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[en] Phosphorus-containing dendrimers are defined as dendrimers having at least one phosphorus atom at each branching point. In this review, we will show how phosphorhydrazone dendrimers can be modified at will at the level of the core and of the branches, to afford specific properties, such as fluorescence to image biological events. Accelerated methods of synthesis of phosphorus (one step for one generation) will be also displayed, as well as the specific reactivity of P=N–P=S linkages obtained in most of these accelerated method of synthesis, which has led to particularly original dendritic architectures, such as dendrons included in dendrimers. Finally, we will display how modifications of the internal structure of a series of dendrimers having the same type and number of terminal functions can deeply modify their biological anti-inflammatory properties. Among the six critical nanoscale design parameters (CNDP), we will show how two of them, i.e., architecture and elemental composition, have been particularly engineered to modify phosphorus-containing dendrimers, in order to fulfill the desired properties.
[en] The authors report a new measurement of the decay (Omega)- → Ξ- π+π- with 76 events and a first observation of the decay (bar (Omega))+ → (bar Ξ)+ π+π- with 24 events, yielding a combined branching ratio (3.74-0.56+0.67) x 10-4. This represents a factor 25 increase in statistics over the best previous measurement. No evidence is seen for CP violation, with Β((Omega)- → Ξ- π+π-) = 4.04-0.71+0.83 x 10-4 and Β((bar (Omega))+ → (bar Ξ)+ π+π-) = 3.15-0.89+1.12 x 10-4. Contrary to theoretical expectation, they see little evidence for the decays (Omega)- → Ξ*15300 π- and (bar (Omega))+ → (bar Ξ)*15300 π+ and place a 90% C.L. upper limit on the combined branching ratio Β((Omega)-((bar (Omega))+) → Ξ*15300 ((bar Ξ)*15300)π#-+#) < 7.0 x 10-5.
[en] We discuss the N A 62 experiment which aims at the search for phenomena beyond the Standard Model (S M) by measuring the ratio RK = Γ(K± → e±ν(γ))/Γ(K± → μ±ν(γ)) and the ultra rare decay K+ → π+ νν. First, we summarize the status of the RK analysis, based on ∼ 40 % of the 2007-2008 N A 62 data set, then, we describe the N A 62 proposal to measure the branching ratio of the very rare decay K+ → π+ νν and we give an update on the status of the detectors needed to perform the measurement.
[en] A laser beam introduced into a simple soap film unexpectedly breaks out into thin (micron-thick) branching channels which keep unspread (without divergence) sometimes for as long as tens of centimeters as they go along the film. The physical interpretation and possible applications of the phenomenon are discussed in this paper. (methodological notes)
[en] The MEG collaboration searches for the μ → eγ decay at the muon beam line πE5 of the Paul Scherrer Institut in Switzerland. The world best upper limit has been set to be B(μ → eγ) < 5.7 10-13 at 90 % C.L. analyzing a data set of 3.6 1014 stopped muons on target. An upgrade program of the detector (MEG-II) should lead to a sensitivity at a level of few 10-14 within the next 5 years. (author)
[en] Splint of root system of simple Lie algebra appears naturally in the study of (regular) embeddings of reductive subalgebras. It can be used to derive branching rules. Application of splint properties drastically simplifies calculations of branching coefficients. We study affine extension of splint root system of simple Lie algebra and obtain relations on theta and branching functions.
[en] Separate measurements of the Bu and Bd semileptonic branching fractions have been made using 1.4 fb-1 of data taken with the CLEO-II detector at the Υ(4S) resonance. A new technique is utilized in which a bar B meson is exclusively reconstructed in order to tag the charge and flavor. Approximately 2000 fully reconstructed candidates are found in the data sample. Since the Υ(4S) decays to B bar B, the tracks from the B meson can then be examined for lepton content. The efficiency corrected ratio of the number of leptons and the number of tags determines the semileptonic branching fractions. This method allows for the first separate measurement of the charged B meson semileptonic branching ratio in contrast to other techniques which measure the flavor averaged branching fractions. Assuming that the partial semileptonic decay widths of the charged and neutral B's are equal, the lifetime ratio can be measured from the ratio of semileptonic branching fractions. Since the flavor is explicitly tagged, no assumptions concerning the product fractions of the Bu and Bd (f+- and f00) are used, unlike results of past Υ(4S) experiments. Hence, with the exception of the partial semileptonic width equality, the only assumption used is that of the shape of the direct lepton (B → ell X) momentum spectrum in efficiency determination. Theoretical dependence is thus kept at a minimum. The measured results for the branching fractions and lifetime ratio are: B(B+ → X ell +ν) = (13.0 ± 1.8 ± 1.6)%; B(B0 → X ell +ν) = (14.5 ± 2.1 ± 1.9)%; τ(B0)/τ(B+) = 0.90 ± 0.18 ± 0.12