12 research outputs found
A Measurement of Psi(2S) Resonance Parameters
Cross sections for e+e- to hadons, pi+pi- J/Psi, and mu+mu- have been
measured in the vicinity of the Psi(2S) resonance using the BESII detector
operated at the BEPC. The Psi(2S) total width; partial widths to hadrons,
pi+pi- J/Psi, muons; and corresponding branching fractions have been determined
to be Gamma(total)= (264+-27) keV; Gamma(hadron)= (258+-26) keV, Gamma(mu)=
(2.44+-0.21) keV, and Gamma(pi+pi- J/Psi)= (85+-8.7) keV; and Br(hadron)=
(97.79+-0.15)%, Br(pi+pi- J/Psi)= (32+-1.4)%, Br(mu)= (0.93+-0.08)%,
respectively.Comment: 8 pages, 6 figure
Measurements of Cabibbo Suppressed Hadronic Decay Fractions of Charmed D0 and D+ Mesons
Using data collected with the BESII detector at storage ring
Beijing Electron Positron Collider, the measurements of relative branching
fractions for seven Cabibbo suppressed hadronic weak decays ,
, and , , and are presented.Comment: 11 pages, 5 figure
Effect of oligofructose-enriched inulin on bone metabolism in girls with low calcium intakes
Angiotensin converting enzyme inhibition in chronic stable angina: effects on myocardial ischaemia and comparison with nifedipine.
Top quark physics at hadron colliders
The top quark, discovered at the FERMILAB TEVATRON collider in 1995, is the heaviest known elementary particle. Today, ten years later, still relatively little is known about its properties. The strong and weak interactions of the top quark are not nearly as well studied as those of the other quarks and leptons. The strong interaction is most directly measured in top quark pair production. The weak interaction is measured in top quark decay and single top quark production, which remains thus far unobserved. The large top-quark mass of about 175 GeV/c2 suggests that it may play a special role in nature. It behaves differently from all other quarks due to its large mass and its correspondingly short lifetime. The top quark decays before it hadronises, passing its spin information on to its decay products. Therefore, it is possible to measure observables that depend on the top quark spin, providing a unique environment for tests of the Standard Model and for searches for physics beyond the Standard Model. This report summarises the latest measurements and studies of top quark properties and rare decays from the TEVATRON in Run II. With more than 1 fb-1 of luminosity delivered to each experiment, CDF and DO, top quark physics at the TEVATRON is at a turning point from first studies to precision measurements with sensitivity to new physics. An outlook onto top quark physics at the Large Hadron Collider (LHC) at CERN, planned to begin operation in the year 2007, is also given
J / psi production via initial state radiation in e+ e- ---> mu+ mu- gamma at an e+ e- center-of-mass energy near 10.6-GeV
We have used a study of the process e+e- --> mu+ mu- gamma at a
center-of-mass energy near the Y(4S) resonance for a mu+ mu- invariant mass
range near the J/psi mass to extract the cross section sigma(e+e- --> J/psi
gamma --> mu+ mu- gamma). The data set, corresponding to an integrated
luminosity of 88.4 fb-1, was collected using the BaBar detector at the PEP-II
collider. We measure the product Gamma(J/psi --> e+e-)B(J/psi --> mu+ mu-) to
be 0.330 +/- 0.008(stat) +/- 0.007(syst) keV. Using the world averages for
B(J/psi --> mu+ mu-) and B(J/psi --> e+e-), we derive the J/psi electronic and
total widths: Gamma(J/psi --> e+e-)=5.61+/-0.20 keV and Gamma=94.7+/-4.4 keV.Comment: 8 pages, 4 postscript figues, submitted to Phys. Rev. D(Rapid
Communications