The CKM paradigm has been tested thoroughly over the last 40 years in both the neutral $K$ and $B$ systems. The recent discovery of neutral charm meson mixing has prompted the search for CP violation in $D$ decays. We discuss the prospects of performing time-dependent CP asymmetry measurements at facilities either taking data or under construction. Such measurements can (i) provide precision determinations of the charm mixing phase, and (ii) be used to probe for possible new physics effects (and perhaps ultimately constrain the CKM paradigm). We propose the use of the time-dependent asymmetry measurement of $D^0 \to K^+K^-$ decays to measure the phase of charm mixing, where existing experiments that are either under construction or taking data should be able to reach a precision of $<1.5^\circ$, and to use the phase difference between $D^0 \to K^+K^-$ and $D^0 \to π^+π^-$ decays to constrain the angle $β_c$ of the $cu$ unitarity triangle up to theoretical uncertainties from long distance and loop contributions. A large phase difference measured between these modes would indicate new physics.
The asymmetries between charm and anticharm mesons observed in fixed-target photoproduction experiments are an order of magnitude larger than the asymmetries predicted by conventional perturbative QCD. We show that these charm meson asymmetries can be explained by a heavy-quark recombination mechanism for heavy meson production. In this process, a charm quark combines with a light antiquark from the hard-scattering process and they subsequently hadronize into a state including the charm meson. This recombination mechanism can be calculated within perturbative QCD up to some nonperturbative con…
Charm asymmetries in fixed-target hadroproduction experiments are sensitive to power corrections to the QCD factorization theorem for heavy quark production. A power correction called heavy-quark recombination has recently been proposed to explain these asymmetries. In heavy-quark recombination, a light quark or antiquark participates in a hard scattering which produces a charm-anticharm quark pair. The light quark or antiquark emerges from the scattering with small momentum in the rest frame of the charm quark, and together they hadronize into a charm particle. The cross section for this proc…
We study the effects of models with a warped extra dimension on rare charm decays. While the new degrees of freedom in these models are bounded above a few TeV, they can leave signatures in rare charm decays with their tiny Standard Model background. We look at several channels with leptons in the final state along with several asymmetries of both kinematical and dynamical nature. CPT invariance is `usable' for analyzing the impacts of new dynamics in $D$ meson decays and in particular, rare decays of charm mesons.
We find a new $CP$-violation effect in charm decays into neutral kaons, which results from the interference between two tree (Cabibbo-favored and doubly Cabibbo-suppressed) amplitudes with the mixing of final-state mesons. This effect, estimated to be of an order of $10^{-3}$, is much larger than the direct $CP$ asymmetries in these decays, but missed in the literature. It can be revealed by measuring the difference of the time-dependent $CP$ asymmetries in the $D^{+}\toπ^{+}K_S^0$ and $D_{s}^{+}\to K^{+} K_S^0$ modes, which are accessible at the LHCb and Belle II experiments. If confirmed, th…
Nonleptonic two body B decays including radially excited $π(1300)$ or $ρ(1450)$ mesons in the final state are studied using the framework of generalized naive factorization approach. Branching ratios and CP asymmetries of $B\to Pπ(1300)$, $B\to Vπ(1300)$, $B\to Pρ(1450)$ and $B\to Vρ(1450)$ decays are calculated, where P and V stand for pseudoscalar and vector charmless mesons. Form factors for $B\to π(1300)$ and $B\to ρ(1450)$ transitions are estimated in the improved version of the Isgur-Scora-Grinstein-Wise quark model. In some processes, CP asymmetries of more than 10% and branching ratios…
