Parton recombination at all pTp_T

Hadron production at all $p_T$ in heavy-ion collisions in the framework of parton recombination is reviewed. It is shown that the recombination of thermal and shower partons dominates the hadron spectra in the intermediate $p_T$ region. In $d+Au$ collisions, the physics of particle production at any $\eta$ is basically the same as at $\eta=0$. The Cronin effect is described as a result of the final-state instead of the initial-state interaction. The suppression of $R_{CP}$ at high $\eta$ is due to the reduction of the soft parton density on the deuteron side, thus resulting in less pions produced by recombination, an explanation that requires no new physics. In $Au+Au$ collisions large $p/\pi$ ratio is obtained because the thermal partons can contribute to the formation of proton more than they do to the pion.Comment: 12 pages + 5 figures. Invited talk at Hard Probes 200

Resolutions of Several Puzzles at Intermediate pTp_T and Recent Developments in Correlation

Some of the puzzles on hadron production at intermediate $p_T$ found at RHIC are explained as natural consequences of parton recombination. In that framework for hadronization the correlation among hadrons produced in jets can be calculated. Some new results on both near-side and away-side jet structures are presented.Comment: 5 pages in LaTeX , 0 figures. Talk given at Quark Matter 200

High p_T Hadron Correlation and No Correlation

An overview of the correlation among high-p_T hadrons produced in heavy-ion collisions is presented. Emphasis is placed on the physical processes that can quantitatively account for the data on correlations in p_T, \eta and \phi on the near and far sides. Predictions are made on processes that have no observable correlations for hadrons produced at intermediate and higher p_T at RHIC and LHC.Comment: 8 pages including 14 figures. Talk given at Hard Probes 200

Comparison of Nuclear Suppression Effects on Meson Production at High p_T and p_L

The medium effect on the pion distribution at high $p_T$ in $AA$ collisions is compared to that of the pion distribution at high $p_L$ in $pA$ collisions. Both the suppression of the spectra and the energy losses of the measured pions are studied. Although the medium effect on $p_T$ is larger than on $p_L$, the difference is found surprisingly to be not as big as one would naively expect.Comment: 8 RevTex pages with 5 figure

Elliptic Flow arising from Ridges due to Semi-hard Scattering

Azimuthal anisotropy in heavy-ion collisions is studied by taking into account the ridges generated by semi-hard scattering of intermediate-momentum partons, which can be sensitive to the initial spatial configuration of the medium in non-central collisions. In a simple treatment of the problem where the recombination of only thermal partons is considered, analytical formulas can be derived that yield results in accord with the data on v_2 for p_T <1-2 GeV/c. Centrality dependence is described by a geometrical factor. Ridge phenomenology is used to determine the initial slopes of v_2 at low p_T for both pion and proton. For higher p_T, shower partons from high-p_T jets must be included, but they are not considered here.Comment: revised version with new title and expanded discussion, to be published in Phys. Lett.

Aplikasi Teori Teknik Kimia dalam Mencari Model Matematis Pengurangan Berat Tomat Selama Penyimpanan

This article is explained how to make chemical engineering concept more applicable and interesting to students through their experience in research project. The title of their project is “The evaporation rate of stored the water content of fruits and vegetables”. This research aimed to study some factors influencing the evaporation rate, to develop mathematical model describing the evaporation process of stored fruits’s and vegetables’s water content. The experiment was simple and easy. The students kept fruits and vegetables in a storage room and observed the changed in weight of them. Then, they processed data and made mathematical model to explain the behavior of weight loss during storage. During guiding students, faculty concerned with improving the competence of students. Lecturer took students recognize their learning style. By knowing learning style, students would learn more concepts easily. Students learned material through reading journals, textbooks and discussion with lecturer too. The understanding in theory to formulate mathematical model and communication skill could improved through discussion. Students managed to achieve the goal of their research. They could communicate their ideas well and appear confident at the final project seminar

Parton Distributions in the Valon Model

The parton distribution functions determined by CTEQ at low $Q^2$ are used as inputs to test the validity of the valon model. The valon distributions in a nucleon are first found to be nearly $Q$ independent. The parton distribution in a valon are shown to be consistent with being universal, independent of the valon type. The momentum fractions of the partons in the valon add up separately to one. These properties affirm the validity of the valon model. The various distributions are parameterized for convenient application of the model.Comment: 9 pages + 9 figures in ep

Correlations at intermediate pTp_T

Correlations among hadrons in jets produced in heavy-ion collisions are discussed in the framework of the recombination model. The basic correlation at the parton level is among the shower partons arising from kinematical constraint. The resultant correlation between hadrons at intermediate $p_T$ is amazingly rich in characteristics.Comment: 10 pages including 12 figures. Talk presented at the MIT Workshop on Correlations and Fluctuations in Relativistic Nuclear Collisions, April 200

Renormalization group approach to multiparticle density fluctuations

An iterative procedure is developed with the aim of constructing homogeneity rules for the distribution P(rho,delta) of the particle density rho at resolution scale delta. A single iteration step consists of a change in the normalization point of P(rho,delta) followed by a rescaling. Similar transformation rule is introduced for density fluctuations contaminated by Poisson noise. Application of the iterative procedure is given for the Ginzburg-Landau description of phase-transition from the quark-gluon plasma and for random cascading models.Comment: 11 pages REVTeX, 1 figure include