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Laboratoire d'Annecy-le-Vieux de
Physique Théorique

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Présentation du Laboratoire d'Annecy-le-Vieux de Physique Théorique (LAPTh)

Le LAPTh est une unité mixte de recherche (UMR 5108) CNRS-INP/Université de Savoielapth-lapp. Le laboratoire est situé à Annecy-le-Vieux, 5km du centre d'Annecy et à 40km du CERN et de Genève. Les activités du LAPTh sont centrées autour de trois grands thèmes de recherche:

  • phénoménologie en physique des particules,
  • astroparticules et cosmologie,
  • physique mathématique: en particulier en théorie des champs, cordes et symétries.

Actualités

Refined background calculations for AMS02

pbarp-lapth

Les derniers résultats de l'expérience AMS-02 ont été annoncés à la mi-avril au CERN. Ce sont les mesures les plus précises à ce jour concernant les flux de protons, d'hélium et le rapport antiproton à proton, prolongeant en même temps la gamme/portée d'énergie de l'expérience PAMELA. Les résultats les plus attendus concernaient la production de l'anti-matière, en particulier la mesure des anti-protons puisque cette dernière peut être produite par la destruction de particules de matière noire qui constitue donc une source primaire. La production conventionnelle du Modèle Standard des anti-protons est menée par les collisions de rayons cosmiques de haute énergie avec la matière interstellaire. Ce mécanisme est donc un mécanisme de production secondaire qui constitue une base importante pour le signal d'une nouvelle physique grâce à la découverte de la matière noire. Les estimations précédentes de cette expérience prédisaient une forte baisse à haute énergie (des centaines de GeV) du rapport antiproton à proton.

Lire la suite : Refined background calculations for AMS02

 

The UGA Idex project pre-selected

investissements avenir
   logo uga


 Université de l’innovation

An important hurdle has been crossed on the way to achieve the goal of establishing the UGA, Université Grenoble Alpes, as a world class research and innovation university. The UGA is a conglomerate of universities and research institutions with a   multi-disciplinary training programme in Grenoble and in the Alps region. The French Ministry of Education and Research has announced that the Idex (Excellence Initiative) pre-project of UGA is one out of three pre-projects that has been selected among 7 other applications. This paves the way to the submission of the full project which will be reviewed by an international panel whose results will be made public in January 2016. In case of success this date will mark a new beginning for the new institution and will be a major boon for all the laboratories involved. For LAPTh this will reinforce our contribution to the Excellence Laboratory Initiative (Labex) Enigmass and build upon  our efforts in building a strong collaboration with the Grenoble laboratories. 

More details on the UGA Idex project can be found here (in French).

The project stands on excellent scientific foundations. For example, 1 out of  5 inhabitants in the Grenoble Alpes region are, in one way or the other, involved with research and innovation, see this short clip .

   

Lectures on Amplitudes and Symbols

monodromy giorgios

With the advent of the LHC and the need for ever increasing accuracy, techniques in loops calculations have witnessed tremendous progress borrowing from highly complex mathematical structures and improving and adapting these structures. A very recent development concerns  the use of symbols. Giorgios Papathanasiou will introduce some of  these concepts starting from an elementary exposition of how these objects appear from the integrals one encounters in the evaluation of scattering amplitudes beyond tree-level. There will be 4 lectures:

1: Analytic structure of scattering amplitudes and Feynman integrals. Algebraic and transcendental functions. Classical polylogarithms.

2: Multiple polylogarithms (MPL): Integral and Series representations. Shuffle and quasi-shuffle algebras.

3: The symbol map. Properties. Integrability condition. Application: Resolving identities among MPLs and simplifying expressions.

4: (Optional) Advanced topics: The Hopf algebra of MPLs and the coproduct. Bootstrapping amplitudes. Expanding the symbol.

 

Graspa 2015

Undergraduate Summer School in Particle and Astroparticle Physics of Annecy-le-Vieux, July 16-22 2015

The schoolgraspa 2015 aims at introducing Particle Physics and Astroparticle physics to 4th and advanced 3rd year physics students from anywhere in the world. The most recent research topics and results in these fields will be presented. The school consists of 4 days of lectures on LHC Physics, Neutrinos, Heavy Flavours, Astroparticle Physics and Gravitational Waves. Computational tools for these fields will also be introduced during a hands-on session. The students will be immersed in an international research atmosphere. They will be able to spend time and discuss at length with scientists working in the field.

