Cosmic ray antiprotons provide an important probe for the study of the galactic Dark Matter, as they could be produced by exotic sources. On the other hand, antiprotons are anyway produced by ...standard nuclear reactions of cosmic ray nuclei on interstellar matter. This process is responsible for a background flux that must be carefully determined to estimate the detectability of an hypothetical exotic signal. Estimates of this background suffer from potential uncertainties of various origins. The propagation of cosmic antiprotons depends on several physical characteristics of the Galaxy which are poorly known. Antiprotons are created from cosmic protons and helium nuclei whose fluxes were not measured with great accuracy until very recently. Calculations of antiproton fluxes make use of nuclear physics models with their own shortcomings and uncertainties. The goal of this paper is to give a new evaluation of the cosmic antiproton flux along with the associated uncertainties. The propagation parameters were tightly constrained in Maurin et al. 2001 by an analysis of cosmic ray nuclei data in the framework of a two-zone diffusion model and we apply these parameters to the propagation of antiprotons. We use the recently published data on proton and helion fluxes, and we find that this particular source of uncertainty has become negligible. The Monte Carlo program DTUNUC was used to carefully examine nuclear reactions. We find that all the cosmic antiproton fluxes naturally coming out of the calculation are fully compatible with experimental data. Uncertainties in this flux have been strongly reduced. Those related to propagation are less than 25%. All other possible sources of uncertainty have also been studied.
Monte Carlo Production Management at CMS Boudoul, G; Franzoni, G; Norkus, A ...
Journal of physics. Conference series,
01/2015, Letnik:
664, Številka:
7
Journal Article
Recenzirano
Odprti dostop
The analysis of the LHC data at the Compact Muon Solenoid (CMS) experiment requires the production of a large number of simulated events. During the RunI of LHC (20102012), CMS has produced over 12 ...Billion simulated events, organized in approximately sixty different campaigns each emulating specific detector conditions and LHC running conditions (pile up). In order to aggregate the information needed for the configuration and prioritization of the events production, assure the book-keeping of all the processing requests placed by the physics analysis groups, and to interface with the CMS production infrastructure, the web- based service Monte Carlo Management (McM) has been developed and put in production in 2013. McM is based on recent server infrastructure technology (CherryPy + AngularJS) and relies on a CouchDB database back-end. This contribution covers the one and half year of operational experience managing samples of simulated events for CMS, the evolution of its functionalities and the extension of its capability to monitor the status and advancement of the events production.
Primordial black holes (pbhs) have motivated many studies since it was shown that they should evaporate and produce all kinds of particles (Hawking CITE). Recent experimental measurements of cosmic ...rays with great accuracy, theoretical investigations on the possible formation mechanisms and detailed evaporation processes have revived the interest in such astrophysical objects. This article aims to use the latest developments in antiproton propagation models (Maurin et al. CITE; Donato et al. CITE) together with new data from BESS, CAPRICE and AMS experiments to constrain the local amount of pbh dark matter. Depending on the diffusion halo parameters and on the details of the emission mechanisms, we derive an average upper limit of the order of $\rho_{\odot}^{\rm PBH}\approx 1.7\times10^{-33}$g cm-3.
A prototype for the AMS-RICH experiment Boudoul, G.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,
05/2003, Letnik:
504, Številka:
1-3
Journal Article, Conference Proceeding
Recenzirano
The AMS spectrometer will be installed at the International Space Station in 2005. Among other improvements over the first version of the instrument, a ring imaging Cherenkov detector will be added ...and should open a new window for cosmic-ray physics, allowing isotope separation up to A≈25 between 1 and 10GeV/c and element identification up to Z≈25 between threshold and 1TeV/c/nucleon. It should also contribute to the high level of redundancy required for AMS and reject efficiency albedo particles. A second generation prototype has been operated for a few months: the architecture and the first results are presented.
Depending on various assumptions on the energy scale of inflation and assuming a primordial power spectrum of a step‐like structure, we explore new possibilities for Primordial Black Holes (PBH) and ...Planck relics to contribute substantially to Cold Dark Matter in the Universe. A recently proposed possibility to produce Planck relics in four‐dimensional string gravity is considered in this framework. Possible experimental detection of PBHs through gravitational waves is also explored. We stress that inflation with a low energy scale, and also possibly when Planck relics are produced, leads unavoidably to relics originating from PBHs that are not effectively classical during their formation, rendering the usual formalism inadequate for them.
In most cosmological models, primordial black holes (PBHs) should have formed in the early Universe. Their Hawking evaporation into particles could eventually lead to the formation of antideuterium ...nuclei. This paper is devoted to a first computation of this antideuteron flux. The production of these antinuclei is studied with a simple coalescence scheme, and their propagation in the Galaxy is treated with a well-constrained diffusion model. We compare the resulting primary flux to the secondary background, due to the spallation of protons on the interstellar matter. Antideuterons are shown to be a very sensitive probe for primordial black holes in our Galaxy. The next generation of experiments should allow investigators to significantly improve the current upper limit, nor even provide the first evidence of the existence of evaporating black holes.
The CMS Tracker End-Caps integration Boudoul, Gaëlle
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2008, Letnik:
596, Številka:
1
Journal Article
Recenzirano
The two CMS Tracker End-Caps (TECs) consist of nine disks each, totalling 6400 silicon modules mounted on 288 intermediate sub-structures: the “petals”, a carbon fiber plated honeycomb support which ...carries up to 28 modules arranged in seven radial rings. One of the TECs has been integrated at CERN by IPN Lyon, while the second one was assembled in RWTH-Aachen I. This contribution describes in detail the integration procedures, including: the qualification of petals before insertion, the sector by sector (18 petals) mechanical integration inside the TEC structure and the commissioning at room temperature and in the cold at
-
20
∘
. The problems encountered during the whole assembly procedure and their solutions will be reported as well as the final performance of the two TECs. Both are now integrated in the CMS Tracker tube together with the Inner and Outer Barrel part. We will show the noise performance obtained under these conditions.
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