Correlations in the hadronization process

Pions cannot be fully described as simple $q\bar q$ systems. They have a very small mass and may appear as a kind of Goldstone particles. It is demonstrated how this is expected to give correlations in flavour andp _⊥ in the string model hadronization process. Improved agreement with experimental data is obtained, in particular for η′, η production and π⁺π^? mass correlations.     

Sudden hadronization in relativistic nuclear collisions

We formulate and study a mechanical instability criterion for sudden hadronization of dense matter fireballs formed in 158A GeV Pb-Pb collisions. Considering properties of quark-gluon matter and hadron gas we obtain the phase boundary between these two phases and demonstrate that the required deep quark-gluon-plasma supercooling prior to sudden hadronization has occurred.     

Kaon and antikaon properties in cold nuclear medium

We present results of a self-consistent calculation for the kaon and antikaon spectral functions in cold nuclear matter, using as input the kaon-nucleon and antikaon-nucleon scattering amplitudes of the vacuum. We investigate the effect of in-medium pion dressing on the antikaon-nucleon scattering amplitudes and antikaon spectral function. We find the influence of pion dressing to be minor on the antikaon spectral function and limited on the hyperon resonances causing only a small additional broadening. An exception is the Σ(1690). At nuclear saturation density an attractive mass shift of about 20 MeV and width of about 130 MeV is obtained. The kaon shows a repulsive mass increase of 36 MeV and a small width of the quasiparticle peak at saturation density.     

The effect of hadronic rindler horizon on hadronization process

In this study by extending the recent suggested mechanisms to hadronization processes, the information loss for QCD matter in hadronic Rindler horizon is found. We notice that for all finite values of quark and gluon energies, all information from all hadronization processes experiences some degree of loss. Then the effect of hedonic Rindler horizon on three jet cross section is explored. It is found that the three jet cross section is rising at y_cut =?0.0002 exhibits a turn-over at moderate value of y_cut =?0.01 and then rapidly decreases as y_cut increases. This model is consistent with OPAL data. Finally, different channels for producing Higgs boson near hadronic Rindler horizon are studied. It is shown that the cross section of Higgs boson produced via gluon fusion and quark interaction near a single Hadronic Rindler Horizon is much larger for higher center of mass energies. This is because an increase in the energy of hadronic Rindler horizon raises the temperature, thus intensifying the thermal radiation of QCD matter.     

Double-hadron leptoproduction in the nuclear medium

The first measurements of double-hadron production in deep-inelastic scattering within the nuclear medium were made with the HERMES spectrometer at DESY HERA using a 27.6 GeV positron beam. By comparing data for deuterium, nitrogen, krypton, and xenon nuclei, the influence of the nuclear medium on the ratio of double-hadron to single-hadron yields was investigated. Nuclear effects on the additional hadron are clearly observed, but with little or no difference among nitrogen, krypton, or xenon, and with smaller magnitude than effects seen on previously measured single-hadron multiplicities. The data are compared with models based on partonic energy loss or prehadronic scattering and with a model based on a purely absorptive treatment of the final-state interactions. Thus, the double-hadron ratio provides an additional tool for studying modifications of hadronization in nuclear matter.     

Space-time evolution of hadronization

Beside its intrinsic interest for the insights it can give into color confinement, knowledge of the space-time evolution of hadronization is very important for correctly interpreting jet-quenching data in heavy-ion collisions and extracting the properties of the produced medium. On the experimental side, the cleanest environment to study the space-time evolution of hadronization is semi-inclusive deeply inelastic scattering on nuclear targets. On the theoretical side, two frameworks are presently competing to explain the observed attenuation of hadron production: quark energy loss (with hadron formation outside the nucleus) and nuclear absorption (with hadronization starting inside the nucleus). I will discuss recent observables and ideas which will help to distinguish these two mechanisms and to measure the time scales of the hadronization process. PACS 25.30.-c; 25.75.-q; 24.85.+p; 13.87.Fh     

Charmed hadrons in nuclear medium

We study the properties of charmed hadrons in dense matter within a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We analyze the behaviour in this dense environment of dynamically-generated baryonic resonances as well as the open-charm meson spectral functions. We discuss the implications of the in-medium properties of open-charm mesons on the DsO(2317) and the predicted X(3700) scalar resonances.     

