A. Mengucci

INFN - Istituto Nazionale di Fisica Nucleare, Frascati, Latium, Italy

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Publications (22)16.5 Total impact

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    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 mixing angle $\theta_{13}$ in the standard mixing oscillation scenario encourages us to pursue the still missing results on leptonic CP violation and absolute neutrino masses. However, puzzling measurements exist that deserve an exhaustive evaluation. The NESSiE Collaboration has been setup to undertake conclusive experiments to clarify the muon-neutrino disappearance measurements at small $L/E$, which will be able to put severe constraints to models with more than the three-standard neutrinos, or even to robustly measure the presence of a new kind of neutrino oscillation for the first time. To this aim the use of the current FNAL-Booster neutrino beam for a Short-Baseline experiment has been carefully evaluated. Its recent proposal refers to the use of magnetic spectrometers at two different sites, Near and Far ones. Their positions have been extensively studied, together with the possible performances of two OPERA-like spectrometers. The proposal is constrained by availability of existing hardware and a time-schedule compatible with the undergoing project of a multi-site Liquid-Argon detectors at FNAL. The experiment to be possibly setup at Booster will allow to definitively clarify the current $\nu_{\mu}$ disappearance tension with $\nu_{e}$ appearance and disappearance at the eV mass scale.
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    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 mixing angle $\theta_{13}$ in the standard mixing oscillation scenario encourages us to pursue the still missing results on leptonic CP violation and absolute neutrino masses. However, puzzling measurements exist that deserve an exhaustive evaluation. The NESSiE Collaboration has been setup to undertake conclusive experiments to clarify the muon-neutrino disappearance measurements at small $L/E$, which will be able to put severe constraints to models with more than the three-standard neutrinos, or even to robustly measure the presence of a new kind of neutrino oscillation for the first time. To this aim the use of the current FNAL-Booster neutrino beam for a Short-Baseline experiment has been carefully evaluated. This proposal refers to the use of magnetic spectrometers at two different sites, Near and Far. Their positions have been extensively studied, together with the possible performances of two OPERA-like spectrometers. The proposal is constrained by availability of existing hardware and a time-schedule compatible with the CERN project for a new more performant neutrino beam, which will nicely extend the physics results achievable at the Booster. The possible FNAL experiment will allow to clarify the current $\nu_{\mu}$ disappearance tension with $\nu_e$ appearance and disappearance at the eV mass scale. Instead, a new CERN neutrino beam would allow a further span in the parameter space together with a refined control of systematics and, more relevant, the measurement of the antineutrino sector, by upgrading the spectrometer with detectors currently under R&D study.
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    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 theta13 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. The NESSiE Collaboration has been setup to undertake a definitive experiment to clarify the muon disappearance measurements at small L/E, which will be able to put severe constraints to any model with more than the three-standard neutrinos, or even to robustly measure the presence of a new kind of neutrino oscillation for the first time. Within the context of the current CERN project, aimed to revitalize the neutrino field in Europe, we will illustrate the achievements that can be obtained by a double muon-spectrometer system, with emphasis on the search for sterile neutrinos.
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    ABSTRACT: A new experiment with an intense ~2 GeV neutrino beam at CERN SPS is proposed in order to definitely clarify the possible existence of additional neutrino states, as pointed out by neutrino calibration source experiments, reactor and accelerator experiments and measure the corresponding oscillation parameters. The experiment is based on two identical LAr-TPCs complemented by magnetized spectrometers detecting electron and muon neutrino events at Far and Near positions, 1600 m and 300 m from the proton target, respectively. The ICARUS T600 detector, the largest LAr-TPC ever built with a size of about 600 ton of imaging mass, now running in the LNGS underground laboratory, will be moved at the CERN Far position. An additional 1/4 of the T600 detector (T150) will be constructed and located in the Near position. Two large area spectrometers will be placed downstream of the two LAr-TPC detectors to perform charge identification and muon momentum measurements from sub-GeV to several GeV energy range, greatly complementing the physics capabilities. This experiment will offer remarkable discovery potentialities, collecting a very large number of unbiased events both in the neutrino and antineutrino channels, largely adequate to definitely settle the origin of the observed neutrino-related anomalies.
