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The University of Coimbra

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1 The University of Coimbra
Some highlights of Nuclear Physics at The University of Coimbra Manuel Fiolhais Centre for Computational Physics (CFC-UC) University of Coimbra, Portugal NuPECC meeting, Lisboa, November 2004

2 Department of Physics ~ 55 staff members ~ 10 are nuclear & hadron physicists Other areas: condensed matter (clusters, X-ray diffraction), high energy, cosmology, instrumentation, electronics, education, etc.

3 Centre for Computational Physics
Research activity organized in 5 Research Centres Centre for Computational Physics (~25% nuclear physics) Centre for Theoretical Physics (~50% nuclear physics)

4 Lab for advanced computing of CFC
100 processors interconnected “Centopeia” (centipede)

5 Publications in international journals
Physical Review C Physical Review D Physical Review Letters Physics Letters B Nuclear Physics A Nuclear Physics B European Physics Journal Europhysics Letters Journal of Physics G: Particle and Nuclear Physics

6 Some keywords (not exhaustive)
Relativistic Nuclear Physics Nuclear Physics at Intermediate energies Effective models of QCD Chiral symmetry Phenomenology of the nucleon and isobars Meson spectroscopy Astrophysics

7 The Ds (2117) meson in a unitarized quark model
Eef van Beveren Number 643 #1, June 26, 2003 by Phil Schewe, James Riordon, and Ben Stein The Meson Ds(2317) The meson Ds(2317), discovered a couple of months ago in high energy electron-positron collisions at SLAC, possesses a mass of GeV, some 170 MeV lighter than expected, at least according to prevalent theories of quark interactions. Hence physicists need a new explanation of how a charm quark attached to an antistrange quark should have this particular mass. In general, Ds and D mesons are a class of particles, each consisting of a charm quark attached to a light antiquark. (The subscript "s" pertains to all those D's containing a strange antiquark; "ordinary" D mesons consist of a charm quark and a down antiquark.) The Babar detection group at SLAC responsible for the experimental discovery (Aubert et al., Physical Review Letters, 20 June 2003; also see press release) suggests that the Ds(2317) might be a novel particle made of 4 quarks. But a pair of physicists in Portugal claim that in their model, assuming that the meson is indeed a charm/antistrange combination, the mass comes out in the right range if the strong-nuclear-force interactions responsible for the creation and annihilation of extra quark-antiquark pairs are taken into account. Using this model, Eef van Beveren (University of Coimbra) and George Rupp (CFIF Lab, IST, Lisbon) have successfully predicted meson masses in the past (such as the kappa meson, discovered at Fermilab (E791) at a mass of 800 MeV), while in the case of Ds mesons they predict a mass very near the Ds(2317) found already, and another at about 2.9 GeV (yet to be found). As to D mesons, they predict the equivalent of the Ds(2317) at a mass range of GeV (for which preliminary evidence exists), and a heavier one at about 2.8 GeV (still undetected). According to van Beveren and Rupp, both pairs of Ds and D mesons are, in some sense, different aspects of the same underlying quark-antiquark state. (Physical Review Letters, upcoming article, see website or contact George Rupp, ) 1996 1997 1998 1999 2000 2001 2002 2003 2004

8 Chiral gauge theories and heavy-ions
Brigitte Hiller and Alex Blin Dynamics of chiral gauge theories in a generalized Schwinger-DeWitt approach: generalization to arbitrary non-degenerate mass matrices. Calculation of the low lying spectrum of pseudoscalars Calculation of the low lying spectrum of scalars Calculation of pion-kaon scattering lengths Description of resonance production in ultra-relativistic heavy-ion reactions. Invariant mass spectra of various channels Ratios of resonances Abundances and transverse momentum spectra Correlations in the invariant mass of decay products.

9 (3-flavour) Nambu-Jona Lasínio model
Maria da Conceição Ruivo Phase transitions, restoration of symmetries and meson properties at finite temperature and density - Phase transitions in hot and dense matter - Pseudoscalar meson properties (masses and quark meson coupling constants) - Two photon decays of the neutral mesons 0 and  in vacuum and in medium - Effective restoration of chiral and UA(1) symmetry at finite temperature and density

10 EoS and relativistic nuclear matter
Constança Providência EOS for stellar matter: - hadronic matter: non-linear Walecka model (NLWM) with hyperons, quark meson coupling model (QMC) with hyperons and kaon condensate, NLWM with  meson - quark matter: su(3) NJL model and MIT Bag model in the normal phase and CFL phase - mixed phase: global charge conservation EOS in hadronic matter, with chiral symmetry. Collective modes in relativistic matter for asymmetric matter - relativistic Vlasov equation Asymmetric matter liquid-gas phase transition in relativistic models - relativistic mean field - NLWM, NLWM with density dependent coupling constants, NLWM with  meson, QMC -spinodal, direction of instability, effect of Coulomb interaction Correlations in relativistic models: EOS for nuclear matter Hartree-Fock with correlations (unitary operator) Algebraic models

11 Pseudospin symmetry in nuclei
Pedro Alberto, MF Pseudospin symmetry as a dynamical symmetry in nuclei Dependence with potential parameters (radius, thickness,depth) Coulomb effects Degeneracy between single-particle states

12 Nucleon and isobar description:
Nucleon properties and NN* transitions MF et al. The nucleon as a chiral soliton Linear sigma model Chromodielectric model Chiral-quark-soliton model (NJL inspired) Bag models (CBM, etc.) Nucleon and isobar description: Electromagnetic properties Axial properties Strong properties

13 Astroparticle physics
MF et al. - Application of quark models to the EOS quark matter and study of compact objects (hybrid stars, quark stars) From NASA press release 02-65, April 10th 2002: “NASA's Chandra X-ray Observatory has found two stars - one too small, one too cold - that reveal cracks in our understanding of the structure of matter. These discoveries open a new window on nuclear physics, offering a link between the vast cosmos and its tiniest constituents. Chandra's observations of RX J and 3C58 suggest that the matter in these stars is even denser than nuclear matter found on Earth. This raises the possibility these stars are composed of pure quarks…” RX J Chandra X-ray image

14 Programmed activities
Axial form factors of N- Electromagnetic NN* transitions Structure functions Quark distributions Medium effects in the nucleon Studies of pseudo-spin symmetries in nuclei Etc.

15 Collaborations abroad
Bochum (Germany) Ljubljana (Slovenia) Rio de Janeiro, S. Paulo, Florianópolis, Belo Horizonte (Brazil) Cracow (Poland) JINR, Dubna (Russia)


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