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White Paper  TDR (?)

White Paper  TDR (?). Introductory Comments B. Meadows For the charm team. Charm Team (Since Elba, 2011). Milind Purohit and Nicola Neri have agreed to join in the organization of the charm working group in its next phase  TDR . Welcome to both – there is much to do!.

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White Paper  TDR (?)

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  1. White Paper  TDR (?) Introductory Comments B. Meadows For the charm team Brian Meadows, U. Cincinnati

  2. Charm Team (Since Elba, 2011) Milind Purohit and Nicola Neri have agreed to join in the organization of the charm working group in its next phase  TDR. Welcome to both – there is much to do!

  3. Charm Topics at QMUL Meeting White paper (WP) –> TDR Run at Y(4S) D0 mixing – a FastSim study Run at (3770) Magnetic field ? Time-dependence – what could we measure ? TD Decay correlations Other charm thresholds ?

  4. The “White Paper” (WP) (arXiv:1008.1541 [hep-ex] ) Charm section

  5. Rolf’s talk Mike, Gianluca, Adrian, Fernando talks Elaborate in thistalk WP – Known Short Falls (Need to be done) • Few Fastsim simulations exist • Mixing in D0Ksp+p- at Y(4S) • Preliminary feasibility study of D0m+m- at Ã(3770) • Studies at Y(4S): Mixing • Use of other modes to find x and y are all estimated from Babar analyses • Do not include measurement of |q/p|, arg {q/p} from D0-D0 asymmetries Rare decays • Realistic understanding reach for D0 m+m-, D0 g gD0 h+l+ l-, D0 r0 l+ l- • Running at (3770) ~DD threshold • QC phase measurements - how to include them in 4S mixing measurements • Better estimates for s(ASL) • Rare decays such as D0 m+m-, D0 g g • How to use time-dependent decay correlations • Use of other thresholds (Ds, c ?)

  6. Other Studies • Various physics items added since the WP • D0 -> invisible , g + invisible, “X0 ” + invisible at BOTH Y(4S) and threshold. • T-correlations in D0 -> l+ l-h+h- and D0 -> l+l-l+l- • IFF we ever find any such events, of course !! • CPT Violation • Charm baryons • Run at Ds threshold too – f(Ds) and semi-leptonic decays (Vcs) • Time-dependent quantum correlated decay studies • Various double-tagged combinations

  7. Some Computing Needs Set up of FastSim for Running at threshold We now have .DEC files from CLEO-c for runs at various thresholds Also have code from Werner Sun for including Time-Integrated quantum correlations using an accept/reject technique. ( ~ 50%) Both Milind and Mike Sokoloff have offered to provide code that will include time-dependent quantum correlations. Machine backgrounds – we depend on background simulation folks An interface from charm group would help. Recent Estimates for INFN support of SuperB@CNAF Space for 2 x 109 generic FastSim MC at 3770. NOTE that  (cc) ~ 30 (6.4) nb x 500 ev/fb  15 (3.2) x 109 events  This is a concession on our actual needs. Space for 1 x 109 signal of various types. (Pure guess).

  8. Threshold Running Scenario • Only run envisaged so far is a 500 fb-1 exposure at (3770) • About 600 x CLEO-c and (50-100) x BES III • Just above DD threshold • At one-tenth nominal luminosity, Super B can complete this in a few months • Set up and tuning of final focus may take another few months  Perhaps a year altogether – maybe less? • Since the WP was published, new possibilities exist • The boost could be raised from =0.23 to 0.1 (P. Raimundo) • Maybe other thresholds or even larger runs can be made. • When/if to do this needs more discussion.

