13
13
Jun 28, 2018
06/18
by
H. Garcilazo; A. Valcarce
texts
eye 13
favorite 0
comment 0
It has been recently suggested the existence of a neutral bound state of two neutrons and a $\Lambda$ hyperon, $^3_\Lambda n$. We point out that using either simple separable potentials or a full-fledged calculation with realistic baryon-baryon interactions derived from the constituent quark cluster model there is no possibility for the existence of such a $\Lambda nn$ bound state. For this purpose, we performed a full Faddeev calculation of the $\Lambda nn$ system in the $(I,J^P)=(1,1/2^+)$...
Topics: High Energy Physics - Phenomenology, Nuclear Theory
Source: http://arxiv.org/abs/1507.08061
38
38
Sep 23, 2013
09/13
by
A. Valcarce; J. Vijande
texts
eye 38
favorite 0
comment 0
We present recent studies of charmonium multiquark states. We use different interacting models and numerical methods to study deeply bound four-quark states and meson-meson molecules. No deeply bound four-quark states are found in our analysis. A nice description of the X(3872) is obtained as a $D\bar{D}^*-J/\Psi\omega$ coupled channel state.
Source: http://arxiv.org/abs/1012.4630v1
7
7.0
Jun 29, 2018
06/18
by
H. Garcilazo; A. Valcarce
texts
eye 7
favorite 0
comment 0
The recent update of the strangeness $-2$ ESC08c Nijmegen potential incorporating the NAGARA and KISO events predicts a $\Xi N$ bound state, $D^*$, in the $^3S_1 (I=1)$ channel. We study if the existence of this two-body bound state could give rise to stable three-body systems. For this purpose we solve the bound state problem of three-body systems where the $\Xi N$ state is merged with $N$'s, $\Lambda$'s, $\Sigma's$ or $\Xi$'s, making use of the most recent updates of the two-body ESC08c...
Topics: High Energy Physics - Phenomenology, Nuclear Theory
Source: http://arxiv.org/abs/1606.08767
43
43
Sep 22, 2013
09/13
by
J. Vijande; A. Valcarce
texts
eye 43
favorite 0
comment 0
Four-quark states may exist as colorless meson-meson molecules or compact systems with two-body colored components. We derive an analytical procedure to expand an arbitrary four--quark wave function in terms of nonorthogonal color singlet--singlet vectors. Using this expansion we develop the necessary formalism to evaluate the probability of physical components with an arbitrary four-quark wave function. Its application to characterize bound and unbound four--quark states as meson-meson,...
Source: http://arxiv.org/abs/0908.3254v1
81
81
Sep 17, 2013
09/13
by
H. Garcilazo; A. Valcarce
texts
eye 81
favorite 0
comment 0
We calculate the doublet and quartet neutron-deuteron scattering lengths using a nonlocal nucleon-nucleon interaction fully derived from quark-quark interactions. We use as input the $NN$ $^1S_0$ and $^3S_1$-${}^3 D_1$ partial waves. Our result for the quartet scattering length agrees well with the experimental value while the result for the doublet scattering length does not. However, if we take the result for the doublet scattering length together with the one for the triton binding energy...
Source: http://arxiv.org/abs/0711.3123v1
3
3.0
Jun 29, 2018
06/18
by
H. Garcilazo; A. Valcarce
texts
eye 3
favorite 0
comment 0
We have used realistic local interactions based on the recent update of the strangeness $-2$ Nijmegen ESC08c potential to calculate the bound state problem of the $\Xi NN$ system in the $(I)J^P=(\frac{1}{2})\frac{3}{2}^+$ state. We found that this system presents a deeply bound state lying $13.5$ MeV below the $\Xi d$ threshold. Since in lowest order, pure S$-$wave configuration, this system can not decay into the open $\Lambda\Lambda N$ channel, its decay width is expected to be very small. We...
Topics: High Energy Physics - Phenomenology, Nuclear Theory
Source: http://arxiv.org/abs/1605.04108
5
5.0
Jun 29, 2018
06/18
by
A. Valcarce; J. Vijande
texts
eye 5
favorite 0
comment 0
In this talk we present a mechanism giving rise to exotic $XYZ$ four-quark states in the meson spectra within a constituent quark model approach. We discuss its generalization to five-quark states in the heavy baryon sector. Finally, we revise some other works in the literature and experimental data where this mechanism may be working.
