The study of the Higgs boson pair production is generating a growing interest in the particle physics community, in particular in view of the High-Luminosity phase of LHC. In addition to the Higgs self-coupling, the VVHH coupling is also an important parameter to improve our understanding of the electroweak symmetry breaking, which can be probed through the search for di-Higgs events in the VBF production mode.

The ATLAS detector is ideally suited for such studies, with its design optimised to reconstruct and identify most of the decay products of the Standard Model particles produced in rare physics processes involving Higgs bosons, such as the di-Higgs production modes. This thesis will include some work on the optimisation of the algorithms used to identify jets produced in the hadronization of b-quarks for the upgrade of the ATLAS detector planned for the High-Luminosity phase of the LHC. Those algorithms play a major role in all the final states involving b-quarks, produced in the decay of the top quark and of the Higgs boson for instance.

Very strong constrains on the VVHH coupling can already be achieved with the LHC Run 3 dataset, in particular combining the low and high m(HH) regions. The corresponding analyses are the focus of a collaborative research effort involving several French laboratories members of the ATLAS Collaboration at CERN. The PhD position would complement this research effort, with a particular focus on the analysis of the bbtautau boosted final state, benefitting from the strong expertise of the ATLAS group at CPPM in b-tagging, boosted object identification and di-Higgs studies [1-2].

Applications should include a CV, a letter of motivation, academic records from bachelor to master and contacts of two reference persons willing to provide reference letters.

[1] ATLAS flavour-tagging algorithms for the LHC Run 2 pp collision dataset https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/FTAG-2019-07/

[2] Combination of searches for Higgs boson pair production in collisions at sqrt(s)=13 TeV with the ATLAS detector

https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HDBS-2021-18/

Decays of heavy-quark hadrons allow to perform indirect searches for effects beyond the Standard Model, by comparing the measured decay properties to their Standard Model predictions. Although our world is made of baryons, most such studies in heavy-flavour physics to date are performed with mesons, and our knowledge of heavy-quark baryon properties remains very limited.

In particular, the hierarchy of charm-baryon lifetimes is not well understood theoretically. In fact, for some of the charm baryons, very little is known about their decay rates: many decays have not been observed yet, and the absolute decay rates have never been measured. This is a significant limitation for any searches for physics beyond the Standard Model involving charm-baryon decays, or beauty baryons decays into charm baryons.

The Belle II detector at KEK (Japan) is aimed at precision measurements of properties of beauty and charm hadrons, as well as tau leptons (https://inspirehep.net/literature/1692393). The Belle II collaboration consists of more than 1000 scientists and is taking data since 2019. The key feature of the Belle II detector is the nearly 4pi angular acceptance, which allows to perform the full reconstruction of the visible collision products and calculation of the missing energy. Combined with conservation laws in e+e-->ccbar process (baryon number, electric charge, quark flavours), this allows to fully reconstruct only one charm hadron and deduce the properties of the other one.

This makes Belle II the only current experiment that can collect inclusive samples of charm baryons, regardless of their decay mode, and this way measure the absolute rates of specific decays (https://inspirehep.net/literature/1275621).

This PhD project will focus on applying this technique to measure the absolute decay rates of baryons that contain both charm and strange quarks, where the current knowledge is very limited.

Activities:

Data analysis using Machine Learning techniques, participation to data taking, participation to Belle II service tasks, activities of outreach and dissemination.

Work context:

This PhD will take place at CPPM, Marseille (https://www.cppm.in2p3.fr/web/en/index.html). Travels to KEK for collaboration meetings, and longer stay for participation to the data taking, are foreseen.

Additional information:

Applicants must hold a Master degree (or equivalent) in Physics, or expect to hold such a degree by the start of employment. Application must include a CV, grade records, a motivation statement and three letters of recommendations.

Prior knowledge of ROOT, C++ or python, is an advantage, but not mandatory.

This thesis is expected to start in October 2025 (if funding is obtained).

