News Update From Associate Laboratory Director Steve Vigdor

April 22, 2010

I would like to bring you up to date on several issues: progress on the ongoing RHIC Run 10 and RHIC’s recent science impact; progress on collider improvements; budget outlooks for the next few years; the new decadal plans currently being developed by PHENIX and STAR Collaborations; and traffic safety on-site at BNL.

The RHIC Run and Science Impact

RHIC is so far having an outstanding FY2010. Analysis of data from previous runs has led to a steady stream of new publications and presentations, with results attracting broad international attention from both the physics research community and the media. Publications in the winter of Physical Review Letters on new PHENIX and STAR heavy-ion collision results prompted press releases and a press conference at the Washington APS meeting in February. PHENIX measured the early collision temperature via thermal di-electron cross sections, while STAR measured azimuthal charged-particle correlations relevant to predictions of local parity violation. The press releases generated enormous interest, with significant coverage in well over 500 international print and online articles, a number of radio, television and film interviews, and nearly 100,000 views to date of the YouTube video animation that accompanied the releases.

An international workshop on P- and CP-Odd Effects in Hot and Dense Matter at BNL April 26-30 will expose the intense scientific interest this subject is generating in the wake of the STAR results. Additional press coverage accompanied the publication in Science of the STAR discovery of the anti-hypertriton. New d+Au results from Run 8 presented at recent conferences provide additional strong evidence in support of saturation of gluon densities in the colliding cold nuclei. First W production asymmetries measured in 500 GeV polarized proton collisions in Run 9 were presented at the February APS meeting, demonstrating RHIC’s capabilities for future illumination of sea antiquark polarizations in the proton. The science program is cooking efficiently on all burners right now!

The ongoing Run 10 is devoted to Au+Au collisions over a wide range of energies, providing yet another demonstration of RHIC’s versatility. The collider and detector performance have so far been excellent, allowing us to reach or exceed science goals so far at center-of-mass energies of 200, 62.4 and 39 GeV per nucleon pair. A significant focus at these energies has been on measurement of dielectron spectra in PHENIX while the Hadron Blind Detector is still installed (it will be removed in Summer 2010 to allow installation of the VTX upgrade), greatly suppressing Dalitz decay and photon conversion backgrounds. We are just about to move on to 7.7 GeV, the lowest energy yet attempted in RHIC, to get a healthy start on measurements aimed to search for a possible critical endpoint in the QCD phase diagram. If all continues to go well, we will also be able to continue the beam energy scan at 11.5 GeV. For the first time in quite a few years, both the operating budget and the timeline on which it was delivered were sufficient to support a run of nearly optimal length (28 cryo-weeks in all), and we anticipate a significant payoff in scientific productivity.

Collider Improvements

It has also been a very good year for progress on machine performance. Transverse stochastic cooling of bunched high-energy beams was demonstrated for the first time early in the run. Four planes of stochastic cooling systems (pickups plus kickers for longitudinal and vertical corrections in both rings) were commissioned during the 200 GeV portion. While basic functionality of the cooling systems was clearly demonstrated, several systems developed leaks or cooling problems that will have to be addressed by retrofits during the Summer 2010 shutdown. Not all systems may be back in place for Run 11, but we anticipate six planes of cooling (adding horizontal transverse systems for both rings to the present ensemble) installed for RHIC Run 12. One thing clearly learned this year is that all of the systems must be operating simultaneously for optimal gain in time-averaged luminosity. In part, this is because the transverse emittances of the two beams must be relatively closely matched, lest the smaller beam lead to blow-up of the larger one. In addition, longitudinal cooling must remain in effect to limit the tendency of transverse cooling to push beam gradually into neighboring RF buckets. With 6 planes in effect in Run 12, we anticipate even faster cooling than observed in Run 10, and with the further addition of the 56 MHz superconducting RF cavities for rebunching in Run 13 we expect the RF bucket and time distributions of the beams to remain sharp for a longer time.

We have also managed to make progress relevant to polarized proton performance during a run dedicated exclusively to heavy-ion collision running. The most severe limitation on 500 GeV pp collision performance in Run 9 arose from relatively poor (~70%) polarization transmission from injection energy to 250 GeV beam energy. We demonstrated in Run 9 that this characteristic could improve considerably if we could stably operate the machine closer to the 2/3-integer betatron tune, without risking beam loss from close approach to this resonance. Main magnet power supply stability and ramp improvements placed in effect during the Summer 2009 shutdown have now been tested by demonstrating (with Au beams) that we can reliably operate at tunes within 0.005 of the resonant condition. We anticipate that this should produce at least 90% polarization transmission to maximum energy. We have also been working behind RHIC stores to commission AGS tune jump quadrupoles to improve polarization transmission through the AGS acceleration.

