Measurement of low-energy cosmic-ray electron and positron spectra at 1 AU with the AESOP-Lite spectrometer

We report on a new measurement of the cosmic ray (CR) electron and positron spectra in the energy range of 20 MeV -- 1 GeV. The data were taken during the first flight of the balloon-borne spectrometer AESOP-Lite (Anti Electron Sub Orbital Payload), which was flown from Esrange, Sweden, to Ellesmere Island, Canada, in May 2018. The instrument accumulated over 130 hours of exposure at an average altitude of 3 g.cm$^{-2}$ of residual atmosphere. The experiment uses a gas Cherenkov detector and a magnetic spectrometer, consisting of a permanent dipole magnet and silicon strip detectors (SSDs), to identify particle type and measure the rigidity. Electrons and positrons were detected against a background of protons and atmospheric secondary particles. The primary cosmic ray spectra of electrons and positrons, as well as the re-entrant albedo fluxes, were extracted between 20 MeV -- 1 GeV during a positive solar magnetic polarity epoch. The positron fraction below 100 MeV appears flat, suggesting diffusion dominated solar modulation at low rigidity. The all-electron spectrum is presented and compared with models from a heliospheric numerical transport code.Comment: 21 pages, 13 figure

Mise en service du calorimetre electromagnetique d'Atlas et determination du potentiel de decouverte d'un Z' --> e+e- dans les premieres donnees LHC

After about fifteen years of development, the ATLAS detector is ready to operate and recorded, in 2008, several millions of cosmic events as well as first LHC data. This achievement is based on the long experience of beam tests and on the large effort towards the detector in situ commissioning undertaken by the ATLAS collaboration. This promises fast ability to perform searches for evidence of Higgs boson and new physics. I heavily contributed to the in situ commissioning of the EM calorimeter. To verify its performance, I studied the first cosmic data taken in 2006 which allowed the first in situ analysis of dead channels, energy reconstruction and detector response uniformity. This participation to the commissioning has continued with the study of the single beam data recorded during the first week of LHC operation (Sept. 2008). Expanding on my expertise of the EM calorimeter, I focused my physics analysis, prepared with simulation, on the promising discovery potential of new physics at LHC via the di-electron/di-photon decay of new heavy gauge boson in the early LHC data (the first 100 pb-1). Possible limitations coming from early hardware problems or imperfect electron energy calibration in first data have been estimated. According to the new schedule of LHC operation, this analysis will be possible with 10 TeV pp collisions data in 2010

Mise en service du calorimetre<br />electromagnetique d'Atlas<br />et determination du potentiel de decouverte<br />d'un Z' --> e+e- dans les premieres donnees LHC

After about fifteen years of development, the ATLAS detector is ready to operate and recorded, in 2008, several millions of cosmic events as well as first LHC data. This achievement is based on the long experience of beam tests and on the large effort towards the detector in situ commissioning undertaken by the ATLAS collaboration. This promises fast ability to perform searches for evidence of Higgs boson and new physics. I heavily contributed to the in situ commissioning of the EM calorimeter. To verify its performance, I studied the first cosmic data taken in 2006 which allowed the first in situ analysis of dead channels, energy reconstruction and detector response uniformity. This participation to the commissioning has continued with the study of the single beam data recorded during the first week of LHC operation (Sept. 2008). Expanding on my expertise of the EM calorimeter, I focused my physics analysis, prepared with simulation, on the promising discovery potential of new physics at LHC via the di-electron/di-photon decay of new heavy gauge boson in the early LHC data (the first 100 pb-1). Possible limitations coming from early hardware problems or imperfect electron energy calibration in first data have been estimated. According to the new schedule of LHC operation, this analysis will be possible with 10 TeV pp collisions data in 2010.Apres une quinzaine d'annees de developpement, le detecteur Atlas est operationnel. Fin 2008, il enregistra plusieurs millions d'´evenements cosmiques ainsi les premieres donnees à un faisceau LHC. Cette reussite est le resultat d'une longue strategie de tests sous faisceau et des efforts menes par la collaboration lors de la mise en service dans la caverne du detecteur. Une exploitation rapide et fiable des premieres donnees pour la recherche du boson de Higgs et de nouvelle physique est donc attendue. J'ai contribue significativement à la mise en service du calorim`etre ´electromagn´etique (EM). Je me suis interesse à l'´etude de la reponse de ce sous d´etecteur aux muons cosmiques. Ces premieres donnees ont permis de rechercher des canaux morts, de tester la reconstruction de l'´energie ainsi que l'uniformite spatiale de la reponse du detecteur. Ma participation à cette mise en service s'est poursuivie par l'´etude des donnees acquises à l'aide d'un seul faisceau lors du demarrage du LHC (Sept. 2008). L'expertise du calorimetre EM acquise m'a ensuite permis d'etudier l'impact de la qualite des premieres donnees du LHC sur le potentiel de decouverte d'un Z' --> e+e-. Les limites induites par de possibles problemes hardware ou d'etalonnage en énergie ont été estinees. Etant donne le nouvel agenda du LHC, cette analyse sera possible avec les collisions pp à 10 TeV de 2010

Mise en service du calorimètre électromagnétique d'Atlas et détermination du potentiel de découverte d'un Z' -> e+e- dans les premières données LHC

J'ai réalisé ma thèse au sein d'un groupe Atlas au Centre de Physique des Particules de Marseille à l'Université d'Aix-Marseille. Durant les deux années précédant le démarage du LHC, de grands efforts dans la mise en service du détecteur ont été menés par la collaboration Atlas. j'ai contribué à la mise en service du calorimètre électromagnétique (EM). Je me suis intéressé à l'étude de sa réponse aux muons cosmiques. Cers premières données ont permis de rechercher des acanaux morts, de tester la reconstruction de l'énergie ainsi que l'uniformité spatiale de la réponse du détecteur. Ma participation à cette mise en service s'est poursuivie par l'étude des doonées acquides à l'aide d'un seul faisceau lors du démarrage du LHC (Sept. 2008). La compréhensio du détecteur en opération est cruciale pour la recherche de nouvelle physique. L'expertise du calorimètre EM acquise m'a permis d'étudier l'impact de la qualité des premières données LHC sur le potientiel de découverte d'un Z' -> e+eI have prepared my PhD within ATLAS group of the CEnter of Particule Physics of Marseille at the Aix-Marseille University. For two years before the star-up of the LHC, a large effort towards the detector commissioning was understaken by the ATLAS collaboration. I contributes to the commissioning of the electromagnetic (EM) calorimeter. To verify its performance, I studied the first cosmic data taken in 2006 which allowed the first in situ analysis of dead channels, energy reconstruction and detector response uniformity. this participation to the commissioning has continued with the study of the single beam data recorded during the first week of LHC operation (sept. 2008). The understanding of the detector in operation is crucial in the search for evidence of new physics. Expanding on my expertise of the EM calorimeter, I have focused my physices analysis on the promising discovery potential of new physics at LHC via the di-electron decay of a heavy gauge boson in the early LHC dataAIX-MARSEILLE2-BU Sci.Luminy (130552106) / SudocSudocFranceF