C. Q. Geng, Y. K. Hsiao
We review the direct CP and T violation in the three-body baryonic B decays in the standard model. In particular, we emphasize that the direct CP violating asymmetry in $B^\pm\to p\bar p K^{*\pm}$ is around 22% and the direct $T$ violating asymmetry in $\bar B^0 \ra Λ\bar p π^+$ can be as large as 12%, which are accessible to the current B factories at KEK and SLAC as well as SuperB and LHCb.
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We study $T$ violation in the three-body charmless baryonic decay of $\bar B^0 \ra Λ\bar p π^+$ through the $T$-odd triple product correlation in the standard model. We find that the $T$ violating asymmetry is 10%, which is accessible to the current B factories at KEK and SLAC, while the CP violating one 1.1%. We emphasize that this triple product correlation would be the first measurable direct $T$ violating effect predicted in the standard model.
Supersymmetric scenarios with R-parity conservation are becoming very constrained due to the lack of missing energy signals, thus motivating those scenarios with R-parity violation. In view of this, we consider a supersymmetric model with R-parity violation and extended by an anomalous horizontal $U(1)_H$ symmetry, where a self-consistent framework with baryon-number violation is achieved along with a proper supression for lepton number violating dimension-5 operators in order to keep a proton decay safe. With the introduction of right-handed neutrinos both Dirac and Majorana masses can be acc…
We investigate the possibility of obtaining sizeable R-parity breaking interactions violating baryon number but not lepton number within supersymmetric grand unified theories. Such a possibility allows to ameliorate the naturalness status of supersymmetry while maintaining successful gauge coupling unification, one of its main phenomenological motivations. We show that this can be achieved without fine-tuning or the need of large representations in simple SO(10) models.
Baryonic R-parity violation arises naturally once Minimal Flavor Violation (MFV) is imposed on the supersymmetric flavor sector at the low scale. At the same time, the yet unknown flavor dynamics behind MFV could take place at a very high scale. In this paper, we analyze the renormalization group (RG) evolution of this scenario. We find that low-scale MFV is systematically reinforced through the evolution, with the R-parity violating couplings exhibiting infrared fixed points. Intriguingly, we also find that if holomorphy is imposed on MFV at some scale, it is preserved by the RG evolution. Fu…
We discuss a possibility that baryon number $B$ is spontaneously broken at low scales, of the order of MeV or even smaller, so that the neutron-antineutron oscillation can be induced at the experimentally accessible level. An associated Goldstone particle, baryonic majoron, can have observable effects in neutron to antineutron transitions in nuclei or dense nuclear matter. By extending baryon number to $B-L$ symmetry, baryo-majoron can be identified with the ordinary majoron associated with the spontaneous breaking of lepton number, with interesting implications for neutrinoless $2β$ becay wit…
Lepton flavour violation (LFV) naturally occurs in many new physics models, specifically in those explaining the $B$ anomalies. While LFV has already been studied for mesonic decays, it is important to consider also baryonic decays mediated by the same quark transition. In this paper, we study LFV in the baryonic $Λ_b \to Λ\ell_1 \ell_2$ using for the first time a full basis of New Physics operators. We present expected bounds on the branching ratio in a model-independent framework and using two specific new physics models. Finally, we point out the interplay and orthogonality between the bary…
We point out that if the baryon number violating neutron-antineutron oscillation is discovered, it would impose strong limits on the departure from Einstein's equivalence principle at a level of one part in $10^{19}$. If this departure owes its origin to the existence of long-range forces coupled to baryon number $B$ (or $B-L$), it would imply very stringent constraints on the strength of gauge bosons coupling to baryon number current. For instance, if the force mediating baryon number has strength $α_B$ and its range is larger than a megaparsec, we find the limit to be $α_B \leq 2\times 10^{-…
In the scenario of cold electroweak baryogenesis, oscillations of the Higgs field lead to metastable domains of unbroken phase where the Higgs field nearly vanishes. Those domains have also been identified with the $W-t-\bar{t}$ bags, a non-topological soliton made of large number ($\sim 1000$) of gauge quanta and heavy (top and anti-top) quarks. As real-time numerical studies had shown, sphalerons (topological transition events violating the baryon number) occur only inside those bags. In this work we estimate the amount of CP violation in this scenario coming from the Standard Model, via the…
The physics of electroweak baryogenesis is described with the aim of making the essentials clear to non-experts. Several models for the source of the necessary CP violation are discussed: CKM phases as in the minimal standard model, general two higgs doublet models, the supersymmetric standard model, $Z$ condensates, and the singlet majoron model. In a more technical section, a strategy is introduced for consistently treating quark dynamics in the neighborhood of the bubble wall, where both local and non-local interactions are important. This provides a method for deciding whether gluonic corr…
We study the T violating effects in the baryonic decays of $Λ_b\toΛl^+l^- (l=e ,μ)$ with polarized $Λ$. We show that the transverse $Λ$ polarizations in these baryonic decays could be as large as 50% in CP violating theories beyond the standard model such as the SUSY models, which can be tested in various future hadron colliders.
