30,973 research outputs found
Recent Results in Bottomonium
No full textGreat strides have been made in the understanding of bound states of the bottom quark, b, and its antiquark, (b) over bar, since the discovery of the first Upsilon resonances in 1977. These bound states, known as bottomonium, have a rich spectrum whose masses and transition amplitudes shed valuable light on the strong interactions. We review some recent developments in bottomonium physics, including the discovery of the spin-singlet states eta(b) (1S, 2S) and h(b) (1P, 2P), the first D-wave states, one or more candidates for spin-triplet.XbJ(3P) excitations, and above-threshold states with strong transitions to states below threshold. We also present information about transitions, production, and signatures of new physics
Search for violation in decays and observation of the Cabibbo-suppressed decay
No full textWe search for violation by measuring a -odd asymmetry in the
Cabibbo-suppressed decay, and
in the Cabibbo-favored and
decays. We use 980 of data collected by the Belle detector running at the KEKB
asymmetric-energy collider. The -violating -odd parameter
is measured to be
and
where the first
uncertainty is statistical and the second is systematic. We also report the
first observation of the Cabibbo-suppressed decay . The branching fraction is measured relative to
that of the analogous Cabibbo-favored decay :
Letter from Franklin K. Lane, Secretary of the Interior, to Representative Hayden
No full textLetter from Franklin K. Lane to Carl T. Hayden expressing his support for bill S.390 in establishing the Grand Canyon as a National Park
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
DNA fusion gene vaccination mobilizes effective anti-leukemic cytotoxic T lymphocytes from a tolerized repertoire
No full textThe majority of known human tumor-associated antigens derive from non-mutated self proteins. T cell tolerance, essential to prevent autoimmunity, must therefore be cautiously circumvented to generate cytotoxic T cell responses against these targets. Our strategy uses DNA fusion vaccines to activate high levels of peptide-specific CTL. Key foreign sequences from tetanus toxin activate tolerance-breaking CD4+ T cell help. Candidate MHC class Ibinding tumor peptide sequences are fused to the C terminus for optimal processing and presentation. To model performance against a leukemia-associated antigen in a tolerized setting, we constructed a fusion vaccine encoding an immunodominant CTL epitopederived from Friend murine leukemia virus gag protein (FMuLVgag) and vaccinated tolerant FMuLVgag-transgenic (gag-Tg) mice. Vaccination with the construct induced epitopespecificIFN-c-producing CD8+ T cells in normal and gag-Tg mice. The frequency and avidity of activated cells were reduced in gag-Tg mice, and no autoimmune injury resulted. However, these CD8+ T cells did exhibit gag-specific cytotoxicity in vitro and in vivo. Also, epitope-specific CTL killed FBL-3 leukemia cells expressing endogenous FMuLVgag antigen and protected against leukemia challenge in vivo. These results demonstrate a simple strategy to engage anti-microbial T cell help to activate epitope-specific polyclonal CD8+ T cell responses from a residual tolerized repertoire
The K-T Extinction
No full textThis chapter from the book History of Life describes the results of the K-T extinction and looks at the Impact theory and a giant volcanic eruption as possible causes. The essay covers the catastrophic scenarios for extinction that could result from these events. After reviewing the paleontological record across the K-T boundary, the author concludes that it is not clear that the catastrophes themselves can explain the extinction patterns that we see in the fossil record. Educational levels: Graduate or professional, Undergraduate lower division, Undergraduate upper division
Measurement of the branching fractions for Cabibbo-suppressed decays D+→K+K−π+π0 and D(s)+→K+π−π+π0 at Belle
