master de physique 2017-2018 · master de physique 2017-2018 spécialité m2 : physique théorique...

Master de Physique 2017-2018

Spécialité M2 : Physique Théorique et Mathématique,Physique des Particules et Astroparticules

Computer project proposal

Lab: CPPM

Research team: KM3NeT

Supervisor: J. Brunner

Tel: 04 91 82 72 49

e-mail: [email protected]

Project title: Study of Counting Rates with data from

the irst KM3NeT/ORCA line

Abstract: At 22/09/2017 the irst detection line of the

KM3NeT/ORCA had been deployed in the Mediterranean

Sea close to Toulon. To prepare for an analysis of

atmospheric neutrinos, the noise (from radioactivity and

bioluminescence) of the photomultipliers has to be

understood. The goal of the proposed project is to

characterise the noise level of the 558 individual

photomultipliers, to establish timelines and to separate

contributions from bioluminescence and radioactivity.

Used software tools : C++, Root, KM3NeT speciic

libraries for data access

References: http://orca.mon.km3net.de/


Spécialité M2 : Physique Théorique et Mathématique, Physiquedes Particules et Astroparticules


Lab: CPPM

Research team: CTA

Supervisor: Franca CassolTel: 0491827248e-mail: [email protected]

Project title: Muon detection rate estimation for Cherenkov telescope calibration

Abstract:CTA (Cherenkov Telescope Array) is a worldwide project to construct the

next generation ground based very high energy gamma ray instrument

[1]. CTA will use more than hundred Imaging Air Cherenkov Telescopes of

three diferent sizes (mirror diameter of 4 m, 12 m and 23 m) [2].

Atmospheric muon images are used as a powerful method to calibrate the

optical throughput of each telescope [3]. Particular care has to be taken

with the estimation of the detection muon rate in order to record enough

muon events for a precise calibration but not to overload the acquisition

system.

The student will develop a program to calculate the muon and the proton

lux incident on a CTA middle size telescope (MST), on the base of lux

analytical parameterizations. Eventually, he will test some muon lagging

algorithms and will estimate both the muon selection eiciency and the

proton rejection eiciency, so as to evaluate the expected muon lagging

detection rate.

The irst part of the project can be developed in C/C++ or in python. The

second part will be based on the CTA python analysis code.

References:[1] Science with the Cherenkov Telescope Array: https://arxiv.org/abs/1709.07997[2] https://www.cta-observatory.org/[3] Using Muons rings for the optical throughput calibration of the Cherenkov Telescope Array, CTA Internal Note COM-CCF/150310


Spécialité M2 : Physique Théorique et Mathématique, Physique des Particules et

Astroparticules


Lab: CPPM

Research team: LHCb

Supervisor: Julien Cogan

Tel: 04 91 82 76 18


Project title: Standalone muon reconstruction in modern C++

Abstract:

he LHC phase II will produce an unprecedented amount of data. he online or

ofline reconstruction of these data represents a true challenge for the

experiments. Progress of processor technology improves the CPU power of the

processors available on the market every year, embedding more and more CPU

cores. However, to beneit from this gain, the software applications must be

optimized for the new processor architecture and need to be heavily parallelized.

he ATLAS and LHCb collaborations are developing a common framework

allowing the parallelization of their reconstruction software. he goal of the

proposed computer project is to convert an existing LHCb stand-alone muon

reconstruction algorithm following the guidelines of this new framework and to

assess its performances. With this hands-on exercise, the student will understand

the basic concepts of parallel programming and learn some key features of

modern C++. He or she will get familiarized with techniques of greatest

importance in High Energy Physics in the near future.

mailto:[email protected]?subject=M2%20computing%20project



Astroparticules


Lab: CPPM

Research team: group Astroparticule

Supervisor: Paschal Coyle

Tel: 0491827253


Project title: KM3NeT event display on an IPAD

Abstract:

KM3NeT/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 hierarchy with a few years of data taking. ORCA is part of the multisite KM3NeT research

infrastructure, which also incorporates a second telescope array (in Sicily) optimized for the detection

of high-energy cosmic neutrinos. The irst ORCA detecion strings have recently been deployed and

are providing high quality data.

