125 research outputs found
Women in Leadership: They Persist
This Spotlight Presentation features the expertise of higher education leaders at different stages of their career. These individuals pursued unique professional pathways within different educational contexts and been exposed to opportunities and challenges calling for a range of problem-solving skills. They will share experiences, what it means to advocate for oneself as a leader, for others, and how to create conditions for sustainable change supporting inclusivity within the complex, shifting landscape of higher education
Measurement of the mixing rate with partial reconstruction
We report a measurement of the mixing parameter
based on a sample of resonance decays
collected by the Belle detector at the KEKB asymmetric collider. We
use events with a partially reconstructed candidate and where the flavor of the accompanying meson is
identified by the charge of the lepton from a decay. The proper-time difference between the two mesons is
determined from the distance between the two decay vertices. From a
simultaneous fit to the proper-time distributions for the same-flavor
(, ) and opposite-flavor (,
) event samples, we measure the mass difference between the two
mass eigenstates of the neutral meson to be = .Comment: 16 pages, 14 figure
Evidence for CP-Violating Asymmetries in B0->pi+pi- Decays and Constraints on the CKM Angle phi2
We present an improved measurement of CP-violating asymmetries in B0 -> pi+
pi- decays based on a 78 fb^-1 data sample collected at the Y(4S) resonance
with the Belle detector at the KEKB asymmetric-energy e+e- collider. We
reconstruct one neutral B meson as a B0 -> pi+ pi- CP eigenstate and identify
the flavor of the accompanying B meson from inclusive properties of its decay
products. We apply an unbinned maximum likelihood fit to the distribution of
the time intervals between the two B meson decay points. The fit yields the
CP-violating asymmetry amplitudes Apipi = +0.77+/-0.27(stat)+/-0.08(syst) and
Spipi = -1.23+/-0.41(stat)+0.08/-0.07(syst), where the statistical
uncertainties are determined from Monte Carlo pseudo-experiments. We obtain
confidence intervals for CP-violating asymmetry parameters Apipi and Spipi
based on a frequentist approach. We rule out the CP-conserving case,
Apipi=Spipi=0, at the 99.93% confidence level. We discuss how these results
constrain the value of the CKM angle phi2.Comment: 26 pages, 13 figures, submitted to Phys. Rev.
Observation of the DsJ(2317) and DsJ(2457) in B decays
We report the first observation of the B --> Dbar DsJ(2317) and B --> Dbar
DsJ(2457) decays based on 123.8 10^6 BBar events collected with the Belle
detector at KEKB. We observe the DsJ(2317) decay to Ds pi0 and DsJ(2457) decay
to the Ds* pi0 and Ds gamma final states. We also set 90% CL upper limits for
the decays DsJ(2317) --> Ds* gamma, DsJ(2457) --> Ds* gamma, DsJ(2457) --> Ds
pi0 and DsJ(2457) --> Ds pi+ pi-.Comment: 6 pages, 3 figures. A few minor corrections. Replaced by version
accepted to publication in Phys. Rev. Let
Precise Measurement of B Meson Lifetimes with Hadronic Decay Final States
The lifetimes of the B0bar and B- mesons are extracted from 29.1/fb of data
collected with the Belle detector at the KEK B-factory. A fit to the decay
length differences of neutral and charged B meson pairs, measured in events
where one of the B mesons is fully reconstructed in several hadronic modes,
yields tau_B0bar = 1.554 +/- 0.030(stat) +/- 0.019(syst) ps, tau_B- = 1.695 +/-
0.026(stat) +/- 0.015(syst) ps, and tau_B-/tau_B0bar = 1.091 +/- 0.023(stat)
+/- 0.014(syst).Comment: 10 pages, 2 figures, and 1 table. (To be) published in Phys. Rev.
Let
Mesurement of the B0 - anti-B0 Mixing Parameter Delta m_d using Semileptonic B0 Decays
We present a measurement of the B^0-B^0bar mixing parameter Delta m_d using
neutral B meson pairs in a 29.1 fb^{-1} data sample collected at the
Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy
e^+e^- collider. We exclusively reconstruct one neutral B meson in the
semileptonic B^0 \to D^{*-}\ell^+\nu decay mode and identify the flavor of the
accompanying B meson from its decay products. From the distribution of the time
intervals between the two flavor-tagged B meson decay points, we obtain Delta
m_d = (0.494 +- 0.012 +- 0.015) ps^{-1}, where the first error is statistical
and the second error is systematic.Comment: 10 pages, 3 figures, Published in Phys.Rev.Lett. 89, 251803 (2002
Observation of B+- -> omega K+- Decay
We report the first observation of the charmless two-body mode decay, and a new measurement of the branching fraction for the
decay. The measured branching fractions are
and . %and we set 90% confidence
level upper limits of %.
We also measure the partial rate asymmetry of decays
and obtain . The results are based on
a data sample of 29.4 fb collected on the resonance by
the Belle detector at the KEKB collider.Comment: 5 pages, 4 figures, resubmitted to Phys. Rev. Let
Improved Measurement of the Partial-Rate CP Asymmetry in B+ -> K0pi+ and B- -> K0bar pi- Decays
We report an improved measurement of the partial-rate CP asymmetry in B+ =>
K0pi+ and B- => K0bar pi- decays. The analysis is based on a data sample of 85
million BBbar pairs collected at the Upsilon(4S) resonance with the Belle
detector at the KEKB e+ e- storage ring. We measure Acp(K0pi+-) = 0.07^{+0.09
+0.01}_{-0.08 -0.03}, where the first and second errors are statistical and
systematic, respectively; the corresponding 90% confidence-level interval is
-0.10 < Acp(K0pi+-) < 0.22 .Comment: 7 pages, 8 figures, submitted to Phys. Rev.
Observation of Ds+ K- and evidence for Ds+ pi- final states in neutral B decays
We report the first observation of a B meson decay that is not accessible by
a direct spectator process. The channel B0bar -> Ds+ K- is found in a sample of
85 timse 10^6 B Bbar events, collected with the Belle detector at KEKB, with a
branching fraction Br(B0bar -> Ds+ K-)=(4.6^{+1.2}_{-1.1} +- 1.3) times
10^{-5}. We also obtain evidence for the B0 -> Ds+ pi- decay with branching
fraction Br(B0 -> Ds+ pi-)=(2.4^{+1.0}_{-0.8} +- 0.7) times 10^{-5}. This value
may be used to extract a model-dependent value of |Vub|.Comment: Accepted to publication in Phys. Rev. Let
Study of Exclusive B decays to Charmed Baryons
Using 29.1fb-1 of data accumulated at the Upsilon(4S) with the Belle detector
at KEKB, we have studied the decay modes B0bar->Lambda_c+ pbar pi+pi-, B- ->
Lambda_c+ pbar pi-, and B0bar ->Lambda_c+ pbar. We report branching fractions
of exclusive B decays to charmed baryons with four-, three- and two-body final
states, including intermediate Sigma_c++ and Sigma_c0 states. We observed B0bar
-> Sigma_c(2455)++pbar pi- for the first time with a branching fraction of
(2.38+0.63-0.55+-0.41+-0.62)x10-4 and observed evidence for the two-body decay
B- ->Sigma_c(2455)0 pbar with a branching fraction of
(0.45+0.26-0.19+-0.07+-0.12)x10-4. We also set improved upper limits for the
two-body decays B0bar -> Lambda_c+ pbar and B- -> Sigma_c(2520)0 pbar.Comment: accepted for publication in Phys. Rev.
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