14,277 research outputs found
Measurement of D0-D0bar mixing and search for CP violation in D0 -> K+K-, pi+pi- decays with the full Belle data set
We report an improved measurement of D0-D0bar mixing and a search for CP
violation in D0 decays to CP-even final states K+K- and pi+pi-. The measurement
is based on the final Belle data sample of 976/fb. The results are y_CP=(1.11
+- 0.22 +- 0.09)% and A_Gamma=(-0.03 +- 0.20 +- 0.07)%, where the first
uncertainty is statistical and the second is systematic.Comment: 8 pages, 5 figures; submitted to Phys. Lett.
Study of X(3872) in meson decays
We present results on the X(3872), produced in and decays where . We report the
first statistically significant observation of and
measure the ratio of branching fractions to be ,
consistent with unity. The mass difference between the X(3872) states produced
in and decay is found to be MeV/, consistent with zero. In addition, we
search for the X(3872) in the decay , . We measure and we set the 90% C.L. limit, . The analysis is based on a 605 fb data sample collected
at the with the Belle detector at the KEKB collider.Comment: 10 pages, 5 figures, Contributed to the 34th International Conference
On High Energy Physics (ICHEP 2008
Hadronic Mass Moments in B -> X_c l nu Decays
We report measurements of the first and second moments of the hadronic
invariant mass squared distribution, and )^2>, in B ->
X_c l nu decays for minimum lepton momenta ranging from 0.7 to 1.5 GeV/c in the
B meson rest frame. The measurement uses BBbar events in which the hadronic
decay of one B meson is fully reconstructed and the semileptonic decay of the
other B is inferred from the presence of an identified lepton. These results
are obtained from a 140 fb^-1 data sample collected near the Y(4S) resonance
with the Belle detector at the KEKB asymmetric energy e^+e^- collider.Comment: 9 pages, 2 figures, 4 tables, contributed to Lepton Photon and EPS
200
Measurement of D0 -> pilnu (Klnu) and their form factors
Using a data sample of 282 1/fb collected by the Belle experiment at the KEKB
e+e- collider, we study D0 -> pilnu and D0 -> Klnu decays (l = mu,e) in e+e-
annihilation. We identify D* -> D0pi decays by using the mass of the system
recoiling against a fully reconstructed tag-side D* or D meson, allowing for
additional primary mesons from fragmentation.
Using a novel global reconstruction method that provides very good resolution
in neutrino momentum and in q^2 = (p_l+p_nu)^2, we reconstructed D0 -> pilnu
and D0 -> Klnu decays. From these events we measured the branching fraction
ratios BR(D0 -> pienu)/BR(D0 -> Kenu) = 0.0809 +- 0.0080 +- 0.0032$ and BR(D0
-> pimunu)/BR(D0 -> Kmunu) = 0.0677 +- 0.0078 +- 0.0047, and the semileptonic
form factor ratio f+(D0 -> pilnu})^2/f+(D0 -> Klnu})^2|Vcd|^2/|Vcs|^2|_{q^2=0}
= 0.041 +- 0.003 +- 0.004, where the errors are statistical and systematic,
respectively.Comment: 20 pages, 8 figures; corrected form factor rati
Measurement of the angle \phi_3 with Dalitz analysis of three-body D^0 decay from B\to D^0 K process
A new method to measure the angle of the CKM unitarity triangle
using a Dalitz analysis of the three-body decay of the meson from the
process has been introduced recently. The method employs the
interference between and to extract both the weak and strong
phases. We present a study of statistical and systematic errors of this method
using Monte Carlo simulation. A fit of the Dalitz distribution has been
performed based on a 140 fb sample collected by the Belle detector. We
observe the indication of a CP asymmetry with the significance of 2.4 standard
deviations. The 90% confidence interval obtained for the value is
.Comment: 25 pages, 14 figures, contributed paper at Lepton Photon 200
Abstracting Probabilistic Models: A Logical Perspective
Abstraction is a powerful idea widely used in science, to model, reason and
explain the behavior of systems in a more tractable search space, by omitting
irrelevant details. While notions of abstraction have matured for deterministic
systems, the case for abstracting probabilistic models is not yet fully
understood.
