130 research outputs found
Semibiotic Persistence
From observation, we find four different strategies to successfully enable structures to persist over extended periods of time. If functionally relevant features are very large compared to the changes that can be effectuated by entropy, the functional structure itself has a high enough probability to erode only slowly over time. If the functionally relevant features are protected from environmental influence by sacrificial layers that absorb the impinging of the environment,deterioration can be avoided or slowed. Loss of functionality can be delayed, even for complex systems, by keeping alternate options for all required components available. Biological systems also apply information processing to actively counter the impact of entropy. The latter strategy increases the overall persistence of living systems and enables them to maintain a highly complex functional organisation during their lifetime and over generations. In contrast to the other strategies, information processing has only low material overhead. While at present engineered technology is far from achieving the self-repair of evolved systems, the semibiotic combination of biological components with conventionally engineered systems may open a path to long-term persistence of functional devices in harsh environments. We review nature’s strategies for persistence, and consider early steps taken in the laboratory to import such capabilities into engineered architectures.<br/
Study of the decays B->D_s1(2536)+ anti-D(*)
We report a study of the decays B -> D_s1(2536)+ anti-D(*), where anti-D(*)
is anti-D0, D- or D*-, using a sample of 657 x 10^6 B anti-B pairs collected at
the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy
e+e- collider. The branching fractions of the decays B+ -> D_s1(2536)+ anti-D0,
B0 -> D_s1(2536)+ D- and B0 -> D_s1(2536)+ D*- multiplied by that of
D_s1(2536)+ -> (D*0K+ + D*+K0) are found to be (3.97+-0.85+-0.56) x 10^-4,
(2.75+-0.62+-0.36) x 10^-4 and (5.01+-1.21+-0.70) x 10^-4, respectively.Comment: 6 pages, 2 figues, submitted to PRD (RC
Search for CP Violation in the Decay
We search for CP violation in the decay using a
data sample with an integrated luminosity of 977 fb collected with the
Belle detector at the KEKB asymmetric-energy collider. No CP violation
has been observed and the CP asymmetry in decay is
measured to be , which is the most sensitive
measurement to date. After subtracting CP violation due to
mixing, the CP asymmetry in decay is found to be
.Comment: 15 pages, 4 figures, 1 table. Published in JHE
Measurements of Branching Fractions and Time-dependent CP Violating Asymmetries in Decays
We report measurements of branching fractions and time-dependent CP
asymmetries in and decays
using a data sample that contains pairs
collected at the resonance with the Belle detector at the KEKB
asymmetric-energy collider. We determine the branching fractions to
be
and . We measure CP asymmetry parameters and in and , ,
, and in , where the first uncertainty is
statistical and the second is systematic. We exclude the conservation of CP
symmetry in both decays at equal to or greater than significance.Comment: 7 pages, 2 figure
Evidence for the Suppressed Decay B- -> DK-, D -> K+pi-
The suppressed decay chain B- -> DK-, D -> K+pi-, where D indicates a anti-D0
or D0 state, provides important information on the CP-violating angle phi_3. We
measure the ratio R_{DK} of the decay rates to the favored mode B- -> DK-, D ->
K-pi+ to be R_{DK} = [1.63^{+0.44}_{-0.41}(stat)^{+0.07}_{-0.13}(syst)] x
10^{-2}, which indicates the first evidence of the signal with a significance
of 4.1sigma. We also measure the asymmetry A_{DK} between the charge-conjugate
decays to be A_{DK} = -0.39^{+0.26}_{-0.28}(stat)^{+0.04}_{-0.03}(syst). The
results are based on the full 772 x 10^6 B anti-B pair data sample collected at
the Upsilon(4S) resonance with the Belle detector.Comment: 6 pages, 2 figures, 2 tables, accepted by Physical Review Letter
Measurement of the CP Violation Parameters in B0 -> pi+ pi- Decays
We present a measurement of the time-dependent charge-parity (CP) violation
parameters in B0 -> pi+ pi- decays. The results are obtained from the final
data sample containing 772 million BBbar pairs collected at the Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider.
We obtain the CP violation parameters Acp = +0.33 +/- 0.06 (stat) +/- 0.03
(syst) and Scp = -0.64 +/- 0.08 (stat) +/- 0.03 (syst), where Acp and Scp
represent the direct and mixing-induced CP asymmetry, respectively. Using an
isospin analysis including results from other Belle measurements, we find 23.8
< phi2 < 66.8 degrees is disfavored at the 1 sigma level, where phi2 is one of
the three interior angles of the CKM unitarity triangle related to B_{u,d}
decays.Comment: 16 pages, 5 figures, CKM2012 conference paper, Submitted to PR
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