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Search for X(3872)  p 0 p 0 J/ y

Properties of X(3872). Search for X(3872)  p 0 p 0 J/ y. S.K. Choi & S.L. Olsen. Motivation. For C=+1, X(3872)  p + p - J/ y is all via r p + p - expect no p 0 p 0 since rp 0 p 0 is forbidden For C=-1, X(3872)  p + p - J/ y has I=0 p + p -

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Search for X(3872)  p 0 p 0 J/ y

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  1. Properties of X(3872) Search for X(3872)p0p0J/y S.K. Choi & S.L. Olsen

  2. Motivation • For C=+1, X(3872)p+p- J/y is all via rp+p- • expect no p0p0since rp0p0is forbidden • For C=-1, X(3872)p+p- J/y has I=0 p+p- • expect Xp0p0 J/y ½ p+p-J/y (by ispin) • seeing or not seeing p0p0can determine C

  3. Selection • Standard J/y l+l- cuts • p3 (p0) >0.15 GeV; c2(p0)<6 (both p0s) • |Mbc-5.28|<0.009 or -0.06<DE<0.03 GeV • M(p0p0) > M(p0p0J/y) –M(J/y) –0.2 GeV • Mult. entr: Min( c2=(Mgg-Mp0)2/s2 + DE2/s2)

  4. M(pp) cut p+p-J/y p0p0J/y M(p0p0) M(p+p-) M(p+p-l+l-)-M(l+l-) M(p+p-l+l-)-M(l+l-) (apply same p momentum & M(pp) cuts to p+p- sample)

  5. y’p0p0J/y signal Mbc Nev = 55.4 ±10.2 events

  6. y’p+p-J/y signal Mbc Nev = 742 ± 28 events

  7. X(3872)p+p-J/y signal Mbc Nev = 62.6 ±8.3 events

  8. X(3872)p0p0J/y signal? No signal!! Mbc Nev = 0.2 ±2.6 events (< 4.4 evts 90% CL)

  9. Br(Xp0p0J/y) limit determination Br(Xp0p0J/y) Br(Xp+p-J/y) = ~1±0.1 Nev(Xp0p0J/y) Nev(y’p0p0J/y) Nev(Xp+p-J/y) Nev(y’ p+p-J/y) e(y’p0p0J/y) e(Xp0p0J/y) e(y’ p+p-J/y) e(Xp+p-J/y) Br(y’p0p0J/y) Br(y’p+p-J/y)   reduce by 1s Br(y’p0p0J/y) Br(y’p+p-J/y)  < 1.3

  10. p0p0J/y summary • no sign of Xp0p0J/y • but sensitivity is still not • enough to distinguish • between C = +1 or -1

  11. Other items for BC-0439shown at previous BGMs & in public • Limit on Xgcc2 • Angular dist compared with 1+- expectations • Limit on Xg J/y

  12. Look for X(3872)gcc2 No signal !! Mbc Mgcc2 G(Xgcc2) G(Xp+p-J/y) <1.1 Contrary to expectations for charmonium D states

  13. Fit to 1+- c2=75/9 |cosqJ/y| 1+- (hc’) is ruled out!

  14. M(g J/y) BKcc1; cc1g J/y X(3872) ? Br(Xg J/y) Br(Xp+p-J/y) <0.4

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