Date

Study of Heavy Flavor Production in Events With a Muon Accompanied by Jet(s) at the {CERN} Proton - Anti-proton Collider

The UA1 collaboration Albajar, C. ; Albrow, M.G. ; Allkofer, O.C. ; et al.
Z.Phys.C 37 (1988) 489-503, 1988.
Inspire Record 250762 DOI 10.17182/hepdata.15677

We present a study of heavy flavour (charm and beauty) production using data collected with the UA1 detector at the CERN Proton-Antiproton collider at a centre-of-mass energy of 630 GeV for an integrated luminosity of 556 nb−1. This follows our earlier study ofb\(\bar b\) andc\(\bar c\) production in dimuon events and the evidence for mixing betweenB0 and\(\bar B^0 \) states. Properties of an inclusive sample of events containing a muon withpT>6 GeV/c are compared with QCD predictions for heavy flavour production, using the ISAJET Monte Carlo program. The predicted largepT muon yield from heavy flavour production and decay agrees with the data to within 30%. For events with a muon ofpT>10 GeV/c and at least one jet withET>10 GeV, we measure the ratio charm/(charm+beauty) to be (24±8±9)%. We also show that the correlations observed between the two heavy quark jets expected by flavour conservation are consistent with the mixture of lowest and higher order QCD processes. We study in detail the topological and kinematic properties of a subsample of events containing a highpT muon and one or more jets. The good agreement of the theoretical predictions with our data in a region dominated by the production of charm and beauty shows that one of the main background sources to a new heavy quark signature is well understood.

3 data tables

No description provided.

Numerical values supplied by K.Wacker. Muon spectrum with at least one jet with PT > 12 GeV/c.

No description provided.


Search for Top Quark in e+ e- Collisions at s**(1/2) = 52-GeV

The TOPAZ collaboration Adachi, I. ; Aihara, H. ; Dijkstra, H.B. ; et al.
Phys.Rev.Lett. 60 (1988) 97, 1988.
Inspire Record 251830 DOI 10.17182/hepdata.20141

We searched for possible signatures of top-quark production in 508 e+e− hadronic annihilation events collected at s=52 GeV by the TOPAZ detector at the KEK e+e− collider TRISTAN. The observed hadronic cross section and shape of hadronic events are consistent with the standard-model predictions without top quarks. A lower limit (95% confidence level) on the mass of the lightest top meson is set at 25.8 GeV.

1 data table

No description provided.


Hyperon Production in $e^+ e^-$ Annihilation at 10-{GeV} Center-of-mass Energy

The ARGUS collaboration Albrecht, H. ; Binder, U. ; Bockmann, P. ; et al.
Z.Phys.C 39 (1988) 177, 1988.
Inspire Record 251097 DOI 10.17182/hepdata.1697

The production cross sections for the Λ, Σ0, Ξ−, Σ0 (1385), Ξ0 (1530) and Ω− hyperons have been measured, both in the continuum and in direct ϒ decays. Baryon rates in direct ϒ decays are enhanced by a factor of 2.5 or more compared to the continuum. Such a large baryon enhancement cannot be explained by standard fragmentation models. The strangeness suppression for baryons and mesons turns out to be the same. A strong suppression of spin 3/2 states is observed.

23 data tables

Hyperon rates per multihadronic event in direct UPSILON decays.

Hyperon rates per multihadronic event in the continuum.

LAMBDA spectrum (1/SIG(had))*D(SIG)/D(X) for UPSILON (1S) direct decays, with X = P/Pmax.

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Charged $K^*$ Production in $e^+ e^-$ Annihilations at 29-{GeV}

Abachi, S. ; Baringer, Philip S. ; Bylsma, B.G. ; et al.
Phys.Lett.B 199 (1987) 151-154, 1987.
Inspire Record 22433 DOI 10.17182/hepdata.6521

We report a measurement of the charged K ∗ (892) production in e + e − annihilations at 29 GeV center-of-mass energy. The 300 pb −1 data sample used for this analysis is obtained with the High Resolution Spectrometer at the SLAC storage ring PEP. The total mean multiplicity is measured to be 〈n K ∗± (892) 〉=0.62±0.045±0.04 per hadronic event. Evidence is also given for the production of a charged K 2 ∗ (1430) tensor meson.

6 data tables

Extrapolation to full x-range using Lund model.

Data requested from authors.

Extrapolation to full x-range usisng fragmentation friction predicted by the Webber cluster model.

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Measurement of R and Search for New Heavy Quarks in $e^+ e^-$ Annihilation at 50-{GeV} and 52-{GeV} Center-of-mass Energies

The Venus collaboration Yoshida, H. ; Chiba, Y. ; Endo, I. ; et al.
Phys.Lett.B 198 (1987) 570, 1987.
Inspire Record 251274 DOI 10.17182/hepdata.30074

The total cross section for the process of the e + e - annihilation into hadrons has been measured at the centre-of-mass energies of 50 GeV and 52 GeV and a search has been made for new heavy quarks. The ratios R = σ ( e + e - → hadrons )/ σ point ( e + e - → μ + μ - ) obtained are 4.4±0.5 at 50 GeV and 4.7±0.3 at 52 GeV, respectively. An additional systematic uncertainty is 10%. From the event shape analysis we found no evidence for a new quark with charge 2 3 e .

