Publications (6)3.63 Total impact
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Article: Exploring CP violation and η–η′ mixing with the systems
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ABSTRACT: The B0s,d ® J/yh(¢)B^{0}_{s,d} \to J/\psi \eta^{(\prime)} decays provide new terrain for exploring CP violation. After briefly discussing η–η′ mixing, we analyse the effective lifetimes and CP-violating observables of the B s channels, which allow us to probe New-Physics effects in B0sB^{0}_{s}–[`(B)]0s\bar{B}^{0}_{s} mixing. We have a critical look at these observables and show how hadronic corrections can be controlled by means of the B d decays. Using measurements of the B0s,d® J/yh(¢)B^{0}_{s,d}\to J/\psi \eta^{(\prime)} branching ratios by the Belle collaboration, we discuss tests of the SU(3)F flavour symmetry of strong interactions, obtain the first constraints on the hadronic parameters entering the B0s,d ® J/yhB^{0}_{s,d} \to J/\psi \eta system, and predict the B0d® J/yh¢B^{0}_{d}\to J/\psi \eta' branching ratio at the 5×10−6 level. Furthermore, we present strategies for the determination of the η–η′ mixing parameters from the B0s,d ® J/yh(¢)B^{0}_{s,d} \to J/\psi \eta^{(\prime)} observables. We also observe that the B0s,d ® J/yhB^{0}_{s,d} \to J/\psi \eta and B0s,d ® J/yh¢B^{0}_{s,d} \to J/\psi \eta' decays are—from a formal point of view—analogous to the quark–antiquark and tetraquark descriptions of the f 0(980) in the B0s,d ® J/yf0(980)B^{0}_{s,d} \to J/\psi f_{0}(980) channels, respectively.European Physical Journal C 05/2012; 71(11):1-10. · 3.63 Impact Factor -
Article: Exploring CP Violation and $\eta$-$\eta'$ Mixing with the $B^0_{s,d} \to J/\psi \eta^{(\prime)}$ Systems
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ABSTRACT: The $B^0_{s,d} \to J/\psi \eta^{(\prime)}$ decays provide new terrain for exploring CP violation. After briefly discussing $\eta$-$\eta'$ mixing, we analyse the effective lifetimes and CP-violating observables of the $B_s$ channels, which allow us to probe New-Physics effects in $B^0_s$-$\bar B^0_s$ mixing. We have a critical look at these observables and show how hadronic corrections can be controlled by means of the $B_d$ decays. Using measurements of the $B^0_{s,d}\to J/\psi \eta^{(\prime)}$ branching ratios by the Belle collaboration, we discuss tests of the $SU(3)_F$ flavour symmetry of strong interactions, obtain the first constraints on the hadronic parameters entering the $B^0_{s,d} \to J/\psi \eta$ system, and predict the $B^0_d\to J/\psi \eta'$ branching ratio at the $5\times10^{-6}$ level. Furthermore, we present strategies for the determination of the $\eta$-$\eta'$ mixing parameters from the $B^0_{s,d} \to J/\psi \eta^{(\prime)}$ observables. We also observe that the $B^0_{s,d} \to J/\psi \eta$ and $B^0_{s,d} \to J/\psi \eta'$ decays are - from a formal point of view - analogous to the quark-antiquark and tetraquark descriptions of the $f_0(980)$ in the $B^0_{s,d} \to J/\psi f_0(980)$ channels, respectively.10/2011; -
Article: Effective Lifetimes of $B_s$ Decays and their Constraints on the $B_s^0$-$\bar B_s^0$ Mixing Parameters
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ABSTRACT: Measurements of the effective lifetimes of $B_s$-meson decays, which only require untagged rate analyses, allow us to probe the width difference $\Delta\Gamma_s$ and the CP-violating phase $\phi_s$ of $B^0_s$-$\bar B^0_s$ mixing. We point out that the dependence of the effective lifetime on non-linear terms in $\Delta\Gamma_s$ allows for a determination of $\phi_s$ and $\Delta\Gamma_s$ given a pair of $B_s$ decays into CP-even and CP-odd final states. Using recent lifetime measurements of $B^0_s\to K^+K^-$ and $B^0_s\to J/\psi f_0(980)$ decays, we illustrate this method and show how it complements the constraints in the $\phi_s$-$\Delta\Gamma_s$ plane from other observables.09/2011; -
