Scientific Projects

The Theory and Phenomenology Group

 The theory group of CIPHEA includes all the LAPTH physicists working on particle physics, astrophysics and cosmology with a particular interest in phenomenology.

The astrophysics team is recognised for its major contribution to indirect signals of Dark Matter with sophisticated codes for the propagation of cosmic ray anti-protons and positrons, studies of gamma rays, in addition to the study of cosmological scenarios of the early universe as well as neutrino physics. The particle physicists of LAPTH have worked on different aspects of the SM (both QCD and the electroweak theory) as well as supersymmetry and strong electroweak symmetry breaking. Most recent major achievements in the SM concern the calculation of multi-leg processes at one-loop, while beyond the SM, the group is known for precision calculations in supersymmetry as well as for its codes and analyses of the relic density. In this respect the astrophysics and particle physics groups complement each other and allow for a strong collaboration with the experimental groups of LAPP and outside.

A list of publications of the phenomenology group can be found here

 The LHC Experimental Programme

The ATLAS & LHCb experiments operate on the LHC collider at CERN.

ATLAS experiment

The ATLAS experiment has been mainly designed to study the electroweak symmetry breaking mechanism and to investigate theories beyond the Standard Model(SM). The physics program includes precise measurements of known particle properties and the study of SM processes at a centre-of-mass energy never explored before. These processes represent a background to the New Physics.

Activities of the ATLAS group of LAPP

LHCb experiment

The LHCb experiment is mainly devoted to the precise measurement of the CP violation phenomena in the B system and to the study of the rare decays of B particles. The precision measurements that can be done in this experiment represent a window to the New Physics which is complementary to the direct searches.

Activities of the LHCb group of LAPP 

The Astroparticle Experimental Programme

Indirect search for Dark Matter is one of the research topic studied at LAPP, with ground and space based experiments: HESS and AMS.These complementary detection of the various annihilation products are necessary to address the issues related to the nature and the distribution of the dark matter in the universe. The search strategy is based on a precise measurement of the energy spectra of various cosmic components like gamma rays (HESS and AMS) and charged particle as positrons, anti-protons, anti-deuterons (AMS). The energy spectra for those species will be compared with the theoretical expectations to search for any spectral distortion that may be the indirect evidence for dark matter in the universe. This implies to model the distribution of dark matter, the annihilation rates and coupling modes, as well as the propagation of charged particles from the remote regions of our galaxy down to the solar system. All those phenomenological investigations will be performed in tight collaboration between the experimental and theoretical teams. We also note that LAPP is also taking part in the CTA project.

AMS experiment

The Alpha Magnetic Spectrometer (AMS) experiment is a magnetic spectrometer, based on the high energy physics detector principle, with 0.5 m2×sr aperture supplemented with detectors for redundant particle identification. The aim of the AMS, installed on the International Space Station, is to perform a three year long measurement, with the highest accuracy, of Cosmic Rays in the rigidity range of a few 100 MeV to several TeV and isotopic composition up to 15 GeV/n.

A precursor experiment, AMS-01, was flown for 10 days on the space shuttle Discovery in June 1998 and was able to produce relevant results.

A large part of the group has been involved in the construction of the electromagnetic calorimeter of the AMS-02 mission. This sub-detector is a key ingredient to separate the rare positrons from the proton background, as well as the anti-protons from the electron background and to identify gamma rays. Different MSSM configurations have been tested to estimate the AMS sensitivity in the gamma and positron channels and also scenarios assuming clumpy structures in the galactic dark matter have been proposed. Further studies, will include the anti-proton and anti-deuteron annihilation products, in particular by handling the complete propagation issues.

Activities of the AMS group of LAPP

HESS experiment

H.E.S.S. - the High Energy Stereoscopic System - is a system of four large imaging Cherenkov telescopes built in the Khomas Highland of Namibia, at an altitude of 1800 m. The H.E.S.S. experiment aims to provide precise spectral and time variability measurement of sources of very high energy gamma rays and in particular spatial mapping of extended sources such as Supernova remnants.  With its stereoscopic reconstruction of air showers produced in the atmosphere by very high energy gamma rays, and an energy threshold around 100 GeV, the H.E.S.S1. telescope system provides very high angular resolution and background rejection, resulting in an unprecedented sensitivity for the observation of galactic and extragalactic VHE gamma sources.

LAPP joined the HESS collaboration in June 2005 and contributes to the construction of a fifth and bigger telescope which will allow a lower threshold (around 20 GeV) and will increase the sensitivity to very faint sources at high energy: (HESS2)


Activities of the HESS group of LAPP