exotic nuclei structure and reaction noyaux exotiques ... - IPN - IN2P3

More documents

Recommendations

Info

Constraining pairing interactions with pairing vibrations IPNO Participation: M. Grasso, E. Khan, J. Margueron Des interactions d’appariement avec différentes dépendances en densité (surface, melange surfacevolume) sont contraintes avec les energies de séparations à deux neutrons dans la chaine isotopique des étains. La réponse associée aux vibrations de paires dans les noyaux très riches en neutrons est sensible à la dépendence en densité de l’interaction d’appariement. En utilisant la meme interaction d’appariement dans la matière nucléaire que dans les isotopes d’étains, la région optimale en densité pertinente pour le canal de d’appariement est étudiee. The impact of various pairing interactions on pairing vibrations predictions has been analysed for the first time using a HFB+QRPA approach. They should provide a good sensitivity from a pure surface interaction compared to mixed interactions, especially in the case of very neutron-rich nuclei such as 136 Sn. Moreover nuclear matter gap calculations show that the low density range is sensitive to the surface/volume character of the pairing interaction. In the case of exotic nuclei, pairing vibrations are also found more sensitive to the surface/ volume type of the pairing interaction than in the case of stable nuclei. This may be due to the larger extension of the neutron density in very neutronrich nuclei . The same study using an isospin dependent pairing interaction will be undertaken. The hope is to come one step closer to a more global pairing interaction, using odd even mass staggering, pairing vibrations, and nuclear matter as constraints. Experimentally, the pairing transition densities can be tested through the form factor used to calculate the two neutrons transfer cross section. This implies to use a adequate reaction model. Work along these lines will be undertaken in an near future. The figure show the transition densities of a pairing vibration in 136 Sn They exhibit very different shapes, comparing results with the pure surface pairing interaction and the mixed pairing interaction. Hence 136 Sn is a good test case to probe the pairing interaction through pairing vibrations. For instance in the case of the most intense peak, the central part is dominant in the transition density for the mixed case, whereas the surface part of the transition density dominates in the pure surface interaction. Hence a measurement of the angular distributions associated with the pairing vibration strength in very neutron rich-nuclei such as 136 Sn seems more decisive to disentangle between the pairing interactions than with 124 Sn. This may be due to the larger neutron skin in 136 Sn, consisting of low density neutron-rich matter. It has been shown in a previous work how the pairing transition densities allow to calculate the two neutron form factor in order to predict angular distributions for pairing vibrations. Work along these lines should be undertaken in order to bring additional constrains on the pairing interaction. References: E. Khan, M. Grasso, J. Margueron, Phys. Rev. C80, 044328 (2009) 65
Pairing and nuclear incompressibility IPNO Participation: E. Khan Les noyaux sont des sondes adaptées pour étudier le rôle de la superfluidité dans la compressibilité des systèmes fermioniques. Le centroide de la résonance géante monopolaire (GMR) dans les isotopes d’étain est prédite en utilisant une approche contrainte Hartree-Fock Bogoliubov (CHFB), ce qui assure une autoconsistance exacte. La superfluidité favorise la compressibilité des noyaux. Les correlations d’appariement expliquent pourquoi les noyaux doublement magiques comme le 208 Pb sont plus durs à comprimer que des noyaux à couches ouvertes. La dépendance de l’incompressibilite de la matiere nucléaire, en fonction de l’appariement devrait être étudiée. Superfluidity favours the compressibility of nuclei, using a fully microscopic CHFB approach on the Tin isotopic chain. This may be the first evidence of a sizable effect of superfludity on the compressibility of a Fermionic system. Pairing effects should be described using a full microscopic HFB treatment. Doubly magic nuclei exhibit a specific increase of the GMR energy, due to the collapse of pairing. 