Article: Anatomy of $B^0_{s,d} \to J/\psi f_0(980)$
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ABSTRACT: The $B^0_s\to J/\psi f_0(980)$ decay offers an interesting experimental alternative to the well-known $B^0_s\to J/\psi \phi$ channel for the search of CP-violating New-Physics contributions to $B^0_s$--$\bar B^0_s$ mixing. As the hadronic structure of the $f_0(980)$ has not yet been settled, we take a critical look at the implications for the relevant observables and address recent experimental data. It turns out that the effective lifetime of $B^0_s\to J/\psi f_0(980)$ and its mixing-induced CP asymmetry $S$ are quite robust with respect to hadronic effects and thereby allow us to search for a large CP-violating $B^0_s$--$\bar B^0_s$ mixing phase $\phi_s$, which is tiny in the Standard Model. However, should small CP violation, i.e. in the range $-0.1\lsim S\lsim 0$, be found in $B^0_s\to J/\psi f_0(980)$, it will be crucial to constrain hadronic corrections in order to distinguish possible New-Physics effects from the Standard Model. We point out that $B^0_d\to J/\psi f_0(980)$, which has not yet been measured, is a key channel in this respect and discuss the physics potential of this decay.09/2011; -
Article: A Fresh Look at B_{s,d} -> pi pi, pi K, K K Decays
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ABSTRACT: Using updated measurements and SU(3)-breaking form factors, we have a detailed look at the B_d -> pi^+ pi^-, B_s -> K^+ K^- and B_d -> pi^\mp K^\pm, B_s -> pi^\pm K^\mp systems. The corresponding decays are related to each other by the U-spin symmetry of strong interactions and offer determinations of the angle gamma of the unitarity triangle. In the former case, we obtain gamma=(68.3^{+4.8}_{-5.7}^{+5.0}_{-3.7}) deg, which is in excellent agreement with the Standard-Model fits of the unitarity triangle. The first errors correspond to experimental input uncertainties, while the latter are an estimate of U-spin-breaking effects. In view of this result, large CP-violating new-physics effects at the amplitude level are excluded. However, the effective B_s -> K^+ K^- lifetime and the mixing-induced CP violation in this channel offer interesting probes for New Physics in B^0_s-\bar B^0_s mixing. In the case of the B_d -> \pi^\mp K^\pm, B_s -> pi^\pm K^\mp system, using additional information from B^\pm -> \pi^\pm K, we obtain a bound of gamma \leq (71.8^{+5.4}_{-4.3}) deg, and the range 24 deg \leq gamma \leq 71 deg. We perform also tests of the U-spin symmetry and do not find any indication for large non-factorizable corrections.12/2010; -
Article: In Pursuit of New Physics with B^0_s -> K^+K^-
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ABSTRACT: The B^0_s -> K^+K^- decay is the U-spin partner of B^0_d -> pi^+\pi^- and allows a determination of the angle gamma of the unitarity triangle of the Cabibbo-Kobayashi-Maskawa matrix. Using updated information on the branching ratio and the relevant hadronic form factors, we discuss the picture that emerges for gamma from the currently available data, which is in good agreement with the fits of the unitarity triangle. We point out that the B^0_s -> K^+K^- decay also offers interesting probes to search for new physics in B^0_s-\bar B^0_s mixing, thereby complementing the well-known B^0_s -> J/psi phi analyses. The relevant observables are the effective lifetime of this channel and its mixing-induced CP asymmetry. We calculate correlations between these quantities and the CP-violating B^0_s-\bar B^0_s mixing phase, which serve as target regions for improved measurements at the Tevatron and the early data taking at the LHCb experiment. Finally, we discuss the expected situation for the optimal determination of gamma at LHCb, exploiting precise measurements of the CP violation in B^0_s -> K^+K^-.11/2010;
