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# Rencontres de Physique des Particules

Europe/Paris
Salle des actes bât. 7 et Amphi 16.01 (Université Montpellier 2)

### Salle des actes bât. 7 et Amphi 16.01

#### Université Montpellier 2

Place Eugène Bataillon, 34095 Montpellier Cedex 05
Description
L'édition 2012 des Rencontres de Physique des Particules (RPP-2012) aura lieu à Montpellier les 14, 15 et 16 mai.

Manifestation annuelle, ces Rencontres se veulent non seulement un moment d'échange pour la communauté des physiciens théoriciens en physique des particules, mais aussi le moyen de prendre connaissance des avancées dans les thématiques voisines ou parfois même transverses de chacun : physique hadronique, chromodynamique quantique, physique électrofaible, leptons et saveurs, théories au-delà du modèle standard, astroparticules, et/ou autres thématiques en lien avec notre discipline.

Les RPP-2012 seront étalées sur 3 jours plutôt que 2, afin d'intégrer, outre les présentations plénières de revue, des présentations individuelles plus longues (que vous êtes encouragés à soumettre) et/ou des séances de discussions si l'actualité scientifique le justifie.

La tenue des RPP en mai, cette année, nous permettra d'enrichir nos discussions des résultats des conférences d'hiver, tout en les découplant de fait de l'aspect "candidatures CNRS".

En espérant vous voir nombreux aux RPP-2012 (le sable est *sur* les pavés en mai à Montpellier). Le CLO.

The 2012's edition of 'Rencontres de Physique des Particules' (RPP-2012) will take place in Montpellier from May 14th to May 16th.

RPP annual meetings are aimed at gathering the theoretical particle physicists' community, providing the participants with the opportunity not only to present their research topics, but also to make contact with the latest developments in adjacent fields: hadronic physics, QCD, EW, leptons and flavors, beyond standard model theories, astroparticle physics, etc.

RPP-2012 will have a few review talks on selected topics as well as on the latest experimental results, but is mainly devoted to individual theory presentations and discussion sessions in a relaxed environment, subsequently to the winter conferences and in these exciting times for our field.

Looking forward to seeing you soon in Montpellier. The LOC.


Review talks:
* Higgs boson search and statistical methods at the LHC - Dirk Zerwas (LAL, Orsay)
* Physics Beyond the Standard Model - Emilian Dudas (CPhT, Palaiseau)
* Lepton flavors & neutrinos - Martin Hirsch (IFIC, Valencia)
* QCD/jets - Gavin Salam (LPTHE, Paris / CERN / Princeton)
* Heavy ions - François Gelis (IPhT, Saclay)
* Quark flavors & lattice - Laurent Lellouch (CPT, Marseille)
* Dark matter & astroparticles - Malcolm Fairbairn (King's College, London)


Comité scientifique / Scientific committee
D. Becirevic (LPT Orsay)
G. Bélanger (LAPTH Annecy)
J. Charles (CPT Marseille)
A. Deandrea (IPN Lyon)
C. Deffayet (APC Paris)
E. Dudas (CPhT Palaiseau)
P. Fayet (LPTENS Paris)
B. Fuks (IPHC Strasbourg)
Th. Gousset (Subatech Nantes)
M. Klasen (LPSC Grenoble)
G. Moultaka (L2C Montpellier)
J. Orloff (LPC Clermont-Ferrand)
G. Salam (LPTHE Jussieu)
G. Servant (IPhT Saclay)
C. Volpe (IPN Orsay)

Comité local / Local committee
Michele Frigerio (L2C)
Cyril Hugonie (LUPM)
Jean-Loïc Kneur (L2C)
Julien Lavalle (LUPM)
Gilbert Moultaka (L2C)
Stephan Narison (LUPM)

Secrétariat / Secretary
Michèle Delpont (L2C)
Emmanuelle Martinez (LUPM)