When analyzing events it is useful to have an event display to study the details of the events. The

touch and Augmented Reality capabiliies of the IPAD open up interesing possibiiies for improved

interacivity during the visualisaion of such events. Using the touch screen one can easily zoom in

and out of the display, rotate the event, select objects etc.

The project will be to explore this concept using the Apple IPAD. A prototype project (writen in Lua)

already exists for the IPAD within the CODEA framework , but needs to be improved. An IPAD will be

made available to the student for the duraion of the project.

References:htp://www.km3net.org

htps://codea.io/

http://www.km3net.org/

https://codea.io/



Astroparticules


Lab: CPT

Research team: Nanophysics

Supervisor: Adeline CrépieuxTel: 04 91 26 95 30


Project title:

From Fabry-Perot oscillaions to Coulomb blockade in a quantum wire

Abstract:The aim of this project is to calculate using Mathematica the density

of states of a quantum wire in the presence of two impurities of

arbitrary potential strength. Taking the solution of the Dyson

equation for the retarded Green function of the system, the student

will draw the density of states as a function of position and energy

and will study how the impurity potential strength changes its

proile.

References:

R. Zamoum, M. Guigou, C. Bena, and A. Crépieux

Phys. Rev. B 90, 085408 (2014)

htps://arxiv.org/abs/1402.5285

http://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.085408

https://arxiv.org/abs/1402.5285



Astroparticules


Lab: Center for CardioVascular and Nutrition research (C2VN) and Centre

de Physique Théorique (CPT)

Research team: Adenosinergic system and cardiovascular diseases and

Statistical Physics and Complex Systems

Supervisor: Dr Stéphane DELLLIAUX and Xavier LEONCINI

Tel: 06.13.38.63.47 and 04.91.26.95.38


Project title: Complexity modelling of physiologic time series

Abstract:Physiologic systems are extraordinarily complex, especially humans. Living organisms can be

observed from signals they generate that are mostly nonstationary and nonlinear, challenging usual

approaches such as mechanistic homeostasis and biomedical statistics i. Physiologic time series contain

usually unused information that can be revealed using statistical physics concepts and tools such as

chaos theory and fractal properties analysisii.

Main goal of this project will be to set up a test bench of several properties for heart beats time series

to detect fractal dynamic breakdown. This test bench will be adapted for human heart beats time series

that have been collected form normal and pathological (systemic scleroderma) subjects.

An important methodologic challenge will be how to detect and quantify the scaling and correlation

properties of physiologic time series, which are typically not only irregular, but also nonstationary

(i.e., their statistical properties change with time). The student will have to screen, to choose, to

program and to compute some adapted mathematical tools from a set of already used techniques on

already collected real database.

References:

i Goldberger AL. Heartbeats, hormones, and health: is variability the spice of life? Am J Respir Crit Care

Med. 2001 May;163(6):1289-90.

ii Goldberger AL. Fractal dynamics in physiology: alterations with disease and aging. Proc Natl Acad Sci U S

A. 2002 Feb 19;99 Suppl 1:2466-72.



Astroparticules


Lab: CPT

Research team: Particle physics

Supervisor: Aoife Bharucha

Tel:


Project title: Calculating the relic density of ALPs mediated dark matter

beyond freeze out.

Abstract:

The tremendous progress in direct and indirect detection limits on the

nature of dark matter has started to put the standard picture of the freeze

out of WIMPs in question. Here we will consider a simple model where the

dark matter particle interacts with the SM via an axion-like particle which

plays the role of a mediator. The project will involve calculating the relic

density for this model using either the freeze-in, freeze-out, or

reannihilation mechanisms, depending on the region of parameter space.

References:

1) The Four Basic Ways of Creating Dark Matter Through a Portal

By Xiaoyong Chu, Thomas Hambye, Michel H.G. Tytgat.

arXiv:1112.0493 [hep-ph].

JCAP 1205 (2012) 034.

2) Revised constraints and Belle II sensitivity for visible and invisible axion-

like particles

By Matthew J. Dolan, Torben Ferber, Christopher Hearty, Felix

Kahlhoefer, Kai Schmidt-Hoberg.

arXiv:1709.00009 [hep-ph].

3) ALPs Effective Field Theory and Collider Signatures

By I. Brivio, M.B. Gavela, L. Merlo, K. Mimasu, J.M. No, R. del Rey, V.

Sanz.

arXiv:1701.05379 [hep-ph].

