Status of the interference paper ee pp continuum

Status of the interference paper • e+e- p+p- (continuum) background • bug found and fixed • kinematic fit

e+e- p+p- background from CMD-2 (PLB 595, 2004) s (e+e- p+p- ) @1040 Me. V = (2. 01± 0. 33) nb Expexcted # events in the KLKS p+p- p+pdata sample= 328 pb-1 2 nb e to be evaluated from MC 2

MC private production of e+e- p+p- • 2970000 events produced • 2622 tagged from the identication of KS p+p • 128 selected events surviving the analysis cuts to select KL p+p- 4. 3 10 -5 rejection power Expected number of events : 328 pb-1 2 nb 4. 3 10 -5 = 28 3

Counting of 4 pi bkg • Cut for the data sample e + e - K SK L p + p - : • Cut to study the bkg e +e - p +p - : to reject KSKL p +p - 4

Counting of 4 pi bkg from the sides c 2 variable for the PID 4 pi bkg 4 pi signal c 2 FIT/dof = 138/122 DATA Km 3 c 2 # 4 p bkg in the sideband : 39 11 extrapolation in the signal region KSKL p+p- : 27 8 5

Background subtraction DATA FIT signal+bkg pppp bkg MC pppp bkg to be scaled for 4. 7 Dt/t. S Dt /t. S 6

Results c 2/dof = 17. 3/22 DATA FIT signal+bkg pppp bkg c 2/dof = 17. 3/22 In the memo: Dt /t. S 7

KS lifetime bug in MC: wrong value of s (not from the database), shifted by 0. 5 Me. V DATA MC sdata = (1. 119 0. 021) ts s. MC = (1. 1627 0. 0040) ts t. KS/ ts bug fixed: s from the database DATA MC t. KS/ ts 8

Extraction of ts and resolution : cut on Dt > 10 ts to take KL away DATA sdata = (1. 152 0. 020) ts ts = (0. 9030 0. 0056) 10 -10 s. MC = (1. 1807 0. 0036) ts ts PDG = (0. 8935 0. 0008) 10 -10 1. 4 s agreement DATA MC t. KS/ ts DATA FIT c 2/dof = 252/150 t. KS/ ts 9

Kinematic fit • Input variables: decay length of KS, decay length of KL, f position • probability distribution pj taken from MC as a function of dj = xj. MC-xjrec projected onto proper unit vectors (e 3 almost orthogonal to K line of flight, e 2 almost parallel to K line of flight, e 1 orthogonal to the p’s plane ) to minimize correlations Referee’s question: what about correlations? 10

9 input variables 36 correlation coefficients the biggest r = -0. 17 between d. L 2 and d. S 2, r = 0. 13 between d. L 1 and d. L 3 11

The other correlation coefficients are below 3% d. L 1 d. L 3 0. 132 d. L 3 0. 008 d. L 2 d. L 1 0. 020 d. S 1 d. S 2 0. 018 d. S 1 d. S 3 -0. 023 d. S 2 d. S 3 -0. 026 d. L 3 d. S 3 -0. 004 d. L 3 d. S 2 0. 009 d. L 3 d. S 1 -0. 005 d. L 2 d. S 1 -0. 001 d. L 2 d. S 2 -0. 172 d. L 2 d. S 3 -0. 017 12

d. L 1 d. S 3 d. L 1 d. S 2 d. L 1 d. S 1 df 1 d. S 2 d. S 3 df 2 df 3 df 1 0. 0006 0. 008 0. 004 -0. 00003 0. 008 -0. 031 -0. 009 -0. 004 0. 004 -0. 015 13

d. L 1 d. L 2 df 1 df 2 df 3 df 1 d. L 2 df 2 d. L 2 df 3 d. L 3 df 1 df 2 df 1 df 3 df 2 df 3 0. 004 0. 010 -0. 001 -0. 007 0. 011 0. 001 -0. 002 -0. 0007 0. 004 -0. 003 14

Conclusion all referee comments addressed and more. . . Draft paper/note in preparation 15