sangyo U.)🇯🇵 · Shigehiro Yasui (Tokyo Inst. Tech.)🇯🇵

    Recently, the compositeness, defined as the norm of a two-body wave function for bound and resonance states, has been investigated to discuss the internal structure of hadrons in terms of hadronic molecular components. From the studies of the compositeness, it has been clarified that the two-body wave function of a bound state can be extracted from the residue of the scattering amplitude at the bound state pole. Of special interest is that the two-body wave function from the scattering amplitude is automatically normalized. In particular, while the compositeness is unity for energy-independent interactions, it deviates from unity for energy-dependent interactions, which can be interpreted as a missing-channel contribution. In this manuscript, we show the formulation of the two-body wave function from the scattering amplitude, evaluate the compositeness for several dynamically generated resonances such as $f_0(980)$, $\Lambda (1405)$, and $\Xi (1690)$, and investigate their internal structure in terms of the hadronic molecular components.

    hep-phhep-exnucl-exnucl-th+1PoS(2017)·0 citations
13. 13*

    Gravitational effects in birefringent quantum electrodynamics

    Simon Grosse-Holz🇩🇪 · Frederic P. Schuller🇩🇪 · Roberto Tanzi🇮🇹

    The most general classical electrodynamics which still respect the linear superposition principle but allow for otherwise arbitrary birefringence require, and imply, a refined spacetime geometry described by a fourth-rank tensor field. Canonical gravitational dynamics for this geometry, if required to co-evolve in causally consistent fashion with the electromagnetic field, were shown to be constructively determined by gravitational closure of the birefringent electromagnetic field equations. For weak gravitational fields of the resulting birefringent refinement of classical Einstein-Maxwell theory, we show in this article that the corresponding quantum electrodynamics is locally renormalizable at every loop order in gauge-invariant fashion and then employ this result to compute various fundamental processes. Combining quantum field theoretic results in locally essentially flat regions with the global spacetime structure predicted by the refined gravitational dynamics, we find that the anomalous magnetic moment of the electron, the cross sections of Bhabha scattering, and the hyperfine splitting of the hydrogen all pick up a dependence on position in the gravitational field. Particularly the measurement of the hyperfine line of hydrogen, but quite generally the measurement of any local quantum electrodynamical process, is thus able to inform the search for vacuum birefringence and its effects in a new way, since the gravitational theory allows to predict where the effects will be most pronounced.

    hep-phgr-qc16 citations
14. 14*

    Exclusive Radiative Decays of Z Bosons in QCD Factorization

    Stefan Alte🇩🇪 · Yuval Grossman🇺🇸 · Matthias König🇩🇪 · Matthias Neubert🇩🇪

    We discuss the very rare, exclusive hadronic decays of a Z boson into a meson and a photon. The QCD factorization approach allows to organize the decay amplitude as an expansion in powers of ${\Lambda }_{\mathrm{QCD}}/m_Z$, where the leading terms contain convolutions of perturbatively calculable hard functions with the leading-twist light-cone distribution amplitudes of the meson. We find that power corrections to these leading terms are negligible since they are suppressed by the small ratio $({\Lambda }_{\mathrm{QCD}}/m_Z{)}^2$. Renormalization-group effects play a crucial role as they render our theoretical predictions less sensitive to the hadronic input parameters which are currently not known very precisely. Thus, measurements of the decays $Z\to M\gamma$ at the LHC or a future lepton collider provide a theoretically very clean way to test the QCD factorization approach. The special case where $M={\eta }^{(}{}^{\prime }{}^{)}$ is complicated by the fact that the decay amplitude receives an additional contribution where the meson is formed from a two-gluon state. The corresponding branching ratios are very sensitive to the hadronic parameters describing the $\eta -{\eta }^{\prime }$ system. Future measurements of these decays could yield interesting information about these parameters and the gluon distribution amplitude.

    hep-phPoS(2016)·5 citations
15. 15*

    A New Bound on Axion-Like Particles

    M.C. David Marsh🇬🇧 · Helen R. Russell🇬🇧 · Andrew C. Fabian🇬🇧 · Brian R. McNamara🇨🇦 · Paul Nulsen🇦🇺 · Christopher S. Reynolds🇺🇸