We study the two-body baryonic $B$ and $D_s$ decays based on the annihilation mechanism without the partial conservation of axial-vector current (PCAC) at the GeV scale. We demonstrate that the contributions of $B^-\to Λ\bar p$, $B^-\to Σ^0 \bar p$ and $\bar B^0_s\to Λ\bar Λ$ are mainly from the scalar and pseudoscalar currents with their branching ratios predicted to be around $(3.5,\,5.3,\,5.3)\times 10^{-8}$, respectively, exactly the sizes of ${\cal B}(B\to {\bf B\bar B'})$ established by the data. We also apply the annihilation mechanism to all of the charmless two-body baryonic $B$ and $…
The observation of CP violation has been experimentally verified in numerous $B$ decays but is yet to be confirmed in final states with half-spin particles. We focus our attention on baryonic $B$-meson decays mediated dominantly through internal $W$-emission processes and show that they are promising processes to observe for the first time the CP violating effects in $B$ decays to final states with half-spin particles. Specifically, we study the $\bar B^0\to p\bar pπ^0(ρ^0)$ and $\bar B^0\to p\bar pπ^+π^-$ decays. We obtain ${\cal B}(\bar B^0\to p\bar pπ^0)=(5.0\pm 2.1)\times 10^{-7}$, in agre…
The LHCb collaboration has presented first experimental evidence that spin-carrying matter and antimatter differ. The study looked at four-body decays of the $Λ_b^0$ baryon. Differences in the behaviour of matter and antimatter are associated with the non-invariance of fundamental interactions under the combined charge-conjugation and parity transformations, known as $C\!P$ violation. We discuss purely baryonic decay processes, i.e. decay processes involving only spin-carrying particles. They are yet unexplored elementary processes. Their study opens a new chapter of flavour physics in the rou…
Purely Baryonic Weak Decays of Heavy Baryons in Skyrme Model
本文基于Skyrme模型研究重子纯弱衰变，探讨其作为测试标准模型的新通道，计算Λ_b→p\ar p n衰变分支比为10^-6量级。
We point out new ways to search for charmless baryonic B decays: baryon pair production in association with $η^\prime$ is very likely as large as or even a bit larger than two body $Kπ/ππ$ modes. We extend our argument, in weaker form, to $B\to γ+ X_s$ and $\ellν+X$. Although calculations are not reliable, estimates give branching ratios of order $10^{-5}$--$10^{-6}$, where confidence is gained from recent experimental finding that $B \to D^{*} p \bar n$, $D^{*} p \bar p π$ are not far below $D^*π$ and $D^*ρ$ rates. Observation of charmless baryon modes would help clarify the dynamics of weak …
We explore the possibility of CP violation in baryonic $Λ_b\to(Λ_c^+, p^+)π^+μ^-μ^-$ decays which are mediated by two Majorana sterile neutrino and are $|ΔL|=2$ lepton number violating processes. Appreciable CP asymmetry can be obtained if there are two on-shell Majorana neutrinos that are quasi-degenerate in mass with the mass difference of the order of average decay widths. We find that given the present constraints on the heavy to light mixing element $|V_{μN}|$, the $Λ_b\to p^+π^+μ^-μ^-$ and $Λ_b\to Λ_c^+π^+μ^-μ^-$ decay rates are suppressed but could be within the experimental reach at th…
We examine the T-odd transverse lepton and $Λ$ polarizations in the baryonic decays of $Λ_b\toΛl^+l^- (l=e ,μ)$ to study the T violating effects. We show that the lepton polarizations are suppressed but the $Λ$ ones can be as large as 50% in CP violating theories beyond the standard model such as the SUSY models, which can be tested in various future hadron colliders.
