Various methods for the non-destructive characterization of radioactive waste packages are applied in routine operation for identification and quantification of their radioactive inventory. As accuracy and precision play are an important role in the final documentation, an approach based on Bayesian statistics is presented for the evaluation of transmission data measured by digital radial radiography. The results of these data evaluations are probability density functions allowing to make predictions of the probability for a value a parameter can have. Furthermore a priori information can be easily considered in these evaluations. The applicability of the method is demonstrated by some elementary examples and shall act encouragingly for interested users for own investigations.

The principle of applying a Bayesian Method using Markov Chain Monte Carlo sampling for the evaluation of segmented gamma scanning data for waste packages containing gamma-emitting radioactive waste including additional a-priori information is described in general and its application is demonstrated on simulated and measured data.

We report on the reconstruction of various charmless $B$ decays from electron-positron collisions at the energy corresponding to the $\Upsilon(4S)$ resonance collected with the Belle II detector at the SuperKEKB collider. We use simulation to devise optimized event selections and apply them to the full data set collected in 2019, corresponding to 8.7\,fb$^{-1}$ of integrated luminosity. We fit the difference between half of the collision energy and the $B$ candidate energy (in the $\Upsilon(4S)$ frame) for events restricted to a signal-rich range in beam-energy-constrained mass to search for charmless signals. Signal yields of approximately 80, 15, 20, 30, 90, and 160 decays are reconstructed for the channels $B^0 \to K^+\pi^-$, $B^0 \to \pi^+\pi^-$, $B^+ \to K^0_S(\to \pi^+\pi^-)\pi^+$, $B^+ \to K^+\pi^0(\to \gamma\gamma)$, $B^+ \to K^+K^-K^+$, and $B^+ \to K^+\pi^-\pi^+$, respectively. Yields and background contaminations are compatible with those expected from simulation and comparable with those obtained by the Belle experiment. The results show a good understanding of the detector performance and offer a reliable basis to assess projections for future reach.

