Search results for "quantity"
showing 10 items of 151 documents
Precision measurements of proton emission from the ground states ofTa156andRe160
2011
The decays of the $\ensuremath{\pi}{d}_{3/2}$ ground states of $^{156}\mathrm{Ta}$ and $^{160}\mathrm{Re}$ have been studied in detail using the GREAT spectrometer. More than 7000 $^{160}\mathrm{Re}$ nuclei were produced in reactions of 290- and 300-MeV $^{58}\mathrm{Ni}$ ions with an isotopically enriched $^{106}\mathrm{Cd}$ target and separated in flight using the RITU separator. The proton and $\ensuremath{\alpha}$ decays of the $\ensuremath{\pi}{d}_{3/2}$ level were confirmed and the half-life and branching ratios of this state were determined with improved precision to be ${t}_{1/2}=611\ifmmode\pm\else\textpm\fi{}7$ $\ensuremath{\mu}$s and ${b}_{\mathrm{p}}=89\ifmmode\pm\else\textpm\fi…
Duality relation between radiation thermodynamics and cosmic string loop thermodynamics
2011
We discuss thermodynamics of electromagnetic radiation, with p=(1/3){rho} and S{proportional_to}T{sup 3}V, and of cosmic string loops, with p=-(1/3){rho} and S{proportional_to}T{sup -3}V, where p stands for pressure, T temperature, {rho} energy density, S entropy, and V volume. We write the thermodynamic formalisms under a common framework that illustrates their formal relationship and allows us to go from one to the other through a smooth transformation. From a microscopic perspective, these relations arise from the energy relations u({lambda})=hc/{lambda} for the photons of electromagnetic radiation, and u(l)=(c{sup 4}/a{sup 2}G)l for cosmic string loops, a being a numerical (dimensionles…
Measurement oftt¯production in theτ+jetstopology usingpp¯collisions ats=1.96 TeV
2010
We present a measurement of the t (t) over bar production cross section multiplied by the branching ratio to tau lepton decaying semihadronically (tau(h)) plus jets, sigma(p (p) over bar -> t (t) over bar + X) center dot BR(t (t) over bar -> tau(h) + jets), at a center of mass energy root s = 1.96 TeV using 1 fb(-1) of integrated luminosity collected with the D0 detector. Assuming a top quark mass of 170 GeV, we measure sigma(t (t) over bar) center dot BR tau h (+ j) = 0.60(-0.22)(+0.23)(stat)(-0.14)(+0.15)(syst) +/- 0.04(lumi) pb. In addition, we extract the t (t) over bar production cross section using the t (t) over bar -> tau(h) + jets topology, with the result sigma(t (t) over bar) = 6…
New measurement of the K±→π±μ+μ− decay
2011
Abstract A sample of 3120 K ± → π ± μ + μ − decay candidates with ( 3.3 ± 0.7 ) % background contamination has been collected by the NA48/2 experiment at the CERN SPS, allowing a detailed study of the decay properties. The branching ratio was measured to be BR = ( 9.62 ± 0.25 ) × 10 − 8 . The form factor W ( z ) , where z = ( M μ μ / M K ) 2 , was parameterized according to several models. In particular, the slope of the linear form factor W ( z ) = W 0 ( 1 + δ z ) was measured to be δ = 3.11 ± 0.57 . Upper limits of 2.9 × 10 − 2 and 2.3 × 10 − 2 on possible charge asymmetry and forward–backward asymmetry were established at 90% CL. An upper limit BR ( K ± → π ∓ μ ± μ ± ) 1.1 × 10 − 9 was e…
Measurement of the 151Sm n,gamma 152Sm cross section at n_TOF
2005
The 151 Sm(n, γ ) 152 Sm cross section, which is important for the interpretation of the 151 Sm branching as an s -process thermometer, was measured from 1 eV up to 1 MeV at the innovative n_TOF facility at CERN. Based on these data, the Maxwellian-averaged cross section at k T = 30 keV is found to be 3100±160 mb. This value can be used to constrain the thermodynamical conditions in Asymptotic Giant Branch (AGB) stars during He-shell burning.
