An Evolutionary Study of Carex Subg. Psyllophorae (Cyperaceae) Sheds Light on a Strikingly Disjunct Distribution in the Southern Hemisphere, With Emphasis on Its Patagonian Diversification

Carex subgenus Psyllophorae is an engaging study group due to its early diversification compared to most Carex lineages, and its remarkable disjunct distribution in four continents corresponding to three independent sections: sect. Psyllophorae in Western Palearctic, sect. Schoenoxiphium in Afrotropical region, and sect. Junciformes in South America (SA) and SW Pacific. The latter section is mainly distributed in Patagonia and the Andes, where it is one of the few Carex groups with a significant in situ diversification. We assess the role of historical geo-climatic events in the evolutionary history of the group, particularly intercontinental colonization events and diversification processes, with an emphasis on SA. We performed an integrative study using phylogenetic (four DNA regions), divergence times, diversification rates, biogeographic reconstruction, and bioclimatic niche evolution analyses. The crown age of subg. Psyllophorae (early Miocene) supports this lineage as one of the oldest within Carex. The diversification rate probably decreased over time in the whole subgenus. Geography seems to have played a primary role in the diversification of subg. Psyllophorae. Inferred divergence times imply a diversification scenario away from primary Gondwanan vicariance hypotheses and suggest long-distance dispersal-mediated allopatric diversification. Section Junciformes remained in Northern Patagonia since its divergence until Plio-Pleistocene glaciations. Andean orogeny appears to have acted as a northward corridor, which contrasts with the general pattern of North-to-South migration for temperate-adapted organisms. A striking niche conservatism characterizes the evolution of this section. Colonization of the SW Pacific took place on a single long-distance dispersal event from SA. The little ecological changes involved in the trans-Pacific disjunction imply the preadaptation of the group prior to the colonization of the SW Pacific. The high species number of the section results from simple accumulation of morphological changes (disparification), rather than shifts in ecological niche related to increased diversification rates (radiation).Fil: Benítez Benítez, Carmen. Universidad Pablo de Olavide; EspañaFil: Otero, Ana. Field Museum of Natural History; Estados UnidosFil: Ford, Kerry A.. Manaaki-Whenua Landcare Research; Nueva ZelandaFil: García Moro, Pablo. Universidad Autónoma de Madrid; EspañaFil: Donadío, Sabina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Luceño, Modesto. Universidad Pablo de Olavide; EspañaFil: Martín Bravo, Santiago. Universidad Pablo de Olavide; EspañaFil: Jiménez-Mejías, Pedro. Universidad Autónoma de Madrid; Españ

Simultaneous analysis of elastic, breakup, and fusion channels for 6He induced reactions at energies near the coulomb barrier

5th International Conference FUSION11We present some recent applications of the Continuum-Discretized Coupled-Channels (CDCC) and Coupled-Reaction-Channels (CRC) methods to the study of reactions induced by weakly-bound nuclei on stable targets. The methods are applied to the scattering of the Borromean nucleus 6He at energies around the Coulomb barrier. Elastic scattering data are very well described by four-body CDCC calculations (based on a three-body description of the 6He nucleus) but also by simpler three-body CDCC calculations, using a suitable two-body model for 6He. By contrast, inclusive α data are better described using the CRC approach, which treats the breakup within the transfer to the continuum picture and, unlike the CDCC method, allows the inclusion of transfer to bound states of the target. We explore also the possibility of calculating the fusion cross sections using the CRC frameworkMinisterio de Ciencia e Innovación FPA2009-0765

The 6He Optical Potential at energies around the Coulomb barrier

We present an Optical Model (OM) study of 6He on 208Pb elastic scattering data, measured at laboratory energies around the Coulomb barrier (Elab=14, 16, 18, 22, and 27 MeV) [1]. For the projectile-target bare interaction, we use the microscopic São Paulo Potential (SPP). This bare interaction is supplemented with a Coulomb Dipole Polarization (CDP) potential, as well as a diffuse complex Woods-Saxon potential. Four-body Continuum-Discretized-Coupled-Channels (CDCC) calculations have been performed in order to support the optical model analysis. We have also studied the α channel, which is the dominant reaction process. In the analysis of this channel, we compare the angular and energy distributions of the α particles measured at 22 MeV, with Distorted Wave Born Approximation (DWBA) calculations

Effects of coupling to breakup channels in reactions induced by weakly bound and halo nuclei

12th International Conference on Nucleus-Nucleus Collisions 2015The experimental elastic scattering angular distributions of the collisions involving the weakly bound nuclei 6,7Li and the halo nucleus 6He on the same 64Zn target at several energies around the Coulomb barrier were measured at the Laboratori Nazionali del Sud (LNS, Italy), and the Cyclotron Research Center, Louvain La Neuve (Belgium), respectively. The experimental elastic scattering angular distributions of the 6,7Li + 64Zn systems have been analyzed within the continuumdiscretized coupled-channels method, while the 6He + 64Zn data have been compared with both continuum-discretized coupled-channels and coupled-reaction-channels calculation

Comparison of the effects of couplings to breakup channels in reactions induced by 6Li and 6He on the same 64Zn target

