Showing papers by "Jun Lu published in 1995"
TL;DR: In this paper, the existence of the top quark was established using a data sample of collisions at the Fermilab National Ensemble (CDF) collected with the Collider Detector.
Abstract: We establish the existence of the top quark using a $67{\mathrm{pb}}^{\ensuremath{-}1}$ data sample of $\overline{p}p$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\mathrm{TeV}$ collected with the Collider Detector at Fermilab (CDF). Employing techniques similar to those we previously published, we observe a signal consistent with $t\overline{t}$ decay to $\mathrm{WWb}\overline{b}$, but inconsistent with the background prediction by $4.8\ensuremath{\sigma}$. Additional evidence for the top quark is provided by a peak in the reconstructed mass distribution. We measure the top quark mass to be $176\ifmmode\pm\else\textpm\fi{}8(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}10(\mathrm{syst})\mathrm{GeV}{/c}^{2}$, and the $t\overline{t}$ production cross section to be ${6.8}_{\ensuremath{-}2.4}^{+3.6}\mathrm{pb}$.
1,022 citations
TL;DR: In this paper, the authors presented a 95% confidence level upper limit on the production cross section times branching ratio of 2' decaying into dielectrons as a function of the 2' mass.
Abstract: We have searched for heavy neutral gauge bosons (2’) in jjp collisions at Js = 1.8 TeV. The data were obtained using the CDF detector during 19921993 run corresponding to an integrated luminosity of 19.7f0.7 pb-‘. We present a 95% confidence level upper limit on the production cross section times branching ratio of 2’ decaying into dielectrons as a function of 2’ mass. Assuming Standard Model coupling strengths, we exclude a 2’ with mass less than 505 GeV/c 2. We also present lower mass limits for 2’ bosons from & models and the Alternative Left-Right Model. PACS numbers: 13.85.Rm, 12.15.Cc, 14.80.Er Neutral gauge bosons in addition to the 2’ are expected in many extensions of the Standard Model [l]. These models typically specify the strengths of the couplings of such bosons to quarks and leptons but make no mass predictions [2]. In up collisions, 2’ bosons may be observed directly via their decay to lepton pairs. Observation of a 2’ boson would provide dramatic evidence for physics beyond the Standard Model. To date there is no experimental evidence for the existence of any 2’ [3]. The current experimental 2’ mass limit Mzt > 412 GeV/c2 (95% C.L.) was established by the CDF collaboration [4] with the assumption that the coupling strengths of the 2’ to quarks and leptons were the same as those for the Standard Model (SM) 2’. This result was based upon data collected during the 1988-89 run with an integrated luminosity of 4 pb-’ and used both the dielectron [5] and dimuon decay modes. We report an extension of this search using 19.7 pb* of integrated luminosity from the 1992-93 run. Results reported here are obtained using only the dielectron decay mode. We present a 95% confidence level upper limit on the production cross section times branching ratio of 2’ decaying into dielectrons (g(Z) . B(Z’ + ee)). Mass limits are 5 again derived assuming SM coupling strengths. In addition, we present 2’ mass limits using several different theoretical models based on the Es symmetry group [6][‘7] and one limit based upon an Alternative Left-Right Model [8]. The CDF detector has been described in detail elsewhere [9]. We give a brief description of the components relevant to this analysis. Momenta of charged particles are measured in the Central Tracking Chamber (CTC), which is immersed in a 1.4 T axial magnetic field. Outside the CTC, electromagnetic and hadronic calorimeters are arranged in a projective tower geometry. There are three separate pseudorapidity (7) regions of calorimeters, central, end-plug, and forward, where 7 = ln(tan $) and 0 is the polar angle with respect to the direction of the proton beam. Each region has an electromagnetic calorimeter and behind it a hadronic calorimeter. For this analysis we use electrons detected in the central (CEM) or end-plug (PEM) regions. The CEM covers ]q] 9 GeV or an energy cluster in the PEM with ET > 20 GeV. If the cluster was in the CEM the trigger also required a coincidence with a track of transverse momentum PT > 9.2 GeV/c. In addition, the trigger required that the ratio of hadronic to electromagnetic energy (HAD/EM) in the trigger cluster be less than 12.5%. For electrons with 25 150 GeV), the energy deposited
112 citations
TL;DR: In this article, the first direct measurement of the meson differential cross section was made using a sample of $19.7$ p${\mathrm{b}}^{--1}$ accumulated by the Collider Detector at Fermilab.