Multiscaling in the hadronization in high energy collisions

We study the multiscaling in the fluctuations of multiparticle distributions at small scales. Similarly to the multiscaling effect, recently found in multifractal models, we analyse the dependence of the strength of the fluctuations on the low density cut-off in the cascade. The effect changes the scaling behaviour and leads to stronger dependence of the scaled factorial moments on the resolution than the power law. This could be an explanation of the behaviour observed recently in the experimental 3-dimensional data on the scaled factorial moments. The multiscaling analysis allows to restore the universality in the processes with different cut-offs and could be used in the analysis of the experimental data.     

On the size of nucleons in the nuclear medium

The change of nucleon size due to the nuclear environment is investigated via the y-scaling property of quasi-elastic electron-nucleus scattering. We find a low upper limit, 3–6%, for the increase of the radius.     

Finite size nucleonic effects in the nuclear medium

The finite size effects of nucleons inside a nucleus is investigated. This new approach is entirely different from Hagedorn’s volume correction method and is more rigorous. The size of the nucleon is varied and the magnitude of the hard-core potential is extracted by minimising the energy with respect to the nuclear radius.     

Geometric interpretation of hadronization model

A hadronization model termed as geometric dielectric confinement model is described. The model describes the charmed meson decays quite successfully. In the model we assume that the non-abelian gauge field describing the colour force simulates the effect of a medium having space-dependent dielectric constant. The quarks produced in weak decays move in the dielectric medium such that they are free in limited region of space (r⋍0) and cannot appear as asymptotic states resulting in hadronization. It is found that the dielectric medium resembles anti-desitter microuniverse and the quarks behave essentially as free particles damped by gaussian distribution. The model reproduces from a single Lagrangian the quark motion as well as the form of dielectric function.     

On phase transitions in cold nuclear matter

Real conditions for the formation of cold subhadronic matter are considered with allowance for nontrivial properties of the QCD vacuum. It is shown that a steady state of this matter is attainable, if at all, only in the case where dynamical (massive) quarks exist as rather stable quasiparticles. This state may consist of both a degenerate nearly perfect gas of these particles and a degenerate gas of current quarks in the interior of some (compact) neutron stars. In the latter case, both phases should coexist, and the first phase should occupy a certain space between the second phase and (normal) hadron matter occurring at the periphery of the star.     

Search for cold nuclear fusion in palladium-deuteride

We searched for protons generated in cold D fusion reactions in Pd cathodes doped electrolytically with D. The applied experimental technique allowed the detection of proton production rates exceeding 0.074 s^–1 per cm³ cathode material (or 3.1·10^–24 s^–1 per D pair). Our results do not confirm fusion rates such like those recently reported.     

Exotica in dense and cold nuclear matter

A method for creating and investigating, under laboratory conditions, droplets of superdense cold matter is proposed, neutron stars being the closest analog of this kind of matter in nature. Arguments in support of the statement that an implementation of respective experiments is possible are presented, and the mechanism of kinematical cooling of the droplets in question is clarified. Various trigger types are proposed for performing searches for various exotic multiquark states in cold superdense matter.     

Ultraslow optical solitons in a cold four-state medium

We show the formation of ultraslow optical solitons in a lifetime broadened four-state atomic medium under Raman excitation. With appropriate conditions we demonstrate, both analytically and numerically, that both bright and dark ultraslow optical solitons can occur in such a highly resonant medium with remarkable propagation characteristics. This work may open other research opportunities in condensed matter and may result in a substantial impact on technology.