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Search Results: 1 - 10 of 461905 matches for " A. Longhin "
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A new design for the CERN-Fréjus neutrino Super Beam
A. Longhin
Physics , 2011, DOI: 10.1140/epjc/s10052-011-1745-8
Abstract: We present an optimization of the hadron focusing system for a low-energy high-intensity conventional neutrino beam (Super-Beam) proposed on the basis of the HP-SPL at CERN with a beam power of 4 MW and an energy of 4.5 GeV. The far detector would be a 440 kton Water Cherenkov detector (MEMPHYS) located at a baseline of 130 km in the Fr\'ejus site. The neutrino fluxes simulation relies on a new GEANT4 based simulation coupled with an optimization algorithm based on the maximization of the sensitivity limit on the $\theta_{13}$ mixing angle. A new configuration adopting a multiple horn system with solid targets is proposed which improves the sensitivity to $\theta_{13}$ and the CP violating phase $\delta_{CP}$.
Optimization of neutrino beams for underground sites in Europe
A. Longhin
Physics , 2012,
Abstract: We present an optimization procedure for neutrino beams which could be produced at CERN and aimed to a set of seven possible underground sites in Europe with distances ranging from 130 km to 2300 km. Studies on the feasibility of a next generation very massive neutrino observatory have been performed for these sites in the context of the first phase of the LAGUNA design study. We consider specific scenarios for the proton driver (a high power proton driver at 4.5 GeV for the shortest baseline and a 50 GeV machine for longer baselines) and the far detector (a Water Cherenkov for the shortest baseline and a LAr TPC for longer baselines). The flux simulation profits of a full GEANT4 simulation. The optimization has been performed before the recent results on nu_e appearance by reactor and accelerator experiments and hence it is based on the maximization of the sensitivity on theta13. Nevertheless the optimized fluxes have been widely used since their publication on the internet (2010). This work is therefore mainly intended as a documentation of the adopted method and at the same time as an intermediate step towards future studies which will put the emphasis on the performances of beams for the study of delta_CP.
Large-angle scattering of multi-GeV muons on thin Lead targets
A. Longhin,A. Paoloni,F. Pupilli
Physics , 2015, DOI: 10.1109/TNS.2015.2473674
Abstract: The probability of large-angle scattering for multi-GeV muons in thin ($t/X_0 \sim 10^{-1}$) lead targets is studied. The new estimates presented here are based both on simulation programs (GEANT4 libraries) and theoretical calculations. In order to validate the results provided by simulation, a comparison is drawn with experimental data from the literature. This study is particularly relevant when applied to muons originating from $\nu_\mu^{CC}$ interactions of CNGS beam neutrinos. In that circumstance the process under study represents the main background for the $\nu_\mu \to \nu_\tau$ search in the $\tau \to \mu$ channel for the OPERA experiment at LNGS. Finally, we also investigate, in the CNGS context, possible contributions from the muon photo-nuclear process which might in principle also produce a large-angle muon scattering signature in the detector.
A novel technique for the measurement of the electron neutrino cross section
A. Longhin,L. Ludovici,F. Terranova
Physics , 2014, DOI: 10.1140/epjc/s10052-015-3378-9
Abstract: Absolute neutrino cross section measurements are presently limited by uncertainties on $\nu$ fluxes. In this paper, we propose a technique that is based on the reconstruction of large angle positrons in the decay tunnel to identify three-body semileptonic $K^+ \rightarrow e^+ \pi^0 \nu_e$ decays. This tagging facility operated in positron counting mode ("event count mode") can be employed to determine the absolute $\nu_e$ flux at the neutrino detector with ${\cal O}(1\%)$ precision. Facilities operated in "event by event tag mode" i.e. tagged neutrino beams that exploit the time coincidence of the positron at source and the $\nu_e$ interaction at the detector, are also discussed.
An Appraisal of Muon Neutrino Disappearance at Short Baseline
L. Stanco,S. Dusini,A. Longhin,A. Bertolin,M. Laveder
Advances in High Energy Physics , 2013, DOI: 10.1155/2013/948626
Abstract: Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long-standing problem of new physics beyond the Standard Model. The recent measurement of the third mixing angle in the standard mixing oscillation scenario encourages us to pursue the still missing results on leptonic CP violation and absolute neutrino masses. However, several puzzling measurements exist which deserve an exhaustive evaluation. We will illustrate the present status of the muon disappearance measurements at small and the current CERN project to revitalize the neutrino field in Europe with emphasis on the search for sterile neutrinos. We will then illustrate the achievements that a double muon spectrometer can make with regard to discovery of new neutrino states, using a newly developed analysis. 1. Introduction The unfolding of the physics of the neutrino is a long and exciting story spanning the last 80 years. Over this time the interchange of theoretical hypotheses and experimental facts has been one of the most fruitful demonstrations of the progress of knowledge in physics. The work of the last decade and a half finally brought a coherent picture within the Standard Model (SM) (or some small extensions of it), namely, the mixing of three neutrino flavour states with three , , and mass eigenstates. The last unknown mixing angle, , was recently measured [1–4], but still many questions remain unanswered to completely settle the scenario: the absolute masses, the Majorana/Dirac nature, and the existence and magnitude of leptonic CP violation. Answers to these questions will beautifully complete the (standard) three-neutrino model, but they will hardly provide an insight into new physics Beyond the Standard Model (BSM). Many relevant questions will stay open: the reason for neutrinos, the relation between the leptonic and hadronic sectors of the SM, the origin of Dark Matter, and overall where and how to look for BSM physics. Neutrinos may be an excellent source of BSM physics and their story is supporting that at length. There are actually several experimental hints for deviations from the “coherent” picture described above. Many unexpected results, not statistically significant on a single basis, appeared also in the last decade and a half, bringing attention to the hypothesis of sterile neutrinos [5]. A recent White Paper [6] contains a comprehensive review of these issues. In this paper we will focus on one of the most intriguing and long-standing unresolved result: the unexpected oscillation of neutrinos at relatively small
Charm and beauty production at HERA
Andrea Longhin
Physics , 2002,
Abstract: A selection of topics on open heavy quark production at HERA are reviewed here. Measurements of charm fragmentation parameters will be presented together with developments in the study of D* di-jet angular distributions. Charm production in deep inelastic scattering (DIS) is also discussed. Finally we deal with recent measurements of b cross sections using impact parameters in both DIS and photoproduction regimes.
