[Paper Review] D-0-(D)over-bar(0) mixing in Upsilon(1S)-> D-0(D)over-bar(0) decay at a super-B factory

Hai-Bo Li, 杨茂志+2 more|arXiv (Cornell University)|Nov 1, 2006

Particle physics theoretical and experimental studies9 citations

TL;DR

This paper proposes using coherent D⁰D̄⁰ pairs produced in Upsilon(1S) → D⁰D̄⁰ decays at a super-B factory to measure D⁰-D̄⁰ mixing and CP violation. The high boost of the D mesons enables precise time-dependent measurements of the proper-time interval Δt, allowing extraction of mixing parameters and CP-violation observables with improved sensitivity compared to existing methods.

ABSTRACT

D-0-(D) over bar (0) mixing and significant CP violation in the charm system may indicate the signature of new physics. In this study, we suggest that the coherent D-0(D) over bar (0) events from the decay of Upsilon(1S)-> D-0(D) over bar (0) can be used to measure both mixing parameters and CP violation in charm decays. The neutral D mesons from Upsilon(1S) decay are strongly boosted, so that it will offer the possibility to measure the proper-time interval Delta t between the fully reconstructed D-0 and (D) over bar (0). Both coherent and time-dependent information can be used to extract D-0-(D) over bar (0) mixing parameters. The sensitivity of the measurement should be improved at B factories or at super-B.

Motivation & Objective

• To explore D⁰-D̄⁰ mixing and CP violation in charm decays as potential signatures of new physics.
• To address the challenge of measuring small mixing parameters and CP asymmetries in the charm system with high precision.
• To leverage the coherent D⁰D̄⁰ pair production in Upsilon(1S) decays for improved sensitivity to mixing and CP-violation parameters.

Proposed method

• Utilize coherent D⁰D̄⁰ pairs produced in Upsilon(1S) → D⁰D̄⁰ decays at a super-B factory.
• Reconstruct both D⁰ and D̄⁰ mesons fully to determine their decay times.
• Measure the proper-time interval Δt between the two D mesons using their flight paths and momenta.
• Apply time-dependent amplitude analysis to extract mixing parameters and CP-violation observables.
• Combine coherent state information with time-dependent decay rate analysis to enhance sensitivity.
• Use the high boost of the D mesons to resolve small Δt differences, enabling precise measurement of mixing parameters.

Experimental results

Research questions

• RQ1 Can coherent D⁰D̄⁰ pairs from Upsilon(1S) decays be used to measure D⁰-D̄⁰ mixing parameters with improved sensitivity?
• RQ2 How does the high boost of D mesons in Upsilon(1S) → D⁰D̄⁰ decays enhance the measurement of the proper-time interval Δt?
• RQ3 To what extent can time-dependent and coherent analysis reduce systematic uncertainties in measuring CP violation in charm decays?
• RQ4 What is the potential sensitivity gain of this method compared to existing charm mixing measurements?

Key findings

• The high boost of D mesons in Upsilon(1S) → D⁰D̄⁰ decays enables precise measurement of the proper-time interval Δt between the two D mesons.
• Coherent D⁰D̄⁰ pairs allow simultaneous extraction of mixing parameters and CP-violation observables through time-dependent amplitude analysis.
• The method provides improved sensitivity to D⁰-D̄⁰ mixing and CP violation compared to conventional approaches.
• The use of fully reconstructed D⁰ and D̄⁰ decays enhances the accuracy of time-interval measurements.
• The proposed technique is particularly suited for super-B factories due to their high luminosity and clean initial state.
• The combination of coherence and time dependence offers a powerful tool to probe new physics in the charm sector.