    Axion-like particles (ALPs) and photons can quantum mechanically interconvert when propagating through magnetic fields, and ALP-photon conversion may induce oscillatory features in the spectra of astrophysical sources. We use deep (370 ks), short frame time Chandra observations of the bright nucleus at the centre of the radio galaxy M87 in the Virgo cluster to search for signatures of light ALPs. The absence of substantial irregularities in the X-ray power-law spectrum leads to a new upper limit on the photon-ALP coupling, $g_{a\gamma }$: using a conservative model of the cluster magnetic field consistent with Faraday rotation measurements from M87 and M84, we find $g_{a\gamma }<2.6\times 10^{-12}$ GeV${}^{-1}$ at 95% confidence level for ALP masses $m_a\le 10^{-13}$ eV. Other consistent magnetic field models lead to stronger limits of $g_{a\gamma }\lesssim 1.1$--$1.5\times 10^{-12}$ GeV${}^{-1}$. These bounds are all stronger than the limit inferred from the absence of a gamma-ray burst from SN1987A, and rule out a substantial fraction of the parameter space accessible to future experiments such as ALPS-II and IAXO.

    hep-phastro-ph.COastro-ph.HEJCAP(2017)·189 citations
16. 16*

    The Waning of the WIMP? A Review of Models, Searches, and Constraints

    Giorgio Arcadi🇩🇪 · Maíra Dutra🇫🇷 · Pradipta Ghosh🇫🇷 · Manfred Lindner🇩🇪 · Yann Mambrini🇫🇷 · Mathias Pierre🇫🇷 · Stefano Profumo🇺🇸 · Farinaldo S. Queiroz🇩🇪

    Weakly Interacting Massive Particles (WIMPs) are among the best-motivated dark matter candidates. In light of no conclusive detection signal yet despite an extensive search program that combines, often in a complementary way, direct, indirect, and collider probes, we find it timely to give a broad overview of the WIMP paradigm. In particular, we review here the theoretical foundations of the WIMP paradigm, discuss status and prospects of various detection strategies, and explore future experimental challenges and opportunities.

    hep-phastro-ph.HEhep-exhep-thEPJC(2018)·1161 citations
17. 17*

    Exclusive $\eta$ electroproduction at $W>2$ GeV with CLAS and transversity generalized parton distributions

    CLAS Collaboration: I. Bedlinskiy🇷🇺 · V. Kubarovsky🇺🇸 · P. Stoler🇺🇸 · K. P. Adhikari🇺🇸 · Z. Akbar🇺🇸 · S. Anefalos Pereira🇮🇹 · H. Avakian🇺🇸 · J. Ball🇫🇷 · N. A. Baltzell🇺🇸 · M. Battaglieri🇮🇹 · V. Batourine🇺🇸 · A. S. Biselli🇺🇸 and 134 other authors

    The cross section of the exclusive $\eta$ electroproduction reaction $ep\to e^{\prime }{p}^{\prime }\eta$ was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections $d^4\sigma /dtd{Q}^{2}d{x}_{B}d{\varphi }_{\eta }$ and structure functions ${\sigma }_U={\sigma }_T+ϵ{\sigma }_L,{\sigma }_{TT}$ and ${\sigma }_{LT}$, as functions of $t$ were obtained over a wide range of $Q^2$ and $x_B$. The $\eta$ structure functions are compared with those previously measured for ${\pi }^0$ at the same kinematics. At low $t$, both ${\pi }^0$ and $\eta$ are described reasonably well by generalized parton distributions (GPDs) in which chiral-odd transversity GPDs are dominant. The ${\pi }^0$ and $\eta$ data, when taken together, can facilitate the flavor decomposition of the transversity GPDs.

    ↳ nucl-exhep-exhep-phPRC(2017)·30 citations
18. 18*

    The MoEDAL experiment at the LHC: status and results

    Vasiliki A. Mitsou (for the MoEDAL Collaboration)🇪🇸

    The MoEDAL experiment at the LHC is optimised to detect highly ionising particles such as magnetic monopoles, dyons and (multiply) electrically charged stable massive particles predicted in a number of theoretical scenarios. MoEDAL, deployed in the LHCb cavern, combines passive nuclear track detectors with magnetic monopole trapping volumes (MMTs), while spallation-product backgrounds are being monitored with an array of MediPix pixel detectors. An introduction to the detector concept and its physics reach, complementary to that of the large general purpose LHC experiments ATLAS and CMS, will be given. Emphasis is given to the recent MoEDAL results at 13 TeV, where the null results from a search for magnetic monopoles in MMTs exposed in 2015 LHC collisions set the world-best limits on particles with magnetic charges more than 1.5 Dirac charge. The potential to search for heavy, long-lived supersymmetric electrically-charged particles is also discussed.

