Plasmid vectors have been widely used for DNA vaccines and gene therapy. Following intramuscular injection, the plasmid that persists is extrachromosomal and integration into host DNA, if it occurs ...at all, is negligible. However, new technologies for improving DNA delivery could increase the frequency of integration. In the present study, we tested the effect of electroporation on plasmid uptake and potential integration following intramuscular injection in mice, using a plasmid containing the mouse erythropoietin gene. Electroporation increased plasmid tissue levels by approximately six- to 34-fold. Using a quantitative gel-purification assay for integration, electroporation was found to markedly increase the level of plasmid associated with high-molecular-weight genomic DNA. To confirm integration and identify the insertion sites, we developed a new assay - referred to as repeat-anchored integration capture (RAIC) PCR - that is capable of detecting rare integration events in a complex mixture in vivo. Using this assay, we identified four independent integration events. Sequencing of the insertion sites suggested a random integration process, but with short segments of homology between the vector breakpoint and the insertion site in three of the four cases. This is the first definitive demonstration of integration of plasmid DNA into genomic DNA following injection in vivo.
A search for the flavor-changing neutral-current decay B+ →K+$ν\bar{ν}$ is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data sample ...corresponds to an integrated luminosity of 63 fb-1 collected at the Υ (4S) resonance and a sample of 9 fb-1 collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B+ →K+$ν\bar{ν}$ decay, but also the inclusive properties of the other B meson in the Υ(4S) $B\bar{B}$ event, to suppress the background from other B meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of B+ →K+$ν\bar{ν}$ of 4.1 × 10-5 is set at the 90% confidence level.
The novel MPGD-based photon detectors of COMPASS RICH-1 consist of large-size hybrid MPGDs with multi-layer architecture including two layers of Thick-GEMs and a bulk resistive MicroMegas. The top ...surface of the first THGEM is coated with a CsI film which also acts as photo-cathode. These detectors have been successfully in operation at COMPASS since 2016. Concerning bias-voltage supply, the Thick-GEMs are segmented in order to reduce the energy released in case of occasional discharges, while the MicroMegas anode is segmented into pads individually biased with positive voltage while the micromesh is grounded. In total, there are about ten different electrode types and more than 20000 electrodes supplied by more than 100 HV channels, where appropriate correlations among the applied voltages are required for the correct operation of the detectors. Therefore, a robust control system is mandatory, implemented by a custom designed software package, while commercial power supply units are used. This sophisticated control system allows to protect the detectors against errors by the operator, to monitor and log voltages and currents at 1 Hz rate, and automatically react to detector misbehavior. In addition, a voltage compensation system has been developed to automatically adjust the biasing voltage according to environmental pressure and temperature variations, to achieve constant gain over time. This development answers to a more general need. In fact, voltage compensation is always a requirement for the stability of gaseous detectors and its need is enhanced in multi-layer ones.
In this paper, the HV system and its performance are described in details, as well as the stability of the novel MPGD-based photon detectors during the physics data taking at COMPASS.
We present measurements of the first to fourth moments of the lepton mass squared $q$2 of $B$ → $X_cℓ\overline{ν}_ℓ$ decays for $ℓ = e, μ$ and with $X_c$ a hadronic system containing a charm quark. ...These results use a sample of electron-positron collisions at the $Υ$($4S$) resonance corresponding to 62.8 fb-1 of integrated luminosity and collected by the Belle II 2 experiment in 2019 and 2020. To identify the $X_c$ system and reconstruct $q$2, one of the $B$ mesons from an $Υ$($4S$) → $B\overline{B}$ decay is fully reconstructed in a hadronic decay mode using a multivariate $B$ tagging algorithm. We report raw and central moments for $q$2 > 1.5 $GeV$2=$c$4 up to $q$2 > 8.5 $GeV$2=$c$4, probing up to 77% of the accessible $B$ → $X_cℓ\overline{ν}_ℓ$ phase space. This is the first measurement of moments in the experimentally challenging range of 1.5; 2.5 $GeV$2=$c$4. The results can be used for a new determination of |$V_{cb}$| using inclusive $B$ → $X_cℓ\overline{ν}_ℓ$ decays.
