Mixing and CPV in Charm Report from Charm WG5 (Warwick, Updated) D. Asner, Carleton U, I. Bigi, U. Notre Dame, F. Martinez Vidal, A. Oyanguren, IFIC, Universitat de Valencia-CSIC N. Neri, Universit`a di Pisa, B. Meadows, M. Sokoloff U. Cincinnati M. Blanke, Technische Universitaet Muenchen A. Palano, INFN, Bari Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

FCNC, Mixing and CPV in Charm Items Discussed: Interest in rare decays – D0+- CPV in Mixing Projected expectations Importance of aSL Running at charm threshold Time-Dependent Quantum Correlations (TDQC)? Simulation Wish List Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Brian Meadows, U. Cincinnati Interest in D0  +- Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

(Dominant in KL  +- - NOT necessarily so in D0 case) Search for D0  +- There is considerable theoretical interest in the FCNC decay D0  +- (see I. Bigi’s talk, Friday am) The SM estimates a lower limit BF > 4 x 10-13 Estimates would be improved by measurement of D0   Only estimate so far - BF[D0   ] < 1.5 x 10-5 [Recall that, for KL  +-, SM BF = 6.4 x 10-8 – right on the money!] Long-range mechanism (Dominant in KL  +- - NOT necessarily so in D0 case) Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

magnitude search window Interest in D0  +- R-parity SUSY could increase the decay rate by up to to 7 orders to BF~3.5x10-6 Current experimental limits are: Super B should be able to arrive at upper limits much better than this and also measure BF[D0  ] to better understand the SM limit. Opens a 7 orders of magnitude search window c u + - qk 12k 22k Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Brian Meadows, U. Cincinnati Interest in D0  +- Ikaros: “10-8 would be an interesting goal” At D threshold, the +- (or ) are “back-to-back” in transverse momentum and should present an excellent signal-to-noise ratio. [BESIII claim they will use 20 fb-1 to give them a 90% limit at 3 x 10-8 – apparently a mistake] http://arXiv.org/pdf/0801.1833 and Eur.Phys.J.C57:309-492,2008. Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Brian Meadows, U. Cincinnati D Mixing Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

D Mixing - What Can SuperB Do? Major Goals: Improve precision of x, y, |q/p|, Arg{q/p} Examine whether CPV originates from the mixing (p = q) or from decay (Arg{Af} = Arg{Af}) ? Possible Strategy: Compare (x,y) for D0 with (x,y) for D0 Compare different decay channels (is CPV in mixing or in decay?) Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Improve Precision – Projection of Y(4S) Measurements to SuperB (Alan Schwartz/David Asner – private communication) If central values persist: Will observe >> 5 effect !! x No-CPV point still allowed at 1σ NOW Assumptions: Central values are as reported at ICHEP2008 Scaling is done only for D0 K-+, D0Ks+- and  measurements. Systematic errors scale as 1/sqrt(N) The latter are mostly determined by data so this is approximately so. Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

If measurement lies on curve, CPV is ALL in MIXING Origin of CPV - aSL Wrong Sign (WS) lepton asymmetry measures CPV in mixing: No CPV See Talk by I. Bigi on Friday am If measurement lies on curve, CPV is ALL in MIXING aSL |q/p| Current Measurement ! Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Sensitivity to CPV in Mixing - aSL Can measure aSL at Y(4S) with D* tagging: Large backgrounds (much reduced using Dreco sample) We estimate 13,500 events / yr.  a = 1% per year. Measure it at (3770) Much cleaner reconstruction Can include WS hadrons since DCS is Bose-suppressed. Estimate 1,600 events per month  a = 1.4% in 4 mos. Obviously (3770) is more efficient, but not a “gotta have it”. Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Correlation with D0  Ks Asymmetry Measurement of S(Ks) and of aSL could eliminate or refine this model: See I. Bigi Friday a.m. (S) ~ 5 x10-4 (aSL) ~ 0.01 If CPV is in MIXING Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Running at Charm threshold Quantum Correlations (QC) Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Use Quantum-Correlations (QC) Running at y(3770) CLEO c were able to measure K-+ strong phase: from 281 pb-1 Including other D mixing results:  SuperB 300 fb-1: AND – the possibilities are that we can use OTHER channels with knowledge of strong phases Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Time-Integrated QC in Multi-body Channels For multi-body channels, we could measure relative phases “bin-by-bin” in their phase-space. Quantum correlations remove necessity for model describing phase space. Probably ONLY way to obtain a true PWA fit. X m-2 (GeV2/c4) m02 (GeV2/c4) X For higher multiplicities, we would measure “coherence” and a single strong phase. For 3-body final states this provides model-independent measurement of strong phase variation over the Dalitz plot - Useful for CKM measurement Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Time-dependent QC Decays – “Super D” ? The moving CMS means we could measure time-dependent (TD) strong phases resulting from D0 mixing. Leads to model-independent time-dependent phase space distribution. X m-2 (GeV2/c4) m02 (GeV2/c4) X Boost is ~same as for Y(4S) Is this possible or useful ? Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

