Masayoshi Wake

Measurement of R and search for new heavy quarks in e+e- annihilation at 50 and 52 GeV centre-of-mass energies

Abstract 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)/σpoint(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 .

Search for the Top Quark in e+e- Annihilation at \(\sqrt{s}=50\) GeV: The First Result from the VENUS Detector at TRISTAN

A result of the search for the top quark in e + e - annihilation into hadrons at \(\sqrt{s}=50\) GeV is presented. The experiment has been perforrnxed using the VENUS detector at TRISTAN. No evidence has been found for the production of the top quark. From the study using the event shape of the multihadron events, the upper limit of the production cross section is found to be 16 pb at thcc 95% confidence level.

Electrical Properties of Electron Bubble in Liquid Helium II

Electrical properties of electron bubble produced by a hot tungsten filament immersed in the liquid helium bath were investigated. The electrical current between the filament and the surrounding plate could well be explained by an ohmic flow of the bubble under a strong space charge field. The mobility of the electron bubble was strongly field dependent and the roton creation process was newly introduced for the bubble motion in addition to the well known processes of the phonon and roton scatterings and the interaction between vortex and ion.

Study of multihadron events with isolated leptons in e+e− annihilation at 50⩽sles;55 GeV

Abstract We have studied inclusive lepton production in e + e − annihilations into multihadrons in the energy range between √ s =50 and 55 GeV using the VENUS detector at TRISTAN, KEK. Though MARK-J and JADE groups at PETRA found an excess of isolated muon events at √ s ⩾46.3 GeV, we have not observed such an anomaly in muon nor in electron production. The observed rates of isolated leptons are consistent with the production and decay of five known quarks.

Measurement of the Reactions

The differential cross sections for e + e - → e + e - and e + e - →γγ have been measured at the highest energy of \(\sqrt{s}=52\) GeV in e + e - collisions.The process e + e - → e + e - is well understood within the framework of the standard model of electroweak interactions. The reaction e + e - →γγ is found to be in good agreement with QED. The 95% confidence limits obtained for the QED cut-off parameters are \(\varLambda_{+}>61\) GeV and \(\varLambda_{-}>72\) GeV for e + e - →γγ.The differential cross sections for e + e - → e + e - and e + e - →γγ have been measured at the highest energy of \(\sqrt{s}=52\) GeV in e + e - collisions.The process e + e - → e + e - is well understood within the framework of the standard model of electroweak interactions. The reaction e + e - →γγ is found to be in good agreement with QED. The 95% confidence limits obtained for the QED cut-off parameters are \(\varLambda_{+}>61\) GeV and \(\varLambda_{-}>72\) GeV for e + e - →γγ.

e^+ e^- \to e^+ e^-

The differential cross sections for e + e - → e + e - and e + e - →γγ have been measured at the highest energy of \(\sqrt{s}=52\) GeV in e + e - collisions.The process e + e - → e + e - is well understood within the framework of the standard model of electroweak interactions. The reaction e + e - →γγ is found to be in good agreement with QED. The 95% confidence limits obtained for the QED cut-off parameters are \(\varLambda_{+}>61\) GeV and \(\varLambda_{-}>72\) GeV for e + e - →γγ.The differential cross sections for e + e - → e + e - and e + e - →γγ have been measured at the highest energy of \(\sqrt{s}=52\) GeV in e + e - collisions.The process e + e - → e + e - is well understood within the framework of the standard model of electroweak interactions. The reaction e + e - →γγ is found to be in good agreement with QED. The 95% confidence limits obtained for the QED cut-off parameters are \(\varLambda_{+}>61\) GeV and \(\varLambda_{-}>72\) GeV for e + e - →γγ.

and

The differential cross sections for e + e - → e + e - and e + e - →γγ have been measured at the highest energy of \(\sqrt{s}=52\) GeV in e + e - collisions.The process e + e - → e + e - is well understood within the framework of the standard model of electroweak interactions. The reaction e + e - →γγ is found to be in good agreement with QED. The 95% confidence limits obtained for the QED cut-off parameters are \(\varLambda_{+}>61\) GeV and \(\varLambda_{-}>72\) GeV for e + e - →γγ.The differential cross sections for e + e - → e + e - and e + e - →γγ have been measured at the highest energy of \(\sqrt{s}=52\) GeV in e + e - collisions.The process e + e - → e + e - is well understood within the framework of the standard model of electroweak interactions. The reaction e + e - →γγ is found to be in good agreement with QED. The 95% confidence limits obtained for the QED cut-off parameters are \(\varLambda_{+}>61\) GeV and \(\varLambda_{-}>72\) GeV for e + e - →γγ.