122074768
Doubly charmed exotic mesons: A gift of nature?
Article history: We study doubly charmed exotic states by solving the scattering problem of two D mesons. Our results point to the existence of a stable isoscalar doubly charmed meson with quantum numbers (I) J P = (0)1 + . We perform a thorough comparison to the results obtained within the hyperspherical harmonic formalism. Such exotic states could be measured at LHC and RHIC. Their experimental observation would,
120223418
Heavy hadron spectroscopy: A quark model perspective
Abstract We present recent results of hadron spectroscopy and hadron–hadron interaction from the perspective of constituent quark models. We pay special attention to the role played by higher order Fock space components in the hadron spectra and the connection of this extension with the hadron–hadron interaction. The main goal of our description is to obtain a coherent understanding of the low-energy hadron phenomenology without enforcing any particular model, to constrain its characteristics and learn about low-energy realization of the theory.
119867295
The $N\Lambda \Lambda -\Xi NN$ bound state problem
We use a diagrammatic method to derive the Faddeev equations of the coupled NΛΛ–ΞNN system and apply them to the bound-state problem of the channel. We use as input the nucleon–nucleon, nucleon–hyperon and hyperon–hyperon interactions obtained from a chiral constituent quark model. We explore different parametrizations of the quark–quark interacting potential. While the system alone is unbound, the full coupled channel problem NΛΛ–ΞNN may present a three-baryon bound state just below threshold. Different from double- hypernuclei with four nucleons or more, where the Pauli principle acts strongly because there is no room for more that four nucleons in S wave, in H the full interaction can act in S wave.
188638461
Too many $X's$, $Y's$ and $Z's$?
189904940
Multiquark Systems
In this talk we tackle the description of hadron spectroscopy in terms of the constituent quark model. We focus on the mesonic charm sector, where several of the new reported resonances seem to defy their classification as simple quark-antiquark states. We pay special attention to higher order Fock space components in describing excited states of the meson spectra in close connection with the hadron-hadron interaction. The main goal of the present study is a coherent understanding of the low-energy hadron phenomenology without enforcing any particular model, to constrain its characteristics and learn about low-energy realization of the theory.
121248392
Charged charmonium molecules
We make use of a self-consistent quark-model based study of four-quark charmonium-like states to interpret recent charmonium experimental data. We conclude that there exists a D*D* meson-meson molecule with quantum numbers (I{sup G})J{sup PC}=(1{sup -})2{sup ++}. Our study confirms the presence of charged charmonium-like resonances on the excited charmonium spectrum. We find support from recent experimental data by the Belle Collaboration [R. Mizuk et al. (Belle Collaboration), Phys. Rev. D 78, 072004 (2008)]. Confirmation of the experimental data by the Belle Collaboration and the determination of the quantum numbers of the new structures would help in discriminating among different theoretical models and would give further support to the theoretical analysis of T. Fernandez-Carames, A. Valcarce, and J. Vijande [Phys. Rev. Lett. 103, 222001 (2009)].
118504967
Nonlinear dark matter collapse under diffusion
Diffusion is one of the physical processes allowed for describing the large scale dark matter dynamics. At the same time, it can be seen as a possible mechanism behind the interacting cosmologies. We study the non-linear spherical "top-hat" collapse of dark matter which undergoes velocity diffusion into a solvent dark energy field. We show constraints on the maximum magnitude allowed for the dark matter diffusion. Our results reinforce previous analysis concerning the linear perturbation theory.
118412284
Spherical collapse for unified dark matter models
We study the non-linear spherical "top hat" collapse for Chaplygin and viscous unified cosmologies. The term unified refers to models where dark energy and dark matter are replaced by one single component. For the generalized Chaplygin gas (GCG) we extend previous results of [R. A. A. Fernandes {\it et al}. Physical Review D 85, 083501 (2012)]. We discuss the differences at non-linear level between the GCG with $\alpha=0$ and the $\Lambda$CDM model. We show that both are indeed different. The bulk viscous model which differs from the GCG due to the existence of non-adiabatic perturbations is also studied. In this case, the clustering process is in general suppressed and the viable parameter space of the viscous model that accelerates the background expansion does not lead to collapsed structures. This result challenges the viability of unified viscous models.
118427849
Structure formation in a $\Lambda$ $viscous$ CDM universe
The possibility of dark matter being a dissipative component represents an option for the standard view where cold dark matter (CDM) particles behave on large scales as an ideal fluid. By including a physical mechanism to the dark matter description like viscosity we construct a more realistic model for the universe. Also, the known small scale pathologies of the standard CDM model either disappear or become less severe. We study clustering properties of a $\Lambda$CDM-like model in which dark matter is described as a bulk viscous fluid. The linear power spectrum, the nonlinear spherical "top hat" collapse and the mass functions are presented. We use the analysis with such structure formation tools in order to place an upper bound on the magnitude of the dark matter's viscosity.
119237428
GRAVITATIONAL FIELD OF A GLOBAL MONOPOLE IN A MODIFIED GRAVITY
In this paper we analyze the gravitational field of a global monopole in the context of f(R) gravity. More precisely, we show that the field equations obtained are expressed in terms of $F(R) = \frac{df(R)}{dR}$. Since we are dealing with a spherically symmetric system, we assume that F(R) is a function of the radial coordinate only. Moreover, adopting the weak field approximation, we can provide all components of the metric tensor. A comparison with the corresponding results obtained in General Relativity and in the Brans-Dicke theory is also made.
119180568
Effective gravitational equations for $f(R)$ braneworld models
Instituto de Fisica Universidade Federal Fluminense, Avenue Gal. Milton Tavares de Souza, s/n, CEP 24210-346 Niteroi-Rio de Janeiro