We report the first measurement of the \(Q^2\) distribution of \(X(3915)\) produced by single-tag two-photon interactions. The decay mode used is \(X(3915) \rightarrow J/\psi\omega\). The covered ...\(Q^2\) region is from 1.5 (GeV/\(c\))\(^2\) to 10.0 (GeV/\(c\))\(^2\). We observe \(7.9\pm 3.1({\rm stat.})\pm 1.5({\rm syst.})\) events, where we expect \(4.1\pm 0.7\) events based on the \(Q^2=0\) result from the no-tag two-photon process, extrapolated to higher \(Q^2\) region using the \(c\bar{c}\) model of Schuler, Berends, and van Gulik. The shape of the distribution is also consistent with this model; we note that statistical uncertainties are large.
The aim of the study was to determine the frequency of the metabolic syndrome in a specific group of people.
The ATP III criteria were used to identify the metabolic syndrome in a group of 1,410 ...corporate executives belonging to a specialist health and fitness company in South Africa.
Using three criteria as specified by the ATP III panel, 31% of this group of corporate executives fulfilled the criteria for the diagnosis of the metabolic syndrome. In a small subset of black executives, a similar finding was obtained. Another one-third of the executives had two criteria of the metabolic syndrome.
The metabolic syndrome was common in a group of corporate executives.
We present a search for the baryon number \(B\) and lepton number \(L\) violating decays \(\tau^- \rightarrow \Lambda \pi^-\) and \(\tau^- \rightarrow \bar{\Lambda} \pi^-\) produced from the ...\(e^+e^-\to \tau^+\tau^-\) process, using a 364 fb\(^{-1}\) data sample collected by the Belle~II experiment at the SuperKEKB collider. No evidence of signal is found in either decay mode, which have \(|\Delta(B-L)|\) equal to \(2\) and \(0\), respectively. Upper limits at 90\% credibility level on the branching fractions of \(\tau^- \rightarrow \Lambda\pi^-\) and \(\tau^- \rightarrow \bar{\Lambda}\pi^-\) are determined to be \(4.7 \times 10^{-8}\) and \(4.3 \times 10^{-8}\), respectively.
We present a study of \(\Xi_{c}^{0}\to\Xi^{0}\pi^{0}\), \(\Xi_{c}^{0}\to\Xi^{0}\eta\), and \(\Xi_{c}^{0}\to\Xi^{0}\eta^{\prime}\) decays using the Belle and Belle~II data samples, which have ...integrated luminosities of 980~\(\mathrm{fb}^{-1}\) and 426~\(\mathrm{fb}^{-1}\), respectively. We measure the following relative branching fractions $${\cal B}(\Xi_{c}^{0}\to\Xi^{0}\pi^{0})/{\cal B}(\Xi_{c}^{0}\to\Xi^{-}\pi^{+}) = 0.48 \pm 0.02 ({\rm stat}) \pm 0.03 ({\rm syst}) ,$$ $${\cal B}(\Xi_{c}^{0}\to\Xi^{0}\eta)/{\cal B}(\Xi_{c}^{0}\to\Xi^{-}\pi^{+}) = 0.11 \pm 0.01 ({\rm stat}) \pm 0.01 ({\rm syst}) ,$$ $${\cal B}(\Xi_{c}^{0}\to\Xi^{0}\eta^{\prime})/{\cal B}(\Xi_{c}^{0}\to\Xi^{-}\pi^{+}) = 0.08 \pm 0.02 ({\rm stat}) \pm 0.01 ({\rm syst}) $$ for the first time, where the uncertainties are statistical (\(\rm stat\)) and systematic (\(\rm syst\)). By multiplying by the branching fraction of the normalization mode, \({\mathcal B}(\Xi_{c}^{0}\to\Xi^{-}\pi^{+})\), we obtain the following absolute branching fraction results \((6.9 \pm 0.3 ({\rm stat}) \pm 0.5 ({\rm syst}) \pm 1.3 ({\rm norm})) \times 10^{-3}\), \((1.6 \pm 0.2 ({\rm stat}) \pm 0.2 ({\rm syst}) \pm 0.3 ({\rm norm})) \times 10^{-3}\), and \((1.2 \pm 0.3 ({\rm stat}) \pm 0.1 ({\rm syst}) \pm 0.2 ({\rm norm})) \times 10^{-3}\), for \(\Xi_{c}^{0}\) decays to \(\Xi^{0}\pi^{0}\), \(\Xi^{0}\eta\), and \(\Xi^{0}\eta^{\prime}\) final states, respectively. The third errors are from the uncertainty on \({\mathcal B}(\Xi_{c}^{0}\to\Xi^{-}\pi^{+})\). The asymmetry parameter for \(\Xi_{c}^{0}\to\Xi^{0}\pi^{0}\) is measured to be \(\alpha(\Xi_{c}^{0}\to\Xi^{0}\pi^{0}) = -0.90\pm0.15({\rm stat})\pm0.23({\rm syst})\).
