1 / 18

Measuring Strong Phases, Charm Mixing, and DCSD at CLEO-c

Measuring Strong Phases, Charm Mixing, and DCSD at CLEO-c. Mats Selen, University of Illinois HEP 2005, July 22, Lisboa, Portugal. CLEO Evolution. CLEO-II.V (9/fb). New RICH New Drift Chamber New silicon New Trigger & DAQ. CLEO-III (14/fb). Replace silicon with a wire vertex chamber.

gratia
Download Presentation

Measuring Strong Phases, Charm Mixing, and DCSD at CLEO-c

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Measuring Strong Phases, Charm Mixing, and DCSD at CLEO-c Mats Selen, University of IllinoisHEP 2005, July 22, Lisboa, Portugal

  2. CLEO Evolution CLEO-II.V (9/fb) New RICH New Drift Chamber New silicon New Trigger & DAQ CLEO-III (14/fb) Replace siliconwith a wire vertex chamber CLEO-c (281/pb)

  3. e+e-y(3770)DD K+ K- e- e+ p- p+ CLEO-c & D Tagging • Pure DD final state, no additional particles (ED = Ebeam). • Low particle multiplicity ~ 5-6 charged particles/event • Good coverage to reconstruct n in semileptonic decays • Pure JPC = 1- -initial state Tag one D meson in a selected tag mode. Study decays of other D, (signal D) Analysis Preview Targeted Analyses • Mixing (x2+y2):DD(K-l+n)2,(K-p+)2 • cosd:Double Tag Events: K-p+ vs CP± • Charm Mixing (y): Flavor Tag vs CP± • DCS: Wrong sign decays K-p+ vs K-l+n Comprehensive Analysis • Combined analysis to extract mixing parameters, DCS, strong phase plus charm hadronic branching fractions Charm Mixing, DCS, and cosd impact naïve interpretation of branching fraction analysis extension of Phys.Lett.B508:37-43,2001 hep-ph/0103110 Gronau/Grossman/Rosner & hep-ph/0207165 Atwood/Petrov See Asner & Sun, CLNS 05/1923

  4. Overview of fitting technique s(MBC) ~ 1.3 MeV, x2 withp0 s(DE) ~ 7—10 MeV, x2 withp0 Kinematics analogous to (4S)BB: identify D with Double tags 56 pb-1sample Single tags 56 pb-1sample 15120±180 377±20 D candidate mass (GeV) D candidate mass (GeV) Independent of L and cross section

  5. Single tags Double tags 3 D0 Modes 6 D+ Modes D0 2484±51 (combined) 56 pb-1sample D+ 1650±42 (combined) (log scale)! Global fit pioneered by Mark III NDD & Bi’s extracted from single and double tag yields with c2 minimization technique. See Gao’s talk on CLEOhadronic branching fractionsmeasurement.

  6. It’s a feature, not a problem… • The CLEO hadronic branching fraction analysis did not include CP specific final states since the quantum corrections to these are not consistent with the simple fitting approach used. • If we take these effects into account properly we will learn more ! • That’s the point of this talk.

  7. A simple way to understand what CP-tags can do for us: For the moment, ignore CP violation and mixing and write mass eigenstatesD1andD2as Consider the amplitudes for these mass eigenstates decaying toK-p+: A1 i.e. the CP even & CP odd rates to a specific final state will not be the same ! A2 In reality these are much shorter !

  8. The rate for the CP even D1 to decay to K-p+is given by: where Similarly, the rate for the CP odd D2 to decay to K-p+is given by: And to first order in r the asymmetry between CP even and CP odd taggedK-p+events is given by: Measuring rate differences yields information about d if we know r !!

  9. If we do the math correctly (i.e. we don’t ignore mixing etc) then wefind that the rates will depend on the mixing parameters x and y aswell as on r and z. Reminder By simultaneously measuring a collection of various rates we might expect to have enough constraints that all of the above can be (over) determined. We consider flavor tagged final states f and f, CP tagged final states S+ and S- And semileptonic final states l+ andl-.

  10. Big effect -show plots Biggest effects in CP ± 1final states What we learn from variousSingle and Double tag rates From DDthresholdrunning From D-sD+s(DDg,p)thresholdrunning Where

  11. K+K- KSp0 Double tag yield for (K+K-) vs (KSp0) = 40 events Naïve expectation (LeB)KK x (LeB)Ksp= 9.5 events We see the predicted factor of 4 from (CP-)(CP+) constructive interference

  12. CP tags are clearly very important… CP+ Note log scale D0p+p-

  13. Even our dirtiest CP+ tag is not so bad…

  14. Will use both 2 and 3-body CP- tags as well… Example: D0KSK+K- is mostly CP odd KSf

  15. Its also very important to do well with semileptonic modes… 281 pb-1 Inclusive semileptonic decays versus Kp tags.

  16. Explore the sensitivity of this method using Monte Carlo (Yield from 1 fb-1) (The number of CP+ tags will limit the statistical precision)

  17. (Yield from 1 fb-1) Better if world averagevalue for rKp is used.

  18. CombinedQC analysis Summary • In correlated D0D0 system, use time-integrated single and double tag yields to probe mixing and DCS parameters • “Targeted” analyses provide first measurement of cosd and improved limit on RM • “Comprehensive” analysis -Simultaneous fit for hadronic and semileptonic branching fractions, mixing and DCS parameters • Will be first direct measurement of cos(d) Projections of CLEO-c Sensitivity

More Related