From pxs@mppmu.mpg.de Thu May 31 19:51:21 2012 Date: Thu, 31 May 2012 19:51:11 +0200 (CEST) From: Peter Seyboth To: Grebieszkow Katarzyna , Laszlo Andras , Blume Christoph , Kollegger Thorsten Cc: Hoehne Claudia , Stroebele Herbert , Gazdzicki Marek , Beck Hans , Book Julian Subject: Re: editorial committee for pi,K centrality dependence paper Dear Herbert and Marek, Triggered by comments of the Cern referee I have some questions concerning the statistical model. We know that 4pi yields of strange particles in central Pb+Pb are suppressed with respect to a grand canonical ensemble. This suppression is even stronger in lighter systems. There are several strategies to fix up the simplest grand canonical model. (1) for p+p use the canonical ensemble. If I am not mistaken, that is still not enough and one has to introduce something like a Wroblewski factor in addition. (2) introduce gamma_s to describe the suppression of the strangeness sector in A+A with ratios of strange particle yields unaffected (3) subdivide the total volume into subvolumes for A+A. Here I am not sure what is done next. Canonical ensemble fit in each subvolume without gamma_s ? Is that enough to get the suppression for the sum of yields from all subvolumes ? Then there is, of course, the core-corona model which does not use the statistical model at all. This model does not try to fit the suppression, it kind of interpolates between Pb+Pb central collisions and p+p collisions to describe the change of suppression with system size. In summary, I am missing a mention of gamma_s in the discussion of the statistical model on page 4 and as well as more explicit description of the assumptions of ref.[20]. Could perhaps Marek and Claudia enlighten me. Best regards, Peter