Abstract: This paper presents the first direct measurement of the $B$ meson differential cross section $d\ensuremath{\sigma}{/dp}_{T}$ in $p\overline{p}$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8$ TeV using a sample of $19.3\ifmmode\pm\else\textpm\fi{}0.7$ p${\mathrm{b}}^{--1}$ accumulated by the Collider Detector at Fermilab. The cross section is measured in the central rapidity region $|y|l1$ for ${p}_{T}\left(B\right)g6.0$ GeV $/c$ by fully reconstructing the $B$ meson decays ${B}^{+}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{+}$ and ${B}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{*0}\left(892\right)$, where $J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ and ${K}^{*0}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$. A comparison is made to the theoretical QCD prediction calculated at next-to-leading order.
81 citations
01 Sep 1995-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: The data indicate that a circadian clock regulates ocular sensitivity to light and that melatonin may mediate some or all of this effect, and suggest a central site rather than a direct effect of the hormone in the eye.
Abstract: Visual and circadian function are integrally related in birds, but the precise nature of their interaction is unknown. The present study determined whether visual sensitivity measured electroretinographically (ERG) in 7-week-old cockerels varies over the time of day, whether this rhythm persists in constant darkness (DD) and whether exogenous melatonin affects this ERG rhythmicity. ERG b-wave amplitude was rhythmic in LD and persisted in DD with peak amplitude during mid- to late afternoon in LD and mid-subjective day in DD, indicating that the ERG rhythm is endogenously generated. No daily or circadian variation in a-wave amplitude was observed, and ERG component latency and durations were not rhythmic. Intramuscular injection of 10 μg/kg melatonin at ZT10 in LD significantly decreased b-wave amplitude but had no effect on a-wave. Intraocular injection of 600 pg melatonin, however, had no effect on any aspect of the ERG. These data indicate that a circadian clock regulates ocular sensitivity to light and that melatonin may mediate some or all of this effect. The level at which melatonin modulates retinal sensitivity is not known, but the present data suggest a central site rather than a direct effect of the hormone in the eye.
53 citations
52 citations
TL;DR: A measurement of the W boson mass is presented using data collected by the D0 experiment at the Fermilab Tevatron during 1994--1995 and W bosons are identified by their decays to $e\ensuremath{
u}$ final states.
Abstract: This paper presents a measurement of the mass of the W boson using data collected with the CDF detector during the 1992--1993 collider run at the Fermilab Tevatron. A fit to the transverse mass spectrum of a sample of 3268 W\ensuremath{\rightarrow}\ensuremath{\mu}\ensuremath{
u} events recorded in an integrated luminosity of 19.7 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ gives ${\mathit{M}}_{\mathit{W}}^{\mathrm{\ensuremath{\mu}}}$=80.310\ifmmode\pm\else\textpm\fi{}0.205 (stat)\ifmmode\pm\else\textpm\fi{}0.130 (syst) GeV/${\mathit{c}}^{2}$. A fit to the transverse mass spectrum of a sample of 5718 W\ensuremath{\rightarrow}e\ensuremath{
u} events recorded in 18.2 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ gives ${\mathit{M}}_{\mathit{W}}^{\mathit{e}}$=80.490\ifmmode\pm\else\textpm\fi{}0.145 (stat)\ifmmode\pm\else\textpm\fi{}0.175 (syst) GeV/${\mathit{c}}^{2}$. Combining the muon and electron results, accounting for correlated uncertainties, yields ${\mathit{M}}_{\mathit{W}}$=80.410\ifmmode\pm\else\textpm\fi{}0.180 GeV/${\mathit{c}}^{2}$.