Topics: High Energy Physics - Phenomenology, Nuclear Theory
Source: http://arxiv.org/abs/1605.04107
45
45
Sep 22, 2013
09/13
by
J. Vijande; A. Valcarce
texts
eye 45
favorite 0
comment 0
The physics of charm has become one of the best laboratories exposing the limitations of the naive constituent quark model and also giving hints into a more mature description of meson spectroscopy, beyond the simple quark--antiquark configurations. In this talk we review some recent studies of multiquark components in the charm sector and discuss in particular exotic and non-exotic four-quark systems.
Source: http://arxiv.org/abs/1001.4876v1
35
35
Jul 20, 2013
07/13
by
H. Garcilazo; A. Valcarce
texts
eye 35
favorite 0
comment 0
In this Reply we argue that the conclusions derived in Ref. arXiv:1301.1241 are questionable.
Source: http://arxiv.org/abs/1304.3552v1
14
14
Jun 28, 2018
06/18
by
J. Vijande; A. Valcarce
texts
eye 14
favorite 0
comment 0
We present a plausible mechanism for the origin of the $XYZ$ mesons in the heavy meson spectra within a standard quark-model picture. We discuss the conditions required for the existence of four--quark bound states or resonances contributing to the heavy meson spectra, being either compact or molecular. We concentrate on charmonium and bottomonium spectra, where several new states, difficult to understand as simple quark-antiquark pairs, have been reported by different experimental...
Topics: High Energy Physics - Phenomenology, Nuclear Theory
Source: http://arxiv.org/abs/1507.08045
42
42
Sep 21, 2013
09/13
by
J. Vijande; A. Valcarce
texts
eye 42
favorite 0
comment 0
In this letter we present a solution to describe simultaneously the light isoscalar and isovector vector mesons in constituent quark models. In Ref. [1] the $q\bar q$ spectrum was studied in a generalized constituent quark model constrained by the $NN$ phenomenology and the baryon spectrum. An overall good fit to the available experimental data was obtained. A major problem of this description was the relative position of the vector $\omega$ and $\rho$ mesons. The present results improve the...
Source: http://arxiv.org/abs/0905.1817v1
45
45
Sep 17, 2013
09/13
by
A. Valcarce; J. Vijande
texts
eye 45
favorite 0
comment 0
We study charmonium ($c\bar c n\bar n$), bottomonium ($b\bar b n\bar n$) and exotic ($cc\bar n\bar n$ and $bb\bar n\bar n$) four-quark states by means of a standard non-relativistic quark potential model. We look for possible bound states. Among them we are able to distinguish between meson-meson molecules and compact four-quark states.
Source: http://arxiv.org/abs/0912.3080v1
12
12
Jun 28, 2018
06/18
by
H. Garcilazo; A. Valcarce
texts
eye 12
favorite 0
comment 0
Arguments in favor of a light $\Xi NN$ hypernucleus with $(I)J^P=(3/2)1/2^+$ are presented, within the uncertainties of our knowledge of the baryon-baryon strangeness $-2$ interactions. If bound, this $\Xi NN$ state, being decoupled from the lowest $N\Lambda\Lambda$ system, would be stable. It will also benefit from additional binding due to the electromagnetic interaction what makes it worthwhile to look for. We show how the equivalent state with $J=3/2$ could never be bound in spite of the...
Topics: High Energy Physics - Phenomenology, Nuclear Theory
Source: http://arxiv.org/abs/1507.03733
40
40
Sep 22, 2013
09/13
by
H. Garcilazo; A. Valcarce
texts
eye 40
favorite 0
comment 0
The non-strange baryon spectrum is studied within a three-body model that incorporates relativistic kinematics. We found that the combined effect of relativistic kinematics together with the pion exchange between quarks is able to reverse the order of the first positive- and negative-parity nucleon excited states as observed experimentally. Including the chiral partner of the pion (the $\sigma$ meson) leads to an overall good description of the spectrum.
Source: http://arxiv.org/abs/hep-ph/0308023v1
44
44
Sep 17, 2013
09/13
by
J. Vijande; A. Valcarce
texts
eye 44
favorite 0
comment 0
We present a detailed analysis of the symmetry properties of a four-quark wave function and its solution by means of a variational approach for simple Hamiltonians. We discuss several examples in the light and heavy-light meson sector.