We study the discovery reach of the gluino ($\widetilde{g}$) and the lightest stop squark ($\widetilde{t}_1$) with baryonic R-parity violation (UDD type) in the context of Minimal Supersymmetric Standard Model (MSSM) at the 14 TeV run of the LHC. We consider the gluino pair production process followed by its decay to a top quark and a real or virtual stop squark. The top quark produced from the decay of the gluino can have sufficient transverse momentum to appear as a single fat jet. We apply the jet substructure technique to tag such a hadronically decaying boosted top quark and find that glu…
Constraining anti-baryonic dark matter through correlated nucleon decay signatures
本文研究反重子暗物质诱发的重子数破缺，通过关联单中子与双核子衰变过程，利用二者对暗物质密度依赖的差异，联合约束反重子暗物质的局域密度与质量。
We study the rates and direct CP violations of two-body baryonic $\bar B_{u,d,s}\to {{\rm\bf B}\overline{\rm\bf B}}'$ and $B^-_c\to{{\rm\bf B}\overline{\rm\bf B}}'$ decays, where the final state baryons include low-lying octet and decuplet baryons. We incorporate topological amplitude formalism and the factorization approach. Asymptotic relations at large $m_b$ are used to simplify decay amplitudes. Using the most up-to-date data on $\bar B^0\to p\bar p$ and $B^-\toΛ\bar p$ decay rates as inputs, rates and direct CP violations of $\bar B_{u,d,s}\to {{\rm\bf B}\overline{\rm\bf B}}'$ decays are …
We investigate the exclusive rare baryonic $Λ_{b}\toΛ\ell^{+}\ell^{-}$ in a family non-universal $Z^{\prime}$ model, which is one of the natural extension of standard model. Using transition form factors, calculated in the framework of light cone QCD sum rules, we analyze the effects of polarized and unpolarized CP violation asymmetries for the said decay. Our results indicate that the value of unpolarized and polarized CP-violation asymmetries are considerable in both $Λ_{b}\toΛμ^{+}μ^{-}$ and $Λ_{b}\toΛτ^{+}τ^{-}$ channels and hence they give clear indication of new physics arising from the …
Searching for long-lived light neutralinos from $B$-meson decays with baryonic R-parity violation at Belle II
本文提出面向 Belle II 的部分重建与位移顶点分析方法，以探测重子数 RPV 下 B 介子衰变产生的长寿命 GeV 级中性微子，并证明其可显著超越现有耦合限制。
We study the direct CP violation in $B^\pm\to p\bar p K^{(*)\pm}$ decays in the standard model. We point out that these three-body baryonic B decays can be important tools for detecting the direct CP violation in the charged $B$ system, in which there are no conclusive signatures yet. In particular, we show that the direct CP violating asymmetry in $B^\pm\to p\bar p K^{*\pm}$ is around 22% which supports the recent data by the BABAR Collaboration.
