Burst of LHC collision data a welcome birthday gift

December 16, 2009 | 1:58 pm

After being blasted in the media for machine problems last year just hours after its turn on and then a power outage this year caused by a rogue bird dropping a baguette onto electrical equipment, physicists have been eager to prove to the world the Large Hadron Collider isn’t a lemon.

This week they did just that.

Attending a symposium at Fermilab in honor of theorist Chris Quigg’s 65th birthday, ATLAS experiment co-spokesperson Fabiola Gianotti ended up talking about brand new ATLAS data. It wasn’t planned that way, but a burst of beam and steady stream of more than two hours of data in the wee hours before the talk provided a unique and excellently timed opportunity.

Her excited, and proud, utterance to the crowd that they would get “no simulations, no Monte Carlo, just data” in her talk brought booming applause.

On December 8, the four large LHC experiments recorded 3 minutes of world record-breaking energy collisions of 2.36 TeV, the maximum energy threshold for operation in 2009. But the December 14 rush of data was the first time that LHC experimenters got a sustained amount of data at energy levels beyond that of the Tevatron. Monday’s data run was the real test for the detectors and collaborators, proving the detectors’ quality constructions and the collaborations’ speedy communication systems. Within a couple hours of run time, ATLAS was able to record 1200 events and CMS 3600 events.

“It took more than 20 years of effort by the worldwide physics community to get to this fantastic moment,” she said. “I think this is a good sign that things are under control.”

The success took on extra meaning because Quigg has been involved in much of the theory work that defines the LHC research program and he wrote the book Gauge Theories of the Strong, Weak and Electromagnetic Interactions that many physicists, including Gianotti considered “a bible” during their early research years.

“Thank you for this wonderful birthday present and my respect and gratitude to everyone on ATLAS and at CERN for making this happen,” Quigg told Gianotti.

Jet event from ATLAS Dec. 14 at 2.36 TeV

The large dataset points to a finely tuned machine and well laid out data distribution system.

Both experiments have analyzed a multitude of data at the lower 900 GeV energy level and found it agrees with Monte Carlo simulations, meaning the machine is tracking and recording data as expected.  By the time of Gianotti’s talk just seven hours after the 2 a.m. new record breaking collisions, ATLAS also had analyzed some of new data, finding similar agreement.

Physicists were able to record their first photon to electron and positron conversion, the first muon candidates, and to measure the total missing transverse energy, a key sign that researchers are able to mitigate background signals.

Collaborators on ATLAS and CMS have been extremely fast in culling data from their detectors at both low and high energies as well as sending it to universities across the globe through a tiered system of computer grids.

“In some cases, we got results in a few hours,” Gianotti said. “The enthusiasm and team spirit in the collaboration is extraordinary.”

Tona Kunz

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This week at the LHC

December 15, 2009 | 10:33 am

A dimuon event recorded by CMS on December 14.

The LHC had a successful weekend, with the experiments recording a total of 50,000 collisions at 2.36 TeV, the LHC’s maximum energy for 2009. Collectively, the six LHC experiments saw over one million collision events at 900 GeV, which also provided enough data to characterize the accelerator. Last night, the LHC circulated the highest intensity beams yet, with 16 particle bunches per beam. Each bunch contained approximately 20 billion particles.

The weekend’s collision events are an exciting confirmation of the machine’s abilities, but there is still a long way to go. This year’s LHC run ends this week. The LHC will restart in the first quarter of 2010, following maintenance and hardware preparation for the next milestone, collisions at an energy of 7 TeV (3.5 TeV per beam).

“Our main goals for this year were to fully characterize the machine, have collisions at whatever energy to prove that they are feasible, and to try to increase the energy. Things for this year are on schedule,” explains Mirko Pojer of LHC operations. “To reach 7 TeV next year will be again a huge effort but increasing energy this year was easier than anybody was expecting. Ramping up in energy went very well.”