Eur.Phys.J. C77 (2017) no.8, 572.



Astroparticules


Lab: CPPM

Research team: RENOIR

Supervisor: GILLARD William

Tel:


Project title: Non-linearity correction of the EUCLID

infrared detector

Abstract:

EUCLID is a ESA space born experiment dedicated to the understanding of the acceleration of the

expansion of the Univers. The EUCLID payload will be launch in late 2021. It is build up of two

instrument, a VISual imager (VIS) that will focus on the measurement of cosmic shear, and a Near

Infrared Spectro-Photometer (NISP) dedicated to the precise measurement of the galaxy redshift and

matter-distribution power spectrum.

The CPPM is in charge of the focal plane of the of the NISP instrument. This focal plane is made of

16 H2RG pixel detector that exhibit an inherent non-linear response. The aim of this project will be

to implement the non linearity correction of the H2RG pixels.

mailto:[email protected]



Astroparticules


Lab: CPPM

Research team: ECO-Xe/Rexan

Supervisor: Dr. Gregory Hallewell

Tel: 0491827642e-mail: [email protected]

Project title: Development of a Python algorithm for real-time ultrasonic analysis of Xenon-Oxygen-CO2 mixtures or use in clinical anaesthesia.

Abstract: Xenon is an ideal anaesthetic gas when mixed up to 80% withoxygen. However it is extremely expensive. Its concentration in thebreathing loop must be monitored in real time along with oxygen and anyiniltrations of metabolic CO2. We are developing ultrasonicinstrumentation for this with real- time readout using Python running inmicrocontrollers.

An of-line algorithm for the ultrasonic determination of Xe/O2 contenthandling variable known temperature, breathing pressure and CO2 contentmust be developed using Python in the Spyder environment for laterimplementation in the instrument irmware. The student would contributeto this algorithm. Prior knowledge of Python / Spyder is an advantage.

References:

[1] “Novel Ultrasonic Instrumentation Developments for Real-time Monitoring of Binary Gas

Mixtures and Flow: Description and Applications”,

M. Battistin et al. Sensors & Transducers, Vol. 207, Issue 12, December

2016, Published by IFSA Publishing

http://www.sensorsportal.com/HTML/DIGEST/P_2878.htm[2] “A combined ultrasonic flow meter and binary vapour mixture analyzer for the ATLAS

silicon tracker” R. Bates et al, 2013 JINST 8 P02006 (Journal of instrumentation)

http://iopscience.iop.org/article/10.1088/1748-0221/8/02/P02006/pdf

[3] “Real-time measurement of Xenon in a binary gas mixture using ultrasound time-of-

flight: a feasibility study” D. Williams, G. Hallewell, E. Chakkarapani and J. Dingley.

Proc. Euroanesthesia2017, Geneva, Switzerlend, June 5-9 2017.

[4] «Rexan : Développement d’un dispositif de récupération et contrôle du Xénon pour

l’anesthésie » J. Busto et al., Appel à projet PACA-Apex2017,

Région Provence-Alpes-Cote -d’Azur, avril 2017.

http://www.sensorsportal.com/HTML/DIGEST/P_2878.htm

http://iopscience.iop.org/article/10.1088/1748-0221/8/02/P02006/pdf

Master de Physique 2017-2018Spécialité M2 : Physique Théorique et Mathématique, Physique des Particules et

Astroparticules


Supervisor: Dirk Hoffmann

Tel: 04.91.82.72

e-mail: Dirk.Hoffmann@In2p3

Project title: Stability of module clocks in a CTA camera

Abstract:

The Cherenkov Telescope Array (CTA, http://www.cta-observatory.org) will explore very high energy gamma rays with two arrays of about 100 telescopes, built by 50 research labs in the whole world. The CTA group at CPPM contributes primarily to the data acquisiton (DAQ) system of the french camera NectarCAM, which will be installed on the middle-sized telescopes (MST) on La Palma.

The CTA cameras are built of several hundred modules, which contain VHF oscillators to identify the instant where a recorded event happened, and which sequences the sampling of the electronic signal coming from the photo-multipliers. Currently we have recorded data with assemblies of 11 to 19 modules during integration of the cameras.

