3,866 research outputs found
Belle II iTOP Optics: Design, Construction and Performance
The imaging-Time-of-Propogation (iTOP) counter is a new type of ring-imaging
Cherenkov counter developed for particle identification at the Belle II
experiment. It consists of 16 modules arranged azimuthally around the beam
line. Each module consists of one mirror, one prism and two quartz bar
radiators. Here we describe the design, acceptance test, alignment, gluing and
assembly of the optical components. All iTOP modules have been successfully
assembled and installed in the Belle II detector by the middle of 2016. After
installation, laser and cosmic ray data have been taken to test the performance
of the modules. First results from these tests are presented.Comment: Proceedings of TIPP 2017, May 22 - 26, Beijing, China, 2017;
University of Cincinnati preprint UCHEP-17-07. arXiv admin note: text overlap
with arXiv:1709.0993
Search for lepton flavor violation via the intense high-energy muon beam
A deep inerastic scattering process \mutau is discussed to study lepton
flavor violation between muons and tau leptons. In supersymmetric models, the
Higgs boson mediated diagrams could be important for this reaction. We find
that at a muon energy () higher than 50 GeV, the predicted cross
section significantly increases due to the contribution from sea -quarks.
The number of produced tau leptons can be at = 300
GeV from muons, whereas events are given at
GeV.Comment: Contribution to the 6th International Workshop on Neutrino Factories
& Superbeams(NuFact04), Jul. 26-Aug. 1, 2004, Osaka Univerisity, Osaka,
Japan, talk given by S.K., to appear in the Proceedings, 3 pages, 4 figure
Cross-talk suppressed multi-anode MCP-PMT
We have developed a 4-channel multi-anode MCP-PMT, SL10, which exhibits a
performance of sigma_TTS ~ 30 ps for single photons with G ~ 10^6 and QE=20%
under a magnetic field of B <= 1.5 T. The cross-talk among anodes has been
extensively studied. We have taken two measures to suppress it: one is to
configure the SL10 to an effectively independent 4 small pieces of MCP-PMT's by
segmenting an electrode of the second MCP-layer; the other is to use a constant
fractional discriminator. Remarkable improvement has been achieved.Comment: 14 pages, 14 figure
An imaging time-of-propagation system for charged particle identification at a super B factory
Super B factories that will further probe the flavor sector of the Standard
Model and physics beyond will demand excellent charged particle identification
(PID), particularly K/pi separation, for momenta up to 4 GeV/c, as well as the
ability to operate under beam backgrounds significantly higher than current B
factory experiments. We describe an Imaging Time-of-Propagation (iTOP) detector
which shows significant potential to meet these requirements. Photons emitted
from charged particle interactions in a Cerenkov radiator bar are internally
reflected to the end of the bar, where they are collected on a compact image
plane using photodetectors with fine spatial segmentation in two dimensions.
Precision measurements of photon arrival time are used to enhance the two
dimensional imaging, allowing the system to provide excellent PID capabilities
within a reduced detector envelope. Results of the ongoing optimization of the
geometric and physical properties of such a detector are presented, as well as
simulated PID performance. Validation of simulations is being performed using a
prototype in a cosmic ray test stand at the University of Hawaii.Comment: 3 pages, 5 figures, submitted to TIPP09 proceeding
Spectral Correlation in Incommensurate Multi-Walled Carbon Nanotubes
We investigate the energy spectra of clean incommensurate double-walled
carbon nanotubes, and find that the overall spectral properties are described
by the so-called critical statistics of Anderson metal-insulator transition. In
the energy spectra, there exist three different regimes characterized by
Wigner-Dyson, Poisson, and semi-Poisson distributions. This feature implies
that the electron transport in incommensurate multi-walled nanotubes can be
either diffusive, ballistic, or intermediate between them, depending on the
position of the Fermi energy.Comment: final version to appear in Phys. Rev. Let
Study of B -> \rho \pi decays at Belle
This paper describes a study of B meson decays to the pseudoscalar-vector
final state \rho\pi using 31.9\times 10^6 B\bar{B} events collected with the
Belle detector at KEKB. The branching fractions B(B^+ \to \rho^0\pi^+) =
(8.0^{+2.3+0.7}_{-2.0-0.7}) \times 10^{-6} and B(B^0 -> \rho^{+-} \pi^{-+}) =
(20.8^{+6.0+2.8}_{-6.3-3.1}) \times 10^{-6} are obtained. In addition, a 90%
confidence level upper limit of B(B^0 \to \rho^0\pi^0) < 5.3 \times 10^{-6}is
reported.Comment: 14 pages, 3 figures, to be submitted to Phys. Lett.
Study of the Baryon-Antibaryon Low-Mass Enhancements in Charmless Three-body Baryonic B Decays
The angular distributions of the baryon-antibaryon low-mass enhancements seen
in the charmless three-body baryonic B decays B+ -> p pbar K+, B0 -> p pbar Ks,
and B0 -> p Lambdabar pi- are reported. A quark fragmentation interpretation is
supported, while the gluonic resonance picture is disfavored. Searches for the
Theta+ and Theta++ pentaquarks in the relevant decay modes and possible
glueball states G with 2.2 GeV/c2 < M-ppbar < 2.4 GeV/c2 in the ppbar systems
give null results. We set upper limits on the products of branching fractions,
B(B0 -> Theta+ p)\times B(Theta+ -> p Ks) Theta++
pbar) \times B(Theta++ -> p K+) G K+) \times
B(G -> p pbar) < 4.1 \times 10^{-7} at the 90% confidence level. The analysis
is based on a 140 fb^{-1} data sample recorded on the Upsilon(4S) resonance
with the Belle detector at the KEKB asymmetric-energy e+e- collider.Comment: 14 pages, 13 figure files, update of hep-ex/0409010 for journal
submisssio
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