The LHCb Turbo Stream

Benson, S.; Gligorov, Vladimir; Vesterinen, M.; Williams, John

doi:10.1088/1742-6596/664/8/082004

Cited by 27 publications

(24 citation statements)

References 4 publications

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“…An important feature of this search is that it can be made fully data driven, since the A signal rate can be inferred from measurements of the SM prompt µ + µ − spectrum. The excellent invariant-mass and vertex resolution of the LHCb detector, along with its unique particle-identification and real-time data-analysis capabilities [50,51], make it highly sensitive to A → µ + µ − . We derive the LHCb sensitivity for both prompt and dis-placed A decays, and show that LHCb can probe otherwise inaccessible regions of the m A -2 plane.…”

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confidence: 99%

Proposed Inclusive Dark Photon Search at LHCb

et al. 2016

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We propose an inclusive search for dark photons A 0 at the LHCb experiment based on both prompt and displaced dimuon resonances. Because the couplings of the dark photon are inherited from the photon via kinetic mixing, the dark photon A 0 → μ þ μ − rate can be directly inferred from the off-shell photon γ Ã → μ þ μ − rate, making this a fully data-driven search. For run 3 of the LHC, we estimate that LHCb will have sensitivity to large regions of the unexplored dark-photon parameter space, especially in the 210-520 MeV and 10-40 GeV mass ranges. This search leverages the excellent invariant-mass and vertex resolution of LHCb, along with its unique particle-identification and real-time data-analysis capabilities. DOI: 10.1103/PhysRevLett.116.251803 Dark matter-firmly established through its interactions with gravity-remains an enigma. Though there are increasingly stringent constraints on direct couplings between visible matter and dark matter, little is known about the dynamics within the dark sector itself. An intriguing possibility is that dark matter might interact via a new dark force, felt only feebly by standard model (SM) particles. This has motivated a worldwide effort to search for dark forces and other portals between the visible and dark sectors (see Ref.[1] for a review).A particularly compelling dark-force scenario is that of a dark photon A 0 which has small SM couplings via kinetic mixing with the ordinary photon through the operator ðϵ=2ÞF 0 μν F μν [2][3][4][5][6][7]. Previous beam dump [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], fixed target [22][23][24], collider [25][26][27], and rare meson decay [28][29][30][31][32][33][34][35][36][37] experiments have already played a crucial role in constraining the dark photon mass m A 0 and kinetic-mixing strength ϵ 2 . Large regions of the m A 0 − ϵ 2 plane, however, are still unexplored (see Fig. 1). Looking to the future, a wide variety of innovative experiments have been proposed to further probe the dark photon parameter space [38][39][40][41][42][43][44][45][46][47][48], though new ideas are needed to test m A 0 > 2m μ and ϵ 2 ∈ ½10 −7 ; 10 −11 .In this Letter, we propose a search for dark photons via the decayat the LHCb experiment during LHC run 3 (scheduled for 2021-2023). The potential of LHCb to discover dark photons was recently emphasized in Ref.[48], which exploits the exclusive charm decay modeHere, we consider an inclusive approach where the production mode of A 0 need not be specified. An important feature of this search is that it can be made fully data driven, since the A 0 signal rate can be inferred from measurements of the SM prompt μ þ μ − spectrum. The excellent invariant-mass and vertex resolution of the LHCb detector, along with its unique particle-identification and real-time data-analysis capabilities [50,51], make it highly sensitive to A 0 → μ þ μ − . We derive the LHCb sensitivity for both prompt and displaced A 0 decays, and show that LHCb can probe otherwise inaccessible regions of the m A 0 − ϵ 2 plane...

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confidence: 99%

Proposed Inclusive Dark Photon Search at LHCb

et al. 2016

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“…This approach, first implemented at the LHC by the CMS experiment in 2011, is referred to as data scouting [24]. A similar data collection strategy has also been recently introduced by the LHCb experiment [25].This Letter presents a search for narrow resonances decaying into two jets using pp interactions at √ s = 8 TeV. The study is performed on the scouting data collected with the CMS detector during 2012.…”

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confidence: 99%

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Search for Narrow Resonances in Dijet Final States ats=8 TeVwith the Novel CMS Technique of Data Scouting

Khachatryan¹,

Sirunyan²,

Tumasyan³

et al. 2016

Phys. Rev. Lett.