Object:

Being forbidden in the Standard Model (SM) of particle physics, lepton flavor violating decays are among the most powerful probes to search for physics beyond the SM. In view of the recent anomalies seen by LHCb on tests of lepton flavor universality in $b \rightarrow s l l$ and $b \rightarrow c l \nu$ processes, the interest of lepton flavor violating decays involving tau leptons in the final state has been greatly reinforced. In particular, several new physics models predict branching fractions of $B \rightarrow \tau l K^*$ and $B \rightarrow \rho \tau l$ decays just below the current experimental limits. This is true as well for the FCNC process $B \rightarrow \tau \tau$ .

The Belle II experiment located at KEK, Japan, started to take data in 2019, aiming at collecting much more data than its predecessor, Belle. The goal of this PhD is to exploit the Belle II data in order to obtain the best experimental limits on lepton flavor violating decays such as $B \rightarrow \tau l X$ , where X is a hadronic system and l an electron or a muon and on the transitions $b \rightarrow d \tau \tau$ , as $B \rightarrow \tau \tau$ . In particular we'd like to explore new B tagging methods in Belle II.

Activities:

Data analysis using Machine Learning techniques, participation to data taking, participation to Belle II service tasks, activities of outreach and dissemination.

Work context:

This PhD will take place at CPPM, Marseille (https://www.cppm.in2p3.fr/web/en/index.html). Travels to KEK for collaboration meetings, and longer stay for participation to the data taking, are foreseen.

Additional information:

Applicants must hold a Master degree (or equivalent) in Physics, or expect to hold such a degree by the start of employment. Application must include a CV, grade records, a motivation statement and three letters of recommendations.

References:

https://arxiv.org/abs/1808.10567

https://arxiv.org/abs/1703.02508

https://arxiv.org/abs/hep-ex/0511015

The CTA (Cherenkov Telescope Array) is a worldwide project to construct the next generation ground based very high energy gamma ray instrument [1]-[2]. CTA will use tens of Imaging Air Cherenkov Telescopes (IACT) of three different sizes (mirror diameter of 4 m, 12 m and 23 m) deployed on two sites, one on each hemisphere (La Palma in the Canary Islands and Paranal in Chile). The observatory will detect gamma-rays with energy ranging from 20 GeV up to 300 TeV by imaging the Cherenkov light emitted from the charged particle shower produced by the interaction of the primary gamma ray in the upper atmosphere.

The unconventional capabilities of CTA will address, among others, the intriguing question of the origin of the very high energy galactic cosmic rays by the search for galactic sources capable of accelerating cosmic rays up to the PeV energies, called PeVatrons. The last few years have been extremely exciting for the PeVatron search since the large field of view detector LHAASO has detected several ultra high energy gamma-ray sources (E??>100 TeV) proving that PeVatrons exist in our Galaxy [3]-[4]. Nevertheless the nature of these sources is still unknown and CTA, thanks to its excellent angular and energy resolution, will be able to precisely study these PeVatrons and to disclose their hadronic or leptonic nature.

The construction of the CTA observatory has started and a first Large-Sized Telescope (LST-1) is already installed and taking data in La Palma. Three more LST telescopes and one Medium-Sized Telescope (MST) will be installed in the next 1-2 years. The camera of the first MST telescope on La Palma (NectarCAM) is fully equipped and should be installed on the structure in 2025.

The PhD project will be divided in two parts. A first part will be devoted to the preparation of the commissioning of NectarCAM and science verification measurements of the Crab nebula which is the standard calibration source for very high energy gamma-ray observations. To this end the candidate will perform the full simulation of the observation that consists in particle shower and telescope Monte Carlo simulations. A detailed simulation of the camera has been developed in the past and will have to be adapted comparing the simulation results to real data taken in the laboratory and on-sky. For the data analysis of both simulation and on sky data the official dataPipe pipeline of the CTA Observatory will be used. The main goal of this part will be to predict the expected performance of the MST telescope in detecting the Crab and prepare the data analysis of on-sky data.

The second part of the PhD project will be focused on the analysis of the data of the coming observation campaign of LST-1 of PeVatron sources detected by LHAASO. Some of these sources are unidentified with no very high energy counterpart. Even if LST-1 cannot reach enough sensitivity to access energies above 10-50 TeV, it should be able to detect some of them in the 100 GeV-10 TeV energy region for the first time or to provide stringent upper limits contributing significantly to the understanding of these intriguing sources. In the case of detection, thanks to the good angular resolution of the telescope, energy dependent morphology study can be performed. A possible extension of the measurement could be to observe the source at large zenith angle maximizing the detection efficiency at very high energy. The latter would allow to explore the energy region above 10 TeV and to extend to higher energies the study of energy dependent morphology to understand the nature of the source.

