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/5/1 ata Assumptions Tagging Rare decays mixing CP violation Off The Wall CLEO-c Workshop 1

2 ata Assumptions Assume we will accumulate 3 fb -1 on the ψ (377) 1 nb signal, 1 nb other hadronic : About 3x1 7 pairs Assume BaBar & Belle will (each) have 4 fb -1 on the Υ(4S) 1.3 nb signal, 3 nb other hadronic About 5x1 8 cc pairs each Our competition will have ~17 times more charm on ~33 times more other hadronic background. CLEO-c Workshop

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

4 π e - Rare ecays e + e + π e Example Study: π e + e ( C=1 Weak Neutral Current) K + Tag using: In 39 generic decays: K π + (B = 3.83%) 198 K π + tags (εb=3.4%) K π + π (B = 13.9%) 1543 K π + π tags (εb=4.8%) With just these two modes, εb tag =8.% Working Group: What is the tradeoff: efficiency vs cleanliness CLEO-c Workshop 4

5 Tagged events ε πee x εb tag = 1.5% if we don t properly exclude tagged tracks ~ 5 evt No tag Ability to get rid of this stuff is a key advantage! CLEO-c Workshop 5

6 Suppose ε πee. εb tag = 1.5 % Suppose we have 3 fb -1 (~1.5x1 7 pairs) Suppose we see events 9% CL upper limit is ~5 x 1-6 Most modes studied were in the range About a factor of 1 improvement over PG in most cases. Its hard to imagine BaBar/Belle would not be in the same ballpark, although based on simple scaling I think we have the edge in clean modes where they are background limited. See Excel Table See Bruce Yabsley s talk in beyond SM working group CLEO-c Workshop 6

7 CLEO-c B-fact Simple spreadsheet analysis tool available for working group. For example CLEO-c Workshop 7

8 Some interesting examples: 1) B( γγ)- SM small: ~1-8 (Singer et. al. hep-ph/1436) - good hunting for physics beyond SM. - no present limit, CLEO-c sensitivity ~ 1-6 ) Γ( ργ)/ Γ( ωγ) (Fajfer et. al. hep-ph/654) - Individual BR s small: ~1-6 - Long distance effects cancel in ratio. - Ratio should be ~1 (3% deviation means new physics) CLEO-II ργ CLEO-II ωγ Presently: 9% CL Upper Limits <.4x1-4 For both modes See Will Johns talk in beyond SM working group CLEO-c Workshop 8

9 Mixing Phenomenology: K K + y = Γ/Γ (real) In hadronic decays: MIX CS CF W W x = Μ/Γ (virtual) K π + Ae iδ K π + R K π + Ae δ = δ R δ W (important to measure) iδ W r = A /A CLEO-c Workshop 9

10 - Mixing: At the Y(4S) Pro Lots of data Time evolution handle Con Ultimately limited by Backgrounds & Systematics CLEO K3π analysis CLEO K*lν analysis CLEO-c Workshop 1

11 Experimental Situation (May/1).1 y x. CLEO-c Workshop 11

12 - Mixing: At the ψ (377) Con No Time evolution handle: s produced ~at rest Pro Tagging! - Flavor known - All tracks accounted for Quantum Correlations - opens up new avenues of search: K + Can t measure Γ directly using lifetime differences. π e + K + π e CLEO-c Workshop 1

13 π e + K + e See hep-ph/1311 Gronau, Grossman & Rosner (and also working group tomorrow) K + π The and are produced coherently in a J PC = 1 1 ψ = [ ( pˆ ) ( pˆ ) ( pˆ ) ( pˆ )] INITIAL Time integrated decay rate to final state f 1,f : Γ( f1, f) = A + + B 1 y 1+ x 1 y 1+ x state. Looks slightly different for C + initial states like γ A = B = f 1 f f1 f f 1 f f1 f (assumes CP conserved) CLEO-c Workshop 13