Budget Outlooks

The RHIC operations budget in FY10 has been healthy, and the power costs have remained moderate, permitting a significantly longer run than we have managed over the preceding four years. The President’s request for FY11 includes a good budget for the Office of Nuclear Physics at DOE, and would support a 30-cryoweek run. However, the large national deficit coupled with an election year make it likely that Congress may reduce this budget, and also that there may be a significant period of Continuing Resolution in FY11. We will maintain sufficient carry-over funds from FY10 to permit a relatively early start on Run 11, unless we anticipate a very long delay in receiving a budget. In addition, ongoing negotiations for a new power contract with New York State promise to keep RHIC power costs under control for an extended period. I will keep you up to date as we learn more about Congressional action on the budget.

For FY12-13, we are told to anticipate quite tight budgets for basic research not directly connected to national needs in energy and climate, so we may well see somewhat shorter RHIC runs during those years. In addition, the need to accommodate FRIB construction may well have impact on the length of RHIC runs in the out-years. I believe that the spate of recent press interest in RHIC results, though not premeditated for this purpose, has turned out to be quite timely in emphasizing the facility’s continuing productivity and impact at a time of difficult budget planning and choices. We need to continue to make a strong public case for the importance and relevance of RHIC’s upcoming science goals.

New Decadal Plans

Part of making the continuing science case for RHIC is updating the STAR and PHENIX decadal plans, originally drafted about seven years ago. Many of the detector upgrades proposed in those plans have now been funded and are or will be soon installed. We need to understand, and DOE would like to know, what comes next. Are there further compelling upgrades to the existing detectors needed beyond 2015, and if so, what new and otherwise unattainable science impact are they likely to deliver? Do the PHENIX and STAR Collaborations envision playing a role in e+p and e+A collisions at an Electron-Ion Collider, and if so, in what ways could existing detector subsystems and infrastructure be reused? These are among the questions with which the Collaborations have been charged in December 2009 to produce new Decadal Plans by August 1, 2010. I have asked the Collaborations to provide interim reports on progress toward these Plans at the upcoming RHIC/AGS Program Advisory Committee meeting on June 21-22. Given the other constraints on national Nuclear Physics funding for the short-term future, it is critical for RHIC to develop clear and convincing plans for the second half of the coming decade, and beyond. I need all of your help in doing so.

Clearly, an important part of this future vision requires solidifying the science case, the technical feasibility and the user community for an eventual staged Electron-Ion Collider. I want to bring to your attention a very important 2-month long Workshop on EIC science to be held at the Institute for Nuclear Theory in Seattle in September-November 2010. It is important to build on this workshop to produce a coherent and compelling community-wide science white paper for the EIC in the year following the INT Workshop, in preparation for the next Nuclear Physics Long Range Plan. At BNL, in addition to work on the science case, we are trying to find ways to optimize facility construction costs by reusing as much as possible from the existing RHIC complex. This is work in progress, but again I want to invite increased user participation. Contact me or any of the following folks to find out how to get plugged in, if you aren’t already: Tom Ludlam, Elke Aschenauer, Thomas Ullrich, Raju Venugopalan, Vladimir Litvinenko for work at BNL, or Abhay Deshpande or Richard Milner for the EIC Collaboration.

Traffic Regulations On-Site at BNL

As one part of a multi-faceted laboratory response to serious safety incidents that occurred at BNL in 2008-9, we have stepped up enforcement of traffic regulations. All people who drive on site, including outside users and guests, are expected to know and obey the New York State traffic regulations that apply on-site as well as off-site in the BNL vicinity. Tickets for clear violations are being given with some regularity now, and the lab has adopted a clear, graded approach to disciplinary actions, depending on the severity and frequency of violations. These actions are described in this article. Please note that severe or repeated violations can result in suspension of onsite driving privileges. All RHIC/AGS user tickets are being copied to me so that I can help you to understand the seriousness with which the laboratory is approaching this.

The most important regulations to be cognizant of are the following:

• Obey speed limits – 30 mph or less
• Yield the right of way to pedestrians in crosswalks
• Wear your seatbelt (drivers and front-seat passengers)
• Use hands-free cell phones only (a New York State law)
• Stop at stop signs - no "rolling" stops
• Have a valid driver's license and car insurance

I have already seen quite a number of user tickets in the past month, mostly for rolling stops or cell phone usage while driving. The first offense of this type will result in a friendly reminder from me to not let this happen again. But repeated offenses will not lead to happy consequences, for you or for me. So please help us to make BNL a safer working environment.

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