Measurements of the T2K neutrino beam properties using the INGRID on-axis near detector
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 694 (2012) 211-223
Abstract:
Precise measurement of neutrino beam direction and intensity was achieved based on a new concept with modularized neutrino detectors. INGRID (Interactive Neutrino GRID) is an on-axis near detector for the T2K long baseline neutrino oscillation experiment. INGRID consists of 16 identical modules arranged in horizontal and vertical arrays around the beam center. The module has a sandwich structure of iron target plates and scintillator trackers. INGRID directly monitors the muon neutrino beam profile center and intensity using the number of observed neutrino events in each module. The neutrino beam direction is measured with accuracy better than 0.4 mrad from the measured profile center. The normalized event rate is measured with 4% precision. © 2012 Elsevier B.V. All rights reserved.Synchronization between remote sites for the MINOS experiment
44th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting 2012 (2012) 99-117
Abstract:
In the context of time-of-flight measurements, the timing at the departure and arrival locations is obviously critical to the outcome of the experiment. In the case of neutrino time-of-flight experiments, the locations are many hundreds of kilometers apart with synchronization requirements of nanoseconds for several months at a time. In addition to the already stringent set of requirements outlined above, the locations of the origin of the particle beam and the detector need to be precisely determined. NIST and USNO have provided the MINOS (Main Injector Neutrino Oscillation Search) collaboration with both hardware and expertise to synchronize the two sites of the experiment, the accelerator at Fermilab in Batavia, IL and the Soudan Mine in northern Minnesota. Two GPS receivers are installed at each location where the local clocks are commercial Cesium clocks. Two more GPS receivers are constantly traveling between locations (including NIST in Boulder, CO) to provide multiple differential calibrations of the fixed receivers. The availability of the TWTFST equipment from USNO allowed for one comparison between the GPS and TWSTFT for the link between the locations, providing an independent means of determining the accuracy of the synchronization. Several months of continuous GPS data are now available, including the two-way calibration instance and several differential GPS calibrations. The results of data processing yielded synchronization stability below one nanosecond with accuracy at the nanosecond level over several months. © (2012) by the Institute of Navigation. All rights reserved.Measurements of the T2K neutrino beam properties using the INGRID on-axis near detector
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment Elsevier 694 (2012) 211-223
Search for light scalar top-quark pair production in final states with two leptons with the ATLAS detector in √s =7 TeV proton–proton collisions
European Physical Journal C 72:11 (2012)
Abstract:
A search is presented for the pair production of light scalar top quarks in √s = 7 TeV proton–proton collisions recorded with the ATLAS detector at the Large Hadron Collider. This analysis uses the full data sample collected during 2011 running that corresponds to a total integrated luminosity of 4.7 fb−1. Light scalar top quarks are searched for in events with two opposite-sign leptons (e, μ), large missing transverse momentum and at least one jet in the final state. No excess over Standard Model expectations is found, and the results are interpreted under the assumption that the light scalar top decays to a b-quark in addition to an on-shell chargino whose decay occurs through a virtual W boson. If the chargino mass is 106 GeV, light scalar top-quark masses up to 130 GeV are excluded for neutralino masses below 70 GeV.Measurement of the b-hadron production cross section using decays to D *+μ -X final states in pp collisions at √s = 7 TeV with the ATLAS detector
Nuclear Physics B 864:3 (2012) 341-381