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 $\tau^{}_{D^+_s} = (498.7\pm 1.7\,^{+1.1}_{-0.8})$ fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.
We report the first search for a non-standard-model resonance decaying into $\tau$ pairs in $e^{+}e^{-}\rightarrow \mu^{+}\mu^{-} \tau^+\tau^-$ events in the 3.6-10 GeV/$c^{2}$ mass range. We use a ...62.8 fb$^{-1}$ sample of $e^+e^-$ collisions collected at a center-of-mass energy of 10.58 GeV by the Belle II experiment at the SuperKEKB collider. The analysis probes three different models predicting a spin-1 particle coupling only to the heavier lepton families, a Higgs-like spin-0 particle that couples preferentially to charged leptons (leptophilic scalar), and an axion-like particle, respectively. We observe no evidence for a signal and set exclusion limits at 90% confidence level on the product of cross section and branching fraction into $\tau$ pairs, ranging from 0.7 fb to 24 fb, and on the couplings of these processes. We obtain world-leading constraints on the couplings for the leptophilic scalar model for masses above 6.5 GeV/$c^2$ and for the axion-like particle model over the entire mass range.
We study the processes $e^{+}e^{–} → ωχ_{bJ}$(1P) (J=0, 1, or 2) using samples at center-of-mass energies $\sqrt{s}$ = 10.701, 10.745, and 10.805 GeV, corresponding to 1.6, 9.8, and 4.7 fb–1 of ...integrated luminosity, respectively. These data were collected with the Belle II detector during special operations of the SuperKEKB collider above the Υ(4S) resonance. We report the first observation of $ωχ_{bJ}$(1P) signals at $\sqrt{s}$ = 10.745 GeV. By combining Belle II data with Belle results at $\sqrt{s}$ = 10.867 GeV, we find energy dependencies of the Born cross sections for $e^{+}e^{–} → ωχ_{b1,b2}$(1P) to be consistent with the shape of the Υ(10753) state. These data indicate that the internal structures of the Υ(10753) and Υ(10860) states may differ. Including data at $\sqrt{s}$ = 10.653 GeV, we also search for the bottomonium equivalent of the X(3872) state decaying into ωΥ(1S). No significant signal is observed for masses between 10.45 and 10.65 GeV/c2.
The $L_{\mu}-L_{\tau}$ extension of the standard model predicts the existence of a lepton-flavor-universality-violating $Z^{\prime}$ boson that couples only to the heavier lepton families. We search ...for such a $Z^\prime$ through its invisible decay in the process $e^+ e^- \to \mu^+ \mu^- Z^{\prime}$. We use a sample of electron-positron collisions at a center-of-mass energy of 10.58GeV collected by the Belle II experiment in 2019-2020, corresponding to an integrated luminosity of 79.7fb$^{-1}$. We find no excess over the expected standard-model background. We set 90$\%$-confidence-level upper limits on the cross section for this process as well as on the coupling of the model, which ranges from $3 \times 10^{-3}$ at low $Z^{\prime}$ masses to 1 at $Z^{\prime}$ masses of 8$GeV/c^{2}$.
We study the processes $e^+e^-\to\omega\chi_{bJ}(1P)$ ($J$ = 0, 1, or 2) using samples at center-of-mass energies $\sqrt{s}$ = 10.701, 10.745, and 10.805 GeV, corresponding to 1.6, 9.8, and 4.7 ...fb$^{-1}$ of integrated luminosity, respectively. These data were collected with the Belle II detector during special operations of the SuperKEKB collider above the $\Upsilon(4S)$ resonance. We report the first observation of $\omega\chi_{bJ}(1P)$ signals at $\sqrt{s}$ = 10.745 GeV. By combining Belle II data with Belle results at $\sqrt{s}$ = 10.867 GeV, we find energy dependencies of the Born cross sections for $e^+e^-\to \omega\chi_{b1,b2}(1P)$ to be consistent with the shape of the $\Upsilon(10753)$ state. These data indicate that the internal structures of the $\Upsilon(10753)$ and $\Upsilon(10860)$ states may differ. Including data at $\sqrt{s}$ = 10.653 GeV, we also search for the bottomonium equivalent of the $X(3872)$ state decaying into $\omega\Upsilon(1S)$. No significant signal is observed for masses between 10.45 and 10.65 GeV/$c^2$.
We present a measurement of the Cabibbo-Kobayashi-Maskawa unitarity triangle angle φ3 (also known as γ) using a model-independent Dalitz plot analysis of B+ → D($ {K}_S^0 $h+h–)h+, where D is either ...a Do or Do¯ meson and h is either a π or K. This is the first measurement that simultaneously uses Belle and Belle II data, combining samples corresponding to integrated luminosities of 711 fb–1 and 128 fb–1, respectively. All data were accumulated from energy-asymmetric e+e– collisions at a centre-of-mass energy corresponding to the mass of the Υ(4S) resonance. We measure φ3 = (78.4 ± 11.4 ± 0.5 ± 1.0)°, where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is from the uncertainties on external measurements of the D-decay strong-phase parameters.
Aims and objectives. To determine caregiver opinion on their intensive care unit’s policies with regard to visiting hours, how families are informed and participate in patient care.
Background. ...Benefits of improving family access to the intensive care unit, information delivery and participation of families in care have been suggested.
Design. Survey of caregivers working in French‐speaking intensive care units.
Methods. An e‐mail invitation to complete an online, closed‐ended questionnaire was issued to caregivers registered in the mailing list of the French society of intensive care.
Results. Caregivers (n = 731) working in 222 adult and 41 paediatric intensive care units completed the questionnaire. Unlike in paediatric intensive care units, 58% of adult intensive care unit had restricted visiting hours (<4 hour). However, 63% of respondents would recommend extended visiting periods. A 24‐hour policy existed in 7% of adult intensive care units; 10% of respondents from these intensive care units thought reducing visiting periods would be very useful or essential; 81% thought that a 24‐hour policy contributed to improved relations with families; and only 9% thought that it was a hindrance to care. Over 90% of caregivers thought that families should be informed of patient progress in a designated room in the presence of the patient’s nurse and that patient records should report family meetings. This policy was only implemented in half of the cases. Family participation in care procedures was strongly encouraged in only 0·5% of adult intensive care units.
Conclusions. Intensive care unit caregivers are in favour of longer visiting hours, increased use of designated rooms for, and nurse participation in, meetings with families. Although caregivers do not associate families with care procedures, they considered that their presence during most interventions should be authorised.
Relevance to clinical practice. Our results could help in implementing intensive care unit policies concerning visiting hours, how families are informed and participate in patient care.
Two independent, home-dwelling geriatric patients presented with apathy at a general practice in the Netherlands and were seen by an elderly care physician after (non-)medical interventions had ...failed. Both patients were treated with low-dose methylphenidate. During treatment, apathy symptoms decreased and the patients became more active. Apathy is a frequent symptom of several neuropsychiatric diseases, depression and somatic conditions. Its incidence varies from 1.3% in healthy elderly people to more than 50% in the elderly with depression or dementia. In this clinical lesson we present these two cases and discuss considerations for treatment of apathy with methylphenidate.