CP violation and mass hierarchy at medium baselines in the large theta(13) era
S. Dusini,A. Longhin,M. Mezzetto,L. Patrizii,M. Sioli,G. Sirri,F. Terranova
Physics , 2012, DOI: 10.1140/epjc/s10052-013-2392-z
Abstract: The large value of theta(13) recently measured by rector and accelerator experiments opens unprecedented opportunities for precision oscillation physics. In this paper, we reconsider the physics reach of medium baseline superbeams. For theta(13) ~ 9 degree we show that facilities at medium baselines -- i.e. L ~ O(1000 km) -- remain optimal for the study of CP violation in the leptonic sector, although their ultimate precision strongly depends on experimental systematics. This is demonstrated in particular for facilities of practical interest in Europe: a CERN to Gran Sasso and CERN to Phyasalmi nu_mu beam based on the present SPS and on new high power 50 GeV proton driver. Due to the large value of theta(13), spectral information can be employed at medium baselines to resolve the sign ambiguity and determine the neutrino mass hierarchy. However, longer baselines, where matter effects dominate the nu_mu->nu_e transition, can achieve much stronger sensitivity to sign(Delta m^2) even at moderate exposures.
OPERA: waiting for the tau
Andrea Longhin,for the OPERA Collaboration
Physics , 2008,
Abstract: The OPERA experiment, whose aim is the direct observation of nu_mu ~> nu_tau oscillations in appearance mode in the CNGS high-energy neutrino beam, consists of a high-granularity modular target of nuclear emulsions-lead "bricks", richly instrumented with electronic detectors necessary for the location of neutrino interactions and kinematic analysis. After the first short runs of August 2006, October 2006 and October 2007, the experiment started early this summer its first long physics run (about 150 days). Operating at the final target mass of 1.35 kton, the 2008 run can realistically offer the first chance to observe a tau originated from a flavour oscillated nu_mu. This contribution will discuss the different aspects of the experiment, the challenges of the data handling and the recent achievements. It will also outline the various steps required for the analysis in nuclear emulsions from the "brick finding" to the vertex reconstruction.
Uma leitura hallidayiana das senten as clivadas do português
Sanderléia Roberta Longhin,Rodolfo Ilari
Alfa : Revista de Linguística , 2001,
Abstract: Neste trabalho, discutimos os critérios que, segundo Halliday (1966- 1967), explicam as estruturas "identificadoras" e "predicativas" que, juntas, d o conta do universo das cleft sentences do inglês. Mostramos que esses critérios parecem válidos para as cinco formas de senten as clivadas do português e, além disso, permitem levantar hipóteses para a compreens o dos processos que as originaram.
Aquisi o de tradi es discursivas: marcas de uma escrita heterogeneamente constituída
Sanderléia Roberta Longhin-Thomazi
Alfa : Revista de Linguística , 2011,
Abstract: Neste trabalho, partindo do pressuposto de que os esquemas de jun o de um texto, com suas possibilidades variáveis de realiza o quanto à arquitetura sintática e rela es semanticas, constituem um fen meno privilegiado para apreens o da Tradi o Discursiva em que o texto se insere (KABATEK, 2005), investigo em que medida a jun o contribui para elucidar o processo de aquisi o de Tradi es Discursivas na modalidade de enuncia o escrita. Para tanto, adoto um modelo de jun o de base funcionalista (HALLIDAY, 1985), fundado na n o discretude dos processos, e analiso uma amostra longitudinal de textos produzidos por duas crian as durante as quatro primeiras séries do Ensino Fundamental. Defendo que a aquisi o de tradi es da escrita se faz de forma constitutiva com as tradi es da oralidade e que essa constitui o heterogênea fica particularmente clara quando se atenta às decis es no domínio da jun o, em que a crian a faz escolhas sobre como juntar, no eixo sintagmático, e escolhas no conjunto dos juntores, no eixo paradigmático, deixando transparecer a natureza composicional das tradi es.
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