Search results for "method."

Search for a Dark Leptophilic Scalar in e(+) e(-) Collisions

2020

Many scenarios of physics beyond the standard model predict the existence of new gauge singlets, which might be substantially lighter than the weak scale. The experimental constraints on additional scalars with masses in the MeV to GeV range could be significantly weakened if they interact predominantly with leptons rather than quarks. At an e+e- collider, such a leptophilic scalar (φL) would be produced predominantly through radiation from a τ lepton. We report herein a search for e+e-→τ+τ-φL, φL→ℓ+ℓ- (ℓ=e, μ) using data collected by the BABAR experiment at SLAC. No significant signal is observed, and we set limits on the φL coupling to leptons in the range 0.04<mφL<7.0 GeV. These bounds s…

Particle identification in ALICE: a Bayesian approach

2016

We present a Bayesian approach to particle identification (PID) within the ALICE experiment. The aim is to more effectively combine the particle identification capabilities of its various detectors. After a brief explanation of the adopted methodology and formalism, the performance of the Bayesian PID approach for charged pions, kaons and protons in the central barrel of ALICE is studied. PID is performed via measurements of specific energy loss ($\mathrm{d}E/\mathrm{d}x$) and time-of-flight. PID efficiencies and misidentification probabilities are extracted and compared with Monte Carlo simulations using high-purity samples of identified particles in the decay channels ${\rm K}^0_S \righta…

Calibration of the photon spectrometer PHOS of the ALICE experiment

2019

Journal of Instrumentation 14(05), P05025 - P05025 (2019). doi:10.1088/1748-0221/14/05/P05025

Study of cosmic ray events with high muon multiplicity using the ALICE detector at the CERN Large Hadron Collider

2016

ALICE is one of four large experiments at the CERN Large Hadron Collider near Geneva, specially designed to study particle production in ultra-relativistic heavy-ion collisions. Located 52 meters underground with 28 meters of overburden rock, it has also been used to detect muons produced by cosmic ray interactions in the upper atmosphere. In this paper, we present the multiplicity distribution of these atmospheric muons and its comparison with Monte Carlo simulations. This analysis exploits the large size and excellent tracking capability of the ALICE Time Projection Chamber. A special emphasis is given to the study of high multiplicity events containing more than 100 reconstructed muons a…

Visibilidad internacional de la investigación de la Universitat de València (Web of Science 2000-2009)

2013

En esta publicación se ofrecen los primeros resultados del análisis de la producción científica de la Universitat de València para la década 2000-2009 realizado mediante la explotación de las bases de datos de la Web of Science (SCI, SSCI y A&HCI). La información está organizada en dos capítulos. El primero, dedicado a ofrecer una imagen general de la producción de la Universitat, permite apreciar el volumen de publicaciones circulantes en esas bases de datos, su crecimiento en el periodo estudiado, la tipología documental, el idioma de publicación y su clasificación temática. Para esto se han utilizado dos clasificaciones, la primera más detallada basada en las 247 categorías temáticas en …

Mathematical Methods for Research Excellence: Book of Abstracts 79th International Scientific Conference University of Latvia

2021

Color constancy in dermatoscopy with smartphone

2017

The recent spread of cheap dermatoscopes for smartphones can empower patients to acquire images of skin lesions on their own and send them to dermatologists. Since images are acquired by different smartphone cameras under unique illumination conditions, the variability in colors is expected. Therefore, the mobile dermatoscopic systems should be calibrated in order to ensure the color constancy in skin images. In this study, we have tested a dermatoscope DermLite DL1 basic, attached to Samsung Galaxy S4 smartphone. Under the controlled conditions, jpeg images of standard color patches were acquired and a model between an unknown device-dependent RGB and a device independent Lab color space h…

Studies of the performance of the ATLAS detector using cosmic-ray muons

2011

Muons from cosmic-ray interactions in the atmosphere provide a high-statistics source of particles that can be used to study the performance and calibration of the ATLAS detector. Cosmic-ray muons can penetrate to the cavern and deposit energy in all detector subsystems. Such events have played an important role in the commissioning of the detector since the start of the installation phase in 2005 and were particularly important for understanding the detector performance in the time prior to the arrival of the first LHC beams. Global cosmic-ray runs were undertaken in both 2008 and 2009 and these data have been used through to the early phases of collision data-taking as a tool for calibrat…

Measurement of inclusive jet and dijet cross sections in proton-proton collisions at 7 TeV centre-of-mass energy with the ATLAS detector

2011

Jet cross sections have been measured for the first time in proton-proton collisions at a centre-of-mass energy of 7 TeV using the ATLAS detector. The measurement uses an integrated luminosity of 17 nb−1 recorded at the Large Hadron Collider. The anti-k t algorithm is used to identify jets, with two jet resolution parameters, R=0.4 and 0.6. The dominant uncertainty comes from the jet energy scale, which is determined to within 7% for central jets above 60 GeV transverse momentum. Inclusive single-jet differential cross sections are presented as functions of jet transverse momentum and rapidity. Dijet cross sections are presented as functions of dijet mass and the angular variable χ. The res…

Measurements of underlying-event properties using neutral and charged particles in pp collisions at root s=900 GeV and root s=7 TeV with the ATLAS de…

2011

We present first measurements of charged and neutral particle-flow correlations in pp collisions using the ATLAS calorimeters. Data were collected in 2009 and 2010 at centre-of-mass energies of 900 GeV and 7 TeV. Events were selected using a minimum-bias trigger which required a charged particle in scintillation counters on either side of the interaction point. Particle flows, sensitive to the underlying event, are measured using clusters of energy in the ATLAS calorimeters, taking advantage of their fine granularity. No Monte Carlo generator used in this analysis can accurately describe the measurements. The results are independent of those based on charged particles measured by the ATLAS …