14 Interesting Case 1: π + K - Ratio of Rates: K - K - π + π + K + π Γ( K Γ( K π π + +, K, K + π π + ) ) = 1 ( x + y ) + smaller terms Useful for probing x & y CLEO-c Workshop 14

15 Interesting Case : K + CP+ eigenstate Κ K S CP- eigenstate ρ Asymmetry = K + CP+ eigenstate Κ K + π K + K S CP- eigenstate ρ π K + π K + π = r cos δ Useful for probing r & δ There are several other interesting cases to study: See Jon Rosner s & Alexey Petrof s talks in beyond SM working group CLEO-c Workshop 15

16 Another Example: K π + π alitz Plot Analysis to extract mixing parameters: c u u d s d d u π + K π K CF: K π + Mix or CS: K + π Fit for these in alitz plot along with other good stuff: other K* s, K, ρ, ω, f, f CLEO-c Workshop 16

17 In CLEO II.V: Sensitivity to x & y will be about 3% See wrong sign decays at 5σ level. See avid Asner s talk in beyond SM working group CLEO-c Workshop 17

18 Yet another Example: π + π π alitz Plot Analysis: π ρ + c u u d d u ρ + π ρ π + c u u d d u π + ρ π ρ c d π c d u ρ u u u Κ π s d u u Κ π Also accessible from the Interference! CLEO-c Workshop 18

19 CLEO-II.V π + π π alitz Plot Analysis (preliminary): M * -M ρ + ρ K S ρ At CLEO-c we will have 5-1x more events with no background CLEO-c Workshop 19

20 irect CP violation: Need two paths from initial to final state f. A e 1 iδ 1 f A e iδ Compare f to f A f A f = = A e 1 * 1 i A e δ 1 + i δ + A A 1 * e e iδ iδ A e * 1 iδ 1 f A e * iδ CLEO-c Workshop

21 irect CP violation: Find: A CP = A A f f + A A f f = A 1 + Im( A A * 1 A )sin( δ + Re( A * 1 A 1 δ ) )cos( δ 1 δ ) Good News: We know large strong phase differences (δ 1 δ ) are not uncommon in charm decays! This is an important ingredient. Good/Bad News: Expect small weak phase differences in Standard Model. SM A CP may be as big as 1-3 for some decay modes efinitely a hunting ground for new physics. CLEO-c Workshop 1

22 At the ψ (377) K + Κ e + e e + e ψ J PC = 1 i.e. CP+ π + π Suppose both s decay to CP eigestates f 1 and f : These can NOT have the same CP : CP(f 1 f ) = CP(f 1 ) CP(f ) (-1) l = CP + (since l = 1) Observing this is evidence of CP CLEO-c Workshop

23 CP violation in alitz Plots: Example Search: K π + π CLEO-c Workshop 3

24 Fit and alitz Plots separately and look for asymmetries: A CP = M M M + M dp - ifference Plot Find A CP =.31 ±.86 Q: Are structural differences that integrate to zero interesting? Better sensitivity to new physics expected in CS modes. Some are under investigation: K Κ + π and π π + π This will be easier to do at a charm factory than at Y(4S) due to backgrounds. See aniele Pedrini s talk in beyond SM working group CLEO-c Workshop 4

25 General Observation High statistics background free alitz Plot analyses will be a great place to look for interesting physics at CLEO-c Not only Beyond SM, also QC etc.. CLEO-c Workshop 5

26 If time, end with something just for fun: Sensitivity to Large Extra imensions: From Bijnens & Maul hep-ph/64 If there are n large extra dimensions the decay J/ψ γ + (h,φ) may be sensitive to the compactification scale M S : The size R of the extra dimension is given by where M P is the 4-dimensional Planck scale. R n ~ M P M S -(n+) Look for J/ψ q q γ h,φ photon graviton or dilaton (undetected) CLEO-c Workshop 6

27 If BR( J/ψ γ+ (h,φ) ) < 1-5 we can set these lower bounds on M S (as a function of n). Predicted photon spectrum CLEO-c Workshop 7

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: CLEO-c Workshop 8