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Li, L. K.*; 谷田 聖; Belle Collaboration*; 他197名*
Physical Review D, 107(3), p.033003_1 - 033003_9, 2023/02
被引用回数:0 パーセンタイル:0.00(Astronomy & Astrophysics)We present measurements of the branching fractions for the singly Cabibbo-suppressed decays and
, and the doubly Cabibbo-suppressed decay
, based on 980
of data recorded by the Belle experiment at the KEKB
collider. We measure these modes relative to the Cabibbo-favored modes
and
. Our results for the ratios of branching fractions are
,
, and
, where the uncertainties are statistical and systematic, respectively. The second value corresponds to
, where
is the Cabibbo angle; this value is larger than other measured ratios of branching fractions for a doubly Cabibbo-suppressed charm decay to a Cabibbo-favored decay. Multiplying these results by world average values for
and
yields
,
, and
, where the third uncertainty is due to the branching fraction of the normalization mode. The first two results are consistent with, but more precise than, the current world averages. The last result is the first measurement of this branching fraction.
Li, S. X.*; 谷田 聖; Belle Collaboration*; 他197名*
Journal of High Energy Physics (Internet), 2022(3), p.90_1 - 90_11, 2022/03
被引用回数:8 パーセンタイル:58.61(Physics, Particles & Fields)We present the first measurement of the branching fraction of the singly Cabibbo-suppressed (SCS) decay with
, using a data sample corresponding to an integrated luminosity of 981
, collected by the Belle detector at the KEKB
asymmetric-energy collider. A significant
signal is observed for the first time with a signal significance of 5.4
. The relative branching fraction with respect to the normalization mode
is measured to be
,where the uncertainties are statistical and systematic, respectively. Using the world-average value of
, we obtain
,where the uncertainties are statistical, systematic, and from
, respectively.
Nisar, N. K.*; 谷田 聖; Belle Collaboration*; 他197名*
Physical Review D, 104(3), p.L031101_1 - L031101_8, 2021/08
被引用回数:1 パーセンタイル:6.87(Astronomy & Astrophysics)We report the results of the first search for the decay using
of data collected at the
resonance with the Belle detector at the KEKB asymmetric-energy
collider. We observe no significant signal and set a 90% confidence-level upper limit of
on the branching fraction of this decay.
Acharya, U.*; 長谷川 勝一; 今井 憲一*; 永宮 正治*; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他397名*
Physical Review C, 102(6), p.064905_1 - 064905_13, 2020/12
被引用回数:6 パーセンタイル:49.74(Physics, Nuclear)The PHENIX experiment at the Relativistic Heavy Ion Collider measured and
mesons at midrapidity in U
U collisions at
GeV in a wide transverse momentum range. Measurements were performed in the
decay modes. A strong suppression of
and
meson production at high transverse momentum was observed in central U
U collisions relative to binary scaled
results. Yields of
and
mesons measured in U
U collisions show similar suppression pattern to the ones measured in Au
Au collisions at
GeV for similar numbers of participant nucleons. The
/
ratios do not show dependence on centrality or transverse momentum, and are consistent with previously measured values in hadron-hadron, hadron-nucleus, nucleus-nucleus, and
collisions.
Aidala, C.*; 長谷川 勝一; 今井 憲一*; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他297名*
Physical Review C, 101(3), p.034910_1 - 034910_16, 2020/03
被引用回数:18 パーセンタイル:84.46(Physics, Nuclear)The PHENIX experiment has studied nuclear effects in Al and
Au collisions at
GeV on charged hadron production at forward rapidity (
,
-going direction) and backward rapidity (
,
-going direction). Such effects are quantified by measuring nuclear modification factors as a function of transverse momentum and pseudorapidity in various collision multiplicity selections. In central
Al and
Au collisions, a suppression (enhancement) is observed at forward (backward) rapidity compared to the binary scaled yields in
+
collisions. The magnitude of enhancement at backward rapidity is larger in
Au collisions than in
Al collisions, which have a smaller number of participating nucleons. However, the results at forward rapidity show a similar suppression within uncertainties. The results in the integrated centrality are compared with calculations using nuclear parton distribution functions, which show a reasonable agreement at the forward rapidity but fail to describe the backward rapidity enhancement.
Kaliyar, A. B.*; 谷田 聖; Belle Collaboration*; 他197名*
Physical Review D, 99(3), p.031102_1 - 031102_9, 2019/02
被引用回数:3 パーセンタイル:16.95(Astronomy & Astrophysics)We study charmless hadronic decays of charged mesons to the final states
and
using a
data sample that contains
pairs, and was collected at the
resonance with the Belle detector at the KEKB asymmetric-energy
collider. For
, the measured branching fraction and direct
asymmetry are
and [
]%, respectively. In the absence of a statistically significant signal for
, we obtain a 90% confidence-level upper limit on its branching fraction as
.
