PLANCK 2011 - From the Planck Scale to the ElectroWeak Scale
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Main Auditorium (IST Congress Centre)
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REGISTRATION CERN
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Welcome Main Auditorium
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Coffee Break IST Congress Center
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RECEPTION IST Congress Center
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P1 - FLAVOUR SYMMETRIES Main Auditorium
Main Auditorium
IST Congress Centre
Convener: Andrea Romanino-
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D14 - a symmetry for quarks and leptonsWe construct a model in the framework of the MSSM in which the dihedral group D14 plays the role of the flavour symmetry. We show that in the quark sector the Cabibbo angle is predicted, |V_ud|=cos(pi/14), and at the same time mu-tau symmetric mixing in the neutrino sector. The solar mixing angle is expected to be large. Charged fermion mass hierarchies are explained. The spectrum of light neutrinos is normally ordered with m1=0.Speaker: Claudia Hagedorn (INFN, Section of Padua)
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Connections between family symmetry invariants and neutrino phenomenologyTribimaximal leptonic mixing is a mass-independent mixing scheme. By decomposing the associated effective neutrino mass matrix, we derive generic predictions in terms of the parameters governing the neutrino masses. We extend this phenomenological analysis to other mass-independent mixing schemes. We classify models that produce tribimaximal leptonic mixing through the group structure of their family symmetries in order to point out that there is often a direct connection between the group structure and the phenomenological analysis.Speaker: Ivo de Medeiros Varzielas (TU Dortmund)
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Phenomenological impact of flavour symmetriesFlavour symmetries have been widely studied to account for the Flavour Problem. Successful flavour models provide an explanation for the observed pattern of fermion masses and mixings, independently on the type of the implemented symmetry (either local or global, either discrete or continuous, either Abelian or non-Abelian). In order to distinguish among different constructions and to confirm or rule out some of them, detailed phenomenological analyses are necessary. In this talk I illustrate recent results on the phenomenological impact of flavour symmetries.Speaker: Dr Luca Merlo (Technische Universitat Munchen)
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Nearest-Neighbour-Interactions from a minimal discrete flavour symmetry within SU(5) Grand UnificationA flavour symmetry based on Z_4 is developed in the context of SU(5) Grand Unification with the standard fermionic content plus three right-handed neutrinos. It is demanded for Z_4 to forbid some Yukawa couplings of up- and down-quarks to Higgs scalars so that the quark mass matrices M_u, M_d have Nearest-Neighbour-Interaction (NNI) structure, once they are generated through the electroweak symmetry breaking. The implementation of Z_4 requires the introduction of at least two Higgs quintets, which leads to a two Higgs doublet model at low energy scale. Due to the SU(5) unification, it is shown that the charged lepton mass matrix has also NNI form. However, the effective neutrino mass matrix exhibits a non parallel pattern, because of the type-I seesaw mechanism. Analysing all possible texture zeroes allowed by gauge-horizontal symmetry SU(5)xZ_4, it is seen that only two patterns are in agreement with the leptonic experimental data and they could be further distinguished by the light neutrino mass spectrum hierarchy.Speaker: Catarina Simões (CFTP - IST)
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Right unitarity triangles and tri-bimaximal mixingWe propose new classes of models which predict both tri-bimaximal lepton mixing and a right-angled CKM unitarity triangle, alpha approximately 90 degrees. The ingredients of the models include a supersymmetric unified gauge group such as SU(5), a discrete family symmetry such as A4 or S4, a shaping symmetry including products of Z2 and Z4 groups as well as spontaneous CP violation. We show how the vacuum alignment in such models allows a simple explanation of alpha approximately 90 degrees by a combination of purely real or purely imaginary vacuum expectation values of the flavons responsible for family symmetry breaking. This leads to quark mass matrices with 1-3 texture zeros that satisfy the phase sum rule and lepton mass matrices that satisfy the lepton mixing sum rule together with a new prediction that the leptonic CP violating oscillation phase is close to either 0, 90, 180, or 270 degrees depending on the model, with neutrino masses being purely real (no complex Majorana phases). This leads to the possibility of having right-angled unitarity triangles in both the quark and lepton sectors.Speaker: Christoph Luhn (University of Southampton)
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Naturally large Yukawa hierarchiesThe spontaneous breaking of the $SU(3)^5$ quark/lepton flavor symmetry by means of three multiplets of `Yukawa scalar fields' admits vacua with one $O(1)$ and two vanishing vevs for each multiplet. With three generations, and only in this case, the vanishing entries are lifted to exponentially suppressed values by the addition of symmetry invariant logarithmic terms. A strong hierarchy for the Yukawa couplings and an approximately diagonal quark mixing matrix are generated in a natural way from order one parameters. This scenario also provides a concrete realization of the minimal flavour violation hypothesis.Speaker: Dr Enrico Nardi (INFN-LNF)
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P2 - EXTRA DIMENSIONS VA3 (IST Congress Center)
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Convener: Michael Ratz (Technische Universitaet Muenchen)-
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Ultra visible warped models at hadron collidersWe present a class of warped models where the SM flavor hierarchies are determined by UV physics. These Flavor Triviality (FT) models display a sweet-spot of parameters where a KK-gluon mass as low as O(2)TeV is consistent with EWPTs. In contrast with the so-called anarchic warped models, FT models show no tension with either FCNCs or EDMs, while naturalness is potentially improved. Furthermore, FT warped models exhibit new exciting phenomenology at hadron colliders. At the Tevatron frontier, we show that they can naturally account for the dimuon anomaly in B decays and a sizable forward-backward asymmetry in t-tbar production, as recently reported by both CDF and D0. Also, the discovery potential of a warped extra dimension at the early LHC is significantly improved compared to the anarchic case, as the KK-gluon production cross section in FT models can be as large as few picobarns.Speaker: cedric delaunay (Weizmann Institute of Science)
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The bottom and top quarks in warped models : LHC predictions from LEP/Tevatron anomaliesSince a decade, there have been extensive developments about an alternative to supersymmetry: the scenarios with warped extra dimensions. Those constitute a new paradigm in the sense that they are dual, through the AdS/CFT correspondence, to composite Higgs models. These scenarios predict naturally strong deviations from the Standard Model mainly in the bottom and top quark sector. In that sense, the LEP anomaly on Forward-Backward bottom asymmetry (A^b_FB) and the recent Tevatron anomalies on the top asymmetry (A^t_FB) could be interpreted as early signatures of the warped models. We will discuss warped model realizations allowing to explain both A^b_FB and A^t_FB [measured as a function of the ttbar invariant mass and the top rapidity], taking into account the constraints issued from dijet production rates at LHC. The other constraints from the measurements of top pair production cross section sigma_ttbar at LHC will be studied. Then, I will describe what are the predictions of these warped models at LHC, pointing out the complementarity between Tevatron and LHC on top physics. There are typically two types of predicted signatures at LHC: a resonance peak in the ttbar invariant mass distribution (due to the exchange of a Kaluza-Klein excitation of the gluon) or the production of exotic colored fermions around a few hundred's of GeV. The results presented here are based on some of our previous studies as well as on a work in progress.Speaker: Dr Grégory Moreau (LPT/University Paris 11, France)
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Consistent MUED for the LHCWe revisit the Minimal Universal Extra Dimensions (MUED) model by implementing consistently electroweak symmetry breaking and loop-corrections in five dimensions. I will present the detailed spectrum as well as some production chanels at the LHCSpeaker: Chloé Papineau
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A 5D Model of Baryons and MesonsUsing the prescriptions of the AdS/CFT correpondence it is possible to build Extra Dimensional models that describe low energy hadrons. I will review a simple 5D model of QCD in which mesons are represented by bulk fields and baryons arise as solitons, in analogy to the original Skyrme model. Contrary to 4D Skyrmions, however, baryon physics is calculable in this effective description, so it provides a useful framework for computing nucleon properties. This holographic model also describes pion masses and anomalies due to the addition of a 5D scalar and the Chern-Simons term.Speaker: Mr Oriol Domenech (IFAE, Barcelona)
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Warped de Sitter compactificationsWe show that the warped de Sitter compactification is possible under certain conditions in D-dimensional gravitational theory coupled to a dilaton, a form field strength, and a cosmological constant. We find that the solutions of field equations give de Sitter spacetime with the warped structure. We also discuss the dynamics of moduli in the lower-dimensional effective theories and show that the internal space moduli can be fixed by the flux if the indices of non-vanishing components of the field strength could be along the internal space.Speaker: Dr Kunihito Uzawa (Kindai University)
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Seesaw in the bulkA five-dimensional seesaw framework is analyzed with the lepton-number-violating propagator of bulk right-handed neutrinos. That can bypass summing up the effects of heavy Majorana particles whose masses and wavefunctions are not exactly known. The propagator method makes it easier to evaluate the seesaw-induced neutrino mass for various boundary conditions of bulk neutrinos and in a general background geometry, including the warped extra dimension. It is also found that the higher-dimensional seesaw gives a natural framework for the inverse seesaw suppression of low-energy neutrino masses. With the introduction of the discrete flavor symmetries, the boundary conditions of the bulk neutrinos trigger feasible symmetry breaking to account for the observed pattern of the neutrino masses and mixing.Speaker: Dr Atsushi Watanabe (Niigata Univ.)