We propose a small research project needing intensive use of computer tools to study the stability and the coherence of the system clocks among different modules and in time. The student will use the recorded data to extract the counter values per event and per module, in order to characterise the different clock oscillators by calculating their statistical parameters, which are to be observed and compared with respect to their stability. From the results of these analyses two conclusions can be derived:

• When the camera will be taking data with all (265 or 80) modules, the DAQ system must be able to compare rapidly the clock counter values of each of the modules following a set of proposed criteria to make sure an eventual malfunction or event mixing of modules is excluded.

• The clock oscillator drift over short and long time will have an impact on the time precision and therefore a lower limit on the precision of the time measurement that will be obtained with a camera of n modules, given that m modules contribute to a given event.

Pour plus d'informations, contacter: [email protected], ☎04.91.82.72.29

PropStageCTA, 30 nov. 17

Centre de Physique des Particules de Marseille

Groupe d'Informatique Temps RéelExpérience CTA


http://www.cta-observatory.org/




Astroparticules


Lab: Centre de Physique Theorique


Supervisor: T. JonckheereTel: 04 91 26 95 36e-mail: [email protected]

Project title: Numerical study of Majorana fermions in topological superconductors

Abstract:

Topological superconductors belongs to a new state of matter, which host at its ends the so-called Majoran fermions (or Majorana bound states). These Majorana fermions have unique properties, like non-abelian statistics, and are promising candidates for innovative quantum computation schemes.

In this project, we will use numerical tight-binding calculations, to study some properties of these Majorana bound states. This can be done on a Kitaev chain, describing simply 1d p-wave superconductor. Or on a more realistic model where a 1d nanowire with spin-orbit coupling is placed in proximity of a standard supecronductor, with an external magnetic ield. This latter model allows to study the transition from a topological system to a trivial one.

References:- Martin Leijnse, Karsten Flensberg, Introduction to topological superconductivity and Majorana fermions, https://arxiv.org/abs/1206.1736 [pedagogical introduction to the subject]

- D. Chevallier, D. Sticlet, P. Simon, C. Bena, Mutation of Andreev into Majorana bound states in long NS and SNS junctions, https://arxiv.org/abs/1203.2643 [example of use of tight-binding calculations]





Astroparticules


Lab: Centre de Physique Theorique


Supervisor: T. Jonckheere / J. RechTel: : 04 91 26 95 36e-mail: [email protected]

Project title: Study of transport in a Normal-Dot-Superconductor junction

Abstract: Andreev relection is a process which occurs at the interface

between a normal metal and a superconductor, where an electron from

the normal metal is relected as a hole, with the transmission of a

Cooper pair in the superconductor. Adding a quantum dot, which has a

controlable resonant level, between the superconductor and the

normal metal allows to explore diferent conigurations which can

increase or decrease the importance of Andreev relection.

In this project, we will study numerically the electronic transport in

such a system out-of-equilibrium. Using a Kedsyh Green function

formalism, one can express the current and the current noise in terms

of the Green function of the dot coupled to the two leads. The

quantities will be computed numericaly as a function of the dot

parameters.

References:

- Andreev relection : https://en.wikipedia.org/wiki/Andreev_relection - The method is similar to the one used in:

D. Chevallier, J. Rech, T. Jonckheere, and T. Martin

Phys. Rev. B 83, 125421 (2011) (https://arxiv.org/abs/1011.3408)

https://en.wikipedia.org/wiki/Andreev_reflection



Spécialité M2 : Physique Théorique et Mathématique, Physiquedes Particules et Astroparticules


Lab: Centre de Physique Théorique

163, avenue de Luminy – case 90713288 Marseille Cedex 9

Research team: Particle Physics

Supervisor: Laurent LellouchTel: 04 91 26 95 17e-mail: [email protected]

Project title: Lattice Yang-Mills theories and Monte-Carlo simulations

Abstract:

This project is meant to be combined with a seminar project on the same subject.

Monte-Carlo methods are one of the only tools that we have to study nonabelian gauge theories in their nonperturbative domain, where they conine quarks and gluons within hadrons. This requires regularizing these theories by placing them on a discrete spacetime. The goal of the combined seminar and computing project is to familiarize oneself with Yang-Mills theories and their most prominent properties, in particular asymptotic freedom and coninement; to understand how to discretize them; to learn thebasics of Monte-Carlo methods; to write a C (or Fortran) code to simulate SU(2) Yang-Mills theory; to perform simulations to study some of this theory's key properties.

