Geometric, Variational Integrators for Computer Animation

We present a general-purpose numerical scheme for time integration of Lagrangian dynamical systems—an important computational tool at the core of most physics-based animation techniques. Several features make this particular time integrator highly desirable for computer animation: it numerically preserves important invariants, such as linear and angular momenta; the symplectic nature of the integrator also guarantees a correct energy behavior, even when dissipation and external forces are added; holonomic constraints can also be enforced quite simply; finally, our simple methodology allows for the design of high-order accurate schemes if needed. Two key properties set the method apart from earlier approaches. First, the nonlinear equations that must be solved during an update step are replaced by a minimization of a novel functional, speeding up time stepping by more than a factor of two in practice. Second, the formulation introduces additional variables that provide key flexibility in the implementation of the method. These properties are achieved using a discrete form of a general variational principle called the Pontryagin-Hamilton principle, expressing time integration in a geometric manner. We demonstrate the applicability of our integrators to the simulation of non-linear elasticity with implementation details

Analyse du canal Bs-> Jpsi K*bar et contraintes sur les processus pingouins dans les désintégrations Bs->Jpsi Phi auprès du détecteur LHCb

Within the Standard Model, the decay Bs->Jpsi Phi can occur via two main processes: the predominant tree and the sub-leading penguin. Penguin contributions have been so far ignored. Controlling them is crucial in order to disentangle Standard Model effects from possible New Physics in the measurement of \phis. We studied the Bs->Jpsi K*bar channel where penguin diagrams are not negligible compared to tree. Using 3 fb^{-1} of data collected by LHCb, we measured the branching ratio: \BR{Bs-> Jpsi K*bar} = \left(4.17 \pm 0.18 \, \text{(stat)} \pm 0.26 \, \text{(syst)} \pm 0.24 \, (f_d/f_s)\right)\times 10^{-5},\\where $f_{d(s)}$ is the production fraction of the Bd(Bs) meson. We performed an angular analysis of the decay products Jpsi and K*bar to extract thepolarisation fractions and the first estimate of the polarization-dependent direct \CP asymmetry. Our results show no evidence for direct \CP violation in Bs->Jpsi K*bar, as expected in the Standard Model. We measured: $f_0 =0.497^{+0.024}_{-0.025}\text{(stat)}\pm 0.025 \text{(syst)}$ and $f_\|=0.179^{+0.027}_{-0.026} \text{(stat)}\pm 0.013 \text{(syst)}$. We determined the first constraints on penguin diagrams in \phis phase using the Bs->Jpsi K*bar channel. Combining with the Bd->Jpsi rho^0 decays, the shift on \phis, due to penguin processes, is below 19\,mrad for the three polarizations. The effect of penguin processes is therefore sufficiently small to keep the \phis measurement (\sigma_{\phis}=35\,mrad) among the top priorities of LHCb for the upcoming years, to search for New Physics.La désintégration Bs->Jpsi Phi peut se faire suivant deux processus principaux: l'arbre et les pingouins sous-dominants.Négligée jusqu'à maintenant, la contribution des diagrammes pingouins doit être contrôlée afin d'isoler les effets du Modèle Standard de l'éventuelle présence de Nouvelle Physique dans la mesure de la phase \phis. Nous avons étudié le canal Bs->Jpsi K*bar dans lequel les diagrammes pingouins ne sont pas négligeables par rapport à l'arbre. Avec 3 fb^{-1} de données enregistrées par LHCb, nous avons mesuré le rapport d'embranchement: \BR{Bs-> Jpsi K*bar} = \left(4.17 \pm 0.18 \, \text{(stat)} \pm 0.26 \, \text{(syst)} \pm 0.24 \, (f_d/f_s)\right)\times 10^{-5},o\`u $f_{d(s)}$ est la fraction de production du méson Bd(Bs). Nous avons effectué une analyse angulaire des produits de désintégrations Jpsi et K*bar afin d'extraire les fractions de polarisations et, pour la première fois, l'asymétrie \CP en fonction des différents états de polarisations de l'état final. Les asymétries \CP directes mesurées sont nulles, comme prédit par le Modèle Standard. Nous avons mesuré: $f_0 =0.497^{+0.024}_{-0.025}\text{(stat)}\pm 0.025 \text{(syst)}$ et $f_\|=0.179^{+0.027}_{-0.026} \text{(stat)}\pm 0.013 \text{(syst)}$. Nous avons déterminé les premières contraintes sur les diagrammes pingouins dans la phase \phis en utilisant le canal Bs->Jpsi K*bar. En combinant avec le canal Bd->Jpsi rho^0, la déviation sur la phase \phis due aux processus pingouins, est inférieure à 19\,mrad pour les trois polarisations. L'effet des processus pingouins est donc suffisamment petit pour que la mesure de la phase \phis (\sigma_{\phis}=35\,mrad) demeure une des mesures phares de LHCb dans les années à venir, pour rechercher de la Nouvelle Physique

English in product advertisements in non-english speaking countries in western europe: Product image and comprehension of the text