At the moment, many beam injections are essentially pilot runs. A beam with one particle bunch is sent around the ring at a low energy and intensity to probe that it can traverse the ring smoothly and that the entirety of the LHC is operating as one. In addition, the longevity of the beam is studied to assess how long the particles can circulate before decaying.

As plans are made to increase the accelerator’s energy and intensity in 2010, the balance of protecting the machine and maximizing scientific potential remains at the core of the decision-making process. The LHC will be switched off on December 16. CERN will close from December 19 to January 4. Following a period of hardware preparation and maintenance, the LHC will ramp even higher in energy, aiming for collisions at 7 TeV in the first quarter of 2010. The intensity will also be increased to the ultimate goal of 2808 proton bunches per beam, with 100 billion particles in each bunch.

Further LHC reading/viewing:

• On Friday, December 18 at 6:15 a.m. Eastern time, the second public status report on the progress of the LHC and experiments will take place in CERN’s Main Auditorium. The seminar will be webcast.
• The ATLAS e-news provides an experiment’s perspective of the events over the last three weeks, plans for the next two months, as well as explaining what scientists are doing with these first LHC collisions at low energy.
• You can follow events seen by CMS on their e-commentary, read more on CMS Times, and view event displays on the CMS public website

by Daisy Yuhas

Symmetry Intern

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Fueling the future: Using accelerator-driven systems to recycle nuclear waste

December 14, 2009 | 11:28 am

The superconducting radio frequency technology that Fermilab scientists are helping to develop could one day pave the way to cleaner nuclear power.

In October, Fermilab hosted physicists and engineers from around the world at the Workshop on the Applications of High-Intensity Proton Accelerators to consider this idea and others.

In this video, three attendees of the international workshop discuss the potential benefits of using accelerator-driven systems to produce fuel and recycle nuclear waste. Srikumar Banerjee of the Bhabha Atomic Research Center in Mumbai; Alex Stanculescu of International Atomic Energy Agency in Vienna; and Rajendran Raja of Fermilab offer their perspectives.

The Fermilab workshop served as a precursor to the Symposium on Accelerators for America’s Future in Washington, DC. See the meeting agenda and watch videos of presentations from the symposium here.

Kathryn Grim

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FlashForward: science fact vs. science fiction

December 11, 2009 | 1:37 pm

The cast of ABC's TV series FlashForward. (ABC/Bob D'Amico)

In the December 3 episode of ABC’s FlashForward television drama, researchers from a fictional research organization called the National Linear Accelerator Project, purportedly located in Palo Alto, California, announced that they might have caused the worldwide blackout that killed 20 million people by conducting “proton-driven plasma-wakefield acceleration” experiments.

While this makes for enthralling TV, it’s definitely not reality TV.

Researchers at the real-life SLAC National Accelerator Laboratory, located very close to Palo Alto, California, do indeed conduct electron-driven plasma-wakefield experiments—but, fortunately, there’s no chance their experiments will lead to death and destruction.  Instead, plasma-wakefield experiments may lead to a less costly, more efficient means of accelerating particles to greater energies in the estimated 17,000 particle accelerators in everyday use around the world. These accelerators play a key role in basic science research, medical technologies, industrial processes, food preparation, and environmental cleanup—to name just a few applications.

To help viewers distinguish science fact from science fiction in the TV episode, SLAC has posted a Q&A on its Web site. Readers can also learn more about the science behind plasma-wakefield acceleration in October’s edition of symmetry magazine, and about the FlashForward series in three recent symmetry stories:

The science behind FlashForward
FlashForward author Robert J. Sawyer on the LHC, Higgs, and Hollywood
FlashForward: More on the science behind the story

Kelen Tuttle

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The search for dark matter: has CDMS found something?

December 10, 2009 | 4:08 pm

CDMS project manager Dan Bauer adjusts elements of the CDMS detector.

Update: The CDMS announcement is covered in detail a newer story.

