Rencontres IPhT/SPP


Cette série de rencontres entre l’Institut de Physique Théorique et le Service de Physique des Particules de l’Irfu qui porte sur la physique des particules et la cosmologie a démarré en juin 2008. Ces rencontres ont pour objectif de favoriser les échanges entre théoriciens et expérimentateurs travaillant sur des thèmes de recherche communs.

Au rythme de deux ou trois réunions par an, chaque rencontre aborde un thème choisi en cosmologie ou en physique des particules. La formule retenue pour ces réunions consiste, en première partie, en deux exposés sur la thématique abordée qui sont faits par un théoricien et par un expérimentateur. Ces exposés, relativement courts (environ 30'), laissent une place suffisante à des discussions informelles. Ils sont suivis, en deuxième partie, par une « foire aux questions » pendant laquelle un théoricien et un expérimentateur répondent à tour de rôle à des questions préalablement sélectionnées à partir de suggestions faites par les physiciens. Afin de favoriser discussions et échanges d’idées, ces réunions se veulent aussi pédagogiques que possible. La durée prévue de chaque rencontre est d’une demi-journée.


Rencontre n.11:

Date et heure: Jeudi 26 septembre 2013, 14h

Lieu: Salle Galilee, Sap (Bat. 713)

Thème: La Physique du Higgs



14:00 Ph. Brax(IPhT), P. Brun (SPP) Bienvenue
14:00 - 14:30

Brando Bellazzini(IPhT)

" Higgs Mechanism "  
14:30 - 15:00

Boris Tuchming (SPP)

" Collider Observables "  
15:00-15.15 Jean-Yves Ollitrault (IPhT) "The Landau-Yang Theorem"
15:15 - 15:30 Fabrice Couderc (SPP) "How to Measure the Spin of the Higgs Particle? Scalar or Pseudo-scalar?"  
15:30 - 15:45 Stephane Lavignac (IPhT) " The Hierarchy Problem"  
15:45-16:00 Coffee Break  
16:00 - 16:15 Philippe Brax (IPhT)

" Higgs as Inflation, Dark Energy?"

16:15 - 16:30 Roy Aleksan (SPP) " News from Future Colliders "  
16:30-16:45 Brando Bellazzini (IPhT)

"Higgs Lifetime and Vacuum Stability"

16:45-17:00 Robi Peschanski (IPhT) "Diffractive Higgs"


Envoyez nous vos commentaires! ,





Rencontre n.10:

Date et heure: Jeudi 6 decembre 2012, 10h

Lieu: Salle A. Berthelot, SPP (Bat. 141)

Thème: Les axions


10:00 E.Mazzucato (SPP), F. Vernizzi (IPhT) " Bienvenue "
10:00 - 10:30 Philippe Brax (IPhT) " Shining Light on Modifications of Gravity "  
    Many modifications of gravity introduce new scalar degrees of freedom, and in such theories matter fields typically couple to an effective metric that depends on both the true metric of spacetime and on the scalar field and its derivatives. Scalar field contributions to the effective metric can be classified as conformal and disformal. Disformal terms introduce gradient couplings between scalar fields and the energy momentum tensor of other matter fields, and cannot be constrained by fifth force experiments because the effects of these terms are trivial around static non-relativistic sources. The use of high-precision, low-energy photon experiments to search for conformally coupled scalar fields, called axion-like particles, is well known. In this article we show that these experiments are also constraining for disformal scalar field theories, and are particularly important because of the difficulty of constraining these couplings with other laboratory experiments.  
10:30 - 11:00 Esther Ferrer Ribas (SEDI) " Axion search with the CAST experiment "  
    Axion searches have been exploiting a wide range of experimental techniques to attempt to detect this elusive particle since a few decades. The strategies for galactic, solar and laboratory axions will be briefly described focusing on the solar axion search with the CAST experiment. The results obtained from past data taking campaigns will be presented.  CAST results represent the best experimental limit on the photon coupling to axions and other similar exotic particles in a wide range of axion masses up to 1.16 eV. Besides the limit enters the region favored by QCD axion models for the first time. Expected sensibilities for the extension of the CAST program up to 2014 will be presented. Long term options for a second generation helioscope will be evoked.  
11:00 - 11:20 Pause café    
11:20 - 11:45 Thibault Main de Boissière (SPP) " Axion searches with the EDELWEISS Ge bolometers "  
    The EDELWEISS experiment aims at the direct detection of dark matter in the form of WIMPS using Ge bolometers at 20 mK in a dilution refrigerator installed at the Underground Laboratory of Modane.
In addition to this primary search, Ge bolometers are suitable detectors also for the detection of other particles, such as axions or ALPs.
We will present here preliminary results obtained in the framework of the EDELWEISS-II experiment on different axion-like particles characterized by different coupling mechanisms to ordinary matter, such as the Primakoff effect, the coherent Bragg diffraction and the axio-electric effect.   
11:45 - 12:15 Denis Wouters (SPP) " Effects of axion-like particles on the propagation of gamma-rays in the Universe "  
    Due to their two-photon vertices, axion-like particles can convert into photons in magnetic field and vice-versa. Astrophysical environments can offer large magnetic field strength and/or long baselines, they are thus interesting laboratories for axion-like particle (ALP) searches. For instance ALPs are sometimes claimed to make the Universe more transparent to gamma-rays than conventionally expected, and to be responsible for observed effects. We propose to present a critical reassessment of this statement. By doing so, we will introduce a new observable for gamma-ray telescopes that can be used to put constraints in the ALP coupling/mass plane, based on the magnetic turbulence induced noise in the energy spectra of gamma-ray sources.  
11:15 - 12:45 Jeremy Neveu (SPP) " Experimental constraints on light mass scalar field models in the SNLS and CMS experiments "  
    The Galileon model is a modified gravity theory that may provide an explanation for the accelerated expansion of the Universe. This model does not suffer from instabilities or ghost problems (normally associated with higher-order derivative theories), restores local General Relativity -- thanks to the Vainshtein screening effect -- and predicts late time acceleration of the expansion. We tested this model against precise measurements of the cosmological distances and the rate of growth of cosmic structure. In this talk, the methodology and the results will be presented and discussed.
The Branon model is a scalar field theory close to the Galileon model. The links with the latter will be discussed. Our plans to constrain its couplings to matter will be presented.

Envoyez nous tous vos commentaires! , .



Rencontre n.9:

Date et heure: Mardi 24 janvier 2012, 14h

Lieu: Salle C. Itzykson, IPhT (Bat. 774)

Thème: La physique des neutrinos


14:00 E.Mazzucato (SPP), F. Vernizzi (IPhT) " Bienvenue "
14:00 - 14:25 Enrico Bertuzzo (IPhT) " Flavor symmetries in the lepton sector "  
14:25 - 14:50 Sandrine Emery (SPP) " T2K "  
14:50 - 15:15 Vincent Durand (SPP) " Double Chooz "  
15:15 - 15:40 Francis Bernardeau (IPhT) " Neutrino mass from cosmological observations "  
15:40 - 16:00 Pause café    
16:00 - 16:25 Guillaume Mention (SPP) " The reactor antineutrino anomaly and experimental status of anomalies beyond 3 flavors "  
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#474 - Màj : 16/09/2013


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