CERN Accelerating science

Posters

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2015-05-22
15:55
Real-time alignment and calibration of the LHCb Detector in Run II
Reference: Poster-2015-488
Keywords:  LHCb
Created: 2015. -1 p
Creator(s): Dujany, Giulio; Storaci, Barbara

Stable, precise spatial alignment and PID calibration are necessary to achieve optimal detector performance. During Run2, LHCb will have 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.

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Conference LHCb poster
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2015-04-22
17:21
Data Management System of the DIRAC Project
Reference: Poster-2015-487
Keywords:  DIRAC  DataManagement  DFC  Catalogs  Bookkeeping
Created: 2015. -1 p
Creator(s): Haen, Christophe; Charpentier, Philippe; Tsaregorodtsev, Andrei

The DIRAC Interware provides a development framework and a complete set of components for building distributed computing systems. The DIRAC Data Management System (DMS) offers all the necessary tools to ensure data handling operations for small and large user communities. It supports transparent access to storage resources based on multiple technologies, and is easily expandable. The information on data files and replicas is kept in a File Catalog of which DIRAC offers a powerful and versatile implementation (DFC). Data movement can be performed using third party services including FTS3. Bulk data operations are resilient with respect to failures due to the use of the Request Management System (RMS) that keeps track of ongoing tasks. In this contribution we will present an overview of the DIRAC DMS capabilities and its connection with other DIRAC subsystems such as the Transformation System. The DIRAC DMS is in use by several user communities now. The contribution will present the experience of the LHCb experiment. The experience of other experiements as well as multi-VO DIRAC services with the use of the DIRAC DMS will be described.

Related links:
Conference LHCb poster
© CERN Geneva

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2015-04-21
11:23
LHCb : The DIRAC Web Portal 2.0
Reference: Poster-2015-486
Keywords:  DIRAC Web portal  custom web portals  distributed web application  high availability web application  personalised web pages  LHCb extension of the DIRAC portal
Created: 2015. -1 p
Creator(s): Mathe, Zoltan; Casajus Ramo, Adrian; Lazovsky, N; Stagni, Federico

For many years the DIRAC interware (Distributed Infrastructure with Remote Agent Control) has had a web interface, allowing the users to monitor DIRAC activities and also interact with the system. Since then many new web technologies have emerged, therefore a redesign and a new implementation of the DIRAC Web portal were necessary, taking into account the lessons learnt using the old portal. These new technologies allowed to build a more compact and more responsive web interface that is robust and that enables users to have more control over the whole system while keeping a simple interface. The framework provides a large set of "applications", each of which can be used for interacting with various parts of the system. Communities can also create their own set of personalised web applications, and can easily extend already existing web applications with a minimal effort. Each user can configure and personalise the view for each application and save it using the DIRAC User Profile service as RESTful state provider, instead of using cookies. The owner of a view can share it with other users or within a user community. Compatibility between different browsers is assured, as well as with mobile versions. In this paper, we present the new DIRAC Web framework as well as the LHCb extension of the DIRAC Web portal.

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LHCb poster
© CERN Geneva

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2015-04-17
11:21
CERN Document Server
Reference: Poster-2015-485
Keywords:  CDS  Multimedia  CHEP  CHEP2015  preserve  edit  share
Created: 2015. -1 p
Creator(s): Le Meur, Jean-Yves; Marian, Ludmila; Kasioumis, Nikos; Gabancho, Esteban; Witowski, Sebastian [...]

CERN Document Server, multimedia poster for CHEP2015 conference.

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CHEP2015
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2015-04-01
10:58
ALICE LHC Interface Project
Reference: Poster-2015-484
Keywords:  ALICE  LHC Interface
Created: 2013. -1 p
Creator(s): De Cataldo, G; Di Mauro, A

The LHC Interface Project (LHC_IF) ensures the online data exchange between the Large Hadron Collider (LHC) and ALICE, and the safe operation of the complex experiment-collider.

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2015-03-11
11:40
$\sin(2\beta)$ with $B^0 \rightarrow\!J/\!\psi K_\text{S}$ at the LHCb experiment
Reference: Poster-2015-482
Keywords:  LHCb
Created: 2015. -1 p
Creator(s): Niet, Ramon

The poster presents the recent measurement of $\sin(2\beta)$ using $B^0$ decays to the $J/\!\psi K_\text{S}$ final state. The measurement is based on a dataset corresponding to an integrated luminosity of 3.0$\,\text{fb}^{-1}$ collected with the LHCb experiment in proton-proton collisions at center-of-mass energies of 7 and 8 TeV. To control penguin pollutions in the determination of $\sin(2\beta)$, $B_s^0$ decays to the same final state can be analysed. The results of the corresponding analysis are presented as well.

