C. Santamarina Ríos
A5082486927- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Particle Detector Development and Performance
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Black Holes and Theoretical Physics
- Computational Physics and Python Applications
- Particle Accelerators and Free-Electron Lasers
- Medical Imaging Techniques and Applications
- Atomic and Subatomic Physics Research
- Distributed and Parallel Computing Systems
- Superconducting Materials and Applications
- Cosmology and Gravitation Theories
- Nuclear physics research studies
- Radiation Detection and Scintillator Technologies
- Advanced Data Storage Technologies
- Stochastic processes and statistical mechanics
- Astrophysics and Cosmic Phenomena
- advanced mathematical theories
- Particle accelerators and beam dynamics
- International Science and Diplomacy
- Advanced NMR Techniques and Applications
- Muon and positron interactions and applications
- Markov Chains and Monte Carlo Methods
Universidade de Santiago de Compostela
2016-2025
Universitat de València
2023
Instituto de Física Corpuscular
2023
European Organization for Nuclear Research
2004-2021
McGill University
1992-2020
Central China Normal University
2020
Institute of High Energy Physics
2020
University of Chinese Academy of Sciences
2020
Tsinghua University
2020
Peking University
2020
The goal of the DIRAC experiment at CERN (PS212) is to measure $\pi^+\pi^-$ atom lifetime with 10% precision. Such a measurement would yield precision 5% on value $S$-wave $\pi\pi$ scattering lengths combination $|a_0-a_2|$. Based part collected data we present first result lifetime, $\tau=[2.91 ^{+0.49}_{-0.62}]\times 10^{-15}$ s, and discuss major systematic errors. This corresponds $|a_0-a_2|=0.264 ^{+0.033}_{-0.020} m_{\pi}^{-1}$.
The DIRAC experiment at CERN has achieved a sizeable production of $\pi^+\pi^-$ atoms and significantly improved the precision on its lifetime determination. From sample 21227 atomic pairs, 4% measurement S-wave $\pi\pi$ scattering length difference $|a_0-a_2| = (.0.2533^{+0.0080}_{-0.0078}|_\mathrm{stat}.{}^{+0.0078}_{-0.0073}|_\mathrm{syst})M_{\pi^+}^{-1}$ been attained, providing an important test Chiral Perturbation Theory.
The goal of the DIRAC experiment at CERN is to measure with high precision lifetime π + -atom (A 2π ), which order 3×10 -15 s, and thus determine s-wave ππ-scattering lengths difference |a 0 -a 2 |.A atoms are detected through characteristic features -pairs from atom break-up (ionization) in target.We report on a first statistics atomic data sample obtained p Ni interactions 24 GeV/c proton momentum present methods separate signal background.
Chiral perturbation theory predicts the lifetime of pionium, a hydrogen-like π+π− atom, to better than 3% precision. The goal DIRAC experiment at CERN is obtain and check this value experimentally by measuring break-up probability pionium in target. In order accurately measure one needs know relationship between 1% accuracy. We have obtained dependence modelling evolution pionic atoms target using Monte Carlo methods. model relies on computation pionium–target-atom interaction cross...
The Event Filter (EF) selection stage is a fundamental component of the ATLAS Trigger and Data Acquisition architecture. Its primary function reduction data flow rate to values acceptable by mass storage operations subsequent offline reconstruction analysis steps. computing instrument EF organized as set independent subfarms, each connected one output Builder (EB) switch fabric. Each subfarm comprises number processors analyzing several complete events in parallel. This paper describes...
The ATLAS experiment at the Large Hadron Collider (LHC) will face challenge of efficiently selecting interesting candidate events in pp collisions 14 TeV center-of-mass energy, whilst rejecting enormous number background events. High-Level Trigger (HLT=second level trigger and Event Filter), which is a software based need to reduce level-1 output rate ap75 kHz ap200 Hz written out mass storage. In this talk an overview current physics system performance HLT selection for electrons photons...
The ATLAS collaboration at CERN operated a combined test beam (CTB) from May until November 2004. prototype of data acquisition system (DAQ) was used to integrate other subsystems into common CTB setup. Data were collected synchronously all the detectors, which represented nine different detector technologies. Electronics and software first level trigger Event selection algorithms high integrated with tested real data. possibility operate remote Filter farm synchronized Trigger Acquisition...