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    ABSTRACT: This proposal describes an experimental search for sterile neutrinos beyond the Standard Model with a new CERN-SPS neutrino beam. The experiment is based on two identical LAr-TPC's followed by magnetized spectrometers, observing the electron and muon neutrino events at 1600 and 300 m from the proton target. This project will exploit the ICARUS T600, moved from LNGS to the CERN "Far" position. An additional 1/4 of the T600 detector will be constructed and located in the "Near" position. Two spectrometers will be placed downstream of the two LAr-TPC detectors to greatly complement the physics capabilities. Spectrometers will exploit a classical dipole magnetic field with iron slabs, and a new concept air-magnet, to perform charge identification and muon momentum measurements in a wide energy range over a large transverse area. In the two positions, the radial and energy spectra of the nu_e beam are practically identical. Comparing the two detectors, in absence of oscillations, all cross sections and experimental biases cancel out, and the two experimentally observed event distributions must be identical. Any difference of the event distributions at the locations of the two detectors might be attributed to the possible existence of {\nu}-oscillations, presumably due to additional neutrinos with a mixing angle sin^2(2theta_new) and a larger mass difference Delta_m^2_new. The superior quality of the LAr imaging TPC, in particular its unique electron-pi_zero discrimination allows full rejection of backgrounds and offers a lossless nu_e detection capability. The determination of the muon charge with the spectrometers allows the full separation of nu_mu from anti-nu_mu and therefore controlling systematics from muon mis-identification largely at high momenta.
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    ABSTRACT: Resistive Plate Chambers (RPCs) are widely used in high energy physics. While avalanche mode operation is mandatory in high rate environments (ATLAS and CMS experiments at LHC), streamer mode operation is often preferred in low rate applications because of the high signal amplitude. Typical mixtures for streamer operation are composed of Argon, Tetrafluoroethane and Isobutane, with additions of SF6 below 1% to reduce the charge delivered in the gas. In this paper, results about the streamer properties observed with different mixtures are presented.
    Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 06/2011; 640(1):76-84. DOI:10.1016/j.nima.2011.03.008 · 1.32 Impact Factor
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    ABSTRACT: OPERA is a dedicated experiment for the observation of v(mu) into v(tau) oscillations through tau appearance using a 730 km long baseline v(mu) beam from CERN to the Gran Sasso underground laboratory. The detector is equipped with two spectrometers for muon identification and charm background rejection. Bakelite RPCs are used as inner trackers inside the iron magnet of the spectrometers. The experiment has already performed two short runs in 2006 and 2007. Results about the RPC performances are presented.
    Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 05/2009; 602(3):635-638. DOI:10.1016/j.nima.2008.12.072 · 1.32 Impact Factor
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    ABSTRACT: The OPERA experiment is designed to study the νμ→ντ oscillation observing the ντ appearance in a pure νμ beam over a base line of 732 km from CERN to Gran Sasso Laboratory. The apparatus consists of a lead/emulsion-film target complemented by electronic detectors and muon spectrometers for muon charge and momentum measurements. The tracking inside the magnets is provide by Bakelite RPC chambers in a large scale application. The commissioning of the RPC system ended in August 2006. The paper present the layout of the RPC system and its performances.
    Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 05/2009; DOI:10.1016/j.nima.2008.12.071 · 1.32 Impact Factor
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    ABSTRACT: OPERA is an underground experiment to search for ντ appearance from a pure νμ beam produced at CERN. To flag the events due to the neutrino interactions with the rock surrounding the OPERA detector, a large VETO system, based on the use of Glass Resistive Plate Chambers (GRPCs) has been realized. We describe the VETO system, the GRPCs, the tests performed on the chambers before their installation. Presently, the VETO is in phase of commissioning. The first results of its underground operation are also presented.
    Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 05/2009; 602(3):653-657. DOI:10.1016/j.nima.2008.12.076 · 1.32 Impact Factor
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    ABSTRACT: OPERA is a long-baseline neutrino experiment at the Gran Sasso underground laboratories (LNGS), to observe appearance in a neutrino beam produced at CERN. The detector is a structure of two super modules, each built-up of a massive lead/nuclear-emulsion target complemented by electronic detectors and a magnetic spectrometer. The two magnets are instrumented by 1000 Resistive Plate Chambers (RPCs) detectors for a total surface of about 3200 . The slow control system has been designed to monitor and control all the critical parameters for the proper functioning of the spectrometers. The different hardware (Magnet and RPC High Voltage power supplies, RPC current meters, Magnet and RPC temperature sensors, RPC timing boards) is read out via CAN bus connections by several distributed clients. The clients write the data to a relational database (PostgresSQL) which is the heart of the system: it gives persistence to the data and allows to perform correlations useful to debug possible system malfunctioning. Among the various tools (histograms and XML Configuration Managers), a controller process checks for possible failures of the system using data from the database and generates warnings/alarms for people on shift.
    IEEE Transactions on Nuclear Science 03/2008; DOI:10.1109/TNS.2007.913470 · 1.46 Impact Factor
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    ABSTRACT: The OPERA neutrino experiment at the underground Gran Sasso Laboratory was designed to perform the first detection of neutrino oscillations in the appearance mode, through the study of νμ to νΤ oscillations and subsequent measurement of the tau decay products.
    IEEE Nuclear Science Symposium conference record. Nuclear Science Symposium 01/2008; DOI:10.1109/NSSMIC.2008.4774957
  • A. Mengucci · A. Paoloni · M. Spinetti · L. Votano
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    ABSTRACT: Gas mixtures have been studied in order to be used in the Resistive Plate Chambers (RPCs) of the OPERA spectrometers. We are interested in mixtures with a low R-134a concentration in order to reduce the streamer charge and the operating voltage without spoiling the usual RPC performances.
    Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 12/2007; 583(2-3-583):264-269. DOI:10.1016/j.nima.2007.09.030 · 1.32 Impact Factor
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    ABSTRACT: The design and construction of the 990-ton gapless iron magnets for the OPERA experiment represent a major challenge from the point of view of mechanics, electric and heat engineering. Two of such magnets have been built in a deep underground hall of the Gran Sasso laboratories between 2003 and 2006 and they have been switched on for the first time in March 2006. In this paper we discuss the construction and characterization of these devices. First experience with the CNGS beam are also reported.
    Nuclear Physics B - Proceedings Supplements 10/2007; DOI:10.1016/j.nuclphysbps.2007.08.017 · 0.88 Impact Factor
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    ABSTRACT: The construction and commissioning of the 990-ton gapless iron magnets for the OPERA experiment is presented. These magnets have been built in a deep underground hall of the Gran Sasso laboratories between 2003 and 2006 and they have been switched on for the first time in March 2006. In this poster we discuss the mechanic, electric and thermal characterization of these devices as well as measurements of the magnetic field by means of pickup coils. Moreover, we discuss the commissioning of the auxiliary systems (power supply, water cooling plant); first neutrino beam has been sent in August 2006 and is also reported.
    Nuclear Science Symposium Conference Record, 2006. IEEE; 12/2006
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    ABSTRACT: The OPERA experiment [1] will study νμ → ντ oscillations through τ appearance on the 732 Km long CERN to Gran Sasso baseline. The magnet yokes of the two muon spectrometers are instrumented with 44 layers of high resistivity bakelite Resistive Plate Chambers (RPCs) operated in streamer mode. Each layer covers about 70 m 2 . Four RPC planes were instrumented and the first tests were performed confirming a good behaviour of the installed RPCs in terms of intrinsic noise and operating currents. The measured noise maps agree with those obtained in the extensive quality tests performed at surface. Counting rates are below 20 Hz/m 2 . Single and multiple cosmic muon tracks were also reconstructed. The estimated efficiency is close to the geometrical limit and the very first measurements of the absolute and differential muon flux are in agreement with expectations.