Related links:
LHCC conference poster
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2015-03-11
11:32
Study of the rare $B^{0}_{s}$ and $B^{0}$ decays into the $\pi^{+}\pi^{-}\mu^{+}\mu^{-}$ final state at LHCb
Reference: Poster-2015-481
Keywords:  LHCb
Created: 2015. -1 p
Creator(s): Komarov, Ilya

A search for the rare decays B0s->pi pi mu mu and B0->pi pi mu mu is performed in a data set corresponding to an integrated luminosity of 3.0 fb-1 collected by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7 and 8TeV. Decay candidates with pion pairs that have invariant mass in the range 0.5--1.3 GeV/c2 and with muon pairs that do not originate from a resonance are considered. The first observation of the decay B0s->pi pi mu mu and the first evidence of the decay B0->pi pi mu mu are obtained and the branching fractions, restricted to the dipion-mass range considered, are measured to be Br(B0s->pi pi mu mu) = (8.6 +/- 1.5 (stat) +/- 0.7 (syst) +/- 0.7 (norm))*10^-8 and Br(B0->pi pi mu mu) = (2.11 +/- 0.51 (stat) +/- 0.15 (syst) +/- 0.16 (norm)) *10^-8, where the third uncertainty is due to the branching fraction of the decay B0->J/psi K*, used as a normalisation.

Related links:
LHCC conference poster
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2015-03-11
11:21
Topological Trigger Developments
Reference: Poster-2015-480
Keywords:  LHCb
Created: 2015. -1 p
Creator(s): Likhomanenko, Tatiana

The main b-physics trigger algorithm used by the LHCb experiment is the so-called topological trigger. The topological trigger selects vertices which are a) detached from the primary proton-proton collision and b) compatible with coming from the decay of a b-hadron. In the LHC Run 1, this trigger utilized a custom boosted decision tree algorithm, selected an almost 100% pure sample of b-hadrons with a typical efficiency of 60-70%, and its output was used in about 60% of LHCb papers. This talk presents studies carried out to optimize the topological trigger for LHC Run 2. In particular, we have carried out a detailed comparison of various machine learning classifier algorithms, e.g., AdaBoost, MatrixNet and uBoost. The topological trigger algorithm is designed to select all "interesting" decays of b-hadrons, but cannot be trained on every such decay. Studies have therefore been performed to determine how to optimize the performance of the classification algorithm on decays not used in the training. These include cascading, ensembling and blending techniques. Furthermore, novel boosting techniques have been implemented that will help reduce systematic uncertainties in Run 2 measurements. We demonstrate that the reoptimized topological trigger is expected to significantly improve on the Run 1 performance for a wide range of b-hadron decays

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LHCC conference poster
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2015-03-11
09:17
Flavour Tagging with the LHCb experiment
Reference: Poster-2015-479
Keywords:  LHCb
Created: 2015. -1 p
Creator(s): Birnkraut, Alex

Measurements of flavour oscillations and time-dependent CP asymmetries in neutral B meson systems require knowledge of the b quark production flavour. This identification is performed by the Flavour Tagging.

Related links:
LHCC conference poster
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2015-03-06
17:15
Measurement of the semileptonic $CP$ asymmetry in $B^0 - \bar {B^0}$ mixing
Reference: Poster-2015-478
Keywords:  LHCb
Created: 2015. -1 p
Creator(s): De Vries, Jacco

The semileptonic CP asymmetry in B0−B⎯⎯⎯0 mixing, adsl, is measured in proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb−1, recorded by the LHCb experiment. Semileptonic B0 decays are reconstructed in the inclusive final states D−μ+ and D∗−μ+, where the D− meson decays into the K+π−π− final state, and the D∗− meson into the D⎯⎯⎯0(→K+π−)π− final state. The asymmetry between the numbers of D(∗)−μ+ and D(∗)+μ− decays is measured as a function of the decay time of the B0 mesons. The CP asymmetry is measured to be adsl=(−0.02±0.19±0.30)%, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of adsl to date and is consistent with the prediction from the Standard Model.

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LHCC conference poster
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Open Days 2013 Posters (58)