Prochains séminaires


24 juin 2024
A new extragalactic CMB foreground. Large scale anomalies and the Cold spot.
Diego García Lambas (Universidad Nacional de Córdoba, Argentina)
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Description :
In this talk I will briefly review the serendipitous discovery of a new extragalactic foreground associated with nearby Spiral galaxies and its effect on the Cosmic Microwave Background as well as current ongoing work. In recent papers we have analysed the presence of a systematic decrease in CMB temperatures around nearby large spiral galaxies pointing to an unknown interaction with CMB photons extending to megaparsec scales around these galaxies. Temperature model maps based on nearby galaxies and the Planck CMB map have a remarkable resemblance. Compared to 1000 simulated LCDM  maps, we find  none of them showing such a strong correlation with the foreground map over both large and small angular scales.  In particular, the quadrupole, octopole, and ℓ = 4 and ℓ = 5 modes correlate with the foreground map to a high significance.  The explanation of the largely non-gaussian CMB Cold Spot feature with this model will be particularly discussed. Also I will show new evidence and other possible impacts on our current cosmological scenario.
 
Début :
lundi 24 juin 2024 à 14:00:00 heure d’été d’Europe centrale
Fin :
lundi 24 juin 2024 à 16:00:00 heure d’été d’Europe centrale
Endroit :
CPPM (Amphitheatre)
1 juil. 2024
Exploring the unknown side of the B-meson decays at Belle II
Valerio Bertacchi (Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France)
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Description :

Abstract: Our knowledge of $B$-meson decays to hadrons is limited, and about 40% of the total $B$ width is not known in terms of exclusive branching fractions. Therefore, the unmeasured decays are usually simulated with relevant assumptions and coarse approximations for the description of the dynamics, as in the PYTHIA fragmentation model. This limits the capability of understanding and controlling the backgrounds of many $B$-decay analyses. A large part of the Belle II experiment physics program relies on the so-called $B$-tagging, i.e. identifying the partner $B$ meson produced in association with the signal $B$ meson to infer the properties of the signal. The impact of our limited knowledge of hadronic $B$ decays on $B$-tagging and Belle II measurements in general are discussed in this seminar. The Belle II collaboration is doing a great effort to mitigate the problem, studying new high-purity hadronic $B$ decay channels. The unknown fraction of the total $B$ width is spread across multiple exclusive channels, therefore improvements are not expected from single results, but require the systematic exploration of a significant fraction of them. This effort is presented, with a particular attention to the recent $\overline B\to D^{(*)} K^- K^{(*)0}_{(S)}$ and $B^-\to D^0\rho(770)^-$ Belle II measurements.

Début :
lundi 1 juillet 2024 à 14:00:00 heure d’été d’Europe centrale
Fin :
lundi 1 juillet 2024 à 15:30:00 heure d’été d’Europe centrale
16 sept. 2024
Sustainable Cherenkov Detectors and Cooling Systems
Gregory Hallewell (Centre de Physique des Particules de Marseille)
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Début :
lundi 16 septembre 2024 à 14:00:00 heure d’été d’Europe centrale
Fin :
lundi 16 septembre 2024 à 15:30:00 heure d’été d’Europe centrale
7 oct. 2024
Physics at ISOLDE
Sean Freeman (CERN/The University of Manchester)
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Début :
lundi 7 octobre 2024 à 14:00:00 heure d’été d’Europe centrale
Fin :
lundi 7 octobre 2024 à 15:30:00 heure d’été d’Europe centrale

5 derniers séminaires


17 juin 2024
L'ITK-Pixels, le nouveau détecteur à pixels d'ATLAS pour HL-LHC
Eric Vigeolas (CPPM)
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Description :

La construction du détecteur à pixels du nouveau trajectographe d'ATLAS, le ITK,  a commencé. Ce séminaire vous donnera un aperçu de 10 années de travail pour construire le plus gros trajectographe en Silicium jamais installé sur un accélérateur. Nous aborderons les difficultés et les défis à vaincre pour parvenir à concevoir et à fabriquer un tel objet. Un tour des activités qui auront lieu dans le laboratoire durant les deux prochaines années vous sera proposé, afin de vous expliquer ce que les équipes du CPPM vont réaliser.

 

Début :
lundi 17 juin 2024 à 14:00:00 heure d’été d’Europe centrale
Fin :
lundi 17 juin 2024 à 15:30:00 heure d’été d’Europe centrale
10 juin 2024
Expected Performance of the ATLAS Phase II Inner Tracker
Thomas Strebler (CPPM, Aix-Marseille Université, CNRS/IN2P3 (FR))
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Description :
The upgrade to the High-Luminosity LHC (HL-LHC), with its increase to 140-200 proton-proton collisions per bunch crossing, poses formidable challenges for track reconstruction. The Inner Tracker (ITk) is a silicon-only replacement of the current ATLAS tracking system as part of its Phase-II upgrade, designed to meet the challenges and continue to deliver high-performance track reconstruction. This seminar will give an overview of the expected performance of tracking and its impact on higher level objects. The ITk most recent layout optimisation and developments, and their impact on tracking performance, will also be reviewed.
 
