Inclusive <math altimg="si2.gif" display="inline" overflow="scroll"><msup><mi>K</mi><mo>+</mo></msup></math> production in proton–proton collisions has been measured at a beam energy of 2.16 GeV using the COSY-ANKE magnetic spectrometer. The resulting spectrum, as well as those corresponding to <math altimg="si3.gif" display="inline" overflow="scroll"><msup><mi>K</mi><mo>+</mo></msup><mi>p</mi></math> and <math altimg="si4.gif" display="inline" overflow="scroll"><msup><mi>K</mi><mo>+</mo></msup><msup><mi>π</mi><mo>+</mo></msup></math> correlated pairs, can all be well described using consistent values of the total cross sections for the <math altimg="si5.gif" display="inline" overflow="scroll"><mi>p</mi><mi>p</mi><mo>→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>p</mi><mi>Λ</mi></math>, <math altimg="si6.gif" display="inline" overflow="scroll"><mi>p</mi><mi>p</mi><mo>→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>p</mi><msup><mi>Σ</mi><mn>0</mn></msup></math>, and <math altimg="si7.gif" display="inline" overflow="scroll"><mi>p</mi><mi>p</mi><mo>→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>n</mi><msup><mi>Σ</mi><mo>+</mo></msup></math> reactions. While the resulting values for Λ and <math altimg="si8.gif" display="inline" overflow="scroll"><msup><mi>Σ</mi><mn>0</mn></msup></math> production are in good agreement with world data, our value for the total <math altimg="si9.gif" display="inline" overflow="scroll"><msup><mi>Σ</mi><mo>+</mo></msup></math> production cross section, <math altimg="si10.gif" display="inline" overflow="scroll"><mi>σ</mi><mo stretchy="false">(</mo><mi>p</mi><mi>p</mi><mo>→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>n</mi><msup><mi>Σ</mi><mo>+</mo></msup><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>2.5</mn><mo>±</mo><msub><mn>0.6</mn><mi mathvariant="normal">stat</mi></msub><mo>±</mo><msub><mn>0.4</mn><mi mathvariant="normal">syst</mi></msub><mo stretchy="false">)</mo><mtext> μb</mtext></math> at an excess energy of <math altimg="si11.gif" display="inline" overflow="scroll"><mi>ε</mi><mo>=</mo><mn>129</mn><mtext> MeV</mtext></math>, could only be reconciled with other recently published data if there were a highly unusual near threshold behaviour.
Total cross section for the reaction P P --> K+ N SIGMA+.
Total cross section for the reaction P P --> K+ P LAMBDA.
Total cross section for the reaction P P --> K+ P SIGMA0.
This Letter describes a measurement of the muon cross section originating from b quark decay in the forward rapidity range 2.4 < y(mu) < 3.2 in pbarp collisions at sqrt(s) = 1.8 TeV. The data used in this analysis were collected by the D0 experiment at the Fermilab Tevatron. We find that NLO QCD calculations underestimate b quark production by a factor of four in the forward rapidity region. A cross section measurement using muon+jet data has been included in this version of the paper.
The forward muon cross section (per unit rapidity).
The cross section for muons originating from b-quark decay.
Integrated cross sections for muons originating from b-quark decay. The statistical and systematic errors are added in quadrature.
We have measured the reaction γ p → p π + π − in the DESY 1 m Streamer Chamber. The dominant ϱ o production is analyzed in terms of various models.
No description provided.
FOR ALL EVENTS.
FOR ALL TWO PION EVENTS.
Forum