There are many rumors circulating about upcoming results from the CDMS experiment. A statement from the CDMS collaboration helps to set the record straight:

The CDMS collaboration has completed the analysis of the final CDMS-II runs, which more than doubled the total data from all previous runs combined. The collaboration is working hard to complete the first scientific publication about these new results and plans to submit the manuscript to arXiv.org before the two primary CDMS talks scheduled for Thursday, Dec. 17, at Fermilab and at SLAC.

Fermilab physicist Lauren Hsu will present a talk on the new results at Fermilab on Thursday, Dec. 17 at 4 p.m. CST. A Webcast will be available here.

Also on Dec. 17, at 2 p.m. PST, Southern Methodist University physicist Jodi Cooley, CDMS analysis coordinator, will speak at SLAC. Her talk will be Webcast on the CDMS Web site.

When collaborators opened the black box nearly two years ago they didn’t see any candidates for dark matter particles, but they did set the world’s best constraints on the properties of dark matter candidates, another step forward in the search.

The CDMS experiment is located a half-mile underground in the Soudan Underground Laboratory in northern Minnesota, shielded from cosmic rays and other particles that could mimic the signals expected from dark matter particles.

Learn more about dark matter and the CDMS experiment on this FAQ Web page from the 2008 press release. An article in symmetry magazine features Jodi Cooley and explains how scientists use the CDMS experiment to listen for whispers of dark matter.

View photos and video related to the CDMS experiment in the CDMS image gallery from 2008.

Rhianna Wisniewski

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CERN celebrates 50 years of high-energy physics

December 10, 2009 | 1:18 am

"From the Proton Synchroton to the Large Hadron Collider- 50 Years of Nobel Memories in High-Energy Physics" Symposium at CERN on December 3 and 4.

On December 3 and 4, CERN held a two-day symposium to celebrate the past fifty years in high-energy particle physics. The event, titled “From the Proton Synchroton to the Large Hadron Collider–50 Years of Nobel Memories in High-Energy Physics,” coincided with the fiftieth anniversary of the PS, the Proton Synchroton; twentieth anniversary of LEP, the Large Electron-Positron collider; and the restart of the LHC. Speakers at the symposium, including thirteen Nobel Laureates, discussed developments in high-energy physics over the last fifty years and what’s to come, from the LHC to linear colliders and beyond.

The first day of the symposium focused largely on accelerator physics, looking back and highlighting the trials and triumphs of particle accelerators and the people who built them. The Proton Synchrotron, or PS, which began operation in 1959, was CERN’s first synchrotron and remains a vital part of the CERN accelerator complex today. LEP, which was the largest accelerator of its time when it began running in 1989, tested theoretical predictions of the Standard Model, set a lower limit for the Higgs Boson’s mass, and established the existence of three types of neutrino.

The long history of the LHC, LEP’s successor, was discussed by Lyndon Evans in his presentation “The LHC Adventure.” He noted, “This machine is a beautiful machine and frankly, it feels more like an old friend than a new machine.”

The formation and scope of CERN as an international organization was also discussed. Guenther Plass mentioned the sixtieth anniversary of Louis de Broglie’s request for an institution that would operate beyond the framework of its member states, and Burton Richter called for greater collaboration in the future. Richter closed his presentation with the opinion that only two places had the potential to host a multibillion dollar linear collider, CERN or China. Richter stressed, however, that CERN would only remain at the forefront by internationalizing further.

Director General Rolf Heuer closed the first day’s talks with a forward look, including LHC upgrades and future colliders such as the ILC or CLIC.

The second day of the symposium focused on the development of the broader field of particle physics, and the development and testing of the Standard Model. By examining the differences between physics as it was in 1959, and particle physics today, the speakers provided a window into not only how much has changed within fifty years but also insight into the process of discovery itself.

In his comparison of old and new physics, Gerardus t’Hooft marveled at the elegance and beauty of nature as revealed in each new discovery. While discussing the standard model, he remarked on how dramatically perspectives in physics have changed with new discoveries: “Could we have expected such a beautiful theory in the 1960s? I think no one could have expected such a grand synthesis.”