Although English has been shown to be the most frequently used foreign language in product advertisements in countries where it is not the native language, little is known about its effects. This article examines the response to advertisements in English compared to the response to the same ad in the local language in Western Europe on members of the target group for which the ad was intended: 715 young, highly educated female consumers. The use of English in a product ad does not appear to have any impact on image and price of the product, but it does affect text comprehension: the meaning of almost 40% of the English phrases was not understood. These results were the same for all countries involved in the study, irrespective of whether the respondents\u27 (self-) reported proficiency in English is high or low. © Taylor & Francis Group, LLC

Desulfotomaculum varum sp. nov., a moderately thermophilic sulfate-reducing bacterium isolated from a microbial mat colonizing a Great Artesian Basin bore well runoff channel

A strictly anaerobic moderately thermophilic bacterium, designated strain RH04-3T (T = type strain), was isolated from a red colored microbial mat that colonizes a Great Artesian Basin (GAB) bore well (Registered Number 17263) runoff channel at 66 °C. The cells of strain RH04-3T were straight to slightly curved, sporulating, Gram-positive rods (2.0–5.0 × 1.0 μm) that grew optimally at 50 °C (temperature growth range between 37 and 55 °C) and at pH 7 (pH growth range of 5.0 and 8.5). Growth was inhibited by NaCl concentrations ≥1.5% (w/v), and by chloramphenicol, streptomycin, tetracycline, penicillin and ampicillin. The strain utilized fructose, mannose, glycerol, lactate, pyruvate and H2 in the presence of sulfate, and fermented pyruvate in the absence of sulfate. Strain RH04-3T reduced sulfate, sulfite, thiosulfate and elemental sulfur, but not nitrate, nitrite, iron(III), arsenate(V), vanadium(V) or cobalt(III) as terminal electron acceptors. The G + C content of DNA was 52.4 ± 0.8 mol % as determined by the thermal denaturation (Tm) method. 16S rRNA sequence analysis indicated that strain RH04-3T was a member of the genus Desulfotomaculum and was most closely related to Desulfotomaculum putei (similarity value of 95.2%) and Desulfotomaculum hydrothermale (similarity value of 93.6%). On the basis of phylogenetic and phenotypic characteristics, strain RH04-3T is considered to represent a novel species of the genus Desulfotomaculum, for which the name Desulfotomaculum varum sp. nov. is proposed. The type strain RH04-3T = JCM 16158T = KCTC 5794T

Observation of two new Ξb−\Xi_b^- baryon resonances

Two structures are observed close to the kinematic threshold in the $\Xi_b^0 \pi^-$ mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb$^{-1}$ recorded by the LHCb experiment. In the quark model, two baryonic resonances with quark content $bds$ are expected in this mass region: the spin-parity $J^P = \frac{1}{2}^+$ and $J^P=\frac{3}{2}^+$ states, denoted $\Xi_b^{\prime -}$ and $\Xi_b^{*-}$. Interpreting the structures as these resonances, we measure the mass differences and the width of the heavier state to be $m(\Xi_b^{\prime -}) - m(\Xi_b^0) - m(\pi^{-}) = 3.653 \pm 0.018 \pm 0.006$ MeV$/c^2$, $m(\Xi_b^{*-}) - m(\Xi_b^0) - m(\pi^{-}) = 23.96 \pm 0.12 \pm 0.06$ MeV$/c^2$, $\Gamma(\Xi_b^{*-}) = 1.65 \pm 0.31 \pm 0.10$ MeV, where the first and second uncertainties are statistical and systematic, respectively. The width of the lighter state is consistent with zero, and we place an upper limit of $\Gamma(\Xi_b^{\prime -}) < 0.08$ MeV at 95% confidence level. Relative production rates of these states are also reported.Comment: 17 pages, 2 figure

Observation of associated production of a ZZ boson with a DD meson in the~forward region

A search for associated production of a $Z$ boson with an open charm meson is presented using a data sample, corresponding to an integrated luminosity of $1.0\,\mathrm{fb}^{-`}$ of proton--proton collisions at a centre-of-mass energy of 7\,TeV, collected by the LHCb experiment. %% Seven candidate events for associated production of a $Z$ boson with a $D^0$ meson and four candidate events for a $Z$ boson with a $D^+$ meson are observed with a combined significance of 5.1standard deviations. The production cross-sections in the forward region are measured to be $$\sigma_{Z\rightarrow\mu^+\mu^-\!,D^0} = 2.50\pm1.12\pm0.22pb$$ $$\sigma_{Z\rightarrow\mu^+\mu^-\!,D^+} = 0.44\pm0.23\pm0.03pb,$$ where the first uncertainty is statistical and the second systematic.Comment: 18 pages, 2 figure

Measurements of the B+B^+, B0B^0, Bs0B_s^0 meson and Λb0\Lambda_b^0 baryon lifetimes

