Search results for "Branching"
showing 10 items of 918 documents
Search for excited electrons and muons in root s=8 TeV proton-proton collisions with the ATLAS detector
2013
The ATLAS detector at the Large Hadron Collider is used to search for excited electrons and excited muons in the channel pp → ℓℓ* → ℓℓγ, assuming that excited leptons are produced via contact interactions. The analysis is based on 13 fb[superscript −1] of pp collisions at a centre-of-mass energy of 8 TeV. No evidence for excited leptons is found, and a limit is set at the 95% credibility level on the cross section times branching ratio as a function of the excited-lepton mass m[subscript ℓ*]. For m[subscript ℓ*] ≥ 0.8 TeV, the respective upper limits on σB(ℓ* → ℓγ) are 0.75 and 0.90 fb for the e* and μ* searches. Limits on σB are converted into lower bounds on the compositeness scale Λ. In …
Differential branching fractions and isospin asymmetries of B -> K ((*)) μ(+) μ(-) decays
2014
The isospin asymmetries of $B \to K\mu^+\mu^-$ and $B \to K^{*}\mu^+\mu^-$ decays and the partial branching fractions of the $B^0 \to K^0\mu^+\mu^-$, $B^+ \to K^+\mu^+\mu^-$ and $B^+ \to K^{*+}\mu^+\mu^-$ decays are measured as functions of the dimuon mass squared, $q^2$. The data used correspond to an integrated luminosity of 3$~$fb$^{-1}$ from proton-proton collisions collected with the LHCb detector at centre-of-mass energies of 7$\,$TeV and 8$\,$TeV in 2011 and 2012, respectively. The isospin asymmetries are both consistent with the Standard Model expectations. The three measured branching fractions, while individually consistent, all favour lower values than their respective Standard M…
Search for Baryonic Decays of \psi(3770) and \psi(4040)
2013
By analyzing data samples of 2.9 fb^{-1} collected at \sqrt s=3.773 GeV, 482 pb^{-1} collected at \sqrt s=4.009 GeV and 67 pb^{-1} collected at \sqrt s=3.542, 3.554, 3.561, 3.600 and 3.650 GeV with the BESIII detector at the BEPCII storage ring, we search for \psi(3770) and \psi(4040) decay to baryonic final states, including \Lambda\bar\Lambda\pi^+\pi^-, \Lambda \bar\Lambda\pi^0, \Lambda\bar\Lambda\eta, \Sigma^+ \bar\Sigma^-, \Sigma^0 \bar\Sigma^0, \Xi^-\bar\Xi^+ and \Xi^0\bar\Xi^0 decays. None are observed, and upper limits are set at the 90% confidence level.
Observation of Two NewN*Resonances in the Decayψ(3686)→pp¯π0
2013
Based on 106 x 10(6)psi(3686) events collected with the BESIII detector at the BEPCII facility, a partial wave analysis of psi(3686) -> p (p) over bar pi(0) is performed. The branching fraction of this channel has been determined to be B psi(3686) -> p (p) over bar pi(0) = (1.65 +/- 0.03 +/- 0.15) x 10(-4). In this decay, 7 N* intermediate resonances are observed. Among these, two new resonances, N(2300) and N(2570) are significant, one 1/2(+) resonance with a mass of 2300(-30-0)(+40+109) MeV/c(2) and width of 340(-30-58)(+30+110) MeV/c(2), and one 5/2(-) resonance with a mass of 2570(-10-10)(+19+34) MeV/c(2) and width of 250(-24-21)(+14+69) MeV/c(.)(2) For the remaining 5 N* intermediate r…
Study of J/ψ and ψ(3686)→Σ(1385)0Σ¯(1385)0 and Ξ0Ξ¯0
2017
Abstract We study the decays of J / ψ and ψ ( 3686 ) to the final states Σ ( 1385 ) 0 Σ ¯ ( 1385 ) 0 and Ξ 0 Ξ ¯ 0 based on a single baryon tag method using data samples of ( 1310.6 ± 7.0 ) × 10 6 J / ψ and ( 447.9 ± 2.9 ) × 10 6 ψ ( 3686 ) events collected with the BESIII detector at the BEPCII collider. The decays to Σ ( 1385 ) 0 Σ ¯ ( 1385 ) 0 are observed for the first time. The measured branching fractions of J / ψ and ψ ( 3686 ) to Ξ 0 Ξ ¯ 0 are in good agreement with, and much more precise than, the previously published results. The angular parameters for these decays are also measured for the first time. The measured angular decay parameter for J / ψ → Σ ( 1385 ) 0 Σ ¯ ( 1385 ) 0 , …