Personal experience woven into the presentations created a layered history of scientific progress. Sheldon Glashow focused on the “road to electroweak unification,” incorporating “false starts and bumbling blunders, mostly mine, and a few brilliant insights,” to reveal the importance of both error and success in scientific discovery.

Questions were also generated by looking at the past. David Gross challenged that “Standard Model” was a misnomer and that standard theory would be a more appropriate title. Opinions also varied on the relative relevance of string theory and supersymmetry to future physics discoveries and the LHC. Martinus Veltman focused on the efforts thus far to find the Higgs boson and what steps should be taken if the LHC experiments do not detect the Higgs. A recurring theme in the presentations was a willingness to pursue possibilities and to question everything.

“We really make progress when we recognize good ideas, whether we make them or not,” observed Jim Cronin. This sentiment was palpable in the symposium, as the people who had pursued good ideas shared their stories and offered advice for the future. It was evident that, as CERN looks forward to future physics discoveries with the LHC, the lessons of the past fifty years will not soon be forgotten.

Full video coverage of the symposium is available online at http://cdsweb.cern.ch/record/1227015/. Highlights include:

- Part 1: Guenther Plass’s “The PS Machine: 50 Years of Continuous Evolution,” and Dr. Steve Meyer’s “LEP Operation”

- Part 2: Burton Richter’s “Electron Accelerators at CERN,” Lyndon Evans’ “The LHC Adventure” and Rolf-Dieter Heuer’s “The Future of the CERN Accelerators Complex”

- Part 3: Jim Cronin’s “The Discovery of CP Violation: a Surprise” and Sheldon Glashow’s “Unification: Then and Now”

- Part 4: Martinus Veltman’s “The LHC and the Higgs boson”

- Part 5: Gerardus ‘t Hooft’s “The Unique Beauty of the Subatomic Landscape,” David Gross’ “QCD: Now and Then,” and Steven Weinberg’s “Changing Views of Symmetry”

by Daisy Yuhas

Symmetry Intern

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The latest from the LHC

December 9, 2009 | 8:18 am

Last night the first collisions of protons at the world-record energy of 2.36 TeV (1.18 TeV per beam) were recorded by the ATLAS experiment at CERN. The ATLAS team posted an image of one candidate collision event on its Web site.

In addition to setting world records–for proton beam energy on November 29, and last night for proton collision energy–the team operating the Large Hadron Collider at CERN, and the teams operating the LHC experiments, have been hard at work. Here are a few more highlights from the last week and a half.

One of the main objectives for the LHC team over the past week and a half has been preparing to circulate and collide beams at higher intensities. This involves increasing the number of bunches that make up each LHC beam as well as the number of protons in each bunch.

“Higher intensity means more luminosity, more luminosity means more events for the experiments, more events gives more physics,” explained Fermilab’s Jim Strait, a former project manager for the US contributions to the LHC accelerator who has been at CERN for the last year and a half assisting with LHC commissioning.

At full intensity, LHC beams will have 2808 bunches each. The very first collisions at the LHC, at an energy of 450 GeV per beam on November 23, took place between one-bunch beams. On December 4, the LHC injected and circulated the very first two-bunch beam at an energy of 450 GeV. Around midnight on December 6, the first four-bunch beams were circulated and steered to collide in the center of the experiments.

Another main objective has been to deliver collisions at an energy of 450 GeV per beam to the LHC experiments. Collisions at this low energy–the energy at which the beams are injected into the LHC–are crucial to the experiments for calibrating and testing their detectors. The first sustained period of multi-bunch collisions at 450 GeV per beam occurred on December 6, and the experiments have continued to collect collision data at injection energy over the past few days.

The teams on the LHC experiments have been busily analyzing the first experimental data. The first LHC paper using collision data was prepared by the ALICE collaboration and accepted by the European Physical Journal C on December 1.