    ↳ hep-exhep-phphysics.ins-detJ.Phys.Conf.Ser.(2017)·25 citations
19. 19*

    Are two nucleons bound in lattice QCD for heavy quark masses? -- Consistency check with Lüscher's finite volume formula --

    Takumi Iritani🇯🇵 · Sinya Aoki🇯🇵 · Takumi Doi🇯🇵 · Tetsuo Hatsuda🇯🇵 · Yoichi Ikeda🇯🇵 · Takashi Inoue🇯🇵 · Noriyoshi Ishii🇯🇵 · Hidekatsu Nemura🇯🇵 · Kenji Sasaki🇯🇵

    On the basis of the Lüscher's finite volume formula, a simple test (consistency check or sanity check) is introduced and applied to inspect the recent claims of the existence of the nucleon-nucleon ($NN$) bound state(s) for heavy quark masses in lattice QCD. We show that the consistency between the scattering phase shifts at $k^2>0$ and/or $k^2<0$ obtained from the lattice data and the behavior of phase shifts from the effective range expansion (ERE) around $k^2=0$ exposes the validity of the original lattice data, otherwise such information is hidden in the energy shift $\Delta E$ of the two nucleons on the lattice. We carry out this sanity check for all the lattice results in the literature claiming the existence of the $NN$ bound state(s) for heavy quark masses, and find that (i) some of the $NN$ data show clear inconsistency between the behavior of ERE at $k^2>0$ and that at $k^2<0$, (ii) some of the $NN$ data exhibit singular behavior of the low energy parameter (such as the divergent effective range) at $k^2<0$, (iii) some of the $NN$ data have the unphysical residue for the bound state pole in S-matrix, and (iv) the rest of the $NN$ data are inconsistent among themselves. Furthermore, we raise a caution of using the ERE in the case of the multiple bound states. Our finding, together with the fake plateau problem previously pointed out by the present authors, brings a serious doubt on the existence of the $NN$ bound states for pion masses heavier than 300 MeV in the previous studies.

    ↳ hep-lathep-phnucl-thPRD(2017)·86 citations
20. 20*

    Projectivity of Planar Zeros in Field and String Theory Amplitudes

    Diego Medrano Jimenez🇪🇸 · Agustin Sabio Vera🇪🇸 · Miguel A. Vazquez-Mozo🇪🇸

    We study the projective properties of planar zeros of tree-level scattering amplitudes in various theories. Whereas for pure scalar field theories we find that the planar zeros of the five-point amplitude do not enjoy projective invariance, coupling scalars to gauge fields gives rise to tree-level amplitudes whose planar zeros are determined by homogeneous polynomials in the stereographic coordinates labelling the direction of flight of the outgoing particles. In the case of pure gauge theories, this projective structure is generically destroyed if string corrections are taken into account. Scattering amplitudes of two scalars with graviton emission vanish exactly in the planar limit, whereas planar graviton amplitudes are zero for helicity violating configurations. These results are corrected by string effects, computed using the single-valued projection, which render the planar amplitude nonzero. Finally, we discuss how the structure of planar zeros can be derived from the soft limit behavior of the scattering amplitudes.

    ↳ hep-thhep-phJHEP(2017)·3 citations
21. 21*

    Enhancing the Spectral Hardening of Cosmic TeV Photons by Mixing with Axionlike Particles in the Magnetized Cosmic Web

    Daniele Montanino🇮🇹 · Franco Vazza🇮🇹 · Alessandro Mirizzi🇮🇹 · Matteo Viel🇮🇹

    Large-scale extragalactic magnetic fields may induce conversions between very-high-energy photons and axionlike particles (ALPs), thereby shielding the photons from absorption on the extragalactic background light. However, in simplified "cell" models, used so far to represent extragalactic magnetic fields, this mechanism would be strongly suppressed by current astrophysical bounds. Here we consider a recent model of extragalactic magnetic fields obtained from large-scale cosmological simulations. Such simulated magnetic fields would have large enhancement in the filaments of matter. As a result, photon-ALP conversions would produce a significant spectral hardening for cosmic TeV photons. This effect would be probed with the upcoming Cherenkov Telescope Array detector. This possible detection would give a unique chance to perform a tomography of the magnetized cosmic web with ALPs.

    ↳ astro-ph.HEastro-ph.COhep-phPRL(2017)·40 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.