5,214 research outputs found
File-based data flow in the CMS Filter Farm
No full textDuring the LHC Long Shutdown 1, the CMS Data Acquisition system underwent a partial redesign to replace obsolete network equipment, use more homogeneous switching technologies, and prepare the ground for future upgrades of the detector front-ends. The software and hardware infrastructure to provide input, execute the High Level Trigger (HLT) algorithms and deal with output data transport and storage has also been redesigned to be completely file- based. This approach provides additional decoupling between the HLT algorithms and the input and output data flow. All the metadata needed for bookkeeping of the data flow and the HLT process lifetimes are also generated in the form of small "documents" using the JSON encoding, by either services in the flow of the HLT execution (for rates etc.) or watchdog processes. These "files" can remain memory-resident or be written to disk if they are to be used in another part of the system (e.g. for aggregation of output data). We discuss how this redesign improves the robustness and flexibility of the CMS DAQ and the performance of the system currently being commissioned for the LHC Run 2.National Science Foundation (U.S.)United States. Department of Energ
Online data handling and storage at the CMS experiment
No full textDuring the LHC Long Shutdown 1, the CMS Data Acquisition (DAQ) system underwent a partial redesign to replace obsolete network equipment, use more homogeneous switching technologies, and support new detector back-end electronics. The software and hardware infrastructure to provide input, execute the High Level Trigger (HLT) algorithms and deal with output data transport and storage has also been redesigned to be completely file- based. All the metadata needed for bookkeeping are stored in files as well, in the form of small documents using the JSON encoding. The Storage and Transfer System (STS) is responsible for aggregating these files produced by the HLT, storing them temporarily and transferring them to the T0 facility at CERN for subsequent offline processing. The STS merger service aggregates the output files from the HLT from ~62 sources produced with an aggregate rate of ~2GB/s. An estimated bandwidth of 7GB/s in concurrent read/write mode is needed. Furthermore, the STS has to be able to store several days of continuous running, so an estimated of 250TB of total usable disk space is required. In this article we present the various technological and implementation choices of the three components of the STS: the distributed file system, the merger service and the transfer system.United States. Department of EnergyNational Science Foundation (U.S.
A New Event Builder for CMS Run II
No full textThe data acquisition system (DAQ) of the CMS experiment at the CERN Large Hadron Collider (LHC) assembles events at a rate of 100 kHz, transporting event data at an aggregate throughput of 100GB/s to the high-level trigger (HLT) farm. The DAQ system has been redesigned during the LHC shutdown in 2013/14. The new DAQ architecture is based on state-of-the-art network technologies for the event building. For the data concentration, 10/40 Gbps Ethernet technologies are used together with a reduced TCP/IP protocol implemented in FPGA for a reliable transport between custom electronics and commercial computing hardware. A 56 Gbps Infiniband FDR CLOS network has been chosen for the event builder. This paper discusses the software design, protocols, and optimizations for exploiting the hardware capabilities. We present performance measurements from small-scale prototypes and from the full-scale production system.United States. Department of EnergyNational Science Foundation (U.S.
Search for WW and WZ Resonances Decaying to Electron, Missing ET, and Two Jets in pp̅ Collisions at √s=1.96 TeV.
No full textUsing data from 2.9 fb[superscript -1] of integrated luminosity collected with the CDF II detector at the Tevatron, we search for resonances decaying into a pair of on-shell gauge bosons, WW or WZ, where one W decays into an electron and a neutrino, and the other boson decays into two jets. We observed no statistically significant excess above the expected standard model background, and we set cross section limits at 95% confidence level on G* (Randall-Sundrum graviton), Z′, and W′ bosons. By comparing these limits to theoretical cross sections, mass exclusion regions for the three particles are derived. The mass exclusion regions for Z′ and W′ are further evaluated as a function of their gauge coupling strength
The use of the tau in new particle searches at DELPHI
No full textSeveral new particle searches have been performed in the DELPHI experiment involving tau leptons in the resulting final state. The topology and special characteristics of the tau leptons have been used to discriminate the signal from the Standard Model background. Limits on new particles have been set, playing an important role the channels with tau leptons.Several new particle searches have been performed in the DELPHI experiment involving tau leptons in the resulting final state. The topology and special characteristics of the tau leptons have been used to discriminate the signal from the Standard Model background. Limits on new particles have been set, playing an important role the channels with tau leptons
Study of the electric properties of magnetic materials based on fe using the Debye and Cole-Cole models