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Neutrino Mass from a Mini-SeesawThe Mini-Seesaw mechanism combines naturally suppressed Dirac and (sterile) Majorana mass scales together in a low-scale seesaw to achieve light Standard Model neutrino masses. A key feature of this approach is the existence of a tower of light sterile neutrinos, all of which can mix with the Standard Model. We will detail this mechanism and discuss the prospects for observing the light sterile modes.Speaker: Kristian McDonald (Max Planck Institute (Heidelberg))
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P3 – STRINGS, GRAVITY & HOLOGRAPHY VA4
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IST Congress Centre
Convener: Fernando Marchesano Buznego (Unknown)-
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Reduction of N=1, E8 SYM over SU(3)/U(1)xU(1)xZ3 and its four-dimensional effective actionWe propose an extension of the Standard Model inspired by the E_8 x E_8 Heterotic String. In order that a reasonable effective Lagrangian is presented we neglect everything else other than the ten-dimensional N=1 supersymmetric Yang-Mills sector associated with one of the gauge factors and certain couplings necessary for anomaly cancellation. We consider a compactified space-time M_4 x B_0/Z_3, where B_0 is the nearly Kaehler manifold SU(3)/U(1) x U(1) and Z_3 is a freely acting discrete group on B_0. Then we reduce dimensionally the E_8 on this manifold and we employ the Wilson flux mechanism leading in four dimensions to an SU(3)^3 gauge theory with the spectrum of a N=1 supersymmetric theory. We compute the effective four-dimensional Lagrangian and demonstrate that an extension of the Standard Model is obtained with interesting features including a conserved baryon number and fixed tree level Yukawa couplings and scalar potential. The spectrum contains new states such as right handed neutrinos and heavy vector-like quarks.Speaker: Prof. Nikos Irges (NTUA)
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Sequestering by global symmetries in Calabi-Yau string modelsI will report on a study of the possibility of realizing an effective sequestering mechanism between visible and hiden sectors in generic Calabi-Yau heterotic string models, which would ensure an approximate universality of soft scalar masses as a consequence of a global symmetry. I will focus on the brane-to-brane effects that are related to effective interactions involving four matter fields in the effective Kahler potential. I will outline how these contact terms can be computed and describe what is their geometric interpretation, emphasizing the differences with the case of orbifolds. I will then discuss under which conditions there exist suitable global symmetries that could be imposed to the unknown effective superpotential in such a way to ensure the vanishing of the corresponding unwanted tree-level contribution to soft scalar masses.Speaker: Claudio Scrucca (Institute for Theoretical Physics, EPFL)
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How Grand Unification is realized in String Theory?The structure of the Standard Model strongly suggests that it is embedded into Grand Unification based on groups of E_n series. Compactification of string theory naturally realise such relation yielding the gauge group, matter spectrum and Yukawa interactions. We focus on SU(3)xSU(2)xU(1) embedding of Standard Model in F-theory and learn features contrasted to field theoretic unification.Speaker: Kang Sin Choi (Korea Institute for Advanced Study)
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Weak Mixing Angle and Proton Stability in F-theory GUTIt is pointed out that a class of flipped SU(5) models based on F-theory naturally explains the gauge coupling unification. It is because the group SU(5) x U(1)_X is embedded in SO(10) and E_8. To prohibit the dimension 4 and 5 proton decay processes, the structure group should be SU(3) or smaller. Extra heavy vector-like pairs of {5_{-2},5*_2} except only one pair of Higgs should be also disallowed, because they could induce the unwanted dimension 5 proton decays. We construct a simple global F-theory model considering these points. To maintain sin^2 theta_W^0 = 3/8 at the GUT scale, the fluxes are turned-on only on the flavor branes.Speaker: Prof. Bumseok Kyae (Pusan National Univ.)
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Low energy physics of a F-theory GUT modelI shall discuss a GUT model inspired by recent local F-theory constructions. The model has extra matter which after switching vev play the role of messengers. The resulting model does not lead to unacceptable baryon/lepton number violating processes. SUSY is broke at a hidden sector. I shall discuss the resulting spectrum of the lightest SUSY particles and some phenomenological consequences of thereof.Speaker: Jacek Pawelczyk (University of Warsaw)
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Warming up brane-antibrane inflationWe show that, in constructions with additional intersecting D-branes, brane-antibrane inflation may naturally occur in a warm regime, such that strong dissipative effects damp the inflaton's motion, greatly alleviating the associated eta-problem. We illustrate this for D3-antiD3 inflation in flat space with additional flavor D7-branes, where for both a Coulomb-like and a quadratic potential a sufficient number of e-folds may be obtained for perturbative couplings and O(10-100) branes. This in clear contrast with the corresponding cold scenarios, thus setting the stage for more realistic constructions within fully stabilized compactifications. Such models generically predict a negligible amount of tensor perturbations and non-gaussianity f_NL~O(10).Speaker: Dr Joao Rosa (University of Edinburgh)
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Coffee Break Main Auditorium
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P4 - SUPERSYMMETRY Main Auditorium (IST Congress Center)
Main Auditorium
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Convener: Stephane Lavignac-
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Decoupling the Gravity Multiplet from SupergravityThe full machinery of supergravity (SUGRA) is required to understand many SUSY models. For the purposes of understanding phenomenology at colliders and in cosmology, though, the main concern is to ascertain the effects of SUGRA on the vacuum structure and particle spectrum. Practical SUGRA calculations often require cumbersome manipulations of component field terms involving the full gravity multiplet. In this talk, I will present an alternative gauge fixing for conformal SUGRA which decouples these gravity complications from SUGRA computations. This yields a simplified tree-level action for the matter fields in SUGRA which can be expressed compactly in terms of superfields and a modified conformal compensator. As a concrete application, I will show how this new gauge fixing makes it possible to cleanly calculate the mass spectrum of goldstini arising from a general admixture of F-term, D-term, and almost no-scale supersymmetry breaking.Speaker: Francesco D'Eramo (MIT)
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Condensates and R-balls in the SUSY breaking sectorFlat directions in the MSSM have long been used to generate a large baryon number asymmetry via the Affleck-Dine mechanism. In a complete theory that includes SUSY breaking it is unlikely they are alone. Renormalisable O'Raifeartaigh models also possess flat directions that can carry R-charge. I will discuss the cosmological consequences of these fields and the possible formation of large, classical objects: R-balls.Speaker: Mr James Barnard (Durham University)
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Goldstino Couplings in MSSMLow energy (multi-TeV) supersymmetry breaking is an interesting possibility since it alleviates the little hierarchy problem in a natural and minimal way. This scenario generally predicts an almost massless gravitino whose dynamics are effectively described by its goldstino component. Focusing on the Minimal Supersymmetric Standard Model, the corresponding effective theory would be that of MSSM plus goldstino. We construct the most general effective Lagrangian by using the constrained superfields formalism and comment on its phenomenological consequences.Speaker: Pantelis Tziveloglou (Ecole Polytechnique)
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Singlet deflection of gauge mediationThe NMSSM is embedded into gauge mediation adding direct couplings between the singlet, the higgs and the messenger. In this way sizable contributions to trilinear couplings are generated and a viable spectrum with sparticles at the TeV scale or below is generated.Speaker: Antonio Delgado (University of Notre Dame)
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Lopsided Gauge MediationThe unavoidable tuning among supersymmetric parameters required to raise the Higgs boson mass beyond its experimental limit opens up new avenues for dealing with the so called $\mu$-$B_\mu$ problem of gauge mediation. In fact, it allows for accommodating, with no further parameter tuning, large values of $B_\mu$ and of the other Higgs-sector soft masses, as predicted in models where both $\mu$ and $B_\mu$ are generated at one-loop order. This class of models, called Lopsided Gauge Mediation, offers an interesting alternative to conventional gauge mediation and is characterized by a strikingly different phenomenology, with light higgsinos, very large Higgs pseudoscalar mass, and moderately light sleptons.Speaker: Mr Duccio Pappadopulo (EPFL)
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Supersymmetry Breaking in a Minimal Anomalous Extension of the MSSMWe study a supersymmetry breaking mechanism in the context of a minimal anomalous extension of the MSSM (arXiv:1102.5040). The anomaly cancellation mechanism is achieved through the Green-Schwarz mechanism. We assume that the standard MSSM superpotential is perturbatively realized, except for the $\mu$-term which has a non-perturbative origin. The presence of this term is expected in many intersecting D-brane models which can be considered as the ultraviolet completion of our model. We show how soft supersymmetry breaking terms arise in this framework. Then we study the mass spectrum of the theory and the phenomenology of the new U(1)'s.Speaker: Dr Antonio Racioppi (NICPB)
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More minimal MRSSM: R symmetry as lepton number, sneutrino as down type higgsI will talk about a new R symmetric SUSY model where the R symmetry is identified with one of the lepton number, and as consequence the sneutrino plays the role of the down type Higgs. This is possible as the sneutrino does not carry any lepton number, and therefore the sneutrino VEV is not constrained by the usual tight bounds from the neutrino mass. On the other hand, all the other SUSY partners carry a lepton number, and this leads to a quite interesting and distinctive phenomelogy at colliders. Furthermore, our model has a more minimal particle content respect to the MRSSM (the Minimal R Symmetric Supersymmetric Standard Model): indeed we don’t need to enlarge the Higgs sector respect to the MSSM introducing an extra pair of doublets.Speaker: Ms Claudia Frugiuele (Carleton University)
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Solving $\mu$ and little hierachy problems of the MSSM with electroweak tripletsI will discuss a simple complete solution to both $\mu$ and the little hierarchy problems of the MSSM. This solution is achieved by combining MSSM with its two well known extensions. On the one side next-to-MSSM(NMSSM) can solve $\mu$ problem of the MSSM, but it is generically difficult to attain a tachyonic singlet required for this purpose, also addition of the singlet cannot increase significantly the prediction of the lightest CP-even Higgs mass (i.e., it does not solve the little hierarchy problem of the MSSM) in most of the region of parameter space. On the other side adding electroweak triplets (with non-zero hypercharge) to MSSM can solve the little hierarchy problem, but it creates an additional $\mu$ problem for the triplets. I will show that combination of the NMSSM and the model with SU(2) triplets may solve each others problems and I will discuss this combination in detail.Speaker: Aleksandr Azatov (University Of Rome "La Sapienza" and INFN sezione di Roma)
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Flavour physics as a probe of SUSY scenarios and implications of the LHCThe interplay of flavour and collider physics provides new opportunities for mapping possible routes beyond the SM. Flavour constraints play in this manner a complementary role to the direct searches. Here we present an overview of the existing flavour constraints on various models and show examples of the impact of the LHC results on a rather general framework for SUSY.Speaker: Nazila MAHMOUDI
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P5 - COSMOLOGY VA3 (IST Congress Center)
VA3
IST Congress Center
Convener: Nuno Miguel Santos (IST)-
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Phenomenology of a Pseudo-Scalar InflatonMany controlled realizations of inflation employ pseudo-scalar axions. Pseudo-scalars φ are naturally coupled to gauge fields through c φ F F~. In the presence of this coupling, gauge field quanta are copiously produced by the rolling inflaton. The produced gauge quanta, in turn, source inflaton fluctuations via inverse decay. These cosmological perturbations add incoherently with the “vacuum”perturbations, and are highly nongaussian. This provides a natural mechanism to generate large nongaussianity in single or multi field slow-roll inflation. The resulting phenomenological signatures are highly distinctive: large nongaussianity of (nearly) equilateral shape, in addition to detectably large values of both the scalar spectral tilt and tensor-to-scalar ratio. The WMAP bound on nongaussianity implies that the coupling c of the pseudo-scalar inflaton to any gauge field must be smaller than about 10^2 / M_p .Speaker: Prof. Marco Peloso (University of Minnesota)
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Higgs portal inflationWe consider the inflation model with non-minimal couplings where a singlet inflaton mixes with the Standard Model Higgs boson. The conditions required for the mixed inflation to happen constrain the Higgs and singlet couplings at unitarity scale, giving rise to additional constraints on the parameter space at low energy. We consider the LEP and electroweak precision data constraints on the singlet-mixed Higgs sector and discuss the implications of our analysis on the discovery potential of the Higgs bosons at colliders. We comment on the unitarity problems in our model.Speaker: Dr Hyun Min Lee (CERN)
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A possible solution to the supergravity eta problemThe destabilising effect of supergravity corrections on traditional inflaton potentials is well known. Here I will offer a possible solution based on the presense of an inflection point in the flat direction potential for some Kahler interaction terms. We show that for reasonable choices of the Kahler potential it is possible for a vacuum energy density with no dynamics of its own, to induce an extremely flat potential along the flat direction, and that this can be suitable for producing the observed inflation with a total fine tuning of no greater than one part in ten to the five.Speaker: Philip Stephens
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A Compelling Vector Curvaton Model and its Distinct Observational SignaturesA Compelling Vector Curvaton Model and its Distinct Observational SignaturesSpeaker: Jacques Wagstaff
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Technically natural dark energy from Lorentz breakingWe present a model of dark energy where the parameter setting the rate of cosmic acceleration has technically natural value, i.e. it does not receive corrections from other scales in the theory. The proposed acceleration mechanism appears generically in the low-energy limit of gravity with violation of Lorentz invariance and spontaneously broken internal global symmetries. The model is a valid effective field theory up to a high cutoff just a few orders of magnitude below the Planck scale. Furthermore, it can be UV completed in the context of Horava gravity. We discuss the observational predictions of the model. While the expansion history of the Universe turns out to be essentially indistinguishable from that of LCDM, the matter power spectrum is enhanced at subhorizon scales. The latter property can be used to discriminate the model from LCDM with current cosmological data.Speaker: Dr Sergey Sibiryakov (INR RAS)
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Higher-order coupled quintessenceWe study a coupled quintessence model in which the interaction with the dark matter sector is a function of the quintessence potential. Such a coupling can arise from a field dependent mass term for the dark matter field. The dynamical analysis of a standard quintessence potential coupled with the interaction explored here shows that the system possesses a late time accelerated attractor. In light of these results, we perform a fit to the most recent Supernovae Ia, Cosmic Microwave Background and Baryon Acoustic Oscillation data sets. Constraints arising from weak equivalence principle violation arguments are also discussed.Speaker: Dr Grigoris Panotopoulos (University of Valencia)
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Late cosmology constraints on thermal relic axions and axion-like particlesCosmological precision data can be used to set very strict constraints on Axions and Axion-like particles produced thermally in the big bang. We briefly review the known bounds and propose two new constraints for Axions and ALPs decaying in the early universe, based upon the concomitant dilution of baryon and neutrino densities, using WMAP7 and other cosmological data.Speaker: Mr Davide Cadamuro (Max-Planck-Institut für Physik)
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Pseudoscalar-photon mixing in an expanding UniverseWe establish the equation of motion of pseudoscalar particles coupled to an electromagnetic field in a classical gravitational background through the use of conformal time and flat geometry. We show that in general the expansion of the universe leads to larger mixing than in a stationary universe. We also show that for a broad range of parameters, one can obtain a resonance mixing, i.e. a region in which the mixing becomes maximum.Speaker: Dr Subhayan Mandal (University Of Liege)
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Supersonic Electroweak Baryogenesis: Baryon Asymmetry from Fast Bubble WallsIt is widely assumed that for the Electroweak Baryogenesis mechanism to be effective in generating the baryon asymmetry of the Universe, the first order phase transition bubbles have to expand at a subsonic speed (in order to allow for the diffusion of CP asymmetric currents in front of the wall). Here we present a new mechanism for Electroweak Baryogenesis that is effective for supersonic bubble walls, and relies on the formation of small bubbles of symmetric phase in the plasma behind the bubble wall (which is in the broken phase) due to the heating of the plasma as the wall passes by.Speaker: Mr Jose Miguel No (IPhT CEA Saclay)
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P6 – DM MODELS & LEPTOGENESIS VA4
VA4
IST Congress Centre
Convener: Michele Frigerio (IFAE, UAB, Barcelona)-
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Light Neutralino in the MSSMWe investigate the constraints to the light neutralino dark matter scenario in the minimal supersymmetric standard model from available experimental observations such as decays of B and K meson, relic dark matter abundance, and the search for neutralino and Higgs production at colliders. We find that two regions of the MSSM parameter space fulfill all the constraints: a fine-tuned strip with large tan beta where the lightest neutralino can be as light as 8 GeV, and a low tan beta region providing a neutralino mass larger than 16 GeV. The large tan beta strip, which can be compatible with recently reported signals from direct detection experiments, can be fully tested by means of low-energy observables and, in particular, by B_s -> mu mu and Higgs bosons searches at the LHC within the upcoming months.Speaker: Lorenzo Calibbi (MPP, Munich)
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Flavoured Co-annihilationsIn minimal supergravity (mSUGRA) or CMSSM, one of the main co-annihilating partners of the neutralino is the right handed stau, $\tilde{\tau}_R$. In the presence of flavor violation in the right handed sector, the co-annihilating partner would be a flavor mixed state. The flavor effect is two fold: (a) It changes the mass of the $\tilde{\tau}_{1}$, thus modifying the parameter space of the co-annihilation and (b) flavor violating scatterings could now contribute to the cross-sections in the early universe. In fact, it is shown that for large enough $\delta \sim 0.2$, these processes would constitute the dominant channels in co-annihilation regions. The amount of flavor mixing permissible is constrained by flavor violating $\tau \to \mu$ or $\tau \to e$ processes. For $\Delta_{RR}$ mass insertions, the constraints from flavor violation are not strong enough in some regions of the parameter space due to partial cancellations in the amplitudes. In mSUGRA, the regions with cancelations within LFV amplitudes do not overlap with the regions of co-annihilations. In NUHM, however, these regions do overlap leading to significant flavored co-annihilations. At the LHC and other colliders, these regions can constitute for interesting signals.Speaker: Prof. Sudhir Vempati (Indian Institute of Science, Bangalore)
