D. Cline

Precision measurement of the neutrino velocity with the ICARUS detector in the CNGS beam

A bstractDuring May 2012, the CERN-CNGS neutrino beam has been operated for two weeks for a total of ~1.8u2009×u20091017 p.o.t., with the proton beam made of bunches, few ns wide and separated by 100xa0ns. 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 = tofc−tofνu2009=u20090.10u2009±u20090.67stat.u2009±u20092.39syst.u2009ns. This result is in agreement with the value previously reported by the ICARUS Collaboration, δtu2009=u20090.3u2009±u20094.9stat.u2009±u20099.0syst.u2009ns, but with improved statistical and systematic accuracy.

Measurement of through-going particle momentum by means of multiple scattering with the ICARUS T600 TPC

The ICARUS collaboration has demonstrated, following the operation of a 600xa0ton (T600) detector at shallow depth, that the technique based on liquid argon time projection chambers is now mature. The study of rare events, not contemplated in the standard model, can greatly benefit from the use of this kind of detectors. In particular, a deeper understanding of atmospheric neutrino properties will be obtained thanks to the unprecedented quality of the data ICARUS provides. However if we concentrate on the T600 performance, most of the νμ charged current sample will be partially contained, due to the reduced dimensions of the detector. In this article, we address the problem of how well we can determine the kinematics of events having partially contained tracks. The analysis of a large sample of atmospheric muons collected during the T600 test run demonstrates that, in case the recorded track is at least one meter long, the muon momentum can be reconstructed by an algorithm that measures the multiple Coulomb scattering along the particle’s path. Moreover, we show that momentum resolution can be improved by almost a factor two using an algorithm based on the Kalman filtering technique.

Direct Search for Dark Matter Particles with Very Large Detectors

We briefly discuss the expected level of supersymmetric dark matter crosssections as a reference for dark matter detectors. We then discuss the current ZEPLIN II program as a prototype of large liquid Xenon detectors. Cryoarray is a possible cryogenic detector. Finally we discuss ZEPLIN IV and other one ton liquid Xenon detectors and the limiting backgrounds for such detectors.

ZEPLIN IV: A One Ton WIMP Detector

We describe the research and development program carried out by the UCLA — Torino group leading to the ZEPLIN II detector under construction for the Boulby Laboratory. Knowledge of ZEPLIN II performance will help in the design and construction of ZEPLIN IV. This detector could be located at a U.S. underground laboratory (WIPP site or others) or elsewhere. We show that a detector of this size is required to observe SUSY WIMPS.

ZEPLIN II and Amplification of Primary Scintillation

We will discuss the detailed design of the 30 kg two-phase xenon ZEPLIN II detector, to be installed in the Boulby mine, UK in early 2001, for the direct detection of WIMP dark matter. Xenon provides many advantages for WIMP searching. Also we will describe a possible primary amplification method with Csl internal photo cathode. We achieved more than 10 times amplification ratio for a initial photon. This method will maximize the efficiency of ZEPLIN II to search for Super-Symmetric Dark Matter.

Experimental and theoretical high energy physics research. [UCLA]

This is the final report of the UCLA High Energy Physics DOE Grant No. DE-FG02- 91ER40662. This report covers the last grant project period, namely the three years beginning January 15, 2010, plus extensions through April 30, 2013. The report describes the broad range of our experimental research spanning direct dark matter detection searches using both liquid xenon (XENON) and liquid argon (DARKSIDE); present (ICARUS) and RD ultra-high-energy neutrino and cosmic ray detection (ANITA); and the highest-energy accelerator-based physics with the CMS experiment and CERN’s Large Hadron Collider. For our theory group, the report describes frontier activities including particle astrophysics and cosmology; neutrino physics; LHC interaction cross section calculations now feasible due to breakthroughs in theoretical techniques; and advances in the formal theory of supergravity.

Study of the Galactic Center with a High Resolution Gamma Ray Telescope

It is generally accepted that massive black holes are the most likely source for the energy radiated from active galactic nuclei, and may explain the enormous amount of energy emitted by quasars, radio galaxies, Seyfert galaxies, and BL Lacertid objects(1). Although the detailed mechanisms of the black hole formation in galactic nuclei are not clear at present, it seems to be quite possible that the formation of massive black holes is a general outcome of the evolution of galactic nuclei(2).