We have measured the magnetic moments of the Σ+ and Σ¯ − hyperons produced by 800-GeV protons incident on a Cu target. We determine the Σ+ magnetic moment to be (2.4613±0.0034±0.0040)μN where the uncertainties are statistical and systematic, respectively. In this first measurement we determine the magnetic moment of the Σ¯ − to be -(2.428±0.036±0.007)μN. The magnetic moments of the Σ+ and Σ¯ − are consistent with each other in magnitude but opposite in sign as required by CPT invariance.
No description provided.
No description provided.
We have mesured the polarization of 375-GeV/c Σ+ and Σ¯ − hyperons produced by 800-GeV/c protons incident on a Cu target. We find that the Σ+ polarization rises with increasing pt to a maximum of 16% at pt=1.0 GeV/c and then decreases to 10% at pt=1.8 GeV/c. We compare this Σ+ polarization with data at lower energies. The Σ¯ − polarization has been measured for the first time. It has the same sign as the Σ+ but smaller magnitude in a similar kinematical region.
Data from Horizontal targeting.
Data from Vertical targeting.
Data from Horizontal targeting.
We have measured the branching ratio for the hyperon radiative decay Ξ−→Σ−γ from a sample of 211±33 events obtained in the polarized 375 GeV/c charged hyperon beam at Fermilab. We find B(Ξ−→Σ−γ/Ξ−→Λ0π−)=(1.22±0.23±0.06)×10−4 where the quoted errors are statistical and systematic, respectively. We have also obtained an indication that the sign of the asymmetry parameter of this decay is positive.
Polarized 375 GeV charged hyperon beam at Fermilab. Sample of 211 +- 33 events.
From a muon-proton scattering experiment with a streamer chamber at the Stanford Linear Accelerator we present results in the ranges 0.3
THE ABSOLUTE TOTAL CROSS SECTION IS FROM A FIT TO THE MIT-SLAC ELECTRON SCATTERING DATA BY W. ATWOOD AND S. STEIN.
No description provided.
FOR 0.6 < M(PI+ PI-) < 0.9 GEV, USING THE METHOD OF MOMENTS.
In a streamer-chamber experiment at the Stanford Linear Accelerator Center, we observed hadron production in inelastic collisions of 14-GeV positive muons in a liquid hydrogen target. We report on the experiment, the analysis, and the resulting cross sections for hadronic prongs as well as the charged-hadron multiplicity distributions.
No description provided.
No description provided.
A clear, prompt dimuon signal has been observed in a low-statistics streamer-chamber experiment with 16-GeV/c πp interactions. The good mass resolution makes it possible to identify the contributions from ρ and ω decays and η and ω Dalitz decays. An excess of events is observed in the mass region ∼400-600 MeV which is not accounted for by the above-mentioned decays.
The data with PI+- beam obtained from the combination of PI+ and PI- beams.
We utilize the angle and momentum resolution of our apparatus to study the polarization of 375 GeV/c Σ+ hyperons produced by 800 GeV/c protons incident on a Cu target. By examining in detail two of our high statistics data samples, we find evidence for structure in the pt dependence of Σ+ polarization and are able to extract the xF dependence of the Σ+ polarization and compare it with xF behavior in the Λ0 and Ξ− systems.
0.9 mrad horizontal sample.
2.9 mrad horizontal sample.
3.3 mrad horizontal sample.
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.
The process e+e- --> p anti-p gamma is studied using 469 fb-1 of integrated luminosity collected with the BABAR detector at the PEP-II collider, at an e+e- center-of-mass energy of 10.6 GeV. From the analysis of the p anti-p invariant mass spectrum, the energy dependence of the cross section for e+e- --> p anti-p is measured from threshold to 4.5 GeV. The energy dependence of the ratio of electric and magnetic form factors, |G_E/G_M|, and the asymmetry in the proton angular distribution are measured for p anti-p masses below 3 GeV. We also measure the branching fractions for the decays J/psi --> p anti-p and psi(2S) --> p anti p.
Measurement of the cross section as a function of the invariant mass of the PBAR-P system and the effective form factor for the reaction E+ E- --> PBAR P. The contributions from J/PSI and PSI(25) decaying to PBAR-P have been subtracted. The form factor error is the combined statistical and systematic.
We present measurements of the inclusive production of antideuterons in $e^+e^-$ annihilation into hadrons at $\approx 10.58 \mathrm{\,Ge\kern -0.1em V}$ center-of-mass energy and in $\Upsilon(1S,2S,3S)$ decays. The results are obtained using data collected by the BABAR detector at the PEP-II electron-positron collider. Assuming a fireball spectral shape for the emitted antideuteron momentum, we find $\mathcal{B}(\Upsilon(1S) \to \bar{d}X) = (2.81 \pm 0.49 \mathrm{(stat)} {}^{+0.20}_{-0.24} \mathrm{(syst)})/! \times /! 10^{-5}$, $\mathcal{B}(\Upsilon(2S) \to \bar{d}X) = (2.64 \pm 0.11 \mathrm{(stat)} {}^{+0.26}_{-0.21} \mathrm{(syst)})/! \times /! 10^{-5}$, $\mathcal{B}(\Upsilon(3S) \to \bar{d}X) = (2.33 \pm 0.15 \mathrm{(stat)} {}^{+0.31}_{-0.28} \mathrm{(syst)})/! \times /! 10^{-5}$, and $\sigma (e^+e^- \to \bar{d}X) = (9.63 \pm 0.41 \mathrm{(stat)} {}^{+1.17}_{-1.01} \mathrm{(syst)}) \mbox{\,fb}$.
The rate of antideuteron production from the decay of UPSILON(3S).
The rate of antideuteron production from the decay of UPSILON(2S).
The rate of antideuteron production from the decay of UPSILON(1S).
Forum