The project will include the participation to the LST-1 observation campaign with stays of four weeks in the Roque de los Muchachos Observatory in La Palma.

The CPPM CTA group works since several years both in the building of the NectarCAM camera for MST and in the building and commissioning of the LST-1 telescope. The group also works on the preparatory studies for the research of galactic PeVatrons with CTA [6] and is leading the observation campaign with LST-1 and MAGIC of SNR G106.3-2, which is one of the PeVatron LHAASO sources.

Candidates should send their CV and motivation letter as well as grades (Bachelor, M1, M2) to costantini@cppm.in2p3.fr and cassol@cppm.in2p3.fr. Applications will be selected on the base of qualifications and an oral interview.

[1] Science with the Cherenkov Telescope Array: https://arxiv.org/abs/1709.07997

[2] https://www.cta-observatory.org/

[3] Z. Cao et al. Nature, 594, 33–36 (2021)

[4] Z. Cao et al. (2023) https://arxiv.org/abs/2305.17030

[5] F. Acero et al., Astroparticle Physics, 2023, 150, pp.102850.

The neutrino mass ordering (NMO) is a fundamental property of the neutrinos as yet undetermined. The knowledge of whether the neutrino mass hierarchy is 'normal' or 'inverted' will help distinguish between the various theoretical extensions of the standard model proposed to explain the origin of mass in the neutrino sector. It will also be important to help guide the design of future experiments intended to measure the CP violation.

ORCA (Oscillation Research with Cosmics in the Abyss) is a deep neutrino telescope currently under construction at a depth of 2500m in the Mediterranean Sea off the coast of Toulon. ORCA is optimized for the detection of low atmospheric neutrinos and will provide a determination of the mass ordering with a few years of data taking. ORCA is part of the multisite KM3NeT (Kilometre Cube Neutrino Telescope) research infrastructure, which also incorporates a second telescope array (in Sicily) optimized for the detection of high-energy cosmic neutrinos.

During the thesis at the Centre de Physique des Particules de Marseille the student will have the opportunity to participate to all aspects of the experiment; operation, calibration and evaluation of the performance of the neutrino detection units, optimization of the angular and energy resolution of the event reconstruction algorithms, and finally the measurement of the NMO.

The LHCb group of the Centre de Physique des Particules de Marseille (CPPM) invites applications for a PhD position on semileptonic B meson decays at LHCb and LHCb's heterogeneous real-time selection software.

The LHCb experiment at the LHC proton-proton collider at CERN is dedicated to studies of heavy flavour physics, with the major goal to find deviations from the Standard Model of particle physics in decays of heavy hadrons. After a major upgrade, LHCb restarted data taking in 2022 with Run 3 of the LHC. The unprecedented data sample to be collected until 2025 will be the basis of this PhD project.

As successful candidate, you will play an active role in analysing decays of beauty mesons into final states with an excited charm meson, a lepton and a neutrino using Run 3 data. The aim of these studies is to characterize$B \to D^+ l$ decays with electrons in the final state.

You will perform studies of kinematic distributions of the decay products and asymmetries in these decays, which are sensitive to New Physics effects.

To this end, you will study the multidimensional distributions of the kinematic parameters that characterise the internal degrees of freedom of semileptonic multibody decays. You will employ a multidimentional fit, modeling background processes with templates and including detector resolution effects. The project will require the usage of modern computing techniques and machine learning approaches.

In addition to the physics analysis, you will perform studies for extending the existing real-time analysis software running reconstruction and selection algorithms on graphics processing units (GPUs). This is in preparation of LHCb's next Upgrade, where a data rate five times larger than in Run 3 will have to be processed. Therefore, you will gain experience in developing within a heterogeneous software framework.

The LHCb group at CPPM consists of five permanent researchers, four engineers, two postdoctoral researchers and three PhD students. We have been actively involved in studies of semileptonic and rare B decays, as well as in the development of the data acquisition system.