In this paper, we provide a semantical framework for analyzing such
abstractions from first principles. We develop the framework in a general way,
allowing for expressive languages, including logic-based ones that admit
relational and hierarchical constructs with stochastic primitives. We motivate
a definition of consistency between a high-level model and its low-level
counterpart, but also treat the case when the high-level model is missing
critical information present in the low-level model. We prove properties of
abstractions, both at the level of the parameter as well as the structure of
the models. We conclude with some observations about how abstractions can be
derived automatically.Comment: In AAAI Workshop: Statistical Relational Artificial Intelligence,
2020. (This is the extended version.
Moments of the Electron Energy Spectrum in B --> X_c l \nu decays at Belle
We report a measurement of the inclusive electron energy spectrum for charmed
semileptonic decays of B mesons in a 140 fb^-1 data sample collected on the
Upsilon(4S) resonance, with the Belle detector at the KEKB asymmetric energy
e^+ e^- collider. We determine the first, second and third moments of the
electron energy spectrum for threshold values of the electron energy between
0.4 and 1.5 GeV.Comment: 13 pages, 3 figures, 6 tables, contributed to HEP2005 International
Europhysics Conference on High Energy Physic
Moments of the Hadronic Mass Spectrum in Inclusive Semileptonic B Decays at Belle
We report a measurement of the first and second moment of the hadronic mass
distribution M_X in B -> X_c l nu decays for lepton threshold momenta ranging
from 0.9 to 1.6 GeV/c in the center of mass frame. The measurement uses B Bbar
events in which the hadronic decay of one B meson is fully reconstructed and a
charged lepton from the decay of the other B meson is identified. These results
are obtained from a 140 fb^-1 data sample collected near the Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric energy e^+ e^-
collider.Comment: 9 pages, 3 figures, submitted to ICHEP2004, Beijing, Chin
Observation of h_b(1P)->eta_b(1S)gamma
We report the first observation of the radiative transition
h_b(1P)->eta_b(1S)gamma, where the h_b(1P) is produced in
Upsilon(5S)->h_b(1P)pi+pi- dipion transitions. We measure the eta_b(1S) mass to
be (9401.0+-1.9+1.4-2.4)MeV/c^2 with a width of (12.4+5.5-4.6+11.5-3.4)MeV and
a decay branching fraction of
BF[h_b(1P)->eta_b(1S)gamma]=(49.8+-6.8+10.9-5.2)%. The measured eta_b(1S) mass
corresponds to a hyperfine splitting of (59.3+-1.9+2.4-1.4)MeV/c^2. This value
deviates significantly from the current world average obtained from
measurements of Upsilon(3S)->eta_b(1S)gamma and Upsilon(2S)->eta_b(1S)gamma
reactions. We also report updated results for the h_b(1P) mass
(9899.0+-0.4+-1.0)MeV/c^2 and its hyperfine splitting (0.8+-1.1)MeV/c^2. These
measurements are performed using a 121.4fb^-1 data sample collected at the peak
of the Upsilon(5S) resonance with the Belle detector at the KEKB
asymmetric-energy e+e- collider.Comment: Prepared for International Workshop on Heavy Quarkonium 2011 (QWG
2011), GSI, Darmstadt, Germany, 4-7 Oct 201
Measurement of the branching fractions for and decays
We present a study of and
decays based on a sample of events collected with
the Belle detector at the KEKB asymmetric-energy collider. We measure
the branching fractions to be and D_s^+R_{D^*\pi}R_{D^*\pi}B^0 \to D^{*+}\pi^-B^0 \to
D^{*-}\pi^+$ decay.Comment: 6 pages, 2 figures, 2 tables. Submitted to PRD (RC
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