Measurements of baryon pair decays of chi(cJ) mesons
2013
Using 106 $\times 10^{6}$ $\psi^{\prime}$ decays collected with the BESIII detector at the BEPCII, three decays of $\chi_{cJ}$ ($J=0,1,2$) with baryon pairs ($\llb$, $\ssb$, $\SSB$) in the final state have been studied. The branching fractions are measured to be $\cal{B}$$(\chi_{c0,1,2}\rightarrow\Lambda\bar\Lambda) =(33.3 \pm 2.0 \pm 2.6)\times 10^{-5}$, $(12.2 \pm 1.1 \pm 1.1)\times 10^{-5}$, $(20.8 \pm 1.6 \pm 2.3)\times 10^{-5}$; $\cal{B}$$(\chi_{c0,1,2}\rightarrow\Sigma^{0}\bar\Sigma^{0})$ = $(47.8 \pm 3.4 \pm 3.9)\times 10^{-5}$, $(3.8 \pm 1.0 \pm 0.5)\times 10^{-5}$, $(4.0 \pm 1.1 \pm 0.5) \times 10^{-5}$; and $\cal{B}$$(\chi_{c0,1,2}\rightarrow\Sigma^{+}\bar\Sigma^{-})$ = $(45.4 \pm…
Measurement of the production fraction times branching fractionf(b→Λb)·B(Λb→J/ψΛ)
2011
The \Lambda_b(udb) baryon is observed in the decay \Lambda_b --> J/\psi \Lambda using 6.1 fb^{-1} of p\bar{p} collisions collected with the D0 detector at \sqrt{s}=1.96 TeV. The production fraction multiplied by the branching fraction for this decay relative to that for the decay B^0 --> J/\psi K^0_s is measured to be 0.345 \pm 0.034 (stat.) \pm 0.033 (syst.) \pm 0.003 (PDG). Using the world average value of f(b --> B^0)B(B^0 --> J/\psi K^0_s) = (1.74 \pm 0.08) \times 10^{-5}, we obtain f(b --> \Lambda_b)B(\Lambda_{b} --> J/\psi \Lambda) = (6.01 \pm 0.60 (stat.) \pm 0.58 (syst.) \pm 0.28 (PDG)) \times 10^{-5}. This measurement represents an improvement in precision by about a factor of thre…
Polymer Incompatibility Caused by Different Molecular Architectures: Modeling via Chain Connectivity and Conformational Relaxation
2009
The calculation of phase diagrams for blends of linear and branched polymers made up of identical monomeric units is modeled using an approach that subdivides the mixing process into two steps: i) contact formation between the different components, keeping their chain conformations and the volume of the system constant; and, ii) relaxation of the macromolecules into their equilibrium state by molecular rearrangements. It is assumed that step (ii) causes shape-induced polymer incompatibility and that the degree of branching can be quantified in terms of the volumes the isolated coils of the branched polymer occupy in relation to the volume the linear product with the same molecular weight oc…
Characterization of melt-polymerized polycarbonate: preparative fractionation, branching distribution and simulation
2001
Melt-polymerized bisphenol-A polycarbonate materials characterized by a low degree of branching were fractionated according to molecular weight by the continuous polymer fractionation (CPF) method. The distribution of two types of end-groups and in-chain salicylate moieties arising from thermal rearrangement reactions were assessed across the molecular weight distribution by analysis of the fractions. Experimentally determined branching densities of the fractions agreed well with a molecular simulation based on a random sampling polycondensation model. Both simulation and experiments showed that the branching density increases with molecular weight in the experimentally accessible range. (C…
Zum Ursprung der Hominidae
1981
A fundamental problem of hominisation is the branching of the human lineage leading to the genusHomo from other hominoids. At present discussed hypotheses of a Miocene separation of the pongid and hominid lineage are described under consideration of numerous new fossils from Europe, Asia and Africa. Of special interest is the possibility of an adhominisation of the genusAustralopithecus (includingA. afarensis).