The combination Charge Conjugation-Parity-Time Reversal(CPT) is a fundamental symmetry in our current understanding of nature. As such, testing CPT violation is a strongly motivated path to explore new physics. In this paper we study CPT violation in the neutrino sector, giving for the first time a bound, for a fundamental particle, in the CPT violating particle-antiparticle gravitational mass difference. We argue that cosmology is nowadays the only data sensitive to CPT violation for the neutrino-antineutrino mass splitting and we use the latest data release from Planck combined with the curr…
Possible large CP violation in charmed $Λ_b$ decays
本文提出利用 $Λ_b$ 的含粲级联衰变探测重子 CP 破坏，通过 $D^0$ 与 $\ar{D}^0$ 振幅间的大弱相位获得显著不对称性，并论证其在 LHCb 上的发现潜力。
On the origin of CP symmetry violations
本文提出地球引力通过耦合味振荡与夸克zitterbewegung振荡诱导CP本征态叠加，从而解释CP破缺的物理起源，并预言三个破缺参数与实验一致，且破缺幅度与引力线性相关，为宇宙重子不对称性提供新机制。
Impact of $N^*$ and $Λ^*$ resonances on $CP$ violation in $Λ_b^0$ decays
基于组分夸克模型，识别出激发核子和超子共振态对四体衰变 $\Lambda_b^0\to pK^-\pi^+\pi^-$ 的贡献，计算得到分支比和 $CP$ 不对称性，首次建立了量化激发重子共振态在多体 beauty-重子衰变中影响的框架。
We consider interactions of fermions with the domain wall bubbles produced during a first order phase transition. A new exact solution of the Dirac equations is obtained for a wall profile incorporating a position dependent CP violating phase. The reflection coefficients are computed, a resonance effect is uncovered for rapidly varying phases. This resonance effect happens when the energy and mass of the incident particles are $E/m=Δθ/2$. Where $Δθ$ is the phase variation across the wall width. We calculate the chiral charge flux through the wall surface and the corresponding baryon asymmetry …
We study CP violation in b-baryon decays of $Ξ_b^- \to Ξ^- D$ with $D = D^0, \bar{D}^0$ and $D_i~(i=1,2)$. We find that these baryonic decay processes provide an ideal opportunity to measure the weak phase due to the absence of the relative strong phase. Explicitly, we relate $\barρ$ and $\barη$ the CKM elements with the decay rate ratios of $R_i= Γ(Ξ_b^- \to Ξ^-D_{i} ) / Γ( Ξ_b^- \to Ξ^-D^0 )$ without the charge conjugate states. As a complementary, we also examine the decay distributions of $Λ_b \to Λ(\to p π^- ) D$. There are in total 32 decay observables, which can be parameterized by 9 re…
Evidence for CP violation in baryonic decays has not been seen in experiments. With large data events accumulated at $e^+e^-$ collider or Large Hadron Collider, the charmed baryon decays would provide a promising laboratory to test the CP symmetry. In this work, we formulate the $Λ_c^+\toϕp$ and $ Λ_c^+\toωp$ decays for the measurements of their asymmetry parameters in weak decays at the BESIII or the LHCb experiments. The polarization transfer is analyzed in the two processes of $e^+ e^- \toΛ_c^+\barΛ_c^-$ and $Λ_b^0\to Λ^+_cπ^-$, and the formulas of the joint angular distribution for these p…
We study for the first time the three-body charmless baryonic decays $\bar B^0_s\to \bar p ΛM^+ (p \bar ΛM^-)$, with $M=π, K$. We find that the branching ratios of $\bar B^0_s\to (\bar p ΛK^+$ and $p\bar ΛK^-)$ and $\bar B^0_s\to p\bar Λπ^-$ are $(5.1\pm 1.1)\times 10^{-6}$ and $(2.8\pm 1.5)\times 10^{-7}$, respectively, which agree with recent experimental results reported by the LHCb collaboration. In addition, we derive the relations \mbox{${\cal B}(\bar B^0_s\to \bar p ΛK^+)\simeq (f_K/f_π)^2(τ_{B^0_s}/τ_{B^0}) {\cal B}(\bar B^0\to \bar p Λπ^+)$} and ${\cal B}(\bar B^0_s\to p\bar Λπ^-)/{\c…
We investigate the connection between R-parity violation (RPV) in supersymmetric models and Baryogenesis. First we discuss in detail the assumptions of a theorem by Nanopoulos and Weinberg on the CP asymmetry generated from the decay of massive particles. In light of this statement, we analyse some interesting models of Baryogenesis through RPV. We then explore, in the context of RPV SUSY, the possibility to generate the baryon asymmetry through the out-of-equilibrium decay of a metastable Weakly Interacting Massive Particle (WIMP), as proposed in \cite{Cui:2012jh}. This setting is also motiva…
Baryonic R-parity violation could explain why low-scale supersymmetry has not yet been discovered at colliders: sparticles would be hidden in the intense hadronic activity. However, if the known flavor structures are any guide, the largest baryon number violating couplings are those involving the top/stop, so a copious production of same-sign top-quark pairs is in principle possible. Such a signal, with its low irreducible background and efficient identification through same-sign dileptons, provides us with tell-tale signs of baryon number violating supersymmetry. Interestingly, this statement…
