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Update of at large angle (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284 C.Bini, B.Di Micco KLOE Memo 285 (1) Results of the fit (2) Forward-Backward asymmetry (3) Upper limit on + -

Update of ppg at large angle (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

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Update of ppg at large angle (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284 C.Bini, B.Di Micco KLOE Memo 285 (1) Results of the fit (2) Forward-Backward asymmetry (3) Upper limit on h  p + p -. (1) Results of the fit. N(Q) = K  [ - PowerPoint PPT Presentation

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Page 1: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

Update of at large angle (LNF 20/02/2004)

See: C.Bini, S.Ventura KLOE Memo 284C.Bini, B.Di Micco KLOE Memo 285

(1) Results of the fit(2) Forward-Backward asymmetry(3) Upper limit on +-

Page 2: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

(1) Results of the fit

N(Q) = K [FISR(Q, M, , , ) + FFSR(Q) + Ff0(Q, gfKK, R, mf0) FINT(Q) +F(Q) + F3(Q) ]

K = fcoll(Q) (Q) L bfcoll(Q) = correction for collinear radiation (EVA)(Q) = efficiencyL = integrated luminosity (349 pb-1)b = bin size (1.2 MeV)

Results stability checked vs.:Bin size (1.2, 2.4, 6.0, 12.0 MeV)First point (280 to 660 MeV)Last point (996 to 1015 MeV)

Page 3: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

background: , - Achasov param.

- PDG abs. normalisation

- No interference (??)

3 background (survivingthe cuts):

- MC based abs. normalisation

Page 4: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

- interference no interference + interference

Page 5: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

Fit- Fit0 Fit+

2 / 481 755 597 750

g2fKK/4(GeV2) 1.52 0.13 0.98 0.07 0.16 0.28 0.02

R 1.69 0.15 7.83 0.32 0.50 6.9 0.6

Mf0 (MeV) 934 4 980.6 0.4 0.6 992.1 0.6

M (MeV) 774.3 0.2 773.6 0.2 0.8 773.4 0.2

(MeV) 145.3 0.5 144.6 0.3 1.2 145.4 0.3

( x 10-2) 0.169 0.005 0.176 0.005 0.008 0.191 0.015

-0.129 0.005 -0.115 0.002 0.004

-0.094 0.007

< 0.2 <0.16 <0.11

<0.06 0.31 0.08 0.30 0.06

(f0 +-) (MeV) 230 30.6 9.8

BR (6.6 0.6) x 10-5

Table with fit results:compare the 3 hypotheses;for fit0 hyp. stability estimate (second error)

Page 6: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

Attempt to fit “forcing” f0 00 KLOE parameters:

Fit no Fit

g2fKK/4(GeV2) 1.29 2.79

R 3.22 4.00

Mf0 (MeV) 962 973Fit02 = 3700

Fit-2 = 1313

Page 7: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

f0 +- after subtraction (red) vs. f0 00 “raw” spectrum (blue)

2 possible explanations:(1) spectrum has “another contribution”(2) has “another interference scheme”

Page 8: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

(2) Forward-backward asymmetry+- system: odd terms (green) and even terms (brown)A(ISR) C-odd A(FSR) C-evenA(f0) C-even

|A(tot)|2 = |A(ISR)|2 + |A(FSR)|2 + |A(f0)|2 + 2Re[A(ISR) A(FSR)]+ 2Re[A(ISR) A(f0)]+ 2Re[A(FSR) A(f0)]

Asymmetry in + - angle (depending on the cuts)

Page 9: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

The integrated FB-asymmetry is (two definitions):

)90()90(

)90()90(1 oo

oo

NN

NN

)90()90()90()90(

2 oo

oo

NNNN

Page 10: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

Comparison with MC: Eva + Geanfi reconstruction:

(red) data(triangles) MC gener.(open circles) MC recon.

data-MC discrepancy below 700 MeVClear f0 effectData > MC between 700 and 900 MeV

Page 11: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

f0 signal in M() spectrum and in FB asymmetry

Page 12: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

(3) Upper limit for +-

Expected signal: Gaussian = 547.3 MeV

= 1.33 MeV

Ns = -22 24 Ns < 21.1 (90%C.L.)

N = 1.43 107

(from 30 counting)

BR( -) < 8.9 10-6

Comments:(1) Factor 37 improvement respect to previous limit(2) The negative fluctuation helps !

Page 13: Update of  ppg  at large angle   (LNF 20/02/2004) See: C.Bini, S.Ventura KLOE Memo 284

Conclusions:Perspectives for publication and presentation at conferences:

(1) The fit of the M() spectrum is in “final shape”;(2) The FB-asymmetry reinforces the f0 signal

BUT does not add any further insight:needs “theoretical support”.(3) The upper limit is also in “final shape”: discussion on the way to extract the limit are welcome.