Section de physique
Département de physique nucléaire et corpusculaire

General

Doctoral studies can be undertaken in the following research groups of the DPNC:

• the Hadron Collider Physics Group and in particular the ATLAS experiment at the CERN Large Hadron Collider (contact Prof. Allan G. Clark, Prof. Alain Blondel or Prof. Martin Pohl);

• The neutrino group of University of Geneva offers several possible positions for PhD studies. The PhD is normally completed in four years with a maximal extension to 5 years. The following subjects of studies are possible within the group:(contact. Prof. Alain Blondel)

• the AMS Group, which is currently preparing the Alpha Magnetic Spectrometer experiment for the International Space Station (contact Prof. Martin Pohl);

• The FAST experiment at the Paul Scherrer Institut (PSI), Villigen, aims at an improved measurement of the lifetime of the positive muon, which defines the coupling constant of one of the fundamental forces, G_F.(contact Prof. Martin Pohl)
  

Doctoral studies include both graduate student course work, and research studies leading to the submission and defense of a thesis. Some teaching duties are also required.

Accepted doctoral students are normally employed at the level of Assistant; this provides adequate financial support for the completion of doctoral studies. Candidates for a PhD position should have the equivalent of a Master in Physics from the University of Geneva (4 years of university studies, plus a research activity).

Thesis subjects at University of Geneva (DPNC)

1. ATLAS Experiment at CERN – LHC

The ATLAS experiment is presently being constructed and commissioned; it is expected to be ready to collect the first data with LHC proton-proton collisions during 2008. The main goal of ATLAS is the search for new particles invoked to understand the Electroweak symmetry breaking mystery: Higgs boson, Supersymmetric particles or anomalous W and Z pair production are phenomena that have been advocated. The DPNC is involved in the construction and commissioning of the inner tracking detector, the read-out electronics (RODs) of the Liquid Argon calorimeter, and the development of High Level Triggers (HLT) for the ATLAS experiment.

The work of the student will consist in :

• participation in the commissioning of the Inner Tracking Detectector and studies of its performance;
• participation in the commissioning of the Liquid Argon calorimeterand studies of its performance;
• Data collection and analysis of the first data due in 2008 to study the detector performance;
• The definition of a physics study and the development of an analysis of data for that study.
  

2. FAST Experiment at PSI

The FAST experiment at the Paul Scherrer Institut (PSI), Villigen, aims at an improved measurement of the lifetime of the positive muon, which defines the coupling constant of one of the fundamental forces,G_F.

A first result, based on 10¹⁰ events, is being published. To arrive at the required final sensitivity, several improvements of the time measuring and data acquisition systems are necessary. The student will participate in these upgrade activities, in the data taking foreseen for 2008 and 2009, as well as the analysis and the study of systematics, to establish the reliability and precision of the result.

3. Neutrino Physics, the T2K experiment

• Cross-section measurements with the ND280 detector of the T2K experiment.
  
  The T2K (Tokai-to Kamioka) neutrino oscillation experiment started to operate this year. The experiment is equipped with a very advanced near detector at 280m from the target station (ND280). The primary purpose of the near detector is to measure the neutrino flux and make predictions of what the neutrino flux will be at the far location (Kamioka). But the near detector will also be one of the best tool available worldwide to make cross-section measurements of neutrinos on several material (carbon, water) and for different interaction modes. Charge-current quasi-elastic cross-section are fairly well known by now, but single-pion, coherent pion, and deep inelastic cross-sections still have very large uncertainties. The student will use the data from the NA61 experiment at CERN in which the particle production in the T2K target by 30 GeV protons is measured precisely. These data will be used to predict the neutrino flux at the T2K near detectors, thus allowing a precise measurement of neutrino cross-sections.

• Disappearance of muon neutrino in the T2K experiment
  
  The T2K (Tokai-to Kamioka) neutrino oscillation experiment started to operate this year. The disappearance of muon neutrinos has now been very well established by the atmospheric neutrinos measurement of Super-Kamiokande and later by experiments like K2K and MINOS. Two parameters can be measured when looking at the disappearance of muon neutrinos: sin2(2theta_23) and Delta m2_23. Sin2(2theta_23) is currently constrained by Super-Kamiokande and Delta m2_23 is constrained by MINOS. T2K will be able to improve the Delta m2_23 within the first (or second) year, and it might also improve the sin2(2theta_23) measurement eventually. The student will work on the NA61 experiment at CERN in which the particle production in the T2K target by 30 GeV protons is measured precisely. These data will be used to predict the neutrino flux at the T2K near and far detectors, thus allowing a precise comparison of the muon neutrino rates in the two detectors.

• Search for the appearance of electron neutrinos in the muon neutrino beam in the T2K experiment.
  
  The T2K (Tokai-to Kamioka) neutrino oscillation experiment started to operate this year. The main goal of the experiment is to search for the so far unseen oscillation of muon neutrinos into electron neutrinos. Work will be concentrated in a first instance on the pecise prediction of the intrinsic flux of electron neutrinos in the beam using the data on kaon production acquired by the NA61 experiment. The observed number of interactions producing an electron in the T2K far detector (the large 50 kton Water Cherenkov detector called SuperKamiokaNDE) will then be compared to the predictions to obtain a limit -- or a signal!

• The MICE experiment is an accelerator neutrino experiment dedicated to the demonstration of ionization cooling. DPNC is responsible for the data acqusition the online cluster and the electron muon ranger. The experiment will take data in 2011-2013 and will provide several subjects for theses based on beam and detector setup and data analysis, including the first observations of ionization cooling.

There are also possibilities of doctoral studies at CERN with University supervised from DPNC.

Subject B: Measurement of heavy ions in cosmic radiation

AMS identifies heavy ions, from helium to iron, by combining specific ionization energy loss in the spectrometer sensors, with the intensity of signals in a Cherenkov detector and the measurement of total energy. Thus a detailed analysis of the chemical composition of cosmic radiation will be performed for the first time as a function of the nuclei energy. In some ranges of energies, unstable isotopes can be identified, thus allowing a determination of their confinement time in our galaxy.
These measurements will allow a better understanding of production, acceleration and propagation mechanisms of cosmic rays. Heavy anti-nuclei will also be searched for. Discovery of anti-nuclei, such as anti-oxygen, would point to the synthesis of anti-matter in anti-stars….