We propose a theoretical framework to understand the observable charge-parity (CP) violation in charmless three-body $B^\pm$ decays. The decay amplitudes put together the $ππ\to KK $ re-scattering and the U-spin symmetry, treated within a CPT invariant framework. This approach applied to a two-channel model provides the magnitudes and signs of the ratios of the global CP asymmetries for $B^\pm \to K^\pm π^+ π^- \,$, $B^\pm \to K^\pm K^+ K^- \,$, $B^\pm \to π^\pm K^+ K^- \,$ and $B^\pm \to π^\pm π^+π^- \,$ decays, compatible with those obtained from the available experimental data. In addition,…
We study the up-down asymmetries in the three-body anti-triplet charmed baryon decays of ${\bf B_c}\to{\bf B_n}MM' $ with the $SU(3)_f$ flavor symmetry, where ${\bf B_c}$ presents the anti-triplet charmed baryon of $(Ξ_c^0,-Ξ_c^+,Λ_c^+)$, while ${\bf B_n}$ and $M^{(')}$ denote octet baryon and meson states, respectively. By assuming the s-wave meson-pairs to be the dominant constituents in final state configurations, we can write the spin-dependent decay amplitude into parity-conserving and parity-violating parts, parametrized by 6 real parameters under $SU(3)_f$, respectively. Fitting these p…
The forward-backward asymmetry A_{FB}^t in top quark production at the Tevatron has been seen to be anomalously large both by CDF and D0. Parton-level asymmetries as large as 50%, with a large error bar, have been extracted from the data. It is important to measure other quark asymmetries if possible, as these would help clarify the source of any new physics behind A_{FB}^t. In this note it is argued that asymmetries in b\bar b and c\bar c should be accessible to the Tevatron experiments, using the full data sets. A crude study suggests that muon asymmetries in high-p_T dijet events, with suit…
We present recent results on time integrated and time dependent CP violation for charmless hadronic B decays using BABAR detector at the PEP-II B-factory.
We analyze patterns from CP-violating new physics (NP) in hadronic and semileptonic rare charm $\vert Δc \vert=\vert Δu\vert=1$ transitions. Observation of direct CP-violation in hadronic decays, as in $ΔA_{\text{CP}}$, provides opportunities for $c \to u \,\ell^+ \ell^-$, $\ell=e,μ$ transitions, and vice versa. For the concrete case of flavorful, anomaly-free $Z^\prime$-models a NP-interpretation of $ΔA_{\text{CP}}$ suggests measurable CP-asymmetries in semileptonic decays such as $D \to π\, \ell^+ \ell^-$ or $D \to ππ\, \ell^+ \ell^-$. Conversely, an observation of CP-violation in $c \to u\,…
The LHCb collaboration has recently performed a first measurement of the angular production asymmetry in the distribution of beauty quarks and anti-quarks at a hadron collider. We calculate the corresponding standard model prediction for this asymmetry at fixed-order in perturbation theory. Our results show good agreement with the data, which is provided differentially for three bins in the invariant mass of the $b \bar b$ system. We also present similar predictions for both beauty-quark and charm-quark final states within the LHCb acceptance for a collision energy of $\sqrt{s} = 13 \, {\rm Te…
Asymmetries in the hadroproduction of charm particles directly probe power corrections to the QCD factorization theorems. In this paper, the heavy-quark recombination mechanism, a power correction that explains charm meson asymmetries, is extended to charm baryons. In this mechanism, a light quark participates in the hard scattering that creates a charm quark and they hadronize together into a charm baryon. This provides a natural and economical explanation for the Λ_c^+/Λ_c^- asymmetries measured in πN and p N collisions.
We present measurements of branching fraction, polarization and charge asymmetry in charmless hadronic B decays with eta, eta', omega, and b_1 in the final state. All the results use the final BABAR dataset.
We report branching fractions and charge asymmetries for exclusive decays of charged and neutral B mesons to two-body final states containing a charmonium meson, J/psi or psi(2S). This result is based on a 29.4 fb^{-1} data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e+e- collider.
