The production of \(J/\psi\) mesons in jets is studied in the forward region of proton-proton collisions using data collected with the LHCb detector at a center-of-mass energy of 13 TeV. The fraction ...of the jet transverse momentum carried by the \(J/\psi\) meson, \(z \equiv p_{\rm T}(J/\psi)/p_{\rm T}({\rm jet})\), is measured using jets with \(p_{\rm T}({\rm jet}) > 20\) GeV in the pseudorapidity range \(2.5 < \eta({\rm jet}) < 4.0\). The observed \(z\) distribution for \(J/\psi\) mesons produced in \(b\)-hadron decays is consistent with expectations. However, the results for prompt \(J/\psi\) production do not agree with predictions based on fixed-order non-relativistic QCD. This is the first measurement of the \(p_{\rm T}\) fraction carried by prompt \(J/\psi\) mesons in jets at any experiment.
The decays \(B^+\rightarrow J/\psi 3\pi^+ 2\pi^-\) and \(B^+\rightarrow \psi(2S) \pi^+\pi^+\pi^-\) are observed for the first time using a data sample corresponding to an integrated luminosity of ...\(3.0fb^{-1}\), collected by the LHCb experiment in proton-proton collisions at the centre-of-mass energies of 7 and 8 TeV. The branching fractions relative to that of \(B^+ \rightarrow \psi(2S)K^+\) are measured to be \begin{eqnarray*} \frac {\mathcal{B}\left(B^+\rightarrow J/\psi 3\pi^+ 2\pi^- \right)} {\mathcal{B}\left(B^+ \rightarrow \psi(2S)K^+ \right)} & = & \left(1.88\pm0.17\pm0.09\right)\times10^{-2}, \frac {\mathcal{B}\left(B^+\rightarrow \psi(2S) \pi^+\pi^+\pi^- \right)} {\mathcal{B}\left(B^+ \rightarrow \psi(2S)K^+ \right)} & = & \left(3.04\pm0.50\pm0.26\right)\times10^{-2}, \end{eqnarray*} where the first uncertainties are statistical and the second are systematic.
The production of \(t\overline{t}\), \(W+b\overline{b}\) and \(W+c\overline{c}\) is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb ...experiment, corresponding to an integrated luminosity of 1.98 \(\pm\) 0.02 \(\mbox{fb}^{-1}\). The \(W\) bosons are reconstructed in the decays \(W\rightarrow\ell\nu\), where \(\ell\) denotes muon or electron, while the \(b\) and \(c\) quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.
A search for the \(C\!P\)-violating strong decays \(\eta \to \pi^+\pi^-\) and \(\eta^\prime(958) \to \pi^+\pi^-\) has been performed using approximately \(2.5 \times 10^{7}\) events of each of the ...decays \(D^+ \to \pi^+\pi^+\pi^-\) and \(D_s^+ \to \pi^+\pi^+\pi^-\), recorded by the LHCb experiment. The data set corresponds to an integrated luminosity of 3.0 fb\(^{-1}\) of \(pp\) collision data recorded during LHC Run 1 and 0.3 fb\(^{-1}\) recorded in Run 2. No evidence is seen for \(D^+_{(s)} \to \pi^+ \eta^{(\prime)}\) with \(\eta^{(\prime)} \to \pi^+\pi^-\), and upper limits at 90% confidence level are set on the branching fractions, \(\mathcal{B}(\eta \to \pi^+\pi^-) < 1.6 \times 10^{-5}\) and \(\mathcal{B}(\eta^\prime \to \pi^+\pi^-) < 1.8 \times 10^{-5}\). The limit for the \(\eta\) decay is comparable with the existing one, while that for the \(\eta^\prime\) is a factor of three smaller than the previous limit.
