Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userFinal State Interactions in Bose-Einstein Correlations
171
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We are presenting here the new formulae for Bose-Einstein correlations (BEC) which contain effects of final state interactions (FSI) of both strong (in $s$-wave) and electromagnetic origin. We demonstrate the importance of FSI in BEC by analysing data for $e^+e^-$ annihilation and for heavy collisions. The inclusion of FSI results in the practical elimination (at least in $e^+e^-$ data) of the so called degree of coherence parameter $lambda$ (which becomes equal unity) and the long range parameter $gamma$ (which is now equal zero).
rate research
Read More
Recently DELPHI Collaboration reported new data on Bose-Einstein correlations (BEC) measured in e+e- -> W^+W^- events. Apparently no enhancement has been observed. We have analyzed these data including final state interactions (FSI) of both Coulomb and strong (s-wave) origin and found that there is enhancement in BEC but it is overshadowed by the FSI which are extremely important for those events. We have found the following values for the size of the interaction range beta and the degree of coherence lambda: beta=0.87 +/- 0.31fm and lambda=1.19 +/- 0.48, respectively.
We applied an analytical formula for Bose-Einstein correlations (BEC) developed by us recently to high-energy heavy ion collisions, in particular to data on S+Pb$topi^+$-$pi^+$+X reaction at energy $200$ GeV/nucleon reported by the NA44 Collaboration. It takes into account both Coulomb and strong ($pi$-$pi$~s-wave; I=2) final state interactions (FSI). We have found that inclusion of the strong interaction in addition to Coulomb correction affects significantly the extracted parameters of the BEC like the source size $R$, the degree of coherence $lambda$ and the long-range correlation parameter $gamma$. In particular, the $lambda$ parameter of the BEC is increased by about 20%. Our results differ from those obtained in $e^+e^-$ annihilation in the following way: the $lambda$ parameter does not reach `chaotic limit and the $gamma$ parameter does not approach to zero.
We present an analytical formula for the Bose-Einstein correlations (BEC) which includes effects of both Coulomb and strong final stateinteractions (FSI). It was obtained by using Coulomb wave function together with the scattering partial wave amplitude of the strong interactions describing data on the $s$-wave phase shift. We have proved numerically that this method is equivalent to solving Schr{o}dinger equation with Coulomb and the $s$-wave strong interaction potentials. As an application we have analysed, using our formula which includes the degree of coherence and the long range correlation, the data for $e^+e^-$ annihilations. We have found that the degree of coherence present in our formula approaches approximately unity whereas the long range correlation parameter becomes approximately zero. These results suggest that the physical meanings of the fractional degree of coherence and the long range correlation observed in various other analyses can most probably be attributed to FSI.
We describe an attempt to numerically model Bose-Einstein correlations (BEC) from within, i.e., by using them as the most fundamental ingredient of a Monte Carlo event generator (MC) rather than considering them as a kind of (more or less important, depending on the actual situation) afterburner, which inevitably changes the original physical content of the MC code used to model multiparticle production process.
We show that the large corrections due to final state interactions (FSI) in the D^+to pi^-pi^+pi^+, D^+_sto pi^-pi^+pi^+, and D^+to K^-pi^+pi^+ decays can be accounted for by invoking scattering amplitudes in agreement with those derived from phase shifts studies. In this way, broad/overlapping resonances in S-waves are properly treated and the phase motions of the transition amplitudes are driven by the corresponding scattering matrix elements determined in many other experiments. This is an important step forward in resolving the puzzle of the FSI in these decays. We also discuss why the sigma and kappa resonances, hardly visible in scattering experiments, are much more prominent and clearly visible in these decays without destroying the agreement with the experimental pipi and Kpi low energy S-wave phase shifts.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
