# Posters

Derniers ajouts:
2016-08-16
11:54
$B^+_c$ meson production, decays and properties at LHCb
 Reference: Poster-2016-547 Created: 2016. -1 p Creator(s): Lusiani, Alberto We report the first study of the $B_c^+ \to K^+K^-\pi^+$ decay and an update of the measurement of the ratio of branching fractions $R_{K/\pi} \equiv {\cal B}(B_c^+\to J/\psi K^+)/{\cal B}(B_c^+\to J/\psi\pi^+)$. Both results use an integrated luminosity of $3.0fb^{-1}$ collected by the LHCb experiment in $pp$ collisions at centre-of-mass energies of 7 and 8 TeV. We measure $B_c^+ \to \chi_{c0}(\to K^+ K^-)\pi^+$ with $4.0\sigma$ significance and $\frac {\sigma(B_c^+)} {\sigma(B^+)}$ X ${\cal B}(B_c^+ \to \chi_{c0}\pi^+)$ to be $(9.8^{+3.4}_{-3.0}(stat) \pm 0.8(syst))$ X $10^{-6}$. The contribution of $B_c^+ \to K^+K^-\pi^+$ via $\overline{b}c$ weak annihilation for $m(K^-\pi^+) < 1.834 GeV$ is measured with $2.4\sigma$ significance. The ratio of branching fractions $R_{K/\pi} \equiv {\cal B}(B_c^+ \to J/\psi K^+) / {\cal B}(B_c^+ \to J/\psi \pi^+)$ is measured to be $R_{K/\pi} = 0.079 \pm 0.007(stat) \pm 0.003(syst)$. This result significantly improves the previous LHCb measurement. Related links:ICHEP 2016 © CERN Geneva Access to files

2016-08-15
11:54
SciFi - A large Scintillating Fibre Tracker for LHCb
 Reference: Poster-2016-546 Created: 2016. -1 p Creator(s): Quagliani, Renato The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40MHz using a trigger-less read-out system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with higher occupancy. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. Concept, design and operational parameters are driven by the challenging LHC environment including significant ionising and neutron radiation levels. Over a total active surface of 360 m2 the SciFi Tracker will use scintillating fibres (Ø 0.25 mm) read out by Silicon Photomultipliers (SiPMs). State-of-the-art multi-channel SiPM arrays are being developed to read out the fibres and a custom ASIC will be used to digitise the signals from the SiPMs. The project is now at the transition from R&D to series production. We will present the evolution of the design and the latest lab and test beam results. Related links:ICHEP 2016 © CERN Geneva Access to files

2016-08-08
12:26
LHCb-The LHCb trigger in Run II
 Reference: Poster-2016-545 Created: 2016. -1 p Creator(s): Michielin, Emanuele The LHCb trigger system has been upgraded to exploit the real-time alignment, calibration and analysis capabilities of LHCb in Run-II. An increase in the CPU and disk capacity of the event filter farm, combined with improvements to the reconstruction software, mean that efficient, exclusive selections can be made in the first stage of the High Level Trigger (HLT1). The output of HLT1 is buffered to the 5 PB of disk on the event filter farm, while the detector is aligned and calibrated in real time. The second stage, HLT2, performs complete, offline quality, event reconstruction. Physics analyses can be performed directly on this information, and for the majority of charm physics selections, a reduced event format can be written out, which permits higher event rates. Related links:Conference- 38th International Conference on High Energy Physics © CERN Geneva Access to files

2016-07-25
10:07
The Timepix3 Telescope and LHCb Upgrade R&D measurements
 Reference: Poster-2016-544 Keywords:  detector  test beam  particle identification Created: 2017. -1 p Creator(s): Rachwal, Bartlomiej The upgrade of the LHCb experiment will operate at an instantaneous luminosity of 2x10^33 cm^-2 s^-1 with a fully software based trigger, allowing to read out the detector at a rate of 40MHz. The tracking system will be redesigned: the vertex locator (VELO) will be replaced by a pixel-based detector, upstream of the magnet, a silicon mico-strip detector with a high granularity and an improved acceptance coverage, called the Upstream Tracker (UT), will replace the presently installed silicon strip tracker. The tracking system downstream of the magnet will be replaced by the Scintillating Fibre tracker (SciFi), which will consist of scintillating fibres read out by silicon photo-multipliers. We will present the ongoing work on vertex pixel detector and cover sensor technology, readout chip and a novel micro-channel cooling system, designed especially for the upgraded Velo. Related links:The 4th annual Large Hadron Collider Physics (LHCP2016) © CERN Geneva Access to files

2016-07-18
11:07
New ideas for axion like particle dark matter search
 Reference: Poster-2016-543 Note: Presented as part of the talk "Cross-disciplinary axion <--> chameleon detection + ID" by K. Zioutas. Keywords:  Axion  ALP  Hidden Photon  Wiggler  Dark Matter  Tore Supra  Toroidal mode  Cavity Created: 2012. -17 p Creator(s): Betz, Michael; Caspers, Fritz; Zioutas, Konstantin In the context of finding suitable large magnets for RF and microwave axion search, the Tore supra ring had been proposed. This Tokamak which could probably be made available for DM search has a huge volume and a strong magnetic field (30000 liter and 4.5 Tesla). It appears on a first glance, as an interesting candidate for this kind of experiment. One can find a suitable microwave mode which meets the condition that the RF electric field is parallel to the magnetostatic field. The eigenfrequency field pattern and Q factor for this mode and a few adjacent ones are calculated the some field patterns shown graphically. The use of the torus type cavity is not restricted to the Tore Supra. It can in principle be applied to any torus type structure also scaled up toward smaller dimensions and higher frequencies. In the second part of the slide presentation some alternatives and other cavity magnet concepts are shown and discussed. © CERN Geneva Access to files

