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Beyond SM Physics at a CLEO Charm Factory (some food for thought) Mats Selen, UIUC, May/5/2001

Beyond SM Physics at a CLEO Charm Factory (some food for thought) Mats Selen, UIUC, May/5/2001. Data Assumptions Tagging Rare decays D mixing CP violation Off The Wall. Data Assumptions. Assume we will accumulate 3 fb -1 on the ”(3770) 10 nb signal, 12 nb “other hadronic”:

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Beyond SM Physics at a CLEO Charm Factory (some food for thought) Mats Selen, UIUC, May/5/2001

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  1. Beyond SM Physics at a CLEO Charm Factory(some food for thought)Mats Selen, UIUC, May/5/2001 • Data Assumptions • Tagging • Rare decays • D mixing • CP violation • Off The Wall

  2. Data Assumptions • Assume we will accumulate 3 fb-1 on the ”(3770) • 10 nb signal, 12 nb “other hadronic”: • About 3x107 DD pairs • Assume BaBar & Belle will (each) have 400 fb-1 on the (4S) • 1.3 nb signal, 3 nb “other hadronic” • About 5x108 cc pairs each • Our competition will have ~17 times more charm on ~33 times more “other hadronic” background.

  3. Big Advantage: Tagging: • Two important benefits: • Flavor ID • Unambiguous Reconstruction e- • Suppose efficiency x BR (all tags) = 10% (more on this..) • Will have ~ 106 each tagged D0 and D+ per 1 fb-1 • Limits of order 10-6 possible from 3 fb-1 data (still pretty good) e+ e- e+ p- K+

  4. p0 e- e+ e- e+ p- K+ Rare Decays Example Study: D0 p0e+e- • In 32290 generic D0 decays: • 1098 D0 K-p+tags (eB=3.4%) • 1543 D0 K-p+ p0tags (eB=4.8%) (DC=1 Weak Neutral Current) Tag using: D0 K-p+ (B = 3.83%) D0 K-p+p0 (B = 13.9%) With just these two modes, eBtag=8.2% Working Group: What is the tradeoff: efficiency vs cleanliness

  5. …if we don’t properly exclude tagged tracks Ability to get rid of this stuff is a keyadvantage! Tagged events epeexeBtag= 1.5% Notag ~ 500 evt

  6. Suppose epee.eBtag= 1.5 % Suppose we have 3 fb-1 (~1.5x107 D0D0 pairs) Suppose we see 0 events 90% CL upper limit is ~5 x 10-6 About a factor of 100 improvement over PDG in most cases. Most modes studied were in the 10-6 10-5 range Its hard to imagine BaBar/Belle would not be in the same ballpark,although based on simple scaling I think we have the edge inclean modes where they are background limited. See Excel Table See Bruce Yabsley’s talk in beyond SM working group

  7. For example… CLEO-c B-fact Simple spreadsheetanalysis tool available for working group.

  8. CLEO-II Presently:90% CL Upper Limits < 2.4x10-4 For both modes CLEO-II wg rg Some interesting examples: • 1) B(D0 gg)- SM small: ~10-8 (Singer et. al. hep-ph/0104236) • - good hunting for physics beyond SM. • - no present limit, CLEO-c sensitivity ~ 10-6 • 2) G(D0 rg) / G(D0 wg)(Fajfer et. al. hep-ph/0006054) • - Individual BR’s small: ~10-6 • Long distance effects cancel in ratio. • - Ratio should be ~1 (30% deviation means new physics) See Will Johns’talk in beyond SM working group

  9. In hadronic decays: K- D0 D0 D0 D0 MIX K+ y = DG/2G (real) D0 DCS CF K-p+ W W D0 x = DM/G (virtual) d = dR–dW (important to measure) r = A /A Mixing Phenomenology:

  10. D0-D0 Mixing: At the Y(4S) Con • Ultimately limited by Backgrounds & Systematics CLEO K*ln analysis CLEO K3p analysis Pro • Lots of data • Time evolution handle

  11. 0.1 y 0 -0.1 0 0.2 0.1 x Experimental Situation (May/2001)

  12. D0-D0 Mixing: At the ”(3770) Pro • Tagging ! • - Flavor known • - All tracks accounted for • Quantum Correlations - opens up new avenues of search: K+ p- e- e+ p- K+ Con • No Time evolution handle: D0’s produced ~at rest • Can’t measure DG directly using lifetime differences.