We analyze the decay processes of ${\bf B}_c \to {\bf B}_n M$ with the $SU(3)_F$ flavor symmetry and spin-dependent amplitudes, where ${\bf B}_c({\bf B}_n)$ and $M$ are the anti-triplet charmed (octet) baryon and nonet meson states, respectively. In the $SU(3)_F$ approach, it is the first time that the decay rates and up-down asymmetries are fully and systematically studied without neglecting the ${\cal O}(\overline{15})$ contributions of the color anti-symmetric parts in the effective Hamiltonian. Our results of the up-down asymmetries based on $SU(3)_F$ are quite different from the previous …
The use of triple-product correlations is described in relation to the search for $CP$ violation in 4-body charm meson decays. The latest results from the LHCb and BaBar Collaborations are reported. A novel interpretation of the asymmetries from triple-product correlations is used for the BaBar results, which enables the extraction of information on the properties of $D$ decays under parity and charge-conjugation transformations.
We report measurements of branching fractions and charge asymmetries of exclusive decays of neutral and charged B mesons into two-body final states containing a charmonium state and a light strange meson. The charmonium mesons considered are J/Psi, Psi(2S) and Chi_c1, and the light meson is either K or K*. We use a sample of about 124 million BBbar events collected with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center.
We search for CP violating asymmetries in five charmless hadronic B meson decays using the full CLEO II and CLEO II.V data samples totalling 9.7 million BBbar events. The resulting Acp measurements have a precision that varies from +-0.12 to +-0.25 (absolute) depending on mode. No significant nonzero asymmetry is observed in any mode but 90% CL limits are strong and rule out some estimates of Acp.
We examine the validity of the generalized factorization method and calculate the angular correlations in the charmful three-body baryonic decays of $\bar B^0\to Λ\bar p D^{(*)+}$. With the timelike baryonic form factors newly extracted from the measured baryonic $B$ decays, we obtain ${\cal B}(\bar B^0\to Λ\bar p D^+,Λ\bar p D^{*+})=(1.85\pm 0.30,2.75\pm 0.24)\times 10^{-5}$ to agree with the recent data from the BELLE Collaboration, which demonstrates that the theoretical approach based on the factorization still works well. For the angular distribution asymmetries, we find ${\cal A}_θ(\bar …
We report measurements of the charm-anticharm production asymmetries for $Λ_c^+$, $Σ_c^{++}$, $Σ_c^0$, $Σ_c^{++*}$, $Σ_c^{0*}$, and $Λ_c^+(2625)$ baryons from the Fermilab photoproduction experiment FOCUS (E831). These asymmetries are integrated over the region where the spectrometer has good acceptance. In addition, we have obtained results for the photoproduction asymmetries of the $Λ_c$ baryons as functions of $p_L$, $p_T^2$, and $x_F$. The integrated asymmetry for $Λ_c^+$ production, $(σ_{Λ_c^+} - σ_{Λ_c^-}) / (σ_{Λ_c^+} + σ_{Λ_c^-})$, is $0.111 \pm 0.018 \pm 0.012$, significantly differen…
We search for CP-violating asymmetries (Acp) in the B meson decays to K+- pi-+, K+- pi0, Ks pi+-, K+- eta', and omega pi+-. Using 9.66 million Upsilon(4S) decays collected with the CLEO detector, the statistical precision on Acp is in the range of \pm 0.12 to \pm 0.25 depending on decay mode. While CP-violating asymmetries of up to \pm 0.5 are possible within the Standard Model, the measured asymmetries are consistent with zero in all five decay modes studied.
With a sample of approximately 89 million BBbar pairs collected with the BABAR detector, we perform a search for B meson decays into pairs of charmless vector mesons (phi, rho, and K*). We measure the branching fractions, determine the degree of longitudinal polarization, and search for CP violation asymmetries in the processes B->phiK*+, B->phiK*0, B->rho0K*+, and B->rho0rho+. We also set an upper limit on the branching fraction for the decay B->rho0rho0.