Berger, M.*; 谷田 聖; Belle Collaboration*; 他197名*
Physical Review D, 98(11), p.112006_1 - 112006_10, 2018/12
被引用回数:7 パーセンタイル:33.11(Astronomy & Astrophysics)We report measurements of the branching fractions of the decays ,
and
relative to the reference channel
. The analysis is based on the full data sample collected at and close to
resonance by the Belle detector at the KEKB asymmetric-energy
collider corresponding to the integrated luminosity of 711 fb
. We measure
,
and
. The listed uncertainties are statistical and systematic, respectively.
Fulsom, B. G.*; 谷田 聖; Belle Collaboration*; 他197名*
Physical Review Letters, 121(23), p.232001_1 - 232001_8, 2018/12
被引用回数:5 パーセンタイル:38.02(Physics, Multidisciplinary)We report the observation of decay based on analysis of the inclusive photon spectrum of
fb
of
collisions at the
center-of-mass energy collected with the Belle detector at the KEKB asymmetric-energy
collider. We measure a branching fraction of
, and derive an
mass of
MeV/
, where the uncertainties are statistical and systematic, respectively. The significance of our measurement is greater than 7 standard deviations, constituting the first observation of this decay mode.
Aidala, C.*; 長谷川 勝一; 今井 憲一; 永宮 正治*; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他397名*
Physical Review C, 98(5), p.054903_1 - 054903_11, 2018/11
被引用回数:14 パーセンタイル:71.21(Physics, Nuclear)Production of and
mesons has been measured at midrapidity in Cu
Au collisions at
=200 GeV. Measurements were performed in
decay channel in the 1(2)-20 GeV/
transverse momentum range. A strong suppression is observed for
and
meson production at high transverse momentum in central Cu
Au collisions relative to the
results scaled by the number of nucleon-nucleon collisions. In central collisions the suppression is similar to Au
Au with comparable nuclear overlap. The
ratio measured as a function of transverse momentum is consistent with
-scaling parameterization down to
2 GeV/
, its asymptotic value is constant and consistent with Au
Au and
and does not show any significant dependence on collision centrality. Similar results were obtained in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions as well as in
collisions in a range of collision energies
3-1800 GeV. This suggests that the quark-gluon-plasma medium produced in Cu
Cu collisions either does not affect the jet fragmentation into light mesons or it affects the
and
the same way.
Babu, V.*; 谷田 聖; Belle Collaboration*; 他197名*
Physical Review D, 97(1), p.011101_1 - 011101_8, 2018/01
被引用回数:11 パーセンタイル:46.13(Astronomy & Astrophysics)We search for violation in the charged charm meson decay
, based on a data sample corresponding to an integrated luminosity of
collected by the Belle experiment at the KEKB
asymmetric-energy collider. The measured
violating asymmetry is
, which is consistent with the standard model prediction and has a significantly improved precision compared to previous results.
Adare, A.*; 長谷川 勝一; 今井 憲一; 永宮 正治; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他497名*
Physical Review C, 96(2), p.024907_1 - 024907_19, 2017/08
被引用回数:11 パーセンタイル:61.57(Physics, Nuclear)We report a measurement of pairs from semileptonic heavy-flavor decays in
collisions at
= 200 GeV. The
pair yield from
and
is separated by exploiting a double differential fit done simultaneously in dielectron invariant mass and
. We used three different event generators,
,
, and
, to simulate the
spectra from
and
production. The data can be well described by all three generators within the detector acceptance. However, when using the generators to extrapolate to
, significant differences are observed for the total cross section. These difference are less pronounced for
than for
. The same model dependence was observed in already published
data. The
data are also directly compared with
data in mass and
, and within the statistical accuracy no nuclear modification is seen.
Thalmeier, R.*; 谷田 聖; 他97名*
Nuclear Instruments and Methods in Physics Research A, 845, p.633 - 638, 2017/02
被引用回数:6 パーセンタイル:45.73(Instruments & Instrumentation)The Belle II Experiment at the High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan, will explore the asymmetry between matter and antimatter and search for new physics beyond the standard model. 172 double-sided silicon strip detectors are arranged cylindrically in four layers around the collision point to be part of a system which measures the tracks of the collision products of electrons and positrons. A total of 1748 radiation-hard APV25 chips read out 128 silicon strips each and send the analog signals by time-division multiplexing out of the radiation zone to 48 Flash Analog Digital Converter Modules (FADC). Each of them applies processing to the data; for example, it uses a digital finite impulse response filter to compensate line signal distortions, and it extracts the peak timing and amplitude from a set of several data points for each hit, using a neural network. We present an overview of the SVD data readout system, along with front-end electronics, cabling, power supplies and data processing.