We report a measurement of the \(e^+e^- \to \pi^+\pi^-\pi^0\) cross section in the energy range from 0.62 to 3.50 GeV using an initial-state radiation technique. We use an \(e^+e^-\) data sample ...corresponding to 191 \(\text{fb}^{-1}\) of integrated luminosity, collected at a center-of-mass energy at or near the \(\Upsilon{(4S)}\) resonance with the Belle II detector at the SuperKEKB collider. Signal yields are extracted by fitting the two-photon mass distribution in \(e^+e^- \to \pi^+\pi^-\pi^0\gamma\) events, which involve a \(\pi^0 \to \gamma\gamma\) decay and an energetic photon radiated from the initial state. Signal efficiency corrections with an accuracy of 1.6% are obtained from several control data samples. The uncertainty on the cross section at the \(\omega\) and \(\phi\) resonances is dominated by the systematic uncertainty of 2.2%. The resulting cross sections in the 0.62-1.80 GeV energy range yield \( a_\mu^{3\pi} = 48.91 \pm 0.23~(\mathrm{stat}) \pm 1.07~(\mathrm{syst}) \times 10^{-10} \) for the leading-order hadronic vacuum polarization contribution to the muon anomalous magnetic moment. This result differs by \(2.5\) standard deviations from the most precise current determination.
We report on a search for a heavy neutrino in the decays \(\tau^- \to \pi^- \nu_h\), \(\nu_h \to \pi^\pm \ell-+\), \(\ell = e, \mu\). The results are obtained using the full data sample collected ...with the Belle detector at the KEKB asymmetric energy \(e^+e^-\) collider. We observe no significant signal and set 90% CL upper limits on the couplings of the heavy right-handed neutrinos to the conventional SM left-handed neutrinos in the mass range 0.2-1.6 GeV/c\(^2\).
We report new measurements of the production cross sections of pairs of charged pions and kaons as a function of their fractional energies using various fractional-energy definitions. Two different ...fractional-energy definitions were used and compared to the conventional fractional-energy definition reported previously. The new variables aim at either identifying dihadron cross sections in terms of single-hadron fragmentation functions, or to provide a means of characterizing the transverse momentum created in the fragmentation process. The results were obtained applying the updated initial-state radiation correction used in other recent Belle publications on light-hadron production cross sections. In addition, production cross sections of single charged pions, kaons, and protons were also updated using this initial-state radiation correction. The cross sections are obtained from a \(558\,{\rm fb}^{-1}\) data sample collected at the \(\Upsilon(4S)\) resonance with the Belle detector at the KEKB asymmetric-energy \(e^+ e^-\) collider.
We measure the lifetime of the \(D_s^+\) meson using a data sample of 207 fb\(^{-1}\) collected by the Belle II experiment running at the SuperKEKB asymmetric-energy \(e^+ e^-\) collider. The ...lifetime is determined by fitting the decay-time distribution of a sample of \(116\times 10^3\) \(D_s^+\rightarrow\phi\pi^+\) decays. Our result is \(\tau^{}_{D^+_s} = (499.5\pm 1.7\pm 0.9)\) fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.
We search for \(CP\) violation by measuring a \(T\)-odd asymmetry in the Cabibbo-suppressed \(D^{+}\rightarrow K^{+}K^{0}_{S}\pi^{+}\pi^{-} \) decay, and in the Cabibbo-favored \(D^{+}_{s}\rightarrow ...K^{+}K^{0}_{S}\pi^{+}\pi^{-}\) and \(D^{+}\rightarrow K^{+}K^{-}K^{0}_{S}\pi^{+}\) decays. We use 980 \({\rm fb}^{-1}\) of data collected by the Belle detector running at the KEKB asymmetric-energy \(e^{+}e^{-}\) collider. The \(C\!P\)-violating \(T\)-odd parameter \({a}^{T\text{-}\rm{odd}}_{CP}\) is measured to be \({a}^{T\text{-}\rm{odd}}_{CP}(D^{+}\rightarrow K^{+}K^{0}_{S}\pi^{+}\pi^{-})=(0.34\pm0.87\pm0.32)\%,\) \({a}^{T\text{-}\rm{odd}}_{CP}(D^{+}_{s}\rightarrow K^{+}K^{0}_{S}\pi^{+}\pi^{-})=(-0.46\pm0.63\pm0.38)\%,\) and \({a}^{T\text{-}\rm{odd}}_{CP}(D^{+}\rightarrow K^{+}K^{-}K^{0}_{S}\pi^{+})=(-3.34\pm2.66\pm0.35)\%,\) where the first uncertainty is statistical and the second is systematic. We also report the first observation of the Cabibbo-suppressed decay \(D^{+}_{s}\rightarrow K^{+}K^{-}K^{0}_{S}\pi^{+}\). The branching fraction is measured relative to that of the analogous Cabibbo-favored decay : \(B(D^{+}_{s}\rightarrow K^{+}K^{-}K^{0}_{S}\pi^{+}) / B(D^{+}_{s}\rightarrow K^{+}K^{0}_{S}\pi^{+}\pi^{-}) = (1.36\pm 0.15\pm 0.04)\%\).
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