The differential cross section of dσ(e + e − → e + e − D * ± X)/dPT was measured using a soft-pion analysis of D * ± → π ± s D 0 (D 0 ) at TRISTAN. The average √ s was 58.1 GeV and the integrated luminosity used in this analysis was 198 pb −1 , respectively. * published in Phys. Lett. B 328 (1994) 535. †

We studied the energy-energy correlation ( EEC ) and its asymmetry (AEEC) using e ÷ e-hadronic annihilation events obtained at V~= 53.3 GeV and 59.5 GeV with the TOPAZ detector at the TRISTAN collider. We used a Monte Carlo simulation combined with the QCD matrix elements by Gottschalk and Shatz and the Lund string fragmentation model. By comparing the experimental data with simulated events, we determined the strong coupling constant as at both energies. The results are 0.129_+ 0.007 (star) _+ 0.010(syst) at \/s= 53.3 GeV and 0.122_+ 0.008 (stat) _+ 0.010(syst) at 59.5 GeV.

We have measured, with electron tagging, the forward-backward asymmetries of charm-and bottom-quark pair productions at √ s =58.01GeV, based on 23,783 hadronic events selected from a data sample of 197pb −1 taken with the TOPAZ detector at TRISTAN. The measured forward-backward asymmetries are A c F B = −0.49±0.20(stat.)±0.08(sys.) and A b F B = −0.64±0.35(stat.)±0.13(sys.), which are consistent with the standard model predictions.

We carded out the energy scan between ECM = 58 and 60 GeV at the TRISTAN e+e -collider to search for the possible narrow resonance suggested by the L3 experiment at LEP. The total cross sections are measured for ~,7, multihadron, e+e -and /~+/z-productions at ten energy points coveting this energy range almost uniformly. The results are in good agreement with the Standard Model predictions, and 95% confidence level upper limits are set to Fee x BR of the hypothetical scalar and tensor resonances.

Department o/Ph~ sws. .\agoya t mversttv, .\agora 464. Japan t, KI.K. ,~attonal Laboratory/or lhgh /-.nergv Physics. Tukuha 305. Japan Department of..lpphed Phi sits. ~)hlo ~ nt~ersttv of lgttculture and l echnoh)gv, 7 Okl o 184. Japan ' Department o! Physic s. ~ nt~ersttv o/To~ ~ o, lol, i o 113. Japan ¢ Department o/t'hl,~t¢~. \ara It omen's t nt~etsttv. %ara 630. Japan t Department o/Physic s. Purdue ( m~t'r~ttl. 11 'est Lala~ cite. 1~' 47907 ( 'S" 1 g Institute h)t \uclear Study. l_'tll~t'tsttl o/7ohio, I0]~1'0 158, Japan h Department ofPhwtc*. Osal~a ('ttl ~_ m~er~itv. 03al~a 558. Japan ' Graduate School of S~tence and Technoh)gv. Kobe t m~ersttt. Kohe 65 7. Japan Department o! Ph)sic s. ToLl o Institute o/lee hnologv. Tol~vo 152. Japan Fac ult~ of Liberal Iris 7 ezuKavama ( tll~etSltl. Vata 631. Japan

The process e + e --, e ÷ e -p + In-has been studied in single-tag and double-tag configurations using the TOPAZ detector at TRIS-TAN. The data correspond to the integrated luminosity of 45.3 pb-~ at center-of-mass energies ranging from 52 to 61.4 GeV. The observed events in both configurations have shown a good agreement with QED predictions in order at 4. Although the AMY group reported an excess ofe+e -~e+e-p.+~t -events in double-tag mode at low muon invariant mass region less than 1.0 GeV/c 2, we did not observe such excess in our data.

We have carried out an inclusive measurement of K 0 (K 0 ) production in twophoton processes at TRISTAN. The mean √ s was 58 GeV and the integrated luminosity was 199 pb −1 . High-statistics K s samples were obtained under such conditions as no-, anti-electron, and remnant-jet tags. The remnant-jet tag, in particular, allowed us, for the first time, to measure the cross sections separately for the resolved-photon and direct processes.

The mechanism of baryon-anti-baryon pair production in e q e y annihilation into hadrons has been studied using the TOPAZ detector at the TRISTAN e q e y collider at an average center-of-mass energy of 58 GeV. The distributions of 1 E-mail:watanabe@hp.phys.titech.ac.jp 0370-2693r98r$ -see front matter q 1998 Published by Elsevier Science B.V. All rights reserved.

Excited leptons, e*, I1" and z*, have bccu searched for with the TOPAZ detector at TRISTAN c÷e -collidcr in the energy region ,v.~= 52-60.8 GeV. e* and p* have been searched for in the single production process, e+e -~+~-~', and the pair production process, e-e--,~ +~-7-f, where ~ stands for e or ~. c* has also bccn searchcd for in the processes e +e---,e'! (c) (quasi-real Compton scattering) and e-e-~T~'. z* has been searched for in the z*-pair production process, e+e " ~+x 7qt. No evidence for the production of excited leptons has been found, and new limits on e*, p* and z* production are set.