T. Bilka∗†d , F. Abudinénn, K. Ackermannn, P. Ahlburge, H. Aiharaac, M. Albalawin, O. Alonsoai, L. Andriceko, R. Ayadah, T. Azizu, V. Babuh, S. Bacherag, S. Bahinipatip, Y. Baim, E. Barberioa, Ti. Baroncellia, To. Baroncellia, A. K. Basithq, G. Batignaniv,w, A. Bauerb, P. K. Beheraq, V. Bertacchiv,w, S. Bettariniv,w, B. Bhuyanr, R. Blanco j, F. Bosiw, M. Boronatak, L. Bosisiox,y, A. Bozekag, F. Buchsteinerb, C. Camienh, A. Caldwelln, G. Cariaa, G. Casarosav,w, M. Ceccantiw, D. Červenkovd , V. Chekeliann, T. Czankab, N. Dashp, M. De Nucciov,w, B. Deschampse, A. Dieguezai, J. Dingfeldere, Z. Doležald , D. Esperanteak, P. Fischeri, F. Fortiv,w, M. Frasn, A. Freyg, M. Friedlb, J. Fusterak, M. Gabrieln, K. Gadowh, U. Gebauerg, L. Germice, T. Gessler f , D. Getzkow f , L. Gioin, A. Glazovh, B. Gobboy, P. Gomisak, J. A. M. Grimaldoac, K. Haraad , M. Heck j, T. Hempereke, M. Henselo, T. Higuchiz, M. Hoekk, C. Irmlerb, A. Ishikawaab, I. Jaegleal,H. B. Jeonae, C. Jooz, M. Kaletaag, J. Kandrad , N. Kambaraad , K. H. Kangae, P. Kapustaag, C. Kieslingn, B. Kisielewskiag, D. Kittlingern, D. Kloseo, P. Kodyšd , C. Koffmaneo, T. Kohrikiad , S. KoikeC,ad , I. Komarovy, I. Konorovm, S. Krivokucao, H. Krügere, T. Kuhrl, W. Kühn f , M. Kumars, R. Kumart , P. Kvasničkad , C. La Licatax,y, C. Lacastaak, K. Lalwanis, L. Lancerix,y, J. S. Lange f , K. Lautenbach f , J. Y. Leea f , S. C. Leeae, U. Leisn, P. Leitln, D. Levitm, Y. Lian, J. Libbyq, G. Liemanno, Z. Liuc, T. Lueckv,w, F. Lüttickee, L. Macharskih, P. Mamminiw, C. Mariñase, A. Martiniv,w, S. N. Mayekaru, S. Mccarneyn, G. B. Mohantyu, T. Moriiz, H. G. Mosern, D. Moyaa j, F. J. Muellerh, F. Müllern, D. Münchow f , K. R. Nakamuraad , H. Nakayamaad ,Z. Natkaniecag, C. Niebuhrh, J. Ninkovico, Y. Onukiac, W. Ostrowiczag, U. Packheiserh, A. Paladinoz, E. Paoloniv,w, H. Parkae, B. Paschene, S. Paulm, I. Peric j, F. Poblotzkih, K. Prasanthu, C. Prazh, A. Profetiw, A. Rabusovm, I. RashevskayaA,y, K. K. Raou, S. P. Reiter f , Resmi P. K.q, R. Richtero, M. Ritterl, M. Ritzerti, G. Rizzov,w, M. Rozanskaag, S. Rummell, D. Sahoou, J. G. Sancheza j, L. Santeljam, J. Sasakiac, N. Satoad , B. Scavinok, G. Schallero, M. Schneckeo, F. Schoppero, H. Schreeckg, S. Schultschikb, C. Schwandab, B. Schwenkerg, R. Sedlmeyern, C. Sfientik, F. Simonn, S. Skambraksn, Y. Solovievh, B. Spruckk, R. Steverh, U. Stolzenbergg, J. Stypulaag, J. Suzukiad , E. Tafelmayero, M. Takahashih, S. Tanakaad , H. Tanigawaac, G. N. Taylora, R. Thalmeierb, T. Tsuboyamaad , P. Urquijoa, I. Vilaa j, A. L. Virtoa j, L. Vitalex,y, S. Vogtn, M. Vosak, K. Wanac, C. Wangc, S. Watanukiab, M. WatanabeC,aa, I. J. Watsonac, J. Webba, N. Wermese, C. Wessele, J. Wiechczynskiag, P. Wieduwiltg, S. Williamsa, H. Windeln, H. Yeh, H. Yinb, L. Zaniv,w, J. Zhaoc

We measure the branching fractions for the decays B̅^0 → D^*+ e^-ν̅_e and B̅^0 → D^*+μ^-ν̅_μ using 8.70 ± 0.09  fb^-1 of data collected by the Belle II experiment at the SuperKEKB asymmetric-energy e^+ e^- collider. Candidate signal decays are reconstructed with the subsequent decays D^*+→ D^0 π^+ and D^0→ K^-π^+. We obtain the results B(B̅^0 → D^*+ e^-ν̅_e) = (4.55±0.14(stat)±0.35 (syst)) % and B(B̅^0 → D^*+μ^-ν̅_μ) = (4.84± 0.13(stat)±0.37(syst)) %, in agreement with the world averages. The measurements serve to validate the full chain of detector operation and calibration, data collection and processing, and production of physics results in the case of semileptonic B-meson decays.

A DEpleted P-channel Field Effect Transistor (DEPFET) based pixel detector was developed for the Belle II VerteX Detector (VXD). It is designed to achieve a good impact parameter resolution better than 15μm at the very high luminosity conditions of this experiment. In the first half of 2018 four final production modules have been deployed in the commissioning run of the detector and their performance is discussed.

We report the first measurement of the D^∗ - meson polarization in the decay B^0 → D^*-τ^+ν_τ using the full data sample of 772× 10^6 BB̅ pairs recorded with the Belle detector at the KEKB electron-positron collider. Our result, F_L^D^∗ = 0.60 ± 0.08 ( stat) ± 0.04 ( sys), where F_L^D^∗ denotes the D^∗- meson longitudinal polarization fraction, agrees within about 1.7 standard deviations of the standard model prediction.

