Manuel Fiolhais

Centre for Computational Physics(CFC-UC)

University of Coimbra, Portugal

Some highlights of Some highlights of Nuclear Physics atNuclear Physics atThe University of CoimbraThe University of Coimbra

NuPECC meeting, Lisboa, November 2004

Department of PhysicsDepartment of Physics

~ 55 staff members~ 55 staff members

~ 10 are nuclear & hadron physicists~ 10 are nuclear & hadron physicists

Other areas: condensed matter (clusters, X-ray diffraction), high energy, cosmology, instrumentation, electronics, education, etc.

Research activity organized in5 Research Centres

Centre for Computational Physics (~25% nuclear physics)

Centre for Theoretical Physics (~50% nuclear physics)

Lab for advanced computing of CFC

100 processors interconnected

“Centopeia”(centipede)

•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

Publications in international journals

Some keywords (not exhaustive)

• Nuclear Physics at Intermediate energies

• Effective models of QCD

• Chiral symmetry

• Phenomenology of the nucleon and isobars

• Relativistic Nuclear Physics

• Astrophysics

• Meson spectroscopy

The Ds (2117) meson in a unitarized quark model

 

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 2.317 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 2.1-2.3 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, +351-21-841-9103)  

1996

1997

1998

1999

2000

2001

2002

2003

2004

Eef van Beveren

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.

(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

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 conservationEOS in hadronic matter, with chiral symmetry.Collective modes in relativistic matter for asymmetric matter

- relativistic Vlasov equationAsymmetric 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 matterHartree-Fock with correlations (unitary operator)

Algebraic models

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

q q

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 propertiese

N*

e'

N

Nucleon properties and NN* transitions

MF et al.

- Application of quark models to the EOS quark matter

and study of compact objects (hybrid stars, quark

stars)

Astroparticle physics

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 J1856.5-3754 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 J1856.5-3754

Chandra X-ray image

MF et al.

• 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.

Programmed activities

Collaborations abroad

• Bochum (Germany)

• Ljubljana (Slovenia)

• Rio de Janeiro, S. Paulo, Florianópolis, Belo Horizonte (Brazil)

•Cracow (Poland)

• JINR, Dubna (Russia)