  9. Other DD Thresholds? Thresholds in increasing order (MeV/c2): Channel ECM (MeV/c2) D0D0 3730 D+D- 3739 D0D*0 3872 D+D*- 3880 Ds+Ds- 3937 D*0D*0 4014 D*+D*- 4020 Ds+Ds*- 4081 Ds*+Ds*- 4220 cc 4572 Running at (3770) provides a clean sample of D's. We expect: 1.8 x 109 D0D0 1.4 x 109 D+D- 1.2 x 109+- 500 fb-1 How about ECM=4010 for cleanDsDs sample ? • CLEO-c also ran at4170 MeV/c2 to study Ds’s • PRO’s • Cross-section for DsDs* peaks. • Below Ds*Ds* threshold. • CON’s • Does not maximize yields of DsDs • Introduces some difficulty in sorting out the Ds events from the D and D*'s. Should we consider this too ?

  10. CLEO-c Ds Scan arXiv:hep-ex/0606016v2 At each of green points, select events with various D0, D+ or Ds tags For each, plot Mbc vs. E where and E0 = beam energy ED, PD are energy and momentum of D decay products. CLEO-c Ds Scan PDGCross sections

  11. CLEO-c Ds Scan arXiv:hep-ex/0606016v2 Some Cabbibo suppressed decays lead to D0 modes Signals are fitted to give various 2-body cross-sections. Ds++ tag at Eee=4170 MeV/c2

  12. Envisage a 100 fb-1 run at 4020 where  ~ 0.3 nb Produce ~30 x 106DsDs events CLEO-c ran 0.6 fb-1 at 4170 where  ~ 0.9 nb Produce ~2 x 105DsDs* (mostly Ds*) events Two-body Ds Cross-SectionsarXiv:hep-ex/0606016v2 CLEO-c ran here  Vcs ??

  13. CLEO-c with 0.65 fb-1at 4170 reconstructed ~ 10K events: Measured semi-leptonic BF’s for Ds: SuperB with 100 fb-1at 4020 shouldreconstruct ~ 1.5Mevents: Semi-leptonic Ds Decays and Vcs Might expect  Vcs to ~1% ?? Phys.Rev. D81 (2010) 052007 • Major systematic uncertainties: • Normalization signal • Extrapolation of lepton momentum • Used Ds  tag • Normalization signal was • recoil MM that included DsAND Ds* • Major systematic uncertainties: • Normalization signal • Extrapolation of lepton momentum • Normalization signal would then be • recoil MM that included ONLY Ds

  14. Some Computing Needs Set up Running at threshold We have now obtained .DEC files from CLEO-c for running at various thresholds We also have code from Werner Sun for including Time-Integrated quantum correlations using an accept/reject technique. ( ~ 50%) Both Milind and Mike Sokoloff have offered to provide code that will include time-dependent quantum correlations. Machine backgrounds – we are depending on background simulation folks here E-mail list for this group (please subscribe): https://lists.infn.it/sympa/info/superb-physics-charm Wiki (SuperB physics portal): http://mailman.fe.infn.it/superbwiki/index.php/Physicsxortal

  15. Extra Slides Brian Meadows, U. Cincinnati

  16. General Reasons for a (3770) Run • It is possible (likely?) that an unusual effect – perhaps due to NP – will be found in the charm sector from (4S) running • A true confirmation in the entirely different charm scenario at (3770) will trump a simple repeat performance with more luminosity at (4S) • A 500 fb-1 run will improve both our own, and also LHCb’s CKM  measurement by a factor ~ 3. • Decays of (3770)  D0D0 produce coherent (C=-1) pairs of D0’s. Quantum correlations in their subsequent decays allow measurements of strong phases • Required for improved measurement of CKM  • Also required for D0 mixing studies

  17. General Reasons for a (3770) Run • A record exists of several cases where CLEO-c, sometimes with just 281 pb-1 of their 818 pb-1 sample at (3770), has successfully competed with BaBar’s ~0.5 ab-1 and Belle’s ~1 ab-1 at (4S). Examples: • Measurement of decay constants – fD and fDs • Studies of leptonic and semi-leptonic decays, • Measurements of absolute hadronic branching fractions • Other runs for CLEO-c at other CM masses have produced useful and novel results for Ds as well as D decays from (3770). •  Is a program at (4S) complete without the “service” of one at (3770), etc.?