    Nuclear Physics B - Proceedings Supplements 08/2006; 158. DOI:10.1016/j.nuclphysbps.2006.07.016 · 0.88 Impact Factor
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    ABSTRACT: OPERA is part of the CNGS project and it is an experiment dedicated to the observation of long-baseline nu<sub>mu</sub> into nu<sub>tau</sub> oscillations through tau appearance. Resistive Plate Chambers (RPCs) with bakelite electrodes are used to instrument the 2 cm gaps between the magnetized iron slabs of the two spectrometers. The RPC installation ended in may 2004 on the first spectrometer and in march 2005 on the second one. Before the installation, every RPC is subjected to a complete test chain in order to reject the poorer quality detectors. The tests are performed in dedicated facilities to ensure the proper RPC gluing, to measure its electrical properties and to verify the response to cosmic rays and the intrinsic noise levels. We have also tested the long term stability of real size OPERA RPC prototypes operated at cosmic ray fluxes for more than one year. On small size prototypes we are performing studies on the gas mixtures in order to reduce the total charge released in the gas for each detector count. The validation of the installed RPCs has been performed with pure nitrogen. A small part of them has been also tested with the gas mixture Ar/C<sub>2</sub>H<sub>2</sub>F<sub>4</sub>/i-C<sub>4</sub>H<sub>10 </sub>/SF<sub>6</sub>=75.4/20/4/0.6
    IEEE Transactions on Nuclear Science 01/2006; 52(6-52):2963 - 2970. DOI:10.1109/TNS.2005.862902 · 1.46 Impact Factor
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    ABSTRACT: OPERA is one of the two detectors foreseen in the CERN Neutrino to Gran Sasso project, devoted to the detection of νμ into ντ oscillations in the parameter region suggested by SuperKamiokande data on atmospheric neutrinos. Bakelite RPCs will be used to instrument the iron yoke of the muon spectrometers. We present the results of long-term (greater than 6 months) streamer operations of real size OPERA RPCs at cosmic rays fluxes. Given the very low rate observed in the underground Gran Sasso Laboratories, under 3 km w.e., even this short time period is equivalent to more than 10 OPERA years. Results of tests with different gas mixtures are reported, in view of decreasing the streamer charge of operation for the RPCs employed in the experiment.
    Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 11/2004; 533(1-2-533):42-45. DOI:10.1016/j.nima.2004.06.126 · 1.32 Impact Factor
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    ABSTRACT: The OPERA experiment foresees the use of about of RPCs, that will be tested before the installation in a dedicated cosmic ray test facility. The test facility is composed of 2 triggering walls selecting horizontal cosmic rays muons. Each wall houses 64 glass RPCs equipped with 128 horizontal Flat Cable Strips. The z-coordinate is measured with a standard digital chain, while the x-coordinate is obtained by measuring the propagation time of the signals along the strips. In this paper the performance of the trigger walls and the first results of the RPC debug are presented.
    Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 11/2004; 533(1-2-533):221-224. DOI:10.1016/j.nima.2004.07.031 · 1.32 Impact Factor
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    ABSTRACT: The final analysis of atmospheric neutrino events collected with the MACRO detector is presented. Three different classes of events, generated by neutrinos in different energy ranges, are studied looking at rates, angular distributions and estimated energies. The results are consistent for all the subsamples and indicate a flux deficit that depends on energy and path-length of neutrinos. The no-oscillation hypothesis is excluded at ∼ 5σ, while the hypothesis of vμ → vτ oscillation gives a satisfactory description of all data. The parameters with highest probability in a two flavor scenario are sin2 2θm = 1 and Δm2 = 0.0023 eV2. This result is independent of the absolute normalization of the atmospheric neutrino fluxes. The data can also be used to put experimental constrain on this normalization.
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    ABSTRACT: OPERA is part of CNGS project and it is an experiment dedicated to the observation of long-baseline v(mu) into v(T), oscillations through (T) appearance. Resistive Plate Chambers, RPCs, with bakelite electrodes are used for instrumenting the 2 cm gaps between the magnetized iron slabs of the two spectrometers. The RPCs installation in the first spectrometer ended in May 2004. Before the installation, every RPC is subject to a complete test chain for rejecting the worst quality detectors. The tests are performed in dedicated facilities for ensuring the proper RPC gluing, for measuring its electrical properties and for verifying the response to cosmic rays and the intrinsic noisiness. We have also tested the long term stability of real size OPERA RPC prototypes operated at cosmic ray fluxes for more than one year, which is equivalent, in terms of detectors countings, to about 20 OPERA years. On small size prototypes we are performing studies on the gas mixtures in order to reduce the total charge released in the gas for each detector count. The validation of the installed RPCs has been performed with pure nitrogen. A small part of them has been also tested with the gas mixture Ar/C2H2F4/i - C4H10/SF6 = 75.4/20/4/0.6.
    Nuclear Science Symposium/Medical Imaging Conference; 01/2004