1 data table

No description provided.


Observation of the Selective Coupling of $K^*$ States to the $K^- \eta$ Channel

Aston, D. ; Awaji, N. ; Bienz, T. ; et al.
Phys.Lett.B 201 (1988) 169-175, 1988.
Inspire Record 250272 DOI 10.17182/hepdata.30009

The K − η effective mass spectrum in the reaction K − p→K − π + π − π 0 p at 11 GeV/ c has a prominent peak at ≈1.75 GeV/ c 2 , which is shown to be due to the K 3 ∗ (1780) by a spherical harmonic moments analysis and amplitude decomposition; there is no significant signal for K 2 ∗ (1430). The measured branching fractions for the leading L =1 and L =2 K ∗, s, [BF(K 2 ∗ (1430)→Kη) <0.45% at the 95% CL and BF ( K 3 ∗ (1780)→ Kη )=9.4±3.4%] confirm the SU(3) prediction that the Kη channel couples preferentially to odd spin K *, s.

2 data tables

Numerical data of acceptance corrected spherical harmonic moments requested from authors.

Including systematic error.


High Transverse Momentum $J/\psi$ Production at the {CERN} Proton - Anti-proton Collider

The UA1 collaboration Albajar, C. ; Albrow, M.G. ; Allkofer, O.C. ; et al.
Phys.Lett.B 200 (1988) 380-390, 1988.
Inspire Record 250764 DOI 10.17182/hepdata.28173

We have studied high transverse momentum J/ψ production in p p interactions at s =630 GeV . The measured cross section times branching fraction for J/ψ→μ + μ − production with p T ⩾5 GeV / c and | y |<2.0 is 7.5±0.7±1.2 nb . The event topology is used to establish that there is J/ψ production from both the direct production of c c bound states and the decay of B hadrons. The inferred yield of J/ψ from beauty decays is compatible with our estimates of beauty production in other channels.

3 data tables

Data extracted from figure with g3data.

Data extracted from figure with g3data.


Measurements of r and a Search for Heavy Quark Production in e+ e- Annihilation at s**(1/2) = 50-GeV and 52-GeV

The AMY collaboration Sagawa, H. ; Mori, T. ; Abe, K. ; et al.
Phys.Rev.Lett. 60 (1988) 93, 1988.
Inspire Record 251270 DOI 10.17182/hepdata.20143

The ratio R of the cross section for e+e− annihilation into hadronic final states to the QED cross section for muon-pair production is measured to be 4.34±0.45±0.30 and 4.23±0.20±0.21 at c.m. energies of 50 and 52 GeV, respectively. From these values of R and an analysis of the event shapes we deduce a 95%-confidence-level upper limit for the production rate of new heavy charge +23e or −13e quarks to be 0.19 units of R.

1 data table

No description provided.


Search for a Narrow Resonance in Anti-proton - Proton Annihilation Cross-sections in the Beam Momentum Range Between 400-{MeV}/$c$ and 600-{MeV}/$c$

Brückner, W. ; Cujec, B. ; Döbbeling, H. ; et al.
Phys.Lett.B 197 (1987) 463, 1987.
Inspire Record 249661 DOI 10.17182/hepdata.30103

A measurement of the p p annihilation cross section in the beam momentum region between 400 and 600 MeV/ c has been performed with a mass resolution of 1 MeV/ c 2 and statistical precision generally better than 1%. No evidence for the X(1935) resonance is found. The upper limit at the 90% confidence level is 5 mb MeV/ c 2 for a width of 2 MeV/ c 2 .

1 data table

Statistical errors only.


Intermediate Vector Boson Cross-Sections at the CERN Super Proton Synchrotron Collider and the Number of Neutrino Types

The UA1 collaboration Albajar, C. ; Albrow, M.G. ; Allkofer, O.C. ; et al.
Phys.Lett.B 198 (1987) 271-280, 1987.
Inspire Record 249745 DOI 10.17182/hepdata.30076

We present updated results from the UA1 experiment on cross sections times leptonic branching ratios for intermediate vector bosons produced in proton-antiproton collisions at a centre-of-mass energy of 0.630 TeV. We find that σ·B( W → l βn)=0.63±0.04±0.10 nb and σ·B( Z 0 → l + l − =0.071±0.011 nb where l denotes an average of electron and muon channels. An average over all data (electron and muon channels at 0.546 and 0.630 TeV) gives a ratio of R≡σ·( W → l ν)/σ·B( Z 0 → l + l − ) = 9.1 +1.7 −1.2 . Using current theoretical predictions for this quantity, limits are extracted on the number of light neutrino types. Combining UA1 and UA2 data and imposing the bound N ν ⩾3 we find that N ν ⩽5.9 at 90% CL. Constraints on the mass of the top quark are also discussed.

9 data tables

THE CORRESPONDING VALUE FROM UA2 IS BR*SIG = 0.61+-0.10+-0.07.

No description provided.

THE CORRESPONDING VALUE FROM UA2 IS BR*SIG = 0.57+-0.04+-0.07.

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