The ATLAS combined test beam in the second half of 2004 saw first deployment High-Level Trigger (HLT). next steps are on pre-series farms experimental area during 2005, commissioning and cosmics tests with full detector 2006 collisions 2007. This paper reviews experience gained beam, describes current status discusses further enhancements to be made. We address issues related dataflow, integration selection algorithms, testing, software distribution, installation improvements.
One of the primary goals Large Hadron Collider is to understand electroweak symmetry breaking mechanism. In Standard Model, described by Higgs mechanism which includes a scalar boson. Electroweak measurements constrain Model boson mass be in 114.4 157 GeV/c^2 range. Within this window, predominantly decays into two b-quarks. As such, we investigate prospect observing decaying b\bar{b} produced weak-boson-fusion with an associated central photon. An isolated, high pt, photon trigger expected...
The hydrogen atom perturbed by a constant 1-dimensional weak quadratic potential $\lambda z^2$ is solved at first-order perturbation theory using the eigenstates of total angular momentum operator - coupled basis. Physical applications this result could be found, for example, in study Zeeman effect weaker than fine-structure effects, or caused instantaneous generalised van der Waals interactions.
Em 1985, acabava oficialmente uma ditadura militar que vigorou no Brasil por mais de vinte anos, e após, se iniciou um processo justiça transição para lidar com a mudança regime ditatorial-autoritário retomada da democracia. Um mecanismo previsto dentro literatura internacional sobre transicional, foi fortemente demandada setores movimentos direitos humanos, familiares, ex-atingidos, é o comissões verdade. Sancionada em 2011 iniciada 2012, Comissão Nacional Verdade propôs investigar as...
During the runtime of any experiment, a central monitoring system that detects problems as soon they appear has an essential role. In large like ATLAS, online data acquisition is distributed across nodes farms, each them running several processes analyse fraction events. this architecture, it necessary to have process collects all from different nodes, produces full statistics histograms and analyses them. paper we present design such system, called gatherer. It allows collect object,...
The evolution of pionium, the $\pi^+ \pi^-$ hydrogen-like atom, while passing through matter is solved within density matrix formalism in first Born approximation. We compare influence on pionium break-up probability between standard probabilistic calculations and more precise picture accounting for interference effects. focus our general result particular conditions DIRAC experiment at CERN.
To cope with the 40 MHz event production rate of LHC, trigger ATLAS experiment selects events in three sequential steps increasing complexity and accuracy whose final results are close to offline reconstruction. The Level-1, implemented custom hardware, identifies physics objects within Regions Interests operates a first reduction 75 kHz. higher levels, Level-2 Level-3, provide software based selection which further reduces about 100 Hz. This paper presents algorithm (/spl mu/Fast) employed...
Abstract The hydrogen atom perturbed by a constant 1-dimensional weak quadratic potential λz 2 is solved at first-order perturbation theory using the eigenstates of total angular momentum operator - coupled basis. Physical applications this result could be found, for example, in study Zeeman effect weaker than fine-structure effects, or caused instantaneous generalised van der Waals interactions.
Pregnancy is characterized by progressive water and sodium accumulation increases in renal blood flow (RBF) glomerular filtration rate (GFR). However, the influence of different nephron segments on increased tubular reabsorption controversial. Consequently, four nonpregnant five pregnant sheep were studied, after chronic instrumentation, to assess salt proximal distal tubules under basal volume-loaded conditions. Lithium clearance was used as a marker for reabsorption. Volume loading...
We present the prospects for discovery of a Standard Model Higgs boson decaying to $b\bar{b}$ pair through Vector Boson Fusion mechanism in association with central photon at Large Hadron Collider (LHC). The provides clean trigger and several advantages despite fact that cross section decreases by approximately factor $α_{em}$. After applying various optimized selection criteria, we obtain significance $\sim$1.9 using ALPGEN interfaced PYTHIA. expected $b$-jet efficiency fake rates other...
ATLAS is one of the four LHC experiments that will start data taking in 2007, designed to cover a wide range physics topics. The trigger system has cope with rate 40 MHz and 23 interactions per bunch crossing. It divided three different levels. first (hardware based) provides signature confirmed by following levels (software running sequence algorithms validating signal step step, looking only region space indicated level (seeding). In this presentation, performance these sequences run at...
The ATLAS combined test beam in the second half of 2004 saw first deployment high-level triggers (HLT). next steps are on pre-series farms experimental area during 2005, commissioning and cosmics tests 2006 collisions 2007. This paper reviews experience gained beam, describes current status discusses further enhancements to be made. We address issues related dataflow, selection algorithms, testing, software distribution, installation improvements