Although the LHC has already reached several milestones, there is much work still to do. By the time CERN shuts down for its two-week winter break on December 18, CERN hopes to have achieved a sustained period of collisions at an energy of 2.36 TeV. The next step will be collisions at a total energy of 7 TeV in early 2010, at which point the teams on the experiments will have their first chance to search for new physics.

“Almost all the work is still ahead to commission the machine and learn how to operate the beams,” said Strait. “They’ve only been at it two week. There’s been fantastic progress, but it’s still only two weeks.”

Katie Yurkewicz

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How a new muon experiment can advance physics

December 9, 2009 | 5:30 am

From left: Doug Glenzinski, Craig Group and Amy Allen work on a "straw detector" test stand at Fermilab. Photo Courtesy of Fermilab.

Tona Kunz

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DOE gives big boost to Fermilab’s plans for new muon experiment

December 8, 2009 | 6:19 am

From left: Amy Allen, Doug Glenzinski, and Craig Group work on the Mu2e experiment test stand at Fermilab. Mu2e just passed the first DOE approval stage. Photo Courtesy of Fermilab.

While all eyes have been on the startup of the Large Hadron Collider in Europe, the world’s largest scientific experiment, a small team of researchers based in the US has been toiling away.

The group has focused its energies on planning an experiment that creates a plenitude of muons and could reveal new phenomena that could only result from unknown physics.

That narrow focus, say the members of the Muon-to-Electron-Conversion experiment, will allow the Mu2e collaboration to indirectly search for new particles and let them look for signs of new types of interactions at energies up to 10,000 trillion electronvolts, far beyond the LHC’s grasp. It also would help scientists to better understand future LHC discoveries.

Mu2e got a big boost on November 24 with the US Department of Energy endorsement of the scientific need for the project, called Critical Decision-0. This marks the first stage of DOE’s 4-stage approval process that projects must pass before construction can start.

“Every CD is an important milestone.  CD-0 is unique in that most of the work is done by the DOE.  The fact that they put in the work to push this through is a clear indication that they are serious about Mu2e,” says Ron Ray, project manager.  “The ball is now in our court and we have a lot of work to do.”

The idea behind the Mu2e experiment isn’t new–the similar and well-reviewed Muon to Electron COnversion (MECO) experiment proposed at Brookhaven National Laboratory in Long Island was canceled in 2005 for lack of funding. But funding agencies and research experts say the time now is right for such an endeavor. The US Particle Physics Project Prioritization Panel, P5, recommended construction of Mu2e in any federal budget funding scenario and Fermilab’s Physics Advisory Panel, comprised of global experts in the field, endorsed it.

DOE approval makes Mu2e the only US-based charged-lepton flavor violation experiment. Similar experiments are proposed in Japan:  Coherent Muon to Electron Transition, COMET, a neutrino-less conversion of muons to electrons and its follow up experiment PRISM Muon to Electron Conversion experiment, PRIME, which uses a different design than Mu2e, and the complementary MEG experiment at the Paul Scherrer Institute in Switzerland that searches for muon decaying into electrons and photons.

Potential design of Mu2e. Courtesy Fermilab.

“This is a technically challenging experiment and this is an opportunity to build hardware. The LHC experiments are built,” Ray says. “For people who want to get involved in building something from the ground up and see the fruits of their labor in their lifetime this is an exciting project.”

Mu2e will introduce groundbreaking technological advances for superconducting solenoids and particle trackers.

The 100-member collaboration now can take on more members. Researchers come from 12 US universities; Muons Inc., a private US firm; Brookhaven and Fermilab, US national laboratories; and national laboratories and universities in Italy and Russia.

“A lot of the collaborators from Italy are the same that contributed over time to CDF,” Ray says. “We expect they will have the same impact on Mu2e that they had on [the Tevatron’s] CDF experiment, and that was substantial.”

Italy has primary responsibility for designing, building, and commissioning the calorimeter.