Source: http://arxiv.org/abs/0912.3605v1
40
40
Sep 23, 2013
09/13
by
H. Garcilazo; A. Valcarce
texts
eye 40
favorite 0
comment 0
We have solved for the first time the Faddeev equations for the bound state problem of the coupled $\Lambda\Lambda N$--$\Xi NN$ system to study whether an hypertriton with strangeness -2 may exist or not. We make use of the interactions obtained from a chiral quark model describing the low-energy observables of the two-baryon systems with strangeness 0, -1, and -2 and three-baryon systems with strangeness 0 and -1. The $\Lambda\Lambda N$ system alone is unbound. However, when the full coupling...
Source: http://arxiv.org/abs/1212.1369v1
46
46
Sep 21, 2013
09/13
by
T. F. Carames; A. Valcarce
texts
eye 46
favorite 0
comment 0
We study the $N \bar D$ system by means of a chiral constituent quark model. This model, tuned in the description of the baryon and meson spectra as well as the $NN$ interaction, provides parameter-free predictions for the charm -1 two-hadron systems. The presence of a heavy antiquark makes the interaction rather simple. We have found sharp quark-Pauli effects in some particular channels, generating repulsion, due to lacking degrees of freedom to accommodate the light quarks. Our results point...
Source: http://arxiv.org/abs/1204.5502v1
58
58
Sep 21, 2013
09/13
by
T. F. Carames; A. Valcarce
texts
eye 58
favorite 0
comment 0
We perform a coupled--channel calculation of the H dibaryon within a chiral constituent quark model. The problem is solved within a quark model constrained by the experimental data of strangeness --1 and --2 two--baryon systems. We examine in detail the role played by the different contributions of the interacting potential as well as the number of coupled channels considered. Special attention has been payed to the parameter dependence, flavor symmetry breaking and spatial configurations. The...
Source: http://arxiv.org/abs/1204.5683v1
9
9.0
Jun 28, 2018
06/18
by
T. F. Carames; A. Valcarce
texts
eye 9
favorite 0
comment 0
We study the two-baryon system with two units of charm looking for the possible existence of a loosely bound state resembling the $H$ dibaryon. We make use of a chiral constituent quark model tuned in the description of the baryon and meson spectra as well as the $NN$ interaction. The presence of the heavy quarks makes the interaction simpler than in light baryon systems. We analyze possible quark-Pauli effects that would be present in spin-isospin saturated channels. Our results point to the...
Topics: High Energy Physics - Phenomenology, Nuclear Theory
Source: http://arxiv.org/abs/1507.08278
12
12
Jun 28, 2018
06/18
by
T. F. Carames; A. Valcarce
texts
eye 12
favorite 0
comment 0
We study possible multiquark contributions to the charm baryon spectrum by considering higher order Fock space components. For this purpose we perform two different calculations. In a first approach we do a coupled-channel calculation of the $ND$ system looking for molecular states. In a second step we allow for the coupling to a heavy baryon--light meson two-hadron system looking for compact exotic five--quark structures. Both calculations have been done within the framework of a chiral...
Topics: High Energy Physics - Phenomenology, Nuclear Theory
Source: http://arxiv.org/abs/1507.08046
4
4.0
Jun 29, 2018
06/18
by
T. F. Caramés; A. Valcarce
texts
eye 4
favorite 0
comment 0
We present a neat example of a meson--baryon system where the vicinity of two different thresholds enhances the binding of a hadronic resonance, a pentaquark. As a consequence the pattern of states may change when moving among different flavor sectors, what poses a warning on naive extrapolations to heavy flavor sectors based on systematic expansions. For this purpose we simultaneously analyze the $N\bar D$ and $NB$ two-hadron systems looking for possible bound states or resonances. When a...
Topics: High Energy Physics - Phenomenology, Nuclear Theory
Source: http://arxiv.org/abs/1605.04428
55
55
Sep 20, 2013
09/13
by
J. Vijande; F. Fernandez; A. Valcarce
texts
eye 55
favorite 0
comment 0
We present a theoretical framework that accounts for the new $D_J$ and $D_{sJ}$ mesons measured in the open-charm sector. These resonances are properly described if considered as a mixture of conventional $P-$wave quark-antiquark states and four-quark components. The narrowest states are basically $P-$wave quark-antiquark mesons, while the dominantly four-quark states are shifted above the corresponding two-meson threshold, being broad resonances. We study the electromagnetic decay widths as...
