1. Marina Artuso 1 Beyond the Standard Model: the clue from charm Marina Artuso, Syracuse University  D o D o, D o  K -  + K-K- K+K+ ++  K-K- K+K+

2. Marina Artuso 2 Experimental strategies considered u Mixing u Comparison between hadronic and lepton tagged modes from C=  1 D o D o pairs u Study of “right-sign” leptons versus “wrong sign leptons” u CP violation u Direct CP violation in D o and D + u Indirect CP violation in D o decays u CP violation measurements exploiting the quantum coherence of the D o D o pair u Rare and forbidden decays u Decay constants revisited

3. Marina Artuso 3 A glimpse into the world of new physics? u Mixing u CP violation }  Exploit quantum coherence of initial state at the   and  D 0 D 0 u Study interference effects induced by strong phases (Dalitz plot analyses)

4. Marina Artuso 4 Experimental Situation (May/2001) D 0 D 0 mixing

5. Marina Artuso 5 D 0 D 0  K +   K +   & r D No r DCSD component because of quantum statistics Sensitivity can be enhanced by adding other modes (such as K (*)+ l  (*)  l ). Standard Model predictions quite uncertain. We will not span the full range of Standard Model predictions, but we may see “new physics driven”, possibly distinguishing x from y  UL(sqrt(r D ))  0.01 @95%CL

6. Marina Artuso 6 A COMPREHENSIVE MAPPING OF MIXING PARAMETERS - 1 Final state  (C=-1)  (C=+1) K-+K-+K-+K-+ A 4 (x 2 +y 2 )/24A 4 (r 2 +ry’+3/8(x 2 +y 2 ) K-+K+-K-+K+- A 4 (1-2r 2 cos2  - 1/2(x 2 -y 2 )) A 4 (1+2r 2 cos2  -+4ry- 3/2(x 2 -y 2 )) K-+SK-+S A 2 A S    cos  A 2 A S    y  Comparison of CPeven and odd allows determination of cos  Linear in y hep-ph/0103110 Gronau, Grossman & Rosner

7. Marina Artuso 7 CP eigenstates CP(+1) eigenstates ChannelB.F.(x10 3 )  3fb -1  #(3fb -1  D 0 D 0 ) K-K+K-K+ 4.1110,0009,400  1.636,0003,000  15.054,2004,600 CP(-1) eigenstates ss 3.561,6005,300 ss 6.098,4008,400 ss 10.6176,00015,000 ss 10.0141,00012,000 ss 4.339,1003,300

8. Marina Artuso 8 Phase  determination from C=-1 sample We sum over all the CP eigenstates of a given sign to obtain =  (K -  + S + ) We can use MM technique to increase statistics Expected accuracy in cos  is  0.05

9. Marina Artuso 9 Lepton tagged samples Final state  (C=-1)  (C=+1) K -  + l - A 2 A 2 (1-1/2(x 2 -y 2 ))A 2 A 2 (1+2ry-3/2(x 2 -y 2 )) K -  + l + A 2 A 2 (r 2 -1/2(x 2 +y 2 )) A 2 A 2 (1+2ry+3/2(x 2 +y 2 )) S  l + A 2 A S    y 2  A 2 A S    y+3y 2 )  2l -2l - l-l- l+l+ l-l- l+l+ ~ l+l+ l+l+ CP even – CP odd asymmetries linear in y

10. Marina Artuso 10 CP Violation experimental search techniques u Direct CP violation in D  decays u CP violation in the decay of a D o D o pair u CP violation in final state distributions (D  VV) u Order of magnitude expected in Standard Model  10 -3 u New physics can enhance CP asymmetries + in this scenario they can emerge in Cabibbo allowed modes

11. Marina Artuso 11 CP violation in charm decays u Present experimental data:  FOCUS A cp (D +  K - K +  + )=-0.001  0.022  0.015,  FOCUS result A cp (K + K - )=-0.001  0.022  0.015  CLEO A cp (D 0  K - K + )=+0.05  0.0218  0.0084 u CLEO-C error  0.01 with 3 fb -1 with a variety of techniques. In some measurements b- factories are very competitive

12. Marina Artuso 12 CP asymmetries from flavor tagged decays Necessary ingredients: Flavor tag (lepton/kaon) CP eigenstate Obtain a cp, for example:

13. Marina Artuso 13  A cp with flavor tagged CP eigenstates CP eigenstate Flavor tagged sample AA K+K-K+K- 10,200 0.01 Ks0Ks0 10,4000.01 KsKs 3,5000.02

14. Marina Artuso 14  A cp sensitivities u Self tagging modes (D +, D s ) O (10 -3 ) 0.009 D +  + K *0 O (10 -3 ) 0.007 D++D++ O (10 -3 ) 0.008 D++D++ SM predictions  A cp ( L int =3 fb -1 ) Mode

15. Marina Artuso 15  D o D o  f + f + or f - f -  (f + =K + K -,  +  -,K s  A single background free event  CP violation CP eigenstate 1CP eigenstate 2# for 100% CPV K+K-K+K- K+K-K+K- 174 K+K-K+K- Ksp0Ksp0 171 K+K-K+K- r0p0r0p0 183 Ksp0Ksp0 Ksp0Ksp0 136 We can increase statistics x3-4 using MM technique discussed before

16. Marina Artuso 16 CP violation studies in the Dalitz Plot High statistics background free Dalitz Plot analyses may turn out to be the most sensitive probes of CP violation in D decays Not only “Beyond SM”, also QCD etc..

17. Marina Artuso 17 Rare and forbidden decays u Some D decays are forbidden: Standard Model expectations are several order of magnitude below any experimental reach  laboratory for “Standard Model background free” searches for new physics  the charm threshold region has the advantage of high efficiency and low background both for charged particle final states and final states including  and  o.  Sensitivities to branching fractions O (10 -6 ) expected

18. Marina Artuso 18 Leptonic Decays: D  l + Introduction: Pseudoscalar decay constants Q and q can annihilate probability is  to wave function overlap Example  - : In general for all pseudoscalars: _

19. Marina Artuso 19 f D and new physics We can probe violation of m-t universality Effect can be a few % with new physics 2HDM prediction

20. Marina Artuso 20 Summary on decay constant reach Decay mode Decay constant ½B/B½B/B ½   Vcq / Vcq  f D q /f D q D +  fDfD 1.9% 0.6% 1.1%2.3% D s  fDsfDs 1.4% 1.0% 0.1%1.7% D s  fDsfDs 1.2% 1.0% 0.1%1.6%

21. Marina Artuso 21 Conclusions u CLEO-c can probe for physics beyond the Standard model with 4 different strategies u Mixing studies u CP violation studies u Rare decays u Precision decay constant measurements u Phenomenology is very rich, some measurements unique (quantum coherence of initial state) u Search for signatures of physics beyond the Standard Model in charm is very important and our studies will be complemented by other experiments (BaBar, BELLE, BTeV…)