Prerequisites for computing project: C, C++ or Fortran, luently enough so that the coding (for the computing project) does not obscure the important physics

References: Michael Creutz, ``Monte Carlo study of quantized SU(2) gauge theory,'' Physical Review D 21 (1980) 2308.



Astroparticules


Lab: Centre de Physiqe Théorique

Research team: Dynamical Systems, Theory and

applications

Supervisor: Xavier Leoncini

Tel: 0491269532


Project title: Chaotic advection, simplectic versus high

order integrators

Abstract: In this project the student will implement and

validate a high order integrator in the context of chaotic

advection. The validation of the code will be made be

comparison with a sixth-order implicit symplectic

scheme.

References:

[1] RI McLachlan, P Atela, The accuracy of symplectic integrators

Nonlinearity, 1992

[2] http://www.maia.ub.edu/~angel/taylor/

https://scholar.google.fr/citations?user=O6FaL14AAAAJ&hl=en&oi=sra

http://www.maia.ub.edu/~angel/taylor/

http://iopscience.iop.org/article/10.1088/0951-7715/5/2/011/meta



Astroparticules


Lab: CPPM

Research team:

Supervisor: Emmanuel Monnier

Tel:


Project title: Development of computer tools and

infrastructure to analyze atlas data

Abstract:

In particular the student will develop the analysis framework to

treat the data taken in 2017 with a prototype trigger chain

developed for the calorimeter upgrade. Depending on the

advancement of the project, s.he will then apply this framework

to analyze the data.

References:



Astroparticules


Lab: CPPM

Research team: ATLAS

Supervisor: Steve MUANZATel: 04.91.82.72.75e-mail: [email protected]

Project title: Reconstruction of di-tau mass at LHC

Abstract:In the decay of each tau lepton, there's a tau neutrino which takes away a fraction of the energy-momentum. This unables tofully reconstruct the tau lepton invariant mass. Some resonances such as the Higgs boson may decay into a pair of tau leptons. The reconstruction of the di-tau mass is then even more complicated although it contains valuable informations. The student will apply and compare diferent methods aimed atcorrecting the di-tau mass from the loss of kinematicinformations due to the two undetected tau neutrinos. Themonte carlo samples will be LHC events for which the ATLASdetector response will be “fast-simulated”.

References:



Astroparticules


Lab: CPT

Research team: Quantum Gravity

Supervisor: Alejandro Perez

Tel:


Project title: Relativistic Themodynamics in Cosmology

Abstract:

Matter fluids in the description of the dynamics of the early universe are

idealized as relativistic free particles which can be bosons or fermions in

thermodynamical equilibrium. The equations of state are easily computable

from statistical mechanics considerations but they are expressed in terms of

integrals that are functions of the mass of the particles, the temperature

and the chemical potential. However, these integrals cannot be evaluated in

close form in general regimes. In this project we will study the evolution of

these quantities numerically in cosmology.

One application of this will be the calculation of an effect estimated in a

recent paper (http://inspirehep.net/record/1636129) using approximations.

References:

Primordial Cosmology, P. Peter, JP Uzan Oxford Graduate Texts 2009.




Lab: CPT


Supervisor: L. RAYMOND

Tel: 06 70 54 05 26


Project title: Quantum Dynamics by the Kernel Polynomial

Method.

Abstract:

The time evolution of a quantum system will be investigated by

using a polynomial expansion of the time-evolution operator.

The proposed method is based on the discrete Fourier cosine

transform written in terms of Chebishev polynomials. Some

examples could be investigated such as the dynamics of a

wave-packet in diferent geometries of the potential, or some

properties of electrons moving in solids.

References:

The kernel polynomial method, A. Weiße, G. Wellein, A.

Alvermann, and H. Fehske, Rev. Mod. Phys. 78, 275

Dynamical spin Hall conductivity in a magnetic disordered

system, T. L. van den Berg, L. Raymond, and A. Verga, Phys.

