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Title: Heavy baryons and their exotics from instantons in holographic QCD

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Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 95; Journal Issue: 11; Related Information: CHORUS Timestamp: 2017-06-23 22:13:14; Journal ID: ISSN 2470-0010
American Physical Society
Country of Publication:
United States

Citation Formats

Liu, Yizhuang, and Zahed, Ismail. Heavy baryons and their exotics from instantons in holographic QCD. United States: N. p., 2017. Web. doi:10.1103/PhysRevD.95.116012.
Liu, Yizhuang, & Zahed, Ismail. Heavy baryons and their exotics from instantons in holographic QCD. United States. doi:10.1103/PhysRevD.95.116012.
Liu, Yizhuang, and Zahed, Ismail. Fri . "Heavy baryons and their exotics from instantons in holographic QCD". United States. doi:10.1103/PhysRevD.95.116012.
title = {Heavy baryons and their exotics from instantons in holographic QCD},
author = {Liu, Yizhuang and Zahed, Ismail},
abstractNote = {},
doi = {10.1103/PhysRevD.95.116012},
journal = {Physical Review D},
number = 11,
volume = 95,
place = {United States},
year = {Fri Jun 23 00:00:00 EDT 2017},
month = {Fri Jun 23 00:00:00 EDT 2017}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on June 23, 2018
Publisher's Accepted Manuscript

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  • A hadron's multiquark content reflects itself in the quark composition of the interpolator with which it has maximal overlap. The AdS/CFT dictionary translates the anomalous dimension of this interpolator into a mass correction for the corresponding dual mode. Hence such bulk-mass corrections can carry specific information on multiquark correlations. Two prominent examples are studied by implementing this robust and universal holographic mechanism into AdS/QCD gravity duals. In the baryon sector bulk-mass corrections are used to describe systematic good (i.e. maximally attractive) diquark effects. The baryon sizes are predicted to decrease with increasing good-diquark content, and the masses of all 48more » observed light-quark baryon states are reproduced with unprecedented accuracy. Our approach further provides the first holographic description of a dominant tetraquark component in the lowest-lying scalar mesons. The tetraquark ground state emerges naturally as the lightest scalar nonet whereas higher excitations become heavier than their quark--antiquark counterparts and are thus likely to dissolve into the multiparticle continuum.« less
  • In the holographic model of QCD, {theta} dependence sharply changes at the point of confinement-deconfinement phase transition. In large N QCD such a change in {theta} behavior can be related to the breakdown of the instanton expansion at some critical temperature T{sub c}. Associating this temperature with confinement-deconfinement phase transition leads to the description of the latter in terms of dissociation of instantons into the fractionally charged instanton quarks. To elucidate this picture, we introduce the nonvanishing chiral condensate in the deconfining phase and assume a specific Lagrangian for the {eta}{sup '} field in the confining phase. In the resultingmore » picture the high-temperature phase of the theory consists of the dilute gas of instantons, while the low-temperature phase is described in terms of freely moving fractional instanton quarks.« less
  • Exotic hadrons with heavy quarks can confirm in the same multiquark system that the qq-bar interaction is much stronger than the qq interaction and produces color structures totally different from those of normal hadrons. Unusual heavy tetraquark structure may explain unusual properties of newly discovered mesons like the X(3872). Both charged and neutral B decays produce this narrow neutral resonant state that decays to both J/{psi}{rho} and J/{psi}{omega}, while no charged resonances in the same multiplet are found. This suggests that the X is an isoscalar resonance whose production conserves isospin, while isospin is violated only in the decay bymore » an electromagnetic interaction allowing the isospin-forbidden J/{psi}{rho} decay. New data for X production in B decays provide a separation between production and decay, sharpen several experimental puzzles and impose serious constraints on all models. A proposed isoscalar tetraquark model agrees with all present data, conserves isospin in its production and breaks isospin only in an electromagnetic X(3872)J/{psi}{rho}{sup o} decay. The narrow X decay width results from the tiny phase space available for the J/{psi}{omega} decay and enables competition with the electromagnetic isospin-forbidden J/{psi}{rho} decay which has much larger phase space. Experimental tests are proposed for this isospin production invariance.« less
  • We use QCD sum rule approach to calculate the masses of the ground-state {lambda}{sub Q} and {sigma}{sub Q}{sup (*)} baryons. Contributions of the operators up to dimension six are included in operator product expansion. The resulting heavy baryonic masses from the calculations are m{sub {lambda}{sub b}}=5.69{+-}0.13 GeV, and m{sub {lambda}{sub c}}=2.31{+-}0.19 GeV for {lambda}{sub Q}; m{sub {sigma}{sub b}}=5.73{+-}0.21 GeV, m{sub {sigma}{sub b}}{sub *}=5.81{+-}0.19 GeV, m{sub {sigma}{sub c}}=2.40{+-}0.31 GeV and m{sub {sigma}{sub c}}{sub *}=2.56{+-}0.24 GeV for {sigma}{sub Q}{sup (*)}, respectively, which are in good agreement with the experimental values.
  • We extract directly the charmed and bottom heavy-baryons (spin 1/2 and 3/2) masssplittings due to SU(3) breaking using double ratios of QCD spectral sum rules (QSSR) in full QCD. We deduce M{sub {Omega}{sub b}} = 6078.5(27.4) MeV which agrees with the recent CDF data but disagrees by 2.4{sigma} with the one from D0. Predictions of the {Xi}{sub Q}' and of the spectra of spin 3/2 baryons containing one or two strange quark are given in Table 1. Predictions of the hyperfine splittings {Omega}{sub Q}*-{Omega}{sub Q} and {Xi}{sub Q}*-{Xi}{sub Q} are also given in Table 2.