Abstract We present a measurement of the Cabibbo-Kobayashi-Maskawa unitarity triangle angle ϕ 3 (also known as γ) using a model-independent Dalitz plot analysis of B + → D ( K S 0 $$ {K}_S^0 $$ h + h ...− )h +, where D is either a D 0 or D ¯ $$ \overline{D} $$ 0 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 ϕ 3 = (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.
We propose a new algorithm for the identification of the production flavor of neutral D mesons in the Belle II experiment. The algorithm exploits the correlation between the flavor of a reconstructed ...neutral D meson (signal D meson) and the electric charges of particles reconstructed in the rest of the e+e–→$c\bar{c}$ event. These include those originating from the decay of the other charm hadron produced in the event, as well as those possibly produced in association with the signal D meson. We develop the algorithm using simulation and calibrate it in data using decay modes that identify the flavor of the decaying neutral D meson. We use a data sample of e+e– collisions, corresponding to 362 fb–1 of integrated luminosity, collected by Belle II at center-of-mass energies near the Υ(4S) mass. The effective tagging efficiency in data is (47.91±0.07 (stat) ±0.51 (syst)) %, independent of the neutral-D-meson decay mode. This charm flavor tagger will approximately double the effective sample size of many CP-violation and charm-mixing measurements that so far have exclusively relied on neutral D mesons originating from D*± decays. While developed for Belle II, the basic principles underlying the charm flavor tagger can be used in other experiments, including those at hadron colliders.
We report a measurement of decay-time-dependent charge-parity ( C P ) asymmetries in B 0 → K S 0 K S 0 K S 0 decays. We use 387 × 10 6 B B ¯ pairs collected at the ϒ ( 4 S ) resonance with the Belle ...II detector at the SuperKEKB asymmetric-energy electron-positron collider. We reconstruct 220 signal events and extract the C P -violating parameters S and C from a fit to the distribution of the decay-time difference between the two B mesons. The resulting confidence region is consistent with previous measurements in B 0 → K S 0 K S 0 K S 0 and B 0 → ( c c ¯ ) K 0 decays and with predictions based on the standard model. Published by the American Physical Society 2024
Evidence for B + → K + ν ν ¯ decays Adachi, I.; Aggarwal, L.; Aloisio, A. ...
Physical review. D,
6/2024, Letnik:
109, Številka:
11
Journal Article
Recenzirano
We search for the rare decay B + → K + ν ν ¯ in a 362 fb − 1 sample of electron-positron collisions at the ϒ ( 4 S ) resonance collected with the Belle II detector at the SuperKEKB collider. We use ...the inclusive properties of the accompanying B meson in ϒ ( 4 S ) → B B ¯ events to suppress background from other decays of the signal B candidate and light-quark pair production. We validate the measurement with an auxiliary analysis based on a conventional hadronic reconstruction of the accompanying B meson. For background suppression, we exploit distinct signal features using machine learning methods tuned with simulated data. The signal-reconstruction efficiency and background suppression are validated through various control channels. The branching fraction is extracted in a maximum likelihood fit. Our inclusive and hadronic analyses yield consistent results for the B + → K + ν ν ¯ branching fraction of 2.7 ± 0.5 ( stat ) ± 0.5 ( syst ) × 10 − 5 and 1.1 − 0.8 + 0.9 ( stat ) − 0.5 + 0.8 ( syst ) × 10 − 5 , respectively. Combining the results, we determine the branching fraction of the decay B + → K + ν ν ¯ to be 2.3 ± 0.5 ( stat ) − 0.4 + 0.5 ( syst ) × 10 − 5 , providing the first evidence for this decay at 3.5 standard deviations. The combined result is 2.7 standard deviations above the standard model expectation. Published by the American Physical Society 2024
A
bstract
We present a measurement of the Cabibbo-Kobayashi-Maskawa unitarity triangle angle
ϕ
3
(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
D
0
or
D
¯
0
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(4
S
) resonance. We measure
ϕ
3
= (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.
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