The position is funded by the ERC Starting Grant ALPaCA for exactly three years. As successful candidate you will be part of the doctoral school “Physics and Sciences of Matter” of Aix Marseille University, and travel to CERN regularly.

Requirements:

Applicants must hold, or are about to obtain, a Master's degree in physics. Good knowledge of particle physics, mathematical methods of data analysis, and computer programming are required.

Application details and deadlines:

Applications should include a statement of interest (1 page), a CV (max 2 pages), two reference letters and if already available the (preliminary) grades of the Master's degree. The statement of interest, CV and grades should be uploaded in the CNRS portal:

https://emploi.cnrs.fr/Offres/Doctorant/UMR7346-ANNPOR-122/Default.aspx?lang=EN

Please arrange for the letters of reference to be sent to Dorothea vom Bruch (dorothea.vom.bruch@cern.ch) by the application deadline. The appointment will start on October 1st 2024.

Dark matter is one of the great enigmas of fundamental physics today. Its contribution to the total mass of the Universe is 85%, but it cannot be explained within the framework of the Standard Model of particle physics (SM). However, several candidates for dark matter exist in theories beyond the SM: this is the case of the axion, one of the best-motivated candidates as it also explains the absence of CP violation in the strong interaction.

The discovery of axions requires the invention of new experimental techniques. Several proposals have emerged in recent years. MADMAX is one of the few that is sensitive to the mass domain around 100 micro-eV, favored by theory. For this reason, it has attracted the attention of the scientific community since 2016, when it was first proposed. Today, MADMAX is a collaboration of 50 scientists from German and French laboratories (including CPPM since 2019) and is part of the DMLab International Research Laboratory, installed at DESY-Hamburg. Based on the innovative concept of dielectric haloscope, MADMAX will consist of a booster made of 80 1-meter-diameter disks that need to be positioned to micrometer precision at a temperature of 4 degrees Kelvin and in a magnetic field of 9 T. In order to realize this detector, which will take data at DESY after 2030, the MADMAX collaboration is in an R&D phase, which will be concluded by the construction and operation of a prototype whose main aim is to demonstrate the feasibility of the dielectric booster concept.

The aim of the thesis is to conduct a search for axions in an uncharted phase space by commissioning and analyzing data from the prototype. The student will contribute to the realization and mechanical characterization of the dielectric disks and their interface with the piezoelectric motors developed at CPPM. The prototype will be assembled in an experimental hall on the DESY campus, then inserted and tested at liquid helium temperature in a cryostat in 2025-2026. After these initial tests, the data from which will be analyzed by the student, the prototype will be sent to CERN for long-term tests between 2027 and 2029, under the supervision of CPPM, in a magnetic field of 1.6 T. The data analysis carried out by the student will allow to search for axions around 100 micro-eV using the innovative concept of the dielectric haloscope, with unprecedented sensitivity to axion-photon coupling.

In this context, the student will be required to make regular visits to DESY and CERN, in particular to take part in detector installation and data acquisition.

Requirements:

1. Education: master in experimental particle physics

2. Programming: knowledge in python or C++

3. Language: fluency in spoken and written English

The application consists of:

1. a motivation letter

2. CV (2 pages maximum) and university grade transcripts (for all degrees)

3. Three reference letters

More details about the CPPM Dark Matter team: https://www.cppm.in2p3.fr/web/en/research/particle_physics/#Dark%20Matter

In the late 90s, measurements of the distance of Supernovae and the redshift of their host galaxies revealed that the expansion of the Universe was accelerating. More than 20 years after this discovery, the nature of the dark energy at the origin of this phenomenon remains unknown.

The $\Lambda$ CDM concordance model describes a homogeneous, isotropic Universe on large scales, subject to the laws of general relativity (GR). In this model, most of the Universe's energy content comes from cold dark matter and dark energy, introduced as a cosmological constant. The latter behaves like a perfect fluid with negative pressure p, equation of state p = - rho, where rho is the energy density.

Some alternative models (see [1] for a review) introduce scalar fields (quintessence) whose evolution is responsible for the accelerated expansion. These scalar fields can vary in time and space. They can therefore have a time-dependent equation of state and generate anisotropic expansion.