No full textgraficas, tablasEn esta tesis se presenta un estudio de las propiedades de impedancia y función dieléctrica de los vidrios metálicos Fe70Nb10B20 y [(Fe50Co50)75B20Si5]96Nb4mediante el uso de la resonancia ferromagnética de una pequeña bobina. Para este fin la muestra se colocó dentro de la bobina pequeña y éste conjunto a su vez se colocó en el centro de una bobina de Helmholtz. Las medidas de impedancia se realizaron en el rango de frecuencia 0 < 30 < MHz para diferentes campos magnéticos a temperatura ambiente. El campo AC generado por el pequeño solenoide es del orden de 3 Oe RMS y el campo generado por la bobina de Helmholtz fue de HDC = 0, 5, 10, 20, 30 y 40 Oe. A partir de las medidas experimentales se determinó un circuito equivalente constituido por una inductancia principal conectada en serie con una resistencia, un capacitor y una inductancia secundaria que están conectadas en paralelo entre ellas. Además, para el tratamiento de datos experimentales se desarrolló en Matlab un algoritmo de ajuste numérico por inteligencia artificial. Se realizó un estudio estadístico del sistema de medición constituidos por bobina y (bobina y baquela), encontrando una variación de las medidas de impedancia por debajo del 1.5% en todo el rango de frecuencia utilizado, para los diferentes campos DC empleados. Inicialmente se caracterizó la respuesta de la bobina ante el campo magnético DC y la frecuencia. Se encontró
que presenta el fenómeno de resonancia ferromagnética, posteriormente se usó un postamuestras constituido de baquelita que se colocó al interior de la pequeña bobina para formar el sistema (bobina y baquela). Se encontró que esta baquelita anula la resonancia ferromagnética de la bobina. Una vez caracterizado el sistema de medición se realizaron las mediciones de impedancia de los materiales anteriormente mencionados. Se encontró que ambos restituyen la resonancia ferromagnética de la bobina, lo cual refleja que ellos exhiben una resonancia natural. El circuito equivalente describe bien la respuesta de impedancia de ambas muestras en el rango de frecuencia donde se presenta la resonancia principal (0 ≤ ω ≤ 5 ∙E7 rad/s). Usando la relación entre la función dieléctrica y la impedancia se
determinó un intervalo de frecuencia en donde la función dieléctrica de las
muestras es descrita apropiadamente por un diagrama de Cole-Cole (2MHz ≤ f ≤ 2.9MHz) (Texto tomado de la fuente)In this thesis a study of the impedance properties and dielectric function of the metallic glasses Fe70Nb10B20 and [(Fe50Co50)75B20Si5]96Nb4 is presented by using the ferromagnetic resonance of a small coil. For this purpose, the sample was placed inside the small coil and this set was placed in the centre of a Helmholtz coil. Impedance measurements were made in the frequency range 0 < 30 < MHz for different magnetic fields at room temperature. The AC field generated by the small solenoid is of the order of 3 Oe RMS and the field generated by the Helmholtz coil was HDC = 0, 5, 10, 20, 30 y 40 Oe. From the experimental measurements, an equivalent circuit was determined consisting of a main inductance connected in series with a resistance, a capacitor and a secondary inductance that are connected in parallel between them. In addition, for the treatment of experimental data, a numerical adjustment algorithm by artificial intelligence was developed in Matlab. A statistical study of the measurement system constituted by coil and (coil and drum) was carried out, finding a variation of the impedance measurements below 1.5% in the entire frequency range used, for the different DC fields used. Initially, the response of the coil to the DC magnetic field and frequency was characterized. It was found that it presents the phenomenon of ferromagnetic resonance, later a Bakelite post-sample was used, which was placed inside the small coil to form the system (coil and Bakelite). This Bakelite was found to nullify the ferromagnetic resonance of the coil. Once the measurement system was characterized, the impedance measurements of the aforementioned materials were performed. Both were found to restore the ferromagnetic resonance of the coil, which reflects that they exhibit a natural resonance. The equivalent circuit describes well the impedance response of both samples in the frequency range where the main resonance occurs (0≤≤5∙10 7rad/s). Using the relationship between the dielectric function and the impedance, a frequency range was determined where the dielectric function of the samples is appropriately described by a Cole-Cole diagram (2MHz≤≤2.9MHz)MaestríaMagnetismoCiencias Naturales.Sede Manizale
New constraints on tectonism and magmatism from the eastern sector of the Trans-Mexican Volcanic Belt (Chignahuapan Horst, Puebla, México)
No full textThe Quaternary Acoculco (<2.7 my) and Los Humeros (<46 ky) calderas, located in the eastern sector of the Trans-Mexican Volcanic Belt (TMVB), are separated by a regional structure known as the Chignahuapan Horst (ChH). The tectonic and magmatic evolution of the ChH comprises four stages: 1) Upper Cretaceous-Paleocene Laramide orogeny, related to the deformation of sedimentary successions; 2) a sedimentary hiatus followed by the initial stage of the TMVB (Middle Miocene); 3) a Miocene NE-SW oriented extension responsible for the NW- SE normal faults that controlled the volcanic processes and the emplacement of calc-alkaline magmas that formed the Aquixtla sequence; 4) a magmatic hiatus prolonged until 1.6 ± 0.15 my; 5) Pliocene-Quaternary normal faults controlled the emplacement of tholeiitic-transitional magmas and the monogenetic volcanism distribution that formed the Apizaco-Chignahuapan sequence.
