219 research outputs found
Search for Axionlike Particles Produced in e+e- Collisions at Belle II
© 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article\u27s title, journal citation, and DOI. Funded by SCOAP3. We present a search for the direct production of a light pseudoscalar a decaying into two photons with the Belle II detector at the SuperKEKB collider. We search for the process e+e-→γa, a→γγ in the mass range 0.
Measurement of the integrated luminosity of the Phase 2 data of the Belle II experiment
© 2019 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd. From April to July 2018, a data sample at the peak energy of the γ(4S) resonance was collected with the Belle II detector at the SuperKEKB electron-positron collider. This is the first data sample of the Belle II experiment. Using Bhabha and digamma events, we measure the integrated luminosity of the data sample to be (496.3 ± 0.3 ± 3.0) pb-1, where the first uncertainty is statistical and the second is systematic. This work provides a basis for future luminosity measurements at Belle II
Sex differences in short-term mate preferences and behavioral mimicry: A semi-naturalistic experiment
Item does not contain fulltextStudies on short-term mating (STM) yield sex differences regarding preferences for attractiveness (important towomen, very important to men) and social status (very important to women, not to men) in potential mates. Additionally, men generally report a greater desire to engage in STM than women. So far, this evidence is primarily based on studies using vignettes or surveys. The current study extended the findings on sex differences in STM by examining actual behavior and STM-desires towards real people of the opposite sex. It investigated whether (1) sex differences exist in STM-desire, (2) whether this desire was affected by a confederate's attractiveness and status, and (3) if these sex differences were also reflected in interpersonal behavior (mimicry). In a pub-like laboratory, single heterosexual participants performed a task alongside a confederate of the
opposite sex, who differed in attractiveness and social status. Mimicry was observed and explicit STM-desire was assessed. Results showed that men only desired STM more than women in the case of an attractive partner. Women's STMdesire did not vary as a function of status or ttractiveness of the potential partner. Men’s, but not women's, mimicry paralleled these differential STM-desires. These results underline the conditionality of sex differences in STM-desire and provide a useful paradigm to further investigate STM.10 p
Measurements of the branching fractions for decays at Belle II
This paper reports a study of decays using
fb of data collected during 2019--2020 by the Belle II experiment at the
SuperKEKB asymmetric-energy collider, corresponding to events. We find , ,
, and signal events in the decay modes , ,
, and , respectively. The uncertainties quoted for the
signal yield are statistical only. We report the branching fractions of these
decays: where the first
uncertainty is statistical, and the second is systematic. The results are
consistent with world-average values
Precise Measurement of the D and D Lifetimes at Belle II
We report a measurement of the D and D lifetimes using D→Kπ and D→Kππ decays reconstructed in ee→ data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy ee collider. The data, collected at center-of-mass energies at or near the Υ(4S) resonance, correspond to an integrated luminosity of 72 fb. The results, τ(D)=410.5±1.1(stat)±0.8(syst) fs and τ(D)=1030.4±4.7(stat)±3.1(syst) fs, are the most precise to date and are consistent with previous determinations
Measurement of the integrated luminosity of the Phase 2 data of the Belle II experiment
From April to July 2018, a data sample at the peak energy of the γ(4S) resonance was collected with the Belle II detector at the SuperKEKB electron-positron collider. This is the first data sample of the Belle II experiment. Using Bhabha and digamma events, we measure the integrated luminosity of the data sample to be (496.3 ± 0.3 ± 3.0) pb-1, where the first uncertainty is statistical and the second is systematic. This work provides a basis for future luminosity measurements at Belle II
Angular analysis of decays reconstructed in 2019, 2020, and 2021 Belle II data
We report on a Belle II measurement of the branching fraction
(), longitudinal polarization fraction (), and CP asymmetry
() of decays. We reconstruct decays in a
sample of SuperKEKB electron-positron collisions collected by the Belle II
experiment in 2019, 2020, and 2021 at the (4S) resonance and
corresponding to 190 fb of integrated luminosity. We fit the
distributions of the difference between expected and observed candidate
energy, continuum-suppression discriminant, dipion masses, and decay angles of
the selected samples, to determine a signal yield of events. The
signal yields are corrected for efficiencies determined from simulation and
control data samples to obtain $\mathcal{B}(B^+ \to \rho^+\rho^0) = [23.2^{+\
2.2}_{-\ 2.1} (\rm stat) \pm 2.7 (\rm syst)]\times 10^{-6}f_L = 0.943 ^{+\
0.035}_{-\ 0.033} (\rm stat)\pm 0.027(\rm syst)\mathcal{A}_{CP}=-0.069
\pm 0.068(\rm stat) \pm 0.060 (\rm syst)\mathcal{A}_{CP}B^+\to
\rho^+\rho^0$ decays reported by Belle II
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