53 research outputs found
Underlying events in p+p collisions at LHC energies
General properties of hadron production are investigated in proton-proton
collisions at LHC energies. We are interested in the characteristics of hadron
production outside the identified jet cones. We improve earlier definitions and
introduce surrounding rings/belts around the cone of identified jets. In this
way even multiple jet events can be studied in details. We define the
underlying event as collected hadrons from outside jet cones and outside
surrounding belts, and investigate the features of these hadrons. We use a
PYTHIA generated data sample of proton-proton collisions at s = (7 TeV)^2. This
data sample is analysed by our new method and the widely applied CDF method.
Angular correlations and momentum distributions have been studied and the
obtained results are compared and discussed.Comment: 5 pages, 5 figures, to appear in the EPJ Web of Conferences,
Proceedings of the International Workshop on Hot and Cold Baryonic Matter
2010 (Budapest, Hungary, 15-20 August 2010
Jets and underlying events at LHC energies
Jet-matter interaction remains a central question and a theoretical challenge in heavy-ion physics and might become important in high-multiplicity events in proton-proton collisions at LHC energies. Full jet measurement at LHC offer the proper tool to investigate energy loss process and fragmentation of hard parton in the medium. Since jet reconstruction will be constrained to small cone sizes, then study of the connection between jets and surrounding environment provides a further possibility to extend our exploration. We study jets at √s = 14 TeV and pp collisions at √s = 7 TeV. We analyze the flavor components in jet-like environments. We introduce a definition for surrounding cones/belts and investigate flavor dependence and correlation of different hadron species produced in jets. Here, we focus on proton-triggered correlations. Our analysis can be extended for heavy ion collisions. © Published under licence by IOP Publishing Ltd
Developments and the preliminary tests of Resistive GEMs manufactured by a screen printing technology
We report promising initial results obtained with new resistive-electrode GEM
(RETGEM) detectors manufactured, for the first time, using screen printing
technology. These new detectors allow one to reach gas gains nearly as high as
with ordinary GEM-like detectors with metallic electrodes; however, due to the
high resistivity of its electrodes the RETGEM, in contrast to ordinary
hole-type detectors, has the advantage of being fully spark protected. We
discovered that RETGEMs can operate stably and at high gains in noble gases and
in other badly quenched gases, such as mixtures of noble gases with air and in
pure air; therefore, a wide range of practical applications, including
dosimetry and detection of dangerous gases, is foreseeable. To promote a better
understanding of RETGEM technology some comparative studies were completed with
metallic-electrode thick GEMs. A primary benefit of these new RETGEMs is that
the screen printing technology is easily accessible to many research
laboratories. This accessibility encourages the possibility to manufacture
these GEM-like detectors with the electrode resistivity easily optimized for
particular experimental or practical applications
Study of GEM-like detectors with resistive electrodes for RICH applications
We have developed prototypes of GEM-like detectors with resistive electrodes
to be used as RICH photodetectors equipped with CsI photocathodes. The main
advantages of these detectors are their intrinsic spark protection and
possibility to operate at high gain (~10E5) in many gases including poorly
quenched ones, allowing for the adoption of windowless configurations in which
the radiator gas is also used in the chamber. Results of systematic studies of
the resistive GEMs combined with CsI photocathodes are presented: its quantum
efficiency, rate characteristics, long-term stability, etc. On the basis of the
obtained results, we believe that the new detector will be a promising
candidate for upgrading the ALICE RICH detectorComment: Presented at the International Workshop RICH-2007, Trieste, Italy,
October 200
VHMPID: a new detector for the ALICE experiment at LHC
This article presents the basic idea of VHMPID, an upgrade detector for the
ALICE experiment at LHC, CERN. The main goal of this detector is to extend the
particle identification capabilities of ALICE to give more insight into the
evolution of the hot and dense matter created in Pb-Pb collisions. Starting
from the physics motivations and working principles the challenges and current
status of development is detailed.Comment: 4 pages, 6 figures. To be published in EPJ Web of Conference
Cryptocapsinepoxide-type Carotenoids from Red Mamey, Pouteria sapota
Three new carotenoids, cryptocapsin-5,6-epoxide, 3ʹ-deoxycapsanthin-5,6-epoxide, and cryptocapsin-5,8-epoxides, have been isolated from the ripe fruits of red mamey (Pouteria sapota). Cryptocapsin-5,6-epoxide was prepared by partial synthesis via epoxidation of cryptocapsin and the (5R,6S)- and (5S,6R)-stereoisomers were identified by HPLC-ECD analysis. Spectroscopic data of the natural (anti) and semisynthetic (syn) derivatives obtained by acid-catalyzed rearrangement of cryptocapsin-5,8-epoxide stereoisomers were compared for structural elucidation. Chiral HPLC separation of natural and semisynthetic samples of cryptocapsin-5,8-epoxides was performed and HPLC-ECD analysis allowed configurational assignment of the separated stereoisomers
Status of the mid-IR ELT imager and spectrograph (METIS)
The Mid-Infrared ELT Imager and Spectrograph (METIS) is one of three first light instruments on the ELT. It will provide high-contrast imaging and medium resolution, slit-spectroscopy from 3 - 19um, as well as high resolution (R ∼ 100,000) integral field spectroscopy from 2.9-5.3μm. All modes observe at the diffraction limit of the ELT, by means of adaptive optics, yielding angular resolutions of a few tens of milliarcseconds. The range of METIS science is broad, from Solar System objects to active galactic nuclei (AGN). We will present an update on the main science drivers for METIS: circum-stellar disks and exoplanets. The METIS project is now in full steam, approaching its preliminary design review (PDR) in 2018. In this paper we will present the current status of its optical, mechanical and thermal design as well as operational aspects. We will also discuss the challenges of building an instrument for the ELT, and the required technologies. © 2018 SPIE
Mid-infrared circumstellar emission of the long-period Cepheid l Carinae resolved with VLTI/MATISSE
Stars and planetary system
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