46 citations
TL;DR: In this article, the authors used 19 pb**-1 of data collected with the Collider Detector at Fermilab to search for new particles decaying to dijets.
Abstract: We have used 19 pb**-1 of data collected with the Collider Detector at Fermilab to search for new particles decaying to dijets. We exclude at 95% confidence level models containing the following new particles: axigluons with mass between 200 and 870 GeV, excited quarks with mass between 80 and 570 GeV, and color octet technirhos with mass between 320 and 480 GeV.
41 citations
TL;DR: In this article, the authors report on a study of [ital W]- photon production in approximately 20 pb[sup [minus]1] of [ITAL p][minus][ital [bar p] collisions at [radical][ital s]=1.8 TeV recorded with the Collider Detector at Fermilab.
Abstract: We report on a study of [ital W]+ photon production in approximately 20 pb[sup [minus]1] of [ital p][minus][ital [bar p]] collisions at [radical][ital s]=1.8 TeV recorded with the Collider Detector at Fermilab. Our results are in good agreement with standard model expectations and are used to obtain limits on anomalous [ital CP]-conserving [ital WW][gamma] couplings of [minus]2.3[lt][Delta][kappa][lt]2.2 for [lambda]=0 and [minus]0.7[lt][lambda][lt]0.7 for [Delta][kappa]=0 at 95% C.L. We obtain the same limits for [ital CP]-violating couplings. These results provide limits on the higher-order electromagnetic moments of the [ital W] boson of 0.8[lt][ital g][sub [ital W]][lt]3.1 for [ital q][sup [ital e]][sub [ital W]]=1 and [minus]0.6[lt][ital q][sup [ital e]][sub [ital W]][lt]2.7 for [ital g][sub [ital W]]=2 at 95% C.L.
39 citations
TL;DR: In this paper, the authors report on measurements of the $\ensuremath{\Upsilon}(1S)$, ''enuremath{1S}(2S), and ''ensuremath{3S'' (3S)$ differential, and integrated cross sections in $p\overline{p}$ collisions at $\sqrt{s}=1.8$ TeV using a sample of 16.6 ${\mathrm{pb}}^{\ensureMath{-}1}$ collected by the Collider Detector at F
Abstract: We report on measurements of the $\ensuremath{\Upsilon}(1S)$, $\ensuremath{\Upsilon}(2S)$, and $\ensuremath{\Upsilon}(3S)$ differential, ${(\frac{{d}^{2}\ensuremath{\sigma}}{d{P}_{t}\mathrm{dy}})}_{y=0}$, and integrated cross sections in $p\overline{p}$ collisions at $\sqrt{s}=1.8$ TeV using a sample of 16.6 \ifmmode\pm\else\textpm\fi{} 0.6 ${\mathrm{pb}}^{\ensuremath{-}1}$ collected by the Collider Detector at Fermilab. The three resonances were reconstructed through the decay $\ensuremath{\Upsilon}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$. Comparison is made to a leading order QCD prediction.
39 citations
TL;DR: In this paper, the authors measured the charge asymmetry using 19 039 [ital W] decays recorded by the Collider Detector at Fermilab during the 1992--93 run of the Tevatron Collider.
Abstract: Charge asymmetry has been measured using 19 039 [ital W] decays recorded by the Collider Detector at Fermilab during the 1992--93 run of the Tevatron Collider. The asymmetry is sensitive to the ratio of [ital d] and [ital u] quark distributions to [ital x][lt]0.01 at [ital Q][sup 2][approx][ital M][sup 2][sub [ital W]], where nonperturbative effects are minimal. It is found that of the two current sets of parton distributions, those of Martin, Roberts, and Stirling are favored over the sets most recently produced by the CTEQ Collaboration. The [ital W] asymmetry data provide stronger constraints on [ital d]/[ital u] ratio than the recent measurements of [ital F][sub 2][sup [mu][ital n]]/[ital F][sub 2][sup [mu][ital p]], which are limited by uncertainties originating from deuteron corrections.