Participants
• Akin Wingerter
• Albert Villanova del Moral
• Alfonso Sastre
• Alfredo Urbano
• Ali N. khorramian
• Ana M. Teixeira
• Antoine Gérardin
• Antonin Portelli
• Bruno Machet
• Béranger DUMONT
• Cedric Weiland
• Christopher Smith
• Cyril Hugonie
• David Greynat
• Dirk Zerwas
• Dumitru Ghilencea
• elisa meunier
• Emilian Dudas
• Emmanuel NEZRI
• Enrico Bertuzzo
• Fernand Michel Renard
• Florian Lyonnet
• Francois Gelis
• Gavin Salam
• Genevieve Belanger
• Gilbert Moultaka
• Gregory Vulvert
• Grégory Espitalier Noël
• Guillaume Drieu La Rochelle
• Ingo Schienbein
• Jean Orloff
• Jean-Loic Kneur
• Jean-Philippe Guillet
• Jonathan Da Silva
• Julien Frison
• Julien Lavalle
• Konstantin Petrov
• Laurent Lellouch
• Malcolm Fairbairn
• Marc KNECHT
• Martin Hirsch
• Michaël Ughetto
• michel capdequi peyranere
• Michele Frigerio
• Nejc Košnik
• Nicolas Garron
• philippe brax
• Pierre Grange
• Quentin Le Boulc'h
• Stephan Narison
• Thomas Epelbaum
• Tomas Jezo
• Yacine Mehtar-Tani
Contact
• lundi, 14 mai
• 09:00 09:45
Accueil et inscription / Welcome and registration 45m bât. 7, UM2

#### bât. 7, UM2

• 09:45 10:00
Mot de bienvenue / Welcome address 15m Amphi IAE, bât 29 (UM2)

### Amphi IAE, bât 29

#### UM2

Orateur: The LOC
• 10:00 11:05
Flavors Amphi IAE, bât 29 (UM2)

### Amphi IAE, bât 29

#### UM2

• 10:00
Lepton flavour violation and neutrinos (review talk) 40m Amphi IAE, bât 29

### Amphi IAE, bât 29

#### UM2

Orateur: Dr Martin Hirsch (IFIC/CSIC, Universidad Valencia)
• 10:40
Theta 13 after Daya Bay 25m Amphi IAE, bât 29

### Amphi IAE, bât 29

#### UM2

The lepton mixing angle theta 13, the only unknown angle in the standard three-flavor neutrino mixing scheme, is finally measured by recent reactor and accelerator experiments. We perform a combined analysis of the data coming from T2K, MINOS , Double Chooz, and Daya Bay, extracting a 6.2 sigma significance for nonzero theta 13. We also discuss near future expectations on the precision of the theta 13 determination.
• 11:05 11:30
Pause café / Coffee break 25m Amphi IAE, bât 29 (UM2)

### Amphi IAE, bât 29

#### UM2

• 11:30 12:45
Flavors Amphi IAE, bât. 29 (UM2)

### Amphi IAE, bât. 29

#### UM2

• 11:30
Fitting neutrino physics with a U(1)_R lepton number 25m
Orateur: Dr Enrico Bertuzzo (IPHT-CEA Saclay)
• 11:55
Lepton flavour violation at the LHC in SUSY seesaw type-I 25m
Orateur: Dr Albert Villanova del Moral (LUPM Montpellier)
• 12:20
A Minimal Model of Neutrino Flavor 25m
N.N.
Orateur: Dr Akin Wingerter (LPSC)
• 12:45 14:30
Pause déjeuner / Lunch break 1h 45m Restaurant administratif (UM2)

#### UM2

• 14:30 16:25
Flavors Amphi IAE, bât. 29 (UM2)

### Amphi IAE, bât. 29

#### UM2

• 15:10
Lattice computation of $K\to\pi\pi$ amplitudes 25m Amphi IAE, bât. 29

### Amphi IAE, bât. 29

#### UM2

Orateur: Dr Nicolas Garron (university of Edinburgh)
• 15:35
Isospin breaking corrections to light hadron masses 25m Amphi IAE, bât. 29

### Amphi IAE, bât. 29

#### UM2

Orateur: M. Antonin Portelli (Centre de Physique Théorique (CPT))
• 16:00
Probing $N_f=2$ chiral dynamics with topological zero-modes in the mixed chiral regim 25m Amphi IAE, bât. 29

