Browsing by Author "Elyazeed, Eman R. Abo"

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Chemical freeze-out in Hawking-Unruh radiation and quark-hadron transition
(AMER PHYSICAL SOC, 2015) Tawfik, Abdel Nasser; Yassin, Hayam; Elyazeed, Eman R. Abo
The proposed analogy between hadron production in high-energy collisions and Hawking-Unruh radiation process in the black holes shall be extended. This mechanism provides a theoretical basis for the freeze-out parameters, the temperature (T), and the baryon chemical potential (mu), characterizing the final state of particle production. The results from charged black holes, in which the electric charge is related to mu, are found comparable with the phenomenologically deduced parameters from the ratios of various particle species and the higher-order moments of net-proton multiplicity in thermal statistical models and Polyakov linear-sigma model. Furthermore, the resulting freeze-out condition < E > / < N > similar or equal to 1 GeV for average energy per particle is in good agreement with the hadronization process in the high-energy experiments. For the entropy density (s), the freeze-out condition s/T-3 similar or equal to 7 is found at mu less than or similar to 0.3 GeV. Then, due to the dependence of T on mu, the values of s/T-3 increase with increasing mu. In accordance with this observation, we found that the entropy density (s) remains constant with increasing mu. Thus, we conclude that almost no information is going lost through Hawking-Unruh radiation from charged black holes. It is worthwhile to highlight that the freeze-out temperature from charged black holes is determined independent on both freeze-out conditions.
Phenomenology of light- and strange-quark simultaneous production at high energies
(PLEIADES PUBLISHING INC, 2017-11) Elyazeed, Eman R. Abo; Yassin, Hayam; Tawfik, Abdel Nasser
This letter presents an extension of EPL116(2017) 62001 to light- and strange-quark nonequilibrium chemical phase-space occupancy factors (gamma(q,s)). The resulting damped trigonometric functionalities relating gamma(q,s) to the nucleon-nucleon center-of-mass energies (root s(NN)) looks very similar except different coefficients. The phenomenology of the resulting gamma(q,s) (root s(NN)) describes a rapid decrease at root s(NN) less than or similar to 7 GeV followed by a faster increase up to similar to 20 GeV. Then, both gamma(q,s) become nonsensitive to root s(NN). Although these differ from gamma(s) (root s(NN)) obtained at gamma(q) (root s(NN)) = 1, various particle ratios including K+/pi(+), K-/pi(-), Lambda/pi(-), (Lambda) over bar/pi(-), Xi(+)/pi(+), and Omega/pi(-), can well be reproduced, as well. We conclude that gamma(q,s) (root s(NN)) should be instead determined from fits of various particle yields and ratios but not merely from fits to the particle ratio k(+)/pi(+).
Strangeness production in high-energy collisions and Hawking-Unruh radiation
(WORLD SCIENTIFIC PUBL. CO. PTE LTD, 2017) Tawfik, Abdel Nasser; Yassin, Hayam; Elyazeed, Eman R. Abo
The assumption that the production of quark-antiquark pairs and their sequential string-breaking takes place, likely as a tunneling process, through the event horizon of the color confinement determines the freezeout temperature and gives a plausible interpretation for the thermal pattern of elementary and nucleus-nucleus collisions. When relating the black-hole electric charges to the baryon-chemical potentials, it was found that the phenomenologically deduced parameters from the ratios of various particle species and the higher-order moments of net-proton multiplicity in the statistical thermal models and Polyakov linear-sigma model agree well with the ones determined from the thermal radiation from charged black hole. Accordingly, the resulting freezeout conditions, such as normalized entropy density s/T-3 = 7 and average energy per particle < E > / < N > similar or equal to 1 GeV, are confirmed at finite chemical potentials as well. Furthermore, the problem of strangeness production in elementary collisions can be interpreted by thermal particle production from the Hawking-Unruh radiation. Consequently, the freezeout temperature depends on the quark masses. This leads to a deviation from full equilibrium and thus a suppression of the strangeness production in the elementary collisions. But in nucleus-nucleus collisions, an average temperature should be introduced in order to dilute the quark masses. This nearly removes the strangeness suppression. An extension to finite chemical potentials is introduced. The particle ratios of kaon-to-pion (K+/pi(+)), phi-to-kaon (phi/K-) and antilambda-to-pion ((Lambda) over bar/pi(-)) are determined from Hawking-Unruh radiation and compared with the thermal calculations and the measurements in different experiments. We conclude that these particle ratios can be reproduced, at least qualitatively, as Hawking-Unruh radiation at finite chemical potential. With increasing energy, both K+/pi(+) and phi/K- keep their maximum values at low SPS energies. But the further energy decrease rapidly reduces both ratios. For (Lambda) over bar / pi(-), there is an increase with increasing root sNN, i.e., no saturation is to be observed.