Other models propose to modify the law of gravitation on large scales, mimicking the role of dark energy.

Supernovae remain one of the most accurate probes of the Universe's expansion and homogeneity. In addition, part of the redshift of galaxies is due to a Doppler effect caused by their particular velocities. We can then use supernovae to reconstruct the velocity field on large scales, and measure the growth rate of cosmic structures. This will enable us to test the law of gravitation.

An anisotropy of expansion on large scales, a modification of GR, or an evolution of the equation of state for Dark Energy, would all be revolutionary observations that would challenge our current model.

Until now, supernova surveys have gathered data from multiple telescopes, complicating their statistical analysis. Surveys by the Zwicky Tansient Facility (ZTF: https://www.ztf.caltech.edu/) and the Vera Rubin/LSST Observatory (https://www.lsst.org/) will change all that. They cover the entire sky and accurately measure the distance to tens (hundreds) of thousands of nearby (distant) supernovae.

The CPPM has been working on ZTF data since 2021 and will publish a first cosmological analysis in 2025 with ~3000 SN1a. We have also been involved in the construction and implementation of LSST for years, preparing for the arrival of the first data this summer.

Within the group, we are working on the photometric calibration of the ZTF survey, essential for the measurement precision we need (see ubercalibration [2,3]). A recent PhD student has developed a pipeline to simulate ZTF and measure the growth rate of structures ([4]), and a current PhD student is adapting this exercise to LSST. In addition, a post-doc has just joined the group to work on ZTF, and a Chair of Excellence (DARKUNI) is extending this work by combining these data with spectroscopic data from DESI.

The aim of the thesis is to develop and perfect this analysis pipeline for measuring the growth rate of structures. The totality of 30000 SN1a of ZTF will be available to do the final cosmological analysis of this survey. The thesis coincides also with the arrival of the first SN1a catalogs of LSST.

Other aspects may be added to the thesis, such as the study of the homogeneity of the expansion, the photometric calibration of the data, and so on.

This is an observational cosmology thesis, for a candidate interested in cosmology and data analysis.

[1] https://arxiv.org/abs/1601.06133

[2] https://arxiv.org/abs/astro-ph/0703454v2

[3] https://arxiv.org/abs/1201.2208v2

[4] https://arxiv.org/abs/2303.01198 https://snsim.readthedocs.io/

The context: More than twenty years after the discovery of the accelerated nature of the Universe's expansion, there is still no definitive explanation for its physical origin. Several types of dark energy or even alternatives/extensions to general relativity have been proposed in the literature attempting to explain the acceleration of the expansion. By accurately measuring of both the expansion rate of the Universe as well as the growth rate of structures as a function of cosmic time, we can learn more about this cosmological mystery. Particularly at low redshift when the expansion is accelerated and dark energy dominates the expansion, we are interested in obtaining the best constraints on the growth rate of structures. These measurements can be achieved by combining galaxy positions and their velocities. The statistical properties of the density and velocity field are tightly connected to the underlying cosmological model.

Experiments: Measurements of the expansion and growth rates of the Universe are the main scientific goal of current and future experiments such as the Dark Energy Spectroscopic Instrument (DESI), the Zwicky Transient Facility (ZTF), Euclid and the Vera Rubin Observatory Legacy Survey of Space and Time (Rubin-LSST).

DESI is currently measuring the 40 million galaxy positions (with their redshift) and their lower redshift sample will be the most complete to date.

The ZTF survey will discover more than 5 000 type-Ia supernovae, from which we can derive galaxy velocities. Rubin-LSST will increase this number to the hundreds of thousands.

Goal of thesis: The selected candidate will work towards the joint analysis of DESI and ZTF datasets, which contain millions of galaxies and thousands of type-Ia supernovae. The candidate will get familiarised with the physics and the statistics of galaxy clustering, will code their own analysis pipeline, test it on state-of-the-art simulations, and apply it on real data. The measurement of the growth rate of structures using DESI galaxies and peculiar velocities from ZTF supernovae will enable tests of general relativity on cosmic scales. This study is a key project in the roadmap of DESI and ZTF collaborations.

