C+C pions rapidity fits with temperature formula

y = C * T^3 * ( (m0/T)^2 + 2*m0/(T*cosh(y*y_cm)) + 2/(cosh(y*y_cm)**2) ) *exp(-m0*cosh(y*y_cm)/T)
where y = (y_lab-y_cm)/y_cm
with 2 parameters C and T.
Constants: m0=139.57, y_cm=0.677 for 1 GeV and 0.907 for 2 GeV
(e.g. S Sadovski PhD page 78 eq 7.17)

First check of the formula on the "ideal" PLUTO distribution for 1 GeV with T=58 MeV and A_2=0 (and blast=0):

• PLUTO right: fit within measured range, left: fit in full range - both work well, see parameter p1 == T
  

Now fit of PLUTO distribution for 1 GeV with T=58 MeV and anisotropy A_2=0.34:

• PLUTO right: fit within measured range, left: fit in full range: in full range the fitted slope changed by 16 MeV, chi^2 high. In measured range the

T slope cannot be recovered.

Now exp. data fit (together with fit of UrQMD data within measured range and full range) for CC at 1 GeV and 2 GeV. Results are summarized below in the table:

• C+C 1 AGeV:
  

• C+C 2 AGeV:
  

C+C 1 AGeV

exp.

UrQMD

UrQMD

exp. range

full range fit

T

chi2/NDF

T

chi2/NDF

T

chi2/NDF

pi+

119+-24

2.7/20

1530+-2040

4256/20

172.4+-0.5

16600/39

pi-

114+-22

4.6/20

1634+-2057

6072/20

184.0+-0.6

23400/39

C+C 2 AGeV

exp.

UrQMD

UrQMD

exp. range

full range fit

T

chi2/NDF

T

chi2/NDF

T

chi2/NDF

pi+

2900+-111

31/13

2600+-2050

7280/13

315.4+-1.4

49200/39

pi-

2677+-53

26/13

2393+-5

6449/13

310.0+-1.3

48300/39

-- PavelTlusty - 28 May 2008