Coevally to the Miocene NE-SW and Pliocene-Quaternary NW-SE tectonic extensional phases, NE-SW and NW- SE transfer faults were developed. NE-SW normal faults and NW-SE strike-slip faults correspond to fault systems optimally oriented with the current stress field, thus, these faults can be considered as potentially active structures controlling magma emplacement and the distribution of volcanic structures at the surface.The Quaternary Acoculco (<2.7 my) and Los Humeros (<46 ky) calderas, located in the eastern sector of the Trans-Mexican Volcanic Belt (TMVB), are separated by a regional structure known as the Chignahuapan Horst (ChH). The tectonic and magmatic evolution of the ChH comprises four stages: 1) Upper Cretaceous-Paleocene Laramide orogeny, related to the deformation of sedimentary successions; 2) a sedimentary hiatus followed by the initial stage of the TMVB (Middle Miocene); 3) a Miocene NE-SW oriented extension responsible for the NW-SE normal faults that controlled the volcanic processes and the emplacement of calc-alkaline magmas that formed the Aquixtla sequence; 4) a magmatic hiatus prolonged until 1.6 ± 0.15 my; 5) Pliocene-Quaternary normal faults controlled the emplacement of tholeiitic-transitional magmas and the monogenetic volcanism distribution that formed the Apizaco-Chignahuapan sequence. Coevally to the Miocene NE-SW and Pliocene-Quaternary NW-SE tectonic extensional phases, NE-SW and NW-SE transfer faults were developed. NE-SW normal faults and NW-SE strike-slip faults correspond to fault systems optimally oriented with the current stress field, thus, these faults can be considered as potentially active structures controlling magma emplacement and the distribution of volcanic structures at the surface
Hints of large tanβ in flavour physics
No full textAbstractMotivated by the first evidence of the Bu→τν transition reported by Belle [Belle Collaboration, K. Ikado, et al., hep-ex/0604018] and by the precise ΔMBs measurement by CDF [CDF Collaboration, G. Gomez-Ceballos, Talk presented at FPCP 2006, Vancouver, Canada, 9–12 April 2006, http://fpcp2006.triumf.ca/; D∅ Collaboration, V. Abazov, hep-ex/0603029], we analyse these and other low-energy observables in the framework of the MSSM at large tanβ. We show that for heavy squarks and A terms (Mq˜, AU ≳1 TeV) such scenario has several interesting virtues. It naturally describes: (i) a suppression of B(Bu→τν) of (10–40)%, (ii) a sizable enhancement of (g−2)μ, (iii) a heavy SM-like Higgs (mh0∼120 GeV), (iv) small non-standard effects in ΔMBs and B(B→Xsγ) (in agreement with present observations). The possibilities to find more convincing evidences of such scenario, with improved data on B(Bu→τν), B(Bs,d→ℓ+ℓ−) and other low-energy observables, are briefly discussed
CMS distributed computing workflow experience
No full textThe vast majority of the CMS Computing capacity, which is organized in a tiered hierarchy, is located away from CERN. The 7 Tier-1 sites archive the LHC proton-proton collision data that is initially processed at CERN. These sites provide access to all recorded and simulated data for the Tier-2 sites, via wide-area network (WAN) transfers. All central data processing workflows are executed at the Tier-1 level, which contain re-reconstruction and skimming workflows of collision data as well as reprocessing of simulated data to adapt to changing detector conditions. This paper describes the operation of the CMS processing infrastructure at the Tier-1 level. The Tier-1 workflows are described in detail. The operational optimization of resource usage is described. In particular, the variation of different workflows during the data taking period of 2010, their efficiencies and latencies as well as their impact on the delivery of physics results is discussed and lessons are drawn from this experience. The simulation of proton-proton collisions for the CMS experiment is primarily carried out at the second tier of the CMS computing infrastructure. Half of the Tier-2 sites of CMS are reserved for central Monte Carlo (MC) production while the other half is available for user analysis. This paper summarizes the large throughput of the MC production operation during the data taking period of 2010 and discusses the latencies and efficiencies of the various types of MC production workflows. We present the operational procedures to optimize the usage of available resources and we the operational model of CMS for including opportunistic resources, such as the larger Tier-3 sites, into the central production operation
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