The \(CP\) violation observables \(S\) and \(C\) in the decay channel \(B^0 \!\rightarrow D^+ D^-\) are determined from a sample of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, ...collected by the LHCb experiment and corresponding to an integrated luminosity of 3 fb\(^{-1}\). The observable \(S\) describes \(CP\) violation in the interference between mixing and the decay amplitude, and \(C\) parametrizes direct \(CP\) violation in the decay. The following values are obtained from a flavor-tagged, decay-time-dependent analysis: \begin{align*} S &= -0.54 \, ^{+0.17}_{-0.16} \, \text{(stat)} \pm 0.05 \, \text{(syst)}\,,\newline C &= \phantom{-}0.26 \, ^{+0.18}_{-0.17} \, \text{(stat)} \pm 0.02 \, \text{(syst)}\,. \end{align*} These values provide evidence for \(CP\) violation at a significance level of 4.0 standard deviations. The phase shift due to higher-order Standard Model corrections is constrained to a small value of \begin{align*} \Delta\phi = -0.16\,^{+0.19}_{-0.21}\,\text{rad}\,. \end{align*}
The effect of coastal upwelling on the recruitment and connectivity of coastal marine populations has rarely been characterized to a level of detail to be included into sound fishery management ...strategies. The gooseneck barnacle (Pollicipes pollicipes) fishery at the Cantabrian Coast (Northern Spain) is located at the fringes of the NW Spanish Upwelling system. This fishery is being co-managed through a fine-scale, interspersed set of protected rocks where each rock receives a distinct level of protection. Such interspersion is potentially beneficial, but the extent to which such spacing is consistent with mean larval dispersal distances is as yet unknown. We have simulated the spread of gooseneck barnacle larvae in the Central Cantabrian Coast using a high-resolution time-series of current profiles measured at a nearshore location. During a year of high upwelling activity (2009), theoretical recruitment success was 94% with peak recruitment predicted 56 km west of the emission point. However, for a year of low upwelling activity (2011) theoretical recruitment success dropped to 15.4% and peak recruitment was expected 13 km east of the emission point. This is consistent with a positive correlation between catch rates and the Integrated Upwelling Index, using a 4-year lag to allow recruits to reach commercial size. Furthermore, a net long-term westward larval transport was estimated by means of mitochondrial cytochrome c oxidase subunit I (COI) sequences for five populations in the Cantabrian Sea. Our results call into question the role of long distance dispersal, driven by the mesoscale processes in the area, in gooseneck barnacle populations and point to the prevalent role of small-scale, asymmetric connectivity more consistent with the typical scale of the co-management process in this fishery.
One of the most important activities of predictive maintenance of the transmission lines is the periodical inspection of each component (insulators, conductors, structures and others), besides the ...bio-physical environmental between them. This activity requires high efforts of the technical resources and also an important amount of money. CVG EDELCA, the big utility company in Venezuela, has been operating 2100 km of transmission lines in 765 kV, more than 3200 km in 400 kV, also 500 km in 230 kV and 115 kV. All of them have corridors that involve a very extensive areas that must be monitoring and the information obtain about the monitoring activity must be actual and available in real time and adequate formats for the good management decisions. Understanding the advantage of the new technologies in the multimedia area, CVG EDELCA since 2000 has been working with this technology in the transmission lines engineering designs (route study, survey, etc). Recently CVG EDELCA has been using this technology for preview ground wire replace studies for new optical ground wire (OPGW) in transmission line in operations, this experience is describe in this report
LHCb VELO Timepix3 Telescope Akiba, Kazu; Martin van Beuzekom; Boterenbrood, Henk ...
arXiv.org,
02/2019
Paper, Journal Article
Odprti dostop
The LHCb VELO Timepix3 telescope is a silicon pixel tracking system constructed initially to evaluate the performance of LHCb VELO Upgrade prototypes. The telesope consists of eight hybrid pixel ...silicon sensor planes equipped with the Timepix3 ASIC. The planes provide excellent charge measurement, timestamping and spatial resolution and the system can function at high track rates. This paper describes the construction of the telescope and its data acquisition system and offline reconstruction software. A timing resolution of 350~ps was obtained for reconstructed tracks. A pointing resolution of better than 2~\mum was determined for the 180~GeV/c %\gevc mixed hadron beam at the CERN SPS. The telescope has been shown to operate at a rate of 5 million particles~\unit{s^{-1}\cdot cm^{-2}} without a loss in efficiency.
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