The strong coupling constant as was determined from analyses of the thrust, heavy jet mass and, differential 2-jet rate, using e+e -hadronic events at x/'g = 58 GeV with the TOPAZ detector at TRISTAN. The NLLjet Monte Carlo simulation (NLLjet) and analytic formulae based on resummation up to the next-to-leading logarithms combined with O(a 2) calculations were used to evaluate C~s. The averaged as values at Q2 = (58 GeV) 2 from the analyses are as = 0.125 4-0.009 for NLLjet and as = 0.132 4-0.008 for the resummed analytic formulae.

We have studied open charm production in γγ collisions with the TOPAZ detector at the TRISTAN e + e − collider. In this study, charm quarks were identified by electrons (and positrons) from semi-leptonic decays of charmed hadrons. The data corresponded to an integrated luminosity of 95.3 pb −1 at a center-of-mass energy of 58 GeV. The results are presented as the cross sections of inclusive electron production in γγ collisions with an anti-tag condition, as well as the subprocess cross sections, which correspond to resolved-photon processes. The latter were measured by using a sub-sample with remnant jets. A comparison with various theoretical predictions based on direct and resolved-photon processes showed that our data prefer that with relatively large gluon contents in a photon at small x(x ≤ 0.1), with the next-to-leading order correction, and with a charm-quark mass of 1.3 GeV.

We have measured the cross section for gammagamma production with the TOPAZ detector in the energy region &surd;s=50.0-61.4 GeV. The observed cross section for gammagamma production integrated over |costheta| <= 0.77 is 50.2+/-0.8+/-2.2 pb at =57.6 GeV and the ratio of this value to the QED prediction is 1.01+/-0.02+/-0.04. The angular distribution is in good agreement with the QED predictions,

The shape of jets produced in (quasi-) real photon-photon collisions as well as in e + e − annihilation process has been studied with a cone jet finding algorithm, using the data taken with the TOPAZ detector at the TRISTAN e + e − collider at an average center-of-mass energy ( √ s ee ) of 58 GeV. The results are presented in terms of the jet width as a function of the jet transverse energy (E jet T ) as well as a scaled transverse jet energy, x T (=2·E jet T / √ s). The jet width narrows as E jet T increases; however, at the same value of E jet T the jet width in γγ collisions at TRISTAN is significantly narrower than that in γp collisions at HERA. By comparing our results with the data in other reactions, it has been shown that the jet width in γγ, γp, pp collisions as well as the e + e − annihilation process has an approximate scaling behavior as a function of x T . * To be published in Phys. Lett. B.

We have collected 122 multi-hadronic inclusive muon events with the TOPAZ detector at (~'J) = 58.27 GeV with fL¢ dt = 40.61 pb-1. From this event sample we derived the differential cross section for B-hadron productions and determined B-hadron forward-backward asymmetry (Ab6) to be Ab6 = --0.71 + 0.34 (stat) +_o:07 (syst). A fit to the differential cross section, after correcting for the effect of B°l~ ° mixing, yielded the axial-vector coupling constant of the b-quark (ab) : ab = -1.79_+° 1334 (stat) +0.15 _o.14(syst). We also set a 90% confidence level limit of X<0.37 on the B°fi ° mixing parameter.

We report new results obtained in calibrations of superheated liquid droplet detectors used in dark matter searches with different radiation sources (n,α,γ). In particular, detectors were spiked with alpha-emitters located inside and outside the droplets. It is shown that the responses are different, depending on whether alpha particles or recoil nuclei create the signals. The energy thresholds for α-emitters are compared with test beam measurements using mono-energetic neutrons, as well as with theoretical predictions. Finally a model is presented which describes how the observed intensities of particle induced acoustic signals can be related to the dynamics of bubble growth in superheated liquids. An improved understanding of the bubble dynamics is an important first step in obtaining better discrimination between particle types interacting in detectors of this kind. † present address:

As photodisintegration of deuterons mimics the disintegration of deuterons by neutrinos, the accurate measurement of the radioactivity from thorium and uranium decay chains in the heavy water in the Sudbury Neutrino Observatory (SNO) is essential for the determination of the total solar neutrino flux. A radium assay technique of the required sensitivity is described that uses hydrous titanium oxide (HTiO) adsorbent on a filtration membrane together with a β − α delayed coincidence counting system. For a 200 tonne assay the detection limit for 232 Th is a concentration of ∼ 3 × 10 −16 g Th/g water and for 238 U of ∼ 3 × 10 −16 g U/g water. Results of assays of both the heavy and light water carried out during the first two years of data collection of SNO are presented.

The technique used at the Sudbury Neutrino Observatory (SNO) to measure the concentration of 222 Rn in water is described. Water from the SNO detector is passed through a vacuum degasser (in the light water system) or a membrane contact degasser (in the heavy water system) where dissolved gases, including radon, are liberated. The degasser is connected to a vacuum system which collects the radon on a cold trap and removes most other gases, such as water vapor and N 2 : After roughly 0:5 tonnes of H 2 O or 6 tonnes of D 2 O have been sampled, the accumulated radon is transferred to a Lucas cell. The cell is mounted on a photomultiplier tube which detects the a-particles from the decay of 222 Rn and its progeny. The overall degassing and concentration efficiency is about 38% and the single-a counting efficiency is approximately 75%. The sensitivity of the radon assay system for D 2 O is equivalent to B3 Â 10 À15 g U=g water. The radon concentration in both the H 2 O and D 2 O is sufficiently low that the rate of background events from U-chain elements is a small fraction of the interaction rate of solar neutrinos by the neutral current reaction. r (I. Levine).