Mixing and CPV in Charm Report from Charm

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Mixing and CPV in Charm Report from Charm WG 5 (Warwick, Updated) D. Asner,

Mixing and CPV in Charm Report from Charm WG 5 (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: q Interest in rare decays –

FCNC, Mixing and CPV in Charm Items Discussed: q Interest in rare decays – D q CPV in Mixing q § Projected expectations § Importance of a. SL Running at charm threshold § q 0 + - Time-Dependent Quantum Correlations (TDQC)? Simulation Wish List Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati 2

3 Interest in D Super B, Perugia, Italy, 6/18/2009 0 + Brian Meadows, U.

3 Interest in D Super B, Perugia, Italy, 6/18/2009 0 + Brian Meadows, U. Cincinnati

4 Search for D 0 + q q There is considerable theoretical interest in

4 Search for D 0 + q q There is considerable theoretical interest in the FCNC decay D 0 + (see I. Bigi’s talk, Friday am) The SM estimates a lower limit BF > 4 x 10 -13 Long-range mechanism q (Dominant in K L + - - NOT necessarily so in D 0 case) Estimates would be improved by measurement of § Only estimate so far - BF[D [Recall that, for K L 0 D 0 ] < 1. 5 x 10 -5 + -, SM BF = 6. 4 x 10 -8 – right on the money!] Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

5 Interest in D 0 + q R-parity SUSY could increase the decay rate

5 Interest in D 0 + q R-parity SUSY could increase the decay rate by up to 7 orders to BF~3. 5 x 10 -6 c 12 k + qk u q q 22 k to Opens a 7 orders of magnitude search window - Current experimental limits are: Super B should be able to arrive at upper limits much better than this and also measure BF[D 0 ] to better understand the SM limit. Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

6 Interest in D 0 + q Ikaros : “ 10 -8 would be

6 Interest in D 0 + q 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 a mistake] -1 to give them a 90% limit at 3 x 10 -8 http: //ar. Xiv. org/pdf/0801. 1833 and Eur. Phys. J. C 57: 309 -492, 2008. Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati – apparently

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

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

8 D Mixing - What Can Super. B Do? Major Goals: q q Improve

8 D Mixing - What Can Super. B Do? Major Goals: q q Improve precision of x, y, | q/p |, Arg{q/p } Examine whether CPV originates from the mixing (p = q ) or from decay ( Arg{ A f} = Arg{A f}) ? Possible Strategy: q q Compare (x, y) for D 0 with (x, y) for D 0 Compare different decay channels (is mixing or in decay? ) Super B, Perugia, Italy, 6/18/2009 CPV in Brian Meadows, U. Cincinnati

Improve Precision – Projection of Y(4 S) Measurements to Super. B No-CPV point still

Improve Precision – Projection of Y(4 S) Measurements to Super. B No-CPV point still allowed at 1σ If central values persist: Will observe >> 5 effect !! NOW x x (Alan Schwartz/David Asner – private communication) Assumptions: • Central values are as reported at ICHEP 2008 • Scaling is done only for D 0 K- +, D 0 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 9

10 Origin of CPV - a. SL q Wrong Sign (WS) lepton asymmetry measures

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

11 Sensitivity to CPV in Mixing q Can measure a. SL at Y(4 S)

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

12 Correlation with D 0 K s Asymmetry (S) ~ 5 x 10 -4

12 Correlation with D 0 K s Asymmetry (S) ~ 5 x 10 -4 (a. SL) ~ 0. 01 See I. Bigi Friday a. m. If CPV is in MIXING Measurement of S(K s ) and of a. SL could eliminate or refine this model: Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

13 Running at Charm threshold Quantum Correlations (QC) Super B, Perugia, Italy, 6/18/2009 Brian

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

14 Use Quantum-Correlations (QC) q Running at (3770) CLEO c were able to measure

14 Use Quantum-Correlations (QC) q Running at (3770) CLEO c were able to measure K - + strong phase: from 281 pb q -1 Including other D mixing results: Super. B 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

15 Time-Integrated QC in Multi-body Channels • For multi-body channels, we could measure relative

15 Time-Integrated QC in Multi-body Channels • For multi-body channels, we could measure relative phases “bin-by-bin” in their phase-space. X Quantum correlations remove necessity for model describing phase space. For higher multiplicities, we would measure “coherence” and a single strong phase. m-2 (Ge. V 2/c 4) Probably ONLY way to obtain a true PWA fit. X m 02 (Ge. V 2/c 4) For 3 -body final states this provides modelindependent measurement of strong phase variation over the Dalitz plot Useful for CKM measurement Brian Meadows, U. Cincinnati Super B, Perugia, -Italy, 6/18/2009

