First Observation of the Hadronic Transition Υ(4S)→ηhb(1P) and New Measurement of the hb(1P) and ηb(1S) Parameters

Using a sample of 771.6×106 ΥΥ(4S) decays collected by the Belle experiment at the KEKB e+e− collider, we observe, for the first time, the transition Υ(4S)→ηhb(1P) with the branching fraction B[Υ(4S)→ηhb(1P)]=(2.18±0.11±0.18)×10−3 and we measure the hb(1P) mass Mhb(1P)=(9899.3±0.4±1.0)  MeV/c2, corresponding to the hyperfine (HF) splitting ΔMHF(1P)=(0.6±0.4±1.0)  MeV/c2. Using the transition hb(1P)→γηb(1S), we measure the ηb(1S) mass Mηb(1S)=(9400.7±1.7±1.6)  MeV/c2, corresponding to ΔMHF(1S)=(59.6±1.7±1.6)  MeV/c2, the ηb(1S) width Γηb(1S)=(8+6−5±5)  MeV/c2 and the branching fraction B[hb(1P)→γηb(1S)]=(56±8±4)%

Inclusive study of bottomonium production in association with an η meson in e+e− annihilations near Υ(5S)

We study bottomonium production in association with an η meson in e+e− annihilations near the Υ(5S), at a center of mass energy of s√=10.866GeV. The results are based on the 121.4fb−1 data sample collected by the Belle experiment at the asymmetric energy KEKB collider. Only the η meson is reconstructed and the missing-mass spectrum of η candidates is investigated. We observe the e+e−→ηΥJ(1D) process and find evidence for the e+e−→ηΥ(2S) process, while no significant signals of Υ(1S), hb(1P), nor hb(2P) are found. Cross sections for the studied processes are reported

First Observation of the Hadronic Transition Υ(4S)→ηhb(1P)and New Measurement of the hb(1P) and ηb(1S) Parameters

Using a sample of 771.6×106 ΥΥ(4S) decays collected by the Belle experiment at the KEKB e+e− collider, we observe, for the first time, the transition Υ(4S)→ηhb(1P) with the branching fraction B[Υ(4S)→ηhb(1P)]=(2.18±0.11±0.18)×10−3 and we measure the hb(1P) mass Mhb(1P)=(9899.3±0.4±1.0)  MeV/c2, corresponding to the hyperfine (HF) splitting ΔMHF(1P)=(0.6±0.4±1.0)  MeV/c2. Using the transition hb(1P)→γηb(1S), we measure the ηb(1S) mass Mηb(1S)=(9400.7±1.7±1.6)  MeV/c2, corresponding to ΔMHF(1S)=(59.6±1.7±1.6)  MeV/c2, the ηb(1S) width Γηb(1S)=(8+6−5±5)  MeV/c2and the branching fraction B[hb(1P)→γηb(1S)]=(56±8±4)%

The Full Event Interpretation -- An exclusive tagging algorithm for the Belle II experiment

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.Comment: 11 pages, 7 figures, 1 tabl

Cystic echinococcosis in wild boars (Sus scrofa) from southern Italy: Epidemiological survey and molecular characterization.

Cystic Echinococcosis (CE) caused by Echinococcus granulosus sensu lato (s.l.) is one of the most important parasitic zoonotic diseases in the world and it represents an important public health and socio-economic concern. In the Mediterranean basin, CE is widespread and it is endemic in Italy, with major prevalence in southern areas. Several studies have investigated CE in domestic pigs, however, such data in wild boars are scant. In the last decades the wild boar population in Italy has increased and this ungulate could play an important role in the spreading ofCEinthewild.Here wereporton theprevalenceandfertility rateofhydatid cystsinwildboarsthat were shot during two hunting seasons (2016–2017) in the Campania region of southern Italy. For each animal, a detailed inspection of the carcass and organs (lungs, liver and spleen) was performed and when cysts were found, their number, morphology and fertility were determined by visual and microscopic examination. Cysts were classified morphologically as fertile, sterile, caseous and calcified. Protoscoleces and germinal layers were collected from individual cysts and DNA was extracted to identify different strains/genotypes of E. granulosus s.l. Outofatotalof2108wildboars93(4.4%)werefoundpositiveforCE.Infectedanimalswere45malesand48 females, aged between 1 and 8 years. The average number of cysts per wild boar was 1.3 (min 1 - max 13). The total number of cysts collected was 123, of which 118 (95.9%) in the liver, 4 (3.3%) in the lungs and 1 (0.8%) in the spleen. Of all analyzed cysts, 70 (56.9%) were fertile and 53 (43.1%) sterile/acephalous. The presence of fertile cysts in 19.4% of CE-positive animals is noteworthy. Overall, molecular diagnosis showed 19 wild boars infected with the pig strain (G7)

Global Decay Chain Vertex Fitting at B-Factories

We present a particle vertex fitting method designed for B factories. The presented method uses a Kalman Filter to solve a least squares estimate to globally fit decay chains, as opposed to traditional methods that fit each vertex at a time. It allows for the extraction of particle momenta, energies, vertex positions and flight lengths, as well as the uncertainty estimates of these quantities. Furthermore, it allows for the precise extraction of vertex parameters in complex decay chains containing neutral final state particles, such as ${\gamma}$ or $K^0_L$ , which cannot properly be tracked due to limited spatial resolution of longitudinally segmented single-layer crystal calorimeters like the Belle II ECL. The presented technique can be used to suppress combinatorial background and improve resolutions on measured parameters. We present studies using Monte Carlo simulations of collisions in the Belle II experiment, where modes with neutrals are crucial to the physics analysis program

Search for the decay B+→K‾∗0K∗+B^+\rightarrow\overline{K}{}^{*0}K^{*+} at Belle

We report a search for the rare charmless decay $B^+\rightarrow\overline{K}{}^{*0}K^{*+}$ using a data sample of $772\times10^6$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. No statistically significant signal is found and a 90% confidence-level upper limit is set on the decay branching fraction as $\mathcal{B}(B^+\rightarrow\overline{K}{}^{*0}K^{*+}) <1.31\times 10^{-6}$.Comment: 8 pages, 3 figures, submitted to PRD(RC

Measurement of e+e−→γχcJe^+e^- \to \gamma\chi_{cJ} via initial state radiation at Belle

The process $e^+e^- \to \gamma\chi_{cJ}$ ($J$=1, 2) is studied via initial state radiation using 980 fb$^{-1}$ of data at and around the $\Upsilon(nS)$ ($n$=1, 2, 3, 4, 5) resonances collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. No significant signal is observed except from $\psi(2S)$ decays. Upper limits on the cross sections between $\sqrt{s}=3.80$ and $5.56~{\rm GeV}$ are determined at the 90% credibility level, which range from few pb to a few tens of pb. We also set upper limits on the decay rate of the vector charmonium [$\psi(4040$), $\psi(4160)$, and $\psi(4415)$] and charmoniumlike [$Y(4260)$, $Y(4360)$, and $Y(4660)$] states to $\gamma\chi_{cJ}$.Comment: Accepted by PR