466 research outputs found
Resolution Studies on Silicon Strip Sensors with fine Pitch
In June 2008 single-sided silicon strip sensors with 50 m readout pitch
were tested in a highly energetic pion beam at the SPS at CERN. The purpose of
the test was to evaluate characteristic detector properties by varying the
strip width and the number of intermediate strips. The experimental setup and
first results for the spatial resolution are discussed.Comment: proceeding of the International Linear Collider Workshop 2008
(LCWS08); corrected typos, added reference for section
Measurements of time-dependent CP asymmetries in decays using a partial reconstruction technique
We report results on time-dependent CP asymmetries in decays based on a data sample containing 657 {\times}
pairs collected with the Belle detector at the KEKB
asymmetric-energy collider at the resonance. We use a
partial reconstruction technique, wherein signal
events are identified using information only from the fast pion from the B
decay and the slow pion from the subsequent decay of the , where the
former (latter) corresponds to final states. We obtain CP
violation parameters and .Comment: 8 pages, 5 figures, 2 tables, submitted to Physical Review D (RC
Observation of Mixing in Collisions
We observe mixing in the decay
using a data sample of integrated luminosity 976 fb collected with the
Belle detector at the KEKB asymmetric-energy collider. We measure the
mixing parameters and and the ratio of doubly Cabibbo-suppressed to
Cabibbo-favored decay rates , where the
uncertainties are statistical and systematic combined. Our measurement excludes
the no-mixing hypothesis at the 5.1 standard deviation level.Comment: 6 pages, 4 figure
First Observation of Radiative B^0 -> \phi K^0 \gamma Decays and Measurements of Their Time-Dependent CP Violation
We report the first observation of the radiative decay B^0 -> \phi K^0 \gamma
using a data sample of 772 x 10^6 B B-bar pairs collected at the \Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric-energy e^+e^-
collider. We observe a signal of 37+/-8 events with a significance of 5.4
standard deviations including systematic uncertainties. The measured branching
fraction is , where the uncertainties are statistical and systematic, respectively.
We also report the first measurements of time-dependent CP violation
parameters: and . Furthermore, we measure , and find that the signal is concentrated in
the M_{\phi K} mass region near threshold.Comment: 6 pages, 3 figures, Modified version is to be published in PRD(RC
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
Search for the Glueball in and decays
We report the first search for the glueball in
and decays with data samples of million and
million events, respectively, collected with the Belle detector. No
significant signals are observed in any of the proposed production modes, and
the 90\% credibility level upper limits on their branching fractions in
and decays are obtained. The inclusive branching
fractions of the and decays into final states
with a are measured to be \BR(\Upsilon(1S)\to \chi_{c1}+ anything)
= (1.90\pm 0.43(stat.)\pm 0.14(syst.))\times 10^{-4} with an improved
precision over prior measurements and \BR(\Upsilon(2S)\to \chi_{c1}+ anything)
= (2.24\pm 0.44(stat.)\pm 0.20(syst.))\times 10^{-4} for the first time.Comment: 19 pages, 17 figures, Fig.10b was polished, but all the results
unchanged. Paper was published in PR
Search for B+ -> l+ nu gamma decays with hadronic tagging using the full Belle data sample
We search for the decay B+ -> l+ nu gamma with l+ = e+ or mu+ using the full
Belle data set of 772 x 10^6 BBbar pairs, collected at the Y(4S) resonance with
the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct
one B meson in a hadronic decay mode and search for the B+ -> l+ nu gamma decay
in the remainder of the event. We observe no significant signal within the
phase space of E_gamma^sig > 1 GeV and obtain upper limits of BR(B+ -> e+ nu
gamma) mu+ nu gamma) l+ nu
gamma) < 3.5 x 10^-6 at 90 % credibility level.Comment: Submitted to Phys. Rev.
Study of Excited States Decaying into and Baryons
Using a data sample of 980 of annihilation data
taken with the Belle detector operating at the KEKB asymmetric-energy
collider, we report the results of a study of excited states that
decay, via the emission of photons and/or charged pions, into or
ground state charmed-strange baryons. We present new measurements of
the masses of all members of the , ,
, , and isodoublets, measurements of
the intrinsic widths of those that decay strongly, and evidence of previously
unknown transitions.Comment: Submitted to PR
Inclusive cross sections for pairs of identified light charged hadrons and for single protons in at 10.58 GeV
We report the first double differential cross sections of two charged pions
and kaons () in electron-positron annihilation as a
function of the fractional energies of the two hadrons for any charge and
hadron combination. The dependence of these di-hadron cross sections on the
topology (same, opposite-hemisphere or anywhere) is also studied with the help
of the event shape variable thrust and its axis. The ratios of these di-hadron
cross sections for different charges and hadron combinations directly shed
light on the contributing fragmentation functions. For example, we find that
the ratio of same-sign pion pairs over opposite-sign pion pairs drops toward
higher fractional energies where disfavored fragmentation is expected to be
suppressed. These di-hadron results are obtained from a
data sample collected near the resonance with the Belle detector
at the KEKB asymmetric-energy collider. Extending the previously
published single-pion and single-kaon cross sections, single-proton () cross sections are extracted from a data
sub-sample.Comment: submitted to PR
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