Fermilab Today

Representatives from the Chicago Innovation Exchange will host office hours at the Illinois Accelerator Research Center on Thursday, June 11, 1-4 p.m.

Chat with experts about programs and services available through the Chicago Innovation Exchange, including the Innovation Fund, NSF I-Corps, Entrepreneurship Essentials workshops, how to protect your intellectual property and more.

Email Wolfgang Connell directly to make an appointment, or stop by IARC anytime between 1 and 4 p.m. to ask your question, talk about your idea or chat about the opportunities available.

A second set of office hours will be held on Tuesday, July 7, at IARC.

For more information, contact Wolfgang Connell, Chicago Innovation Exchange, or Jason Pariso, Innovation Fund.

From symmetry

LHC arrives at the next energy frontier

Data collection has officially begun at the Large Hadron Collider. Photo: Maximilien Brice, CERN

[On Wednesday] the Large Hadron Collider began collecting data for the first time in two years.

The world's most powerful particle accelerator powered back on in April and saw its first record-energy collisions in May. Today it began colliding particles at a steady rate to provide data for research.

This time around, the LHC is colliding particles at 13 trillion electronvolts, a 60 percent boost from its 2012 record of 8 TeV.

"Because we have higher energy, more particles are produced more frequently," says Beate Heinemann, ATLAS deputy spokesperson and physicist at the University of California in Berkeley at Lawrence Berkeley National Laboratory. "We will be able to test theories we've never been able to test before."

Inside the LHC, highly energetic protons collide and briefly convert their energy to mass. This produces other particles. The higher the amount of energy in the collisions, the more massive the particles they can produce. Physicists discovered the Higgs boson in 8-TeV collisions; there may be more to come at 13 TeV.

Notably, many scientists hope to discover supersymmetry, a theoretical model that predicts more massive partner particles for each known fundamental particle.

Also on the roster of potential discoveries are dark matter particles. Scientists have seen evidence that most of the matter in the universe is dark matter, but they have never knowingly produced it in the laboratory.

—Katie Elyce Jones

In Brief

LHC Physics Center celebrates second run of Large Hadron Collider

LHC Physics Center coordinators Meenakshi Narain, left, and Boaz Klima present cake and a 3-D model of the CMS detector at a celebration of the LHC restart. Photo: Jesus Orduna

On Wednesday, the LHC Physics Center hosted about 120 people in a celebration of the restart of the Large Hadron Collider.

Now equipped to collide particles at 13 trillion electronvolts, the LHC will probe the makeup of our universe at almost double the energy of its first run, which concluded two years ago. The beginning of physics data collection for LHC Run 2 is a milestone achievement, and members of the LHC Physics Center, the hub for U.S. physicists in the CMS collaboration, look forward to the new physics it will unveil.

LPC users celebrated on the 11th floor of Wilson Hall. Photo: Jesus Orduna

In the News

Can the U.S. work well with international partners?

From APS News, June 2015

The consensus among policy makers at the 2015 APS April Meeting in Baltimore is that large international collaborations are the future of "Big Science" research projects. However, arriving at the best role the United States can play is complicated.

Right now the Department of Energy (DOE) is putting together the Deep Underground Neutrino Experiment, the first major international physics collaboration hosted on U.S. soil. Those in charge have been looking to other collaborations as a guide for how to manage current and future international projects in the United States.

"The trend now is to do these big science projects internationally," said Nigel Lockyer, the director of Fermilab. "The trick for us here in the U.S. is we need to start to understand how we will host an international science facility on U.S. soil."

Frontier Science Result: CDF

Studying double W's at the Tevatron

Estimated and observed distribution for our algorithm, which is used to identify WW events. High values of NN indicate a more signal-like event.

In a recent measurement, the CDF experiment studied in detail events with two massive W vector bosons produced with associated jets (a spray of particles resulting from an energetic quark or gluon). These types of events are widely considered to be a window for looking for physics beyond the Standard Model.

Each W can decay into a charged lepton (an electron or a muon) and a neutrino, which has no charge. So to identify the production of W pairs, we look for two leptons (one from each W) with high momentum transverse to the beam and missing transverse energy (accounted for by the neutrinos). We also have to rule out the dominant backgrounds, the three main sources of which are top quark pair production, Z decay into leptons with mismeasured transverse energy and single W production with a misidentified second lepton.

This measurement is made possible by the relatively low energy of the Tevatron, which results in a manageable production rate for pairs of top quarks, the dominant background for events with two W bosons and two or more jets. This analysis measures for the first time the rate of production of W boson pairs as a function of the energy and multiplicity of associated jets.

Events are classified by the number of jets and transverse energy. Those with two or more jets are vetoed if they are found to contain a bottom quark, which is typical of top quark decay, one of our background culprits.

Advanced mathematical techniques called neural networks exploit features of the signal and background to further distinguish signal events while preserving efficiency.

The upper figure shows a result of a fit to the WW signal and the expected backgrounds. The results as a function of the number of jets are found to be consistent with the Standard Model prediction, as shown in the lower figure.

The CDF study demonstrates for the first time the validity of commonly used simulation techniques to model events with multiple vector bosons and additional jets. The result can also be directly compared to new simulation techniques, essential to searches for physics in the coming LHC run and beyond. If new physics is not directly observed in the upcoming second LHC run, evidence could appear indirectly in the scattering of massive vector bosons such as the W. An analysis like this one could be performed at the LHC and result in a much larger yield of events than predicted by the Standard Model. It would be a very difficult measurement because of large backgrounds at a high-luminosity 13-TeV LHC.

Nevertheless, such a measurement could be a handle on new physics, perhaps extra-dimensional models, new gauge bosons or new Higgs models.

—Will Parker and Andy Beretvas

Learn more

Measurement and predictions (ALPGEN and MCF@NLO) for σ(pp → W⁺W^- + njets). The one jet bin is also subdivided into transverse energy ranges of (a) 15 < E_T < 25, (b) 25 < E_T < 45, and (c) E_T > 45 GeV.

Matt Herndon and Will Parker, both from the University of Wisconsin, are the primary analysts for this result.

Photo of the Day

Converging lines

Road A stretches toward the horizon. Photo: Valery Stanley, WDRS

In the News

Large Hadron Collider starts doing science again

From Nature, June 3, 2015

The highest-energy collisions ever seen at the Large Hadron Collider (LHC) are now producing data for science.

Teams at CERN, Europe's particle-physics laboratory near Geneva, Switzerland, have spent two years upgrading what was already the world's most powerful particle accelerator. At 10.40 local time this morning (3 June), they officially set the newly supercharged collider running.

Physicists can now smash together bunches of protons at a record energy of 13 teraelectronvolts (TeV) and will soon collide a billion pairs of protons per second — almost double the previous rate. The machine was switched off on 14 February 2013 after an initial period — dubbed run 1 — marked by the discovery of the Higgs boson.