Raziskovanje/Research
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Dynamically generated resonances
versus genuine three-quark states
While the mass of the Roper resonance (N(1440)) is determined by
the dynamically generated state with the dominant
s-wave sigmaN-component, a genuine three-quark component with
one of the 1s quarks excited to the 2s orbit and the mass above ~1750~MeV
is needed to explain the properties of the resonance:
Phys. Rev. C 97, 035204 (2018),
arXiv:1709.09025,
see also Bled 2018 workshop,
arXiv:1812.02043.
On the other hand, the N(1440) counterpart in the P33 partial wave,
the Delta(1600) resonance, turns out to be a purely dynamically generated
resonance with the dominant Delta-pion component:
Phys. Rev. C 100, 035204 (2019), arXiv:1908.11750.
It is believed that the Lambda1405 is a perfect example of a dynamically
generated resonance since it lies below
the corresponding negative parity state in the non-strange sector.
We show however that it does contain - beside a nucleon-antikaon
component - a genuine three quark component.
The observed scattering amplitudes can be well reproduced by assuming
the three-quark configuration also for the other two resonances
in this partial wave.
Eur. Phys. J. A (2022) 58:116, arxiv:2201.01489.
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Electroproduction of mesons
and the role of the meson cloud
The pion cloud in the nucleon plays the crutial role
in electroproduction of the Delta resonance,
see
Eur.Phys.J. A26 (2005) 99,
arXiv:hep-ph/0409246,
Phys.Lett. B553 (2003) 51,
arXiv:hep-ph/0210014,
Phys.Lett. B373 (1996) 229,
arXiv:hep-ph/960137,
while the pion and the sigma fields play a significant role
in the Roper resonance:
Eur.Phys.J.A42 (2009) 185,
arXiv:0906.2066,
Eur.Phys.J.A38 (2008) 271,
arXiv:0708.3759,
Phys.Lett. B523 (2001) 273,
arXiv:hep-ph/0103171,
talk presented at EMI2001 in Osaka, Japan,
arXiv:hep-ph/0201020,
talk presented at
Bled2001 workshop,
arXiv:hep-ph/0111399,
talk presented at EEF70 workshop in Coimbra in 2013,
arXiv:1604.03289.
The meson cloud, in particular the eta meson, turns out to
be important in the case of the S11 wave resonances:
Eur. Phys. J. A 47 (2011) 61,
arXiv:1101.5527,
see also the talk at the
Workshop on Pion-Nucleon Partial-Wave Analysis
and the Interpretation of Baryon Resonances 23-27 May, 2011, Washington,
and
the contributed talk at the Hadron 2011 conference
arXiv:1109.0163.
The meson cloud contributes substantially also in the
case of the D-wave resonances:
Eur. Phys. J. A 49, 111 (2013),
arXiv:1306.333.
Photoproduction of eta mesons and kaons reveals important
information of the
P11, P13, P33 and S11 resonances:
Eur. Phys. J. A 52, 279 (2016),
arXiv:1604.01937.
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Baryons as Solitons in Chiral Quark Models
The solitons found in a version of the Nambu-Jona--Lasinio model with
non-local interactions between quarks turn out to be stable without
the chiral-circle constraint for the meson fields, which is traditionally
imposed in the Nambu-Jona--Lasinio model with local interactions.
See
Phys.Lett. B437 (1998) 24,
arXiv:hep-ph/9807261,
as well as:
Nucl.Phys. A703 (2002) 667,
arXiv:hep-ph/0107139,
Few Body Syst.Suppl. 14 (2003) 1,
arXiv:hep-ph/0212077,
Bled 1999 workshop,
arXiv:hep-ph/0107115,
Coimbra 1999 workshop,
arXiv:hep-ph/9910479.
Approximating chiral quark models with linear sigma-models
Nucl.Phys. A714 (2003) 575,
arXiv:hep-ph/0210200.
Confined Chiral Solitons in the Spectral Quark Model
Phys.Rev.D76 (2007) 014008,
arXiv:hep-ph/0610289.
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Structure of the Constituent Quark
Soliton-like solutions in chiral quark models and in the
linear sigma model
Phys.Lett. B393 (1997) 161,
arXiv:9610538
might be a good description the constituent quark.
Chiral meson exchange potentials between such objects
turn out to be similar to phenomenological potentials
used in constituent quark models.
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Baryon-baryon potential in the
constituent quark model
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na vrh
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