### Amphi IAE, bât. 29

#### UM2

Lattice QCD benefits nowadays from numerous progess thanks to algorithmic enhancements to push down the quark masses to reach the physical masses and to increase the lattice geometry to avoid finite volume effects. However using fermions which do not break the chiral symmetry both in valence and sea sector is still a challenge. An alternative is to consider mixed action simulations, where one uses for example Ginsparg-Wilson respecting chiral symmetry to describe the valence quark whereas the sea is described by Wilson fermions, which break chiral symmetry and which are numerically cheaper but even in this case, using large volumes do avoid finite-volume effects is rather expensive. Chiral perturbation theory (ChPT) can be done in finite-volume so that it can take into account the finite-volume effects. But we can use quarks that do not belong to the same chiral regime : some quarks can be in the so-called epsilon regime of ChPT which allows to compute large finite-size effects while other quarks are in the usual p regime. We thus consider a theory with $N_v$ quarks in the epsilon regime and $N_s$ quarks in the p-regime. These results can be used to match lattice QCD and the chiral effective theory in a large but finite box in which the Compton wavelength of the lightest pions is of the order of the box size. This approach allows us to test the chiral regime. I will present some results obtained in the case of the PP correlator.
Orateur: Dr Gregory Vulvert (IFIC Valencia)
• 16:25 16:50
Pause café / Coffee break 25m Amphi IAE, bât 29 (UM2)

### Amphi IAE, bât 29

#### UM2

• 16:50 18:20
Higgs boson(s) Amphi IAE, bât 29 (UM2)

### Amphi IAE, bât 29

#### UM2

• 16:50
Higgs and things (review talk) 40m Amphi IAE, bât 29

### Amphi IAE, bât 29

#### UM2

Orateur: Dirk Zerwas (LAL Orsay)
• 17:30
Implications of a 125 GeV Higgs 25m Amphi IAE, bât 29

### Amphi IAE, bât 29

#### UM2

Orateur: Dr Abdelhak Djouadi (LPT Orsay)
• 17:55
A Higgs signal Beyond the MSSM 25m Amphi IAE, bât 29

### Amphi IAE, bât 29

#### UM2

The BMSSM (Beyond the MSSM) framework is an effective theory approach that encapsulates a variety of extensions beyond the MSSM with which it shares the same field content. The lightest Higgs mass can be much heavier than in the MSSM without creating a tension with naturalness or requiring superheavy stops. The phenomenology of the Higgs sector is at the same time much richer. I discuss here the different predicted rates in the LHC channels ZZ->4l, 2 photons, 2 photons + 2 jets and WW, together with the constraint stemming from the non observation of other Higgses in all channels. A special stress is put on the correlations between the signal channels and how they can help to exclude or discriminate among different theoretical models. I show furthermore how those results behave when applying constraints from dark matter and flavour physics.
Orateur: M. Guillaume Drieu La Rochelle (LAPTH)
• mardi, 15 mai
• 09:30 11:00
Astroparticle physics and cosmology Salle des actes, bât. 7 (UM2)

### Salle des actes, bât. 7

#### UM2

• 09:30
Dark stuff (review talk) 40m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

I will (extremely) briefly review the evidence for dark matter and then the ongoing efforts to detect it using indirect and direct detection. I will talk about recent developments in indirect detection including a couple of potential signals from Fermi and some recent pessimistic predictions from N-body simulations. I will then review the ongoing search for dark matter via direct detection. I will explain the astrophysical uncertainties in direct detection and estimate their errors. If I have time I will mention the situation in the world of dark energy and some recent work in this area.
Orateur: Dr Malcolm Fairbairn (King's College London)
• 10:10
Neutralino relic density with Next to Leading Order (co)annihilation cross-section 25m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