We report the first measurement of the $D^{ast -}$ meson polarization in the decay $B^0 to D^{*-} tau^+nu_{tau}$ using the full data sample of 772$times 10^6$ $Bbar{B}$ pairs recorded with the Belle detector at the KEKB electron-positron collider. Our result, $F_L^{D^ast} = 0.60 pm 0.08 ({rm stat}) pm 0.04 ({rm sys})$, where $F_L^{D^ast}$ denotes the $D^{ast-}$ meson longitudinal polarization fraction, agrees within about $1.7$ standard deviations of the standard model prediction.

The construction of the new accelerator at the Super Flavor Factory in Tsukuba, Japan, has been finalized and the commissioning of its detector (Belle II) has started. This new e$^{+}$e$^{-}$ machine (SuperKEKB) will deliver an instantaneous luminosity of $8\times10^{35}\mathrm{~cm}^{-2}\mathrm{s}^{-1}$, which is 40 times higher than the world record set by KEKB. In order to be able to fully exploit the increased number of events and provide high precision measurements of the decay vertex of the B meson systems in such a harsh environment, the Belle II detector will include a new 6 layer silicon vertex detector. Close to the beam pipe, 2 pixel and 4 double-sided strip detector layers will be installed. During its first data taking period in 2018, the inner volume of the Belle II detector was only partially equipped with the final vertex detector technologies. The remaining volume was covered with dedicated radiation monitors, collectively called BEAST II, in order to investigate the particle and synchrotron radiation backgrounds near the interaction point. In this note, the milestones of the commissioning of the Belle II vertex detector and BEAST II are reviewed and the detector performance and selected background measurements will be presented.

The Belle II experiment will run with a reduced beam asymmetry and a factor of 40 higher instantaneous luminosity compared to the Belle experiment. To cope with this and to be able to perform high precision vertex measurements for charge conjugation parity violating processes, a pixel detector based on DEPFET technology will be installed in the center of Belle II. Its basic properties and the DAQ chain are presented in this article.

We present a measurement of $R_{K^{ast}}$, the ratio of the branching fractions ${cal B}(Bto K^ast mu^+ mu^-)$ and ${cal B}(Bto K^ast e^+ e^-)$, for both charged and neutral $B$ mesons. The ratio for charged $B$ mesons, $R_{K{^{ast +}}}$, is the first measurement ever performed. The analysis is based on a data sample of $711~mathrm{fb}^{-1}$, containing $772times 10^{6}$ $Bbar B$ events, recorded at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider.

The Belle II experiment comes with a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric e(+)e(-) collider with energies tuned to Y(4S) resonance root s = 10.588 GeV. The accelerator has successfully completed the first phase of commissioning in 2016 and the first electron-positron collisions in Belle II took place in April 2018. Belle II features a newly designed silicon vertex detector based on DEPFET pixel and double-sided strip layers. Currently, a subset of the vertex detector is installed (Phase 2 of the experiment). Installation of the full detector (Phase 3) will be completed by the end of 2018. This paper describes the Phase 2 arrangement of the Belle II silicon vertex detector, with focus on the interconnection of detectors and their integration with the software framework of Belle II. Alignment issues are discussed based on detector simulations and first acquired data.

