Séminaire de physique corpusculaire

Le séminaire de DPNC tient lieu le mercredi a 17.00 heures (chaques deux semaines) dans l'auditoire Stückelberg

Semestre d'été 2000-2001

 28 Mar. 2001 Dr. L. Malgeri, DPNC Université de Genève moved to 11 Avr 2001 4 Avr. 2001 Dr. V. Plyaskin, ITEP Moscow Calculation of atmospheric neutrino flux 11 Avr. 2001 Dr. L. Malgeri, DPNC Université de Genève FAST: a proposal for a high precision muon lifetime (and $G_F$) measurement. 25 Avr. 2001 Dr. M. Donega, DPNC Université de Geneve La mesure des oscillations de neutrions: est-ce possible avec un faisceau de basse energie? 9 Mai. 2001 Dr. P. Petroff, LAL Orsay Is the Tevatron able to discover a light Higgs and SUSY before the LHC ? 16 Mai. 2001 Dr. Dario Crosetto Saving lives through early detection: Breaking the PET efficiency barrier with the 3D-CBS 23 Mai 2001 Dr. Paul G. Seiler PSI Precision Radiotherapy of Cancer 30 Mai 2001 Dr. C. Lacasta, IFIC-U. Valencia Compton Aperture Imaging in Nuclear Medicine: First results with a Si pad detector and possible applications. 6 Juin 2001 Dr. Eric Lancon, CEA-Saclay Mesure de la masse du boson W au LEP. 13 Juin 2001 Silvia Borghi, DPNC Universite de Geneve moved to next autumnLa mise en route de l'experience HARP

Dr. L. Malgeri, DPNC Université de Genève: FAST: a proposal for a high precision muon lifetime (and $G_F$) measurement.

$G_F$ is one of the fundamental constants of the Standard Model of Electroweak interactions. Its value is directly derived, and hence limited, by the measurements of the muon lifetime whose latest and most precise determinations are almost twenty years old. FAST will be a small experiment located on the pion beam in PSI and based on a high resolution imaging detector in order to keep systematic effects under control. It will allow to increase the accuracy on the muon lifetime by more than an order of magnitude and therefore to reach the 1~ppm level for $G_F$. In order to reach the design goals, a very high statistics of $10^{12} \; \pi^+ \rightarrow \mu^+ \nu_\mu \rightarrow \mathrm{e^+} \nu_\mathrm{e} \bar \nu_\mu \nu_\mu$ full decay chains have to be analysed at a very high trigger rate of 1~MHz. These figures make the experiment also a challenging test-bench for new generation DAQ systems.
Transparencies: .ps

Dr. V. Plyaskin, ITEP Moscow: Calculation of atmospheric neutrino flux

A calculation of the fluxes of primary particles arriving to the Earth's vicinity as well as those produced in the interactions of the primaries with the atmosphere is presented. The result of calculations is compared with the experimental data obtained with the Alpha Magnetic Spectrometer (AMS). A good agreement of calculated and measured fluxes of charged particles supports the viability of the atmospheric neutrino flux calculation.
Transparencies: .ps

Dr. M. Donega, DPNC Université de Genève: La mesure des oscillations de neutrions: est-ce possible avec un faisceau de basse energie?

The analysis of the low energy neutrino superbeam from SPL 2.2 GeV protons is presented. The proposed beam is used to study neutrino oscillations with a 40 kton detector at 130 km. The analysis of the sensitivity on the oscillation parameter theta13 is performed. The comparison with the actual experiments shows an improvement of more than one order of magnitude in sensitivity."

P. Petroff, LAL Orsay: Is the Tevatron able to discover a light Higgs and SUSY before the LHC?

The LEP hints seems to indicate a light Higgs at 115 Gev and the last g-2 results suggests light SUSY masses. Does it mean that both the Higgs and SUSY could be within of reach of the Tevatron experiments ? The Run II has started on the 1rst of March. We shall report on the status of the machine and on the D0 detector. The very rich physics program will be presented with the emphasis on the potential for light Higgs and SUSY discovery.
Transparencies: .ppt

Dr. D. Crosetto: Saving lives through early detection: Breaking the PET efficiency barrier with the 3D-CBS

An innovative medical imaging 3-D Complete-Body-Scan (3D-CBS) device, combining the benefits of functional imaging capability of the Positron Emission Tomography (PET) and anatomical imaging capability of the Computed Tomography (CT) is presented. The unique architecture of the 3D-CBS electronics allows for the extension of the axial field of view to over one meter in length. The 3D-CBS captures about 1000 out of 10000 photons in time coincidence, compared to only 2 out of 10000 captured by the best current PET. In addition the overall architecture of the 3D-CBS permits the use of a single detection apparatus without moving the patient or the detector during a whole body scan and featuring significant improvements in the scanning speed by providing PET and CT exams combined in 2-4 minutes.
Transparencies: .pdf

Dr. P. Seiler, Paul Scherrer Institute: Precision Radiotherapy of Cancer

Using advanced methods of medical physics, precision radiotherapy creates a volume of high tumoricidal dose in the patient's body that matches very precisely in three dimensions the form of the tumor (conformal radiotherapy). Today, this can be used for the treatment of motionless tumors. However, organ movement - especially in the chest and in the abdomen - impedes the overall application. Different modalities of conformal radiotherapy will be described with emphasis on recent achievements in proton therapy at PSI. A novel development for the real time tracking of moving tumors will be presented.

