Inclusive production cross sections of $\pi^\pm$, $K^\pm$ and $p\bar{p}$ per hadronic $e^+e^-$ annihilation event in $e^+e^-$ are measured at a center-of-mass energy of 10.54 GeV, using a relatively small sample of very high quality data from the BaBar experiment at the PEP-II $B$-factory at the SLAC National Accelerator Laboratory. The drift chamber and Cherenkov detector provide clean samples of identified $\pi^\pm$, $K^\pm$ and $p\bar{p}$ over a wide range of momenta. Since the center-of-mass energy is below the threshold to produce a $B\bar{B}$ pair, with $B$ a bottom-quark meson, these data represent a pure $e^+e^- \rightarrow q\bar{q}$ sample with four quark flavors, and are used to test QCD predictions and hadronization models. Combined with measurements at other energies, in particular at the $Z^0$ resonance, they also provide precise constraints on the scaling properties of the hadronization process over a wide energy range.
Differential cross section for prompt PI+-, K+- and PBAR/P production.
Differential cross section for conventional PI+-, K+- and PBAR/P production.
Integrated cross sections for prompt PI+-, K+- and PBAR/P production. The second (sys) error is the uncertainty due to the model dependence of the extrapolation.
We report the first observation of $K^{\star}(892)^{0}\to\pi K$ in relativistic heavy ion collisions. The transverse momentum spectrum of $(K^{\star0}+\bar{K}^{\star0})/2$ from central Au+Au collisions at $\sqrt{s_{_{NN}}}=130$ GeV is presented. The ratios of the $K^{\star0}$ yield derived from these data to the yields of negative hadrons, charged kaons, and $\phi$ mesons have been measured in central and minimum bias collisions and compared with model predictions and comparable $e^{+}e^{-}$, $pp$, and $\bar{p}p$ results. The data indicate no dramatic reduction of $K^{\star0}$ production in relativistic heavy ion collisions despite expected losses due to rescattering effects.
Transverse mass spectrum of K*0 with YRAP = -0.5 to 0.5 for the 14 PCT most central interactions. Numerical values requested from the authors.
K*0 to negative hadron ratio using hadron data from Adler et al PRL 87,112303(2001).
K*0 to kaon ratio using STAR kaon data.
The production of $J/\psi$ mesons in continuum $e^+e^-$ annihilations has been studied with the BABAR detector at energies near the $\Upsilon(4S)$ resonance, approximately 10.6 GeV. The mesons are distinguished from $J/\psi$ production in B decays through their center-of-mass momentum and energy. We measure the cross section $e^+e^-\to J/\psi X$ to be $2.52\pm 0.21\pm 0.21$ pb: for momentum above 2 GeV/c, it is $1.87\pm 0.10\pm 0.15$ pb. We set a 90% confidence level upper limit on the branching fraction for direct $\Upsilon(4S)$\to J/\psi X$ decays at $4.7\times 10^{-4}$.
Cross section measurement.
We present measurements of time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurement uses a data sample of 23 million Upsilon(4S)-->B-anti-B decays collected by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we find events where one neutral B meson is fully reconstructed in a CP eigenstate containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the Standard Model is proportional to sin2beta, is derived from the decay time distributions in such events. The result is sin2beta=0.34 +/- 0.20 (stat) +/- 0.05 (syst).
Standard Model predicts the time-dependent rate asymmetry as follows: A(t) = (B0(t)-BBAR0(t))/(B0(t)+BBAR0(t)) = SIN(2*BETA)*SIN(Delta(M)*t), where Delta(M) is the mass difference between the two B0 mass eigenstates. The total systematic error equals +0.50 -0.46.
The isoscalar structure functions xF_3 and F_2 are measured as functions of x averaged over all Q~2 permissible for the range 6 to 28 GeV of incident (anti)neutrino energy. With the measured values of xF_3, the value of the Gross-Llewellyn Smith sum rule is found to be $\int_{0}~{1}{F_3 dx} = 2.13\pm0.38 (stat)\pm 0.26 (syst)$. The QCD analysis of xF_3 provides $\Lambda_{\overline{MS}} =358 \pm 59 MeV$ . The obtained value of the strong interaction constant $\alpha_S (M_Z)=0.120~{+3}_{-4}$ is larger than most of the deep inelastic scattering results.
The value of F2 is extracted with R = 0. The difference F2(C=R=.1)-F2(C=R=0.) is also presented.
The results of total cross section measurements for theνμ,\(\bar \nu _\mu\) interactions with isoscalar target in the 3 – 30 GeV energy range have been presented. The data were obtained with the IHEP-JINR Neutrino Detector in the “natural” neutrino beams of the U-70 accelerator. Neutrino fluxes were obtained by averaging the spectra, based on the calculations with the use of the experimental data on secondary particle yields from the target and muon fluxes measurements in 9 gaps of the muon filter, as well as the spectra determined from quasi-elastic events and spectra defined by extrapolating differential distributiondσ/dy in the regiony=0. The significant deviation from the linear dependence forσtot versus neutrino energy is determined in the energy range less than 15 GeV.
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Using the MD-1 detector at the VEPP-4e+e− strorage ring we have measured the inclusive Λ and370-1 production rates in direct Γ(1S) decays
Lambda x spectrum in direct upsilon(1S) decay.
Lambda multiplicity in direct upsilon(1S) decays.
Lambda multiplicity in surrounding continuum.
The total cross section for γγ→hadrons was measured as a function of the invariant massW of the system (1.25 to 4.25 GeV) at thee+e−-collider VEPP-4 with the detector MD-1. For the first time the data were obtained by detecting both scattered leptons with almost zero emission angles. The mean squared four momentum transfer 〈q2〉 is −0.005 GeV2, the rmsW resolution is 100–250 MeV. The data on the mean charged multiplicity 〈nC〉 are well described by the function 〈nC〉=(1.62 ±0.37)+(1.83±0.45)·ln(W(GeV)). TheW dependence of the total cross section is consistent with the theoretical prediction σ(nb)=240+270/W(GeV).
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The cross section per nucleon is evaluated with assumption of the linear atomic number dependence. SIG(C=NEUTRINO) and SIG(C=ANTINEUTRINO) are corresponded to the NUMU and NUMUBAR data, respectevly. CLOOP-OVER.
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