B. Schwenker∗g, F. Abudinénn, K. Ackermannn, P. Ahlburge, H. Aiharaac, M. Albalawin, O. Alonsoai, L. Andriceko, R. Ayadah, T. Azizu, V. Babuh, S. Bacherag, S. Bahinipatip, Y. Baim, E. Barberioa, Ti. Baroncellia, To. Baroncellia, A. K. Basithq, G. Batignaniv,w, A. Bauerb, P. K. Beheraq, V. Bertacchiv,w, S. Bettariniv,w, B. Bhuyanr, T. Bilkad , R. Blanco j, F. Bosiw, M. Boronatak, L. Bosisiox,y, A. Bozekag, F. Buchsteinerb, C. Camienh, A. Caldwelln, G. Cariaa, G. Casarosav,w, M. Ceccantiw, D. Červenkovd , V. Chekeliann, T. Czankab, N. Dashp, M. De Nucciov,w, B. Deschampse, A. Dieguezai, J. Dingfeldere, Z. Doležald , D. Esperanteak, P. Fischeri, F. Fortiv,w, M. Frasn, A. Freyg, M. Friedlb, J. Fusterak, M. Gabrieln, K. Gadowh, U. Gebauerg, L. Germice, T. Gessler f , D. Getzkow f , L. Gioin, B. Gobboy, P. Gomisak, J. A. M. Grimaldoac, K. Haraad , M. Heck j, T. Hempereke, M. Henselo, T. Higuchiz, M. Hoekk, C. Irmlerb, A. Ishikawaab, I. Jaegleal,H. B. Jeonae, C. Jooz, M. Kaletaag, J. Kandrad , N. Kambaraad , K. H. Kangae, P. Kapustaag, C. Kieslingn, B. Kisielewskiag, D. Kittlingern, D. Kloseo, P. Kodyšd , C. Koffmaneo, T. Kohrikiad , S. KoikeC,ad , I. Komarovy, I. Konorovm, S. Krivokucao, H. Krügere, T. Kuhrl, W. Kühn f , M. Kumars, R. Kumart , P. Kvasničkad , C. La Licatax,y, C. Lacastaak, K. Lalwanis, L. Lancerix,y, J. S. Lange f , K. Lautenbach f , J. Y. Leea f , S. C. Leeae, U. Leisn, P. Leitln, D. Levitm, Y. Lian, J. Libbyq, G. Liemanno, Z. Liuc, T. Lueckv,w, F. Lüttickee, L. Macharskih, P. Mamminiw, C. Mariñase, A. Martiniv,w, S. N. Mayekaru, S. Mccarneyn, G. B. Mohantyu, T. Moriiz, H. G. Mosern, D. Moyaa j, F. J. Muellerh, F. Müllern, D. Münchow f , K. R. Nakamuraad , H. Nakayamaad ,Z. Natkaniecag, C. Niebuhrh, J. Ninkovico, Y. Onukiac, W. Ostrowiczag, U. Packheiserh, A. Paladinoz, E. Paoloniv,w, H. Parkae, B. Paschene, S. Paulm, I. Peric j, F. Poblotzkih, K. Prasanthu, A. Profetiw, A. Rabusovm, I. RashevskayaA,y, K. K. Raou, S. P. Reiter f , Resmi P. K.q, R. Richtero, M. Ritterl, M. Ritzerti, G. Rizzov,w, M. Rozanskaag, S. Rummell, D. Sahoou, J. G. Sancheza j, L. Santeljam, J. Sasakiac, N. Satoad , B. Scavinok, G. Schallero, M. Schneckeo, F. Schoppero, H. Schreeckg, S. Schultschikb, C. Schwandab, R. Sedlmeyern, C. Sfientik, F. Simonn, S. Skambraksn, Y. Solovievh, B. Spruckk, R. Steverh, U. Stolzenbergg, J. Stypulaag, J. Suzukiad , E. Tafelmayero, M. Takahashih, S. Tanakaad , H. Tanigawaac, G. N. Taylora, R. Thalmeierb, T. Tsuboyamaad , P. Urquijoa, I. Vilaa j, A. L. Virtoa j, L. Vitalex,y, S. Vogtn, M. Vosak, K. Wanac, C. Wangc, S. Watanukiab, M. WatanabeC,aa, I. J. Watsonac, J. Webba, N. Wermese, C. Wessele, J. Wiechczynskiag, P. Wieduwiltg, S. Williamsa, H. Windeln, H. Yeh, H. Yinb, L. Zaniv,w, J. Zhaoc

We report a search for charmless hadronic decays of charged B mesons to the final states K^0_S K^0_S K^± and K^0_S K^0_Sπ^± . The results are based on a 711 fb^-1 data sample that contains 772 × 10^6 B B̅ pairs, and was collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. For B^±→ K^0_S K^0_S K^± decays, the measured branching fraction and direct CP asymmetry are [10.64±0.49(stat)± 0.44(syst)]×10^-6 and [-0.6±3.9(stat)± 3.4(syst)] respectively. In the absence of a statistically significant signal for B^±→ K^0_S K^0_Sπ^±, we set the 90 upper limit on its branching fraction at 1.14 × 10^-6.

