The cross sections of the processes $e^+ e^- \to K^+ K^- J/\psi$ and $K_S^0K_S^0J/\psi$ are measured via initial state radiation at center-of-mass energies between the threshold and 6.0~GeV using a data sample of 980~fb$^{-1}$ collected with the Belle detector on or near the $\Upsilon(nS)$ resonances, where $n=$1, 2, ..., 5. The cross sections for $e^+ e^- \to K^+ K^- J/\psi$ are at a few pb level and the average cross section for $e^+ e^- \to K_S^0K_S^0J/\psi$ is $1.8\pm 0.6 (\rm stat.)\pm 0.3 (\rm syst.)$~pb between 4.4 and 5.2~GeV. All of them are consistent with previously published results with improved precision. A search for resonant structures and associated intermediate states in the cross section of the process $e^+ e^- \to K^+ K^- J/\psi$ is performed.
Cross section for K+ K- J/PSI production as a function of SQRT(S). Upper limits include the systematic errors.
Cross section for K0S K0S J/PSI production as a function of SQRT(S).
Average cross section for K0S K0S J/PSI production.
Results on charged pion and kaon production in central Pb+Pb collisions at 20A and 30A GeV are presented and compared to data at lower and higher energies. A rapid change of the energy dependence is observed around 30A GeV for the yields of pions and kaons as well as for the shape of the transverse mass spectra. The change is compatible with the prediction that the threshold for production of a state of deconfined matter at the early stage of the collisions is located at low SPS energies.
Transverse mass spectra for pion production in the central rapidity region for collisions at 20 GeV per nucleon.
Transverse mass spectra for pion production in the central rapidity region for collisions at 30 GeV per nucleon.
Transverse mass spectra for kaon production in the central rapidity region for collisions at 20 GeV per nucleon.
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We present results on inclusive particle production in the antineutrino charged current induced hadron jets observed in the Fermilab 15 ft bubble chamber. Fractional energy distributions, particle ratios and average multiplicities of the hadrons in the jets are measured. Ratios between the inclusive production rates of different mesons in the jets are studied to seek evidence for the d-quark origin of the observed hadrons. Good over-all agreement with the hypothesis of d-quark fragmentation with universal fragmentation functions obeying isospin systematics is established.
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The results of a study of strange particle production in charged current $\bar{\nu}_{\mu} N$ interactions in the Fermilab 15 ft bubble chamber filled with a heavy $Ne-H_2$ mixture are presented. Production rates and average multiplicities of $K^0$'s and Λ's as functions of W 2 and Q 2 are given. The experimental data agree well with the quark-parton model predictions if a yield of 0.06 ± 0.02 of $K^0$'s and Λ's from charm production is included. Upper limits for D-meson production are given and the shape of the charmed quark fragmentation function is discussed. Inclusive production of the K ∗ (890) and Σ(1385) resonances is measured and it is shown that only about 5% of the K 0 mesons and Λ hyperons results from resonance decays. Relative production rates of neutral strange particles on proton and neutron targets are studied.
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THE AVERAGE PHASE IS -130.9 +- 2.7 DEG (NO EXPLICIT MOMENTUM DEPENDENCE). USING ABS(ETA+-) = 2.3*10**-3.
REGENERATION AMPLITUDE ASSUMING MOMENTUM INDEPENDENT CONSTANT PHASE.
CROSS SECTION DIFFERENCES ASSUMING MOMENTUM INDEPENDENT CONSTANT PHASE.
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