The experimental elastic scattering angular distributions for the weakly bound nuclei 6,7Li and for the halo nucleus 6He on the same 64Zn target at several energies around the Coulomb barrier were measured at the Laboratori Nazionali del Sud (LNS, Italy) and at the Cyclotron Research Center, Louvain La Neuve (Belgium), respectively. The measured elastic scattering angular distributions of these three systems at the same center of mass energy have been compared. The experimental data of the 6,7Li+ 64Zn systems have been analyzed within the CDCC method, while the 6He+64Zn data have been compared with both both CDCC and CRC calculations

Effects of coupling to breakup in the 6,7 Li + 64 Zn systems at near-barrier energies

Elastic scattering angular distributions for the weakly bound nucleus Li7 on Zn64 have been measured in a wide angular range at energies around the Coulomb barrier. The present experimental data and our previously measured elastic scattering data for the system Li6+Zn64 have been analyzed within the continuum-discretized coupled-channels method, where the resonant and nonresonant states of the projectile are taken into account. In this theoretical framework, we have also analyzed our previously measured excitation functions of elastic scattering at backward angles and the corresponding barrier distributions for the same systems. A good agreement between the experimental data and the calculations has been observed. The obtained results, besides confirming the importance of the coupling to the breakup channels in collisions with weakly bound nuclei, show that, in the case of Li6, the inclusion of the resonant states of the projectile produces non-negligible effects.Ministerio de Economía y Competitividad (España) FIS2013-41994-PJunta de Andalucía FQM160 P07-FQM-02894Programa Consolider-Ingenio 2010 (España) CSD2007-0004

Interaction of 8 He with 208Pb at near-barrier energies: 4 He and 6 He production

Spanish Ministry of Economy and Competitiveness-FPA-2010-22131-CO2-01 (FINURA) y FPA2013-47327-C2-1-RMinistry of Science and Higher Education of Poland-N202 033637National Science Centre of Poland-2013/08/M/ST2/00257 (LEA-COPIGAL) y 2014/14/M/ST2/00738 (COPIN-INFN Collaboration)European Science Foundation-EUI2009-04163432 (EUROGENESIS

Coupling to continuum effects in the 6,7Li +64Zn reactions at energies around the Coulomb barrier

The elastic scattering angular distributions for the weakly bound nuclei 6Li and 7Li on 64Zn were measured in a wide angular range at energies around the Coulomb barrier. In addition, the excitation functions of quasi-elastic scattering at backward angles were measured and the corresponding barrier distributions were derived. The experimental data were analysed within the continuum-discretized-coupled-channel method. In this contribution, we will present a detailed study concerning the effects of the break-up channels in the 6,7Li +64 Zn reactions

Probing proton halo effects in the 8B+64Zn collision around the Coulomb barrier

Proton halo effects in the 8B+64Zn reaction at an energy around 1.5 times the Coulomb barrier have been studied at HIE-ISOLDE CERN using, for the first time, the only existing postaccelerated 8B beam. This, together with the use of a high granularity and large solid angle detection system, allowed for a careful mapping of the elastic angular distribution, especially in the Coulomb-nuclear interference region. Contrary to what is observed for the one-neutron halo nucleus 11Be on the same target in a similar energy range, the analysis of the elastic scattering angular distribution shows only a modest suppression of the Coulomb-nuclear interference peak, with no remarkable enhancement of the total reaction cross-section. Inclusive angular and energy distributions of 7Be produced in direct reaction processes have also been measured. The comparison of these data with the results of theoretical calculations for the elastic and non-elastic breakup contributions indicate that both processes are important. Overall, the experimental data suggest a 8B collision dynamics at the barrier very different from the one of neutron halo nuclei, showing only modest effects of coupling to continuum. This behaviour can be interpreted as due to the presence of the additional Coulomb interactions halo-core and halo-target together with the presence of the centrifugal barrier felt by the valence proton of 8B.UE ENSAR2 Subvención nº 654002Istituto Nazionale di Fisica Nucleare (INFN) Italia, Science and Technology Facilities Council (STFC) Reino Unido y la Agencia Española de Financiación “ELEGANT” PGC2018-095640-B-100, FIS2017-88410-P, PDI2019- 104390GB-100, FPA2016-77689-C2-1-R, PGC2018-096994-B-C21, PGC2018-096994-B-C22 y RTI2018-098868-B-I0

11Li Breakup on 208Pb at Energies Around the Coulomb Barrier

The inclusive breakup for the 11Li+208Pb reaction at energies around the Coulomb barrier has been measured for the first time. A sizable yield of 9Li following the 11Li dissociation has been observed, even at energies well below the Coulomb barrier. Using the first-order semiclassical perturbation theory of Coulomb excitation it is shown that the breakup probability data measured at small angles can be used to extract effective breakup energy as well as the slope of B(E1) distribution close to the threshold. Four-body continuum-discretized coupled-channels calculations, including both nuclear and Coulomb couplings between the target and projectile to all orders, reproduce the measured inclusive breakup cross sections and support the presence of a dipole resonance in the 11Li continuum at low excitation energy.Consolider Ingenio 2010 Program CPAN CSD2007- 00042Proyectos Nacionales Españoles FPA2009-08848 FPA2009-07387 FPA2010-22131-C02-01 FPA2009-076