Abstract:

Recent measurements of the top quark charge asymmetry performed at both CDF and DZero produced tantalizing deviations from the SM prediction. Given that the dataset for these analyses will not improved dramatically, decisive confirmations will be required by the LHC experiments. After reviewing the measurements performed at the Tevatron, I will discuss the challenges to perform these measurements at the LHC. In particular I will describe how one needs to exploit the large datasets of top quarks at the LHC to compensate for the difficulty to perform such a measurement in a symmetric proton-proton collider environment.

Abstract:

Many BSM theories predict new heavy particle states that are identical to their SM counterparts but are heavier. In SUSY, thesuperpartners differ in spin by a half-integer from their SM counterparts, whereas Kaluza-Klein resonances have the same spin as the SM zero modes. Measuring spin thus provides a crucial handle on distinguishing new physics models at the LHC. The first part of this talk is about spin measurement of new particles at the LHC using the azimuthal angular distribution of decay products from a parent particle whose spin we wish to measure. This technique is model independent and relies only on simple angular momentum rules and quantum mechanics. In the second part of the talk I will discuss WZ scattering at the LHC. We find that the same azimuthal angle can be used as a probe of a strongly coupled Higgs sector.

Abstract:

First, I will briefly introduce some aspects of supersymmetry breaking and its mediation to the MSSM. I will then consider a scenario with two susy breaking hidden sectors which decouple when their respective couplings to the visible particles are switched off. In such a scenario one expects to find two light fermions: the goldstino and the pseudo-goldstino. I will discuss the mass induced to the pseudo-goldstino by radiative corrections in a general gauge mediation framework, showing that this mass is naturally around the GeV scale. I will finally discuss some of the phenomenological consequences and possible collider signatures.

Abstract:

TBAWe study instanton partition function of 4d N=2 SCFT arising from the 6d (2, 0)-theory compactified on a Riemann surface. There are different realizations of the same gauge theory coming from the accidental isomorphisms of the low-rank Lie algebras. We find such different realizations of the same gauge theory give the same instanton partition function only after a non-trivial mapping of the UV gauge couplings. The map can be understood as a cover/base map of the corresponding Riemann surface. Using this relation, we extend the 4d/2d Alday-Gaiotto-Tachikawa correspondence to D-type quivers and also to non-linear A_1 Sicilian quiver theories.

Abstract:

The last year has seen tremendous progress on the Higgs boson search at LHC. This talk will review the methods we use to search for the Higgs boson at ATLAS, the results from this year's data, and the prospects for Higgs discovery in the next few years.

Abstract:

The "Narrow-Width Approximation" is a convenient tool for the factorization of a longer decay chain into production and subsequent decay of a particle with a small width compared to its mass. However, this approximation cannot be applied in the case of sizable interference between propagator contributions of different particles that are close to their mass shell. The spectrum of the MSSM may contain particles with a mass difference of the order of their decay widths. In order to deal with such a situation, a generalization of the usual Narrow-Width Approximation is analyzed which allows for a consistent treatment of interference effects between such nearly mass-degenerate particles. The phenomenological consequences will be discussed for the example process of Higgs boson production and subsequent decay from the decay of a heavy neutralino.

Abstract:

The observations of the first traces of cosmic structure in the Cosmic Microwave Background are in excellent agreement with the predictions of Inflation. However as we shall see, the standard inflationary account, is not fully satisfactory as it can not explain the transition from an homogeneous and isotropic early stage to a latter one lacking those symmetries. The problem can be seen to be related to the exacerbated manner in which the interpretational problems of quantum theory appear in the cosmological setting, and in particular to the inadequacies of the decoherence approach to the task at hand. We will argue, therefore, that an extra ingredient, corresponding to novel physics, is needed to complete the usual account for the emergence of the seeds of structure, and that, as suggested by R. Penrose and L. Diosi, quantum gravity might be the place from where this new physics ultimately emerges. We will show that generically such new ingredient affects in very specific ways the observational predictions and we will argue that very high precision observations, can be used to constrain various aspects of phenomenological proposals made in this regard.

Abstract:

In anomaly-mediated supersymmetry breaking, superpartners in a hidden sector have masses that are proportional to couplings squared, and so naturally freeze out with the desired dark matter relic density for a large range of masses. We present an extremely simple realization of this possibility, with WIMPless dark matter arising from a hidden sector that is supersymmetric QED with SU(N_F). Dark matter is multi-component, composed of hidden leptons and sleptons with masses anywhere from 10 GeV to 10 TeV, and hidden photons provide the thermal bath. The dark matter self-interacts through hidden sector Coulomb scatterings that are potentially observable. In addition, the hidden photon contribution to the number of relativistic degrees of freedom is in the range \Delta N_eff ~ 0 - 2, and, if the hidden and visible sectors were initially in thermal contact, the model predicts \Delta N_eff ~ 0.2 - 0.4. Data already taken by Planck may provide evidence of such deviations.

