1,263 research outputs found
First Observation of the Hadronic Transition ΄(4S)âηhb(1P) and New Measurement of the hb(1P) and ηb(1S) Parameters
Using a sample of 771.6Ă106 ΄΄(4S) decays collected by the Belle experiment at the KEKB e+eâ collider, we observe, for the first time, the transition ΄(4S)âηhb(1P) with the branching fraction B[΄(4S)âηhb(1P)]=(2.18±0.11±0.18)Ă10â3 and we measure the hb(1P) mass Mhb(1P)=(9899.3±0.4±1.0)ââMeV/c2, corresponding to the hyperfine (HF) splitting ÎMHF(1P)=(0.6±0.4±1.0)ââMeV/c2. Using the transition hb(1P)âγηb(1S), we measure the ηb(1S) mass Mηb(1S)=(9400.7±1.7±1.6)ââMeV/c2, corresponding to ÎMHF(1S)=(59.6±1.7±1.6)ââMeV/c2, the ηb(1S) width Îηb(1S)=(8+6â5±5)ââMeV/c2 and the branching fraction B[hb(1P)âγηb(1S)]=(56±8±4)%
Inclusive study of bottomonium production in association with an η meson in e+eâ annihilations near ΄(5S)
We study bottomonium production in association with an η meson in e+eâ annihilations near the ΄(5S), at a center of mass energy of sâ=10.866GeV. The results are based on the 121.4fbâ1 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+eââη΄J(1D) process and find evidence for the e+eââη΄(2S) process, while no significant signals of ΄(1S), hb(1P), nor hb(2P) are found. Cross sections for the studied processes are reported
First Observation of the Hadronic Transition ΄(4S)âηhb(1P)and New Measurement of the hb(1P) and ηb(1S) Parameters
Using a sample of 771.6Ă106 ΄΄(4S) decays collected by the Belle experiment at the KEKB e+eâ collider, we observe, for the first time, the transition ΄(4S)âηhb(1P) with the branching fraction B[΄(4S)âηhb(1P)]=(2.18±0.11±0.18)Ă10â3 and we measure the hb(1P) mass Mhb(1P)=(9899.3±0.4±1.0)ââMeV/c2, corresponding to the hyperfine (HF) splitting ÎMHF(1P)=(0.6±0.4±1.0)ââMeV/c2. Using the transition hb(1P)âγηb(1S), we measure the ηb(1S) mass Mηb(1S)=(9400.7±1.7±1.6)ââMeV/c2, corresponding to ÎMHF(1S)=(59.6±1.7±1.6)ââMeV/c2, the ηb(1S) width Îηb(1S)=(8+6â5±5)ââMeV/c2and the branching fraction B[hb(1P)âγηb(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 meson
decay-modes. The Full Event Interpretation algorithm enables many of these
measurements. The algorithm relies on machine learning to automatically
identify plausible 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 (2016â2017) 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 classiïŹed morphologically as fertile, sterile, caseous and calciïŹed. Protoscoleces and germinal layers were collected from individual cysts and DNA was extracted to identify diïŹerent 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 or , 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 at Belle
We report a search for the rare charmless decay
using a data sample of
pairs collected at the resonance with
the Belle detector at the KEKB asymmetric-energy collider. No
statistically significant signal is found and a 90% confidence-level upper
limit is set on the decay branching fraction as .Comment: 8 pages, 3 figures, submitted to PRD(RC
Measurement of via initial state radiation at Belle
The process (=1, 2) is studied via initial
state radiation using 980 fb of data at and around the
(=1, 2, 3, 4, 5) resonances collected with the Belle detector at the KEKB
asymmetric-energy collider. No significant signal is observed except
from decays. Upper limits on the cross sections between
and 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 [), , and
] and charmoniumlike [, , and ] states
to .Comment: Accepted by PR
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