Mu2e has significant advantages over similar experiments. It will use the existing Fermilab accelerator complex with minor modifications once the Tevatron collider shuts down. Mu2e won’t interfere with the lab’s new flagship neutrino experiment, NOvA, which is under construction. The Fermilab accelerator complex produces more proton beam than NOvA can use, and Mu2e will use the excess.

Mu2e would use an 8 billion electronvolt, or 8 GeV, proton beam and a fixed target to generate a large number of muons and track whether they change into electrons.

The estimated total cost of the project is about $200 million.  Understanding the cost in more detail is one of the main goals of the project over the next year.

Collaborators are currently working on tracker and magnet prototypes and detailed simulations that should be complete by the summer.  This should allow the project to proceed to CD-1 by the spring of 2011 and operation in 2017.

Tona Kunz

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Particle physics gets hip with a party at the planetarium

December 7, 2009 | 8:30 am

Guests check out a display at Adler After Dark

“Some of you are just realizing,” Fermilab physicist Don Lincoln said to the crowd in the darkened lecture hall at Chicago’s Adler Planetarium, “you’re in a particle physics lecture… on a date.”

Lincoln gave a talk about the recently restarted Large Hadron Collider during Adler After Dark, the planetarium’s new after-hours program aimed at an audience that does not always find its way to the planetarium.

Many of the mostly 20- to 30-somethings that made up the crowd of just over 700 guests at Adler on Nov. 19 said they had grown up in the Chicago area and last visited the planetarium on a class field trip.

“People have fond memories of coming here as kids,” said Mike Smutko, astronomer and director of Adler’s observatory. “But they don’t come back until they have their own kids. We’re trying to capture that middle section.”

At Adler After Dark in November, DJ D-Rek spun dance music in the planetarium’s dining area next to floor-to-ceiling windows facing Lake Michigan and the Chicago skyline. Guests sipped wine or beer on the patio while training telescopes on Jupiter. They took in hors d’oeuvres and full-dome theater shows about the formation of the moon. And Lincoln, author of The Quantum Frontier, a book for the general public about the LHC, described to about 100 visitors how scientists at CERN planned to collide two beams of protons at nearly the speed of light.

One of the possible effects of turning on the LHC

Lincoln said that the most foolish question one can ask about experiments at the LHC is: “What are you going to find?”

“We don’t know what we’re going to see,” he said. “But we do know what we’re looking for.”

Scientists at the world’s largest experiment are seeking answers to questions such as: Why are there three dimensions? Could there be more? What gives particles their mass? Are there new forces and symmetries we haven’t observed? Will we find something deeper, a unifying principle?

The planetarium drew guests to Lincoln’s lecture with the title “The End of the World,” playing on news stories drumming up fears that turning on the LHC would destroy the Earth.

Lincoln cataloged in his talk many of the scenarios in which people have claimed that the particle accelerator will end our existence. It might cause strangelets or a black hole that would consume us all, people have said. It might create magnetic monopoles. As Lincoln illustrated by an animated slide, it might awaken Godzilla, who will destroy cities with lasers to the tunes of Blue Oyster Cult.

Lincoln answers questions after the lecture

“I could explain why each of these things won’t happen,” Lincoln said. “But what you need is something that will explain everything.”

The key, he said, was to look to cosmic rays, which can speed into the atmosphere at much higher energies than the proton beams in the LHC will ever achieve.

The universe is constantly bombarding the Earth with cosmic rays, which are primarily protons. The atmosphere, just 20 miles above our heads, is made up of protons and neutrons. High-energy collisions between protons from cosmic rays and those that make up the atmosphere have been going on for 4 billion years. And the Earth is still here; these collisions have not caused a strangelet or a magnetic monopole or an Earth-swallowing black hole.

Lincoln’s conclusion: “After the lecture, go and get a drink. We’re going to be okay.”

Adler After Dark occurs the third Thursday of every month. Tickets for the general public cost $10 if purchased in advance or $15 at the door.

Kathryn Grim

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