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The ALICE Collaboration has made the first measurement at the LHC of J/ψ photoproduction in ultra-peripheral Pb–Pb collisions at sNN=2.76 TeV. The J/ψ is identified via its dimuon decay in the forward rapidity region with the muon spectrometer for events where the hadronic activity is required to be minimal. The analysis is based on an event sample corresponding to an integrated luminosity of about 55 μb−1. The cross section for coherent J/ψ production in the rapidity interval −3.6<y<−2.6 is measured to be dσJ/ψcoh/dy=1.00±0.18(stat)−0.26+0.24(syst) mb. The result is compared to theoretical models for coherent J/ψ production and found to be in good agreement with those models which include nuclear gluon shadowing.
Direct photon production at mid-rapidity in Pb–Pb collisions at √sNN=2.76 TeV was studied in the transverse momentum range 0.9<pT<14 GeV/c. Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the ALICE detector material with the e+e− pair reconstructed in the central tracking system. The results of the two methods were combined and direct photon spectra were measured for the 0–20%, 20–40%, and 40–80% centrality classes. For all three classes, agreement was found with perturbative QCD calculations for pT≳5 GeV/c. Direct photon spectra down to pT≈1 GeV/c could be extracted for the 20–40% and 0–20% centrality classes. The significance of the direct photon signal for 0.9<pT<2.1 GeV/c is 2.6σ for the 0–20% class. The spectrum in this pT range and centrality class can be described by an exponential with an inverse slope parameter of (297±12stat±41syst) MeV. State-of-the-art models for photon production in heavy-ion collisions agree with the data within uncertainties.
Nomenclatural errors associated with the nymphalid butterfly, Speyeria atlantis greyi Moeck, have persisted in the literature and electronic databases. We present here a synonymy of the various combinations and misspellings associated with it and clearly indicate the correct name and spelling based on Moecks (1950) original description. Additionally, color images of the holotype and allotype specimens are published herein for the first time.
Twenty-two species of Strymon are known from the vicinity of Cacaulandia in Rondonia, Brazil, of which 14 are new species. These belong to 5 species groups: the "oreala" group [Strymon megarus (Godart)]; the "ziba" group [Strymon ziba (Hewitson), Strymon thulia (Hewitson), Strymon spinatus new species, Strymon latamaculus new species, Strymon pallidulus new species, Stlymon tholus new species]; "valentina" group [Strymon rotundum new species]; "crossoea" group [Strymon crossoea (Hewitson), Strymon crambusa (Hewitson), Stlymon germana new species, Strymon novasignum new species, Strymon clavus new species, Strymon implexus new species, Strymon inmirum new species, Strymon incanus new species, Strymon faunalia (Hewitson), Strymon halos new species, Strymon conspergus new species, Strymon bazochii (Godart), Strymon diagonalis new species]; and "eurytulus" group [Strymon bubastus (Stoll)]. Tentative subgroups of species are suggested for the "crossoea" group as they occur in Rondonia. A neotype is designated for Tmolus basilides and the name synonymized with Strymon megarus. The "basilides" group of Johnson et al. (1990) is renamed the "ziba" group. Based on lectotype designations and superficial and genital differences, S. ziba and S. thu.lia are elevated to specific status.
The species of Gigantombra and Angulopis encountered in the Caca ulandia area of central Rondonia, Brazil, are reviewed. These include ten species (all new) of Gigantombra (G. microserrata, G. dl:vergens, G. quadramacula, G. ampla, G. fuscafascia, G. silva, G. rondonia, G. obscura, G. pelplexa, G. pUlpura) and one new species of Angulo pis (A. tenuis). Thecla sangala Hewitson (1868) is recognized as having priority over Theela autoelea Hewitson (1863-1878 [1877]), new synonym. Rondonia continues to appear as a center ofthecline endemism and to provide abundant examples of sibling species diversity.
The pyrgine genus Porphyrogenes Watson, 1893 (Hesperiidae) is discussed, especially as it occurs in central Rondônia, Brazil. Of eleven species of Porphyrogenes found in Rondônia, four (P. specularis, P. convexus, P. sparus, and P. spadix) are described as new species. Biological details of the genus are discussed. An additional five new species of Porphyrogenes (P. spina, P. sporta, P. splendidus, P. simulator, and P. speciosus) are described from elsewhere. Porphyrogenes cervinus (Plötz, 1883), new synonym of Porphyrogenes ferruginea (Plötz, 1883), reinstated status, is raised from a subspecies of Porphyrogenes despecta (Butler, 1870) to species-level. Porphyrogenes omphale (Butler, 1871), reinstated status, is not synonymous with Porphyrogenes passalus (Herrich-Schäffer, 1869) and becomes a species-level taxon for which no subspecies are recognized; P. passalus was described from a female with no known male. Porphyrogenes sula Williams and Bell, 1940, reinstated status, is raised from synonymy with Porphyrogenes zohra (Möschler, 1879) to species-level. Porphyrogenes stresa Evans, 1952, new status, is raised from a subspecies of P. zohra to species-level. Porphyrogenes immaculata (Skinner, 1920), new synonymy, was described from a male, which we believe is the male of Porphyrogenes sororcula (Mabille and Boullet, 1912). Porphyrogenes suva Evans, 1952, new synonymy, formerly considered a full species, was described from a male which we believe is the male of, and thus synonymous with, Porphyrogenes probus (Möschler, 1877). Porphyrogenes virgatus (Mabille, 1888) and Porphyrogenes eudemus (Mabille, 1888), considered synonyms of P. zohra and Porphyrogenes vulpecula (Plötz, 1882), respectively, without justification by Evans (1952), are removed from those synonymies and retained, along with P. passalus, as females without confirmed affinities. Lectotypes are here designated for Phareas ferruginea Plötz, 1883; Augiades despecta Butler, 1870; Telegonus omphale Butler, 1871; Eudamus pausias Hewitson, 1867; Telegonus probus Möschler, 1877; Telemiades vulpecula Plötz, 1882; Eudamus passalus Herrich-Schäffer, 1869; Thymele virgatus Mabille, 1888; and Thymele eudemus Mabille, 1888. A neotype is designated for Phareas cervinus Plötz, 1883, that being the lectotype of Phareas ferruginea. Types of all taxa in the genus are illustrated. Three named and five unnamed phenotypes of females, not reconciled with males, are identified and described. Twenty-six species are now recognized, making this one of the largest hesperiid genera in the neotropics.
