Speaker
Prof.
Vladimir Kopeliovich
(INR of RAS)
Description
The role of rescaling (expansion or squeezing) of quantized skyrmions [1,2] is
studied for the spectrum of baryons
beginning with nucleon and $\Delta(1232)$, and with flavors
strangeness, charm or beauty. The expansion of skyrmions due to the centrifugal forces has influence on
the masses of baryons without flavor ($N$ and especially $\Delta$); this effect leads to correction of the
well known results by Adkins, Nappi, Witten, and demands certain revision
of the fit of the model, proposed in [3,4]. In the case of chiral symmetry \cite{anw} analytical treatment
of the effect confirms results of numerical computations.
The rescaling of skyrmions has small influence on the spectrum
of strange baryons, it is more important for the case of charm, and crucial for baryons with beauty
quantum number, where strong squeezing takes place [5]. Two competing tendencies are clearly observed:
expansion of skyrmions when isospin (or spin) increases,
and squeezing with increasing mass of the flavor.
For the case of beauty baryon $\Lambda_b$ satisfactory agreement with data
can be reached for the value $r_b= F_B/F_\pi \simeq 2.6 $, for the case of $\Sigma_b$ there
should be $r_b\sim 2$, so for the beauty flavor the method seems to be not quite satisfactory
because of certain intrinsic discrepances. Some pentaquark states with hidden strangeness,
charm or beauty are considered as well [5].
[1] T.H.R.~Skyrme. A nonlinear field theory. Proc.R.Soc. London, A260 (1961) 127;
T.H.R.~Skyrme. A Unified Field Theory of Mesons and Baryons. Nucl.Phys. 31 (1962) 556
[2] E.~Witten.
Global Aspects of Current Algebra. Nucl.Phys. B223 (1983) 422;
Current Algebra, Baryons, and Quark Confinement. ibid B223 (1983) 433
[3] G.~Adkins, C.~Nappi, and E.~Witten.
Static Properties of Nucleons in the Skyrme Model. Nucl.Phys. B228 (1983) 552
[4] G.~Adkins and C.~Nappi.
The Skyrme Model with Pion Masses. Nucl.Phys. B233 (1984) 109
5. Vladimir B.~Kopeliovich and Irina K.~Potashnikova. Rescaling of quantized skyrmions: from nucleon to baryons with heavy flavor.
e-Print: arXiv:1703.04373 [hep-th]
Primary author
Prof.
Vladimir Kopeliovich
(INR of RAS)
