RE: [Brahms-l] run progress -particular p/p-bar

Dear Flemming, sounds like great news. When we first put a k-/k+ vs pbar/p 
plot in an NA44 paper the reviewer said it was nonsense.
Michael

	-----Original Message----- 
	From: flemming videbaek [mailto:videbaek@rcf.rhic.bnl.gov] 
	Sent: Sat 3/27/2004 1:58 PM 
	To: brahms-l 
	Cc: 
	Subject: [Brahms-l] run progress -particular p/p-bar
	
	
	We have had some reasonable progress since Thursday in collecting data at 63 GeV (or 62.4).The data so far consists of
	~500k trigger 3 MRS for 40 deg, MRS was move to 45 last afternoon.
	at 3 deg we have 2M trigger 6 for B-pol (protons) an ~ 800k for A-Pol. So have well are we doing?
	 
	I analyzed run11344 and 11333 and got a rough statistics for particles with PID in Rich with a first
	non-opt matching, geometry etc... The setting is 1/2A,B accepting momenta in range ~8-20 GeV.
	I attach the mass plots for pos and neg. Recal that most protons (p-bar) are in fact below the rich threshold
	so most particle with mass=-1 are protons (apart from an effeciency corrections).
	The two runs have ~175k tr6 an 125 k.
	 
	Based on this the rough counts are
	 
	p        192 + 1200
	p-bar     5  + 180-60
	pi+      1801
	pi-        2907
	K+       718
	K-        333.
	 
	the statistics for protons is ~10* times this i.e. 14k which I guess is quite good.
	(What did we have in run-2 at 3 deg?? (peter)).
	Since the p-bar are very much reduced compared to p. it will be impossible to get a comparable 
	spectra for p-bars'. Since the 3 deg is essentially at the peak of the net-p istr, as evaluated from Hijing
	it seems to me best after the completion of the 3 deg B pol (same # triggers) to measure around y~2.1
	since 1/2 units change does not tell us so much.
	 
	regards
	Flemming
	 
	 
	Since I gave you the numbers let me also do the particlae ratios since otherwise someone else in the coll.
	will do so:
	 
	Normalise to N(tr)
	pi+/pi- ~ 0.85
	K+/K- ~ 0.33
	p-bar/p ~ 0.03-0.07 
	 
	(which is right on Becatinis curve if you wonder)
	 
	 
	----------------------------------------------------------------
	Flemming Videbaek
	Physics Department
	Brookhaven National Laboratory
	 
	e-mail: videbaek@bnl.gov
	phone: 631-344-4106

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