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SU(3) Clebsch-Gordan coefficients at large $N_c$ Stancu, Floarea in Nuclear Physics A (2016), 945 It is argued that several papers where SU(3) Clebsch-Gordan coefficients were calculated in order to describe properties of hadronic systems are, up to a phase convention, particular cases of analytic ... [more ▼] It is argued that several papers where SU(3) Clebsch-Gordan coefficients were calculated in order to describe properties of hadronic systems are, up to a phase convention, particular cases of analytic formulae derived by Hecht in 1965 in the context of nuclear physics. This is valid for irreducible representations with multiplicity one in the corresponding Clebsch-Gordan series. For multiplicity two, Hecht has proposed an alternative which can provide correct $1/N_c$ sub-leading orders in large $N_c$ studies. [less ▲] Detailed reference viewed: 25 (4 ULg)Gauge symmetry and background independence: Should the proton spin decomposition be path independent? Lorce, Cédric in Nuclear Physics A (2014) Detailed reference viewed: 17 (2 ULg)Extension of the Liège intranuclear cascade model at incident energies between 2 and 12 GeV. Aspects of pion production. ; Cugnon, Joseph in Nuclear Physics A (2011), 866 Detailed reference viewed: 13 (1 ULg)Quark transverse charge densities in the Delta(1232) from lattice QCD ; ; et al in Nuclear Physics A (2009), A825 We extend the formalism relating electromagnetic form factors to transverse quark charge densities in the light-front frame to the case of a spin-3/2 baryon and calculate these transverse densities for ... [more ▼] We extend the formalism relating electromagnetic form factors to transverse quark charge densities in the light-front frame to the case of a spin-3/2 baryon and calculate these transverse densities for the $\Delta (1232)$ isobar using lattice QCD. The transverse charge densities for a transversely polarized spin-3/2 particle are characterized by monopole, dipole, quadrupole, and octupole patterns representing the structure beyond that of a pure point-like spin-3/2 particle.We present lattice QCD results for the $\Delta$-isobar electromagnetic form factors for pion masses down to approximatively 350 MeV for three cases: quenched QCD, two-degenerate flavors of dynamicalWilson quarks, and three flavors of quarks using a mixed action that combines domain wall valence quarks and dynamical staggered sea quarks. We extract transverse quark charge densities from these lattice results and find that the $Delta$ is prolately deformed, as indicated by the fact that the quadrupole moment $G_{E2}(0)$ is larger than the value −3 characterizing a point particle and the fact that the transverse charge density in a $\Delta^+$ of maximal transverse spin projection is elongated along the axis of the spin. [less ▲] Detailed reference viewed: 22 (5 ULg)A Review of the hard pomeron in soft diffraction Cudell, Jean-René ; ; et al in Nuclear Physics A (2005), 755 We review the evidence for the presence of a hard singularity in soft forward amplitudes, and give an estimate of its trajectory and couplings. Detailed reference viewed: 52 (11 ULg)Three-body confinement force in a realistic constituent quark model ; Stancu, Floarea in Nuclear Physics A (2003), 726(3-4), 327-338 We show that in realistic constituent quark models based on a two-body confinement interaction color states appear in the middle of the experimentally known spectrum. To avoid this situation we implement ... [more ▼] We show that in realistic constituent quark models based on a two-body confinement interaction color states appear in the middle of the experimentally known spectrum. To avoid this situation we implement a three-body confinement interaction, introduced on an algebraic basis, into a semi relativistic version of the Goldstone boson exchange constituent quark model and by solving the Faddeev equations we show that this interaction can increase the gap between singlet and color states, such as the latter can be ignored and the known baryons can be described as simple q(3) systems. We analyze the effect of a Delta- and a Y-shape three-body interaction. (C) 2003 Elsevier B.V. All rights reserved. [less ▲] Detailed reference viewed: 14 (1 ULg)Nucleon nucleon interaction in a chiral constituent quark model Bartz, Daniel ; Stancu, Floarea in Nuclear Physics A (2002), A699(1-2), 316-319 We study the nucleon-nucleon interaction within a chiral constituent quark model where the hyperfine interaction is due to pseudoscalar meson exchange. We calculate the S-3(1) and S-1(0) phase shifts by ... [more ▼] We study the nucleon-nucleon interaction within a chiral constituent quark model where the hyperfine interaction is due to pseudoscalar meson exchange. We calculate the S-3(1) and S-1(0) phase shifts by using the resonating group method. Their behaviour clearly indicates the presence of a strong repulsive core at short distance. This is due to the spin-flavour symmetry of the interaction and to the quark interchange between the two interacting nucleons. We add a sigma-meson exchange quark-quark interaction which provides a medium range attraction necessary to describe the S-1(0) phase shift. We also explore the role of a tensor interaction at the quark