Source: http://arxiv.org/abs/hep-ph/0601143v1
41
41
Sep 23, 2013
09/13
by
H. Garcilazo; A. Valcarce; F. Fernandez
texts
eye 41
favorite 0
comment 0
We have performed a Faddeev calculation of the baryon spectrum for the chiral constituent quark model including higher orbital angular momentum states. We have found that the effect of these states is important, although a description of the baryon spectrum of the same quality as the one given by including only the lowest-order configurations can be obtained. We have studied the effect of the pseudoscalar quark-quark interaction on the relative position of the positive- and negative-parity...
Source: http://arxiv.org/abs/nucl-th/0109004v1
46
46
Jul 24, 2013
07/13
by
A. Valcarce; H. Garcilazo; J. Vijande
texts
eye 46
favorite 0
comment 0
The recent observation at CDF and D0 of $\Sigma_b$, $\Sigma^*_b$ and $\Xi_b$ baryons opens the door to the advent of new states in the bottom baryon sector. The states measured provide sufficient constraints to fix the parameters of phenomenological models. One may therefore consistently predict the full bottom baryon spectra. For this purpose we have solved exactly the three-quark problem by means of the Faddeev method in momentum space. We consider our guidance may help experimentalists in...
Source: http://arxiv.org/abs/0807.2973v1
36
36
Sep 18, 2013
09/13
by
A. Valcarce; F. Fernandez; H. Garcilazo
texts
eye 36
favorite 0
comment 0
We calculated the mass and width of the $d'$ resonance inside nuclei within a nucleon-$\Delta$ model by including the self-energy of the $\Delta$ in the $N\Delta$ propagator. We found that in the nuclear medium the width of the $d'$ is increased by one order of magnitude while its mass changes only by a few MeV. This broadening of the width of the $d'$ resonance embedded in nuclei is consistent with the experimental observations so that the $d'$ can be understood as a $N\Delta$ resonance. Thus,...
Source: http://arxiv.org/abs/nucl-th/9606036v1
34
34
Sep 23, 2013
09/13
by
J. Vijande; A. Valcarce; N. Barnea
texts
eye 34
favorite 0
comment 0
We present an exact calculation of $S$ and $P$ wave $QQ\bar n\bar n$ states using different standard nonrelativistic quark--quark potentials. We explore in detail the charm and bottom sectors looking for bound states that could be measured within existing facilities. Against the proliferation of four--quark states sometimes predicted in the literature, we found a small number of candidates to be stable. We analyze their properties in a trial to distinguish between compact and molecular states....
Source: http://arxiv.org/abs/0903.2949v1
38
38
Sep 20, 2013
09/13
by
J. Vijande; A. Valcarce; K. Tsushima
texts
eye 38
favorite 0
comment 0
It has been recently conjectured by Selem and Wilczek \cite{Sel06} the existence of a $ss-[\bar u \bar d]$ meson due to strong correlations between the two light antiquarks. We make a detailed study of this system within a dynamical quark model which has proven to be successful in reproducing the most important features of low-energy hadron phenomenology. Our results, obtained within a parameter-free calculation, show that the antidiquark component of the $ss \bar u \bar d$ system indeed...
Source: http://arxiv.org/abs/hep-ph/0608316v1
49
49
Sep 19, 2013
09/13
by
J. Vijande; N. Barnea; A. Valcarce
texts
eye 49
favorite 0
comment 0
We present a generalization of the hyperspherical harmonic formalism to study systems made of quarks and antiquarks of the same flavor. This generalization is based on the symmetrization of the $N-$body wave function with respect to the symmetric group using the Barnea and Novoselsky algorithm. Our analysis shows that four-quark systems with non-exotic $2^{++}$ quantum numbers may be bound independently of the quark mass. $0^{+-}$ and $1^{+-}$ states become attractive only for larger quarks...
Source: http://arxiv.org/abs/hep-ph/0610124v1
4
4.0
Jun 29, 2018
06/18
by
H. Garcilazo; A. Valcarce; J. Vijande
texts
eye 4
favorite 0
comment 0
This paper provides results for the ground state and excited spectra of three-flavored doubly heavy baryons, $bcn$ and $bcs$. We take advantage of the spin-independent interaction recently obtained to reconcile the lattice SU(3) QCD static potential and the results of nonperturbative lattice QCD for the triply heavy baryon spectra. We show that the spin-dependent potential might be constrained on the basis of nonperturbative lattice QCD results for the spin splittings of three-flavored doubly...
