2,739 research outputs found
A potential including Heaviside function in 1+1 dimensional hydrodynamics by Landau
In 1+1 dimensional hydrodynamics originally proposed by Landau, we derive a
new potential and distribution function including Heaviside function and
investigate its mathematical and physical properties. Using the original
distribution derived by Landau, a distribution function found by Srivastava et
al., our distribution function, and the Gaussian distribution proposed by
Carruthers et al., we analyze the data of the rapidity distribution on charged
pions and K mesons at RHIC energies (sqrt(s_NN) = 62.4 GeV and 200 GeV). Three
distributions derived from the hydrodynamics show almost the same chi-squared
values provided the CERN MINUIT is used. We know that our calculations of
hadron's distribution do not strongly depend on the range of integration of
fluid rapidity, contrary to that of Srivastava et al. Finally the roles of the
Heaviside function in concrete analyses of data are investigated
Local thermalization in d + Au collisions
The extent of a locally equilibrated parton plasma in d + Au collisions at
sqrt(s_NN) = 200 GeV is investigated as a function of centrality in a
nonequilibrium-statistical framework. Based on a three-sources model,
analytical solutions of a relativistic diffusion equation are in precise
agreement with recent data for charged-particle pseudorapidity distributions.
The moving midrapidity source indicates the size of the local thermal
equilibrium region after hadronization. In central d + Au collisions it
contains 19% of the produced particles.Comment: 4 pages, 1 figure, Proc. QM2005 Budapes
BPS Saturation from Null Reduction
We show that any -dimensional strictly stationary, asymptotically
Minkowskian solution of a null reduction of -dimensional pure
gravity must saturate the BPS bound provided that the KK vector field can be
identified appropriately. We also argue that it is consistent with the field
equations.Comment: 10 page
Analyses of two and three pion Bose-Einstein Correlations using Coulomb wave functions
Using effective formulas we analyze the Bose-Einstein correlations (BEC) data
corrected for Coulomb interactions provided by STAR Collaboration and the
quasi-corrected data (raw data with acceptance correction etc) on 2\pi and 3\pi
BEC by using Coulomb wave function with coherence parameter included. The
corresponding magnitudes of the interaction regions turn out to be almost the
same: R_{Coul}(2\pi) \simeq \frac 32R_{Coul}(3\pi). R_{Coul} means the size of
interaction region obtained in terms of Coulomb wave function. This approximate
relation is also confirmed by the core-halo model. Moreover, the genuine 3rd
order term of BEC has also been investigated in this framework and its
magnitude has been estimated both in the fully corrected data and in the
quasi-corrected data.Comment: 12 pages, 5 figure
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