62151974
SuperB R&D computing program: HTTP direct access to distributed resources
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 1036cm−2s−1. The increasing network performance also in the Wide Area Network environment and the capability to read data remotely with good efficiency are providing new possibilities and opening new scenarios in the data access field. Subjects like data access and data availability in a distributed environment are key points in the definition of the computing model for an HEP experiment like SuperB. RD robust and reliable protocols as HTTP/WebDAV and xrootd are the subjects of a specific R&D line in a mid-term scenario. In this work we present the R&D results obtained in the study of new data access technologies for typical HEP use cases, focusing on specific protocols such as HTTP and WebDAV in Wide Area Network scenarios. Reports on efficiency, performance and reliability tests performed in a data analysis context have been described. Future R&D plan includes HTTP and xrootd protocols comparison tests, in terms of performance, efficiency, security and features available.
110146913
SuperB Simulation Production System
The SuperB asymmetric 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 peak luminosity of 1036 cm−2 s−1. The SuperB Computing group is working on developing a simulation production framework capable to satisfy the experiment needs. It provides access to distributed resources in order to support both the detector design definition and its performance evaluation studies. During last year the framework has evolved from the point of view of job workflow, Grid services interfaces and technologies adoption. A complete code refactoring and sub-component language porting now permits the framework to sustain distributed production involving resources from two continents and Grid Flavors. In this paper we will report a complete description of the production system status of the art, its evolution and its integration with Grid services; in particular, we will focus on the utilization of new Grid component features as in LB and WMS version 3. Results from the last official SuperB production cycle will be reported.
62691127
Computing for the next generation flavour factories
The next generation of Super Flavor Factories, like SuperB and SuperKEKB, present significant computing challenges. Extrapolating the BaBar and Belle experience to the SuperB nominal luminosity of 1036 cm−2s−1, we estimate that the data size collected after a few years of operation is 200 PB and the amount of CPU required to process them of the order of 2000 KHep-Spec06. Already in the current phase of detector design, the amount of simulated events needed for estimating the impact on very rare benchmark channels is huge and has required the development of new simulation tools and the deployment of a worldwide production distributed system. With the collider is in operation, very large data set have to be managed and new technologies with potential large impact on the computational models, like the many core CPUs, need to be effectively exploited. In addition SuperB, like the LHC experiments, will have to make use of distributed computing resources accessible via the Grid infrastructures while providing an efficient and reliable data access model to its final users. To explore the key issues, a dedicated R&D program has been launched and is now in progress. A description of the R&D goals and the status of ongoing activities is presented.
62980375
ATLAS detector simulation: status and outlook
The simulation program for the ATLAS experiment at CERN is currently in a full operational mode and integrated into the ATLAS's common analysis framework, ATHENA. The OO approach, based on GEANT4, and in use during the DC2 data challenge has been interfaced within ATHENA and to GEANT4 using the LCG dictionaries and Python scripting. The robustness of the application was proved during the DC2 data challenge. The Python interface has added the flexibility, modularity and interactivity that the simulation tool needs to tackle, in a common way, different full ATLAS simulations setups, test beams and cosmic ray studies. Generation, simulation and digitization steps were exercised for performance and robustness tests. The comparison with real data has been possible in the context of the ATLAS combined test beam (2004) and ongoing cosmic ray studies
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
110445306
The distributed production system of the SuperB project: description and results
The SuperB experiment needs large samples of MonteCarlo simulated events in order to finalize the detector design and to estimate the data analysis performances. The requirements are beyond the capabilities of a single computing farm, so a distributed production model capable of exploiting the existing HEP worldwide distributed computing infrastructure is needed. In this paper we describe the set of tools that have been developed to manage the production of the required simulated events. The production of events follows three main phases: distribution of input data files to the remote site Storage Elements (SE); job submission, via SuperB GANGA interface, to all available remote sites; output files transfer to CNAF repository. The job workflow includes procedures for consistency checking, monitoring, data handling and bookkeeping. A replication mechanism allows storing the job output on the local site SE. Results from 2010 official productions are reported.
55183423
Lopsided gauge mediation
It has been recently pointed out that the 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 μ-Bμ problem of gauge mediation. In fact, it allows for accommodating, with no further parameter tuning, large values of Bμ and of the other Higgs-sector soft masses, as predicted in models where both μ and Bμ 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. We discuss general parametric relations involving the fine-tuning of the model and various observables such as the chargino mass and the value of tan β. We build an explicit model and we study the constraints coming from LEP and Tevatron. We show that in spite of new interactions between the Higgs and the messenger superfields, the theory can remain perturbative up to very large scales, thus retaining gauge coupling unification.
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.
119125837
Cosmological perturbations from the Standard Model Higgs
We propose that the Standard Model (SM) Higgs is responsible for generating the cosmological perturbations of the universe by acting as an isocurvature mode during a de Sitter inflationary stage. In view of the recent ATLAS and CMS results for the Higgs mass, this can happen if the Hubble rate during inflation is in the range (1010−1014) GeV (depending on the SM parameters). Implications for the detection of primordial tensor perturbations through the B-mode of CMB polarization via the PLANCK satellite are discussed. For example, if the Higgs mass value is confirmed to be mh = 125.5 GeV and mt,αs are at their central values, our mechanism predicts tensor perturbations too small to be detected in the near future. On the other hand, if tensor perturbations will be detected by PLANCK through the B-mode of CMB, then there is a definite relation between the Higgs and top masses, making the mechanism predictive and falsifiable.
7068336
Low-scale gaugino mediation, lots of leptons at the LHC
Low-scale gaugino mediation predicts that gauginos are significantly heavier than scalar superpartners. In order of increasing mass the lightest superpartners are the gravitino, right-handed sleptons, and left-handed sleptons (no light neutralino). This implies that squark decay chains pass through one or more sleptons and typical final states from squark and gluino production at the LHC include multiple leptons. In addition, left-handed staus have large branching fractions into right-handed staus and the Higgs. As an example, we compute the spectrum of low-scale deconstructed gaugino mediation. In this model gauginos acquire masses at tree level at 5 TeV while scalar masses are generated radiatively from the gaugino masses.
32735806
On the effective operators for Dark Matter annihilations
We consider effective operators describing Dark Matter (DM) interactions with Standard Model fermions. In the non-relativistic limit of the DM field, the operators can be organized according to their mass dimension and their velocity behaviour, i.e. whether they describe s- or p-wave annihilations. The analysis is carried out for self-conjugate DM (real scalar or Majorana fermion). In this case, the helicity suppression at work in the annihilation into fermions is lifted by electroweak bremsstrahlung. We construct and study all dimension-8 operators encoding such an effect. These results are of interest in indirect DM searches.