C. Lacasta, IFIC-U. Valencia: Compton Aperture Imaging in Nuclear Medicine: First results with a Si pad detector and possible applications.

All single photon imaging systems in nuclear medicine use mechanical collimation to form an image of the radioisotope distribution on the face of the gamma camera. These collimators impose a hard physical constraint that couples detector sensitivity and spatial resolution. To overcome the sensitivity-resolution tradeoff, a great deal of effort has been put forth to develop electronically-collimated or "Compton" cameras which have the potential for dramatic improvement in sensitivity without sacrificing spatial resolution.

Dr. Eric Lancon, CEA-Saclay: Mesure de la masse du boson W au LEP.

Une breve introduction de l'importance de cette mesure dans le cadre du modele standard et des methodes d'analyses utilisees par les experiences LEP seront presentees. La mesure combinee des quatre experiences LEP etant dominee par les erreurs systematiques, les differentes sources seront detaillees. Les perspectives et l'impact de cette mesure sur les contraintes des autres parametres du modele standard seront exposees.

Semestre d' hiver 2000-2001

8 Nov. 2000 C. Tully, Physics Department Princeton University Recent results of the LEP combined Higgs searches
15 Nov. 2000 G. Tsipolitis, CERN/National Technical University of Athens Heavy flavour production at HERA
6 Dec. 2000 Simone Gilardoni, DPNC Universite de Geneve L' usine a neutrinos - Introduction
20 Dec. 2000 Michaela Biglietti - Marco Musy, DPNC Universite de Geneve Limits on anomalous gauge couplings using WWgamma and Zgammagamma events with the L3 detector at LEP
17 Jan. 2001 Gersende Prior, DPNC Universite de Geneve moved to 24 Jan 2001
24 Jan. 2001 Gersende Prior, DPNC Universite de Geneve Pourqoui mesurer des sections efficases de hadrons et l'experience HARP
31 Jan. 2001 Fabiola Gianotti, CERN What can the LHC do if the Higgs weights 115 GeV?
14 Fev. 2001 D.Miller, UCL Dept. of Physics and Astronomy Prospects for a 350 to 1000 GeV Linear Collider

Dr. C. Tully, Physics Department Princeton University: Recent results of the LEP combined Higgs searches

The data collected from the LEP experiments at sqrt(s)=206.6 GeV contain a handful of high significance candidates for the Standard Model Higgs at 115 GeV/c^2. The overall search sensitivity is presented as well as the statistical significance of this excess. The LEP operation continued running through November to obtain independent data for the search. The results of the extended running are given. Low mass Higgs interpretation in the MSSM is briefly discussed.

Prof. G. Tsipolitis, CERN/National Technical University of Athens.: Heavy flavour production at HERA

In electron proton scattering the dominant mechanism for heavy flavour production is the boson gluon fusion process.This process is directly dependent on the gluon density in the proton. The study of heavy flavours at HERA, provides an important tool for testing pQCD and for understanding the structure of the proton. In this seminar recent results from the H1 and ZEUS experiments on heavy flavour production at HERA are reviewed.

S. Gilardoni, DPNC Universite de Geneve:L' usine a neutrinos

L' usine a Neutrino est une des possibles options pour le futur du CERN après LHC. Son but est de générer le faisceau de neutrinos le plus intense jamais produit. On pourrait ainsi étudier les oscillations de neutrinos et peut-être même observer la violation de CP dans le secteur leptonique! Pendant ce séminaire, on décrira brièvement la machine, en particulier la source intense --4 MW-- de protons, la cible et le système de focalisation (solénoïde de 20 T, corne magnétique, lentille a lithium) des pions et l'accélération des muons. Dans ce contexte, on expliquera deux concepts nouveaux : la rotation de phase et le refroidissement par ionisation. En plus, on discutera les défis de la partie cible et focalisation des pions.

Pour la compréhension du séminaire aucun connaissance particulière en physique des accélérateurs ou de physique des neutrinos n'est requise.

Le séminaire sera donné en français.

F. Gianotti, CERN :What can the LHC do if the Higgs weights 115 GeV?

The LHC potential for Higgs discovery is presented, with emphasis on a light Higgs boson with mass in the region suggested by the LEP hints. Both the Standard Model and the MSSM scenarios are discussed, as well as the complementarity in the expected performance of ATLAS and CMS. The LHC and the Tevatron potentials are briefly compared. Finally, the perspectives for measuring the Higgs boson parameters at the LHC are described.

D. Miller, UCL Dept. of Physics and Astronomy:Prospects for a 350 to 1000 GeV Linear Collider

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Last updated: 17 November 2000, Eduardo Cortina