2,280 research outputs found
Comment on "Remark on the external-field method in QCD sum rules"
It is proved, that suggested by Jin modified formalism in the external-field
method in QCD sum rules exactly coincides with the formalism used before.
Therefore, unlike the claims of ref.1, this formalism cannot improve the
predictability and reliability of external-field sum rule calculations in
comparison with those, done by the standard approach.
PACS number(s): 12.38.Lg, 11.55.HxComment: 5 pages, RevTe
Quark distributions in QCD sum rules: unexpected features and paradoxes
Some very unusual features of the hadron structure functions, obtained in the
generalized QCD sum rules, like the surprisingly strong difference between
longitudinally and transversally polarized mesons structure functions
and the strong suppression of the gluon sea in longitudinally polarized
mesons are discussed. Also the problem of exact zero contribution of gluon
condensates to pion and longitudinally polarized meson quark
distributions is discussed.Comment: 9 pages, 5 fig
Weak interaction contribution to the inclusive hadron-hadron scattering cross sections at high
It is demonstrated that the strong power-like scaling violation in the
transverse momentum distribution of inclusive hadron production, observed by
CDF Collaboration in collisions at Tevatron is caused by
contribution of weak interaction. The contribution of weak interaction is
increasing with energy at high energies.Comment: Talk presented at Gribov-80 Memorial Workshop, Trieste, May 26-28,
2010 and International seminar Quarks-2010, Colomna, June 6-12, 2010, 6
pages, 3 figures, it is accounted the weak boson formfactor, caused by strong
interactio
Chiral effective theory of strong interactions
The review of chiral effective theory (CET) is given. CET is based on quantum
chromodynamics and describes the processes of strong interaction at low
energies. It is proved, that CET comes as a consequence of the spontaneous
violation of chiral symmetry in QCD - the appearance of chiral symmetry
violating vacuum condensates. The Goldstone theorem for the case of QCD is
proved and the existence of the octet of massless Goldstone bosons (pi, K, eta)
is demonstrated in the limit of massless u,d,s quarks (or the triplet of
massless pions in the limit m_u,m_d->0). It is shown, that the same phenomenon
- the appearance of quark condensate in QCD - which causes the Goldstone
bosons, results in appearance of violating chiral symmetry massive baryons. The
general form of CET Lagrangian is derived. Few examples of higher order
corrections to tree diagrams in CET are given. The Wess-Zumino term (of order
p^4 term in CET Lagrangian) is presented. Low energy sum rules are presented.
QCD and CET at finite temperature are discussed. In the framework of CET the
T^2 correction to quark condensate in QCD at finite temperature T is calculated
and the results of higher order temperature corrections are demonstrated. These
results indicate on phase transition in QCD at T \sim 150-200 MeV. The mixing
of current correlators in order T^2 is proved.Comment: 36 pages, 7 figure
Chiral phase transition in hadronic matter at non-zero baryon density
A qualitative analysis of the chiral phase transition in QCD at non--zero
baryon density is performed. It is assumed that at zero baryonic density,
, the temperature phase transition is of the second order and quark
condesate may be taken as order parameter of phase transition. It is
demonstrated, that the proportionality of baryon masses to quark condensate in
the power 1/3, is valid
in the wide interval of quark condensate values. By supposing, that such
specific dependence of baryon masses on quark condensate takes place up to
phase transition point, it is shown, that at finite baryon density the
phase transition becomes of the first order at the temperature
for . At temperatures
there is a mixed phase
consisting of the quark phase (stable) and the hadron phase (unstable). At the
temperature the system experiences a continuous
transition to the pure chirally symmetric phase.Comment: 9 pages, 6 figures, Invited talk at 13-th International Seminar
"Quarks-2004",Pushkinskie Gory, May 24-30, 2004, to be published in the
Proceedings. v2. References are correcte
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