Structure of theN=27isotones derived from theAr44(d,p)Ar45reaction
2008
The $^{44}\mathrm{Ar}$($d,p$)$^{45}\mathrm{Ar}$ neutron transfer reaction was performed at $10A$ MeV. Measured excitation energies, deduced angular momenta, and spectroscopic factors of the states populated in $^{45}\mathrm{Ar}$ are reported. A satisfactory description of these properties is achieved in the shell model framework using a new $\mathit{sdpf}$ interaction. The model analysis is extended to more exotic even-$Z$ nuclei down to ${}_{14}^{41}{\mathrm{Si}}_{27}$ to study how collectivity impacts the low-lying structure of $N=27$ neutron-rich nuclei.
Deep sub-threshold K*(892)0 production in collisions of Ar + KCl at 1.76A GeV
2013
Results on the deep sub-threshold production of the short-lived hadronic resonance K*(892)0 are reported for collisions of Ar + KCl at 1.76A GeV beam energy, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. The K*(892)0 production probability per central collision of \( P_{K^{*0}}=(4.4\pm 1.1 \pm 0.5)\times 10^{-4}\) and the K*(892)0/K0 ratio of \( P_{K^{*0}}/P_{K^0}=(1.9\pm 0.5\pm 0.3)\times 10^{-2}\) are determined at the lowest energy so far (i.e. deep below the threshold for the corresponding production in nucleon-nucleon collisions, \( \sqrt{s_{NN}}-\sqrt{s_{thr}}=-340\) MeV). The K*0/K0 ratio is compared with results of other experiments and with the pre…
High-Kfour-quasiparticle states inGd138
2011
States above the known ${K}^{\ensuremath{\pi}}={8}^{\ensuremath{-}}$ 6 $\ensuremath{\mu}$s isomer in $^{138}\mathrm{Gd}$ have been populated with the $^{106}\mathrm{Cd}$($^{36}\mathrm{Ar}$,$2p2n$) reaction at a beam energy of 180 MeV at the University of Jyv\"askyl\"a, Finland. The recoil-isomer tagging technique was utilized to correlate delayed $\ensuremath{\gamma}$-ray decays, detected in the GREAT focal plane spectrometer, with prompt decays measured in the JUROGAM II spectrometer at the target position. The lifetime of the ${K}^{\ensuremath{\pi}}={8}^{\ensuremath{-}}$ isomeric state has been remeasured as 6.2(2) $\ensuremath{\mu}$s. Two high-lying strongly coupled bands have been estab…
Dalitz plot analyses of J/ψ→π+π−π0 , J/ψ→K+K−π0 , and J/ψ→Ks0K±π∓ produced via e+e− annihilation with initial-state radiation
2017
We study the processes e^+e^− → γISR J/ψ, where J/ψ → π^+π^−π^0, J/ψ → K^+K^−π^0, and J/ψ → K^0_SK^±π^∓ using a data sample of 519 fb^(−1) recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e^+e^− collider at center-of-mass energies at and near the Υ(nS) (n=2,3,4) resonances. We measure the ratio of branching fractions R_1 = ^(B(J/ψ → K^+K^−π^0)) /_(B(J/ψ → π^+π^−π^0)) and R_2 = ^(B(J/ψ → K^0_SK^±π^∓))/_(B(J/ψ → π^+π^−π^0)). We perform Dalitz plot analyses of the three J/ψ decay modes and measure fractions for resonances contributing to the decays. We also analyze the J/ψ → π^+π^−π^0 decay using the Veneziano model. We observe structures compatible with the pres…
Measurement of|Vcb|and the Form-Factor Slope inB¯→Dℓ−ν¯ℓDecays in Events Tagged by a Fully ReconstructedBMeson
2010
We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-cb vertical bar and the form-factor slope rho(2) in (B) over bar -> Dl(-) (nu) over bar (l) decays based on 460 X 10(6) B (B) over bar events recorded at the Gamma(4S) resonance with the BABAR detector. (B) over bar -> Dl(-) (nu) over bar (l) decays are selected in events in which a hadronic decay of the second B meson is fully reconstructed. We measure B(B- -> D(0)l(-) (nu) over bar (l))/B(B- -> Xl(-) (nu) over bar (l)) = (0.255 +/- 0.009 +/- 0.009) and B((B) over bar (0) -> D(+)l(-) (nu) over bar (l))/B((B) over bar (0) -> Xl(-) (nu) over bar (l)) = (0.230 +/- 0.011 +/- 0.011), along with the different…