32 citations
TL;DR: In this paper, simple fragments of transition metal 1,2-bidentate thiolates, the so-called building blocks of the general compositions ML3, ML2, ML, M(O)L 2, ML 2L′, MLL′, etc. have been proposed to constitute the di-, tri-and tetranuclear complexes concerned in this review.
Abstract: Simple fragments of transition metal 1,2-bidentate thiolates, the so-called building blocks of the general compositions ML3, ML2, ML, M(O)L2, ML2L′, MLL′, etc. have been proposed to constitute the di-, tri- and tetranuclear complexes concerned in this review. Structureal regularities and characteristics have been discussed and summarized according to the thiolato ligands edt and pdt, bdt and tdt, mp, and mpo, and mpp, respectively.
TL;DR: In this article, the authors have searched for new heavy, heavy, charged bosons through the decay of {ital W}{prime}{r_arrow}{ital e}{nu} in {ital pp}{ovr bar} collisions at {radical}{ital s}=1.8 TeV.
Abstract: We have searched for new, heavy, charged bosons {ital W}{prime} through the decay {ital W}{prime}{r_arrow}{ital e}{nu} in {ital pp}{ovr bar} collisions at {radical}{ital s}=1.8 TeV. The data used in the search represent 19.7 pb{sup --1}collected by the Collider Detector at Fermilab. Limits are placed on {sigma}{ital B}({ital pp}{ovr bar}{r_arrow}{ital W}{prime}{r_arrow}{ital e}{nu}) as a function of {ital M}{sub {ital W}{prime}}. Assuming standard couplings of the {ital W}{prime} to fermions, we establish the limit {ital M}{sub {ital W}{prime}}{gt}652 GeV/{ital c}{sup 2} (95% C.L.).
TL;DR: In this paper, the authors report limits on anomalous [ital ZZ][gamma] and ] couplings derived from an analysis of [ital z]-photon production based upon approximately 20pb[sup [minus]1] of the [bar p] collision data recorded by the Collider Detector at Fermilab.
Abstract: We report limits on anomalous [ital ZZ][gamma] and [ital Z][gamma][gamma] couplings derived from an analysis of [ital Z]+photon production based upon approximately 20pb[sup [minus]1] of the [bar p] collision data recorded by the Collider Detector at Fermilab. We observe good agreement with the standard model expectation that all [ital Z][gamma] couplings are zero. Confidence level intervals for individual couplings and contours for pairs of [ital CP]-conserving/violating [ital ZZ][gamma] and [ital Z][gamma][gamma] couplings are presented.
TL;DR: In this paper, measurements of the longitudinal polarization fractions in the decays of the decay chain were reported, using data collected with the Collider Detector at Fermilab, and a sample of 65{plus_minus}10{ital B}{sub {ital d}}{r_arrow}{ital d}/{psi}{ital K}{sup *0} was used to obtain a longitudinal polarization fraction of 0.65{plus-minus}0.10(stat, plus-minus)0.21(stat).
Abstract: This Letter reports on measurements of the longitudinal polarization fractions in the decays {ital B}{sub {ital d}}{r_arrow}{ital J}/{psi}{ital K}{sup *0} and {ital B}{sub {ital s}}{r_arrow}{ital J}/{psi}{phi} using data collected with the Collider Detector at Fermilab. {ital B}{sub {ital d}} mesons are reconstructed through the decay chain {ital B}{sub {ital d}}{r_arrow}{ital J}/{psi}{ital K}*, {ital J}/{psi}{r_arrow}{mu}{sup +}{mu}{sup {minus}}, {ital K}{sup *0}{r_arrow}{ital K}{sup +}{pi}{sup {minus}}. A sample of 65{plus_minus}10{ital B}{sub {ital d}} events is used to obtain a longitudinal polarization fraction of {Gamma}{sub {ital L}}/{Gamma}=0.65{plus_minus}0.10(stat){plus_minus}0.04(syst). {ital B}{sub {ital s}} mesons are reconstructed through the decay chain {ital B}{sub {ital s}}{r_arrow}{ital J}/{psi}{phi}, {ital J}/{psi}{r_arrow}{mu}{sup +}{mu}{sup {minus}}, {phi}{r_arrow}{ital K}{sup +}{ital K}{sup {minus}}. A sample of 19{plus_minus}5{ital B}{sub {ital s}} events is used to obtain the result {Gamma}{sub {ital L}}/{Gamma}=0.56{plus_minus}0.21(stat){sub {minus}0.04}{sup +0.02}(syst). Copyright {ital 1995} {ital The} {ital American} {ital Physical} {ital Society}.
TL;DR: In this article, the orientation of the films was strongly influenced by the substrate pre-treatment, and the orientation was determined from the transmission electron microscopy (TEM) investigations from various orientational relationships between the Cu2O islands and substrate.
TL;DR: Evidence is found for a $b-quark content in their jets to the extent expected from top decay, and larger than expected for background processes, for events with four or more jets.
Abstract: We present a study of W+multijet events that compares the kinematics of the observed events with expectations from direct QCD W+jet production and from production and decay of top quark pairs. The data were collected in the 1992--93 run with the Collider Detector at Fermilab (CDF) from 19.3 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ of proton-antiproton collisions at \ensuremath{\surd}s =1.8 TeV. A W+\ensuremath{\ge}2 jet sample and a W+\ensuremath{\ge}3 jet sample are selected with the requirement that at least the two or three jets have energy transverse with respect to the beam axis in excess of 20 GeV. The jet energy distributions for the W+\ensuremath{\ge}2 jet sample agree well with the predictions of direct QCD W production. From the W+\ensuremath{\ge}3 jet events, a ``signal sample'' with an improved ratio of tt\ifmmode\bar\else\textasciimacron\fi{} to QCD produced W events is selected by requiring each jet to be emitted centrally in the event center of mass frame. This sample contains 14 events with unusually hard jet ${\mathit{E}}_{\mathit{T}}$ distributions not well described by expectations for jets from direct QCD W production and other background processes. Using expected jet ${\mathit{E}}_{\mathit{T}}$ distributions, a relative likelihood is defined and used to determine if an event is more consistent with the decay of tt\ifmmode\bar\else\textasciimacron\fi{} pairs, with ${\mathit{M}}_{\mathrm{top}}$=170 GeV/${\mathit{c}}^{2}$, than with direct QCD W production. Eight of the 14 signal sample events are found to be more consistent with top-quark than direct QCD W production, while only 1.7 such top-quark--like events are expected in the absence of tt\ifmmode\bar\else\textasciimacron\fi{}.The probability that the observation is due to an upward fluctuation of the number of background events is found to be 0.8%. The robustness of the result was tested by varying the cuts defining the signal sample, and the largest probability for such a fluctuation found was 1.9%. Good agreement in the jet spectra is obtained if jet production from tt\ifmmode\bar\else\textasciimacron\fi{} pair decays is included. For those events kinematically more consistent with tt\ifmmode\bar\else\textasciimacron\fi{} we find evidence for a b-quark content in their jets to the extent expected from top quark decay, and larger than expected for background processes. For events with four or more jets, the discrepancy with the predicted jet distributions from direct QCD W production, and the associated excess of b-quark content, is more pronounced.
TL;DR: In this article, the properties of high-mass multijet events produced at the Fermilab proton-antiproton collider are compared with leading order QCD matrix element predictions, QCD parton shower Monte Carlo predictions, and the predictions from a model in which events are distributed uniformly over the available multibody phase space.
