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Derniers ajouts:
2019-07-16
13:55
Particle identification performance of the LHCb experiment in Run 2
Reference: Poster-2019-697
Created: 2019. -1 p
Creator(s): Douglas, Lauren Marie; De Cian, Michel

The LHCb particle identification (PID) system is composed of two ring-imaging Cherenkov detectors, a series of muon chambers and a calorimeter system. A novel strategy has been introduced in Run 2, where the selection of PID calibration samples for charged particles and neutrals is implemented in the LHCb software trigger. A further processing of the data is required in order to provide samples for the determination of PID performance, which is achieved through a centralised production that makes highly efficient use of computing resources. This talk covers the major steps of the implementation, and highlights the PID performance achieved in Run 2.

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2019-07-16
10:51
Real-time alignment and temperature dependency of the LHCb Vertex Detector
Reference: Poster-2019-696
Created: 2019. -1 p
Creator(s): Mitreska, Biljana

The accuracy of the LHCb Vertex Locator (VELO) has ensured excellent detector performance, with a track reconstruction efficiency above 98%, and a vertex resolution along the beam axis of about 70 microns. The real-time alignment and calibration procedure developed by the LHCb experiment for Run 2 (2015-2018) for the full detector, including the VELO, provided extremely stable conditions during the full data taking period. In 2010, a significant shrinkage of the VELO modules was observed at the operating temperature of -30 degrees with respect to survey measurements made at ambient temperature. This has been confirmed by laboratory measurements on a single module. In a recent study, using a dedicated LHCb data sample taken over a range of VELO temperatures, the variation of the detector position as a function of temperature has been evaluated. An overview of the VELO alignment procedure and its performance during Run 2 will be presented, with an emphasis on the study of the temperature dependence.

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2019-06-27
14:45
LHCb - Recent results on the CKM angle $\gamma$ measurement at LHCb and prospect for Run III and Run IV
Reference: Poster-2019-695
Created: 2019. -1 p
Creator(s): Krupa, Wojciech

The CKM angle γ is the least precise measured parameter of the Unitary Triangle. Discrepancies between precise measurements of the CKM angle γ in the tree-level and loop dominated processes might provide evidence of New Physics - beyond the Standard Model. The value can be well determined by exploiting the interference between favored 𝐵 → 𝐷𝐾 decay). Selected results of the Cabibbo-Kobayashi-Maskawa (CKM) angle γ measurements, with special attention for 𝐵 → 𝐷𝐾 decays family, obtained at the LCHb will be discussed. A quick overview of the upgrade of the LHCb spectrometer and prospect for future measurements during Run III and Run IV at LHC will be also presented.

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Conference LHCb Poster
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2019-06-27
14:27
LHCb-Discovery of CP violation in charm decays at LHCb experiment and prospects for Run III and Run IV
Reference: Poster-2019-694
Created: 2019. -1 p
Creator(s): Ryzka, Jakub

The existence of CP violation in the decays of strange and beauty mesons is very well established experimentally. On the contrary, CP violation in the decays of charmed particles has never been observed before (2018). During the LHC Run I and Run II the LHCb collaboration has collected a huge sample of charmed hadrons. This sample enables some of the most sensitive searches for CP violation ever performed. In this presentation, the results of the latest search for time-integrated CP violation in D0→K−K+ and D0→π−π+ decays, performed using the full data set collected by LHCb corresponding to an integrated luminosity of 9fb−1, will be discussed. The flavour of the decaying charm meson is determined by looking at the charge of the pion from the strong decay D∗(2010)+→D0π+ for promptly produced D0, or at the charge of the muon in semileptonic B0¯,B−→D0μ−ν¯μX decays for secondary production of D0. Also a brief prospects for further analyses (especially including Ξc barion decay) will be presented.

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Conference LHCb Poster
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2019-05-28
16:31
CP-violation in B-meson decays
Reference: Poster-2019-693
Created: 2019. -1 p
Creator(s): Koliiev, Serhii

Coming soon

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Conference LHCb Poster
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2019-05-23
14:45
Search for time-dependent CP violation in Charm at LHCb
Reference: Poster-2019-692
Keywords:  LHCb  CP violation  Charm
Created: 2019. -1 p
Creator(s): Pajero, Tommaso

A measurement of the time-dependent $CP$ asymmetries in the decay of $D^{0}$ mesons into $K^{+}K^{-}$ and $\pi^{+}\pi^{-}$ final states, using the data collected by LHCb during 2015—2016, is presented. Its average with the LHCb Run 1 results is the most precise measurement of the $CP$ violation parameter $A_\Gamma$ to date. No evidence of $CP$ violation is found.

