DEPARTMENT OF PHYSICS AND ASTRONOMY

In 2012 Physics World chose the discovery of a "Higgs-like Boson" by the ATLAS and CMS teams at CERN as their Top Breakthrough of the Year.  Physics World described the discovery as "the most important physics breakthrough so far in the 21st century." Congratulations to Northwestern Profs.Mayda Velasco, Michael Schmitt, and Kristian Hahn for their contributions to this amazing discovery!

The Higgs discovery has been making year-end lists around the world. Prof. Mayda Velasco's work was also featured in the Puerto Rican newspaper El Nuevo Dia's list of the top 5 scientific discoveries of 2012.

Prof. Heidi Schellman has been appointed as U.S.representative on the H Commission of Particles and Fields (C11) of IUPAP, the International Union of Pure and Applied Physics.

The mandate of C11 is "To promote the exchange of information and views among the members of the international scientific community in the general field of Particles and Fields".

The AAAS is an international non-profit organization whose mission is to "advance science, engineering, and innovation throughout the world for the benefit of all people."

See the full list of 2012 fellows here.

Prof. Jim Sauls has just been awarded the 2012 John Bardeen Prize recognizing his contributions to the theory of unconventional superconductivity, most importantly manifest in the heavy fermion superconductor UPt3, high-temperature cuprate superconductors, and superfluid 3He. The prize will be formally presented to him and two others, Chandra Varma and Steve Kivelson, at the M2S superconductivity meeting this August.

The John Bardeen Prize is awarded for theoretical work that has provided significant insights on the nature of superconductivity and has led to verifiable predictions.

When tensioned, ordinary materials expand along the direction of the applied force. But a new paper published this week by Zachary G. Nicolaou and Prof. Adison E. Motter  demonstrates that not all materials have to be that way. They explored network concepts to design metamaterials exhibiting negative compressibility transitions, during which a material undergoes contraction when tensioned (or expansion when pressured). Continuous contraction of a material in the same direction of an applied tension, and in response to this tension, is inherently unstable. They achieved a conceptually similar effect, however, through destabilizations of (meta)stable equilibria of the constituents. These destabilizations give rise to a stress-induced solid-solid phase transition associated with a twisted hysteresis curve for the stress-strain relationship. The strain-driven counterpart of negative compressibility transitions is a force amplification phenomenon, where an increase in deformation induces a discontinuous increase in response force. The proposed materials are the first to exhibit longitudinal negative compressibility at zero frequency. They could be useful for the design of actuators, force amplifiers, micromechanical controls, and protective devices.

Zack, an undergraduate physics student working with Prof. Motter when the work was done, now is a first-year graduate student at Caltech.

The paper was published in Nature Materials and is available here.

A news story prepared by the NU NewsCenter is available here.

The Northwestern Newscenter has published an interview with Drs. Mayda Velasco and Michael Schmitt. Dr. Velasco reported that, "We are definitely entering a new era in particle physics." Read more about the discovery at the Northwestern Newscenter.

For a more in-depth look at the data from the LHC, check out Dr. Michael Schmitt's discussion of the new particle at his blog.

The Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) presented their preliminary results on the search for the standard model (SM) Higgs boson in their data recorded up to June 2012.

CMS observes an excess of events at a mass of approximately 125 GeV with a statistical significance of five standard deviations (5 sigma) above background expectations. The probability of the background alone fluctuating up by this amount or more is about one in three million. The evidence is strongest in the two final states with the best mass resolution: first the two-photon final state and second the final state with two pairs of charged leptons (electrons or muons). We interpret this to be due to the production of a previously unobserved particle with a mass of around 125 GeV.

The Northwestern's CMS team is headed by Mayda Velasco and Michael Schmitt, and originally formed by Bruno Gobbi.

The Northwestern CMS team  is involved in several Higgs analyses. Most of them look for decays that include at least one Z boson  in the final state or di-leptons with missing energy.  Our main emphasis now will be to understand the properties of this new resonance and look for other like it.  The PhD students supervised by Velasco that are working on Higgs related analysis as part of PhD thesis work are: Nate Odell, Andrey Pozdnyakov and Brian Pollack.  Other group members also working on Higgs and Electro-Weak physics are: Anton Anastassov, Andy Kubik, Radek Ofierzinsky, Stoyan Stoynev and Steve Won.

From the 24th to the 29th of June, Prof. Kamal Seth hosted the June 2012 PANDA collaboration meeting. Approximately 70 physicists attended.

The PANDA experiment (anti-Proton ANniliation at DAarmstadt) is being built at the Facility for Antiproton and Ion Research (FAIR) at the GSI Laboratory in Darmstadt, Germany.  The collaboration consists of more than 450 scientists from 17 countries, and is building a state-of-the-art detector to study the results of proton-antiproton collisions in order to study the strong nuclear force, exotic states of matter and the structure of hadrons.

Read more about the experiment and collaboration members here.

Prof. Eric Dahl is part of a group of physicists that has just launched an unusual new experiment in an attempt to be the first to directly confirm the existence of dark matter.

He spoke with the Northwestern Newscenter recently about his research.  Read the full article here.

Prof. Ian Low served as co-chair of our conference, "The Next Stretch of the Higgs Magnificent Mile."  The conference took place on our Chicago Campus, from May 14th to 16th. 

For more information, see the conference page here.

Prof. Anupam Garg's new graduate-level textbook, "Classical Electromagnetism in a Nutshell," has been published.  Reviewers call it "a treasure trove of thoughtful and incisive nuggets," and "the best treatment of electromagnetism in material media that I know."

"Classical Electromagnetism in a Nutshell" is also available in ebook format. 

Learn more from reviews from at Princeton University Press.

Physics World's Top 10 Discoveries of 2012 featured the MINERvA collaboration, which includes Northwestern Prof. Heidi Schellman, Postdoc Laura Fields, and Grad Student Cheryl Patrick.  Physics World recognized MINERvA for "being the first to demonstrate communications using neutrinos."

New results announced at Fermilab on March 2nd have given the most precise measurement of the W Boson to date - 80.387 GeV, plus or minus 0.019 GeV. Prof. Heidi Schellman, whose team contributed to the new measurement, reports that this new data will help narrow down the search for the much sought-after Higgs Boson.

 Read the full story at the Northwestern Newscenter here.

We are happy to announce that Michael Smutko has accepted a full-time Distinguished Senior Lecturer position in the Department starting this Spring. He will be teaching both physics and astronomy courses. For the past eight years, Michael has held a joint appointment with the Adler Planetarium. We are delighted that the Department will now be able to benefit more fully from his expertise.

In a campus-wide vote, Distinguished Senior Lecturer Michael Smutko has been elected by students to Northwestern's Associated Student Government's 2012 Faculty Honor Roll.  This marks the 5th year in a row that Dr. Smutko has received this honor and it is his 6th election overall.