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Non-Abelian Discrete Dark MatterWe consider the minimal model in which dark matter is stabilized by a non-Abelian discrete symmetry. The symmetry group is taken to be D3, which is the smallest non-Abelian finite group. The minimal model contains (nontrivial) singlet and doublet scalar representations of D3 which couple to the Standard Model fields via the Higgs portal. This construction predicts two species of dark matter over much of the parameter space. Nontrivial interactions under D3 lead to a novel thermal history of dark matter, while the multi-component nature of dark matter can be tested by future direct detection experiments.Speaker: Dr Adisorn Adulpravitchai (Max Planck Institute for Nuclear Physics)
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$A_4$-based neutrino masses with Majoron decaying dark matterWe propose an $A_4$ flavor-symmetric seesaw model where lepton number is broken spontaneously. A consistent two-zero texture pattern of neutrino masses and mixing emerges from the interplay of type-I and type-II seesaw contributions, with important phenomenological predictions. We show that, if the Majoron becomes massive, such seesaw scenario provides a viable candidate for decaying dark matter, consistent with cosmic microwave background lifetime constraints that follow from current WMAP observations. We also calculate the sub-leading one-loop-induced decay into photons which leads to a mono-energetic emission line that may be observed in future X-ray missions such as XeniaSpeaker: Dr Mariam Tórtola (IFIC, Valencia)
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Stability of the dark matter from non-abelian discrete flavor symmetryThere are several extension of the standard model predicting good dark matter candidates like in supersymmetry. However, it turns out that in most models the stability of the dark matter is assumed by hand, typically assuming a parity symmetry. Of course any of these models may be correct, but certainly it would be desirable to provide a fundamental explanation of the origin of the stability of the dark matter. The stabilization mechanism can give constraints on the structure of the model and therefore on the associated phenomenology. We propose a model where the stability is garantee by a residual Z2 symmetry arising from the spontaneous breaking of the flavor non-abelian discrete symmetry. We give two example based on A4 and D4.Speaker: Dr Stefano Morisi (IFIC/CSIC)
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The problem of initial conditions in flavoured leptogenesisWe discuss the conditions to realize a scenario of ‘strong thermal leptogenesis’, where the final asymmetry is fully independent of the initial conditions, taking into account both heavy and light neutrino flavor effects. In particular, the contribution to the final asymmetry from an initial pre-existing asymmetry has to be negligible. We show that in the case of a hierarchical right-handed (RH) neutrino mass spectrum, the only possible way is a N2 -dominated leptogenesis scenario with a lightest RH neutrino mass M1 << 10^9 GeV and with a next-to-lightest RH neutrino mass 10^12 GeV >> M2 >> 10^9 GeV. This scenario necessarily requires the presence of a heaviest third RH neutrino specie. Moreover, we show that the final asymmetry has to be dominantly produced in the tauon flavour while the electron and the muon asymmetries have to be efficiently washed out by the lightest RH neutrino inverse processes. Intriguingly, such seemingly special conditions for successful strong ther- mal leptogenesis are naturally fulfilled within SO(10)-inspired models. Besides the tauon N2 -dominated scenario, successful strong thermal leptogenesis is also achieved in scenarios with quasi-degenerate RH neutrino masses. We also comment on the supersymmetric case. We also derive an expression for the final asymmetry pro- duced from leptogenesis taking fully into account heavy neutrino flavour effects in the specific case M1 >> 10^12 GeV (heavy flavoured scenario), a result that can be extended to any other mass pattern.Speaker: Dr enrico bertuzzo (Scuola Normale Superiore)
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Quantum-Origin of the Matter-Antimatter AsymmetryThe standard models of particle physics and cosmology imply the absence of a sizable matter-antimatter asymmetry in the very early universe. Its existence, essential for the subsequent evolution of the universe, represents a major puzzle of present-day physics. Leptogenesis addresses this issue in an elegant way and can be realized in many standard model extensions. In this scenario a quantum interference in the lepton number violating decay of new heavy states leads to CP-violation. If the rapid expansion of the universe contributes a deviation from equilibrium this setting allows for the formation of an asymmetry. Remarkably, despite of the quantum-origin of this phenomenon, current computations are mostly still based on traditional Boltzmann equations. Newer calculations start from non-equilibrium quantum field theory since it allows to describe the quantum field theoretical interference and the different kinetic processes in the early universe in a consistent way. It accounts for finite density effects which have been shown to yield relevant corrections in the limit of hierarchical heavy neutrino masses. If these additional heavy states reside at the TeV scale leptogenesis is still viable provided that the self-energy contribution to the asymmetry is resonantly enhanced, i.e. if their masses are degenerate. In this case particular attention needs to be paid to the computation of the asymmetry as Boltzmann equations are in general not applicable.Speaker: Dr Andreas Hohenegger (Max-Planck-Institut für Kernphysik)
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10:30
Coffee Break IST Congress Center
IST Congress Center
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12:30
Lunch Break
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P7 - FLAVOUR AND MFV Main Auditorium
Main Auditorium
IST Congress Centre
Convener: Andreas Weiler-
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Flavour Physics in the Aligned Two-Higgs-Doublet ModelThe alignment in flavour space of the Yukawa matrices of a general two-Higgs-doublet model results in the absence of tree-level flavour-changing neutral currents. In addition to the usual fermion masses and mixings, the aligned Yukawa structure only contains three complex parameters, which are potential new sources of CP violation. For particular values of these three parameters all known specific implementations of the model based on discrete Z2 symmetries are recovered. One of the most distinctive features of the two-Higgs-doublet model is the presence of a charged scalar. In this talk, I will discuss its main phenomenological consequences in flavour-changing processes at low energies, ranging from leptonic to radiative decays and B-mixing, including recent results.Speaker: Martin Jung (IFIC)
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Yukawa Alignment in a Multi Higgs Doublet Model: An effective approachIn the two Higgs doublet model, natural flavour conservation can be achieved through the use of a discrete Z2 symmetry. A less restrictive condition is the requirement of alignment in the Yukawa sector. So far, alignment has been an anzatz, not rooted in a specific model. In this letter we present a model for alignment, which starts with 2+N Higgs doublets, with natural flavour conservation imposed by a discrete symmetry. Only two of these scalars couple to the fermions, the other N scalars are in a hidden sector. Assuming that the two scalar doublets coupled to fermions are heavy, their decoupling leads to an effective Yukawa interaction. The latter connects the fermions and the scalars of the hidden sector, and exhibits the same Yukawa coupling matrix for each of the N scalars.Speaker: Hugo Serodio (CFTP-IST)
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Minimal Flavour Violation with hierarchical squark massesIn a supersymmetric model with hierarchical squark masses we analyze a pattern of flavour symmetry breaking centered on the special role of the top Yukawa coupling and, by extension, of the full Yukawa couplings for the up-type quarks. For sufficiently heavy squarks of the first and second generation this leads to effective Minimal Flavour Violation of the Flavour Changing Neutral Current amplitudes. For this to happen we determine the bounds on the masses of the heavy squarks with QCD corrections taken into account, properly including previously neglected effects. We believe that the view presented in this paper altogether strengthens the case for hierarchical sfermions.Speaker: Marco Farina (Scuola Normale Superiore and INFN)
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CP Violation in Supersymmetry with Effective Minimal Flavour ViolationWe analyze CP violation in supersymmetry with Effective Minimal Flavour Violation, where the squarks of the first two generations are much heavier than the third generation ones. Unlike the case of standard Minimal Flavour Violation, we show that all the phases allowed by the flavour symmetry can be sizable without violating existing Electric Dipole Moment constraints, thus solving the SUSY CP problem. The EDMs at one and two loops are precisely analyzed as well as their correlations with the expected CP asymmetries in B physics.Speaker: Dr David Straub (Scuola Normale Superiore, Pisa)