Rev. B 8✪, 245210


Spécialité M2 : Physique Théorique et Mathématique, Physique des Particules et Astroparticules


Lab: Centre Interdisciplinaire de Nanoscience de Marseille (CINaM/CNRS). Research team: Theory and Computer Simulation Department. Supervisor: Andres Saul Tel: 06 62 92 28 88 e-mail: [email protected] Project title:

Calculation of the ground state properties of quantum magnets. Abstract: The thermodynamic properties of a magnetic system formed by quantum spins whose interactions can be written as a Heisenberg Hamiltonian can be found by diagonalizing the Hamiltonian matrix. The practical usefulness of this “brute force” approach is limited by the exponential growth of the Hilbert space size. For example, a system of N spin-½ particles has 2N degrees of freedom. Memory and computer time restrict the use of full diagonalization methods to N = 16 to 20. The aim of the project is to implement the DMRG (Density Matrix Renormalization Group) which is an iterative method allowing to calculate in an accuracy and efficient way the ground state of 1D or quasi 1D systems. For comparison purposes, the student will first implement a program that diagonalizes the full Hamiltonian and then the DMRG algorithm. References:

S. R. White, Phys. Rev. Lett. 69, 2863 (1992).

S. R. White, Phys. Rev. B 48, 10345 (1993).

K. A. Hallberg, Advances in Physics 55, 477 (201)

https://github.com/afeiguin/comp-phys/blob/master/13_01_DMRG.ipynb




Lab: CPT

Research team: Equipe 4, Quantum Gravity

Supervisor:

Tel: Simone Speziale (with PhD student Giorgio Sarno)


Project title:

Numerical Evaluation of Spinfoam Amplitudes

Abstract:

One hundred years after the discovery of General Relativity and

Quantum Mechanics we still lack a coherent theoretical picture

putting these two pillars on common grounds. An attempt to

build a theory of quantum gravity starting from a background

independent, non-perturbative, approach is given by Loop

Quantum Gravity (LQG). At CPT we are currently studying the

dynamical behavior of the spin network's kinematical states of

LQG, exploring the EPLR model [1,2] in the framework of

Spinfoam Theory.

Over the last year we have developed methods to evaluate the

dynamics numerically. Part of this uses numerical integrations of

hypergeometric functions on Mathematica, and part a C code

for Clebsch-Gordan coeicients.

The student will focus on the irst part, and study numerical

integration on Mathematica, learning irst basic aspects of the

software and then more advanced once related to numerical

instabilities at high oscillatory frequencies. He will review and

understand the results we have obtained, and if particularly

motivated can also help us pushing them further.

For a student with a strong numerical background the project

can also extend to the second part of the algorithm, based on a

C program developed in [3], for which we need to optimise RAM

storage for large arrays of data.

Both projects it into a larger research program aimed at

computing quantum gravity dynamics, and would be relevant in

the future for theoretical physical processes such as the Black

Hole-White Hole transition introduced in [4] as well as

amplitudes relevant for cosmology.

References:

[1] C. Rovelli, F. Vidotto, Covariant Loop Quantum Gravity: An

Elementary Introduction to Quantum Gravity and Spinfoam

Theory, Cambridge University Press (2014).

[2] J.Engle, E.Livine, R.Pereira and C.Rovelli, LQG vertex with

inite

Immirzi parameter, Nucl.Phys. B799 (2008), 136--149.

[3] H.W. Johansson, C.Forsse’, Fast and accurate evaluation of

Wigner 3j, 6j, and 9j symbols using prime factorisation and

multi-word integer arithmetic, SIAM J. Sci. Statist. Comput. 38

(2016).

[4] M.Christodoulou, C.Rovelli, S.Speziale, l.Vilensky, Realistic

Observable in Background-Free Quantum Gravity: the Planck-

Star Tunnelling-Time,Phys. Rev. D 94 (2016), 084035.



Astroparticules


Lab: CPPM

Research team: ATLAS

Supervisors: Laurent Vacavant, 04 91 82 76 24, [email protected];

Alessandro Calandri, 04 91 82 72 63, [email protected]; Arnaud

Duperrin, 04 91 82 76 25, [email protected]

Project title: b-quark identiication with ATLAS at HL-LHC

Abstract:

The Higgs boson was discovered in July 2012 by the ATLAS and CMS

collaborations at the LHC, and led to a Nobel Prize for F. Englert and P.

Higgs in 2013. Since then and till 2019, the LHC experiments are collecting

a lot of new data, in order to better characterize the Higgs boson and to

possibly ind evidences of new physics beyond the Standard Model.

