44,116 research outputs found
Direct test of time reversal invariance violation in B mesons
In this letter we reinterpret and reanalyze the available data of the B meson
factories showing the existence of direct experimental evidence of time
reversal invariance violation in B mesons. This reinterpretation consists of
using the available observables to define a new observable which, in a model
independent way and without assuming CPT invariance, compares a transition
between a and a here-defined -state, with its time reversed
transition. The observable then offers a direct way to probe time reversal
invariance and it is therefore independent of any conclusion obtained from
current experimental information on CP violation and CPT invariance. As far as
the authors are concerned, this is the first direct evidence of time reversal
invariance violation in B mesons and also the first one obtained from decaying
particles whose mean life time difference is negligible.Comment: 9 pages, no figures. Refined version matching published article in
Modern Physics Letters
Standard Model Higgs and Top Mass Measurements at the Tevatron
A summary of the present Standard Model Higgs search and measurement of top
quark mass at the Tevatron are presented. The sensitivity of the present Higgs
search at the Tevatron is limited by statistics to a cross section
approximately two orders of magnitude higher than the predicted cross section
for Standard Model Higgs production. With 30/fb of integrated luminosity, the
Tevatron offers an unique potential discovery window for the Standard Model
Higgs mass up to 130 GeV before LHC era. The study of top at the Tevatron has
moved from discovery phase to one of characterizing its properties. The
combined result of top quark mass is 174.3+- 5.1 GeV.Comment: 7 pages, latex source-file, 5 figures as ps-file. Talk given at The
Division of Particles and Fields Conference 1999, January 5-9, 1999, UCLA,
US
Quark and lepton mass matrices with family symmetry
Realistic quark masses and mixing angles are obtained applying the successful
family symmetry for leptons, motivated by the quark-lepton assignments of
SU(5). The symmetry is suitable to give tri-bimaximal neutrino mixing
matrix which is consistent with current experimental data. We study new
scenario for the quark sector with the symmetry.Comment: 16 pages, 2 figures, Talk given at International Workshop on Neutrino
Masses and Mixings, Shizuoka, Japan, 17-19 December 200
Charm mixing in the Standard Model and beyond
The motivation most often cited in searches for D0-anti-D0 mixing and
CP-violation in charm system lies with the possibility of observing a signal
from New Physics which dominates that from the Standard Model. We review recent
theoretical predictions and experimental constraints on D0-anti-D0 mixing
parameters, concentrating on possible effects of New Physics.Comment: 8 pages, 2 figures, Invited talk at International Workshop on
Tau-Charm Physics (Charm 2006), Beijing, China, 5-7 Jun 200
Shell Cracking In Investment Casting with Laser Stereolithography Patterns
This paper presents an investigation of ceramic shell cracking during the burnout process
in investment casting with internally webbed laser stereolithography patterns. We hypothesize
that shell cracking will occur when the rupture temperature of the ceramic shell is lower than
both the glass transition temperature of the pattern material and the web· link buckling
temperature. The hypothesis is validated by our experimental observations which confirm the
numerical predictions from our fillite element analysis. This provides a basis for design of the
internal web geometry of a lithography pa.tternand evaluation ofthe burnolltprocesswithsuch a
pattern. We show the shell cracking and web link buckling temperatures to be functiollsofthe
pattern geometry (including the cross~sectional dimensions and span length of the web link) and
the shell thickness.Mechanical Engineerin
Search for Rare b-hadron Decays at CDF
We report on searches for B^0_s to \mu^+ \mu^-, B^0_d to \mu^+ \mu^- decays
and b to s \mu^+\mu^- transitions in exclusive decays of B mesons.
Using 2 fb^{-1} of data collected by the CDF II detector we find upper limits
on the branching fractions B(B^0_s to \mu^+ \mu^-) < 5.8 x 10^{-8} and B(B^0_d
to \mu^+ \mu^-) < 1.8 x 10^{-8} at 95% confidence level.
Using 924 pb^{-1} of data we measure the branching fractions B(B^+ to \mu^+
\mu^- K^+) = (0.60 \pm 0.15 \pm 0.04) x 10^{-6}, B(B^0_d to \mu^+ \mu^- K^{*0})
= (0.82 \pm 0.31 \pm 0.10) x 10^{-6} and the limit B(B^0_s to \mu^+ \mu^-
phi)/B(B^0_s to J/\psi\phi) < 2.61(2.30) x 10^{-3} at 95(90)% confidence level.Comment: 3 pages, 5 figures, conference proceedings to the 2007 Europhysics
Conference on High Energy Physics (Manchester, July 2007
Final stare interaction enhancement effect on the near threshold p\bar p system in B^\pm\to p\bar p \p^\pm decay
We discuss the low-mass enhancement effect in the baryon-antibaryon invariant
mass in three-body baryonic B decays using final state interactions in the
framework of Regge theory. We show that the rescattering between baryonic pair
can reproduce the observed mass spectrum.Comment: 7 pages, 11 figure
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