109930494
Interpretation of AMS-02 results: correlations among dark matter signals
The AMS-02 collaboration has recently released data on the positron fraction e+/(e−+e+) up to energies of about 350 GeV. If one insists on interpreting the observed excess as a dark matter signal, then we find it is best described by a TeV-scale dark matter annihilating into τ+τ−, although this situation is already severely constrained by gamma-ray measurements.The annihilation into μ+μ− is allowed by gamma-rays more than τ+τ−, but it gives a poorer fit to AMS-02 data. Moreover, since electroweak corrections induce correlations among the fluxes of stable particles from dark matter annihilations, the recent AMS-02 data imply a well-defined prediction for the correlated flux of antiprotons. Under the assumption that their future measurements will not show any antiproton excess above the background, the dark matter interpretation of the positron rise will possibly be ruled out by only making use of data from a single experiment. This work is the first of a program where we emphasize the role of correlations among dark matter signals.
18482364
Leptogenic Supersymmetry at the LHC
Leptogenic Supersymmetry is a scenario characterized by copious lepton production in cascade decays. Due to the high lepton multiplicity and the lack of significant missing energy, leptogenic supersymmetry provides very clean channels which can be probed already with the early LHC data. Furthermore, the Higgs may be discovered in the h→bb mode because the leptons accompanying Higgs production efficiently suppress the background.
18711359
Quantum Boltzmann equations in resonant leptogenesis
The quantum Boltzmann equations relevant for leptogenesis, obtained using non-equilibrium quantum field theory, are described. They manifest memory effects leading to a time-dependent CP asymmetry which depends upon the previous history of the system. This result is particularly relevant in resonant leptogenesis where the asymmetry is generated by the decays of nearly mass-degenerate right-handed neutrinos. The impact of the non-trivial time evolution of the CP asymmetry is discussed either in the generic resonant leptogenesis scenario or in the more specific Minimal Lepton Flavour Violation framework. Significant quantitative differences arise with respect to the usual approach in which the time dependence of the CP asymmetry is neglected.
118597692
Electroweak lights from Dark Matter annihilations
The energy spectra of Standard Model particles originated from Dark Matter annihilations can be significantly altered by the inclusion of electroweak gauge boson radiation from the final state. A situation where this effect is particularly important is when a Majorana Dark Matter particle annihilates 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 discuss the impact of this effect on the fluxes of stable particles resulting from the Dark Matter annihilations, which are relevant for Dark Matter indirect searches.
119185656
Conditional probabilities in the excursion set theory: generic barriers and non-Gaussian initial conditions
The excursion set theory, where density perturbations evolve stochastically with the smoothing scale, provides a method for computing the dark matter halo mass function. The computation of the mass function is mapped into the so-called first-passage time problem in the presence of a moving barrier. The excursion set theory is also a powerful formalism to study other properties of dark matter haloes such as halo bias, accretion rate, formation time, merging rate and the formation history of haloes. This is achieved by computing conditional probabilities with non-trivial initial conditions, and the conditional two-barrier first-crossing rate. In this paper we use the path integral formulation of the excursion set theory to calculate analytically these conditional probabilities in the presence of a generic moving barrier, including the one describing the ellipsoidal collapse, and for both Gaussian and non-Gaussian initial conditions. While most of our analysis associated with Gaussian initial conditions assumes Markovianity (top-hat in momentum space smoothing, rather than generic filters), the non-Markovianity of the random walks induced by non-Gaussianity is consistently accounted for. We compute, for a generic barrier, the first two scale-independent halo bias parameters, the conditional mass function and the halo formation time probability, including the effects of non-Gaussianities. We also provide the expression for the two-constant-barrier first-crossing rate when non-Markovian effects are induced by a top-hat filter function in real space.
118449412
Excursion set theory for generic moving barriers and non‐Gaussian initial conditions
Excursion set theory, where density perturbations evolve stochastically with the smoothing scale, provides a method for computing the mass function of cosmological structures like dark matter haloes, sheets and filaments. The computation of these mass functions is mapped into the so-called first-passage time problem in the presence of a moving barrier. In this paper we use the path-integral formulation of the excursion set theory developed recently to analytically solve the first-passage time problem in the presence of a generic moving barrier, in particular the barrier corresponding to ellipsoidal collapse. We perform the computation for both Gaussian and non-Gaussian initial conditions and for a window function which is a top-hat in wavenumber space. The expression of the halo mass function for the ellipsoidal collapse barrier and with non-Gaussianity is therefore obtained in a fully consistent way and it does not require the introduction of any form factor artificially derived from the Press–Schechter formalism based on the spherical collapse and usually adopted in the literature.