We have measured, with electron tagging, the forward-backward asymmetries of charm- and bottom-quark pair productions at $<\sqrt{s} >$=58.01GeV, based on 23,783 hadronic events selected from a data sample of 197pb$^{-1}$ taken with the TOPAZ detector at TRISTAN. The measured forward-backward asymmetries are $A_{FB}^c = -0.49 \pm 0.20(stat.) \pm 0.08 (sys.)$ and $A_{FB}^b = -0.64 \pm 0.35(stat.) \pm 0.13 (sys.)$, which are consistent with the standard model predictions.
New physics (NP) in charmless strangeness-changing $B$ and $B_s$ decays, which are dominated by the $b \to s$ penguin amplitudes, can either preserve isospin or change it by one unit. A general formalism is presented studying pairs of processes related to each other by isospin reflection. We discuss information on $ΔI$ in NP amplitudes, provided by time-integrated CP-violating rate asymmetries in $B^+$ and $B^0$ decays (or in $B_s$ decays), differences between rates for isospin-reflected processes, and coefficients $S$ of $\sin Δm t$ in time-dependent CP asymmetries. These four asymmetries in …
We present new CDF results on the branching fractions and time-integrated direct CP asymmetries for $B^0$ and $B^0_s$ decay modes into pairs of charmless charged hadrons (pions or kaons). The data-set for this update amounts to 1 $\mathrm{fb}^{-1}$ of $p\bar p$ collisions at a center of mass energy 1.96 $\mathrm{TeV}$. We report the first observation of the $B_s \to K^- π^+$ mode and a measurement of its branching fraction and direct CP asymmetry. We also observe for the first time two charmless decays of the $Λ_b^0$-baryon: $Λ_b^0 \to pπ^-$ and $Λ_b^0 \to pK^-$.
We consider longitudinal, parity-violating single-spin asymmetries in proton-proton collisions at RHIC. The focus of this study is on the production of single-inclusive jets, as well as on jets that contain a charm quark. While the asymmetry for inclusive jets turns out to be small, we find considerably larger effects for the case of charm production. We also investigate the role of leading threshold logarithms and find that they increase the polarized and unpolarized cross sections and reduce the spin asymmetry.
We present new CDF results on the branching fractions and time-integrated direct CP asymmetries for $B^{0}$ and $B^{0}_{s}$ decay modes into pairs of charmless charged hadrons (pion or kaon). The data set for this update amounts to 1 fb$^{-1}$ of $\bar{p}p$ collisions at $\sqrt{s}=1.96 \rm{TeV}$. We report the first observation of the $B^{0}_{s} \to K^{-}π^{+}$ mode and a measurement of its branching fraction and direct CP asymmetry. We also observe for the first time two charmless decays of $b$-baryon: $Λ^{0}_{b} \to pπ^{-}$ and $Λ^{0}_{b} \to pK^{-}$.
$CP$ violation asymmetry is expected to be very small within the Standard Model. Observation of $CP$ violation in charm sector would hint towards New Physics. Time-reversal asymmetry is sensitive to $CPV$ via the $CPT$ Theorem, and is a clean and alternative way to search for CP violation in charm decays. This is achieved by the use of triple-product correlations in 4-body charm meson decays. The results from previous searches at BaBar and LHCb Collaborations and the latest results from Belle are reported. The most recent result from Belle performed in $D^{0} \to K^{+}K^{-}π^{+}π^{-}$ decays u…
We present estimates of the direct (in decay amplitudes) and indirect (mixing- induced) CP-violating asymmetries in the non-leptonic charmless two-body decay rates for $B \to PP$, $B \to PV$ and $B \to VV$ decays and their charged conjugates, where P(V) is a light pseudoscalar (vector) meson. These estimates are based on a generalized factorization approach making use of next-to-leading order perturbative QCD contributions which generate the required strong phases. No soft final state interactions are included. We study the dependence of the asymmetries on a number of input parameters and show…
The knowledge of charm production asymmetries is an important prerequisite for many of the possible searches for CP violation in charm. Measurements of these asymmetries at hadron colliders can also help to improve our understanding of QCD. These proceedings review existing measurements and discuss some of the experimental challenges of determining charge asymmetries at the per-mille level.
We propose for the first time a method to perform analysis of time-dependent CP asymmetries in charm by using both, correlated and un-correlated $D^0$ mesons. Here we consider the decay channels $D^0\to K^+ K^-$ and $D^0\to π^+ π^-$. The channel $D^0\to K^+ K^-$ will be used to measure the mixing phase, and the difference between the measured phase $D^0\to K^+ K^-$ and $D^0\to π^+ π^-$ will open the door to the first measurement of $β_c$, one of the angle of the charm unitarity triangle. Since in the standard model CP asymmetries in charm are expected to be small, any observation of large time…
We present measurements of branching fractions and charge asymmetries for charmless B-meson decays to three-body final states of charged pions and kaons. The analysis uses 81.8 fb^-1 of data collected at the Upsilon(4S) resonance with the BaBar detector at the SLAC PEP-II asymmetric B Factory. We measure the branching fractions B(B+ -> pi+ pi- pi+) = (10.9 +/- 3.3 +/- 1.6) x 10^-6, B(B+ -> K+ pi- pi+) = (59.1 +/- 3.8 +/- 3.2) x 10^-6, and B(B+ -> K+ K- K+) = (29.6 +/- 2.1 +/- 1.6) x 10^-6, and provide 90% C.L. upper limits for other decays. We observe no charge asymmetries for these modes.
We report a measurement of the difference (Delta Acp) between time-integrated CP--violating asymmetries in D0-> K+ K- and D0-> pi+pi- decays reconstructed in the full data set of proton-antiproton collisions collected by the Collider Detector at Fermilab, corresponding to 9.7 fb-1 of integrated luminosity. The strong decay D*+->D0 pi+ is used to identify the charm meson at production as D0 or anti-D0. We measure Delta Acp = [-0.62 +- 0.21 (stat) +- 0.10 (syst)] %, which differs from zero by 2.7 Gaussian standard deviations.This result supports similar evidence for CP violation in charm-quark d…
Hadronic $B$ decays without a charm quark constitute a powerful probe to search for physics beyond the standard model as well as to provide constraints on $CP$ violation parameters. We report final measurements from Belle of the branching fractions and $CP$ asymmetries for the decays $B^{0} \rightarrow π^{0} π^{0}$ and $B^{\pm} \rightarrow K^{+} K^{-} π^{\pm}$. The $B^{0} \rightarrow π^{0} π^{0}$ measurements enable us to improve constraints on the angle $ϕ_{2}$ of the CKM unitarity triangle. For $B^{\pm} \rightarrow K^{+} K^{-} π^{\pm}$ we measure $CP$ asymmetry as a function of the invariant…
The measurement of time-dependent CP asymmetries in charm decays can provide a unique insight into the flavor changing structure of the Standard Model. We examine a number of different CP eigenstate decays of D mesons and describe a method that can be used to measure time-dependent CP asymmetries at existing and future experiments, with a preliminary assessment, based on statistical considerations, of their various capabilities. Any asymmetry observed in time-dependent analysis of neutral D mesons could signify new physics. We discuss the measurements required to perform direct and indirect te…
With the experimental evidences of $\overline B {}^0\to p \overline{p}$ and $B^-\toΛ\overline p$ decays, it is now possible to extract both tree and penguin amplitudes of the charmless two-body baryonic $B$ decays for the first time. The extracted penguin-tree ratio agrees with the expectation. Using the topological amplitude approach with the experimental results on $\overline B {}^0\to p \overline{p}$ and $B^-\toΛ\bar p$ decay rates as input, predictions on all other $\overline B_q\to {\cal B} \overline {\cal B}$, ${\cal B} \overline {\cal D}$, ${\cal D} \overline {\cal B}$ and ${\cal D} \ov…
We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb-1 of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, A_CP(BsKpi) = +0.39 +- 0.15 stat +- 0.08 syst, and bottom baryons, A_CP(Lb->ppi) = +0.03 +- 0.17 stat +- 0.05 syst and A_CP(Lb->pK) = +0.37 +- 0.17 +- 0.03 syst. In addition, we measure CP violation in Bd-->Kpi decays with 3.5sigma significance, A_CP(B->…
Some years ago, a method was proposed for measuring the CP-violating phase gamma using pairs of two-body decays that are related by U-spin reflection (d <-> s). In this paper we adapt this method to charmless B -> PPP decays. Time-dependent Dalitz-plot analyses of these three-body decays are required for the measurement of the mixing-induced CP asymmetries. However, isobar analyses of the decay amplitudes are not necessary. A potential advantage of using three-body decays is that the effects of U-spin breaking may be reduced by averaging over the Dalitz plot. This can be tested independently u…
The gluon polarisation in the nucleon has been determined by detecting charm production via D0 meson decay to charged K and pi in polarised muon scattering off a longitudinally polarised deuteron target. The data were taken by the COMPASS Collaboration at CERN between 2002 and 2006 and corresponds to an integrated luminosity of 2.8 fb^-1. The dominant underlying process of charm production is the photon-gluon fusion to a cc-bar pair. A leading order QCD approach gives an average gluon polarisation of (Delta g/g)_x= -0.49 +- 0.27(stat) +- 0.11(syst) at a scale mu^2 ~ 13 (GeV/c)^2 and at an aver…
We perform a comprehensive SU(3)-flavor analysis of charmed mesons decaying to two pseudoscalar SU(3)-octet mesons. Taking into account SU(3)-breaking effects induced by the splitting of the quark masses, m_s != m_{u,d}, we find that existing data can be described by SU(3)-breaking of the order 30%. The requisite penguin enhancement to accomodate all data on CP violation tends to be even larger than the one extracted from Delta a_{CP}^{dir}(K^+K^-,pi^+pi^-) alone, strengthening explanations beyond the standard model. Despite the large number of matrix elements, correlations between CP asymmetr…
The LHCb experiment is capable of studying four-body decays of the $b$-flavored baryons $Λ_b$ and $Ξ_b^0$ to charmless final states consisting of charged pions, kaons, and baryons. We remark on the search in such modes for CP-violating triple product asymmetries and for CP rate asymmetries relative to decays involving charmed baryons.
With a sample of approximately 89 million BBbar pairs collected with the BABAR detector, we measure branching fractions, determine the degree of longitudinal polarization, and search for direct CP violation in the decays B0=>phiK*0 and B+=>phiK*+. We perform a search for other charmless vector-vector B decays involving rho and K*(892) resonances and observe the decays B+=>rho0K*+ and B+=>rho0rho+. The branching fractions are measured to be BR(phiK*0)=(11.1^{+1.3}_{-1.2}\pm 1.1)10^{-6}, BR(phiK*+)=(12.1^{+2.1}_{-1.9}\pm 1.5)10^{-6}, BR(rho0K*+)=(7.7^{+2.1}_{-2.0}\pm 1.4)10^{-6}, and BR(rho0rho+…
We present measurements of branching fractions and \CP-violating asymmetries in decays of $B$ mesons to two-body final states containing a \Kz. The results are based on a data sample of approximately 88 million \upsbb decays collected with the \babar detector at the \pep2 asymmetric-energy $B$ Factory at SLAC. We measure $\BR(\Bp\to\Kz\pip) = (22.3 \pm 1.7 \pm 1.1)\times 10^{-6}$, $\BR(\Bz\to\Kz\piz) = (11.4\pm 1.7\pm 0.8)\times 10^{-6}$, $\BR(\Bp\to\Kzb\Kp) < 2.5\times 10^{-6}$, and $\BR(\Bz\to\KzKzb) < 1.8\times 10^{-6}$, where the first uncertainty is statistical and the second is systemati…
We present measurements of the branching fractions and a search for CP-violating charge asymmetries in charmless hadronic decays of B mesons into two-body final states of kaons and pions. The results are based on a data sample of approximately 23 million BB(bar) pairs collected by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. We find the following branching fractions: BF(B0-->pi+pi-)= (4.1+/-1.0+/-0.7) x 10^{-6}, BF(B0-->K+pi-)=(16.7+/-1.6+/-1.3) x 10^{-6}, BF(B+-->K+pi0)=(10.8^{+2.1}_{-1.9}+/-1.0) x 10^{-6}, BF(B+-->K0pi+)=(18.2^{+3.3}_{-3.0}+/-2.0) x 10^{-6}, BF(B0-->K0pi0)=…
We present CDF results on the branching fractions and time-integrated direct CP asymmetries for Bd, Bs and Lb decay modes into pairs of charmless charged hadrons (pions, kaons and protons). The data-set for these measurements amounts to 1fb^{-1} of pbar-p collisions at a center of mass energy 1.96TeV. We report on the first observation of the Bs->Kpi, Lb-ppi and Lb->pK decay modes and on the measurement of their branching fractions and direct CP asymmetries.
Recent evidence for direct CP violation in non-leptonic charm decays cannot be easily accommodated within the Standard Model (SM). On the other hand, it fits well in new physics models generating CP violating Delta C=1 chromomagnetic dipole operators. We show that in these frameworks sizable direct CP asymmetries in radiative D to P+ P- gamma decays (P=pi,K), with M_PP close to the rho or the phi peak, can be expected. Enhanced matrix elements of the electromagnetic dipole operators can partly compensate the long distance dominance in these decays, leading to CP asymmetries of the order of sev…
A doubly CKM-suppressed amplitude in $B^0\to J/ψK_S$ leads to corrections in CP asymmetries $S = \sin 2β, C=0$, which may be enhanced by long-distance rescattering. It has been suggested that this enhancement may lead to several percent corrections. We calculate an upper bound of order $10^{-3}$ on rescattering corrections using measured branching ratios for charmless $|ΔS|=1$ $B^0$ decays.
We study the branching ratios and up-down asymmetries in the charmed baryon weak decays of ${\bf B}_c\to {\bf B}_DM$ with ${\bf B}_{c(D)}$ anti-triplet charmed (decuplet) baryon and $M$ pseudo-scalar meson states based on the flavor symmetry of $SU(3)_F$. We propose equal and physical-mass schemes for the hadronic states to deal with the large variations of the decuplet baryon momenta in the decays in order to fit with the current experimental data. We find that our fitting results of ${\cal B}({\bf B}_c\to {\bf B}_DM) $ are consistent with the current experimental data in both schemes, while …
Various new measurements in charmless $B_{u,d,s}\to PP$ modes, where $P$ is a low lying pseudoscalar meson, are reported by Belle and LHCb. These include the rates of $B^0\toπ^0π^0$, $ηπ^0$, $B_s\toη'η'$, $B^0\to K^+K^-$ and $B^0_s\toπ^+π^-$ decays. Some of these modes are highly suppressed and are among the rarest $B$ decays. Direct CP asymmetries on various modes are constantly updated. It is well known that direct CP asymmetries and rates of suppressed modes are sensitive to final state interaction (FSI). As new measurements are reported and more data will be collected, it is interesting an…
We study the final-state interaction (FSI) effects in charmless B_{u,d,s} to PP decays. We consider a FSI approach with both short- and long-distance contributions, where the former are from in-elastic channels and are contained in factorization amplitudes, while the latter are from the residual rescattering among PP states. Flavor SU(3) symmetry is used to constrain the residual rescattering S-matrix. We fit to all available data on the CP-averaged decay rates and CP asymmetries, and make predictions on unmeasured ones. Our main results are as follows: (i) Results are in agreement with data i…
Semileptonic Flavor Changing Neutral Current decays of charmed hadrons uniquely probe the up-sector of the Standard Model. Clean null test observables, such as CP-asymmetries, lepton-universality ratios, missing energy modes, lepton flavor violating modes and angular observables can be studied in a variety of charmed meson and baryon modes. An overview of null test opportunities with rare charm decays is presented and similarities and complementarities of different modes are worked out.
Using data collected by LHCb experiment in 2011 we report the measurements of charge asymmetries in charmless decays of B mesons in two or three charged kaons or pions. We find positive charge asymmetries in the channels Bs->K-pi+(3.3 sigmas), B+->K+pi+pi- (2.8 sigmas), and B+->pi+pi+pi- (4.2 sigmas) and negative in B0->K+pi-(6 sigmas),B+->K+K+K- (3.7 sigma), B+->K+K-pi+ (3.0 sigma).
The discrete symmetries C, P and CP are known to be violated by the weak interaction. It is possible to probe the breaking of these symmetries using asymmetries constructed from triple products based on the decay of some particle M to a four body final state. These proceedings discuss the full set of possible asymmetries that can be probed and applications to various measurement scenarios, focusing mostly on charm mesons and baryons. The ramifications of what can be learned from such measurements are also discussed.
We introduce a set of observables representing angular distribution asymmetries, which can be viewed as a generalization of the forward-backward asymmetry of angular distributions, and can be used as an effective tool to search for $C\!P$ violation in three-body decays of bottom and charmed baryons. We propose to search for such $C\!P$ asymmetries (1) in decays with $Λ^0$, $Σ^\pm$, or $Λ_c^+$ involved, such as $Λ_b\to Λ^0 D$ and $Λ_b\toΛ^0ρ(770)^0$; and (2) in three-body decays of bottom baryons with opposite parity intermediate resonances involved. Typical examples include $Ξ_b^-\to p K^- K^-…
We report on measurements of time-dependent CP-violation asymmetries in neutral B meson decays to charmonium and charm final states. The results are obtained from a data sample of 467+/-5 million Y(4S)->BBbar decays collected with the BaBar detector at the PEP-II B factory.
Relative branching fractions of B^0_d,s -> h^+ h^'- decays (where h, h' = K or pi) and the direct CP asymmetry A_CP in the B^0_d -> K^+ pi^- mode are measured with 179 +- 11 pb^-1 of data collected at sqrt{s} = 1.96 TeV using the CDF II detector at the Fermilab Tevatron ppbar collider. The first branching-fraction measurement of a B^0_s meson to two pseudoscalars, Br(B^0_s -> K^+ K^-), and a search for the baryon mode Lambda^0_b -> p^+ h^- are also presented, in addition to branching-fraction limits on the rare channels B^0_s -> K^+ pi^-, B^0_d -> K^+ K^-, and B^0_s -> pi^+ pi^-.
Triple product asymmetries have been used to probe CP violation in $K$, $D$, and B decays. Here we review the interpretation of those asymmetries, and note that it is possible to construct twelve measurable triple product asymmetries for the decay of a particle into a four body final state. Eight of these asymmetries are introduced here and nine have never been measured before. These can be used to systematically test C, P, and CP symmetries in decays to four body final states. In particular we note that these asymmetries can be used to study symmetry invariance in Higgs, $Z^0$, top-quark, and…
U-spin symmetry predicts equal CP rate asymmetries with opposite signs in pairs of $ΔS=0$ and $ΔS=1$ $B$ meson decays in which initial and final states are related by U-spin reflection. Of particular interest are six decay modes to final states with pairs of charged pions or kaons, including $B_s \to π^+K^-$ and $B_s\to K^+K^-$ for which asymmetries have been reported recently by the LHCb collaboration. After reviewing the current status of these predictions, highlighted by the precision of a relation between asymmetries in $B_s \to π^+K^-$ and $B^0\to K^+π^-$, we perform a perturbative study …