Topics: High Energy Physics - Phenomenology, Nuclear Theory
Source: http://arxiv.org/abs/1609.06886
6
6.0
Jun 29, 2018
06/18
by
H. Garcilazo; A. Valcarce; J. Vijande
texts
eye 6
favorite 0
comment 0
By using local central Yukawa-type interactions that reproduce the low-energy parameters of the latest updates of the Nijmegen ESC08c potentials we show that the $N\Xi$, $NN\Xi$, $N\Xi\Xi$ and $NN\Xi\Xi$ systems with maximal isospin are bound. Since in these states the strong decay $N\Xi\to\Lambda\Lambda$ is forbidden by isospin conservation, these strange few-body systems will be stable under the strong interaction. These results may suggest that other states with different number of $N$'s and...
Topics: High Energy Physics - Phenomenology, Nuclear Theory
Source: http://arxiv.org/abs/1608.05192
50
50
Sep 22, 2013
09/13
by
J. Vijande; F. Fernandez; A. Valcarce
texts
eye 50
favorite 0
comment 0
The ${q}\bar{q}$ spectrum is studied within a chiral constituent quark model. It provides with a good fit of the available experimental data from light (vector and pseudoscalar) to heavy mesons. The new $D$ states measured at different factories are studied. The $0^{++}$ light mesons are analyzed as $q\bar q$ pairs or tetraquark structures.
Source: http://arxiv.org/abs/hep-ph/0308318v2
55
55
Sep 21, 2013
09/13
by
J. Vijande; F. Fernandez; A. Valcarce
texts
eye 55
favorite 0
comment 0
Despite the apparent simplicity of meson spectroscopy there are some states which cannot be accommodated in the usual $q\bar q$ structure. Among them there are either exotic states as the X(1600) or the recently measured charm states $D_{sJ}^*$ and X(3872) and some of the light scalar mesons. In this work we present a possible description of these states in terms of tetraquarks.
Source: http://arxiv.org/abs/hep-ph/0407136v1
39
39
Sep 19, 2013
09/13
by
J. Vijande; F. Fernandez; A. Valcarce
texts
eye 39
favorite 0
comment 0
We present a theoretical framework that accounts for the new $D_J$ and $D_{sJ}$ mesons measured in the open-charm sector. These resonances are properly described if considered as a mixture of conventional $P-$wave quark-antiquark states and four-quark components. The narrowest states are basically $P-$wave quark-antiquark mesons, while the dominantly four-quark states are shifted above the corresponding two-meson threshold. We study the electromagnetic decay widths as basic tools to scrutiny...
Source: http://arxiv.org/abs/hep-ph/0610126v1
79
79
Sep 18, 2013
09/13
by
A. Valcarce; F. Fernandez; H. Garcilazo
texts
eye 79
favorite 0
comment 0
Based on a quark cluster model for the non-strange sector that reproduces reasonably well the nucleon-nucleon system and the excitation of the $\Delta$ isobar, we generate a nucleon-$\Delta$ interaction and present the predictions for the several isospin two channels. The only attractive channels are $0^+$ and $0^-$, but not attractive enough to generate a resonance. If a resonance is artificially generated and is required to have the observed experimental mass, then our model predicts a width...
Source: http://arxiv.org/abs/nucl-th/9509012v1
53
53
Sep 19, 2013
09/13
by
J. Vijande; N. Barnea; A. Valcarce
texts
eye 53
favorite 0
comment 0
We present an exact method based on a hyperspherical harmonic expansion to study systems made of quarks and antiquarks of the same flavor. Our formalism reproduces and improves the results obtained with variational approaches. This analysis shows that identical-flavor four-quark systems with non-exotic $2^{++}$ quantum numbers may be bound independently of the quark mass. $0^{+-}$ and $1^{+-}$ states become attractive only for larger quarks masses.
