28 research outputs found
Search for B+ -> D*+ pi0 decay
We report on a search for the doubly Cabibbo suppressed decay B+ -> D*+ pi0,
based on a data sample of 657 million BBbar pairs collected at the Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric energy e+ e- collider.
We find no significant signal and set an upper limit of Br(B+ -> D*+ pi0) < 3.6
x 10^-6 at the 90% confidence level. This limit can be used to constrain the
ratio between suppressed and favored B -> D* pi decay amplitudes, r < 0.051, at
the 90% confidence level.Comment: 5pages, 2figures, submitted to PRL (v1); PRL published version (v2:
minor corrections in the text
Observation of the and the Y(2175) in
The cross sections for and e^+ e^- \to \phi
\fzero are measured from threshold to using
initial state radiation. The analysis is based on a data sample of 673
fb collected on and below the resonance with the Belle
detector at the KEKB asymmetric-energy collider. First measurements
are reported for the resonance parameters of the in the
mode: MeV/ and MeV/. A structure at ,
corresponding to the so called Y(2175), is observed; its mass and width are
determined to be MeV/ and , respectively.Comment: 11 pages, 6 figures. Add one plot. Accepted by Phys.Rev.D(RC
Measurement of CP asymmetry in Cabibbo suppressed D0 decays
We measure the CP-violating asymmetries in decays to the D0 -> K+K- and D0 ->
pi+pi- CP eigenstates using 540 fb^{-1} of data collected with the Belle
detector at or near the Upsilon(4S) resonance. Cabibbo-favored D0 -> K-pi+
decays are used to correct for systematic detector effects. The results,
A_{CP}^{KK} = (-0.43 +- 0.30 +- 0.11)% and A_{CP}^{pipi} = (+0.43 +- 0.52 +-
0.12)%, are consistent with no CP violation.Comment: Submitted to Phys. Lett.
A Low-Footprint Java-to-Native Compilation Scheme Using Formal Methods
Ahead-of-Time and Just-in-Time compilation are common ways to improve runtime performances of restrained systems like Java Card by turning critical Java methods into native code. However, native code is much bigger than Java bytecode, which severely limits or even forbids these practices for devices with memory constraints. In this paper, we describe and evaluate a method for reducing natively-compiled code by suppressing runtime exception check sites, which are emitted when compiling bytecodes that may potentially throw runtime exceptions. This is made possible by completing the Java program with JML annotations, and using a theorem prover in order to formally prove that the compiled methods never throw runtime exceptions. Runtime exception check sites can then safely be removed from the generated native code, as it is proved they will never be entered. We have experimented our approach on several card-range and embedded Java applications, and were able to remove almost all the exception check sites. Results show memory footprints for native code that are up to 70% smaller than the non-optimized version, and sometimes as low than 115% the size of the Java bytecode when compiled for ARM thumb
Study of \Omega_c^0 and \Omega_c^{*0} Baryons at Belle
We report results from a study of the charmed double strange baryons
\Omega_c^0 and \Omega_c^{*0} at Belle. The \Omega_c^0 is reconstructed using
the \Omega_c^0 --> \Omega^- \pi^+ decay mode, and its mass is measured to be
(2693.6 \pm 0.3 {+1.8 \atop -1.5}) MeV/c^2. The \Omega_c^{*0} baryon is
reconstructed in the \Omega_c^0 \gamma mode. The mass difference
M_{\Omega_c^{*0}} - M_{\Omega_c^0} is measured to be (70.7 \pm 0.9 {+0.1 \atop
-0.9}) MeV/c^2. The analysis is performed using 673 fb^{-1} of data on and near
the \Upsilon(4S) collected with the Belle detector at the KEKB
asymmetric-energy e^+e^- collider.Comment: 11 pages, 5 figures, prepared for 34th International Conference on
High Energy Physics (ICHEP 08), Philadelphia, PA, 29 Jul - 5 Aug 200
Measurement of cross sections of exclusive processes at GeV
The cross sections for the reactions have been measured using a data sample of 516
fb collected with the Belle detector at the KEKB asymmetric-energy
collider. The corresponding values of the cross sections are: fb , fb , fb and fb . The
energy dependence of the cross sections is presented using Belle measurements
together with those of CLEO and BaBar.Comment: 8 pages, 8 figure
Measurement of the Decay B_s^0 -> D_s^- pi^+ and Evidence for B_s^0 -> D_s^{+/-} K^{-/+} in e+e- Annihilation at sqrt(s)~10.87 GeV
We have studied Bs0 -> Ds- pi+ and Bs0 -> Ds^(-/+) K^(+/-) decays using 23.6
/fb of data collected at the Upsilon(5S) resonance with the Belle detector at
the KEKB e+e- collider.
This highly pure Bs0 -> Ds- pi+ sample is used to measure the branching
fraction, BR(Bs0 -> Ds- pi+)=[3.67 +0.35,-0.33}(stat.) +0.43,-0.42(syst.)
+-0.49(f_s)] x 10^{-3} (f_s=N(Bs(*) Bs(*)bar)/N(b\bar b)) and the fractions of
Bs0 event types at the Upsilon(5S) energy, {in particular N(Bs*
Bs*bar}/N(N(Bs(*) Bs(*)bar)=(90.1 +3.8,-4.0 +-0.2)%. We also determine the
masses M(Bs0)=(5364.4 +-1.3 +-0.7) MeV/c^2 and M(Bs*)=(5416.4 +-0.4 +-0.5)
MeV/c^2. In addition, we observe Bs0 -> Ds^(-/+) K^(+/-) decays with a
significance of 3.5\sigma and measure BR(Bs0 -> Ds^(-/+) K^(+/-))=[2.4
+1.2,-1.0(stat.) +-0.3(syst.) +-0.3(f_s)] x 10^{-4}.Comment: 5 pages, 4 figures, accepted by PR
Search for
We report a search for the decay , using a sample of 657
pairs collected with the Belle detector at the
resonance. No statistically significant signal is found and an
upper limit for the branching fraction is determined to be at 90% confidence level.Comment: 5 pages, 2 figures, 3 tables, submitted to PRD(RC
Evidence for Neutral B Meson Decays to wK*0
We present the results of a study of the charmless vector-vector decay
B0->wK*0 with 657x10^6 BB(bar) pairs collected with the Belle detector at the
KEKB e+e- collider. We measure the branching fraction to be
B(B0->wK*0)=[1.8+/-0.7(stat)+/-0.3(syst)]x10^-6 with 3.0sigma significance. We
also perform a helicity analysis of the w and K*0 vector mesons, and obtain the
longitudinal polarization fraction
fL(B0->wK*0)=0.56+/-0.29(stat)+0.18-0.08(syst). Finally, we measure a large
non-resonant branching fraction B[B->wK+pi-; M(Kpi)\in(0.755,1.250)
GeV/c^2]=[5.1+/-0.7(stat)+/-0.7(syst)]x10^-6 with a significance of 9.5sigma.Comment: 6 pages, 3 figures (7 figure files
Observation of and search for direct CP-violation
We report the first observation of , a Cabibbo-
and color-suppressed decay. This analysis is based on
events collected at the resonance with the Belle
detector at the KEKB energy-asymmetric collider. The measured
branching fraction is () and the charge
asymmetry is . The ratio of the
branching fractions is also
determined.Comment: 6 pages, 3 figures, submitted to PRD(RC