We study the process e+e−→π+π−ηγ, where the photon is radiated from the initial state. About 8000 fully reconstructed events of this process are selected from the BABAR data sample with an integrated ...luminosity of 469 fb−1. Using the π+π−η invariant mass spectrum, we measure the e+e−→π+π−η cross section in the e+e− center-of-mass energy range from 1.15 to 3.5 GeV. The cross section is well described by the Vector-Meson dominance model with four ρ-like states. We observe 49±9 events of the J/ψ decay to π+π−η and measure the product ΓJ/Ψ→e+e−BJ/Ψ→π+π−η=2.34±0.43stat±0.16syst eV.
The third edition of Flow Cytometry Guidelines provides the key aspects to consider when performing flow cytometry experiments and includes comprehensive sections describing phenotypes and functional ...assays of all major human and murine immune cell subsets. Notably, the Guidelines contain helpful tables highlighting phenotypes and key differences between human and murine cells. Another useful feature of this edition is the flow cytometry analysis of clinical samples with examples of flow cytometry applications in the context of autoimmune diseases, cancers as well as acute and chronic infectious diseases. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid. All sections are written and peer‐reviewed by leading flow cytometry experts and immunologists, making this edition an essential and state‐of‐the‐art handbook for basic and clinical researchers.
We present first evidence that the cosine of the CP-violating weak phase 2β is positive, and hence exclude trigonometric multifold solutions of the Cabibbo-Kobayashi-Maskawa (CKM) Unitarity Triangle ...using a time-dependent Dalitz plot analysis of B^{0}→D^{(*)}h^{0} with D→K_{S}^{0}π^{+}π^{-} decays, where h^{0}∈{π^{0},η,ω} denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BABAR and Belle experiments collected at the ϒ(4S) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×10^{6}BBover ¯ pairs recorded by the BABAR detector and (772±11)×10^{6}BBover ¯ pairs recorded by the Belle detector. The results of the measurement are sin2β=0.80±0.14(stat)±0.06(syst)±0.03(model) and cos2β=0.91±0.22(stat)±0.09(syst)±0.07(model). The result for the direct measurement of the angle β of the CKM Unitarity Triangle is β=22.5±4.4(stat)±1.2(syst)±0.6(model)°. The measurement assumes no direct CP violation in B^{0}→D^{(*)}h^{0} decays. The quoted model uncertainties are due to the composition of the D^{0}→K_{S}^{0}π^{+}π^{-} decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a high-statistics e^{+}e^{-}→ccover ¯ data sample. CP violation is observed in B^{0}→D^{(*)}h^{0} decays at the level of 5.1 standard deviations. The significance for cos2β>0 is 3.7 standard deviations. The trigonometric multifold solution π/2-β=(68.1±0.7)° is excluded at the level of 7.3 standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle.
Using the initial-state radiation method, the e + e − → KSKL cross section from 1.98 to 2.54 GeV is measured in a data sample of 469 fb −1 collected with the BABAR detector. The results are used in ...conjunction with previous BABAR results for the e + e − → K + K − , e + e − → π + π − , e + e − → π + π − η , and e + e − → ω π π cross sections to investigate the nature of the resonance structure recently observed by the BESIII experiment in the e + e − → K+K− cross section.
The new SuperKEKB collider will be an upgrade of the existing KEKB electron-positron asymmetric machine, with a target luminosity of 8×1035 cm−2s−1, about 40 times greater than the previous one. The ...accelerator upgrade is based on the novel low-emittance "nanobeams" scheme. The detector will also be upgraded to cope with the higher luminosity, pile-up and occupancy. We report on the development of the new pure CsI calorimeter for the forward region. An intensive R&D has been carried out to study the performance of pure CsI crystals with Large Area Avalanche Photodiodes readout (LAAPD). Results on the signal to noise ratio for different sensors and front end electronics configurations will be presented as well as the use of filters and wavelength shifters. Measurements with a source, simulating the background machine, have been performed and will also be presented.
We search for invisible decays of the Upsilon(1S) meson using a sample of 91.4 x 10(6) Upsilon(3S) mesons collected at the BABAR/PEP-II B factory. We select events containing the decay Upsilon(3S) ...--> pi(+)pi(-)Upsilon(1S) and search for evidence of an undetectable Upsilon(1S) decay recoiling against the dipion system. We set an upper limit on the branching fraction B(Upsilon(1S) --> invisible) < 3.0 x 10(-4) at the 90% confidence level.
The process e+e−→π+π−2π0γ is investigated by means of the initial-state radiation technique, where a photon is emitted from the incoming electron or positron. Using 454.3 fb−1 of data collected ...around a center-of-mass energy of s=10.58 GeV by the BABAR experiment at SLAC, approximately 150000 signal events are obtained. The corresponding nonradiative cross section is measured with a relative uncertainty of 3.6% in the energy region around 1.5 GeV, surpassing all existing measurements in precision. Using this new result, the channel’s contribution to the leading order hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon is calculated as (gμπ+π−2π0−2)/2=(17.9±0.1stat±0.6syst)×10−10 in the energy range 0.85 GeV<ECM<1.8 GeV. In the same energy range, the impact on the running of the fine-structure constant at the Z0-pole is determined as Δαπ+π−2π0(MZ2)=(4.44±0.02stat±0.14syst)×10−4. Furthermore, intermediate resonances are studied and especially the cross section of the process e+e−→ωπ0→π+π−2π0 is measured.
The Belle II Physics Book Kou, E; Bishara, F; Brod, J ...
Progress of theoretical and experimental physics,
02/2020, Letnik:
2020, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The Belle II Theory Interface Platform (B2TiP) was created as a physics prospects working group of the Belle II collaboration in June 2014. It offered a platform where theorists and experimentalists ...could work together to elucidate the potential impacts of the Belle II program, which includes a wide scope of physics topics: B physics, charm, τ, quarkonium physics, electroweak precision measurements, and dark sector searches.
The decay τ−→K−KSντ has been studied using 430×106 e+e−→τ+τ− events produced at a center-of-mass energy around 10.6 GeV at the PEP-II collider and studied with the BABAR detector. The mass spectrum ...of the K−KS system has been measured and the spectral function has been obtained. The measured branching fraction B(τ−→K−KSντ)=(0.739±0.011(stat)±0.020(syst))×10−3 is found to be in agreement with earlier measurements.
We use 429 fb$^{-1}$ of $e^+e^-$ collision data collected at the $\Upsilon(4S)$ resonance with the BABAR detector to measure the radiative transition rate of $b\rightarrow s\gamma$ with a sum of 38 ...exclusive final states. The inclusive branching fraction with a minimum photon energy of 1.9 GeV is found to be $\mathcal{B}(\bar B \rightarrow X_{s}\gamma)=(3.29\pm 0.19\pm 0.48)\times 10^{-4}$ where the first uncertainty is statistical and the second is systematic. We also measure the first and second moments of the photon energy spectrum and extract the best fit values for the heavy-quark parameters, $m_{b}$ and $\mu_{\pi}^{2}$, in the kinetic and shape function models.
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