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FCNC Effects in a Minimal Theory of Fermion MassesAs a minimal theory of fermion masses we extend the SM by heavy vectorlike fermions that mix with chiral fermions, such that small SM Yukawa couplings arise from small mixing angles. This model can be regarded as an effective description of the fermionic sector of a large class of existing flavor models and thus might serve as a useful reference frame for a further understanding of flavor hierarchies in the SM. Already such a minimal framework gives rise to FCNC effects through exchange of massive SM gauge bosons whose couplings to the light fermions get modified by the mixing. We derive general formulae for these corrections and discuss the bounds on the heavy fermion masses, finding that such fermions can still be as light as a TeV and therefore in the reach of the LHC. We discuss the connection of the minimal model to existing flavor models and consider additional structures that could be imposed in the heavy fermionic sector.Speaker: Dr Robert Ziegler (TUM/IAS Munich)
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Prospects on extensions of the Standard Model with vector-like quarksModifications of the Standard Model through the inclusion of vector-like quarks (i.e. quarks that are singlets under weak isospin transformations) potentially show signicant deviations in a vast number of predictions, ranging from intensively studied low energy flavour changing processes to high energy electroweak precision data and collider observables. In this talk we address the prospects for such models: (1) to be in agreement with Standard Model like available experimental information, (2) to explain deviations from Standard Model expectations in several observables (specially in the flavour sector), (3) to yield testable predictions for additional observables in the near future.Speaker: Dr Miguel Nebot (U. of Valencia - IFIC)
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B_s -> phi rho^0 and B_s -> phi pi^0 as a handle on isospin-violating New PhysicsThe 2.5 sigma discrepancy between theory and experiment observed in the difference A_CP(B^- --> pi^0 K^-)-A_CP(Bbar^0 --> pi^+ K^-) can be explained by a new electroweak penguin amplitude. We demonstrate that in presence of a such a new electroweak penguin amplitude the branching ratios of the purely isospin-violating decays B_s --> phi rho^0 and B_s --> phi pi^0 can be enhanced by up to an order of magnitude, without violating any constraints from other hadronic B decays. This makes them very interesting modes for LHCb and future B factories. We discuss both a model-independent analysis and a study within realistic New Physics models such as a modified-Z^0-penguin scenario, a model with an additional Z' boson and the Minimal Supersymmetric Standard Model (MSSM).Speaker: Dr Lars Hofer (Universität Würzburg)
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News on FCNC Processes through Horizontal Gauge BosonsNew neutral heavy gauge bosons appear automatically in many extensions of the Standard Model with an extended gauge sector. Typical examples are Z' and gauge-flavour models in which the flavour symmetry, necessary to explain the Standard Model fermion masses and mixings, or a part of it, is gauged. Often, additional heavy exotic fermions must also be introduced to cancel the anomalies from the new gauge sector. In phenomenologically testable scenarios, the lightest heavy bosons and fermions have masses around the TeV scale and may be directly produced in current colliders. On the other hand, indirect bounds are present since the neutral gauge bosons and exotic fermions affect the FCNC processes. In this talk, we discuss new aspects of phenomenology from such contributions, stressing in particular the role of QCD effects.Speaker: Emmanuel Stamou (TUM)
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P8 - LEPTONS (MOSTLY NEUTRINOS) VA3 (IST Congress Center)
VA3
IST Congress Center
Convener: Mariam Tórtola (IFIC, Valencia)-
75
New anomalies in the solar neutrino sector ?The solar neutrino sector shows two weak hints of anomalous behavior. First, the value of the mixing angle theta_12 inferred by the solar data is slightly different from that obtained by KamLAND. Second, as evidenced by the recent low-threshold measurements performed by Borexino, Super-Kamiokande and the Sudbury Neutrino Observatory, the solar 8B neutrino spectrum shows no sign of the low-energy upturn predicted by the standard MSW mechanism. These findings suggest the possibility that new subdominant dynamical effects may be at play in the matter-enhanced conversion of solar neutrinos. In fact, we show that both anomalies can be explained by new flavor-changing neutrino interactions with strength 0.1 G_F, whose presence is now favored at a non negligible statistical level.Speaker: Dr Antonio Palazzo (TUM)
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The reactor antineutrino anomaly and large extra dimensionsRecently, there has been a reevaluation of the reactor antineutrino spectra which increased the mean flux by 3%. The analysis of the former reactor antineutrino experiments with the new spectra revealed a 2.2 sigma deviation from the consolidated 3 neutrino framework. Together with gallium solar neutrino calibration experiments, this deviation is around 3 sigma. We show that in the context of a model with large extra dimensions the mixing between active neutrinos and sterile KK modes could be responsible for this anomaly.Speaker: Mr Pedro Machado (CEA-Saclay)
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Neutrinoless double beta decay in seesaw modelsWe study the general phenomenology of neutrinoless double beta decay in seesaw models. In particular, we focus on the dependence of the neutrinoless double beta decay rate on the mass of the extra states introduced to account for the Majorana masses of light neutrinos. For this purpose, we compute the nuclear matrix elements as functions of the mass of the mediating fermions and estimate the associated uncertainties. We then discuss what can be inferred on the seesaw model parameters in the different mass regimes and clarify how the contribution of the light neutrinos should always be taken into account when deriving bounds on the extra parameters. Conversely, the extra states can also have a significant impact, cancelling the Standard Model neutrino contribution for masses lighter than the nuclear scale and leading to vanishing neutrinoless double beta decay amplitudes even if neutrinos are Majorana particles. We also discuss how seesaw models could reconcile large rates of neutrinoless double beta decay with more stringent cosmological bounds on neutrino masses.Speaker: Dr Jacobo Lopez-Pavon (IPPP, Durham University)
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Present results of the ANTARES telescopeANTARES (Astronomy with a Neutrino Telescope and Abyss environmental RESearch) is the largest underwater neutrino detector currently operating in the Northern hemisphere. It consists of 885 PMTs, which are distributed in 12 vertical lines, various calibration systems and devices for environmental measurements. The telescope, installed at a depth of about 2500 meters in the Mediterranean Sea near Toulon (France), was completed in May of 2008. The PMTs detect the Cherenkov light emitted by high-energy neutrino induced muons. A likelihood-based algorithm is then used to reconstruct the muon tracks, allowing the knowledge of the neutrino direction. The main goal of the experiment is the search for high-energy neutrinos from the astrophysical sources where cosmic ray acceleration takes place. The design and status of the ANTARES detector will be presented. The latest results will be discussed, including searches for a diffuse high-energy cosmic neutrino flux, neutrinos from Gamma Ray Bursts, and for (galactic) point-like sources.Speaker: Dr Carla Distefano (LNS, Catania)
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Probing sterile neutrinos in meson decaysWe consider the nuMSM, which is the minimal standard model extended by three right handed neutrinos with masses lighter than the weak scale. In this model, the lightest right-handed neutrino $N_1$ is dark matter of the universe and the other two $N_2$ and $N_3$ are responsible to the neutrino masses in oscillation experiments and baryon asymmetry of the universe. In this talk, we would like to explain how to search $N_2$ and $N_3$ in decays of pions and kaons. Especially, we consider the case when their masses are lighter than the pion mass, and show the parameter range allowed from the various constraints by experiments and cosmology. We also present the implications to the future search experiments in pion and kaon decays.Speaker: Dr Takehiko Asaka (Niigata University)
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Lepton mixing under the lepton charge nonconservation, neutrino masses and oscillations and the "forbidden" decay \mu^-- --> e^-- + \gammaThe lepton-charge ( L_e, L_{\mu}, L_{\tau} ) non-conserving interaction leads to the mixing of the electron, muon and tau neutrinos, which manifests itself in spatial oscillations of a neutrino beam, and also to the mixing of the electron, negative muon and tau lepton – which, in particular, may be the cause of the "forbidden" radiative decay of the negative muon into the electron and \gamma quantum . Under the assumption that the nondiagonal elements of the mass matrices for neutrinos and ordinary leptons, connected with the lepton charge nonconservation, are the same, and by performing the joint analysis of the experimental data on neutrino oscillations and the experimental restriction for the probability of decay \mu^- --> e^- + \gamma per unit time, the following estimate for the lower bound of neutrino mass has been obtained : m^{(\nu)} > 1.5 eV/c^2 .Speaker: Dr Valery Lyuboshitz (Joint Institute for Nuclear Research ( Dubna ))
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Latest Result from the MEG ExperimentThe MEG Experiment searches for a lepton flavour violating muon decay, muon to electron and gamma, with a branching-ratio sensitivity of 10^{-13} in order to explore the parameter region predicted by many theoretical models beyond the Standard Model. The first physics result was published in 2009, and the consecutive physics run is currently running. The newest result of 2009/2010 data analysis and future prospects will be presented in addition to the experimental overview.Speaker: Dr Hajime Nishiguchi (KEK)
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P9 COMPOSITES AND EWSB VA4 (IST Congress Center)
VA4
IST Congress Center
Convener: Claudio Scrucca (Institut de Physique-Universite de Neuchatel-Unknown)-
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Leptons in Holographic Composite Higgs Models with Non-Abelian Discrete SymmetriesNon-Abelian Discrete Symmetries based on the group S4 are introduced in the lepton sector of Holographic Composite Higgs Models. The pattern of the neutrino mass mixing is naturally reproduced and the bounds on tree-level and radiative charged lepton decays are considerably alleviated. We explicitly show all these features in an explicit and very simple (with almost no free parameters!) 5D model in warped space.Speaker: Prof. Marco Serone (SISSA)