Adamczyk, K.*; 谷田 聖; Belle-II SVD Collaboration*; 他97名*
Nuclear Instruments and Methods in Physics Research A, 845, p.38 - 42, 2017/02
被引用回数:2 パーセンタイル:17.39(Instruments & Instrumentation)The Belle II experiment at the asymmetric SuperKEKB collider in Japan will operate at an instantaneous luminosity approximately 50 times greater than its predecessor (Belle). The central feature of the experiment is a vertex detector comprising two layers of pixelated silicon detectors (PXD) and four layers of double-sided silicon microstrip detectors (SVD). One of the key measurements for Belle II is CP violation asymmetry in the decays of beauty and charm hadrons, which hinges on a precise charged-track vertex determination and low-momentum track measurement. Towards this goal, a proper assembly of the SVD components with precise alignment ought to be performed and the geometrical tolerances should be checked to fall within the design limits. We present an overview of the assembly procedure that is being followed, which includes the precision gluing of the SVD module components, wire-bonding of the various electrical components, and precision 3D coordinate measurements of the final SVD modules.
Adare, A.*; 長谷川 勝一; 今井 憲一; 永宮 正治; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他397名*
Physical Review C, 94(5), p.054910_1 - 054910_18, 2016/11
被引用回数:27 パーセンタイル:84.20(Physics, Nuclear)Measurements of anisotropic flow Fourier coefficients () for inclusive charged particles and identified hadrons
,
,
, and
produced at midrapidity in Cu+Au collisions at
= 200 GeV are presented. The data were collected in 2012 by the PHENIX experiment at the Relativistic Heavy-Ion Collider (RHIC). The particle azimuthal distributions with respect to different-order symmetry planes
, for
1, 2, and 3 are studied as a function of transverse momentum
over a broad range of collision centralities. Mass ordering, as expected from hydrodynamic flow, is observed for all three harmonics. The charged-particle results are compared with hydrodynamical and transport model calculations. We also compare these Cu+Au results with those in Cu+Cu and Au+Au collisions at the same
and find that the
and
, as a function of transverse momentum, follow a common scaling with
.
Adare, A.*; 長谷川 勝一; 今井 憲一; 永宮 正治; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他397名*
Physical Review C, 93(3), p.034903_1 - 034903_12, 2016/03
被引用回数:10 パーセンタイル:57.09(Physics, Nuclear)The invariant yields, , for
production at forward rapidity (
) in U+U collisions at
= 193 GeV have been measured as a function of collision centrality. The invariant yields and nuclear-modification factor
are presented and compared with those from Au + Au collisions in the same rapidity range. Additionally, the direct ratio of the invariant yields from U + U and Au + Au collisions within the same centrality class is presented, and used to investigate the role of
coalescence. Two different parametrizations of the deformed Woods-Saxon distribution were used in Glauber calculations to determine the values of the number of nucleon-nucleon collisions in each centrality class,
, and these were found to give significantly different
values. Results using
values from both deformed Woods-Saxon distributions are presented. The measured ratios show that the
suppression, relative to binary collision scaling, is similar in U + U and Au + Au for peripheral and midcentral collisions, but that
show less suppression for the most central U + U collisions. The results are consistent with a picture in which, for central collisions, increase in the
yield due to
coalescence becomes more important than the decrease in yield due to increased energy density. For midcentral collisions, the conclusions about the balance between
coalescence and suppression depend on which deformed Woods-Saxon distribution is used to determine
.
Bhardwaj, V.*; 谷田 聖; Belle Collaboration*; 他197名*
Physical Review D, 93(5), p.052016_1 - 052016_13, 2016/03
被引用回数:23 パーセンタイル:67.49(Astronomy & Astrophysics)We report inclusive and exclusive measurements for and
production in
decays. We measure
and
. For the first time,
production in exclusive
decays in the modes
and
has been observed, along with first evidence for the
decay mode. For
production, we report the first observation in the
,
and
decay modes. Using these decay modes, we observe a difference in the production mechanism of
in comparison to
in
decays. In addition, we report searches for
and
in the
decay mode. The reported results use
events collected at the
resonance with the Belle detector at the KEKB asymmetric-energy
collider.