Measurements of $b$-hadron lifetimes are reported using $pp$ collision data, corresponding to an integrated luminosity of 1.0fb$^{-1}$, collected by the LHCb detector at a centre-of-mass energy of $7$Tev. Using the exclusive decays $B^+\to J/\psi K^+$, $B^0\to J/\psi K^*(892)^0$, $B^0\to J/\psi K^0_{\rm S}$, $\Lambda_b^0\to J/\psi \Lambda$ and $B^0_s\to J/\psi \phi$ the average decay times in these modes are measured to be $\tau_{B^+\to J/\psi K^+}$ = $1.637 \pm$ 0.004 $\pm$ 0.003 ps, $\tau_{B^0\to J/\psi K^*(892)^0}$ = $1.524 \pm$ 0.006 $\pm$ 0.004 ps, $\tau_{B^0\to J/\psi K^0_{\rm S}}$ = $1.499 \pm$ 0.013 $\pm$ 0.005 ps, $\tau_{\Lambda_b^0\to J/\psi \Lambda}$ = $1.415 \pm$ 0.027 $\pm$ 0.006 ps and $\tau_{B^0_s\to J/\psi \phi}$ = $1.480 \pm$ 0.011 $\pm$ 0.005 ps, where the first uncertainty is statistical and the second is systematic. These represent the most precise lifetime measurements in these decay modes. In addition, ratios of these lifetimes, and the ratio of the decay-width difference, $\Delta\Gamma_d$, to the average width, $\Gamma_d$, in the $B^0$ system, $\Delta \Gamma_d/\Gamma_d = -0.044 \pm 0.025 \pm 0.011$, are reported. All quantities are found to be consistent with Standard Model expectations.Comment: 28 pages, 4 figures. Updated reference

Evidence for the strangeness-changing weak decay Ξb−→Λb0π−\Xi_b^-\to\Lambda_b^0\pi^-

Using a $pp$ collision data sample corresponding to an integrated luminosity of 3.0~fb$^{-1}$, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay $\Xi_b^-\to\Lambda_b^0\pi^-$. No $b$ hadron decay of this type has been seen before. A signal for this decay, corresponding to a significance of 3.2 standard deviations, is reported. The relative rate is measured to be ${{f_{\Xi_b^-}}\over{f_{\Lambda_b^0}}}{\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) = (5.7\pm1.8^{+0.8}_{-0.9})\times10^{-4}$, where $f_{\Xi_b^-}$ and $f_{\Lambda_b^0}$ are the $b\to\Xi_b^-$ and $b\to\Lambda_b^0$ fragmentation fractions, and ${\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-)$ is the branching fraction. Assuming $f_{\Xi_b^-}/f_{\Lambda_b^0}$ is bounded between 0.1 and 0.3, the branching fraction ${\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-)$ would lie in the range from $(0.57\pm0.21)\%$ to $(0.19\pm0.07)\%$.Comment: 7 pages, 2 figures, All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-047.htm

Measurement of the mass and lifetime of the Ωb−\Omega_b^- baryon

A proton-proton collision data sample, corresponding to an integrated luminosity of 3 fb$^{-1}$ collected by LHCb at $\sqrt{s}=7$ and 8 TeV, is used to reconstruct $63\pm9$ $\Omega_b^-\to\Omega_c^0\pi^-$, $\Omega_c^0\to pK^-K^-\pi^+$ decays. Using the $\Xi_b^-\to\Xi_c^0\pi^-$, $\Xi_c^0\to pK^-K^-\pi^+$ decay mode for calibration, the lifetime ratio and absolute lifetime of the $\Omega_b^-$ baryon are measured to be \begin{align*} \frac{\tau_{\Omega_b^-}}{\tau_{\Xi_b^-}} &= 1.11\pm0.16\pm0.03, \\ \tau_{\Omega_b^-} &= 1.78\pm0.26\pm0.05\pm0.06~{\rm ps}, \end{align*} where the uncertainties are statistical, systematic and from the calibration mode (for $\tau_{\Omega_b^-}$ only). A measurement is also made of the mass difference, $m_{\Omega_b^-}-m_{\Xi_b^-}$, and the corresponding $\Omega_b^-$ mass, which yields \begin{align*} m_{\Omega_b^-}-m_{\Xi_b^-} &= 247.4\pm3.2\pm0.5~{\rm MeV}/c^2, \\ m_{\Omega_b^-} &= 6045.1\pm3.2\pm 0.5\pm0.6~{\rm MeV}/c^2. \end{align*} These results are consistent with previous measurements.Comment: 11 pages, 5 figures, All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-008.htm

Observation of the decay Bc→J/ψK+K−π+B_c \rightarrow J/\psi K^+ K^- \pi^+

The decay $B_c\rightarrow J/\psi K^+ K^- \pi^+$ is observed for the first time, using proton-proton collisions collected with the LHCb detector corresponding to an integrated luminosity of 3fb$^{-1}$. A signal yield of $78\pm14$ decays is reported with a significance of 6.2 standard deviations. The ratio of the branching fraction of \B_c \rightarrow J/\psi K^+ K^- \pi^+ decays to that of $B_c \rightarrow J/\psi \pi^+$ decays is measured to be $0.53\pm 0.10\pm0.05$, where the first uncertainty is statistical and the second is systematic.Comment: 18 pages, 2 figure