The relic density of Dark Matter in the Universe imposes today one of the most stringent constraints on new physics models such as the Minimal Supersymmetric Standard Model (MSSM). The most recent analysis of the WMAP collaboration has already reached an accuracy of 3%, and the upcoming results obtained with the Planck satellite will be even more precise. It is therefore mandatory for the theoretical predictions to match this impressive experimental precision. An important contribution to the theoretical uncertainty of the relic density comes from higher-order corrections to the Dark Matter annihilation and coannihilation cross sections. The DM@NLO ("Dark Matter at Next to Leading Order") project aims at providing a numerical code to compute these cross sections for the lightest neutralino at NLO in the strong coupling. All relevant corrections to the annihilation of two neutralinos into quark-antiquark pairs have already been included and have been shown to modify significantly the predicted relic density. Neutralino-chargino and neutralino-squark coannihilation processes are in progress. In this presentation I will first recall the motivations for a high-precision calculation of the relic density and show typical numerical results for neutralino annihilation into quarks. I will then give a general overview of the DM@NLO project and discuss in some detail the specific case of neutralino-squark coannihilation.
Orateur: M. Quentin Le Boulc'h (LPSC)
• 10:35
Mixed sneutrino dark matter in light of recent experimental results 25m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

Orateur: Béranger DUMONT (LPSC Grenoble)
• 11:00 11:30
Pause café / Coffee break 30m bât. 7 (UM2)

### bât. 7

#### UM2

• 11:30 12:45
Astroparticle physics and cosmology Salle des actes, bât. 7 (UM2)

### Salle des actes, bât. 7

#### UM2

• 11:30
Probing the supersymmetric inflaton and dark matter link 25m
In this talk I will present a study on the NUHM2 supersymmetric model where both the cosmic inflation and the observed dark matter abundance can be explained, with a Higgs boson mass in the range favoured by the latest LHC data. The two inflaton candidates LLe and udd are embedded within the MSSM therefore their decay naturally excites all the relevant degrees of freedom which thermalizes the lightest supersymmetric particle (LSP) during reheating. Many configurations in the NUHM2 parameter space predict the correct relic density for the LSP, the right amplitude and tilt of the power spectrum. We find also that the dark matter interactions with XENON nuclei fall within the projected range for XENON1T. Hence, such a scenario will be significantly constrained by this experiment.
Orateur: M. Jonathan Da Silva (Laboratoire d'Annecy-Le-Vieux de Physique Théorique)
• 11:55
Neutrinos are not in a rush 25m
I will describe how neutrinos could go faster than the speed of light in a dense environment if gravity were modified by a scalar field. I will show that the speed difference would almost always be unobservable for natural values of the couplings of scalars to matter.
Orateur: Dr philippe brax (IPHT Saclay)
• 12:20
Lepton flavour violation in the inverse seesaw 25m
The inverse seesaw is a very appealing mechanism to generate neutrino masses since it provides natural neutrino Yukawa couplings ($Y_\nu \sim O(1)$) and a seesaw scale close to the electroweak one, thus within LHC reach. In a previous work (arXiv:1111.5836) where we embedded the inverse seesaw in a supersymmetric extension of the Standard Model (MSSM), we have highlighted that the Higgs-mediated penguin diagrams contributing to lepton flavour violating observables like $\tau \rightarrow \mu \mu \mu$ or $B_{d}^{0} \rightarrow e \mu$ are enhanced by as much as two orders of magnitude. It has recently been pointed out (arXiv:1202.1825) that the Z-mediated contributions could be enhanced in extensions of the MSSM that accommodate neutrino masses, the supersymmetric inverse seesaw being one of them. This work is devoted to a comprehensive study of several LFV observables (mu-e conversion, \mu \rightarrow 3 e, \tau \rightarrow \mu \eta, etc) and their enhancements due to the effect of the inverse seesaw. It allows us to put new constraints on this model, given the present experimental bounds on these observables. Furthermore, LFV observables which are dominated by the Z- mediated contribution exhibit specific behaviour like a reduced dependence on the supersymmetric parameters or on the right-handed neutrino masses.
Orateur: Cedric Weiland (LPT Orsay)
• 12:45 14:30
Pause déjeuner / Lunch break 1h 45m Restaurant administratif (UM2)

