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In this issue:
Stand and Deliver
Science Today: Quirky New Physics Signals at the LHC
Layoff Support Services

SLAC Today

Thursday - February 7, 2008

(Left to right) Don Schafer, Kay Fox, Tim Montagne, Bob Perry, Rick Jackson and Mike Palrang with a set of newly arrived support stands for the LCLS. (Click on image for larger version.)

Stand and Deliver

Last week, trucks arrived with the first shipment of specially designed stands for Linac Coherent Light Source (LCLS) magnets and diagnostics to be installed in the Beam Transport Hall. This section of the LCLS, called the "linac-to-undulator," will connect the end of the linac to the undulator magnet arrays. Preparation for installing the stands is starting now as construction on the Beam Transport Hall nears completion.

All together there are more than 200 stands, with the heaviest weighing over half a ton. But for now, only a handful of the stands are on site, and the vendor will store the rest until they are needed simply because of the sheer mass of steel involved. Tim Montagne, the LCLS team leader in charge of the design effort for the stands, said that as a first step toward readying the hardware for installation, a few of the stands were shipped for test fitting of all the representative large magnets.

The stands themselves are engineered to virtually eliminate motion due to vibration from things like ventilation fans, circulating cooling water or nearby traffic. The specifications require that the magnets can move no more than 50 nanometers, a distance smaller than the size of a single virus.

"What you're seeing represents about one year of work," said Montagne.

(Daily Column - Science Today)

Quirky New Physics Signals at the LHC

The CERN Large Hadron Collider (LHC) is turning on this year and the high energy physics community is holding its breath. This new particle accelerator, 27 kilometers in circumference, promises to unveil the secrets of the electroweak scale. It will teach us why particles have mass and what, if anything, lies beyond the Standard Model. For the past two decades theorists have speculated as to what we will see when we flip the switch, proposing thousands of models of new physics. Over the years, several of these have achieved more prominence than others. Today, theories such as supersymmetry and extra dimensions are generally considered the most promising candidates for new physics. However, the truth is that we do not know what we will see.

For this reason, we need to be prepared for anything. The range of possible signals at the LHC is nearly as wide as the range of models and there are many signals we might miss if we're not looking in the right place. That is why Roni Harnik and I are studying a class of models that present an especially unique and challenging signal. These theories, known as hidden valley models, involve a hidden sector coupled weakly to the known particles of the Standard Model. Moreover, the particles in the hidden sector—the valley particles—are coupled to each other through strong interactions much like the quarks in a proton. There are many possibilities for what happens next. Matthew Strassler and Kathryn Zurek, of the University of Washington, who introduced the hidden-valley idea, studied the case in which the bound state falls apart into hidden-valley pions. These slowly decay to pairs of heavy quarks, producing weird events with multiple b quarks and vertices meters from the interaction point.

Harnik and I studied a different scenario in which there are no light hidden mesons. In this scenario, the particles in the hidden valley—we call them "quirks"—begin by flying away from each other, propelled by the energy of the collision. However, the strong force connecting them will eventually stop the outward motion and send them flying back. The quirkantiquirk pair goes through rapid oscillations. If the quirks are electrically charged, this oscillator will radiate photons like an antenna. The typical energy of the photons is a few hundred MeV, and about a thousand such photons might be created. In combination with the quirk annihilation products, this might be a signal that could be recognized and observed at the LHC. We computed the radiation pattern of the photons; this characteristic pattern might be observed in the data.

The class of models we considered is special, but our conclusions are rather general. Soft diffuse photons can be a viable signature of new physics. Moreover it is a signal that is easily missed if we are not prepared for it. New physics may appear at the LHC in spectacular unmissable ways, giving signatures like this less importance. However, nature may not be so kind. The first signals of new physics could well be fleeting and obscure. It is imperative that, when trolling the immensely complex event records that will pour out of the LHC detectors, we cast as wide a net as possible.

Layoff Support Services

During this difficult time, SLAC is offering several areas of support to the employees that the lab has laid off due to the FY08 budget.

The majority of these services will be offered through Peninsula Works for bargaining unit employees and DBM Career Services for non-bargaining unit employees. Both companies offer very similar programs including resume assistance, interviewing skill seminars, networking meetings and job search workshops. Both Peninsula Works and DBM will come to SLAC to give presentations in the coming weeks and can be contacted directly via their websites.

In addition, the State Employment Development Department will offer two presentations about unemployment insurance benefits over the coming weeks. These talks will cover the application process as well as how to remain in good standing and ensure that you receive your full benefit. When firm dates and times for these presentations are set, they will be posted to the Layoff Information website.

The January layoff announcement produced a response from companies interested in displaced SLAC workers. A list of these companies is being compiled and will appear on the SLAC Layoff website. In mid-March, SLAC will host a job fair to connect both voluntarily and involuntarily displaced workers with local interested businesses. The exact date of this fair has not yet been determined, but it too will be posted to the Layoff Information website as soon as it is known.

In addition, both voluntarily and involuntarily displaced workers will receive a layoff preference when they apply for other employment at SLAC and on the Stanford main campus. To take advantage of this preference, please notify the SLAC Employment Services Office if you apply for a Stanford or SLAC position.

SLAC continues to offer counseling via the Stanford Faculty and Staff Help Center. All displaced employees will continue to have access to this service for themselves and their family members for as long as they are covered by COBRA. If you need help during this transition period, please do not hesitate to contact the Help Center.

More information on all of these programs can be found on the continually updated Layoff Information website.


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