Abstract:

I will discuss recent work reconsidering the derivation of anomaly mediated supersymmetry breaking. I will present a general formalism where the F-term of the conformal compensator superfield is arbitrary. This allows for a continuous interpolation between the original derivation and a more recent Dine-Seiberg derivation of anomaly mediation. This derivation shows explicitly that the physical soft parameters are independent of the compensator F-term and results of two formalisms agree. Finally, I will discuss the role of supersymmetric and non-supersymmetric thresholds in the effective low energy Lagrangian as well as the effects of explicit small mass parameters (such as μ-term) on the superpartner spectrum.

Abstract:

Spike sorting is a well documented problem which involves discrimination between the activity of different neurons and background electrical noise based on analysis of the shape of the waveforms collected on one or more electrodes in neural tissue. Classical spike sorting techniques apply dimensionality reduction algorithms such as PCA to the recorded waveforms, before running clustering algorithms such as K-Means or Expectation Maximization on the resulting data in order to separate spikes coming from different neurons. With these methods, correct identification of the number of neurons found on an electrode is challenging. Performance also strongly degrades when the neuron waveforms change over time, for example in the case of bursting neurons. In this talk, we present a novel spike-sorting algorithm based on the clustering method known as "Spectral Clustering". We show how to apply this technique on very large datasets (hundreds of thousands of action potentials) with non-trivial cluster shapes. Our algorithm provides a simple quantitative criterion for determining the number of neurons found on an electrode. Performance of this novel algorithm was compared with that of a well established automated clustering method and of manual clustering of three large-scale recordings of rat retinal activity. The novel algorithm was shown to perform as well as manual clustering and significantly outperformed the previous automated method.

Abstract:

3D radiation sensors consist of a three-dimensional array of vertical columnar electrodes of both doping types, etched perpendicularly to the wafer surface and penetrating through the entire substrate. In planar detectors the depletion voltage and the collected charge depend on the substrate thickness; on the contrary, in 3D sensors these features depend on the detector layout, i.e., on the distance between the columnar electrodes, which can be short enough to yield full depletion and high electric fields at low bias voltage, thus allowing for short collection times and high radiation hardness. One important evolution of the 3D concept, the so-called "active edge" should also be mentioned. This technique makes use of deep ohmic trenches to terminate the detectors, thus eliminating the need of the cutting procedure and reducing the insensitive edge region to less than 10 μm, to be compared to few hundreds μm for standard planar detectors. This option enables building large area seamlessly tiled detector matrices, i.e., without sensor overlap within the same layer, and thus greatly facilitates the layout, reduces the material budget, and improves the momentum resolution. Besides full-3D detectors with active edges pioneered by S. Parker and collaborators in the late 90's and fabricated at the Stanford Nanofabrication Facility, other modified 3D detectors have been proposed in the past few years, among them 3D-STC (Single Type Column) and 3D-DDTC (Double-side Double Type Column) detectors, aiming at a simplification of the manufacturing technology in view of volume productions. In particular, the 3D-DDTC approach (in two slightly different versions) is being pursued CNM-IMB (Barcelona, Spain) and by FBK (Trento, Italy). 3D sensors are currently emerging as one of the most promising technologies for innermost layers of tracking at the foreseen upgrades of the Large Hadron Collider. In particular, in the past few years, important progress has been made in 3D sensors due to the anticipated installation schedule of the ATLAS Insertable B Layer during the first long shut down of the LHC in 2013-2014. Within the ATLAS 3D Sensor Collaboration, the double-sided 3D technologies from FBK and CNM have been chosen for the IBL Sensor Qualification, with very good results both in terms of tracking performance, radiation hardness and fabrication yield. This talk will review the recent developments of 3D and active edge sensors in Trento, including design and technological aspects as well as selected results from the electrical and functional characterization.

Abstract:

The screening of external electric and magnetic fields in plasma with electrically charged Bose condensate is considered. The plasma is supposed to be electrically neutral, the charge of the condensate being compensated by other particles. It is shown that the screening behavior of electrically charged impurities is drastically different from the usual Debye law. In particular, the screening becomes power law and oscillating with distance. The latter is similar to Friedel oscillations in plasma with strongly degenerate fermions but physics is different. Similar behavior is found for penetration of magnetic field into plasma, which very much differs from the usual Meissner exponential damping. The results may have applications for high temperature superconductors in BEC phase and for generation of large scale magnetic fields in the early universe. The latter could be seeds of the observed galactic and intergalactic magnetic fields.