Time-dependent QC Decays – “Super D” ? • The moving CMS means we could

Time-dependent QC Decays – “Super D” ? • The moving CMS means we could measure timedependent (TD) strong phases resulting from D 0 mixing. X Boost is ~same as for Y(4 S) m-2 (Ge. V 2/c 4) Leads to modelindependent timedependent phase space distribution. X m 02 (Ge. V 2/c 4) Is this possible or useful ? Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati 16

“Double- Dalitz ” Plot Fit: An example from CLEO c e+e- (3770) (Ks +

“Double- Dalitz ” Plot Fit: An example from CLEO c e+e- (3770) (Ks + -) q There are two Dalitz plots correlated in a time-dependent way: § § If you select CP-odd K s 0 in one, you see “no” K s 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/conference. Display. py? conf Id =176 Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati 17

18 “Super D” ? q q The time-dependent “Double- Dalitz ” analysis can be

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

19 Simulation Wish List for TDR q Sensitivity tests - Y(4 S) simulations §

19 Simulation Wish List for TDR q Sensitivity tests - Y(4 S) simulations § § § q Resolution in M(D 0), M and (t) x D, y D, |q/p | using D * D 0 + K s + y CP and A from D 0 K +K - and K - + (x D 2+y D 2)/2 from D 0 K -e+ e T-odd moments analysis for 2009 document Simulations at (3770) § § § Effectiveness of strong phase measurements at (3770) in mixing needs clarification Time resolution acheivable – at least two configurations (DGWG) D 0 + - (with background) TDQC simulation study (x D 2+y D 2)/2 from D 0 K -e+ e Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

20 Progress Towards a TDR q Impressive work has been done both at, and

20 Progress Towards a TDR q 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: q Some items not yet covered § § Measurement of f D , f Ds form-factors, … Address experimental issues (tracking, end-cap PID) Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

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

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

22 “Super D” / “Super B” Comparison q Advantages: § D 0’s are produced

22 “Super D” / “Super B” Comparison q Advantages: § D 0’s are produced at (3770) at ~3 x the rate of B 0’s at Y(4 S) § D 0 decay rates are typically 100 x. B 0 decay rates So there are many more “double-tags” than in B’s from Y(4 S) § Example: CLEO have 420 double-tagged K s + - events from 818 pb that suggests “Super D” will have ~300 K § If K L + - could be added we would have q -1 1. 2 M double-tagged events Handicaps wrt TDQC for B’s at Y(4 S): § D 0’s also have little transverse momentum at (3770) so we rely on the boost b =p/m [~same as at Y(4 S)] for time measurements § BUT D 0 < 1/3 B 0 so ~ 30 m is only about one D 0 lifetime § We only anticipate running for ~600 fb -1 (comparable to Ba. Bar ) q Can make TD “Double- Dalitz ” Plot fit with many correlations. Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

23 Reminder from K L + q Standard model limit (“ unitarity bound”) is

23 Reminder from K L + q Standard model limit (“ unitarity bound”) is 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) q Measured value is (6. 86 § 0. 37) x 10 -9 BNL E 791, Heinson et al, PRD 51, 985 (1995) Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

24 Bigi , Blanke , Buras, Recksiegel Little Higgs with T-parity. NOT an MFV

24 Bigi , Blanke , Buras, Recksiegel Little Higgs with T-parity. NOT an MFV model ar. Xiv: 0904. 1545 S. Recksiegel Monika Blanke A. Buras … bets his beard that LHT models would lead to observable CPV in D decays! Super B, Perugia, Italy, 6/18/2009 Ikaros Bigi … is willing to grow a beard if CPV is not observed in D decays by 2017! Later Brian Meadows, U. Cincinnati

25 QC in Multi-body Channels q For multi-body channels, this means we can measure

25 QC in Multi-body Channels q 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. q CLEO measurements (using external mixing information from elsewhere): q We need to clarify how we include these measurements in mixing results from the Y(4 S) Super B, Perugia, Italy, 6/18/2009 Brian Meadows, U. Cincinnati

26 Ikaros Bigi … is willing to grow a beard if CPV is not

26 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