Nineteen species of crepuscular and perhaps nocturnal eudamine skippers (Lepidoptera: Hesperiidae) included in Evans (1952) group "D" genera Bungalotis Watson, Salatis Evans, Sarmientoia Berg, Dyscophellus Godman and Salvin, and Nascus Watson occur in the Cacaulândia area of central Rondônia, Brazil. Their relative abundance and phenology there are given. Taxonomic comments and comparisons with published information are made. Bungalotis lactos Evans, 1952, new status, is considered a species separate from Bungalotis borax Evans, 1952. New genera Nicephellus and Euriphellus are proposed for Eudamus nicephorus Hewitson, 1876, and Papilio euribates Stoll, 1782, respectively, removing both from Dyscophellus and creating new combinations. Discophellus porsena Bell, 1934, reinstated status, is raised from synonymy to a full species of Dyscophellus. The subspecies of Dyscophellus ramusis (Stoll, 1781), as presently recognized, are probably good species; Dyscophellus ramon Evans, 1952, new status, is considered a full species. Pseudonascus, new genus, is proposed for Papilio paulliniae Sepp, [1842], removing this species from Nascus and creating a new combination. Two new species, Bungalotis aureus from Ecuador and Dyscophellus mielkei from Rondônia, Brazil, are described. Male and female genitalia are illustrated for all taxa available from the Rondonian study site plus some from other areas.
Eight species of Celaenorrhinus (Hesperiidae: Pyrginae) occur near Cacaulhdia in central Rondonia, Brazil. Three of these represent unnamed species and are described as new: Celaenorrhinus orneates Austin, Celaenorrhinus par Steinhauser & Austin, and Celaenorrhinus autochton Steinhauser & Austin. The male of C. saviais described for the first time. Both sexes of all 8 species (except female C. orneates) and their genitalia are illustrated. Males of C. savia and C. orneates are similar to C. jao in lacking tibial tufts, modified thoracic scales, and abdominal pouches; C. autochton lacks tibial tufts and modified thoracic scales. This adds to the diversity of secondary sexual characters among New World Celaenorrhinus. The following taxa, treated by Evans (1952) as subspecies, are raised to specific rank: C. shema disjunctus Bell, 1940; C. similis stola Evans, 1952; C. similis approximatus Williams & Bell, 1940; and C. similis bifurcus Bell, 1934.
A measurement of the transverse momentum spectra of jets in Pb-Pb collisions at sNN−−−√=2.76 TeV is reported. Jets are reconstructed from charged particles using the anti-kT jet algorithm with jet resolution parameters R of 0.2 and 0.3 in pseudo-rapidity |η|<0.5. The transverse momentum pT of charged particles is measured down to 0.15 GeV/c which gives access to the low pT fragments of the jet. Jets found in heavy-ion collisions are corrected event-by-event for average background density and on an inclusive basis (via unfolding) for residual background fluctuations and detector effects. A strong suppression of jet production in central events with respect to peripheral events is observed. The suppression is found to be similar to the suppression of charged hadrons, which suggests that substantial energy is radiated at angles larger than the jet resolution parameter R=0.3 considered in the analysis. The fragmentation bias introduced by selecting jets with a high pT leading particle, which rejects jets with a soft fragmentation pattern, has a similar effect on the jet yield for central and peripheral events. The ratio of jet spectra with R=0.2 and R=0.3 is found to be similar in Pb-Pb and simulated PYTHIA pp events, indicating no strong broadening of the radial jet structure in the reconstructed jets with R<0.3.
The transverse momentum (pT) spectrum and nuclear modification factor (RAA) of reconstructed jets in 0–10% and 10–30% central Pb–Pb collisions at √sNN = 2.76 TeV were measured. Jets were reconstructed using the anti-kT jet algorithm with a resolution parameter of R = 0.2 from charged and neutral particles, utilizing the ALICE tracking detectors and Electromagnetic Calorimeter (EMCal). The jet pT spectra are reported in the pseudorapidity interval of |ηjet| < 0.5 for 40 < pT, jet < 120 GeV/c in 0–10% and for 30 < pT, jet < 100 GeV/c in 10–30% collisions. Reconstructed jets were required to contain a leading charged particle with pT > 5 GeV/c to suppress jets constructed from the combinatorial background in Pb–Pb collisions. The leading charged particle requirement applied to jet spectra both in pp and Pb–Pb collisions had a negligible effect on the RAA. The nuclear modification factor RAA was found to be 0.28 ± 0.04 in 0–10% and 0.35 ± 0.04 in 10–30% collisions, independent of pT, jet within the uncertainties of the measurement. The observed suppression is in fair agreement with expectations from two model calculations with different approaches to jet quenching.