Courses will be in English. No background knowledge on the topics covered beyond a popular science level is assumed. A strong background in Quantum Mechanics is expected, however.

 

A maximum of 30 students will be admitted.

   

PhysTeV Les Houches 2015

lh 2015

In a few weeks the high energy physics team will be going to Les Houches. We will be overseeing the 9th session of the LH PhysTeV. This session will coincide with the first beams at the LHC which will soon be  running at 13TeV.

The highlight of the 2015 Les Houches Edition is to take full advantage of the data that has been collected at the LHC so far and prepare for the future runs. The Workshop will devote particular attention to:(i) Higgs physics, and how it shapes our view on the mechanism of electroweak symmetry breaking; (ii) related searches for New Physics and (iii) progress in new techniques for the calculations and simulation of Standard Model processes. These activities will be conducted in close connection with the development and improvements of related theory tools, in particular of Monte-Carlo event generators.

The Workshop proper runs over one year, including two meetings in Les Houches in the month of June, and exchanges and collaborations before and after the meetings. The meetings in Les Houches will consist of two sessions:

Session I: 1-10 June 2015with emphasis on SM-related issues

Session II: 10-19 June 2015   with emphasis on New-Physics searches

Site of the LH2015 session   Wiki of LH2015

 

A course on Nonequilibrium Processes

kirone2Kirone Mallick from the Institut de Physique Théorique (IPhT) CEA Saclay is giving a set of lectures describing recent advances   in systems far from equilibrium. After a review of equilibrium thermodynamics, the lectures will introduce  the fascinating identities of Jarzinski and Crooks which quantify the transient violations of the second principle. This will be followed by the fluctuation theorem of Gallavoti-Cohen. Here is the exciting programme

1. Review of statistical physics: Equilibrium versus Non-equilibrium. Dynamics, Detailed Balance and Time-reversal.
2. Out of Equilibrium: Large Deviations, Generalized Detailed Balance and the Gallavotti-Cohen theorem.
3. Work Identities: the Jarzynski and Crooks identities.
4. The Asymmetric Exclusion Process: Exact Results
5. A unifying framework: the Macroscopic Fluctuation Theory.

   

A Possible solution to the Lithium problem?

poulin serpico

Big Bang Nucleosynthesis (BBN) is an admirable achievement of the standard cosmological model as it very precisely predicts the amount of the most abundant elements, in particular hydrogen and helium. On close inspection the picture is marred by a long standing and annoying problem. Though its abundance is extremely small, the standard predicted amount of lithium is  about a factor 3 larger than what observed in some metal-poor stars believed to trace the primordial abundance. Tweaking the theory of BBN to correct the lithium abundance affects that of the hydrogen or helium to an extent that this is ruled out by the Cosmic Microwave Background (CMB).

In a very recent paper, Pasquale D. Serpico and Vivian Poulin (LAPTh, CNRS) have shown that a loophole in the calculation  of the electromagnetic cascades re-opens the possibility of finding an easy way out to the old problem of the lithium abundance.

Lire la suite : A Possible solution to the Lithium problem?

 

A course on cosmology by Wessel Valkenburg

optimized-wessel Starting Monday 20 January Wessel Valkenburg (Lorentz Institute, Leiden Univ., NL) will give a series of 5 lectures on cosmology. The lectures require no prior knowledge of the subject and is addressed to both theorists and experimentalists, physics PhD students and researchers alike.

The 5 lectures Introduction to Cosmology cover
 
1) The universe today: overview of current understanding, based on Planck, WMAP, SDSS, an many more.
2) Cosmic microwave background as the Planck satellite sees it: from radio signals to spectra of perturbations (and back), and the importance of spectra.
3)  Large scale structure from BOSS, CFHTLens, LSST, Euclid: from angles and redshifts to spectra of perturbations (and back), and a bit on the importance of spectra.
4)  Inflation: probing high-energy physics with BICEP2, Planck, and others.
5) What are the most important pitfalls for cosmologists? Confirmation bias, believe vs pragmatic testing, etc. Where is the Nobel prize hiding?
 
For more information see the LAPTh indico : https://indico.in2p3.fr/category/365/

youtube logo smallThe  (6) videos of the lectures can be found on the LAPTh Youtube Channel

   

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