  13. The D0 and D0 are produced coherently in a JPC = 1-- state. • Time integrated decay rate to final state f1,f2: K+ p- e- e+ (assumes CP conserved) p- K+ See hep-ph/0103110Gronau, Grossman & Rosner (and also working group tomorrow) Looks slightlydifferent for C +initial states likeDDg

  14. K- K- p+ p+ p+ p- K- K+ Useful for probing x & y Ratio of Rates: Interesting Case 1:

  15. KS K+ K+ KS r0 K- r0 K- p- p- p- p- CP- eigenstate CP- eigenstate K+ K+ K+ K+ = 2 r cosd Useful for probing r & d CP+ eigenstate Asymmetry = Interesting Case 2: CP+ eigenstate There are several other interesting cases to study: See Jon Rosner’s & Alexey Petrof’s talks in beyond SM working group

  16. u p+ d c s K0 D0 d K*- u u d p- CF: D0 K*-p+ Fit for these in Dalitzplot… Mix or DCS: D0 K*+p- Another Example:D0K0p+p-Dalitz Plot Analysis to extract mixing parameters: …along with other good stuff: other K*’s, K2, r, w, f0, f2…

  17. In CLEO II.V: Sensitivity to x & ywill be about 3% See “wrong sign”decays at 5s level. See David Asner’s talk in beyond SM working group

  18. u u D0 p-r+ D0 r-p+ p+ r+ d d c c d d p- r- D0 D0 u u u u D0 p0r0 p0 c c d s d u u u u u r0 Also accessible from the D0 Interference ! Yet another Example:D0p+p-p0Dalitz Plot Analysis: D0 K0p0 K0 d D0 D0 u p0

  19. MD*-MD r+ r- KS r0 CLEO-II.V D0p+p-p0Dalitz Plot Analysis (preliminary): At CLEO-c we will have 5-10x more events with no background

  20. D f Compare Df to Df D f Direct CP violation: Need two paths frominitial D to final state f.

  21. Find: Direct CP violation: Good News: We know large strong phase differences (d1- d2) are not uncommon in charm decays! This is an important ingredient. Good/Bad News: Expect small weak phase differences in Standard Model. SM ACP may be as big as 10-3for some decay modes Definitely a hunting ground for new physics.

  22. Observing this is evidence of CP CP(f1 f2) = CP(f1) CP(f2) (-1)l = CP- K+ + - (since l = 1) K- e- e+ p- p+ At the ”(3770) e+e- ”  D0D0 JPC = 1-- i.e. CP+ Suppose both D0’s decay to CP eigestates f1 and f2: These can NOT have the same CP :

  23. CP violation in Dalitz Plots: Example Search: D0 K-p+p0

  24. Fit D0 and D0 Dalitz Plots separately and look for asymmetries: D0 - D0 “Difference” Plot Find ACP= 0.0310.086 Better sensitivity to new physics expected in CS modes. Some are under investigation: D0 K-K+p0 and D0 p-p+p0 This will be easier to do at a charm factory than at Y(4S) due to backgrounds. See Daniele Pedrini’stalk in beyond SM working group Q: Are structural differences that integrate to zero interesting?

  25. General Observation High statistics background free DalitzPlot analyses will be a great place to lookfor interesting physics at CLEO-c Not only “Beyond SM”, also QCD etc..

  26. The size R of the extra dimension is given bywhere MP is the 4-dimensional Planck scale. Rn ~ MP2MS-(n+2) g photon q J/ Look for q h,f graviton or dilaton (undetected) If time, end with something just for fun:Sensitivity to Large Extra Dimensions: From Bijnens & Maul hep-ph/0006042 If there are n large extra dimensions the decay J/g + (h,f) may be sensitive to the compactification scale MS:

  27. If BR( J/g + (h,f) ) < 10-5 we can set these lower boundson MS (as a function of n). Predicted photon spectrum

  28. There is lots of interesting physics “Beyond the Standard Model” that will be explored with CLEO-c Find out more at tomorrows working group:

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