Source: http://arxiv.org/abs/hep-ph/0610287v1
46
46
Sep 23, 2013
09/13
by
J. Vijande; F. Fernandez; A. Valcarce
texts
eye 46
favorite 0
comment 0
The $q\bar q$ spectrum is studied in a generalized constituent quark model constrained in the study of the $NN$ phenomenology and the baryon spectrum. An overall good fit to the available experimental data is obtained. A detailed analysis of all sectors from the light-pseudoscalar and vector mesons to bottomonium is performed paying special attention to the existence and nature of some non well-established states. These results should serve as a complementary tool in distinguishing conventional...
Source: http://arxiv.org/abs/hep-ph/0411299v2
33
33
Sep 19, 2013
09/13
by
A. Valcarce; H. Garcilazo; J. Vijande
texts
eye 33
favorite 0
comment 0
We investigate the structure of the SU(3) octet and decuplet baryons employing a constituent quark model designed for the study of the baryon-baryon interaction and successfully applied to the meson spectra. The model considers through the interacting potential perturbative, one-gluon exchange, and non-perturbative, boson exchanges and confinement, aspects of the underlying theory, QCD. We solve the three-quark problem by means of the Faddeev method in momentum space. We analyze the effect of...
Source: http://arxiv.org/abs/hep-ph/0507297v1
10
10.0
Jun 28, 2018
06/18
by
J. Vijande; A. Valcarce; H. Garcilazo
texts
eye 10
favorite 0
comment 0
This paper provides results for the spectra of triply charmed and bottom baryons based on a constituent quark model approach. We take advantage of the assumption that potential models are expected to describe triply heavy baryons to a similar degree of accuracy as the successful results obtained in the charmonium and bottomonium sectors. The high precision calculation of the ground state and positive and negative parity excited states recently reported by nonperturbative lattice QCD provides us...
Topics: High Energy Physics - Phenomenology, Nuclear Theory, High Energy Physics - Lattice, High Energy...
Source: http://arxiv.org/abs/1507.03735
50
50
Sep 20, 2013
09/13
by
J. Vijande; F. Fernandez; A. Valcarce
texts
eye 50
favorite 0
comment 0
Despite the apparent simplicity of meson spectroscopy there are some states which cannot be accommodated in the usual $q\bar q$ structure. Among them there are either exotic states as the X(1600), or the recently measured charmed states $D_{sJ}^*$ and some of the light scalar mesons. We present a description of the light scalar mesons in terms of $q\bar q$ and $qq\bar q\bar q$ components.
Source: http://arxiv.org/abs/hep-ph/0410008v1
45
45
Sep 23, 2013
09/13
by
J. Vijande; A. Valcarce; F. Fernandez
texts
eye 45
favorite 0
comment 0
Within a theoretical framework that accounts for all open-charm mesons, including the $D_0^*(2308)$, the $D_{sJ}^*(2317)$ and the $D_{sJ}(2460)$, we analyze the structure and explore possible quantum number assignments for the $D_{sJ}(2860)$ and the $D_{sJ}(2700)$ mesons reported by BABAR and Belle Collaborations. The open-charm sector is properly described if considered as a combination of conventional quark-antiquark states and four--quark components. All negative parity and $2^+$ states can...
Source: http://arxiv.org/abs/0810.4988v2
50
50
Sep 17, 2013
09/13
by
J. Vijande; A. Valcarce; F. Fernandez
texts
eye 50
favorite 0
comment 0
We study the $B$ meson spectroscopy allowing the mixture of conventional $P$ wave quark-antiquark states and four-quark components. A similar picture was used to describe the new $D_J$ and $D_{sJ}$ open charm mesons. The four-quark components shift the masses of some positive parity $B_{sJ}$ states below their corresponding isospin preserving two-meson threshold and therefore they are expected to be narrow. Electromagnetic decay widths are analyzed.
Source: http://arxiv.org/abs/0711.2359v1
136
136
Sep 18, 2013
09/13
by
A. Valcarce; F. Fernandez; P. Gonzalez
texts
eye 136
favorite 0
comment 0
We review the actual state in the description of the NN interaction by means of chiral constituent quark models. We present a series of relevant features that are nicely explained within the quark model framework.
Source: http://arxiv.org/abs/nucl-th/0212044v1
62
62
Sep 21, 2013
09/13
by
J. Vijande; G. Krein; A. Valcarce
texts
eye 62
favorite 0
comment 0
We perform a quark model calculation of the quarkonia $b\overline{b}$ and $c\overline{c}$ spectra using smooth and sudden string breaking potentials. The screening parameter is scale dependent and can be related to an effective running gluon mass that has a finite infrared fixed point. A temperature dependence for the screening mass is motivated by lattice QCD simulations at finite temperature. Qualitatively different results are obtained for quarkonia properties close to a critical value of...