107

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A search for narrow resonances decaying into dijet final states is performed on data from proton-proton collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 18.8 fb^{-1}. The data were collected with the CMS detector using a novel technique called data scouting, in which the information associated with these selected events is much reduced, permitting collection of larger data samples. This technique enables CMS to record events containing jets at a rate of 1 kHz, by collecting the data from the high-level-trigger system. In this way, the sensitivity to low-mass resonances is increased significantly, allowing previously inaccessible couplings of new resonances to quarks and gluons to be probed. The resulting dijet mass distribution yields no evidence of narrow resonances. Upper limits are presented on the resonance cross sections as a function of mass, and compared with a variety of models predicting narrow resonances. The limits are translated into upper limits on the coupling of a leptophobic resonance Z_{B}^{'} to quarks, improving on the results obtained by previous experiments for the mass range from 500 to 800 GeV.

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“…One more change introduced in the online data processing workflow for Run 2 is the Turbo Stream [5]. This concerns reconstruction data processing done within the HLT farm in contrast to "normal" offline data processing as described in section 3.…”

Section: Pos(isgc2015)005mentioning

confidence: 99%

The LHCb Distributed Computing Model and Operations during LHC Runs 1, 2 and 3

Roiser¹,

Diaz²,

Salichos³

et al. 2016

Proceedings of International Symposium on Grids and Clouds 2015 — PoS(ISGC2015)

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2 PoS(ISGC2015)005LHCb is one of the four main high energy physics experiments currently in operation at the Large Hadron Collider at CERN, Switzerland. This contribution reports on the experience of the computing team during LHC Run 1, the current preparation for Run 2 and a brief outlook on plans for data taking and its implications for Run 3. Furthermore a brief introduction on LHCbDIRAC, i.e. the tool to interface the experiment distributed computing resources for its data processing and data management operations is given. During Run 1 several changes in the online filter farms had impacts on the computing operations and the computing model such as the replication of physics data, the data processing workflows and the organisation of processing campaigns. The strict MONARC model originally foreseen for LHC distributed computing was changed. Furthermore several changes and simplifications in the tools for distributed computing were taken e.g. for the software distribution, the replica catalog service or the deployment of conditions data. The reasons, implementations and implications for all these changes will be discussed. For Run 2 the running conditions of the LHC will change which will also have an impact on the distributed computing as the output rate of the high level trigger (HLT) approximately will double. This increased load on computing resources and also changes in the high level trigger farm, which will allow a final calibration of data will have a direct impact on the computing model. In addition more simplifications in the usage of tools are foreseen for Run 2, such as the consolidation of data access protocols, the usage of a new replica catalog and several adaptions in the core the distributed computing framework to serve the additional load. In Run 3 the trigger output rate is foreseen to increase. One of the changes in HLT, to be tested during Run 2 and taken further in Run 3, which allows direct output of physics data without offline reconstruction will be discussed. LHCb also strives for the inclusion of cloud and virtualised infrastructures for its distributed computing needs, including running on IaaS infrastructures such as Openstack or on hypervisor only systems using Vac, a self organising cloud infrastructure. The usage of BOINC for volunteer computing is currently in preparation and tested. All these infrastructures, in addition to the classical grid computing, can be served by a single service and pilot system. The details of these different approaches will be discussed.

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The LHCb Turbo Stream

Cited by 27 publications

References 4 publications

Proposed Inclusive Dark Photon Search at LHCb

Proposed Inclusive Dark Photon Search at LHCb

Search for Narrow Resonances in Dijet Final States ats=8 TeVwith the Novel CMS Technique of Data Scouting

The LHCb Distributed Computing Model and Operations during LHC Runs 1, 2 and 3

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