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H. Garcilazo

Publications and source records attributed to H. Garcilazo.

At least 37 records · Page 2Linked to original sources
arXiv2017

Workshop on Excited Hyperons in QCD Thermodynamics at Freeze-Out (YSTAR2016) Mini-Proceedings

This Workshop brought top experts, researchers, postdocs, and students from high-energy heavy ion interactions, lattice QCD and hadronic physics communities together. YSTAR2016 discussed the impact of "missing" hyperon resonances on QCD thermodynamics, on freeze-out in heavy ion collisions, on the evolution of early universe, and on the spectroscopy of strange particles. Recent studies that compared lattice QCD predictions of thermodynamic properties of quark-gluon plasma at freeze-out with calculations based on statistical hadron resonance gas models as well as experimentally measured ratios between yields of different hadron species in heavy ion collisions provide indirect evidence for the presence of "missing" resonances in all of these contexts. The aim of the YSTAR2016 Workshop was to sharpen these comparisons and advance our understanding of the formation of strange hadrons from quarks and gluons microseconds after the Big Bang and in todays experiments at LHC and RHIC as well as at future facilities like FAIR, J-PARC and KL at JLab. It was concluded that the new initiative to create a secondary beam of neutral kaons at JLab will make a bridge between the hardron spectroscopy, heavy-ion experiments and lattice QCD studies addressing some major issues related to thermodynamics of the early universe and cosmology in general.

hep-ph↗
arXiv2016

Doubly heavy baryon spectra guided by lattice QCD

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 heavy baryons. Our results may also represent a challenge for future lattice QCD work, because a smaller lattice error could help in distinguishing between different prescriptions for the spin-dependent part of the interaction. Thus, by comparing with the reported baryon spectra obtained with parameters estimated from lattice QCD, one can challenge the precision of lattice calculations. The present work supports a coherent description of singly, doubly and triply heavy baryons with the same Cornell-like interacting potential. The possible experimental measurement of these states at LHCb is an incentive for this study.

hep-ph↗
arXiv2016

Maximal isospin few-body systems of nucleons and $Ξ$ hyperons

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 $NΞ$, $NNΞ$, $NΞΞ$ and $NNΞΞ$ systems with maximal isospin are bound. Since in these states the strong decay $NΞ\toΛΛ$ 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 $Ξ$'s in the maximal isospin channel could also be bound.

nucl-th↗
arXiv2016

$D^*$ $ΞN$ bound state in strange three-body systems

The recent update of the strangeness $-2$ ESC08c Nijmegen potential incorporating the NAGARA and KISO events predicts a $ΞN$ 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 $ΞN$ state is merged with $N$'s, $Λ$'s, $Σ's$ or $Ξ$'s, making use of the most recent updates of the two-body ESC08c Nijmegen potentials. We found that there appear stable states in the $ΞNN$ and $ΞΞN$ systems, the $ΞΛN$ and $ΞΣN$ systems being unbound.

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arXiv2016

Deeply bound $Ξ$ tribaryon

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 $ΞNN$ 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 $Ξd$ threshold. Since in lowest order, pure S$-$wave configuration, this system can not decay into the open $ΛΛN$ channel, its decay width is expected to be very small. We have also recalculated the $(I)J^P=(\frac{3}{2})\frac{1}{2}^+$ state and we have compared with results of quark-model based potentials.

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arXiv2015

J=3/2 charmed hypertriton

By solving exact three-body equations, we study the three-baryon system with charm $+1$. We look for possible bound states using baryon-baryon interactions obtained from a chiral constituent quark model. The smaller effect of the $Λ_c \leftrightarrow Σ_c$ conversion reverses the order of the $(I,J)=(0,1/2)$ and $(I,J)=(0,3/2)$ states, rather close on the strange sector. The diminishing of the kinetic energy due to the large reduced mass gives rise to a bound state in the $(I,J)=(0,3/2)$ channel. After correcting for Coulomb effects the binding energy would be between 140 and 715 keV.

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arXiv2015

Nonexistence of a $Λnn$ bound state

It has been recently suggested the existence of a neutral bound state of two neutrons and a $Λ$ hyperon, $^3_Λn$. 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 $Λnn$ bound state. For this purpose, we performed a full Faddeev calculation of the $Λnn$ system in the $(I,J^P)=(1,1/2^+)$ channel using the interactions derived from the constituent quark cluster model which describe well the two-body $NN$ and $NY$ data and the $Λnp$ hypertriton.

