We report on patterning of miniaturized gold (Au) based micro-hotplates reaching high temperature at lower power consumption than ever reported using aerosol jet printing. Efficient heating (i.e. ...~12 °C/mW) was achieved by reducing the effective heating area and the thickness of the polyimide substrate. Au nanoparticles solution was used for printing heaters of two different sizes, i.e. 500 × 500 μm2 and 150 × 150 μm2. These double meander heaters were patterned on a 50 μm-thick polyimide substrate implementing 5 μm-thick membranes using laser etching. Finite element simulations were used to optimize the thermal design of the devices. They exhibit a power consumption at 250 °C of 39 mW and 22 mW for the larger and smaller heater design, respectively. These results indorse the significance of aerosol jet printing process at high resolution to realize high temperature and power efficient micro-hotplates on foil for applications such as; in portable gas and chemical sensors, thermal metrology and mapping, localized heating, thermal actuators and microfluidics etc.
A theoretical description of the convection-diffusion process in a homogeneous system enabling estimation of diffusion coefficients employing commercially available Y-junction microchannel is ...presented. A detailed numerical analysis based on finite volumes and finite differences, namely the explicit, implicit and Crank-Nicolson method, was performed and analyzed on the same domain in order to verify the proposed models. All numerical approaches provided stable solutions with certain numerical variations depending on the number of iterations defined by the mesh density. In addition, the method was validated with measurements of diffusion coefficients of some selected components in the short Y-junction microchannel. Benefits and possible pitfalls of this estimation method are discussed. Key words: diffusion coefficient, microfluidic device, Y-junction microchannel, mathematical model, numerical methods
The mechanisms by which carbon nanotubes nucleate and grow are still poorly understood. Understanding and mathematically describing the process is crucial for its optimization. This paper reviews ...different models which have been proposed to explain carbon nanotube growth in the chemical vapor deposition process. The review is divided into two sections, the first section describes some nucleation, growth and termination simulations based on molecular dynamics, and the second section describes some mathematical models based on transport and kinetics theories. Key words: Carbon nanotubes, CVD, growth simulations, kinetics
Global decay chain vertex fitting at Belle II Krohn, J.-F.; Tenchini, F.; Urquijo, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2020, Volume:
976, Issue:
C
Journal Article
Peer reviewed
Open access
In this paper we report the implementation of a global vertex fitting algorithm within the Belle II analysis software environment, which was originally developed for BaBar (Hulsbergen, 2005). We ...explore the impact of global vertex fitting algorithms for flavour physics analyses with the Belle II detector at the SuperKEKB e+e− collider, such as in the reconstruction of final states with neutral particles, and in fits with geometrical constraints from SuperKEKB’s nano-beam interaction region. The algorithm is compared to the standard vertex fitting algorithm employed by the Belle experiment. We have developed the fitting framework to utilise the EIGEN library for linear algebra operations, reducing the computation time for vertex fitting operations by an order of magnitude over previous methods. This has a significant impact on physics analysis computing efficiency, where vertex fitting over large combinations of final state particles is one of the most CPU intensive operations at Belle II.
The Full Event Interpretation Keck, T.; Abudinén, F.; Bernlochner, Florian U. ...
Computing and software for big science,
12/2019, Volume:
3, Issue:
1
Journal Article
Open access
The full event interpretation is presented: a new exclusive tagging algorithm used by the high-energy physics experiment Belle II. The experimental setup of Belle II allows the precise measurement of ...otherwise inaccessible
B
meson decay modes. The Full Event Interpretation algorithm enables many of these measurements. The algorithm relies on machine learning to automatically identify plausible
B
meson decay chains based on the data recorded by the detector. Compared to similar algorithms employed by previous experiments, the Full Event Interpretation provides a greater efficiency, yielding a larger effective sample size usable in the measurement.