Début :
lundi 10 juin 2024 à 14:00:00 heure d’été d’Europe centrale
Fin :
lundi 10 juin 2024 à 15:30:00 heure d’été d’Europe centrale
3 juin 2024
Pevatrons with CTAO: Study of the Boomerang SNR in the LST-1 era
Gabriel Emery (CPPM)
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Description :

The quest for PeVatrons, sources of galactic cosmic rays accelerated up to PeV energies, saw an exciting development in the last years, thanks to the many gamma-ray sources detected by ground array experiments at energy above 100 TeV. Among those sources, the supernova remnant SNR G106.3+2.7 (including the Boomerang PWN) is a promising PeVatron candidate for which the ultra-high energy emission can be explained with both hadronic and leptonic emission scenarios. It was detected with a very high significance detection above 100 TeV by LHAASO, making it a candidate for the emission of PeV protons.
Imaging Atmospheric Cherenkov Telescopes (IACTs) are ideal instruments to investigate the nature of the most energetic sources of the Universe in gamma-ray astronomy thanks to their optimal angular and energy resolution. The Cherenkov Telescope Array Observatory (CTAO) will be the leading instrument for observations between tens of GeV and hundreds of TeV thanks to an hybrid array of IACTs. It will allow for high resolution observation of the TeV sky in a complementary energy range with LHAASO. Using the LST-1, the Large-Sized Telescope prototype of the Cherenkov Telescope Array Observatory, together with the two neighbors IACTs of the MAGIC experiment, we are currently observing the SNR G106.3+2.7 at Large Zenith Angle (LZA), which allows us to explore the 1-50 TeV region of the energy spectrum.
I will give an overview of the CTAO and its first telescope, the LST-1. Then I will describe the status of the knowledge on galactic PeVatrons and present the work lead by CPPM on the observation of the SNR G106.3+2.7 with LST-1 and MAGIC.

Début :
lundi 3 juin 2024 à 14:00:00 heure d’été d’Europe centrale
Fin :
lundi 3 juin 2024 à 15:30:00 heure d’été d’Europe centrale
27 mai 2024
Optically Pumped Magnetometers for recording brain activity with high spatial and temporal resolution
Jean-Michel Badier (INSERM)
Christian Bénar (INSERM)
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Description :

Magnetoencephalography (MEG) and electroencephalography (EEG) is electrophysiological techniques for recording brain activity at its time-scale of function, i.e., at the millisecond level. An inverse problem can be applied to EEG and MEG in order to estimate the actual location of sources within the brain from the surface measurements. Contrary to EEG, MEG is little influenced by the low electrical conductivity of the skull, which severely blurs EEG electrical fields. In practice, this leads to better spatial capacities for MEG. MEG is used in presurgical evaluation of epilepsy and in fundamental neuroscience.

Classical MEG sensors (SQUIDs) relies on supraconductivity, which is a heavy constraint. Recently, new sensors have been developed for MEG, the Optically Pumped magnetometers. In this talk, we will review the potential capacities of these new sensors and show initial results of combined recordings of OPM and intracerebral EEG performed at the INS. We will also present the industrial chair project NewMeg funded by Amidex.

Début :
lundi 27 mai 2024 à 14:00:00 heure d’été d’Europe centrale
Fin :
lundi 27 mai 2024 à 15:30:00 heure d’été d’Europe centrale
6 mai 2024
Status of the Euclid mission in flight
William Gillard (CPPM - Université Aix-Marseille)
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Description :

Euclid is an ESA mission aiming at studying the geometry and nature of the dark Universe. Over a span of six years, Euclid will meticulously survey nearly 15,000 square degrees of the extragalactic sky. Equipped with optical capabilities spanning from 530 to 920 nanometers and near-infrared imaging in Y, J, and H bands, as well as slitless spectroscopy ranging from 1206 to 1892 nanometers, Euclid will capture detailed data on distant galaxies between redshift of 0.84 and 2. Launched successfully on July 1, 2023, Euclid was placed in orbit around the second Lagrange point where both of its cutting-edge instruments, the VIS and the NISP, underwent meticulous commissioning and calibration over the initial six months of the mission. As the Euclid survey commenced in February 2024, this presentation will provide insights into the mission's status at Lagrange 2 and showcase the initial scientific images and results captured by both instruments.

Début :
lundi 6 mai 2024 à 14:00:00 heure d’été d’Europe centrale
Fin :
lundi 6 mai 2024 à 15:30:00 heure d’été d’Europe centrale