From: Jens Jørgen Gaardhøje (gardhoje@nbi.dk)
Date: Thu Feb 27 2003 - 09:32:30 EST
Dear Friends I have just heard a series of lectures on spin physics. I have learned quite a bit and have received some inspiration. It appears that there are a number of quite improtant and interesting issues that we could (easily) address in BRAHMS. Perhaps these are known to you, but are certainly new to me. In particular it seems that the pion transverse asymmetry in p-pol + p is dramatic ( almost a factor of 2 in ct rate ratio between left and right). at forward rapidities. It also appears that there are significant asymmetries at 90 deg (in the pi-plus channel, but not in the pi-minus channel). These effects are apparently poorly understood in QCD. hand waving arguments require the scattering to involve quarks from the Dirac sea with inverse polarization. It seems obvious to me that we should pursue this. Experimentally it seems to me that we need the following: -a tag on each event with the bunch number, so that we may afterwards know the polarization (measured by others) of each bunch ( sequence of 2 up and 2 down....). I am not aware whether this information is currently in our event stream - and if not what it takes to put it there. cheers JJ ____________________________________________________________ Jens Jørgen Gaardhøje, Assoc. Prof., Dr. Sc. Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen, Denmark. Tlf: (+45) 35 32 53 09, secr. (+45) 35 32 52 09, Fax: (+45) 35 32 50 16. UNESCO Natl. Comm., secr. (+45) 33 92 52 16. Email: gardhoje@nbi.dk. ____________________________________________________________
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