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The discrete composite HiggsWe analyze a discrete version of the 5-dimensional composite Higgs models obtained by dimensional deconstruction. We show that, if we use at least three deconstruction points, the Higgs potential as well as the S and T parameters are computable at 1-loop. We also study the properties of the simple set-up with only three deconstruction points, which describes two massive resonances of the KK towers and is already enough to reproduce the main phenomenological features of the composite Higgs scenario.Speaker: Dr Giuliano Panico (ETH Zurich)
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Composite unificationI will entertain the possibility of a TeV scale composite sector, that account at the same time for electroweak symmetry breaking and gauge coupling unification. In this scenario, the lightest new particles to be observed at the LHC are the composite partners of the Higgs and of the top quark, with a distinctive phenomenology.Speaker: Dr Michele Frigerio (IFAE & CNRS)
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86
Simple and Realistic Composite Higgs Models in Flat Extra DimensionsWe construct new composite Higgs/gauge-Higgs unification (GHU) models in flat space that overcome all the difficulties found in the past in attempting to construct models of this sort. The key ingredient is the introduction of large boundary kinetic terms for gauge (and fermion) fields. We focus our analysis on the electroweak symmetry breaking pattern and the electroweak precision tests and show how both are compatible with each other. Our models can be seen as effective TeV descriptions of analogue warped models. We point out that, as far as electroweak TeV scale physics is concerned, one can rely on simple and more flexible flat space models rather than considering their unavoidably more complicated warped space counterparts. The generic collider signatures of our models are essentially undistinguishable from those expected from composite Higgs/warped GHU models, namely a light Higgs, colored fermion resonances below the TeV scale and sizable deviations to the Higgs and top coupling.Speaker: Mr Mahmoud Safari (SISSA, Trieste)
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Radiative Symmetry Breaking of the Minimal Left-Right Symmetric ModelUnder the assumption of classical conformal invariance, we study the Coleman-Weinberg symmetry breaking mechanism in the minimal left-right symmetric model. This model is attractive as it provides a natural framework for small neutrino masses and the restoration of parity as a good symmetry of nature. We find that, in a large fraction of the parameter space, the parity symmetry is maximally broken by quantum corrections in the Coleman-Weinberg potential, which are a consequence of the conformal anomaly. As the left-right symmetry breaking scale is connected to the Planck scale through the logarithmic running of the dimensionless couplings of the scalar potential, a large separation of the two scales can be dynamically generated. The symmetry breaking dynamics of the model was studied using a renormalization group analysis. Electroweak symmetry breaking is triggered by the breakdown of left-right symmetry, and the left-right breaking scale is therefore expected in the few TeV range. The phenomenological implications of the symmetry breaking mechanism are discussed.Speaker: Martin Holthausen (Max Planck Institut für Kernphysik, Heidelberg)
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Discovering TechnicolorIn this talk, I will briefly review the mechanism of dynamical electroweak symmetry breaking. I will then show that a class of so called Walking Technicolor theories are able to pass the precision tests while producing a phenomenologically viable mass spectrum featuring a composite Higgs scalar. I will finally present collider signals of Walking Technicolor models for various processes, that can be observed during the present run of LHC, and their potential for discovering Technicolor.Speaker: Dr Stefano Di Chiara (CP3-Origins, Southern Denmark University)
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Analysis of the bounds on the parameters of Lorentz violationTypically, Lorentz-violating theories contain a large number of independent parameters. We analyze the bounds on these parameters and use them to quantify how precise Lorentz symmetry is today, according to experimental data. We evaluate a number of general formulas for Lorentz-violating field theories, and then apply them to the CPT-invariant, QED subsectors of the Standard Model Extension (SME), and the renormalizable high-energy Lorentz-violating Standard Model. We study the dependence of our results on the energy scale and other parameters, and address a number of applications.Speaker: Dario Buttazzo (Scuola Normale Superiore, Pisa)
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16:00
Coffee Break IST Congress Center
IST Congress Center
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P10 - SUSY, SEESAW & GUTS Main Auditorium (IST Congress Center)
Main Auditorium
IST Congress Center
Convener: Martin Hirsch (IFIC/CSIC)-
90
Fair scans of the seesaw. Consequences for predictions on LFV processesUsual analyses based on scans of the seesaw parameter-space can be biassed since they do not cover in a fair way the complete parameter-space. More precisely, we show that in the common 'R-parametrization', many acceptable R-matrices, compatible with the perturbativity of Yukawa couplings, are normally disregarded from the beginning, which produces biasses in the results. We give a straightforward procedure to scan the space of complex R-matrices in a complete way, giving a very simple rule to incorporate the perturbativity requirement as a condition for the entries of the R-matrix, something not considered before. As a relevant application of this, we show that the extended believe that BR(mu --> e, gamma) in supersymmetric seesaw models depends strongly on the value of theta_13 is an 'optical effect' produced by such biassed scans, and does not hold after a careful analytical and numerical study. When the complete scan is done, BR(mu --> e, gamma) gets very insensitive to theta_13. Moreover, the values of the branching ratio are typically larger than those quoted in the literature, due to the large number of acceptable points in the parameter-space which were not considered before. Including (unflavoured) leptogenesis does not introduce any further dependence on theta_13, although decreases the typical value of BR(mu --> e, gamma).Speaker: Mr Bryan Zaldívar (IFT UAM/CSIC)
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Supersymmetric mass spectra and the seesaw scaleThe talk is based on our recent paper arXiv:1101.2140. I will talk about supersymmetric mass spectra within two variants of the seesaw mechanism,commonly known as type-II and type-III seesaw. Using published, estimated errors on SUSY mass observables attainable at the LHC and in a combined LHC+ILC analysis, we calculate expected errors for the parameters of the models, most notably the seesaw scale. If SUSY particles are within the reach of the ILC, pure mSugra can be distinguished from mSugra plus type-II or type-III seesaw for nearly all relevant values of the seesaw scale. Even in the case when only the much less accurate LHC measurements are used, we find that indications for the seesaw can be found in favourable parts of the parameter space. Since our conclusions crucially depend on the reliability of the theoretically forecasted error bars, I will discuss in some detail the accuracies which need to be achieved for the most important LHC and ILC observables before an analysis, such as the one presented here, can find any hints for type-II or type-III seesaw in SUSY spectra.Speaker: Mr Laslo Reichert (Universidad de Valencia)
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Phenomenology of SUSY SU(5) with type I+III seesawIn a SUSY SU(5) model extended with an SU(5) adjoint, two neutrino masses can be generated through a mixed type I+III seesaw mechanism. I will discuss the phenomenology of this model, paying particular attention to flavour violating processes and dark matter relic density.Speaker: Carla Biggio (IFAE)
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Flavor Signals in SUSY GUTsSupersymmetric (SUSY) Grand Unified theories (GUTs) generally predict FCNC and CP violating processes to occur both in the leptonic and hadronic sectors. Assuming an underlying SU(5) group plus right-handed neutrinos (RN), we perform an extensive study of FCNC and CP violation, analyzing the correlations between leptonic and hadronic processes like mu-> e gamma and K-Kbar mixing, tau->mu gamma and b -> s transitions such as B_d -> phi K_s and Bs-Bsbar mixing. Moreover, we examine the impact of the considered scenario on the UT analyses, monitoring the low energy consequences implied by possible solutions to the various tensions in the present UT analyses.Speaker: Dr Minoru Nagai (TU Munich)
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Supersymmetric Left-Right models and low energy phenomenologyThe seesaw mechanism is the most popular explanation for the smallness of neutrino masses. However, its high scale makes impossible to test it directly and only indirect signals at low energies are reachable, lepton flavor violation in SUSY models being the best example. In this talk I will discuss lepton flavor violating signatures in the context of a SUSY left-right symmetric model that naturally incorporates the seesaw mechanism. In addition to the link between LFV and neutrino mixing angles, this non-minimal embedding of the seesaw leads to observable LFV effects in the right sleptons sector, contrary to minimal seesaw models where these are found to be totally negligible. Moreover, the deformation of the low energy spectrum leads to some other interesting differences. In particular, dark matter relic density might clearly depart from the standard picture.Speaker: Dr Avelino Vicente (Universität Würzburg)