The possible existence of light and heavy sterile neutrinos may give rise to direct and indirect unitarity violation of the $3\times3$ lepton mixing matrix respectively. In the current work we study the potential of future accelerator neutrino facilities in probing the unitarity violation effects. Taking DUNE, T2HK and a low-energy Neutrino Factory (LENF) as working examples of future accelerator neutrino facilities, we study the distinct effects of direct and indirect unitarity violation on the discovery reach of the leptonic CP violation and precision measurements of $θ_{23}$ in the three ne…
A large number of observables can be constructed from differential decay rate based on the polarization of final state while considering decay of a neutral meson $(P^0 \text{ or } \bar P^0)$ to two vector particles. But all of these observables are not independent to each other since there are only a few independent theoretical parameters controlling the whole dynamics and therefore various relations among observables emerge. In this paper, we have studied the behaviour of observables for neutral meson decaying to two vectors in presence of T and CPT violations in mixing accompanied by both di…
Reference to recent papers and experimental feasibility are added. The paper will not be published in a hard-copy journal.
A Discovery Voyage into The Age of: PENGUINS (chubby little figure).
We discuss the perspectives of measuring direct CP violation parameters in hyperon decays by measurements with proton and/or antiproton beams, to be carried out at various facilities, and in particular we propose new experiments at the Tevatron and at the LHC.
I formulate expressions for amplitudes suitable for quantifying both modulus and phase direct CP violations. They result in Möbius transformation (MT) relations, which provide encouraging information for the search of direct CP violations in general. I apply the formulation to calculate the measurements of phase direct CP violations and strong amplitudes in $B^{\mp}\to K^{\mp}π^{\pm}π^{\mp}$ by the Belle collaboration. For the formulation, I show a versatile construction procedure for $N\times N$ Cabibbo-Kobayashi-Maskawa (CKM) matrices, Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrices, and gen…
We review different definitions of the $ε'$ parameter describing direct CP violation in neutral kaon decays, which was precisely measured in recent experiments, and point out the inconsistency of some of them due to a CPT constraint. The proper comparison of the experimental results to the theoretical computations is discussed.
We show that direct CP violation in semi-leptonic and leptonic decays can occur in multi-Higgs doublet extensions of the electroweak standard model with flavor changing neutral currents. For pion and lepton decays these $CP$ violating effects cannot be constrained directly by experimental data since up to now the branching ratio of the decays $π^-$ and $μ^-$ have not been measured in laboratory.
Currently there are New Physics hints in mixing-induced CP violation S(phi K0), S(pi0 K0) < S(J/psi K0), unequal direct CP violation A(K+ pi-) differs A(K+ pi0), and maybe even in measured S(J/psi K0) vs prediction from global fit to other data. However, these hints either suffer from experimental uncertainties, or uncertain hadronic corrections, and are not yet unequivocal. Motivated by these hints, however, we point out that a unique probe may be direct CP violation in B to JψK mode. An asymmetry observed at 1% or higher would indicate New Physics.
We investigate the implications of direct CP violation (CPV) on the determination of the unitarity triangle angle γ from B -> DK decays. We show that γ can still be extracted even with the inclusion of direct CPV in charm if (i) at least one of the D decays has negligible CP violation; and (ii) data from charm factory at threshold are used. If approximate expressions without including direct CP violation in charm are used, this can result in a shift in γ that is O(r_D/r_B). It is modest for B -> DK but can be O(1) for B -> Dπ. We illustrate the size of the shift on an example of Gronau-London-…
The most general Two Higgs Doublet Model (2HDM) allows both for the explicit and the spontaneous CP violation in the scalar sector. Here we discuss CP violation in terms of basis-independent quantities and show how using two different sets of known CP-odd weak-basis invariants one can distinguish between CP conservation, explicit CP violation and spontaneous CP violation. The special case of CP violation without CP mixing, in which the neutral Higgs gauge boson interaction respects CP while Higgs self-interaction violates CP symmetry, is also presented.
