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1.
We consider a quark model based on QCD scale anomaly in which the quarks move in the field of an effective glueball field.
Hadrons correspond to solitonic bags of higher energy density in a nonperturbative sea of condensed gluons. We calculate the
static properties of nucleon in this model and find that the nucleon mass is far too large (2.4–4 GeV) and the proton charge
radius (0.37–0.54 fm) is low. The proton gyromagnetic ratio and gA/gv are in reasonable agreement with the experimental numbers. 相似文献
2.
T. Schäfer 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):403-408
We review many-body calculations of the equation of state of dilute neutron matter in the context of effective-field theories
of the nucleon-nucleon interaction. 相似文献
3.
An empirical mass formula is tested for the basic fermion sequences of charged quarks and leptons. This relation is a generalization
of Barut’s mass formula for the lepton sequence (e, μ, τ......). It is found that successful mass extrapolation to the third and possibly to other higher generations (N>2) can be obtained with the first and second generation masses as inputs, which predicts the top quark massm
t to be around 20 GeV. This also leads to the mass ratios between members of two different sequences (i) and (i′) corresponding to the same higher generations (N>2). 相似文献
4.
S.?Terranova D.?M.?Zhou A.?BonaseraEmail author 《The European Physical Journal A - Hadrons and Nuclei》2005,26(3):333-337
We show that large fluctuations of D-mesons kinetic-energy (or momentum) distributions might be a signature of a phase transition to the Quark-Gluon Plasma (QGP).
In particular, a jump in the variance of the momenta or kinetic energy, as a function of a control parameter (temperature
or Fermi energy at finite baryon densities) might be a signature for a first-order phase transition to the QGP. This behavior
is completely consistent with the order parameter defined for a system of interacting quarks both at zero temperature (and
finite baryon densities) or at finite temperatures which shows a jump in correspondence with a first-order phase transition
to the QGP. The J/Ψ displays exactly the same behavior of the order parameter and of the variance of the D-mesons. We discuss implications for relativistic heavy-ion collisions within the framework of a transport model and possible
hints for experimental search. 相似文献
5.
M.?M.?H.?El-Gogary A.?Y.?EllithiEmail author M.?Kh.?Hegab A.?A.?Mohamed 《The European Physical Journal A - Hadrons and Nuclei》2005,24(1):137-147
In the framework of the Glauber multiple-scattering theory, the elastic collisions of proton-proton (pp) at the center-of-mass energies
= 23.5, 30.7, 44.7, and 52.8 GeV and alpha-proton (p) at
= 88 and 89 GeV are analyzed by considering the quark structure of their constituents. The differential cross-section containing the full multiple-scattering series between their quarks is calculated using Gaussian forms for the quark density and quark-quark (QQ) scattering amplitudes. The results obtained from the quark model and the conventional nucleon model are compared with the experimental data. The comparison shows that the nucleon model reproduces the experimental data more satisfactorily than the quark model, and both approaches have limited success in describing the data at such energies. The agreement with the experimental data is improved by the inclusion of the phase variation. 相似文献
6.
G. A. Miller 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):578-584
The discovery more than twenty years ago, by the EMC Collaboration, that the deep-inelastic-scattering DIS structure functions
are influenced by the nuclear environment stunned the nuclear physics community and brought quarks and gluons into the field
with great impact. A great length of time has passed, but despite a semi-infinite number of papers on the subject, there is
no explanation that is universally accepted. Many models (related in one way or another to QCD) have been successful in reproducing
data for deep inelastic scattering on nuclear targets, but fewer have described both the DIS and nuclear Drell-Yan experiments.
Although there are some positive indications, no model has been used to predict correctly and unambiguously new independent
phenomena. We review the history and discuss the best experimental prospects for future discovery. 相似文献
7.
The Geant4 CHIPS model simulates both decay and nuclear capture of negative muons. In hadron level models the muon is captured
by a proton, p(μ,νμ)n , and the neutron transfers to the nucleus only 5MeV, which is not enough to split a nucleon from the nucleus, while the
measured spectra of emitted nucleons reach 80MeV. In CHIPS, which considers asymptotically free quark-partons, the muon can
be captured by a quark, u(μ,νμ)d , and transfers 52MeV to the nucleus. This capture mechanism fits the main part of the nucleon spectra, while the high-energy
part of the spectra is not fitted. A precise fit of the high-energy part of the nucleon spectra can be made if the muon decay
μ → dˉνμ is taken into account. 相似文献
8.
D. d'Enterria 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):816-823
We present a summary of the physics of gluon saturation and non-linear QCD evolution at small values of the parton momentum
fraction x in the proton and nucleus in the context of recent experimental results at HERA and RHIC. The rich physics potential of low-x studies at the LHC, especially in the forward region, is discussed and some benchmark measurements in pp, pA and AA collisions are introduced. 相似文献
9.
N. Jachowicz G. C. McLaughlin 《The European Physical Journal A - Hadrons and Nuclei》2006,29(1):43-47
We argue that isotropization and, consequently, thermalization of the system of gluons and quarks produced in an ultrarelativistic
heavy-ion collision does not follow from Feynman diagram analysis to any order in the coupling constant. We conclude that
the apparent thermalization of quarks and gluons, leading to success of perfect fluid hydrodynamics in describing heavy-ion
collisions at RHIC, can only be attributed to the non-perturbative QCD effects not captured by Feynman diagrams. We proceed
by modeling these non-pertrubative thermalization effects using viscous hydrodynamics. We point out that matching Color Glass
Condensate inital conditions with viscous hydrodynamics leads to a continuous evolution of all the components of the energy-momentum
tensor and, unlike the case of ideal hydrodynamics, does not give rise to a discontinuity in the longitudinal pressure. An
important consequence of such a matching is a relationship between the thermalization time and shear viscosity: we observe
that small viscosity leads to short thermalization time. 相似文献
10.
T. Hirano 《The European Physical Journal A - Hadrons and Nuclei》2006,29(1):19-22
We can establish a new picture, the perfect fluid sQGP core and the dissipative hadronic corona, of the space-time evolution
of produced matter in relativistic heavy-ion collisions at RHIC. It is also shown that the picture works well also in the
forward rapidity region through an analysis based on a new class of the hydro-kinetic model and that this is a manifestation
of the rapid increase of the entropy density in the vicinity of QCD critical temperature, namely, deconfinement. 相似文献