Saturation in deep inelastic scattering (DIS) and deeply virtual Compton
scattering (DVCS) is associated with a phase transition between the partonic
gas, typical of moderate $x$ and $Q^2$, and partonic fluid appearing at
increasing $Q^2$ and decreasing Bjorken $x$. In the statistical interpretation
of DIS, the large-$x,(1-x)^n$ factor in the SF is associated with a statistical
distribution (perfect gas), while the low-$x$, Regge behaved factor
$x^{b(Q^2)}$ produces deviations from the perfect gas and ultimately leads to a
gas-liquid phase transition. In this paper we do not intend to propose another
parametrization of the structure function; instead we suggest a new insight
into the internal structure of the nucleon, as seen in DIS, and its connection
with that revealed in high-energy nucleons and heavy-ion collisions.
The induced axial current and the chiral anomaly are studied in the normal
phase of magnetized relativistic matter. A special attention is paid to the
role of the chiral shift parameter Delta, leading to a relative shift of the
longitudinal momenta in the dispersion relations of opposite chirality
fermions. In the Nambu-Jona-Lasinio model, it is shown directly from the form
of the gap equation that Delta necessarily exists in the normal phase in a
magnetic field. By making use of the gauge invariant point-splitting
regularization, we then show that the presence of Delta essentially modifies
the form of the axial current, but does not affect the conventional axial
anomaly relation. By recalculating the axial current with the proper-time
regularization, we conclude that the result is robust with respect to a
specific regularization scheme used.
The near-threshold 12C (0^+_2) resonance provides unique possibility for fast
helium burning in stars, as predicted by Hoyle to explain the observed
abundance of elements in the Universe. Properties of this resonance are
calculated within the framework of the alpha-cluster model whose two-body and
three-body effective potentials are tuned to describe the alpha - alpha
scattering data, the energies of the 0^+_1 and 0^+_2 states, and the
0^+_1-state root-mean-square radius. The extremely small width of the 0^+_2
state, the 0_2^+ to 0_1^+ monopole transition matrix element, and transition
radius are found in remarkable agreement with the experimental data. The
0^+_2-state structure is described as a system of three alpha-particles
oscillating between the ground-state-like configuration and the elongated chain
configuration whose probability exceeds 0.9.
We show that, by taking a bare mass spectrum with constant spacings for the
quark-antiquark propagators, which is subject to considerable mass shifts from
meson loops, one adequately describes a large variety of mesonic resonances,
from the light scalars to the b-bbar states. All our results indicate that a
harmonic-oscilator spectrum with universal frequency, in combination with
coupled-channel effects, does a much better job than the q-barq spectrum of the
funnel potential.
We study the equation of state (EOS) of nuclear matter as function of
density. We expand the energy per particle (E/A) of symmetric infinite nuclear
matter in powers of the density to take into account 2,3,. . .,N-body forces.
New EOS are proposed by fitting ground state properties of nuclear matter
(binding energy, compressibility and pressure) and assuming that at high
densities a second order phase transition to the Quark Gluon Plasma (QGP)
occurs. The latter phase transition is due to symmetry breaking at high density
from nuclear matter (locally color white) to the QGP (globally color white). In
the simplest implementation of a second order phase transition we calculate the
critical exponent ? by using Landau's theory of phase transition. We find ? =
3. Refining the properties of the EOS near the critical point gives ? = 5 in
agreement with experimental results. We also discuss some scenarios for the EOS
at finite temperatures.
We study the development of collectivity in the neutron-rich nuclei around
$N=40$, where experimental and theoretical evidences suggest a rapid shape
change from the spherical to the rotational regime, in analogy to what happens
at the {\it island of inversion} surrounding $^{31}$Na. Theoretical
calculations are performed within the interacting shell model framework in a
large valence space, based on a $^{48}$Ca core which encompasses the full $pf$
shell for the protons and the $0f_{5/2}$, $1p_{3/2}$, $1p_{1/2}$, $0g_{9/2}$
and $1d_{5/2}$ orbits for the neutrons. The effective interaction is based on a
G-matrix obtained from a realistic nucleon-nucleon potential whose monopole
part is corrected empirically to produce effective single particle energies
compatible with the experimental data. We find a good agreement between the
theoretical results and the available experimental data. We predict the onset
of deformation at different neutron numbers for the various isotopic chains.
The maximum collectivity occurs in the chromium isotopes, where the large
deformation regime starts already at $N=38$. The shell evolution responsible
for the observed shape changes is discussed in detail, in parallel to the
situation in the $N=20$ region.
We develop a systematic framework for the study of the initial collision
geometry fluctuations in relativistic heavy-ion collisions and investigate how
they evolve through different stages of the fireball history and translate into
final particle momentum anisotropies. We find in our event-by-event analysis
that only the few lowest momentum anisotropy parameters survive after the
hydrodynamical evolution of the system. The geometry of the produced medium is
found to be affected by the pre-equilibrium evolution of the medium and the
thermal smearing of the discretized event-by-event initial conditions, both of
which tend to smear out the spatial anisotropies. We find such effects to be
more prominent for higher moments than for lower moments. The correlations
between odd and even spatial anisotropy parameters during the pre-equilibrium
expansion are quantitatively studied and found to be small. Our study provides
a theoretical foundation for the understanding of initial state fluctuations
and the collective expansion dynamics in relativistic heavy-ion collisions.
We review recent progress in the understanding of low-energy baryon structure
by means of chiral perturbation theory. In particular, we discuss the
application of this formalism to the description of various properties such as
the baryon-octet magnetic moments, the electromagnetic structure of decuplet
resonances and the hyperon vector coupling $f_1(0)$. Moreover, we present the
results on the chiral extrapolation of recent lattice QCD results on the
lowest-lying baryon masses and we predict the corresponding baryonic
sigma-terms.
We study the meta-stable states in high temperature phase of QCD
characterised by nonzero expectation values for the imaginary part of the
Polyakov loop. We consider $N_f= 2, 3$ dynamical staggered quarks, and carry
out simulations at various values of the coupling $\beta$ to observe these
states. In particular, we find the value of the coupling ($\beta_m$) above
which the meta-stable states appear. The values of $\beta_m$ we get suggest
that these states can not be accessible even at LHC.
1002.3824wilson : In this paper Sedrakyan and Chubukov have finally resolved the long-standing issue about the origin of the pseudogap in cuprates. This study...
1005.5173renner : To clarify in response to the above comment, our main result is that quantum theory cannot be *extended*. We consider an extension to a the...
1005.5173peaches : I'm not sure that it's fair to say that this is is an extension of Bell's result in the general case because the main theorem relies on the ...
1005.4932ayvlasov : I am not quite realizing, if it is necessary to make some comments, because most arguments already have been raised by few different people ...