62187705
The calibration of the resistive plate chambers of ATLAS
Resistive Plate Chambers (RPC) are used in ATLAS to provide the first level muon trigger in the barrel region. The total size of the system is about 16000 m2 readout by about 350000 electronic channels. To reach the needed trigger performance, a precise knowledge of the detector working point (from the point of view of both high and low voltage settings) is necessary and the high number of readout channels calls for severe requirements on the analysis tools. First of all, high-statistics data samples will have to be used as input. Second, the results would me unmanageable without a proper interface to some database technology. Moreover, the CPU power needed for the analysis makes it necessary to use distributed computing resources. A set of analysis tools will be presented, coping with all the critical aspects of this task, ranging from the use of a dedicated data stream (the so-called muon calibration stream), to the automatic job submission on the GRID, to the implementation of an interface to the conditions database of ATLAS. The integration with Detector Control System information and the impact of the calibration on the performance of the reconstruction algorithms will be discussed as well.
110666241
Testing and evaluating storage technology to build a distributed Tier1 for SuperB in Italy
The SuperB asymmetric energy e+e−- collider and detector to be built at the newly founded Nicola Cabibbo Lab will provide a uniquely sensitive probe of New Physics in the flavor sector of the Standard Model. Studying minute effects in the heavy quark and heavy lepton sectors requires a data sample of 75 ab−-1 and a luminosity target of 1036 cm−-2 s−-1. This luminosity translate in the requirement of storing more than 50 PByte of additional data each year, making SuperB an interesting challenge to the data management infrastructure, both at site level as at Wide Area Network level. A new Tier1, distributed among 3 or 4 sites in the south of Italy, is planned as part of the SuperB computing infrastructure. Data storage is a relevant topic whose development affects the way to configure and setup storage infrastructure both in local computing cluster and in a distributed paradigm. In this work we report the test on the software for data distribution and data replica focusing on the experiences made with Hadoop and GlusterFS.
111077296
Exploiting new CPU architectures in the SuperB software framework
The SuperB asymmetric-energy e+e? collider and detector to be built at the newly founded Nicola Cabibbo Lab will provide a uniquely sensitive probe of New Physics in the flavour sector of the Standard Model. Studying minute effects in the heavy quark and heavy lepton sectors requires a data sample of 75ab?1 and a luminosity target of 1036cm?2s?1. These parameters require a substantial growth in computing requirements and performances. The SuperB collaboration is thus investigating the advantages of new CPU architectures (multi and many cores) and how to exploit their capability of task parallelization in the framework for simulation and analysis software. In this work we present the underlying architecture which we intend to use and some preliminary performance results of the first framework prototype.
119648296
FastSim: A Fast Simulation for the SuperB Detector
We have developed a parameterized (fast) simulation for detector optimization and physics reach studies of the proposed SuperB Flavor Factory in Italy. Detector components are modeled as thin sections of planes, cylinders, disks or cones. Particle-material interactions are modeled using simplified cross-sections and formulas. Active detectors are modeled using parameterized response functions. Geometry and response parameters are configured using xml files with a custom-designed schema. Reconstruction algorithms adapted from BaBar are used to build tracks and clusters. Multiple sources of background signals can be merged with primary signals. Pattern recognition errors are modeled statistically by randomly misassigning nearby tracking hits. Standard BaBar analysis tuples are used as an event output. Hadronic B meson pair events can be simulated at roughly 10Hz.
56414672
Computing at SuperB
Domenico Del Prete*, Fabrizio Bianchi, Vania Boccia, Vincenzo Ciaschini, Marco Corvo, Guglielmo De Nardo, Andrea Di Simone, Giacinto Donvito, Armando Fella, Paolo Franchini, Francesco Giacomini, Alberto Gianoli, Giuliano Laccetti, Stefano Longo, Steffen Luitz, Eleonora Luppi, Matteo Manzali, Leonardo Merola, Silvio Pardi, Alejandro Perez, Matteo Rama, Guido Russo, Bruno Santeramo, Roberto Stroili, Luca Tommasetti