1,193 research outputs found
LAPPD operation using ToFPETv2 PETSYS ASIC
Single photon sensitive detectors used in high energy physics are, in some
applications, required to cover very large areas, and more specifically in very
strong demand with an ever finer imaging and timing capability for Cherenkov
Ring Imaging Detector (RICH) configurations. We are evaluating the Large Area
Picosecond Photo-detector (LAPPD) produced by INCOM company, as a possible
candidate for future RICH detector upgrades. In this work we perform tests on
the first generation device, which is capacitively coupled to a custom designed
anode back plane, consisting of various pixels and strips varying in size, that
allows for connecting various readout systems such as standard laboratory
equipment, as well as the TOFPET2 ASIC from PETsys company [2]. Our aim is to
evaluate what can be achieved by merging currently available technology, in
order to find directions for future developments adapted for specific uses.Comment: Twepp 2022 workshop proceeding
B-flavor tagging at Belle II
We report on new flavor tagging algorithms developed to determine the quark-flavor content of bottom ([InlineMediaObject not available: see fulltext.]) mesons at Belle II. The algorithms provide essential inputs for measurements of quark-flavor mixing and charge-parity violation. We validate and evaluate the performance of the algorithms using hadronic [InlineMediaObject not available: see fulltext.] decays with flavor-specific final states reconstructed in a data set corresponding to an integrated luminosity of 62.8 fb- 1, collected at the [InlineEquation not available: see fulltext.] resonance with the Belle II detector at the SuperKEKB collider. We measure the total effective tagging efficiency to be εeff=(30.0±1.2(stat)±0.4(syst))%for a category-based algorithm and εeff=(28.8±1.2(stat)±0.4(syst))%for a deep-learning-based algorithm
Search for lepton-flavor-violating tau-lepton decays to ℓγ at Belle
Charged lepton flavor violation is forbidden in the Standard Model but possible in several new physics scenarios. In many of these models, the radiative decays τ± → ℓ±γ (ℓ = e, μ) are predicted to have a sizeable probability, making them particularly interesting channels to search at various experiments. An updated search via τ± → ℓ±γ using full data of the Belle experiment, corresponding to an integrated luminosity of 988 fb−1, is reported for charged lepton flavor violation. No significant excess over background predictions from the Standard Model is observed, and the upper limits on the branching fractions, B(τ± → μ±γ) ≤ 4.2 × 10−8 and B(τ± → e±γ) ≤ 5.6 × 10−8, are set at 90% confidence level. [Figure not available: see fulltext.]
Measurement of the branching fraction of the decay B+ →π+π-ℓ+νℓ in fully reconstructed events at Belle
We present an analysis of the exclusive B+→π+π-ℓ+νℓ decay, where ℓ represents an electron or a muon, with the assumption of charge-conjugation symmetry and lepton universality. The study exploits the full ϒ(4S) data sample collected by the Belle detector, corresponding to 711 fb-1 of integrated luminosity. Events are selected by fully reconstructing one B meson in hadronic decay modes, subsequently determining the properties of the other B meson. We extract the signal yields using a binned maximum-likelihood fit to the missing-mass squared distribution in bins of the invariant mass of the two pions or the momentum transfer squared. We measure a total branching fraction of B(B+→π+π-ℓ+νℓ)=[22.7-1.6+1.9(stat)±3.5(syst)]×10-5, where the uncertainties are statistical and systematic, respectively. This result is the first reported measurement of this decay
Full density calcium phosphate bioceramics from nanopowders by sintering
Poster presented at the Adriatic School of Nanoscience – ASON-1, Dubrovnik, Croatia, September 19–23, 201
Search for CP violation in the decays and
We have searched for CP violation in the charmed meson decays and using 673 fb of data
collected with the Belle detector at the KEKB asymmetric-energy
collider. No evidence for CP violation is observed. We report the most
sensitive CP asymmetry measurements to date for these decays: , , , and , where the first uncertainties are statistical and
the second are systematic
Search for CP Violation in the Decays
We have searched for CP violation in the decays
where denotes a neutral pseudo-scalar meson which is either a ,
, or using KEKB asymmetric-energy collision data
corresponding to an integrated luminosity of 791 fb collected with the
Belle detector. No evidence of significant CP violation is observed. We report
the most precise CP asymmetry measurement in the decay to date: . We also report the first measurements of
CP asymmetries in the decays and : and , respectively
Evidence of the Purely Leptonic Decay B- --> tau- nu_tau-bar
We present the first evidence of the decay B- --> tau- nu_tau-bar using 414
fb^-1 of data collected at the Upsilon(4S) resonance with the Belle detector at
the KEKB asymmetric-energy e+e- collider. Events are tagged by fully
reconstructing one of the B mesons in hadronic modes. We detect the signal with
a significance of 3.5 standard deviations including systematics, and measure
the branching fraction to be Br(B- --> tau- nu_tau-bar) = (1.79
+0.56-0.49(stat) +0.46-0.51(syst))*10^-4. This implies that f_B = 0.229
+0.036-0.031(stat) +0.034-0.037(syst) GeV and is the first direct measurement
of this quantity.Comment: 6 pages, 3 figures, to appear in Physical Review Letter
Measurements of Branching Fractions and Time-dependent CP Violating Asymmetries in Decays
We report measurements of branching fractions and time-dependent CP
asymmetries in and decays
using a data sample that contains pairs
collected at the resonance with the Belle detector at the KEKB
asymmetric-energy collider. We determine the branching fractions to
be
and . We measure CP asymmetry parameters and in and , ,
, and in , where the first uncertainty is
statistical and the second is systematic. We exclude the conservation of CP
symmetry in both decays at equal to or greater than significance.Comment: 7 pages, 2 figure
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