Profile required: The candidate has to have large interest by cosmology, statistics, data analysis and programming (we use mostly python). English proficiency and team work skills are also required.

Twenty years after the discovery of the accelerating expansion of the universe through supernova measurements, the supernova probe remains one of the most accurate means of measuring the cosmological parameters of this recent period in the history of our universe, dominated by the so-called dark energy.

The Rubin Observatory with the Large Survey of Space and Time (Rubin/LSST) will be commissioned in 2025 and will be fully operational by the end of 2025. It is an 8.4-m telescope equipped with a 3.2-billion-pixel camera, the most powerful ever built.

This telescope will take a picture of half the sky every three nights for ten years. This survey will make it possible to measure billions of galaxies with great precision, and to track the variation over time of all transient objects. Together with many other astrophysical studies, it will be a very powerful machine for determining cosmological parameters using many different probes and, in particular, will impose strong constraints on the nature of dark energy. The LSST project aims to discover up to half a million supernovae. This improvement of two to three statistical orders of magnitude over the current data set will enable precise testing of the parameters of dark energy, test general relativity and also impose new constraints on the isotropy of the universe.

During the thesis, we propose to prepare and then participate in the analysis of the first LSST supernova data. The preparation will be done using existing HSC/Subaru data, as well as the first images of LSST.

The student will participate in the commissioning of Rubin/LSST. He/she will be in charge of pursuing developments in deep learning methods for supernova identification, and applying them to the first observations.

He/she will then take part in the first analyses using the supernovae he/she has helped to identify.

The LSST group at CPPM is already involved in precision photometry for LSST, with direct involvement in the validation of algorithms within DESC/LSST [1][2][3], and has proposed a new deep learning method to improve photometric identification of supernovae [4] and photometric redshifts [5].

[1] https://www.lsst.org/content/lsst-science-drivers-reference-design-and-anticipated-data-products

[2] https://arxiv.org/abs/1211.0310

[3] https://www.lsst.org/about/dm

[4] https://arxiv.org/abs/1901.01298

[5] https://arxiv.org/abs/1806.06607

[6] https://arxiv.org/abs/1401.4064

Scientific Context (3012 / 5000)

Euclid is an M-class ESA mission launched in July, 2023. It is one of the major observatories dedicated to cosmology and understanding the nature of dark energy and dark matter. By combining galaxy clustering and weak gravitational lensing observations, Euclid will provide data on an unprecedented scale and accuracy.

Galaxy clustering (the large-scale distribution of galaxies) and weak gravitational lensing are two of the mission's key observables. Galaxy clustering allows the study of galaxy distribution across the Universe, revealing critical insights into the structure of the Universe, its dynamics and the nature of dark energy. On the other hand, weak lensing enables the inference of dark matter distribution by analyzing the deformation of background galaxies by foreground masses.

The 3x2pt method, which combines galaxy clustering, cosmic shear, and galaxy-galaxy lensing, is one of the most promising approaches to leveraging these observations. This method maximizes information on cosmological parameters, particularly those related to dark energy, by using complementary measurements to reduce potential systematic biases. These analyses will play a key role in constraining essential cosmological parameters and refining our understanding of dark energy and dark matter.

The PhD project:

This thesis aims to exploit data from the Euclid mission to conduct an in-depth study of galaxy clustering and to perform a comprehensive 3x2pt analysis. Specifically, the thesis will be structured around several key objectives:

• Study of Galaxy Clustering : Analyze the 3D distribution of galaxies on a large scale, using photometric and spectroscopic data from the Euclid survey.

• 3x2pt Analysis: Conduct a combined 3x2pt analysis, combining galaxy clustering and weak gravitational lensing, to fully exploit the cross-information between these two observables. Optimize methodologies to reduce systematic uncertainties, such as galaxy bias contamination and photometric redshift calibration.

• Cosmological Constraints: Apply these tools and methods to DR1 and DR2 Euclid data to constrain models of dark energy and dark matter. Compare the obtained results with theoretical predictions from various cosmological models (?CDM models and modified gravity extensions).

