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Register a new userFinal state interactions for Bose-Einstein correlations in S+Pb $to$ $pi^+$$pi^+$ +X reaction at energy 200GeV/nucleon
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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.
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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).
We present a model for the decay $D^+to K^-pi^+pi^+$. The weak interaction part of this reaction is described using the effective weak Hamiltonian in the factorisation approach. Hadronic final state interactions are taken into account through the $Kpi$ scalar and vector form factors fulfilling analyticity, unitarity and chiral symmetry constraints. Allowing for a global phase difference between the $S$ and $P$ waves of $-65^circ$, the Dalitz plot of the $D^+to K^-pi^+pi^+$ decay, the $Kpi$ invariant mass spectra and the total branching ratio due to $S$-wave interactions are well reproduced.
We revisit the coupled channel $Kbar{K}$ interactions and dynamically generate the resonances $f_0(980)$ and $a_0(980)$ within both the isospin and the physical bases. The $f_0(980)-a_0(980)$ mixing effects are generated in the scattering amplitudes of the coupled channels with the physical basis, which exploits the important role of the $Kbar{K}$ channel in the dynamical nature of these resonances. With the scattering amplitudes obtained, we investigate the $f_0(980)$ and $a_0(980)$ contributions to the $J/psito gammaetapi^0$, $J/psito gammapi^+pi^-$ and $J/psito gammapi^0pi^0$ radiative decays through the final-state interactions. We obtain the corresponding branching fractions $Br(J/psito gamma a_0(980) to gammaetapi^0) = (0.47pm0.05) times 10^{-7}$, $Br(J/psito gamma f_0(980) to gammapi^+pi^-) = 0.37 times 10^{-7} - 1.98 times 10^{-6}$, $Br(J/psito gamma f_0(980) to gammapi^0pi^0) = 0.18 times 10^{-7} - 9.92 times 10^{-7}$, and predict $Br(J/psito gamma a_0(980)) = 1.72 times 10^{-8} - 3.07times 10^{-7}$ and $Br(J/psito gamma f_0(980)) = 1.86 times 10^{-8} - 1.89times 10^{-5}$. These fractions are within the upper limits of the experimental measurements.
We present a model for the decay D+ --> K- pi+ pi+. The weak interaction part of this reaction is described using the effective weak Hamiltonian in the factorisation approach. Hadronic final state interactions are taken into account through the Kpi scalar and vector form factors fulfilling analyticity, unitarity and chiral symmetry constraints. The model has only two free parameters that are fixed from experimental branching ratios. We show that the modulus and phase of the S wave thus obtained agree nicely with experiment up to 1.55 GeV. We perform Monte Carlo simulations to compare the predicted Dalitz plot with experimental analyses. Allowing for a global phase difference between the S and P waves of -65 degrees, the Dalitz plot of the D+ --> K- pi+ pi+ decay, the Kpi invariant mass spectra and the total branching ratio due to S-wave interactions are well reproduced.
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.
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