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Open questions are still present in fundamental Physics and Cosmology, like the nature of Dark Matter, the matter-antimatter asymmetry and the validity of the particle

At the end of the 2011 run, the CERN CNGS neutrino beam has been briefly operated in lower intensity mode with similar to 10(12) p.o.t/pulse and with a proton beam structure made of four LHC-like extractions, each with a narrow width of similar to 3 ns, separated by 524 ns. This very tightly bunched beam allowed a very accurate time-of-flight measurement of neutrinos from CERN to LNGS on an event-by-event basis. The ICARUS T600 detector (CNGS2) has collected 7 beam-associated events, consistent with the CNGS collected neutrino flux of 2.2 x 10(16) p.o.t. and in agreement with the well-known characteristics of neutrino events in the LAr-TPC. The time of flight difference between the speed of light and the arriving neutrino LAr-TPC events has been analysed. The result delta t = 0.3 +/- 4.9(stat.) +/- 9.0(syst.) ns is compatible with the simultaneous arrival of all events with speed equal to that of light. This is in a striking difference with the reported result of OPERA (OPERA Collaboration, 2011) [1] claiming that high energy neutrinos from CERN arrive at LNGS similar to 60 ns earlier than expected from luminal speed. (C) 2012 Elsevier B.V. All rights reserved

We report an early result from the ICARUS experiment on the search for a ν µ → ν e signal due to the LSND anomaly. The search was performed with the ICARUS T600 detector located at the Gran Sasso Laboratory, receiving CNGS neutrinos from CERN at an average energy of about 20 GeV, after a flight path of ∼730 km. The LSND anomaly would manifest as an excess of ν e events, characterized by a fast energy oscillation averaging approximately to sin 2 (1.27∆m 2 new L/E ν ) ≈ 1/2 with probability P νµ→νe = 1/2 sin 2 (2θ new ). The present analysis is based on 1091 neutrino events, which are about 50% of the ICARUS data collected in 2010-2011. Two clear ν e events have been found, compared with the expectation of 3.7 ± 0.6 events from conventional sources. Within the range of our observations, this result is compatible with the absence of a LSND anomaly. At 90% and 99% confidence levels the limits of 3.4 and 7.3 events corresponding to oscillation probabilities P νµ→νe ≤ 5.4 × 10 −3 and P νµ→νe ≤ 1.1 × 10 −2 are set respectively. The result strongly limits the window of open options for the LSND anomaly to a narrow region around ∆m 2 , sin 2 (2θ) new = (0.5 eV 2 , 0.005), where there is an overall agreement (90% CL) between the present ICARUS limit, the published limits of KAR-MEN and the published positive signals of LSND and MiniBooNE Collaborations.

Liquid Argon Time Projection Chamber (LAr TPC) detectors offer charged particle imaging capability with remarkable spatial resolution. Precise event reconstruction procedures are critical in order to fully exploit the potential of this technology. In this paper we present a new, general approach to 3D reconstruction for the LAr TPC with a practical application to the track reconstruction. The efficiency of the method is evaluated on a sample of simulated tracks. We present also the application of the method to the analysis of stopping particle tracks collected during the ICARUS T600 detector operation with the CNGS neutrino beam.

We report an updated result from the ICARUS experiment on the search for ν µ → ν e anomalies with the CNGS beam, produced at CERN with an average energy of 20 GeV and travelling 730 km to the Gran Sasso Laboratory. The present analysis is based on a total sample of 1995 events of CNGS neutrino interactions, which corresponds to an almost doubled sample of the previously published result. Four clear ν e events have been visually identified over the full sample, compared with an expectation of 6.4 ± 0.9 events from conventional sources. The result is compatible with the absence of additional anomalous contributions. At 90% and 99% confidence levels, the limits to possible oscillated events are 3.7 and 8.3 respectively. The corresponding limit to oscillation probability becomes consequently 3.4 x 10 -3 and 7.6 x 10 -3 respectively. The present result confirms, with an improved sensitivity, the early result already published by the ICARUS Collaboration. .+g Neutrino interactions.

The ICARUS T600 detector, the largest liquid Argon Time Projection Chamber (LAr-TPC) realized after many years of R&D activities, was installed and successfully operated for 3 years at the INFN Gran Sasso underground Laboratory. One of the most important issues was the need of an extremely low residual electronegative impurity content in the liquid Argon, in order to transport the free electrons created by ionizing particles with very small attenuation along the drift path. The solutions adopted for the Argon recirculation and purification systems have permitted to reach impressive results in terms of Argon purity and a free electron lifetime exceeding 15 ms, corresponding to about 20 parts per trillion of O 2 -equivalent contamination, a milestone for any future project involving LAr-TPCs and the development of higher detector mass scales.-1 -arXiv:1409.5592v3 [physics.ins-det]

During May 2012, the CERN-CNGS neutrino beam has been operated for two weeks for a total of ∼ 1.8 × 10 17 p.o.t., with the proton beam made of bunches, few ns wide and separated by 100 ns. This beam structure allows a very accurate time of flight measurement of neutrinos from CERN to LNGS on an event-by-event basis.Both the ICARUS-T600 PMT-DAQ and the CERN-LNGS timing synchronization have been substantially improved for this campaign, taking advantage of additional independent GPS receivers, both at CERN and LNGS as well as of the deployment of the "White Rabbit" protocol both at CERN and LNGS.The ICARUS-T600 detector has collected 25 beam-associated events; the corresponding time of flight has been accurately evaluated, using all different time synchronization paths.The measured neutrino time of flight is compatible with the arrival of all events with speed equivalent to the one of light: the difference between the expected value based on the speed of light and the measured value is δt = tof c −tof ν = 0.10±0.67 stat. ±2.39 syst. ns. This result is in agreement with the value previously reported by the ICARUS Collaboration, δt = 0.3 ± 4.9 stat. ± 9.0 syst. ns, but with improved statistical and systematic accuracy.