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arXiv:0810.3666v1 [hep-ex] 20 Oct 2008

34thInternational Conference on High Energy Physics, Philadelphia, 2008

Improving the precision of γ/φ3via CLEO-c Measurements

P. Naik (for the CLEO collaboration)

University of Bristol, Bristol BS8 1TL, UK

Quantum correlations in ψ(3770) → D0¯D0provide unique access to information about strong phase differences.

Precision determination of the CKM phase γ/φ3 via B → DK decays depends upon constraints on charm mixing

amplitudes, measurements of doubly-Cabibbo suppressed amplitudes and relative phases, and studies of correlated

charmed meson decays tagged by flavor or CP eigenstates. CP-tagged D0→ K−π+π−π+decays and CP-tagged

D0→ K0

the Cornell Electron Storage Ring (CESR) at√s = 3.77 GeV, we perform analyses of these decays. We describe the

techniques used to measure the D-decay parameters, and the CLEO-c impact on measurements of γ/φ3.

Sπ+π−Dalitz plots are only available at CLEO-c. Using the 818 pb−1CLEO-c data sample produced by

1. INTRODUCTION

1.1. Measuring the CKM Phase γ

Precision measurements of the weak phases that compose the unitarity triangle, α, β and γ, allow us to test the

internal consistency of the Cabbibo-Kaboyashi-Maskawa (CKM) model and search for signatures of New Physics.

The CKM phase γ is only constrained by direct measurements to (67+32

determining the CKM phase γ exploit the interference within B±→ DK±decays, where the neutral D meson is a

D0or¯D0. The most straightforward of these strategies considers two-body final states of the D meson, but additional

information can be gained from strategies that consider multi-body final states. The parameters associated with the

specific final states needed for these analyses can be extracted from correlations within CLEO-c [2] ψ(3770) data.

−25)◦[1]. The most promising methods of

1.2. Determination of the CKM phase γ from B±→ DK±

The interference between decays of the type B±→ DK±provide a theoretically clean method for extracting the

CKM phase γ when the D0and¯D0mesons decay to a common final state, fD. For example, we may write the ratio

of the amplitudes between the suppressed amplitude and the dominant amplitude as:

A(B−→¯D0K−)

A(B−→ D0K−)= rBei(δB−γ), (1)

and we may write a similar ratio for B+→ DK+. The ratio of these amplitudes is a function of the ratio of the

amplitudes’ absolute magnitudes (rB), a CP invariant strong phase difference (δB), and the CKM weak phase γ.

Due to color and CKM suppression, rB∼ 0.1 [1]; therefore, the interference is generally small. A variety of strategies

exist, however, that attempt to resolve this and maximize the achievable sensitivity to γ.

2. The ADS Formalism and D → K−π+

Atwood, Dunietz and Soni (ADS)[3] have suggested considering D decays to non-CP eigenstates as a way of

maximizing sensitivity to γ. Final states such as K−π+, which may arise from either a Cabibbo favored D0decay or

a doubly Cabibbo suppressed¯D0decay, can lead to large interference effects and hence provide particular sensitivity

to γ. This can be observed by considering the rates for the two possible B−processes:

Γ(B−→ (K−π+)DK−) ∝ 1 + (rBrKπ

Γ(B−→ (K+π−)DK−) ∝ r2

D)2+ 2rBrKπ

2+ 2rBrKπ

D cos?δB− δKπ

D cos?δB+ δKπ

D

− γ?,

− γ?,

(2)

B+ (rKπ

D)

D

(3)

1

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34thInternational Conference on High Energy Physics, Philadelphia, 2008

i ci (K0

Sπ+π−vs. CP-Tags) ci (K0

Sπ+π−vs. K0

Sπ+π−) si (K0

Sπ+π−vs. K0

Sπ+π−)

1

2

3

4

5

6

7

8

0.706 ± 0.069 ± 0.028

0.586 ± 0.126 ± 0.037

0.041 ± 0.120 ± 0.043

-0.510 ± 0.178 ± 0.074

-0.949 ± 0.063 ± 0.029

-0.807 ± 0.108 ± 0.039

0.085 ± 0.154 ± 0.046

0.339 ± 0.082 ± 0.024

0.779 ± 0.087 ± 0.062

0.874 ± 0.120 ± 0.113

0.003 ± 0.166 ± 0.152

-0.165 ± 0.323 ± 0.152

-0.929 ± 0.058 ± 0.044

-0.472 ± 0.196 ± 0.099

0.459 ± 0.204 ± 0.170

0.526 ± 0.109 ± 0.114

0.380 ± 0.179 ± 0.085

0.137 ± 0.260 ± 0.084

0.749 ± 0.145 ± 0.053

0.490 ± 0.400 ± 0.093

0.141 ± 0.268 ± 0.085

-0.679 ± 0.203 ± 0.059

-0.558 ± 0.367 ± 0.106

-0.376 ± 0.169 ± 0.060

Table I: Preliminary CLEO results for ci and si with respect to a particular type of tag.

Acknowledgments

The author wishes to thank David Asner, Neville Harnew, Qing He, Jim Libby, Andrew Powell, Jonas Rademacker,

Ed Thorndike, and Guy Wilkinson for their contributions and guidance in preparing these results.

References

[1] J. Charles et al., CKMfitter Group, Eur. Phys. J. C41, 1 (2005);

Updated results and plots at http://ckmfitter.in2p3.fr.

[2] Y. Kubota et al., Nucl. Instrum. Meth. Phys. Res., Sect. A 320, 66 (1992);

D. Peterson et al., Nucl. Instrum. Meth. Phys. Res., Sect. A 478, 142 (2002).

[3] D. Atwood, I. Dunietz and A. Soni, Phys. Rev. Lett. 78, 3257 (1997).

[4] E.Barberio

etal., arXiv:0808.1297

http://www.slac.stanford.edu/xorg/hfag.

[5] J.L. Rosner et al., Phys. Rev. Lett. 100, 221801 (2008); D. Asner et al., Phys. Rev. D 78, 012001 (2008).

[6] D. Atwood and A. Soni, Phys Rev. D 68, 033003 (2003).

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[hep-ex] (2008),andonline updateat

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