level. [less ▲] Detailed reference viewed: 20 (5 ULg)Stability of strange quark matter in an effective chiral model with scale anomaly Jaminon, Martine ; in Nuclear Physics A (2001), 686 Stability of strange quark matter is investigated within a chiral model which implements the scale anomaly of QCD. As far as quark confinement is mimicked by a large value of the u-quark mass, the model ... [more ▼] Stability of strange quark matter is investigated within a chiral model which implements the scale anomaly of QCD. As far as quark confinement is mimicked by a large value of the u-quark mass, the model behaves in the chiral limit as a MIT bag model: it yields a stable system composed of quarks surrounded by the vacuum. As soon as finite current quark masses are taken into account, stability is however lost. [less ▲] Detailed reference viewed: 17 (2 ULg)N N scattering phase shifts in a chiral constituent quark model Bartz, Daniel ; Stancu, Floarea in Nuclear Physics A (2001), A688 We study the nucleon-nucleon interaction within a chiral constituent quark model which reproduces succesfully the baryon spectra. We calculate the $^3S_1$ and $^1S_0$ phase shifts by using the resonating ... [more ▼] We study the nucleon-nucleon interaction within a chiral constituent quark model which reproduces succesfully the baryon spectra. We calculate the $^3S_1$ and $^1S_0$ phase shifts by using the resonating group method. They clearly indicate the presence of a strong repulsive interaction at short distance, due to the spin-flavour symmetry of the quark-quark interaction and of the quark interchange between the two interacting nucleons. A $\sigma$-meson exchange quark-quark interaction, providing a medium-range attraction, helps to get closer to the experimental phase shifts. [less ▲] Detailed reference viewed: 13 (1 ULg)The short-range baryon baryon interaction in a chiral constituent quark model Stancu, Floarea ; in Nuclear Physics A (2001), A683 The previous analysis of the short-range $NN$ repulsion originating from the Goldstone boson exchange hyperfine interaction between constituent quarks is revisited. We study in which respects the ... [more ▼] The previous analysis of the short-range $NN$ repulsion originating from the Goldstone boson exchange hyperfine interaction between constituent quarks is revisited. We study in which respects the repulsion depends on the radial form of the spin-spin quark-quark force. We show that while the radial form affects the structure of the 6Q wave function, the short-range repulsion in the $NN$ system persists in any case. We extend our analysis to other $YN$ and $YY$ (flavor octet-octet) systems and demonstrate that the flavor-spin hyperfine interaction implies a short-range repulsion in these B=2 systems as well. [less ▲] Detailed reference viewed: 18 (3 ULg)Strong decays of the glueball in a scaled effective Lagrangian Jaminon, Martine ; Mathot, Michel ; in Nuclear Physics A (2000), 662 We calculate the scalar glueball decays into pipi, etaeta, etaeta' and KK within a modified version of the NJL model which implements the QCD trace anomaly. The glueball is assumed to be the f0(1500). It ... [more ▼] We calculate the scalar glueball decays into pipi, etaeta, etaeta' and KK within a modified version of the NJL model which implements the QCD trace anomaly. The glueball is assumed to be the f0(1500). It is coupled to the quarks due to its mixing with the scalar isoscalar mesons. The decay widths then contain a contribution coming from the triangle Feynman diagram. Moreover, they contain two additional contributions corresponding to the local decay of the glue component of the f0(1500): one comes from the process of regularization of the quark loop, the other from the interaction term a2chi2phgr2. Except for the etaeta' case, this local decay reduces the value of the width. The axial anomaly is introduced via a mass term for the eta'. As far as the lightest scalar glueball is identified with the f0(1500), the model cannot reproduce at the same time the dynamical properties of scalars and pseudoscalars. Since we do not include a model of confinement, we need to use a large quark mass (725 MeV) in our calculations. This leads to unphysical results for the two-pion decay width. A definitive test of our model awaits the introduction of a model of confinement, which we hope to include in a future work. [less ▲] Detailed reference viewed: 26 (3 ULg)Two photon decay of the glueball and scalar isosclar mesons in a scaled NJL model Jaminon, Martine ; in Nuclear Physics A (1998), 636 We use a modified version of the Nambu-Jona-Lasinio (NJL) model which implements the QCD trace anomaly to calculate the two photon decay width of the glueball (f0(1500)) and of the two scalar mesons (f0 ... [more ▼] We use a modified version of the Nambu-Jona-Lasinio (NJL) model which implements the QCD trace anomaly to calculate the two photon decay width of the glueball (f0(1500)) and of the two scalar mesons (f0(1370), fJ=0(1710)) to which it is mixed. We investigate the effect of the mixing over the coupling constants of the f0 states to the quarks and over the widths. We show that mass and phase space effects are crucial, at least in the NJL model, in determining the relative strength of the 2γ widths. [less ▲] Detailed reference viewed: 16 (1 ULg)Gluonic content of the scalar meson nonet in a scaled effective Lagrangian Jaminon, Martine ; in Nuclear Physics A (1997), 619 A scaled SU(3) Nambu-Jona-Lasinio Lagrangian is used to compute the mass of the nine scalar mesons in the vacuum and the mass of the glueball. This chiral model provides a gluonic content to the scalar ... [more ▼] A scaled SU(3) Nambu-Jona-Lasinio Lagrangian is used to compute the mass of the nine scalar mesons in the vacuum and the mass of the glueball. This chiral model provides a gluonic content to the scalar mesons as well as a quark content to the glueball. It is shown that a suitable choice of the vacuum gluon condensate allows reproduction of the experimental masses of the scalar mesons except for K*0(1430). This choice corresponds to a weak coupling between the gluon and quark condensates, giving f0(1500) or fJ(1710) which is nearly a pure glueball. [less ▲] Detailed reference viewed: 11 (1 ULg)Phase transition and thermodynamics of a hot and dense system in a scaled NJL model Cugnon, Joseph ; Jaminon, Martine ; in Nuclear Physics A (1996), 598 he chiral phase transition of a hot and dense system of quarks is studied within a modified SU(3) NJL Lagrangian that implements the QCD scale anomaly. The u- and s-quark condensates can or can not feel ... [more ▼] he chiral phase transition of a hot and dense system of quarks is studied within a modified SU(3) NJL Lagrangian that implements the QCD scale anomaly. The u- and s-quark condensates can or can not feel the same chiral restoration depending on the considered region of the three-dimensional space (Tc, muuc, musc). The temperature behaviour of the pressure and the energy and entropy densities of the u- and s-quark system is investigated. At high temperature, the non-vanishing bare s-quark mass only modifies slightly the usual behaviour associated with an ideal quark gas. [less ▲] Detailed reference viewed: 10 (1 ULg)Anomalous pion decay in effective QCD at finite temperature ; Jaminon, Martine ; et al in Nuclear Physics A (1995), 592 The width of the process π0 → γγ is calculated within effective QCD at finite temperature. We use two different effective models which describe chiral symmetry breaking and its restoration at finite ... [more ▼] The width of the process π0 → γγ is calculated within effective QCD at finite temperature. We use two different effective models which describe chiral symmetry breaking and its restoration at finite temperature in SU(2)ƒ: (i) an effective lagrangian with a nonlocal separable interaction kernel, (ii) A- and B-scaledNJL lagrangians which implement the scale anomaly of QCD. We calculate the temperature dependences of the quark and pion masses as well as of the pion-park-antiquark coupling strength below and above the double quark mass threshold. At zero temperature we obtain a fairly good agreement with the experimental value for the decay width. The temperature dependence of the decay width is related to that of the pion mass. Γπ0 → γγ is enhanced in the vicinity of the Mott temperature (Mπ = 2mq) for the nonlocal as well as for the A-scaled model and suppressed for the B-scaled model. We compare our results with the SU(2) Nambu-Jona-Lasinio model which is contained as a limiting case in our approach. [less ▲] Detailed reference viewed: 24 (2 ULg)SU (3) scaled effective lagrangians for a hot and strange system Jaminon, Martine ; in Nuclear Physics A (1995), 582 We construct two effective lagrangians which reproduce the explicit flavor SU(3) symmetry breaking and the trace and axial anomalies of QCD. All analytical expressions are derived for a hot strange matter ... [more ▼] We construct two effective lagrangians which reproduce the explicit flavor SU(3) symmetry breaking and the trace and axial anomalies of QCD. All analytical expressions are derived for a hot strange matter but the results are only shown for zero baryonic density. We study the coupling of the quark condensates (u and s) to the gluon condensate. We also consider the temperature behavior of the pion and of the kaon masses. We show that the results crucially depend on the choice of the two free parameters of the model: the chiral transition can be of first or of second order; the coupling between the gluon and the quark condensates can be large or not; the meson masses can increase or decrease with temperature. The introduction of the QCD trace anomaly in the SU(3) NJL model kills the predictive character of the NJL. [less ▲] Detailed reference viewed: 17 (6 ULg)The coupling of quark and gluon condensates in hot and dense systems Jaminon, Martine ; in Nuclear Physics A (1994), 567 Detailed reference viewed: 7 (1 ULg)Chiral theory of mesons in dense baryonic matter (II) : Meson propagation Jaminon, Martine ; ; Stassart, Pierre in Nuclear Physics A (1993), 556 Detailed reference viewed: 10 (1 ULg)Scaled effective chiral lagrangians for the propagation of scalar and vector mesons in dense matter Jaminon, Martine ; in Nuclear Physics A (1993), 564 Detailed reference viewed: 1 (0 ULg)Effect of the vector-axial-vector coupling on the vector-meson modes Jaminon, Martine ; in Nuclear Physics A (1993), 564 Detailed reference viewed: 8 (0 ULg) |
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