#### UM2

• 14:30 16:25
Heavy ions Salle des actes, bât. 7 (UM2)

### Salle des actes, bât. 7

#### UM2

• 14:30
Heavy ions (review talk) 40m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

Orateur: Dr Francois Gelis (IPhT)
• 15:10
Jet evolution in the QGP 25m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

We study the perturbative evolution of a jet via multiple gluon emissions induced by the interactions between the jet constituents and a dense QCD medium like a quark-gluon plasma. We focus on the typical medium-induced gluon emissions, for which the gluon formation time is much smaller than the overall size of the medium. We show that the typical time between two subsequent emissions is parametrically larger than the formation time for one gluon (in contrast to jet fragmentation in the vacuum, where these two scales get identified with each other). This separation of scales has a remarkable physical consequence: it implies that coherence phenomena are negligible and therefore successive emissions can be treated as independent from each other and ordered in time. This is important as it allows for a probabilistic interpretation of the in-medium jet fragmentation as a classical branching process, which is in particular suitable for implementation as an event generator.
Orateur: Dr Yacine Mehtar-Tani (IPhT)
• 15:35
Thermalization in scalar field theories 25m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

The quark gluon plasma thermalization in heavy ion collisions is an open problem that gave rise to many works in recent years. One of the approaches developped to study this QCD non pertubative problem is a resummation scheme that amounts to averaging over classical fields with random initial conditions. Its numerical implementation is presented here in the case of a scalar field theory with a quartic coupling, that shares some important features with QCD (scale invariance at the classical level and the presence of instabilities). In particular, we will show the relevance of this resummation in capturing the physics relevant for thermalization.
Orateur: M. Thomas Epelbaum (IPhT)
• 16:00
Symmetries and currents of the ideal and the unitary Fermi gases 25m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

The maximal algebra of symmetries of the free Schrodinger equation is determined. This algebra is an infinite dimensional extension of the Schrodinger algebra (by higher symmetries which are not kinematical transformations), it is isomorphic to the Weyl algebra of quantum observables, and it may be interpreted as a non-relativistic higher-spin algebra. The associated infinite collection of Noether currents bilinear in the fermions are derived from their relativistic counterparts via a light-like dimensional reduction.
Orateur: elisa meunier (LMPT)
• 16:25 17:00
Pause café / Coffee break 35m bât. 7 (UM2)

### bât. 7

#### UM2

• 17:00 18:30
Table ronde /Discussion session Salle des actes, bât. 7 (UM2)

### Salle des actes, bât. 7

#### UM2

Présidents de session: Dr Genevieve Belanger (LAPTH) , Prof. Jean Orloff (LPC Clermont-Ferrand IN2P3/CNRS Univ. Blaise Pascal France) , Dr philippe brax (IPHT Saclay)
• 19:45 23:00
Dîner / Social dinner 3h 15m Restaurant la Diligence (+33 (0)4 67 66 12 21) (2, Place Pétrarque, Montpellier)

### Restaurant la Diligence (+33 (0)4 67 66 12 21)

#### 2, Place Pétrarque, Montpellier

• mercredi, 16 mai
• 09:30 11:00
Beyond the Standard Model Salle des actes, bât. 7 (UM2)

### Salle des actes, bât. 7

#### UM2

• 09:30
Physics beyond the Standard Model (review talk) 40m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

Orateur: Dr Emilian Dudas (Ecole Polytechnique)
• 10:10
LHC phenomenology of general SU(2)xSU(2)xU(1) models 25m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

General SU(2)xSU(2)xU(1) models represent a well-motivated intermediate step towards the unification of the Standard Model gauge groups. Based on a recent global analysis of low-energy and LEP constraints of these models, we perform numerical scans of their various signals at the LHC. We show that total cross sections for lepton and third-generation quark pairs, while experimentally easily accessible, provide individually only partial information about the model realized in Nature. In contrast, correlations of these cross sections in the neutral and charged current (CC) channels may well lead to a unique identification.
Orateur: M. Tomas Jezo (LPSC)
• 10:35
Ultraviolet clues from infrared fingerprints 25m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