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Conference LHCb Poster
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2019-05-23
10:57
Time-dependent CP violation in $B^0_s$ decays at LHCb
Reference: Poster-2019-691
Keywords:  LHCb  CP Violation
Created: 2019. -1 p
Creator(s): Gabriel, Emmy Pauline Maria

Time-dependent CP-violation measurements of beauty mesons allow the determination of the mixing-induced CP-violating phases phi_s and beta. The measurement of the phase phi_s in the Bs-Bsbar system is one of the key goals of the LHCb experiment due to the sensitivity to physics beyond the Standard Model (BSM). The CP-violating phase is of interest in penguin dominated b->s transitions, in addition to that of tree-level decays, which test the flavour changing neutral current interaction describing B mixing. Both are sensitive to BSM phases and provide valuable tests and constraints. We present new results of time-dependent CP violation using data collected at LHCb between 2011 and 2016.

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Conference LHCb Poster
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2019-05-14
15:55
THE NEW INJECTION REGION OF THE CERN PS BOOSTER
Reference: Poster-2019-690
Keywords:  PSB  PS Booster  Charge exchange Injection  Stripping  H-
Created: 2019. -1 p
Creator(s): Weterings, Wim; Bracco, Chiara; Jorat, Louise Olivia; Meddahi, Malika; Noulibos, Remy [...]

During the Long Shutdown 2 (LS2) at CERN, the new Linac4 (L4) accelerator will be connected to the PS Booster (PSB) to inject 160 MeV H− beam into the 4 superposed PSB rings. In order to achieve this, we have designed, built and pre-assembled a completely new H− charge-exchange injection chicane system, with a carbon stripping foil unit to convert the negative hydrogen ions into protons by stripping off the electrons. In parallel, we have built and installed a test stand in the L4 transfer line enabling us to gain valuable experience with operation of the stripping foil system and to evaluate different foil types during the L4 reliability runs. This paper describes the final design of the new PSB injection region and reports on the important test results obtained with the stripping foil test stand.

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2019-05-13
11:24
DESIGN AND CONSTRUCTION OF THE CERN SPS EXTRACTION PROTECTION ELEMENTS FOR LIU
Reference: Poster-2019-689
Created: 2019. -1 p
Creator(s): Balhan, Bruno

At CERN, the SPS synchrotron is equipped with two fast extraction channels towards the LHC. As a part of the LHC injector upgrade project (LIU), the protection devic- es upstream of the septa in both extraction channels will be upgraded. Various failure scenarios have been studied and presented in the past, but the definitive approach for the equipment protection upgrade for each channel has now been determined. This paper describes the consequences of the most significant failure scenarios and the impact of the heat deposition in the diluter. The resulting material stresses are evaluated. The detailed layout for the extraction protection equipment for each extraction channel is outlined. The final layout consists of a extended diluter in Long Straight Section (LSS) 6 (TPSG6) and the installation of an additional mov- able absorber (TPSC4) upstream of the quadrupole in front of the existing protection equipment in LSS 4. The detailed mechanical design of the TPSC4 and the construction status of both TPSC4 and TPSG6 are discussed.

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2019-04-05
14:12
The LHCb Vertex Detector Upgrade. The prototypes study with the Timepix3 Telescope
Reference: Poster-2019-688
Created: 2019. -1 p
Creator(s): Rachwal, Bartlomiej

A dedicated irradiation programme with a particle beam followed by detailed studies are essential for proper evaluation of detector prototypes and predict their performance after accumulating the predicted particle fluence at the end of their lifetime. In order to perform precise measurements with the LHCb VELO (Vertex Locator) detector prototypes a dedicated high-resolution pixel beam telescope was developed based on 8 Timepix3 detector planes. This telescope has been taking data at CERN in the PS and SPS facilities since 2014. The Timepix3 can operate in a trigger less mode (data driven readout) with very precise timestamps. The data produced by the telescope can easily incorporate the signals from the Device Under Test (DUT) and in particular for Timepix3 devices the analysis is straight forward. The offline analysis compares the performance after irradiation with several fluences of protons or neutrons from 2 to 8 $\times 10^{15}$ 1-MeV $n_{eq}/cm^2$ ; different silicon substrates (n-on-p or n-on-n), distances from last pixel to the edge, guard rings designs and different vendors. Charge collection efficiencies, track resolution, eta correction are of particular interest as function of fluence. The presentation will describe the detailed LHCb VELO upgrade design choices as well as with some highlights of the Timepix3 Telescope operational performance.

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VIII International Course "Detectors and Electronics for High Energy Physics, Astrophysics, Space Applications and Medical Physics"
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