Source: http://arxiv.org/abs/0902.3570v1
45
45
Sep 21, 2013
09/13
by
J. Vijande; F. Fernandez; A. Valcarce
texts
eye 45
favorite 0
comment 0
We present a quark-quark interaction for the complete study of the meson spectra, from the light to the heavy sector. We compare the quark model predictions against well-established $q\bar q$ experimental data. This allows to identify discrepancies between quark model results and experiment that may signal physics beyond conventional hadron spectroscopy.
Source: http://arxiv.org/abs/hep-ph/0407135v1
31
31
Jul 20, 2013
07/13
by
N. Barnea; J. Vijande; A. Valcarce
texts
eye 31
favorite 0
comment 0
We present a generalization of the hyperspherical harmonic formalism to study systems made of quarks and antiquarks of the same flavor. This generalization is based on the symmetrization of the $N-$body wave function with respect to the symmetric group using the Barnea and Novoselsky algorithm. The formalism is applied to study four-quark systems by means of a constituent quark model successful in the description of the two- and three-quark systems. The results are compared to those obtained by...
Source: http://arxiv.org/abs/hep-ph/0604010v1
111
111
Sep 17, 2013
09/13
by
A. Valcarce; J. Vijande; N. Barnea
texts
eye 111
favorite 0
comment 0
The physics of charm has become one of the best laboratories exposing the limitations of the naive constituent quark model and also giving hints into a more mature description of hadron spectroscopy. Recent discoveries are a challenge that have revolutionized our understanding of the hadron spectra. In this talk we address the study of many-quark components in charmonium spectra. To make the physics clear we also discuss exotic many-quark systems.
Source: http://arxiv.org/abs/0711.3114v1
10
10.0
Jun 28, 2018
06/18
by
J. Vijande; A. Valcarce; H. Garcilazo
texts
eye 10
favorite 0
comment 0
The ground state and excited spectra of baryons containing three identical heavy quarks, $b$ or $c$, have been recently calculated in nonperturbative lattice QCD. The energy of positive and negative parity excitations has been determined with high precision. Lattice results constitute a unique opportunity to learn about the quark-confinement mechanism as well as elucidating our knowledge about the nature of the strong force. We analyze the nonperturbative lattice QCD results by means of...
Topics: High Energy Physics - Phenomenology, Nuclear Theory, High Energy Physics - Lattice, High Energy...
Source: http://arxiv.org/abs/1507.03736
54
54
Sep 22, 2013
09/13
by
J. Vijande; F. Fernandez; A. Valcarce
texts
eye 54
favorite 0
comment 0
The ${q}\bar{q}$ spectrum is studied within a chiral constituent quark model. It provides with a good fit of the available experimental data from light (vector and pseudoscalar) to heavy mesons including some recent results on charmonium. The $0^{++}$ light mesons and the new $D$ states measured at different factories cannot be described as $q\bar q$ pairs and a tetraquark structure is suggested.
Source: http://arxiv.org/abs/hep-ph/0309319v2
44
44
Sep 22, 2013
09/13
by
P. Gonzalez; J. Vijande; A. Valcarce
texts
eye 44
favorite 0
comment 0
We argue that selected $S$ wave meson-baryon channels may play a key role to match poor baryon mass predictions from quark models with data. The identification of these channels with effective inelastic channels in data analysis allows to derive a prescription which could improve the extraction and identification of baryon resonances.
Source: http://arxiv.org/abs/0805.4677v1
41
41
Sep 19, 2013
09/13
by
H. Garcilazo; J. Vijande; A. Valcarce
texts
eye 41
favorite 0
comment 0
We investigate the structure of heavy baryons containing a charm or a bottom quark. We employ a constituent quark model successful in the description of the baryon-baryon interaction which is consistent with the light baryon spectra. We solve exactly the three-quark problem by means of the Faddeev method in momentum space. Heavy baryon spectrum shows a manifest compromise between perturbative and nonperturbative contributions. The flavor dependence of the one-gluon exchange is analyzed. We...
Source: http://arxiv.org/abs/hep-ph/0703257v1
