Statement of Interests of Research

Dr. Abdelnasser M. Tawfik

Brief Description

The current works of Abdelnasser M. Tawfik (Ph.D. Marburg, 1999) can be briefly characterized as the quantitative and the phenomenological studies of the possible phase transition to the Quark-Gluon Plasma in ultra-relativistic heavy ion collisions. Generally, my recent activities can be summarized in the following list:
  1. Ultrarelativistic Nuclear and Elementary High Energy Physics
  2. QCD Calculations (Inclusive Particle Spectra, Multijet-Event, Angular Distributions, etc.)
  3. QCD corrections and the effective Lagrangians.
  4. Deconfinement and chiral symmetry breaking phase transition.
  5. Correlation length near the phase transition.
  6. Multi-Particle Correlation (Scaling Power Laws, Dimensional Intermittent behavior, Bose-Einstein Correlation, Mono-Fractal, Self-Similarity, Fractal Dimensions, G-Moment, Factorial Cumulations, Erraticity, etc.)
  7. Inclusive Particle Production (Fragmentation)
  8. Structure of Particle-Jets in Hard Interacting Systems
  9. Multi Dimensional Spin-Lattice Calculations (Integrable Studies in frame of Potts, Ising, Liquid-Gas , Ginzburg-Landau Models, etc.)
  10. Modeling, Simulations and Detection Methods
  11. Automated Measuring Systems (Hard- and Software)
  12. Computational Physics (Software)

Detailed Description

My current research activities are primarily concerned with the different physical phenomena that appear when the structure of the Physical Vacuum during the interaction is changed. It is known in framework of the Quantum Field Theory that the different Physical Phenomena are not simply determined by the Equations Of Motion alone, but also by the nature of the entire physical Vacuum State. The same Quantum Field can we find in different Vacuum States, but possibly it displays different properties depending upon in which the Vacuum State is realized. As an example, the Glues can easily propagate because of the simplicity of their Electromagnetic Vacuum State. While Gluons cannot freely propagate beyond distances larger than the diameter of Nucleon (confinement state). Obviously, the reason for this is the Vacuum State of the Glue Field which is very complicated and show properties of opaqueness against the propagation of the Gluons. Under certain conditions (exotic high Temperature, Density, and Pressure, etc.), the structure of the Vacuum State itself can be changed. It is widely believed that the transitions of the structure of the Vacuum have been responsible for certain Phenomena occurred in the earliest stages of the evolution of our Universe. The Asymmetry of Matter-Antimatter and the Large Scale Structure of the Universe are two of these phenomena that are attributed to phase transitions of the Vacuum in the early evolution of the Universe.

Nowadays the Laboratory experiments at very energetic collisions between two atomic nuclei represent the best chance to study similar effects. Therefore, my work currently concentrates on the phenomenological and theoretical studies of the Nuclear Matter under extreme conditions (high Temperature and high Density). QCD predicts that above a critical Density or Temperature the Nuclear Matter dissolves into freely moved Quarks and Gluons. This new State of Matter is called the QGP. This phase transition is believed to be caused by a structural change in the QCD Vacuum State which allows the Quarks and the Gluons to freely propagate over large distances, even beyond the Nucleon's Diameter (deconfinement state). In the last few years, the QCD phase transition increasingly represents one of my preponderant research activities. It is known that for mq=0 the deconfinement phase transition is to be represented by the free energy of static quarks. For infinite mq the phase transition is simply resulted by of the chiral symmetry breaking restoration. Between these two extreme boundaries there is our real world. The correlation length beneath the critical point and the relations between these two phase transitions represent another activity.

My actual activities are deeply involved with the theoretical studies regularized with the phase transition to the state of QGP, on the two-dimensional Spin-Lattice and involved with the theories of the Multi-Particle correlation. The primitive goal of these Spin-Lattice calculations is to test, even numerically, whether the foreknown Phase Transitions (hadron => QGP => hadron), can be experimentally recreated. In other words, to check and to verify the different suggested signatures for QGP, if this new State of Matter is indeed being produced in an interacting system. For works which I performed during my Promotion at the Marburg University, I have been constrained to use the Emulsion Detector, which, on the one hand, has very high angular and local resolution. But, on the other hand, neither the produced particles can be identified nor their four impulses can be directly estimated. For this kind of detector, there was a very limited number of signatures for the predicted QGP. During my Ph.D.-work, I have extended the ability of the emulsion detector to be used for nearly determination of the four impulses and to identify the produced particles. Such a way, I could use it to study the quantitative effects of the Bose-Einstein Correlation on the calculated intermittent behavior. Also I was able to study the dynamics of the interacting systems, since the system evolution now could be estimated by using these experimental methods. The new experiments within the physics program of RHIC, where from 600 to 1200 charged pions per unit-rapidity are expected, will enable us to determine not only the single particle spectra and then the two-particle Bose-Einstein correlations but also the higher-order Bose-Einstein correlation functions, which are necessary to distinguish between fully chaotic and partially coherent particles sources.

Experimentally, one has to check for the suggested signatures for QGP and has to compare the experimental results with the numerical ones, in which different phase transitions can be easily simulated, for instance, phase transition from Ferro- to Para-Magnetism as in Ising-Model or from Liquid to Gas as in the Liquid-Gas-Model or from non-coherent to coherent light (Laser) as in Ginzburg-Landau-Model.

I am presently working at the Institute for Plasmaforschung, Stuttgart University, Germany. Simultaneously I am a member of many physical societies and of the CERN-EMU01 collaboration, whose primary goal is to accurately measure the characters (Rapidity and Multiplicity) of a wide range of interacting systems (from O to Pb) over a wide range of energies (from 3,7 to 200 GeV/nucleon).

I can highly recommend the publications by the CERN-EMU01 collaboration and by myself and those on the topics of Bose-Einstein Correlation, Intermittent Behavior, Spin-Lattice Models, Fragmentation, Phase Transition, Automatic Measuring Systems.