208 Pb is therefore the "anomalous" data compared to the others. It is not possible to disentangle pairing interaction from the equation of state when providing the nuclear matter value of incompressibility. Indeed the pairing gap dependence on the nuclear matter incompressibility should be investigated, since it is shown that incompressibility decreases with increasing pairing gap in nuclei. Additional theoretical investigations are called for in order to predict the GMR including the mutually enhancement magicity effect. The macroscopic extraction of K Sym may be ill-defined and should be extended to include pairing effects. Experimentally, measurements of the GMR in unstable nuclei should be performed in doubly magic 132 Sn, as well as extending the measurement on the Sn and Pb isotopic chains. References: E. Khan Phys. Rev. C80, 057302 (2009) E. Khan Phys. Rev. C80, 011307R (2009) To further investigate the role of pairing on nuclear incompressibility, the figure displays the incompresiibility in Tin isotopes with respect to the average pairing gap calculated using the HFB approach, from 112 Sn to 132 Sn. A clear correlation is observed: the more superfluid the nuclei, the lower the incompressibility. Hence it may be easier to compress superfluid nuclei. This may be the first evidence of the role of superfluidity on the compressibility of a Fermionic system. A possible interpretation is that Cooper pairs can modify bulk properties, as known from nuclear physics phenomenology 66
Page 1 and 2:
EXOTIC NUCLEI STRUCTURE AND REACTIO
Page 3 and 4:
in the spectra by analyzing their t
Page 5 and 6: were taken from ref. [5]. Concernin
Page 7 and 8: keV -ray with the particles and the
Page 9 and 10: the 605.9 keV line of the 74 Zn 2+
Page 11 and 12: Figure 2 a n d analysis. Figure 2 s
Page 13 and 14: ing particles was thus obtained by
Page 15 and 16: First p-p p collisions in the ALICE
Page 17 and 18: Quarkonia physics with ALICE IPNO P
Page 19 and 20: NA50 updated puzzle IPNO Participat
Page 21 and 22: Status of the HADES experiment (I):
Page 23 and 24: Status of the HADES experiments (II
Page 25 and 26: Status of the HADES experiment (III
Page 27 and 28: Hadron physics in pbar-p p annihila
Page 29 and 30: Hadron Electrodynamics IPNO Partici
Page 31 and 32: G0 experiment at Jefferson Lab. IPN
Page 33 and 34: GEp-III and GEp-2 at Jefferson Lab
Page 35 and 36: Exotic low mass narrow baryons from
Page 37 and 38: The PVA4 parity violation experimen
Page 39 and 40: Etude des Distributions de Partons
Page 41 and 42: Latest Results from GRAAL IPNO Part
Page 43 and 44: Persistence of the Polarization in
Page 45 and 46: The northern site of the Pierre Aug
Page 47 and 48: The Pierre Auger southern Observato
Page 49 and 50: In figure 4 we plot the differentia
Page 51 and 52: THEORETICAL PHYSICS Research in the
Page 53 and 54: transfer reaction, the 34 Si(d, 3 H
Page 55: Collective excitations with SKYRME
Page 59 and 60: Pairing properties in nuclei and in
Page 61 and 62: Evaporation-residue residue cross s
Page 63 and 64: Extending the VMI model: normal and
Page 65 and 66: Alpha particle condensation in nucl
Page 67 and 68: Collective Modes in Ultracold Trapp
Page 69 and 70: Exploring key unknown neutrino prop
Page 71 and 72: Relic astrophysical and cosmologica
Page 73 and 74: After a term by term Borel resummat
Page 75 and 76: Chiral expansions of the π 0 lifet
Page 77 and 78: IPNO Participation: H. Sazdjian Eff
Page 79 and 80: fer is used to extract f + (0). We
Page 81 and 82: cleon. The spectrum becomes strongl
Page 83 and 84: A pseudo Coulombian potential in D=
Page 85 and 86: The many-body problem with an energ
Page 87 and 88: The rotational spectrum and the att
Page 89 and 90: Z-identification of very heavy nucl
Page 91 and 92: The Pegase project, a new solid sur
Page 93 and 94: But at 80 keV total energy ( 200 eV
Page 95 and 96: Isospin effects on fragment and par
Page 97 and 98: Radial collective energy and fragme
Page 99 and 100: Latent heat of the phase transition
Page 101 and 102: Alpha-particle particle condensatio
Page 103 and 104: Fluo X: Deexcitation time measureme
Page 105 and 106: ENERGY AND ENVIRONMENT The increasi
Page 107 and 108:
toe/cap/y which energy access inequ
Page 109 and 110:
nides. A global comparison can be p
Page 111 and 112:
3D coupling of Monte-Carlo neutroni
Page 113 and 114:
Fission cross sections of actinides
Page 115 and 116:
Studies and synthesis of specific m
Page 117 and 118:
Chemistry and Electrochemistry of T
Page 119 and 120:
function of temperature. The recent
Page 121 and 122:
global electron number of the redox
Page 123:
(D 0 /D)-1 ln complexes of Pa(V). I
show all

exotic nuclei structure and reaction noyaux exotiques ... - IPN - IN2P3

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?