No full textWe present measurements of the branching fractions for the singly Cabibbo-suppressed decays D+→K+K−π+π0 and D+s→K+π−π+π0, and the doubly Cabibbo-suppressed decay D+→K+π−π+π0, based on 980 fb−1 of data recorded by the Belle experiment at the KEKB e+e− collider. We measure these modes relative to the Cabibbo-favored modes D+→K−π+π+π0 and D+s→K+K−π+π0. Our results for the ratios of branching fractions are B(D+→K+K−π+π0)/B(D+→K−π+π+π0)=(11.32±0.13±0.26)%, B(D+→K+π−π+π0)/B(D+→K−π+π+π0)=(1.68±0.11±0.03)%, and B(D+s→K+π−π+π0)/B(D+s→K+K−π+π0)=(17.13±0.62±0.51)%, where the uncertainties are statistical and systematic, respectively. The second value corresponds to (5.83±0.42)×tan4θC, where θC is the Cabibbo angle; this value is larger than other measured ratios of branching fractions for a doubly Cabibbo-suppressed charm decay to a Cabibbo-favored decay. Multiplying these results by world average values for B(D+→K−π+π+π0) and B(D+s→K+K−π+π0) yields B(D+→K+K−π+π0)=(7.08±0.08±0.16±0.20)×10^−3, B(D+→K+π−π+π0)=(1.05±0.07±0.02±0.03)×10^−3, and B(D+s→K+π−π+π0)=(9.44±0.34±0.28±0.32)×10^−3, where the third uncertainty is due to the branching fraction of the normalization mode. The first two results are consistent with, but more precise than, the current world averages. The last result is the first measurement of this branching fraction
Excitation and dissociation of 3-chloro-3-methyldiazirine and 1-pyrazoline by low-energy electron impact
No full textPT: J; CR: BATES DR, 1950, PHILOS T R SOC LON A, V243, P93 BRIDGE MR, 1969, J CHEM SOC A, P91 BUBERT H, 1971, J PHYS CHEM-US, V75, P769 CRAWFORD RJ, 1965, J AM CHEM SOC, V87, P3023 CRAWFORD RJ, 1966, J AM CHEM SOC, V88, P3959 DOERING JP, 1965, J CHEM PHYS, V42, P395 FINN TG, 1972, J CHEM PHYS, V56, P5632 FUKUI I, 1977, J PHYS CHEM, V81, P1252 FUKUI K, 1972, B CHEM SOC JPN, V45, P2278 FUKUI K, 1975, SHITSURYO BUNSEKI, V23, P105 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 HOLLAND RF, 1972, J CHEM PHYS, V56, P5229 KNOWLTON JW, 1949, J RES NBS, V43, P113 LAIDLER KJ, 1955, CHEM KINETICS EXCITE, P21 LAUFER A, 1972, J PHYS CHEM-US, V76, P3504 LIU MTH, 1974, CHEM ENG NEWS 0909, P3 MASSEY HSW, 1931, P R SOC LOND A-CONTA, V132, P605 OCHKUR VI, 1964, SOV PHYS JETP, V18, P503 OPPENHEIMER JR, 1928, PHYS REV, V32, P361 PENNEY WG, 1932, PHYS REV, V39, P467 ROSENSTOCK HM, 1977, J PHYS CHEM REF D S1, V6 VROOM DA, 1969, J CHEM PHYS, V50, P573; NR: 22; TC: 4; J9: J PHYS CHEM; PG: 4; GA: KS409Source type: Electronic(1
Local curvature-dimension condition implies measure-contraction property
No full textAbstractWe prove that for non-branching metric measure spaces the local curvature condition CDloc(K,N) implies the global version of MCP(K,N). The curvature condition CD(K,N) introduced by the second author and also studied by Lott and Villani is the generalization to metric measure space of lower bounds on Ricci curvature together with upper bounds on the dimension. This paper is the following step of Bacher and Sturm (2010) [1] where it is shown that CDloc(K,N) is equivalent to a global condition CD⁎(K,N), slightly weaker than the usual CD(K,N). It is worth pointing out that our result implies sharp Bishop–Gromov volume growth inequality and sharp Poincaré inequality
Angular analysis of the low K+K− invariant mass enhancement in B+→K+K−π+ decays
No full textWe study the decay B+→K+K−π+ and investigate the angular distribution of K+K− pairs with invariant mass below 1.1 GeV/c2. This region exhibits both a strong enhancement in signal and very large direct CP violation. We construct a coherent sum model for the angular distribution of S- and P-wave, and report the ratio of their amplitudes, the relative phase and the forward-backward asymmetry. We also report absolute differential branching fractions and direct CP asymmetry for the decay in bins of MK+K− and the differential branching fractions in bins of MK+π−. The results are based on a data sample that contains 772×10^6 BB ̄ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. The measured overall branching fraction and the direct CP asymmetry are (5.38±0.40±0.35)×10^−6 and −0.170±0.073±0.017, respectively, where the first uncertainties are statistical and the second are systematic
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