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arXiv2015

Light $Ξ$ hypernuclei

Arguments in favor of a light $ΞNN$ 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 $ΞNN$ state, being decoupled from the lowest $NΛΛ$ 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 attractive interaction of the two-body subsystems. We illustrate our discussion with a full-fledged Faddeev calculation of the $ΞNN$ system using simple potentials that mimic more elaborate interactions. We also make contact with different recent phenomenological interactions from the literature, like the ESC08 Nijmegen potential or quark-model based potentials.

hep-ph↗
arXiv2015

Heavy-baryon quark model picture from lattice QCD

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 heavy-quark static potentials derived using SU(3) lattice QCD. We make use of different numerical techniques for the three-body problem.

hep-ph↗
arXiv2015

Constituent-quark model description of triply heavy-baryon nonperturbative lattice QCD data

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 with a unique opportunity to confront model predictions with data. This comparison may also help to build a bridge between two difficult to reconcile lattice QCD results, namely, the lattice SU(3) QCD static three-quark potential and the recent results of nonperturbative lattice QCD for the triply heavy-baryon spectra.

hep-ph↗
arXiv2014

Pion-assisted charmed dibaryon candidate

The Lambda_c(2286)-N system is studied in a chiral constituent quark model and the resulting s-wave interaction is used in separable form within three-body models of the pi-Lambda_c-N system with quantum numbers (C,I,JP)=(+1,3/2,2+). Separable interactions are also used for the dominant p-wave pion-baryon channels dominated by the Delta(1232) and Sigma_c(2520) resonances. Faddeev equations with relativistic kinematics are solved on the real axis to search for bound states and in the complex plane to search for three-body resonances. Some of the models considered generate a very narrow bound state, requiring isospin violation for its strong decay. Other models lead to a narrow resonance (Gamma < 0.4 MeV) for resonance mass below the Sigma_c(2455)-N threshold. This would be the lowest-lying C=+1 dibaryon, with mass estimated approximately as 3370+/-15 MeV.

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arXiv2012

Heavy hadron spectroscopy: a quark model perspective

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 lowenergy hadron phenomenology without enforcing any particular model, to constrain its characteristics and learn about low-energy realization of the theory.

hep-ph↗
arXiv2012

Strangeness -2 hypertriton

We have solved for the first time the Faddeev equations for the bound state problem of the coupled $ΛΛN$--$ΞNN$ 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 $ΛΛN$ system alone is unbound. However, when the full coupling to $ΞNN$ is considered, the strangeness -2 three-baryon system with quantum numbers $(I,J^P)=(1/2,1/2^+)$ becomes bound, with a binding energy of about 0.5 MeV. This result is compatible with the non-existence of a stable $^3_Λ$H with isospin one.

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arXiv2010

The few body problem of the quark-model hadron structure

We discuss recent results of hadron spectroscopy and hadron-hadron interaction within a quark model framework. New experimental data could point to the important role played by higher order Fock space components on low-energy observables. Our aim is to obtain a coherent description of the low-energy hadron phenomenology to constrain QCD phenomenological models and try to learn about low-energy realizations of the theory. This long-range effort is based in adapting few-body techniques to study many-quark systems.

hep-ph↗
arXiv2010

Strangeness -2 two-baryon systems

We derive strangeness -2 baryon-baryon interactions from a chiral constituent quark model including the full set of scalar mesons. The model has been tuned in the strangeness 0 and -1 two-baryon systems, providing parameter free predictions for the strangeness -2 case. We calculate elastic and inelastic $NΞ$ and $ΛΛ$ cross sections which are consistent with the existing experimental data. We also calculate the two-body scattering lengths for the different spin-isospin channels.

hep-ph↗
arXiv2008

Towards an understanding of heavy baryon spectroscopy

The recent observation at CDF and D0 of $Σ_b$, $Σ^*_b$ and $Ξ_b$ 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 the search for new bottom baryons and their findings will help in constraining further the phenomenological models. We identify particular states whose masses may allow to discriminate between the dynamics for the light-quark pairs predicted by different phenomenological models. Within the same framework we also present results for charmed, doubly charmed, and doubly bottom baryons. Our results provide a restricted possible assignment of quantum numbers to recently reported charmed baryon states. Some of them are perfectly described by $D-$wave excitations with $J^P=5/2^+$, as the $Λ_c (2880)$, $Ξ_c(3055)$, and $Ξ_c(3123)$.

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