We present a new measurement of the CKM matrix element $|V_{cb}|$ from $ B^{0} rightarrow D^{*}ell nu$ decays, reconstructed with full Belle data set ($711 , rm fb^{-1}$). Two form factor parameterisations, based on work by the CLN and BGL groups, are used to extract the product $mathcal{F}(1)eta_{rm EW}|V_{cb}|$ and the decay form factors, where $mathcal{F}(1)$ is the factor normalisation and $eta_{rm EW}$ is a small electroweak correction. In the CLN parameterisation we find $mathcal{F}(1)eta_{rm EW}|V_{cb}| = (35.06 pm 0.15 pm 0.54) times 10^{-3}$, $rho^{2}=1.106 pm 0.031 pm 0.007$, $R_{1}(1)=1.229 pm 0.028 pm 0.009$, $R_{2}(1)=0.852 pm 0.021 pm 0.006$. In the BGL parameterisation we find $mathcal{F}(1)eta_{rm EW}|V_{cb}|= 38.73 pm 0.25 pm 0.60$, which is higher but consistent with the determination from inclusive semileptonic $B$ decays when correcting for $mathcal{F}(1)eta_{rm EW}$. This is the most precise measurement of $mathcal{F}(1)eta_{rm EW}|V_{cb}|$ and form factors that has ever been carried out, and the first direct study of the BGL form factor parameterisation in an experimental measurement.

The vertex detector used in the upgrade of High-Energy physics experiment Belle II includes DEPFET pixel detector (PXD) technology. In this complex topology the power supply units and the front-end electronics are connected through a PXD power cable bundle which may propagate the output noise from the power supplies to the vertex area. This paper presents a study of the propagation of noise caused by power converters in the PXD cable bundle based on Multi-conductor Transmission Line (MTL) theory. The work exposes the effect of the complex cable topology and shield connections on the noise propagation, which has an impact on the requirements of the power supplies. This analysis is part of the electromagnetic compatibility based design focused on functional safety to define the shield connections and power supply specifications required to ensure the successful integration of the detector and, specifically, to achieve the designed performance of the front-end electronics.

We report the first measurement of the D∗− meson polarization in the decay B0 → D∗−τ+ντ using the full data sample of 772×106 BB¯ pairs recorded with the Belle detector at the KEKB electron-positron collider. Our result, FLD∗ = 0.60 ±0.08(stat) ±0.04(sys), where FLD∗ denotes the D∗− meson longitudinal polarization fraction, agrees within about 1.7 standard deviations of the standard model prediction.

Abstract We present the first measurement of the Michel parameters η ‾ and ξκ in the radiative leptonic decay of the τ lepton using 703 fb-1 of data collected with the Belle detector at the KEKB e + e − collider. The Michel parameters are measured by an unbinned maximum likelihood fit to the kinematic information of e + e − → τ + τ − → ( π + π 0 ν ‾ ) ( l − ν ν ‾ γ ) ( l = e  or  μ ) . The preliminary values of the measured Michel parameters are η ‾ = − 2.0 ± 1.5 ± 0.8 and ξ κ = 0.6 ± 0.4 ± 0.2 , where the first error is statistical and the second is systematic.

We report the first measurement of the τ lepton polarization in the decay B̅→ D^* τ^- ν̅_τ as well as a new measurement of the ratio of the branching fractions R(D^*) = ℬ(B̅→ D^* τ^- ν̅_τ) / ℬ(B̅→ D^* ℓ^- ν̅_ℓ), where ℓ^- denotes an electron or a muon, with the decays τ^- →π^- ν_τ and τ^- →ρ^- ν_τ. We use the full data sample of 772 × 10^6 BB̅ pairs accumulated with the Belle detector at the KEKB electron-positron collider. Our preliminary results, R(D^*) = 0.276 ± 0.034 (stat.) ^+0.029 _-0.026 (syst.) and P_τ = -0.44 ± 0.47 (stat.) ^+0.20 _-0.17 (syst.), are consistent with the theoretical predictions of the Standard Model within 0.6 standard deviation.