NPL News Now

August 7, 2017
EXO-200 Phase-II Results Announced

The new neutrinoless double beta decay search results from EXO-200 was announced at the TAUP meeting after one year of Phase-II operation. In Phase-II, the detector energy resolution at the decay energy region is improved to 1.23%. External radon background between the cryostat and lead shield has been suppressed with radon free air. In addition, new analysis techniques for discriminating the gamma background has been implemented. Incorporating both hardware and software upgrades, the combined sensitivity for Phase-I and Phase-II data improved 2-fold to 3.7 x 10^25 years. No statistically significant signal was observed, leading to a lower limit on the 0vßß half-life of 1.8 x 10^25 yr at the 90% confidence level. The UIUC group led the front end electronics upgrade for Phase-II and contributed substantially to the analysis. Graduate student Shaolei Li studied the wire gain calibration and checked the grid correction for Phase-II. Graduate student Matthew Coon presented the new results at the 2017 Meeting of APD Division of Particle & Fields.

August 3, 2017
Young Scholars Program

A Poster Symposium concluded the inaugural Young Scholars program for high school students from underrepresented groups. The program, led by NPL, was sponsored by us together with the Department of Physics and the POETS Engineering Research Center of the Department of Mechanical Science and Engineering. About 60 people joined the 12 Young Scholars as they presented their work in a poster session held on Jul. 28 in the Loomis lobby. The projects ranged from biophysics, to high energy physics to nanomaterials. At the awards ceremony following the poster presentations, mentor Joseph Bryant, an undergrad in Prof. Perdekamp’s group was given the outstanding mentor award based on input from the students.

July 18, 2017
Semi-Annual nEDM Review

On Tue. Jul. 14 the neutron EDM experiment presented its responses to a request to revisit plans for the upcoming subsystem integration phase of the experiment. With some re-engineering, we were able to show an expected cost savings of about $4M in the roughly $25M remaining expenditures required to bring the experiment into operation. The technical changes involve a significant simplification in the mounting and shielding required for the helium-3 services system that is the Illinois responsibility. The review committee responded positively to the changes that they agreed both reduced costs and improved the experiment. The next review will be in December and will assess progress for the entire Critical Component Demonstration phase of the experiment that concludes this calendar year.

May 25, 2017
phYSics Young Scholars program to begin summer of 2017

The phYSics Young Scholars program will welcome 10 rising junior and senior high school students from the local area to examine, explore and consider exciting careers in scientific research. The 6 week summer program will give hands on experience to help students better fathom how we ask and answer questions in science. Young Scholars will be embedded in cutting-edge research laboratories at the Physics Department within the College of Engineering. They will be introduced to a variety of live experiments and scientific research as well as the ability to gain an understanding of science and its local and global impact. Young Scholars will have opportunities to build relationships with college students, professors, and other high school students. Visit the phYSics Young Scholars page for more information.

April 24, 2017
COMPASS publishes first hint of sign change in Drell-Yan Sivers function

The COMPASS collaboration at CERN submitted their 2015 measurement for publication in Physical Review Letters. The Sivers amplitude from the 2015 COMPASS spin-dependent Drell-Yan data provides the first hint of a sign change of the Sivers function measured in Drell-Yan (DY) as compared to measured in Semi-Inclusive Deep-Inelastic scattering (SIDIS). This sign change is a fundamental prediction of Quantum Chromo Dynamics, or QCD, the underlying theory of the strong interaction between quarks in the proton. The sign change is a milestone of the Nuclear Science Advisory Committee (NSAC). The Sivers function is one of the proton's Transverse-Momentum Dependent parton distributions (TMDs) and describes the correlation between the transverse spin of the parent proton and the transverse momentum of the probed quark. COMPASS has previously measured the Sivers amplitude in SIDIS and is therefore in the unique situation to conclude on the sign change without involving uncertainties related to TMD evolution.
The UIUC COMPASS group has significantly contributed to the success of the measurement in terms of instrumentation, coordination and data analysis. The Illinois authors are: Vincent Andrieux, Ihn-Jea Choi, Francesca Giordano, Robert Heitz, Jaakko Koivuniemi, Yakov Kulinich, Alain Magnon, Naomi Makins, Marco Meyer, Jen-Chieh Peng, Matthias Grosse Perdekamp, and Caroline Riedl. The arXiv version of the paper is available here:
A second COMPASS run of spin-dependent DY in 2018 will enhance the statistical significance of the measurement.

April 6, 2017
sPHENIX 2016 Test Beam Paper submitted

The sPHENIX combined calorimeter test beam paper from the 2016 Fermilab test has been submitted to the IEEE Transaction of Nuclear Science. The electromagnetic calorimeter was built half at the NPL and half at Tungsten Heavy Powder with finishing work done at the NPL. The Illinois group also led the analysis of the electromagnetic calorimeter performance. Facilities at the MRL were used by to characterize the properties of the tungsten powder used in the calorimeter. The Illinois contribution (over 20% of the authors) was the largest of any institution except for Brookhaven’s. The Illinois authors are: Virginia Bailey, John Blackburn, Michael Higdon, Simon Li, Vera Loggins, Mike Phipps, Anne Sickles, Peter Sobel, and Eric Thorsland. The tested calorimeters were found to meet the sPHENIX physics requirements. The paper is available here: