The B^0_s -> J/psi K_S decay has recently been observed by the CDF collaboration and will be of interest for the LHCb experiment. It is the U-spin partner of the golden B^0_d -> J/psi K_S channel and offers a determination of the angle gamma of the unitarity triangle. Moreover, it allows us to control the hadronic penguin effects in the extraction of the B^0_d-\bar B^0_d mixing phase phi_d through a measurement of CP violation in B^0_d^0 -> J/psi K_S. We discuss the picture emerging for these measurements from an LHCb feasibility study. While LHCb will be able to extract gamma from the CP violation in B^0_d -> J/psi K_S, the main application of this channel will be the determination of hadronic penguin parameters. Such an analysis is actually needed in order to fully exploit LHCb's impressive experimental precision for the determination of phi_d from B^0_d -> J/psi K_S. We give also the target regions for the effective lifetime of B^0_s -> J/psi K_S and its CP-violating observables for improved measurements by CDF and the 2011 data taking at LHCb.
The B_s^0 -> J/psi K_S decay has recently been observed by the CDF collaboration and will be of interest for the LHCb experiment. This channel will offer a new tool to extract the angle gamma of the unitarity triangle and to control doubly Cabibbo-suppressed penguin corrections to the determination of sin(2beta) from the well-known B_d^0 -> J/psi K_S mode with the help of the U-spin symmetry of strong interactions. While any competitive determination of gamma is interesting, the latter aspect is particularly relevant as LHCb will enter a territory of precision which makes the control of doubly…
Performing a fit to the available experimental data, we quantify the effect of long-distance contributions from penguin contractions in B^0 to J/psi K^0 decays. We estimate the deviation of the measured S_CP term of the time-dependent CP asymmetry from sin(2 beta) induced by these contributions and by the penguin operators. We find Delta S = 0.000 +- 0.012 ([-0.025,0.024] @ 95% probability).
We study the penguin pollution in the B^0 -> J/psi K_S decay up to leading power in 1/m_b and to next-to-leading order in α_s, m_b being the b quark mass and α_s the strong coupling constant. The deviation ΔS_{J/psi K_S} of the mixing-induced CP asymmetry from sin(2ϕ_1) and the direct CP asymmetry A_{J/psi K_S} are both found to be of O(10^{-3}) in a formalism that combines the QCD-improved factorization and perturbative QCD approaches.
The high precision to which the standard model has been confirmed implies that new physics effects have to be small in the observed processes. Together with the outstanding precision expected from present and future collider experiments this renders the evaluation of subleading SM contributions necessary. For the "golden mode", B_d to J/Psi K, these so-called "penguin pollution" terms can be controlled by using flavour symmetry relations. A recent analysis is presented which yields a stronger bound on the maximal penguin influence than previous ones and shows how the corresponding uncertainty …
We present the most complete analysis of the penguin correction to the extraction of the standard-model parameter sin(2ϕ_1) from the B^0 -> J/psi K_S decay up to leading power in 1/m_b and to next-to-leading order in α_s, ϕ_1 being the weak phase, m_b the b quark mass, and α_s the strong coupling constant. The deviation ΔS_{J/psi K_S} of the mixing-induced CP asymmetry from sin(2ϕ_1) and the direct CP asymmetry A_{J/psi K_S} are both found to be of O(10^{-3}) in a formalism that combines the QCD-improved factorization and perturbative QCD approaches. The above results, different from those of …
We derive constraints for $B\to VV$ modes ($V= vector meson) that allow aquantitative assessment of the contributions from electroweak penguins (EWP) and/or new physics. Interplay of direct CP with oscillation studies then leads to the extraction of the angles alpha and gamma, using B--> K* omega rho and B--> rho omega (phi) respectively, if by using our constraint equations it can be experimentally demonstrated that color-suppressed EWP are small.
The charm quark offers interesting opportunities to cross-check the mechanism of CP violation precisely tested in the strange and beauty sectors. In this paper, we exploit the angular and quantum correlations in the D\bar{D} pairs produced through the decay of the psi(3770) resonance in a charm factory to investigate CP-violation in two different ways. We build CP-violating observables in psi(3770) -> D\bar{D} -> (V_1V_2)(V_3 V_4) to isolate specific New Physics effects in the charm sector. We also consider the case of psi(3770) -> D\bar{D} -> (V_1V_2)(Kπ) decays, which provide a new way to me…
Estimates of the branching ratios for B_{d,s}->J/psi eta and B_{d,s}->eta l+l- are obtained by SU(3) relation to B_d->J/psi K and B_d->K l+l-, respectively, as functions of the eta mixing parameter, theta_P. Based on these estimates, a discussion of the prospects for HERA-B, CDF-II, and ATLAS on these processes is given. The CP violation in B_{d,s}-> J/psi eta is analyzed in depth and a method to extract the angle gamma of the unitarity triangle is discussed. Finally, a possible method to constrain the Wilson coefficient C_{10A} from measurements on semileptonic B decays such as B_d->J/psi K a…
The extraction of the CKM angle $α$ from the asymmetry in $B^0 \to π^+π^-$ vs ${\bar B^0} \to π^+π^-$ suffers from a currently unknown penguin contribution. Experimentally, one can determine the magnitude and phase of the CP asymmetry from a time-dependent analysis of tagged events, and the average rate for $B^0$ and $\bar{B}^0$ decays to $π^+π^-$ from untagged events. These measurements, together with the magnitudes and relative phase of the tree and penguin diagrams, can in principle completely determine $α$, free of discrete ambiguities. We perform an error analysis on $α$ given assumptions…
The time-dependent angular distributions of certain $B_{d,s}$ decays into final states that are admixtures of CP-even and CP-odd configurations provide valuable information about CKM phases and hadronic parameters. We present the general formalism to accomplish this task, taking also into account penguin contributions, and illustrate it by considering a few specific decay modes. We give particular emphasis to the decay $B_d\to J/ψρ^0$, which can be combined with $B_s\to J/ψϕ$ to extract the $B^0_d - \bar{B^0_d}$ mixing phase and - if penguin effects in the former mode should be sizeable - also…
The B^0 -> J/ψK_{S,L} channels are outstanding probes of CP violation. We have a detailed look at the associated Standard-Model uncertainties, which are related to doubly Cabibbo-suppressed penguin contributions, and point out that these usually neglected effects can actually be taken into account unambiguously through the CP asymmetries and the branching ratio of the B^0 -> J/ψpi^0 decay. Using the most recent B-factory measurements, we find a negative shift of the extracted value of beta, which softens the tension in the fits of the unitarity triangle. In addition, this strategy can be used …
We compute the O(alpha_s^2) correction to the decay rate eta_c --> gamma gamma and discuss its implications for precision quarkonium physics. We study the suitability of the ratio Gamma(J/psi --> e+e-)/Gamma(eta_c --> gamma gamma), in which the non-perturbative or soft effects cancel at O(alpha_s^{0,1}), for extracting fundamental parameters of QCD at low energies. We show that the QCD-based theory of charmonia is not capable of predicting this ratio with any degree of confidence.
We discuss various issues related to the definition of single and double open charm cross sections. We conclude that LHCb's extraction of sigma_effective, the effective cross section for double-parton scattering, is too large by a factor of two. This correction brings the data from open-charm pairs closer to that from J/psi plus open charm and jet production.
The effect of the penguin amplitude on extracting $α$ from CP asymmetries in $B^0\to ρ^+ρ^-$ decays is studied using information on the SU(3)-related penguin amplitude in $B^+\to K^{*0}ρ^+$. Conservative bounds on non-factorizable SU(3) breaking, small amplitudes, and the strong phase difference between tree and penguin amplitudes, are shown to reduce the error in $α$ in comparison with the one obtained using isospin symmetry in $B\toρρ$. Current measurements imply $α= [90 \pm 7 f{\rm exp})^{+2}_{-5} ({\rm th})]^\circ$.
We have studied extracting $|\vub/\vcb|$ by calculating the ratios ${\cal B}(\bar{B}^0\to D_s^{(*)-}(π^+,ρ^+))/{\cal B}(\bar{B}^0\to D_s^{(*)-}D^{(*)+})$ including penguin effects within the factorization assumption. The ratios involving $\bar{B}^0\to D_s^-D^{+}$ mode have considerable penguin corrections ($\sim 15%$ at the amplitude level), but those involving $\bar{B}^0\to D_s^-D^{*+}$ mode have relatively small penguin corrections. On the other hand, the $\bar{B}^0\to D_s^-D^{+}$ mode has smaller form-factor dependance. Therefore, these ratios complement each other in measuring $\vub/\vcb$.…
In this paper we study the impact of data that can be obtained from a Charm Factory on the determination of the CKM parameter gamma from decays of the form B -> D0 K where the D0 decays to specific inclusive and exclusive final states. In particular, for each exclusive final state $f$, the charm factory can determine the strong phase difference between D0-> f and D0-bar -> f by exploiting correlations in psi(3770)-> D0 D0-bar. This provides crucial input to the determination of gamma via the interference of B+- -> K+- D0 -> f with B+- -> K+- D0-bar -> f. We discuss how the method may be genera…
The recent observation of B_d -> pi^0 pi^0 at the B factories with a surprisingly large branching ratio represents a challenge for theory, and complements the amazingly small B_d -> pi^+ pi^- rate. We point out that all puzzling B -> pi pi features can be accommodated in the Standard Model (SM) through non-factorizable hadronic interference effects, extract the relevant parameters, and predict the CP asymmetries of B_d -> pi^0 pi^0. Using then SU(3) flavour-symmetry and plausible dynamical assumptions, we fix the hadronic B -> pi K parameters through their B -> pi pi counterparts, and determin…
The process of exclusive vector meson production (gamma gamma to J/psi rho^0) is studied for almost real photons. This process may be reduced to photoproduction of J/psi off the rho^0 meson. We discuss the possibility of extracting the gluon distribution of rho^0 and of the photon from such measurement. Predictions are also given for the reaction (e+e- to e+ e- J/psi rho^0) for various e+e- cms energies typical for LEP and for the future linear colliders.
The recently observed color-suppressed B0bar to D0 pi0, D0 eta, D0 eta', Ds+ K-, D0 K0bar, D0 rho0 and D0 omega decay modes all have rates larger than expected. The color-suppressed Bs to D0 phi, D0bar phi modes, which were suggested for the extraction of the unitarity angle gamma in the Gronau-London method, could be larger than the previous estimation by one order of magnitude. Several new theoretical clean modes in Bs decays are suggested for the extraction of gamma. The proposed Bs to D0 h0, D0bar h0 decay modes with h0 = pi0, eta, eta', rho0, omega in addition to h0 = phi are free from pe…
The decay channels $B_d^0 \to D^{*0} K^{*0}$ are investigated for extracting weak $CKM$ phase information. These channels are described by color-suppressed tree diagrams only and are free from penguin contributions. The branching ratios for these channels are found to be $\sim \cal O $ $(10^{-5} - 10^{-6})$ which can be measured at the currently running $B$ factories. The method presented here may be well-suited to determine the phase $γ$.
