Scalar-quark systems and chimera hadrons in SU(3){sub c} lattice QCD

Journal Article · Fri Jun 01 04:00:00 EDT 2007 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.75.114503· OSTI ID:20929560

Iida, H; Takahashi, T T ^[1]; Suganuma, H ^[2]

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1. Yukawa Institute for Theoretical Physics, Kyoto University, Sakyo, Kyoto 606-8502 (Japan)
2. Department of Physics, Kyoto University, Graduate School of Science, Sakyo, Kyoto 606-8502 (Japan)

In terms of mass generation in the strong interaction without chiral symmetry breaking, we perform the first study for light scalar-quarks {phi} (colored scalar particles with 3{sub c} or idealized diquarks) and their color-singlet hadronic states using quenched SU(3){sub c} lattice QCD with {beta}=5.70 (i.e., a{approx_equal}0.18 fm) and lattice size 16{sup 3}x32. We investigate ''scalar-quark mesons'' {phi}{sup {dagger}}{phi} and ''scalar-quark baryons'' {phi}{phi}{phi} as the bound states of scalar-quarks {phi}. We also investigate the color-singlet bound states of scalar-quarks {phi} and quarks {psi}, i.e., {phi}{sup {dagger}}{psi}, {psi}{psi}{phi}, and {phi}{phi}{psi}, which we name ''chimera hadrons.'' All the new-type hadrons including {phi} are found to have a large mass even for zero bare scalar-quark mass m{sub {phi}}=0 at a{sup -1}{approx_equal}1 GeV. We find a ''constituent scalar-quark/quark picture'' for both scalar-quark hadrons and chimera hadrons. Namely, the mass of the new-type hadron composed of m {phi}'s and n {psi}'s, M{sub m{phi}}{sub +n{psi}}, approximately satisfies M{sub m{phi}}{sub +n{psi}}{approx_equal}mM{sub {phi}}+nM{sub {psi}}, where M{sub {phi}} and M{sub {psi}} are the constituent scalar-quark and quark masses, respectively. We estimate the constituent scalar-quark mass M{sub {phi}} for m{sub {phi}}=0 at a{sup -1}{approx_equal}1 GeV as M{sub {phi}}{approx_equal}1.5-1.6 GeV, which is much larger than the constituent quark mass M{sub {psi}}{approx_equal}400 MeV in the chiral limit. Thus, scalar quarks acquire a large mass due to large quantum corrections by gluons in the systems including scalar quarks. Together with other evidences of mass generation of glueballs and charmonia, we conjecture that all colored particles generally acquire a large effective mass due to dressed gluon effects. In addition, the large mass generation of pointlike colored scalar particles indicates that plausible diquarks used in effective hadron models cannot be described as the pointlike particles and should have a much larger size than a{approx_equal}0.2 fm.

• OSTI ID: 20929560
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 11 Vol. 75; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BOUND STATE
CHIRAL SYMMETRY
CHIRALITY
COLOR MODEL
EFFECTIVE MASS
GEV RANGE 01-10
GLUEBALLS
GLUONS
LATTICE FIELD THEORY
MEV RANGE 100-1000
PHI MESONS
QUANTUM CHROMODYNAMICS
QUARKS
STRONG INTERACTIONS
SU-3 GROUPS
SYMMETRY BREAKING