Based on $ψ(3686)$ decays of 106 million, the 1.31 billion J/psi events and a data sample of $ψ(3770)$ with $2.9~fb^{-1}$ integrated luminosity, many analyses are performed. Exclusively baryonic decays of the $ψ(3770)$, the radiative transition $ψ(3770)\toγη_c(2S)$, the $ψ(3770)$ transition to $χ_{cJ}$, isospin violation decay $χ_{c0,2}\toπ^0η_c$, the $C-$parity violation decays $J/ψ\toγγ,γϕ$ are searched for, but no significant signals are observed, and upper limits are set for these decays. The decays of $ψ(3770)\toγχ_{c1}$ and $J/ψ\toπ^0ϕ$ signals are observed. These measurements provide mo…
Lifting Effective-Field-Theory Degeneracies in Semileptonic Heavy-Baryon Decays
利用格点QCD螺旋度形状因子分析Λ_b→Λ_cτν̄_τ等重子衰变，发现τ极化是区分当前R(D)和R(D^*)测量中未解决的有效场论简并性的关键，标量型新物理会产生大的极化偏移和低q^2谱形变。
In perturbative QCD approach, we study the direct $CP$ violation in the decay of $\bar{B}_s^0\toρ(ω)ϕ\to {π^+}{π^-}ϕ$ via isospin symmetry breaking. An interesting mechanism involving the charge symmetry violating between $ρ$ and $ω$ is applied to enlarge the $CP$ violating asymmetry. We find that the $CP$ violation can be enhanced by the $ρ-ω$ mixing mechanism when the invariant masses of the $π^+π^-$ pairs are in the vicinity of the $ω$ resonance. For the decay process of $\bar{B}^0_{s}\toρ(ω)ϕ\to{π^+}{π^-}ϕ$, the maximum $CP$ violation can reach $5.98\%$. The possibility of detecting the $C…
The recently observed direct CP violation in $B_d \to K^+ π^-$ has raised suggestions of possible new physics. A robust test of the standard model vs. new physics is its prediction of equal direct CP violation in $B_s \to K^- π^+$ decay. CPT invariance requires the observed CP violation to arise from the interference between the dominant penguin amplitude and another amplitude with a different weak phase and a different strong phase. The penguin contribution to $B_d \to K^+ π^-$ is known to be reduced by a CKM factor in $B_s \to K^- π^+$. Thus the two branching ratios are very different and a …
The NA48 experiment at the CERN SPS aims to search for direct CP violation in the $K^0$ system through the measurement of ${\rm Re}(ε'/ ε)$ with high accuracy. In 1999 the NA48 collaboration has published its first measuremen based on 1997 data. A new result, based on 1998 and 1999 data, is presented in this article. The result, combined with 1997 data, ${\rm Re}(ε'/ε) = (15.3 \pm 2.6)\times 10^{-4}$, contributes to the precise determination of the size of direct CP violation.
Minimal Flavor Violation in the up-type quark sector leads to particularly interesting phenomenology due to the interplay of flavor physics in the charm sector and collider physics from flavor changing processes in the top sector. We study the most general operators that can affect top quark properties and $D$ meson decays in this scenario, concentrating on two CP violating operators for detailed studies. The consequences of these effective operators on charm and top flavor changing processes are generically small, but can be enhanced if there exists a light flavor mediator that is a Standard …
We investigate the direct $CP$ violation for the decay process of $\bar{B}_{s}\rightarrow P(V)π^{0}$ (P,V refer to the pseudoscalar meson and vector meson, respectively) via isospin symmetry breaking effects from the $π^{0}-η-η'$ mixing mechanism in PQCD factorization approach. Isospin symmetry breaking arises from the electroweak interaction and the u-d quark mass difference by the strong interaction which are known to be tiny. However, we find that isospin symmetry breaking at the leading order shifts the $CP$ violation due to the new strong phases.
Direct CP violation can exist in untagged, neutral B-meson decays to certain self-conjugate, hadronic final states. It can occur if the resonances which appear therein permit the identification of distinct, CP-conjugate states -- in analogy to stereochemistry, we term such states ``CP-enantiomers.'' These states permit the construction of a CP-odd amplitude combination in the untagged decay rate, which is non-zero if direct CP violation is present. The decay B\to π^+π^-π^0, containing the distinct CP-conjugate states ρ^+ π^- and ρ^- π^+, provides one such example of a CP-enantiomeric pair. We …
Supersymmetric extensions of the Standard Model predict a large enhancement of the Wilson coefficients of the dimension-five electromagnetic penguin operators affecting the direct CP violation in K_L --> pi^0 e^+ e^- and the charge asymmetry in K^\pm --> pi^\pm l^+ l^-. Here we compute the relevant matrix elements in the chiral quark model and compare these with the ones given by lattice calculations
CP violation due to interference between $K_L$ and $K_S$ decays into $π^+π^-γ$ is analyzed in the Standard Model. The CP-violating parameter $ε'_{+- γ}$, which is the difference between $η_{+-γ}$ and $η_{+-}$, receives dominant contributions from $K^0-\bar{K}^0$ mixing and the gluon penguin diagram; its magnitude is calculated to be $10^{-2}ε$ at a typical region of the Dalitz plot. Genuine direct CP violation in $K_L\toπ^+ π^-γ$ decay originating from the electromagnetic penguin diagram is of order $10^{-4}ε$.
We have investigated the effects of unparticles in decays $B \to l ν$. It is found that the direct CP violation in the decays, which is zero in SM, can show up due to the CP conserving phase intrinsic in unparticle physics. For $l=τ$, the direct CP asymmetry can reach 30% for the scalar unparticle contribution, and 100% for the longitudinal vector unparticle contribution under the constraints of ${\rm Br}(B\toτν)$ and $νe$ elastic scattering. If both unparticle-lepton coupling universality and unparticle-quark coupling universality are assumed the constraint from $Br(π\to μν)$ leads that the d…
Weak radiative baryonic B decays $\bar B\to B_1\bar B_2γ$ mediated by the electromagnetic penguin process $b\to sγ$ are re-examined within the framework of the pole model. The meson pole contribution that has been neglected before is taken into account in this work. It is found that the intermediate $K^*$ contribution dominates in the $Σ\bar pγ$ mode and is comparable to the baryon pole effect in $Λ\bar pγ$ and $Ξ\barΛγ$ modes. The branching ratios for $B^-\toΛ\bar pγ$ and $B^-\toΞ^0\barΣ^-γ$ are of order $2.6\times 10^{-6}$ and $6\times 10^{-7}$, respectively. The threshold enhancement effect…
I review the implications of recent measurements of CP violation in D meson decays in the context of standard model extensions. Using effective theory methods, one can derive significant constraints on the possible non-standard contributions from measurements of neutral D meson mixing and direct CP violation in kaon decays. Due to an approximate universality of CP violation in new physics scenarios which only break the SU(3)_Q flavor symmetry of the standard model kinetic Lagrangian, such contributions are particularly constrained by epsilon'/epsilon. Explanations of the observed effect within…
We study the contribution of the squark flavor mixing from the $LR(RL)$ component of the squark mass matrices to the direct CP violation of the $b\to sγ$ decay and the CP-violating asymmetry in the non-leptonic decays of $B$ mesons. The magnitude of the $LR(RL)$ component is constrained by the branching ratio and the direct CP violation of $b\to sγ$. We predict the correlation of the CP asymmetries among $A_{\text{CP}}^{b \to s γ}$, $\mathcal{S}_{ϕK_S}$ and $\mathcal{S}_{η'K^0}$ of the B decays. The precise data of these CP violations will give us the crucial test for our framework of the squa…
We investigate the possibility of observing direct CP violation in self-tagging B-meson decays of the type b -> d J/ψ. The CP asymmetry can be generated due to strong or electromagnetic scattering in the final state, or due to long distance effects. The first two contributions give asymmetries of a few 10^(-3), in the standard model. The long distance effects are hard to estimate, but it cannot be excluded that they yield asymmetries of about 1%.
Using the generalized factorization approach, we calculate the CP asymmetries of charmless B decays. A number of decay channels has large CP asymmetries, which can be measured in the B factories.
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