Charged Kaon Mass in UMC

			Takeshi K. Komatsubara (KEK)
			last update: 2003-Apr-01

 *This txt is based on my post to e949 general on 2003-Apr-01. 


  A student asked me a question: 
	Why the K+ mass in UMC, 493.!!667!!, 
	is different from the mass on PPB, 493.!!677!! ?

% cd /e949/src/umc/ 
% fgrep -ni 493 *.F
alldat.F:469:     2     493.667,   497.67,   497.67, 938.2796, 939.5731 , 0. / 
ncint3.F:326:      DATA RMASS/0.,.511,105.659,134.963,139.5673,493.667,
wmug.F:21:      DATA EM/.493667/
wmugnr.F:61:        DATA EM,R/.493667,.10566/
wmugnr.F:102:   DATA MKAON,MMUON /493.667,105.659/
wmugnr.F:136:      DATA MKAON,MMUON /493.667,105.659/
wmugnr.F:176:      DATA MKAON,MMUON /493.667,105.659/
wmugnr.F:216:        DATA EM,R/.493667,.105659/
wmugnr.F:258:   DATA MKAON,MMUON /493.667,105.659/
wtau.F:11:      DATA E,PIN/493.667, 5.133725E-05/            ! Mk, 1/MPi+**2 


 Contrary to our natural guess, this is not a typo. 
 PDG's K+ mass in 80's, when the UMC was under development, 
 was in reality 493.667 MeV, 
 and has been changed accrding to subsequent measurements. 
 (A table of the history is attached at the end of this Email.)

  I will NOT change the K+ mass in UMC from now; 
 if you want to use the correct mass,
 please overwrite 493.667 in UMC source codes to 493.677 by yourself.
 (Also remind that KOFIA also uses 493.667 for the K+ mass.)

kumc/alldat.F:433:     2     493.667,   497.67,   497.67, 938.2796, 939.5731 , 0. / 
unp/montdmp.F:38:     2     493.667,   497.67,   497.67, 938.2796, 939.5731 , 0. /



 History of the charged kaon mass
 ---------------------------------

	PDG 84	493.667 +- 0.015 from fit
	PDG 86	493.667 +- 0.014 from fit

					Gall	88	493.636+-0.011

	PDG 88	493.646 +- 0.009 
	PDG 90	493.646 +- 0.009 
	PDG 92	493.646 +- 0.009 

					DENISOV	91	493.696+-0.007
					 There is a disagreement between the
					 two most recent and precise results.
					 Both of them are measurements of 
					 X-ray energies from kaonic atoms.
					 See "Note on the Charged Kaon Mass"
					 in the full listings 
					 (1994 by T.G. Trippe, LBNL).

	PDG 94	493.677 +- 0.016 OUR FIT Error includes scale factor of 2.8
	PDG 96	493.677 +- 0.016 OUR FIT Error includes scale factor of 2.8
	PDG 98	493.677 +- 0.016 OUR FIT Error includes scale factor of 2.8
	PDG 00	493.677 +- 0.016 OUR FIT Error includes scale factor of 2.8
	PDG 02	493.677 +- 0.016 OUR FIT Error includes scale factor of 2.8

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