This thesis lies at the intersection of cosmological observations and advanced analysis techniques. By exploiting Euclid mission data and applying the 3x2pt method, this project aims to provide crucial cosmological constraints while developing essential methodological tools for next-generation surveys. This work will contribute to improving our understanding of the dark Universe and exploring new approaches to studying dark matter and dark energy.

Scientific environment:

The thesis will be carried out at the Centre de Physique des Particules de Marseille, under the supervision of Stephanie Escoffier and William Gillard. The cosmology team at CPPM is involved in large cosmological survey like DESI, Euclid and Rubin.

Required Skills:

The candidate should have a Master (MSc) in Astronomy/Astrophysics, Fundamental Physics or Data science. He/she should have a strong background in observational cosmology and statistics, and an interest in advanced methodological approaches and statistical inference techniques relevant to cosmological surveys. Experience in data analysis and programming (Python, C++), and familiarity with handling large datasets is not required but would be advantageous.

A CNES grant has been awarded for this project.

Application with attachments must be submitted via the CNES recruitment system Digital Recruitment, click Apply.

https://recrutement.cnes.fr/en/annonce/3421579-25-087-combined-analysis-of-galaxy-clustering-and-weak-lensing-with-euclid-13009-marseille

Application should include:

Cover letter - statement of motivation and research interests

CV (summarizing education, previous positions and academic work - scientific publications)

Copies of the original Bachelor and Master's degree diploma, transcripts of records

Documentation of English proficiency

List of publications and academic work that the applicant wishes to be considered by the evaluation committee

Names and contact details of 2-3 references (name, relation to candidate, e-mail and telephone number). In addition, arrange for each of the references to submit their letters to Dr. Stephanie Escoffier (escoffier@cppm.in2p3.fr) and Dr. William Gillard (gillard@cppm.in2p3.fr) before the deadline.

Application Deadline is 2025 March 14

Mission :

The research work forms part of the Prompt-Gamma Time Imaging (PGTI) project, funded by the ERC, which aims to provide an instrumental and methodological proof of concept for real-time monitoring, using real data, of the emission distribution of Gamma Prompts (GPs) in the context of hadrontherapy. A detection system placed around the patient - consisting of a beam monitor and gamma detectors - with a temporal resolution of 100 ps provides time-of-flight measurements of the particles involved in the treatment. The first objective of the proposed mission is to use this data to be able to detect as early as possible any significant divergence between the actual treatment and the treatment plan (simulated upstream), and to stop the treatment if necessary. The final objective is to be able to estimate the dose deposition profile from the time-of-flight measurements with sufficient accuracy to adjust the treatment in real time in relation to the treatment plan.

Activités :

The PhD candidate recruited will join the imXgam team at the Centre de Physique des Particules de Marseille, which is responsible for developing the data processing methodology for the PGTI project.

He/she will develop a research activity at the interface between information sciences and medical physics in order to explore applications of artificial intelligence for time-of-flight data in hadrontherapy. He/she will pursue the following main objectives: i) perfect our approach to 3D reconstruction of GP vertices based on an optimisation problem that incorporates the physics of hadrontherapy (e.g. in particular by analysing simulated and real data available in order to incorporate suitable regularisations). The results obtained at this stage will be used in particular to optimise the design of the instrument for maximum spatial resolution; ii) evaluate the contribution of machine learning and deep learning methods to jointly estimate the 3D distribution of GP vertices and the anatomical changes (i.e. in electron density) between the time of the treatment plan and the time of the actual treatment. This essential quantity is often estimated beforehand with significant uncertainties that need to be compensated for. Various strategies will be studied and the most relevant (transfer learning, use of Generative Adversarial Networks) will be evaluated on real data with feedback from doctors and radiophysicists.

The PhD candidate will be part of the PGTI project funded by an ERC Starting Grant led by Sara Marcatili (LPSC) as part of a tripartite collaboration between the Laboratoire de Physique Subatomique \\& Cosmologie (LPSC) in Grenoble, the Centre de Physique des Particules de Marseille (CPPM) and the Centre Antoine Lacassagne (CAL) in Nice.

He/she will benefit from the rich and stimulating multidisciplinary working environment of the imXgam team, the CPPM and the Luminy Campus, including access to the know-how and computing resources of the IN2P3 Computing Centre.