  18. CLEO-c Hadronic Charm Decays at (3770) Single Tags Only E ~ 0 in signal E sidebands in yellow

  19. Example of D0 K-e+e decay from CLEO-c’s 818 pb-1 exposure at (3770). Quantity plotted is U = Emiss – c Pmiss (Note background level ~0) Semi-Leptonic Decays

  20. Time-dependent QC Decays – “Super D” ? The moving CMS means we could measure time-dependent (TD) strong phases resulting from D0 mixing. 20 m-2 (GeV2/c4) m02 (GeV2/c4) Samples are large. E.g. Ks+- (on both sides) will have about 500K events. X X Boost is ~same as for Y(4S) but D0 ~ 0.4B0 Re-cap from Warwick summary 2008 Is this possible or useful ? What else can we learn from this ? Brian Meadows, U. Cincinnati Super B, Elba, Italy, 5/30-6/05/2010

  21. “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, … Re-cap from Warwick summary 2008 Brian Meadows, U. Cincinnati

  22. DD Threshold Measurements Data from DD threshold provide measurement of strong phases such as K and <K¼0 >. They also provide measured values of  in Dalitz plot bins This can be used (with a model for the values forr) to significantly reduce uncertainties in the Dalitz plot model used in the golden channel analyses. As a basis for projection, we take results from CLEO-c: N. Lowrey et al, PRD80, 031105 (2009), 0903.4853 We assume that new data from threshold will reduce the uncertainties in model uncertainty: BES III – ~factor 3 improvement in model uncertainty Super B 500 fb-1DD threshold run – ~factor 10 improvement.

  23. Two improvements in mixing precision come from threshold data: Value of Strong Phase Measurements • Dalitz plot model uncertainty shrinks • Information on overall strong phase is added Uncertainty inxDimproves more than that of yD

  24. Summary of CPV Sensitivity from Mixing 24 Brian Meadows, U. Cincinnati Super B, Elba, Italy, 5/30-6/05/2010

  25. Precision of aSL Uncertainty from a signal S over background B is Background “spoils” asymmetry measurements.

  26. Measurement of aSL – Needs (3770) Data! Decays to wrong-sign (WS) leptons proceed through mixing Rate is very small RM=(x2+y2)/2x10-4~ 5x 10-5 and not yet observed: 0.82 fb-1 492 fb-1 344 fb-1 Another D In event Right-sign (RS) Decays D0K-e+e+ c.c. RM< 6x10-4 RM< 13x10-4 (3770): D0tagged (4S): D0 tagged by D*+D0 + efully reconstructed enot reconstructed Include Hadronic decays* Background limits WS data  (asl) for 500 fb-1 ~ 0.20  (asl) for 75 ab-1 ~ 0.80  (asl) for 75 ab-1 ~ 0.20 *At (3770). We need CLEO-c data to refine our knowledge of backgrounds we can expect.

  27. aSL from (3770) Data(Needs evaluation from simulation) Two un-ambiguous possibilities. One ambiguous possibility. Could resolve ambiguity using difference in time-dependence of mixing (t2e-t) vs. direct DCS decay (e-t). 27  (3770)  (3770) K+e-e K+- K+e-e K+- Can we do this anyway? Bose statistics requires that one D0 had to mix  (3770) K+- (coherent) K+e-e D0K+-5 x more likely to beDCSthanD0->K+e-eis from mixing Brian Meadows, U. Cincinnati Super B, Elba, Italy, 5/30-6/05/2010

  28. Rare Decays D0 gg , D0 “invisible”and D0 +-, etc.Other Thresholds 28 Brian Meadows, U. Cincinnati Super B, Elba, Italy, 5/30-6/05/2010

  29. 29 Ikaros Bigi … willing to grow a beard if CPV is not observed in D decays by 2017! Get well soon, Ikaros !! Brian Meadows, U. Cincinnati Super B, Elba, Italy, 5/30-6/05/2010

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