We present the first measurements of absolute branching fractions of Ξc0 decays into Ξ−π+, ΛK−π+, and pK−K−π+ final states. The measurements are made using a dataset comprising (772±11)×106 BB¯ pairs ...collected at the ϒ(4S) resonance with the Belle detector at the KEKB e+e− collider. We first measure the absolute branching fraction for B−→Λ¯c−Ξc0 using a missing-mass technique; the result is B(B−→Λ¯c−Ξc0)=(9.51±2.10±0.88)×10−4. We subsequently measure the product branching fractions B(B−→Λ¯c−Ξc0)B(Ξc0→Ξ−π+), B(B−→Λ¯c−Ξc0)B(Ξc0→ΛK−π+), and B(B−→Λ¯c−Ξc0)B(Ξc0→pK−K−π+) with improved precision. Dividing these product branching fractions by the result for B−→Λ¯c−Ξc0 yields the following branching fractions: B(Ξc0→Ξ−π+)=(1.80±0.50±0.14)%, B(Ξc0→ΛK−π+)=(1.17±0.37±0.09)%, and B(Ξc0→pK−K−π+)=(0.58±0.23±0.05)%. For the above branching fractions, the first uncertainties are statistical and the second are systematic. Our result for B(Ξc0→Ξ−π+) can be combined with Ξc0 branching fractions measured relative to Ξc0→Ξ−π+ to yield other absolute Ξc0 branching fractions.
Using a data sample of 980 fb−1 of e+e− annihilation data taken with the Belle detector operating at the KEKB asymmetric-energy e+e− collider, we report the results of a study of excited Ξc states ...that decay, via the emission of photons and/or charged pions, into Ξc0 or Ξc+ ground state charmed-strange baryons. We present new measurements of the masses of all members of the Ξc′, Ξc(2645), Ξc(2790), Ξc(2815), and Ξc(2980) isodoublets, measurements of the intrinsic widths of those that decay strongly, and evidence of previously unknown transitions.
We have searched for the Cabibbo-suppressed decay Λc+→ϕpπ0 in e+e− collisions using a data sample corresponding to an integrated luminosity of 915 fb−1. The data were collected by the Belle ...experiment at the KEKB e+e− asymmetric-energy collider running at or near the ϒ(4S) and ϒ(5S) resonances. No significant signal is observed, and we set an upper limit on the branching fraction of B(Λc+→ϕpπ0)<15.3×10−5 at 90% confidence level. The contribution of nonresonant Λc+→K+K−pπ0 decays is found to be consistent with zero, and the corresponding upper limit on its branching fraction is set to be B(Λc+→K+K−pπ0)NR<6.3×10−5 at 90% confidence level. We also search for an intermediate hidden-strangeness pentaquark decay Ps+→ϕp. We see no evidence for this intermediate decay and set an upper limit on the product branching fraction of B(Λc+→Ps+π0)×B(Ps+→ϕp)<8.3×10−5 at 90% confidence level. Finally, we measure the branching fraction for the Cabibbo-favored decay Λc+→K−π+pπ0; the result is B(Λc+→K−π+pπ0)=(4.42±0.05(stat)±0.12(syst)±0.16(norm))%, which is the most precise measurement to date.
Here, we report a measurement of time-dependent CP violation in B0 → K0Sπ0π0 decays using a data sample of 772 × 106 B¯B pairs collected by the Belle experiment running at the Υ(4S) resonance at the ...KEKB e+e– collider. This decay proceeds mainly via a b → sd¯d “penguin” amplitude. The results are sin2Φeff1 = 0.92+0.27–0.31 (stat.) ±0.11 (syst.) and A = 0.28 ± 0.21 (stat.) ±0.04 (syst.), which are the most precise measurements of CP violation in this decay mode to date. The value for the CP-violating parameter sin2Φeff1 is consistent with that obtained using decay modes proceeding via a b → c¯cs “tree” amplitude.
We report the measurement of γγ→ηc(1S),ηc(2S)→η′π+π− with η′ decays to γρ and ηπ+π− using 941 fb−1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e− collider. The ηc(1S) ...mass and width are measured to be M=2984.6±0.7 (stat)±2.2 (syst)±0.3 (model) MeV/c2 and Γ=30.8−2.2+2.3 (stat)±2.5 (syst)±1.4 (model) MeV, respectively. First observation of ηc(2S)→η′π+π− with a significance of 5.5σ including systematic error is obtained, and the ηc(2S) mass is measured to be M=3635.1±3.7 (stat)±2.9 (syst)±0.4 (model) MeV/c2. The products of the two-photon decay width and branching fraction (B) of decays to η′π+π− are determined to be ΓγγΓγγB=65.4±2.6 (stat)±7.8 (syst) eV for ηc(1S) and 5.6−1.1+1.2 (stat)±1.1 (syst) eV for ηc(2S). The cross sections for γγ→η′π+π− and η′f2(1270) are measured for the first time.
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