Despite the arguments by particular Phenix and Brahms, T.Kirk has decided (as is his right as Assosicate . LabDirector) to bypass the majority of opinions as well as recommendations from the PAC and allocate the last 24 hours of the run to 22 GeV. I still believe believe this is a bad decision, but the is no more to do at this point , but to acknowledge "it is good to be from MIT" We should later make a decision if if will just stop running at 8 am Sunday (Nov 25) or attempts to look at the beam at 22 GeV. ------------------------------------------------------ Flemming Videbaek Physics Department Brookhaven National Laboratory tlf: 631-344-4106 fax 631-344-1334 e-mail: videbaek@bnl.gov Subject: Decision on Running at 22 GeV This Year > . November 14, 2001; 5:00 PM > > Colleagues: > > After hearing all the comments at today's Experimenter's > Meeting, I have reached a decision on the proposed 24-hour > run at 22 GeV proposed by PHOBOS. I will supply my decision > here and then supply some comments that weighed in my > thinking. > > Decision: RHIC will devote the last 24 hours of the last > day (Sunday, November 25, 6:00 AM to Monday, November 26, > 6:00 AM) of the Au x Au run to running at 22 GeV as proposed > by PHOBOS and supported from the theory side by Dmitri > Kharzeev. By my best understanding, if there is success > in achieving luminosity at 22 GeV, STAR will expect to > take data but has some reservations about their ability > to sort out systematic error in the trigger; BRAHMS and > PHENIX do not expect to record useful amounts of data at > this energy. Accordingly, the accelerator should establish > collisions first at PHOBOS, then at STAR and then (if > requested by the experiments) at PHENIX and BRAHMS. > > Comments: > - There are two considerations here: 1) will the 22 GeV run > achieve useful physics data? 2) will the loss of one day > of runninng impose unacceptable losses on the 200 GeV > Au x Au run? It is my belief that the answer to the first > question is "yes" for PHOBOS; "yes, but" for STAR; and > "no" for PHENIX and BRAHMS. On the second question, I > observe the impact of missing one day of running for the > most data-short experiment, PHENIX psi/J is about 5-10% > according to my own projection (taken from Tony Frawley's > slide). We all hope the availability will somehow be > better from now until the end and all are committed to > this goal, but the expectation is not for a lot of > improvement in the frequency of hardware failures. > - This kind of question is especially hard to decide given > the anticipated long delay before we can reasonably get > back to Au x Au running at 200 GeV. Whether or not we > do more of this will again be considered by the experiments > for FY 2003 running and by the PAC. I expect a move > towards d x Au running at full energy next year. > - I considered extending the Au x Au running by one day but > this is in serious conflict with our other goal of getting > 5 weeks of p x p running. This latter goal has higher > priority and I will pull out all stops to make this happen. > > I must now send this out. I hope people will accept that > this decision was not an easy one. > > Sincerely, Tom Kirk >
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