Abstract: The properties of high-mass multijet events produced at the Fermilab proton-antiproton collider are compared with leading order QCD matrix element predictions, QCD parton shower Monte Carlo predictions, and the predictions from a model in which events are distributed uniformly over the available multibody phase space. Multijet distributions corresponding to (4{ital N}{minus}4) variables that span the {ital N}-body parameter space are found to be well described by the QCD calculations for inclusive three-jet, four-jet, and five-jet events. The agreement between data, QCD matrix element calculations, and QCD parton shower Monte Carlo predictions suggests that 2{r_arrow}2 scattering plus gluon radiation provides a good first approximation to the full LO QCD matrix element for events with three, four, or even five jets in the final state. {copyright} {ital 1996 The American Physical Society.}
TL;DR: The lifetime of the {ital B}{sub {ital s}} meson is measured using the semileptonic decay of the Tournaisian meson using a data sample collected by the Collider Detector at Fermilab during 1992--1993.
Abstract: The lifetime of the {ital B}{sub {ital s}} meson is measured using the semileptonic decay {ital B}{sub {ital s}}{r_arrow}{ital D}{sub {ital s}}{sup {minus}}l{sup +}{nu}{ital X}. The data sample consists of 19.3 pb{sup {minus}1} of {ital p{bar p}} collisions at {radical}{ital s}=1.8 TeV collected by the Collider Detector at Fermilab during 1992--1993. There are 76{plus_minus}8 l{sup +}{ital D}{sub {ital s}}{sup {minus}} signal events where the {ital D}{sub {ital s}} is identified via the decay {ital D}{sub {ital s}}{sup {minus}}{r_arrow}{phi}{pi}{sup {minus}}, {phi}{r_arrow}{ital K}{sup +}{ital K}{sup {minus}}. Using these events, the {ital B}{sub {ital s}} meson lifetime is determined to be {tau}{sub {ital s}}=1.42{sub {minus}0.23}{sup +0.27}(stat){plus_minus}0.11(syst) ps. A measurement of the {ital B}{sub {ital s}} lifetime in a low statistics sample of exclusive {ital B}{sub {ital s}}{r_arrow}{ital J}/{psi}{phi} decays is also presented in this paper.
TL;DR: The observed jet transverse momentum distributions for threeand fourjet events discriminate between the matrix element and parton shower predictions, the Ilata favoring the matrixelement calculation.
Abstract: The properties of two-, three-, four-, five-, and six-jet events with multijet masses > 600 GeV/c’ are compared with QCD predictions. The shapes of the multijet-mass and leadingjet-angular distributions are approximately independent of jet multiplicity and are well IL,scribed by the NJETS matrix element calculation and the HERWIG parton shower lloutr Carlo predictions. The observed jet transverse momentum distributions for threeand fourjet events discriminate between the matrix element and parton shower predictions, the Ilata favoring the matrix element calculation.
TL;DR: In this article, a sample of {ital W}+jet events collected with the Collider Detector at Fermilab (CDF) in {ital pp} collisions at {ital s}=1.8 TeV to study {ital tt} production was analyzed and a simple kinematical variable H, defined as the scalar sum of the transverse energies of the lepton, neutrino and jets, was employed.
Abstract: We analyze a sample of {ital W}+jet events collected with the Collider Detector at Fermilab (CDF) in {ital pp} collisions at {radical}{ital s}=1.8 TeV to study {ital tt} production. We employ a simple kinematical variable H, defined as the scalar sum of the transverse energies of the lepton, neutrino, and jets. For events with a {ital W} boson and four or more jets, the shape of the H distribution deviates by 3.8 standard deviations from that expected from known backgrounds to {ital tt} production. However, this distribution agrees well with a linear combination of background and {ital tt} events, the agreement being best for a top mass of 180 GeV/{ital c}{sup 2}. {copyright} {ital 1995} {ital The} {ital American} {ital Physical} {ital Society}.
TL;DR: A kinematic technique is used to distinguish top quark pair production from background in {ital p{bar p}} collisions at {radical}{ital s}=1.8 TeV, and results are interpreted as evidence that most of the selected events are from {ital t{bar t}} decay.
Abstract: We have used a kinematic technique to distinguish top quark pair production from background in pp\ifmmode\bar\else\textasciimacron\fi{} collisions at \ensuremath{\surd}s=1.8 TeV, applied to 67 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ of data. We define a sample of W+\ensuremath{\ge}3 jet events in which the jets are produced at large angles relative to the incident beams. In this sample, we find an excess of events with large jet transverse energies relative to expectations from background. The excess is consistent with top quark production; a large fraction of events in this kinematic region contains b jets. We interpret these results as evidence that most of the selected events are from tt\ifmmode\bar\else\textasciimacron\fi{} decay.
TL;DR: In this article, the lifetime of the meson was measured using the exclusive decay mode, where the decay mode was used to measure the lifetime for the B = 0.12$ signal events.
Abstract: The lifetime of the ${B}_{s}^{0}$ meson is measured using the exclusive decay mode ${B}_{s}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\varphi}$, where $J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ and $\ensuremath{\varphi}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}$. The data sample consists of $110{\mathrm{pb}}^{\ensuremath{-}1}$ of $p\overline{p}$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\phantom{\rule{0ex}{0ex}}\mathrm{TeV}$, collected by the CDF detector at the Fermilab Tevatron collider during 1992--1995. We find $58\ifmmode\pm\else\textpm\fi{}12$ signal events, and the ${B}_{s}^{0}$ meson lifetime is determined to be ${\ensuremath{\tau}}_{{B}_{s}^{0}}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.34}_{\ensuremath{-}0.19}^{+0.23}(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.05(\mathrm{syst})$ ps. This result is consistent with previous measurements of the ${B}_{s}^{0}$, ${B}^{+}$, and ${B}_{d}^{0}$ meson lifetimes and with theoretical predictions.
TL;DR: In this paper, a home built DNP magic-angle-spinning (MAS) NMR spectrometer operates at a field strength of 1.9 T and the highest DNP enhancement factor of synthetic diamonds came near to 103.
Abstract: Four Ib-type synthetic diamond crystals were studied by dynamic nuclear polarization (DNP)-enhanced high resolution solid state13C nuclear magnetic resonance (NMR) spectroscopy. The home built DNP magic-angle-spinning (MAS) NMR spectrometer operates at a field strength of 1.9 T and the highest DNP enhancement factor of synthetic diamonds came near to 103. Comparing with Ib-type natural diamonds, the13C NMR linewidths of synthetic diamonds in static spectra are broader. The13C spin-lattice relaxation time and DNP polarization time of synthetic diamond are shorter than those of Ib-type natural diamond. From the hyperfine structure of the DNP enhancement curve, four kinds of nitrogen-centred free radicals could be identified in synthetic diamond.
TL;DR: In this article, the synthesis of transition metal clusters involving bridging sulfido ligands is discussed. And the potential application of the "unit construction" schemes in synthesis of other bridging ligands are presented.
Abstract: Designed synthesis for some transition metal clusters involving bridging-sulfido ligands is reviewed. The basic concept with the use of reactive fragments as building blocks is described. It is shown that the sulfido ligands with lone-pair electrons and the unsaturated coordination sites play important roles in this rational synthesis. The relationship between the metallic coordination types of the sulfido ligands and their assembling activity in the compounds is summarized. Examples of the six kinds of “unit construction” with reactive fragments as building blocks are shown, indicating clearly that the “unit construction” is a reasonable way in the synthesis of transition metal clusters involving bridging sulfido ligands. Finally, the potential application of the “unit construction” schemes in the synthesis of transition metal clusters involving other bridging ligands is presented.