However, in order to increase by a factor 100 the amount of useful data

we already have, the LHC and its detectors will be upgraded for the High-

Luminosity phase of LHC (2025-2035). The ATLAS group at CPPM, building

on its previous expertise, is developing a new pixel detector to this end.

This high-tech detector plays a fundamental role to measure the

trajectories of charged particles and to identify jets of particles stemming

from the hadronization of bottom quarks. This ability, a.k.a. b-tagging, is

instrumental to the success of the ATLAS and LHC physics program: Higgs

coupling to top quarks and self-coupling, searches for new heavy particles.

The student will analyze simulated events and assess the b-tagging

performance of various design options under consideration for the pixel

detector. The project provides an opportunity for the student to get a irst

exposure to a broad spectrum of topics: LHC physics, silicon detectors, b-

tagging algorithms including Machine Learning algorithms (ANN, BDT).

The project requires the use of the ROOT analysis framework and the

writing of C++ code: their prior knowledge is desirable but not mandatory.


http://root.cern.ch/

http://atlas.cppm.in2p3.fr/

http://atlas.cern/





Astroparticules


Lab: CPT

Research team: Dynamical Systems, Theory & Applications (E7)

Supervisor: Michel Vittot, CNRS, CPT

Tel:

E-Mail: [email protected]

Project title: Computation of Trajectories of Particles in a

Magnetized Plasma of a Tokamak

Abstract:

The goal is to plot some trajectories of a particle in a magnetized

plasma of a Tokamak. We irst assume that the retro-action of this

particle on the strong toroidal magnetic ield is neglected. The

electric ield is also neglected in this irst work. Indeed the electric

energy is a few percent of the magnetic energy. A reduced phase space

description (the guiding-center approach) is very useful. Some "Internal

Transport Barriers" may also be build by this work.

References:

A.J.Brizard, T.S.Hahm: "Foundations of nonlinear gyrokinetic theory",

Review of Modern Physics 79, 421 (2007).

L.de Guillebon, M.Vittot: "Gyro−gauge independent formulation of the

guiding−center reduction to arbitrary order in the Larmor radius".

Plasma Physics and Controlled Fusion 55, 105001 (2013).




Lab: CPT

Research team: Cosmology

Supervisor: Bel & Marinoni

Tel:


Project title: Numerical integration of cosmological orbital

motion

Abstract:Modern cosmology is described within the framework of General Relativity in which the geometry of space and time is subject to dynamical change. All current models of our universe have in common that space is presently in a state of expansion. The question addressed in this project is whether, and to what extent, does cosmological expansion inluence the dynamics on small scales(as compared to cosmological ones), particularly in our Solar System.Here our reference order of magnitude for any efect is given by the apparent anomalous acceleration of the Pioneer 10 and 11 spacecrafts, which is of the order of 10^(-9) m/s^2.

The student will integrate numerically the geodesic equations of

motion of a test particle in a perturbed Robertson & Walker metric

and gauge the amplitude of the resulting cosmological efects.

He/she will accomplish this by contrasting, for the same initial

conditions, the cosmologically corrected orbital path against the

standard Schwarzschild one.



Astroparticules


Lab: CPPM - Centre de Physique des Particules de Marseille

Research team: RENOIR - Equipe cosmologie

Supervisor: Stephanie ESCOFFIER

Tel: 04 91 82 76 64


Project title: Estimators of the 2-pt correlation function

Abstract:

In cosmology, the study of large scale structure is performed via the

measurement of the 2-point correlation function. A standard estimation of the

correlation function is the Landy-Szalay estimator, which is supposed to reach

minimal variance. This estimator is a linear combination of ratios between

paircounts of data and/or random catalogues (DD, RR and DR). The computer

project proposal consists in studying alternative estimators, using the CUTE

software. This work will be done by optimizing the time processing in a

multi-thread environment as the Dark Energy Center.

References:

An optimized correlation function estimator for galaxy surveys, M.

Vargas-Magana et al., Astron. Astrophys. 554 (2013) A131, arXiv:1211.6211

[astro-ph.CO]

A comparison of estimators for the two-point correlation function, M. Kerscher

et al., Astrophys. J..535 (2000) L13-L16, arXiv:astro-ph/9912088

master de physique 2017-2018 · master de physique 2017-2018 spécialité m2 : physique théorique...

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