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Interplay between neutrinos and higgs boson massesI would like to present the work done in collaboration with S. Heinemeyer, M.J.Herrero and S.Peñaranda(hep-ph/0084861; already accepted by JHEP). In this work we have done a full diagrammatic computation of the one-loop corrections from the neutrino/sneutrino sector to the lightest Higgs boson mass, M_h, within the context of the so-called MSSM-seesaw type I scenario, where three right handed neutrinos and their corresponding superpartners are included in order to explain light neutrino masses in a "natural" way. We have explored the dependence on all the parameters involved, with particular emphasis in the role played by the heavy Majorana scale and the physical neutrino mass. For simplicity, we have restricted ourselves to the case of one generation of neutrinos/sneutrinos. We have found sizable corrections to Mh, bigger than the expected accuracy in the measurement of mh in the LHC, for some regions of the MSSM-seesaw parameter space which were not expect that . I would also like to make few comments on our new results on the three generation case.Speaker: Mrs ANA MARIA RODRIGUEZ SANCHEZ (UAM)
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SUSY SO(10) with Yukawa unification and light sparticlesWe investigate supersymmetric SO(10) GUT model with $\mu<0$. The requirements of top-bottom-tau Yukawa unification, correct radiative electroweak symmetry breaking and agreement with the present experimental data may be met when the soft masses of scalars and gauginos are non-universal. We show how appropriate non-universalities can easily be obtained in the SO(10) GUT broken to the Standard Model. In many supersymmetric models it is quite difficult to have values of BR$(b\to s\gamma)$ and $(g-2)_\mu$ simultaneously in good agreement with the experimental data. We discuss how such agreement can be achieved in our model with $\mu<0$. In the region of the parameter space preferred by our analysis there are two main mechanisms leading to the LSP relic abundance consistent with the WMAP results. One is the coannihilation with the stau and the second is the resonant annihilation via exchange of the $Z$ boson or the light Higgs scalar. A very interesting feature of SO(10) models with negative $\mu$ is that they typically predict sparticle spectra much lighter than in models with positive $\mu$.Speaker: Marek Olechowski (University of Warsaw)
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Renormalizable SUSY SO(10) breakdown without large representations?We review the classical argument that, in order to break the high-scale SO(10) gauge symmetry down to the SU(3)xSU(2)xU(1) of the Standard Model at the renormalizable level in the SUSY context, higher tensors such as 210 are needed. We argue that, with extra vector-like matter multiplets at play, the freedom to flip SO(10) offers an option to implement the desired symmetry breaking descent in a very minimalistic regime, namely, with Higgs multiplets not bigger than the adjoint.Speaker: Michal Malinsky (IFIC/CSIC and University of Valencia)
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Unification without supersymmetry: where do we stand?It has been shown recently that the longstanding no-go excluding all the minimal nonsupersymmetric SO(10) unified scenarios where the first stage of the symmetry breaking is triggered by the 45-dimensional adjoint representation is confuted by the implementation of the one-loop effective potential. This observation reopens the possibility of a realistic and predictive unified model building whose final goal is the precise computation of the proton decay branching ratios.Speaker: Mr Luca Di Luzio (SISSA and INFN, Trieste)
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90
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P11 – DARK MATTER VA3
VA3
IST Congress Centre
Convener: Javier Redondo (MPP Munich)-
100
Spin-dependent WIMP-nucleus elastic scattering simplifiedToday a massive experimental effort is addressed towards the direct detection of weakly interacting massive particles (WIMP), that should form the dark matter halo of our galaxy, through elastic scattering with nuclei in underground detectors. We discuss a suitably normalized form of the isospin momentum dependent structure functions entering in the spin-dependent elastic neutralino-nucleus cross section. We compare these functions with the commonly used ones and discuss their advantages: in particular, these allow in the spin-dependent cross section to factorize the particle physics degrees of freedom from the momentum transfer dependent nuclear structure functions as it happens in the spin-independent cross section with the nuclear form factor. As an application we propose a scheme that allows to analytically determine the three elementary cross sections and connect the solutions to the relative sign between the proton and the neutron spin scattering amplitudes once the measurements of total event rate from three appropriate targets become available.Speaker: Dr Mirco Cannoni (Departamento de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21071 Huelva, Spain)
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Direct Detection of Electroweak-Interacting Dark Matter in the UniverseAssuming that the lightest neutral component in an SU(2)L gauge multiplet is the main ingredient of dark matter in the universe, we calculate the elastic scattering cross section of the dark matter with nucleon, which is an important quantity for the direct detection experiments. When the dark matter is a real scalar or a Majorana fermion which has only electroweak gauge interactions, the scattering with quarks and gluon are induced through one- and two-loop quantum processes, respectively, and both of them give rise to comparable contributions to the elastic scattering cross section. We evaluate all of the contributions at the leading order and find that there is an accidental cancellation among them. As a result, the spin-independent cross section is found to be O(10^−(46−48)) cm^2, which is far below the current experimental bounds.Speaker: Koji Ishiwata (Caltech)
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102
ElectroWeak Corrections to Dark Matter Indirect DetectionThe computation of the energy spectra of Standard Model particles originated from the annihilation/decay of dark matter particles is of primary importance in indirect searches of dark matter. In this talk we show how the inclusion of electroweak corrections significantly alter such spectra when the mass of dark matter particles is larger than the electroweak scale: soft electroweak gauge bosons are copiously radiated opening new channels in the final states which otherwise would be forbidden. All stable particles are therefore present in the final spectrum, independently of the primary channel of dark matter annihilation/decay. Such corrections are model independent.Speaker: Mr Filippo Sala (Scuola Normale Superiore, Pisa)
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Electroweak lights from Dark Matter annihilationRecent analyses have shown that the inclusion of electroweak corrections can alter significantly the energy spectra of Standard Model particles originated from dark matter annihilations. I will consider the important situation where the radiation of electroweak gauge bosons has a substantial influence: a Majorana dark matter particle annihilating into two light fermions. This process is in p-wave and hence suppressed by the small value of the relative velocity of the annihilating particles. The inclusion of electroweak radiation eludes this suppression and opens up a potentially sizeable s-wave contribution to the annihilation cross section. I will describe this effect in detail and discuss its impact on the fluxes of stable particles resulting from the dark matter annihilations, which are relevant for dark matter indirect searches. I will also comment on the effective field theory approach, pointing out that the opening of the s-wave is missed at the level of dimension-six operators and only encoded by higher orders.Speaker: Dr Andrea De Simone (EPFL)
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104
Conservative upper limits on WIMP annihilation cross section from Fermi extragalactic gamma raysThe spectrum of an isotropic extra-galactic gamma-ray background (EGB) has been measured by the Fermi-LAT telescope. The EGB is here derived by the subtraction of further contributions, with respect to the Fermi modelling, from undetected point sources and truly diffuse processes. Within the hypothesis that the residual EGB is entirely due to annihilation of galactic dark matter particles, we derive upper limits on the WIMP annihilation cross section. We work in a minimal modelling framework and consider our upper limits as strongly conservative. In addition, we set upper limits also in velocity suppressed annihilation cross section models as well as on the Sommerfeld enhancement of the WIMP cross section.Speaker: Ms Valentina De Romeri (IFIC Valencia)
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105
Accurate estimate of the relic density and the kinetic decoupling in non-thermal dark matter modelsNon-thermal dark matter generation is an appealing alternative to the standard paradigm of thermal WIMP dark matter. We reconsider non-thermal production mechanisms in a systematic way, and develop a numerical code for accurate computations of the dark matter relic density. We discuss in particular scenarios with long-lived massive states decaying into dark matter particles, appearing naturally in several beyond the standard model theories, such as supergravity and superstring frameworks. Since non-thermal production favors dark matter candidates with large pair annihilation rates, we analyze the possible connection with the anomalies detected in the lepton cosmic-ray flux by Pamela and Fermi. Concentrating on supersymmetric models, we consider the effect of these non-standard cosmologies in selecting a preferred mass scale for the lightest supersymmetric particle as dark matter candidate, and the consequent impact on the interpretation of new physics discovered or excluded at the LHC. Finally, we examine a rather predictive model, the G2-MSSM, investigating some of the standard assumptions usually implemented in the solution of the Boltzmann equation for the dark matter component, including coannihilations. We question the hypothesis that kinetic equilibrium holds along the whole phase of dark matter generation, and the validity of the factorization usually implemented to rewrite the system of coupled Boltzmann equations for each coannihilating species as a single equation for the sum of all the number densities which also allows to compute the kinetic decoupling temperature in case of coannihilating particles. This formalism can be applied also to other particle physics frameworks, and also to standard thermal relics within a standard cosmology.Speaker: Giorgio Arcadi (S.I.S.S.A.)