2016-07-12
10:36
Results on dark matter searches with the ANTARES neutrino telescope
 Reference: Poster-2016-542 Keywords:  ANTARES, neutrino, dark matter, indirect search Created: 2016. -1 p Creator(s): Zornoza, Juande Neutrino telescopes have a wide scientific scope. One of their main goals is the detection of dark matter, for which they have specific advantages. The understanding of the nature of dark matter requires a multi-front approach since we still do not know many of their properties. Neutrino telescopes offer the possibility of look at several kinds of sources, not all of them available to other indirect searches. In this work we provide an overview of the results obtained by the ANTARES neutrino telescope, which has been taking data for almost ten years. It is installed in the Mediterranean Sea at a depth of 2475 m, off the coast of Toulon (France). The results presented in this work include searches for neutrino excess from several astrophysical sources. One of the most interesting ones is the Sun. Dark matter particles by the solar system would scatter with nuclei of the Sun, lose energy and accumulate in its centre. Among the final products of their annihilations, only neutrinos could escape. Therefore, a detection of high energy neutrinos from the Sun would be a very clean indication of dark matter, since no significant astrophysical backgrounds are expected, contrary to other indirect searches. Moreover, the limits from neutrino telescopes for spin-dependent cross section are the most restrictive ones. Another interesting source is the Galactic Centre, for which ANTARES has a better visibility than IceCube, due to its geographical location. This search gives limits on the annihilation cross section. Other dark matter searches carried out in ANTARES include the Earth and dwarf galaxies. Results with the most recent data sample will be presented, for the first time. © CERN Geneva Access to files

2016-06-28
11:38
Real-time alignment and calibration of the LHCb Detector in Run II
 Reference: Poster-2016-541 Created: 2016. -1 p Creator(s): Dujany, Giulio Stable, precise spatial alignment and PID calibration are necessary to achieve optimal detector performance. During Run2, LHCb has a new real-time detector alignment and calibration to allow equivalent performance in the online and offline reconstruction to be reached. This offers the opportunity to optimise the event selection by applying stronger constraints, and to use hadronic particle identification at the trigger level. The computing time constraints are met through the use of a new dedicated framework using the multi-core farm infrastructure for the trigger. The motivation for a real-time alignment and calibration of the LHCb detector is discussed from the operative and physics performance point of view. Specific challenges of this configuration are discussed, as well as the designed framework and its performance. Related links:The 2016 European School of High-Energy Physics © CERN Geneva Access to files

2016-06-15
15:54
Behind every great detector, there are lots of great people!
 Reference: Poster-2016-539 Keywords:  ATLAS  Detector  Collaboration  Collage  Portraits  Experiment  Education  Outreach  Poster Original source: AtlasPosterA1.pdf Created: 2008. -1 p Creator(s): Gagnon, Pauline; Goldfarb, Steven Photo collage of the ATLAS detector, using portraits of ATLAS collaboration members. Related links:Outreach Poster © CERN Geneva Access to file

2016-06-10
15:18
CERN Document Server
CERN Document Server

 Reference: Poster-2016-538 Created: 2016. -1 p Creator(s): Marian, Ludmila; Gabancho, Esteban; Witowski, Sebastian; Tzovanakis, Harris; Costa, Flavio [...] CERN Document Server, cds labs poster for OR2016 conference.CERN Document Server, cds labs poster for OR2016 conference. © CERN Geneva Access to files

2016-06-08
10:27
Measurement of the branching fraction ratio ${\cal B}(B_{c}^{+} \to \psi(2S)\pi^+)/{\cal B}(B_{c}^{+} \to J/\psi\pi^+)$
 Reference: Poster-2016-537 Created: 2016. -1 p Creator(s): An, Liupan Using the $pp$ collision data collected by LHCb at center-of-mass energies $\sqrt{s} \, = 7 \, {\rm TeV} \,$ and $8 \, {\rm TeV} \,$, corresponding to an integrated luminosity of $3 \, \mathrm{fb}^{-1} \,$, the ratio of the branching fraction of the $B_{c}^{+} \to \psi(2S)\pi^+$ decay relative to that of the $B_{c}^{+} \to J/\psi\pi^+$ decay is measured to be ${0.268 \pm 0.032\mathrm{\,(stat)} \pm 0.007\mathrm{\,(syst)} \pm 0.006\,(\mathrm{BF}) }$. The first uncertainty is statistical, the second is systematic, and the third is due to the uncertainties on the branching fractions of the $J/\psi \to \mu^{+}\mu^{-}$ and $\psi(2S) \to \mu^{+}\mu^{-}$ decays. To enhance the signal significance with limited $B_{c}^{+}$ statistics, the boosted decision tree selection is used to separate the signal and background effectively. The systematic uncertainties are discussed extensively. This measurement is consistent with the previous LHCb result, and the statistical uncertainty is halved. Related links:Beauty 2016 © CERN Geneva Access to files

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