Orateur: M. Alfredo Urbano (Department of Physics and INFN, University of Salento)
• 11:00 11:30
Pause café / Coffee break 30m bât. 7 (UM2)

### bât. 7

#### UM2

• 11:30 12:45
Beyond the Standard Model Salle des actes, bât. 7 (UM2)

### Salle des actes, bât. 7

#### UM2

• 11:30
Baryon and lepton number violation at the LHC 25m
Baryon (B) and lepton (L) numbers are conserved in the standard model lagrangian, but generally not in new physics models. In this talk, we adopt an effective approach to analyze, in a model-independent way, the possible signatures of B and L violating interactions at the LHC. Then, we particularize the discussion to the minimal supersymmetric standard model, where such interactions may now be much welcome since they allow to bypass the already tight constraints on sparticle masses.
Orateur: Dr Christopher Smith (IPN Lyon)
• 11:55
Unlocking the Standard Model : the 1-generation case 25m
I show that the Standard Model of weak interactions cannot have less than two Higgs doublets as soon as they are considered (to transform) as $\bar q_i q_j$ and $\bar q_i \gamma_5 q_j$ bilinears. There are exactly two for one generation of quarks, which is the simple case under scrutiny here. All basic physical properties, not only of massive gauge bosons, but also of fermions and J=0 mesons are correctly described. Re-written in this way, the Standard Model appears to be complete'' in the sense that no extra physics, no heavy fermion nor any additional interaction is needed to calculate the mass of the second Higgs bosons, which appears as a suitable dark matter candidate.
Orateur: Dr Bruno Machet (CNRS)
• 12:20
Indirect dark matter signals and backgrounds in cosmological simulations 25m
Orateur: Dr Emmanuel NEZRI (LAM CNRS)
• 12:45 14:30
Déjeuner / Lunch break 1h 45m Restaurant administratif (UM2)

#### UM2

• 14:30 16:25
QCD (dans tous ses états) Salle des actes, bât. 7 (UM2)

### Salle des actes, bât. 7

#### UM2

• 14:30
QCD in hadron collisions (review talk) 40m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

Orateur: Dr Gavin Salam (LPTHE Jussieu)
• 15:10
Model independent view of $b \to s l^- l^+$ 25m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

We discuss the advantages of combining the experimental bound on B(Bs->mu+ mu-) and the measured B(B->Kl+l-) to get the model independent constraints on physics beyond the Standard Model. Since the two decays give complementary information, one can study not only the absolute values of the Wilson coefficients that are zero in the Standard Model, but also their phases. We also emphasize the importance of measuring the forward-backward asymmetry in B->Kl+l- decay at large q2's.
Orateur: Dr Nejc Kosnik (Laboratoire de l'accelerateur lineaire)
• 15:35
Reconstruction of non-analytic functions 25m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

With the help of the Mellin-Barnes transform, we show how to simultaneously resum the expansion of any kind of non-analytic functions around 0, 1 and $infinity$ in a systematic way. We exemplify the method for the perturbative vector, axial scalar and pseudo-scalar correlator at $\mathcal{O}(\alpha_s^{3})$. We show that the coefficients, $\Omega(n)$, of the Taylor expansion of the vacuum polarization function in terms of the conformal variable $\omega$ admit, for large $n$, an expansion in powers of $1/n$ (up to logarithms of $n$) that we can calculate exactly. This large-$n$ expansion has a sign-alternating component given by the logarithms of the OPE, and a fixed-sign component given by the logarithms of the threshold expansion in the external momentum $q^2$.
Orateur: Dr David GREYNAT (Fisica Teorica - Uni. de Zaragoza)
• 16:00
Strong coupling constant from first principles 25m Salle des actes, bât. 7

### Salle des actes, bât. 7

#### UM2

Orateur: Konstantin Petrov (LAL)
• 16:25 16:30
Conclusion, end of RPP-2012 Salle des actes, bât. 7 (UM2)

### Salle des actes, bât. 7

#### UM2

• 16:30 17:00
Café de clôture / "Closing" coffee 30m bât. 7 (UM2)

### bât. 7

#### UM2

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