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Dark and visible matter with broken R-parity and the axion multipletA small breaking of R-parity reconciles thermal leptogenesis, gravitino dark matter and primordial nucleosynthesis. We find that the same breaking relaxes cosmological bounds on the axion multiplet. Naturally expected spectra become allowed and bounds from late particle decays become so weak that they are superseded by bounds from non-thermal axion production. In this sense, the strong CP problem serves as an additional motivation for broken R-paritySpeaker: Mr Jasper Hasenkamp (Hamburg U.)
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100
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P12 – COLLIDER PHENOMENOLOGY VA4
VA4
IST Congress Centre
Convener: Juan Antonio Aguilar Saavedra (LIP)-
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Weakly coupled resonant NP at the Tevatron ttbar forward-backward asymmetryWe show that Tevatron recent results on the $t \bar t$ forward-backward asymmetry for large invariant mass might be suggesting a possible contribution of a light ($\sim 700$ GeV) and narrow resonance in the $s$ channel. The resonant contribution of this particle to the $p \bar p \to t \bar t$ process would generate a high invariant-mass forward-backward asymmetry and, being narrow, the invariant mass spectrum would be only slightly modified close to the mass. We perform a phenomenological analysis and compare our results to the experimental ones, obtaining good agreement within the still large uncertainties on the later. We show that, due to small couplings to the light quarks, this resonance would be still beyond present sensitivity in searches for New Physics in dijet mass and angular distributions.Speaker: Ezequiel Alvarez (Universidad Nacional de San Luis, INFAP, Conicet, Argentina)
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Forward-Backward t tbar Asymmetry from Anomalous Stop Pair ProductionWe analyse a simple Standard Model (SM) extension with only two new light fields: a scalar partner of the top (stop) (with mass above m_t) and a light neutral fermion chi^0 (with mass of a few GeV), coupled to SM quarks via a Yukawa interaction. We show that such model can lead to a significant enhancement of the forward-backward asymmetry in t tbar production at the Tevatron via the additional t tbar pairs produced from (stop anti-stop) decays. The model satisfies existing constraints on new-physics searches both at low and high energies, and could even address the cosmological dark-matter abundance. The implications for future searches at the LHC are briefly outlined.Speaker: Dr Jernej Kamenik (Jozef Stefan Institute)
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Constrains on the Wtb vertex from early LHC dataThe recent measurements of top decay observables from ATLAS and the t-channel single top production cross section from CMS are used to set combined limits on the Wtb vertex structure. These limits are compared with the corresponding ones from Tevatron.Speaker: Nuno Castro (LIP)
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"Anomalous" Higgs Couplings at the LHCWe discuss the impact of non-standard Higgs couplings at the LHC. Using a model-independent -effective Lagrangian- approach, we focus on pure Higgs and Higgs-gauge operators, assuming that the new physics scale is larger than the electroweak one. Present constraints and future signals are explored, for those anomalous couplings which may be generated by tree-level exchange of unknown heavy particles. On a second stage, the quantum numbers of those possible tree-level mediators are identified, leading to additional correlated new signals.Speaker: Mr florian Bonnet (INFN Sezione di Padova)
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Precise predictions for Higgs production via gluon fusion in BSM scenariosThe search for the Higgs boson is a primary objective at the Tevatron and the LHC. The dominant production mechanism is gluon fusion, for which new physics effects can lead to significant deviations from the Standard Model predictions. We consider extensions of the Standard Model with heavy particles in various representations of the Lorentz group and with arbitrary couplings to the Higgs boson. We present the construction of an effective Lagrangian where the heavy particles are integrated out and the computation of the corresponding Wilson coefficient through three loops. We analyse the deviations of the Higgs production cross-section from the Standard Model predictions in scenarios as a four-generation Standard Model and composite Higgs models with an extended quark sector.Speaker: Dr Elisabetta Furlan (Brookhaven National Lab)
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Impact of extra particles on indirect Z' limitsWe study the possibility of relaxing the indirect limits on extra neutral vector bosons by their interplay with additional new particles. They can be systematically weakened, even below present direct bounds at colliders, by the addition of more vector bosons and/or scalars designed for this purpose. Otherwise, they appear to be robust.Speaker: Dr Jorge de Blas Mateo (University of Notre Dame)
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A weakly constrained W' at the early LHCWe discuss, within an effective approach, the phenomenology of a charged W' vector transforming as an iso-singlet under the Standard Model gauge group. Firstly, we present bounds from current data, finding that these are quite weak for suitable choices of the right-handed quark mixing matrix. Then, the resonant production at the early LHC of such a weakly constrained W' is discussed. We start by estimating the reach in the dijet final state, which is one of the channels where a W' signal would first appear, and then we analyse prospects for the more challenging discovery of W' decays into W gamma and WZ. We show in particular that the former can be used to gain insight on the possibly composite nature of the resonance.Speaker: Ennio Salvioni (CERN/University of Padua)
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Low scale Left Right symmetry and first LHC dataWe argue that a confirmation of a claim of observation of neutrinoless beta decay, in connection with constraints with cosmology, disfavours the standard mechanism due to Majorana neutrino mass. This implies a presence of new physics contribution near the TeV scale, which can relieve this tension and at the same time has a chance to be tested at the LHC. We discuss new contributions in the context of the minimal left-right symmetric model and show how they are related to the observables at the LHC. As a proof of concept, we demonstrate how the most recent data from the CMS in the two lepton and two jets channel puts a limit on the mass of the right-handed gauge boson. Despite a fairly low luminosity, we obtain a bound on W_R around 1.4 TeV in a large portion of parameter space where the right-handed neutrino mass is on the order of 100 GeV.Speaker: Dr Miha Nemevsek (ICTP)
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Soft gluon resummation for Drell-Yan and slepton-pair production in supersymmetryWe use a recent approach to threshold soft gluon resummation, based on effective field theory, to quantify the dynamical enhancement of the partonic threshold region for Drell-Yan and slepton pair production in supersymmetry. We evaluate the resummed invariant mass distribution and cross section at the NNLL order, and match the result onto NLO fixed-order calculation.Speaker: Dr Leonardo Vernazza (Johannes Gutenberg Universität)
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Coffee Break IST Congress Center
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Lunch Break
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Yukawa couplings and F-Theory Main Auditorium
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IST Congress Centre
Speaker: Luis Ibanez (Universidad Autonoma de Madrid) - 124
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18:00
Boat Trip
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Social Dinner at "Casa do Alentejo" Casa do Alentejo
Casa do Alentejo
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Coffee Break IST Congress Center
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Coffee Break IST Congress Center
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