“Double-Dalitz” Plot Fit: An example from CLEO c e+e-  (3770)  (Ks+-) (Ks+-) There are two Dalitz plots correlated in a time-dependent way: If you select CP-odd Ks0 in one, you see “no” Ks0 in the other. If you select RS K*-+ in one, you see only (opp. sign) RS K*+- in the other. EXCEPT: There will be a small signal arising from MIXING. This has a definite time-dependence, making it more identifiable above background. Backgrounds at (3770) are small ! CLEO data: - It works !! J. Napolitano http://indico.ihep.ac.cn/conferenceDisplay.py?confId=176 Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Brian Meadows, U. Cincinnati “Super D” ? The time-dependent “Double-Dalitz” analysis can be made on a wide variety of double-tagged events: (Ks+-) - (Ks+-) (Ks+-) – (Ks K+K-) (Ks+-) – (K-+0) (Ks+-) – (K-+) (Ks+-) – (K-K+) … etc. We need a simulation to learn how well this might work in face of reduced time-resolution wrt “Super B”.. Large samples. Highly constrained (model-dependent) Measure |q/p| and =Arg{q/p} direct CPV, … Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Simulation Wish List for TDR Sensitivity tests - Y(4S) simulations Resolution in M(D0),  M and (t) xD, yD, |q/p| using D*  D0+  Ks+- yCP and A from D0  K+K- and K-+ (xD2+yD2)/2 from D0  K-e+e T-odd moments analysis Simulations at (3770) Effectiveness of strong phase measurements at (3770) in mixing needs clarification Time resolution acheivable– at least two configurations (DGWG) D0  +- (with background) TDQC simulation study for 2009 document Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Brian Meadows, U. Cincinnati Progress Towards a TDR Impressive work has been done both at, and since, the Valencia workshop. http://www.slac.stanford.edu/spires/find/hep/www?irn=8013667 For progress towards a TDR, this is an excellent starting point: Some items not yet covered Measurement of fD , fDs form-factors, … Address experimental issues (tracking, end-cap PID) Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Brian Meadows, U. Cincinnati Backup Slides Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

“Super D” / “Super B” Comparison Advantages: D0’s are produced at (3770) at ~3 x the rate of B0’s at Y(4S) D0 decay rates are typically 100xB0 decay rates  So there are many more “double-tags” than in B’s from Y(4S) Example: CLEO have 420 double-tagged Ks+- events from 818 pb-1 that suggests “Super D” will have ~300K If KL+- could be added we would have 1.2M double-tagged events Handicaps wrt TDQC for B’s at Y(4S): D0’s also have little transverse momentum at y(3770) so we rely on the boost bg=p/m [~same as at Y(4S)] for time measurements BUT tD0 < 1/3tB0 so s ~ 30 mm is only about one D0 lifetime We only anticipate running for ~600 fb-1 (comparable to BaBar) Can make TD “Double-Dalitz” Plot fit with many correlations. Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Brian Meadows, U. Cincinnati Reminder from KL+- Standard model limit (“unitarity bound”) is Measured value is (6.86 § 0.37) x 10-9 Measured: 5.47 x 10-4 From QED: 1.20 x 10-5 x = 6.83 x 10-9 L.M. Sehgal, PR 183, 1511 (1969) BNL E791, Heinson et al, PRD 51, 985 (1995) Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Bigi, Blanke, Buras, Recksiegel Little Higgs with T-parity. NOT an MFV model arXiv:0904.1545 Monika Blanke S. Recksiegel A. Buras Ikaros Bigi … bets his beard that LHT models would lead to observable CPV in D decays! Later … is willing to grow a beard if CPV is not observed in D decays by 2017! Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

QC in Multi-body Channels For multi-body channels, this means we can measure strong phases “integrated over” the final state. The “coherence” measures to what extent this is useful. CLEO measurements (using external mixing information from elsewhere): We need to clarify how we include these measurements in mixing results from the Y(4S) Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

Brian Meadows, U. Cincinnati Ikaros Bigi … is willing to grow a beard if CPV is not observed in D decays by 2017! Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati