Both BaBar and Belle have found evidence for a non-zero width difference in the $D^0$-$\bar D^0$ system. Although there is no direct experimental evidence for CP-violation in $D$ mixing (yet), we show that the measured values of the width difference $y\sim ΔΓ$ already imply constraints on the CP-violating phase in $D$ mixing, which, if significantly different from zero, would be an unambiguous signal of new physics.
We perform a theoretical study on direct $CP$ violation in $D^\pm\to π^\pm π^+π^-$ in phase space around the intermediate states $ρ^0(770)$ and $f_0(500)$. The possible interference between the amplitudes corresponding to the two resonances is taken into account, and the relative strong phase of the two amplitudes is treated as a free parameter. Our analysis shows that by properly chosen the strong phase, both the $CP$ violation strength and differential decay width accommodate to the experimental results.
We calculate the width difference of the scalar electron decay, $Γ(\tilde e_L \to e_Lω) - Γ({\bar{\tilde e}}_L \to \bar e_Lω)$ in the softly broken supersymmetrized standard model. The CP asymmetry is assumed to arise from the complex gaugino masses. Even in limit that the electron mass $m_e$ is vanishing, the difference can be of the order of $α$.
We investigate a possibility of observing CP asymmetries in the partial widths for the decays B^- -> pi^+ pi^- K^- and B^- -> K^+ K^- K^- produced by the interference of the non-resonant decay amplitude with the resonant amplitudes. The resonant states which subsequently decay into pi^+ pi^- and K^+ K^- or K^- pi^+ are charmonium c(bar) c states with J^P = 0^+, 1^-, 1^+ or the phi(1020) meson. We find that the largest partial width asymmetry comes from the chi_c0 resonance, while the resonances K^*_0(1430) and psi(2S) give a partial width asymmetry of the order 10%.
We discuss the effect of CP-violating $Zb\bar{b}$, $Zb\bar{b}G$ and $Zb\bar{b}γ$ couplings on the width $Γ(Z\rightarrow b\bar bX)$. The presence of such couplings leads in a natural way to an increase of this width relative to the prediction of the standard model. Various strategies of a direct search for such CP-violating couplings by using CP-odd observables are outlined. The number of $Z$ bosons required to obtain significant information on the couplings in this way is well within the reach of present LEP experiments.
We study the decay width and CP asymmetry of the inclusive process b--> s g (g denotes gluon) in the multi Higgs doublet models with complex Yukawa couplings, including next to leading QCD corrections. We analyse the dependencies of the decay width and CP asymmetry on the scale μand CP violating parameter θ. We observe that there exist an enhancement in the decay width and CP asymmetry is at the order of 10^{-2}.
We compute the width of the decay $h^0$ (125 GeV) $\to b \bar{b}$ at next-to-leading order in the general MSSM with quark-flavour violation (QFV). We study the effect of mixing between the second and the third generation of squarks, taking into account the constraints on QFV from B-meson data. We discuss the renormalisation of the process as well as the resummation of the bottom Yukawa coupling at large $\tan β$. We show numerical results on the decay width $Γ(h^0 \to b \bar{b})$ as a function of the involved QFV parameters and compare them with the corresponding width in the Standard Model.
In this article we give an overview of CP-violation for both K^0 (\bar{K}^0 ), B^0 (\bar{B}^0), and B_s(\bar{B}_s) systems. Direct CP-violation and mixing induced CP-violation are discussed for K^0(\bar{K}^0), and B^0(\bar{B}^0) decays.
We present an elementary derivation of the width of photon decay in a weak magnetic field using the semiclassical method of worldline instantons. The calculation is generalized to a model of quantum electrodynamics with broken Lorentz symmetry. Implications for the search of deviations from Lorentz invariance in the cosmic ray experiments are discussed.
It is shown, that specific properties of the instanton induced interaction between quarks leads to the anomalous violation of the OZI-rule in the $N\bar N\to ΦΦ$, $N\bar N\to Φγ$ reactions. In the framework of instanton model of the QCD vacuum, the energy dependence of the cross sections of these reactions is calculated.
We study the two-body decays of the gluino at full one-loop level in the Minimal Supersymmetric Standard Model with quark-flavour violation (QFV) in the squark sector. The renormalization is done in the DRbar scheme and hard gluon and photon radiations are included by adding the corresponding three-body decay widths. In the numerics the dependence of the gluino decay widths on the QFV parameters is discussed with special emphasis put on the separation of the electroweak and the SUSY QCD corrections. The main dependence stems from the $\tilde c_R - \tilde t_R$ mixing in the decays to up-type sq…
We study CP violation in $J/ψ\rightarrow Λ\barΛ$ decay. This decay provides a good place to look for CP violation. Some observables are very sensitive to the $Λ$ electric dipole moment $d_Λ$ and therefore can be used to improve the experimental upper bound on $d_Λ$. CP violations in the lepton pair decays of $J/ψ$ and $Υ$ are also discussed.
In this review, the $X^{0}-\bar{X}^{0}$\ mixing ($% X^{0}=B^{0},B_{s}^{0},K^{0}$) and its implication for CP\ violation in the standard model are discussed. Both direct and mixing induced CP\ violation for $K^{0}(\bar{K}^{0})$, $B^{0}(\bar{B}^{0})$\ and $B_{s}^{0}(% \bar{B}_{s}^{0})$\ are reviewed.
B-B-bar mixing involves three physical parameters: the magnitudes of the off-diagonal elements of the mass and decay matrices and their relative phase. They are related to the mass and width differences between the mass eigenstates and to the CP asymmetry in flavour-specific decays, a_fs. Introducing a new operator basis I present new, more precise theory predictions for the width differences in the B_s and B_d systems: in the Standard Model one finds Delta Gamma_s = 0.088 +/- 0.017 ps^{-1} and Delta Gamma_d = (26.7 +5.8/-6.5) * 10^{-4} ps^{-1}. Updates of the mass differences Delta M_d and De…
We compute the decay width of $h^0 \to c \bar{c}$ in the MSSM with quark flavor violation (QFV) at full one-loop level adopting the $\overline{\rm DR}$ renormalisation scheme. We study the effects of $\tilde{c}-\tilde{t}$ mixing, taking into account the constraints from the B meson data. We show that the full one-loop corrected decay width $Γ(h^0 \to c \bar{c})$ is very sensitive to the MSSM QFV parameters. In a scenario with large $\tilde{c}_{L,R}-\tilde{t}_{L,R}$ mixing $Γ(h^0 \to c \bar{c})$ can differ up to $\sim \pm 35\%$ from its SM value. After estimating the uncertainties of the width,…
Violations of the Okubo-Zweig-Iizuka (OZI) rule in $s\bar s <-> n\bar n = 1/2 (u\bar u + d\bar d)$ mixing and $ϕ$ production from nucleon-antinucleon annihilation are reviewed. Possible explanations are examined. We conclude that the two-step hadronic loops can explain these OZI violations naturally with proper consideration of cancellations between loops. No conclusive evidence exists for glueball states, $s\bar sn\bar n$ four quark states, instanton effects, and strange quarks in nucleon.
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…
Within the framework of an SU(5) SUSY GUT model, a possible general form of the neutrino mass matrix induced by R-parity violation is investigated. The model has matter fields \bar{5}'_{L}+5'_{L} in addition to the ordinary matter fields \bar{5}_{L}+10_{L} and Higgs fields H_u+\bar{H}_d. The R-parity violating terms are given by \bar{5}_{L} \bar{5}_{L} 10_{L}, while the Yukawa interactions are given by \bar{H}_d \bar{5}'_{L} 10_{L}. Since the matter fields \bar{5}'_L and \bar{5}_L are different from each other at the unification scale, the R-parity violation effects at a low energy scale appea…
Weak decays of beauty baryons like Λ_b (\barΛ_b) into Λ(\barΛ) and V (J^P = 1^-), where both decay products are polarized, offer interesting opportunities to perform tests of time reversal and CP violations and of CPT invariance. We propose a model independent parametrization of the angular distribution and of the polarization of the final resonances, by means of the spin density matrix. The transverse component of the polarization is sensitive to time reversal violations, moreover CP-and CPT-sensitive observables are defined.
We observe that the flavour symmetries of the Standard Model gauge sector, broken as they are in the Standard Model Yukawa Lagrangian, naturally suppress baryon and lepton number violation at low energies and, simultaneously, make it accessible at the LHC through resonant processes involving at least six fermions from all three generations. We establish a model independent classification of such transitions and identify two classes that give rise to particularly clean LHC signatures, namely $\bar t μ^+ e^+$ and $\bar t \bar t$ + jets.
The question is raised if a large violation of the OZI rule, recently observed in many channels in $N \bar N$ annihilation at rest, can be explained in the framework of the Skyrme model.
In perturbative QCD approach, based on the first order of isospin symmetry breaking, we study the direct $CP$ violation in the decay of $\bar{B}_s^0\toρ(ω)K^{*0}\to {π^+}{π^-}K^{*0}$. An interesting mechanism is applied to enlarge the $CP$ violating asymmetry involving the charge symmetry breaking between $ρ$ and $ω$. We find that the $CP$ violation is large by the $ρ-ω$ mixing mechanism when the invariant masses of the $π^+π^-$ pairs is in the vicinity of the $ω$ resonance. For the decay process of $\bar{B}^0_{s}\toρ(ω)K^{*0}\to{π^+}{π^-}K^{*0}$, the maximum $CP$ violation can reach $-59.12\%…
The general production {\it and} decay mechanism of $\ttbar$ in future high-energy $\epem$ colliders has been investigated in a model-independent way, focusing on an observation of possible CP violation. Angular asymmetries sensitive to CP violation either in the production {\it or} in the subsequent decays have been found. General considerations are illustrated through 1-loop effects induced by gluino exchange in the supersymmetric version of the Standard Model.
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.
We find a large CP violation effect within the Two-Higgs-Doublet-Model for the reaction $e^+e^-\to t\bar{t}H^0$ at future linear colliders. The CP-asymmetry arises already at the tree level as a result of interference between diagrams with $H^0$ emission from $t$ (and $\bar{t}$) and its emission from a $Z^0$ and can be about 10--20\%. In the best case one needs a few hundred $t\bar{t}H^0$ events to observe CP violation at the 3$σ$ level.
We studied the process $e^{+}e^{-} \to t\bar{c}+c\bar{t}$ in a R_{p} violating supersymmetric model with effects from both B- and L-violating interactions. The calculation shows that it is possible to either detect the R_{p} violating signal at the Next Linear Collider or get more stringent constraints on the heavy-flavor $\rlap/R_{p}$ couplings. A comparision with results from $γγ\to t\bar{c}+ c\bar{t}$ may allow to distinguish between B- and L-violating interactions. For very clean background conditions and R_{p} violation parameters close to present limits, a future detection of B-violating…
We consider the K^0 - \bar K^0 and B^0 - \bar B^0 mixings in the MSSM with the two-Higgs-doublet scalar sector featuring explicit CP violation, and the Yukawa sector of type II. In the case of strong mixing between CP-odd and CP-even states the existence of light charged Higgs is allowed in the model. The mass splitting Δm_{LS} and the amount of indirect CP violation εare calculated. In the limit of effective low-energy approximation the nonstandard effects are shown to be negligibly small in Δm_{LS} and εfor the K^0-mesons, being almost independent on the charged Higgs boson mass. However, fo…
CP violation in top physics is reviewed. The Standard Model has negligible effects, consequently CP violation searches involving the top quark may constitute the best way to look for physics beyond the Standard Model. Non-standard sources of CP violation due to an extended Higgs sector with and without natural flavor conservation and supersymmetric theories are discussed. Experimental feasibility of detecting CP violation effects in top quark production and decays in high energy e+ e-, gamma-gamma, mu+ mu-, pp and p-bar p colliders are surveyed. Searches for the electric, electro-weak and the …
Strictly solvable $d=4$ quantum field theory models with unitarity violation. Possible implications for baryon asymmetry of the Universe and dark matter
Institute for Nuclear Research RAS（俄罗斯科学院核物理研究所）；JINR Dubna（杜布纳联合核研究所）
We discuss the implications of CP violation as well as final state interaction phases in the experimental search for $D^0-\bar{D}^0$ mixing. At the present level of sensitivity, these are not yet a significant systematic experimental limitation.
We analyse the most recent experimental data regarding D^0 - \bar{D^0} mixing, allowing for CP violation. We focus on the dispersive part of the mixing amplitude, M^D_{12}, which is sensitive to new physics contributions. We obtain a constraint on the mixing amplitude: |M^D_{12}| < 6.2\times 10^{-11} MeV at 95% C.L. . This constraint is weaker by a factor of about three than the one which is obtained when no CP violation is assumed.
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.
We study neutrino masses and mixings based on the simplest SO(10) mass relations and the seesaw mechanism. We find that the requirement of large neutrino mixings determines the relative magnitude of the heavy Majorana neutrino masses in terms of the known quark mass hierarchy. This leads to specific predictions for the structure of the neutrino mixing matrix, the light neutrino masses, CP violation in neutrino oscillations, neutrinoless double b-decay and the baryon asymmetry.
The smallness of the quark and lepton parameters and the hierarchy between them could be the result of selection rules due to a horizontal symmetry broken by a small parameter. The same selection rules apply to baryon number violating terms. Consequently, the problem of baryon number violation in Supersymmetry may be solved naturally, without invoking any especially-designed extra symmetry. This mechanism is efficient enough even for low-scale flavor physics. Proton decay is likely to be dominated by the modes $K^+\barν_i$ or $K^0μ^+(e^+)$, and may proceed at observable rates.
The leading weak corrections to the production of top quark pairs via $q\bar{q} \to t\bar{t}$ in $p\bar{p}$ collisions are evaluated. The chromo-anapole form factor of the top quark and effects of parity violation are studied in the Standard Model (SM) and the Minimal Supersymmetric Model (MSSM). The parity violation effect in $q\bar{q} \to g \to t\bar{t}$ from the SM weak corrections is found to be very small. In the MSSM, the effects of parity violation can be enhanced for $\tanβ\equiv v_2/v_1 > \sqrt{m_t/m_b}$.
We consider a general two-Higgs-doublet model with CP violation in the scalar sector, that leads, at the one-loop level of the perturbation expansion, to CP-violation in the process $e^+e^- \to t\bar{t} \to l^\pm ...$ and $e^+e^- \to t\bar{t} \to b/\bar{b} ...$. The goal of this study is to include {\it consistently} CP-violating effects in distributions of top-quark decay products ($l^\pm$ or $b/\bar{b}$) that emerge {\it both} from $t\bar{t}$ production {\it and} from $t$ or $\bar{t}$ decay processes.
We reexamine the mass mixing and CP violation in the B\bar{B} system in general SU(2)_L \times SU(2)_R \times U(1) models related to the recent measurements. The right-handed contributions can be sizable in B\bar{B} mixing and CP asymmetry in B decays for a heavy W^\prime even with a mass about 3 TeV. On the other hand the lower bound on the mass of W^\prime can be taken down to approximately 300 GeV.
We analyze the scenario of baryogenesis through leptogenesis induced by the out-of-equilibrium decays of heavy Majorana neutrinos and pay special attention to CP violation. Extending a recently proposed resummation formalism for two-fermion mixing to decay amplitudes, we calculate the resonant phenomenon of CP violation due to the mixing of two nearly degenerate heavy Majorana neutrinos. Solving numerically the relevant Boltzmann equations, we find that the isosinglet Majorana mass may range from 1 TeV up to the grand unification scale, depending on the mechanism of CP violation and/or the fla…
In tagged cascade decays of the type P^0 (P^0-bar) -> M^0 / M^0-bar X -> f X there are two complex CPT-violating parameters: one in P^0 - P^0-bar mixing, the other one in M^0 - M^0-bar mixing. I analyze those decays and find that, in principle, the former parameter can be extracted from a careful comparison of their time dependences. CPT violation in M^0 - M^0-bar mixing, on the other hand, always appears entangled with ratios of decay amplitudes and cannot be extracted.
The complete analysis of the CP violation in the process $γγ\to t \bar{t}$ in frame of the Minimal Supersymmetric Model(MSSM) is presented. The CP-odd observables for describing the CP violating effects in polarized and unpolarized photon collisions, are calculated. We investigate the possible CP violation sources induced by the complex soft breaking parameters and study the CP violating effects contributed by gluino, neutralino and chargino sectors appearing in the loop diagrams. We find that it is possible to observe the CP violation effects in top quark pair production via polarized and unp…
In the framework of QCD factorization, based on the first order of isospin violation, we study direct CP violation in the decay of $\bar{B}_{s}^{0} \to K^{0}ρ^{0}(ω)\to K^{0}π^{+}π^{-}$ including the effect of $ρ-ω$ mixing. We find that the CP violating asymmetry is large via $ρ-ω$ mixing mechanism when the invariant mass of the $π^{+}π^{-}$ pair is in the vicinity of the $ω$ resonance. For the decay of $\bar{B}_{s}^{0} \to K^{0}ρ^{0}(ω)\to K^{0}π^{+}π^{-}$, the maximum CP violating asymmetries can reach about 46%. We also discuss the possibility to observe the predicted CP violating asymmetri…
A reliable prediction for $CP$ violation in $B^{0}_{d}$ vs $\bar{B}^{0}_{d}\rightarrow π^{+}π^{-}$ suffers from the penguin-diagram induced uncertainty. With the help of SU(3) relations, we show that both the magnitude and strong phase shift of the penguin amplitude can be approximately determined only from the branching ratios of $B^{0}_{d}\rightarrow π^{+}π^{-}$, $B^{0}_{d}\rightarrow K^{+}π^{-}$, and $B^{+}_{u}\rightarrow K^{0}π^{+}$.
In this work, we study the localized $CP$ violation and the branching fraction of the four-body decay $\bar{B}^0\rightarrow K^-π^+π^-π^+$ by employing a quasi-two-body QCD factorization approach. Considering the interference of $\bar{B}^0\rightarrow \bar{K}_0^*(700)ρ^0(770)\rightarrow K^-π^+π^-π^+$ and $\bar{B}^0\rightarrow \bar{K}^*(892)f_0(500)\rightarrow K^-π^+π^-π^+$ channels, we predict $\mathcal{A_{CP}}(\bar{B}^0\rightarrow K^-π^+π^-π^+)\in[0.15,0.28]$ and $\mathcal{B}(\bar{B}^0\rightarrow K^-π^+π^-π^+)\in[1.73,5.10]\times10^{-7}$, respectively, which shows that this two channels' interf…
To study violation of CP, T and/or CPT symmetries in the $K^0-\bar{K^0}$ systems, one has to parametrize the relevant mixing parameters and decay amplitudes in such a way that each parameter represents violation of these symmetries in a well-defined way. Parametrization is of course not unique and is always subject to phase ambiguities. We discuss these problems with freedom associated with rephasing of final (or intermediate) as well as initial states taken into account. We present a fully rephasing-invariant parametrization and a particular rephasing-dependent parametrization, and give a cou…
This is a written version of a series of lectures aimed at graduate students in the field of (theoretical and experimental) high energy physics. The main topics covered are: (i) The flavor sector of the Standard Model and the Kobayashi-Maskawa mechanism of CP violation; (ii) Formalism and theoretical interpretation of CP violation in meson decays; (iii) K decays; (iv) D decays; (v) B decays: b -> c c-bar s, b -> s s-bar s, b -> u u-bar d and b -> c u-bar s, u c-bar s; (vi) CP violation as a probe of new physics and, in particular, of supersymmetry.
A review of CP violation in the $B$ system and strategies to determine the unitarity triangle of the CKM matrix is given. We begin with an introduction to the description of CP violation in the Standard Model of electroweak interactions, and discuss the basic features of the theoretical framework to deal with non-leptonic B decays, which play the main role in this review. After a brief look at CP violation in the kaon system and a discussion of the rare decays $K^+\toπ^+ν\barν$ and $K_L\toπ^0ν\barν$, we turn to the formalism of $B^0_{d,s}$--$\bar{B^0_{d,s}}$ mixing, allowing us to explore impo…
We present the analytical expressions for the contributions of the order $O(\barα~\barα_s)$ and $O(\barα^2)$ corrections to the decay width of the Standard Model Higgs boson into the $\bar{b}b$-pair. The numerical value of the mixed QED and QCD correction of order $O(\barα~\barα_s)$ is comparable with the previously calculated terms in the perturbative series for $Γ(H^0\to\bar{b}b)$.
In this work we study the CP violation for $\bar{B^0}\to J/ψK_s$ and $\bar{B^0}\to ϕK_s$ up to leading and next-to-leading order QCD corrections in the standard model, two-Higgs-doublet model and the minimal supersymmetric extension of the standard model. We also study the effect of new physics on the branching ratios of these two decay modes. We find that within the parameter space constrained by the observation of the decay $b\to sγ$, new physics does not affect the CP asymmetries greatly, and the prediction of new physics to the branching ratios of $\bar{B^0}\to J/ψK_s$ and $\bar{B^0}\to ϕK…
The recent results on the CP violating parameters Re(e'/e) and Δϕ= ϕ_{00}-ϕ_{+-} reported by the KTeV Collaboration are analyzed with a view to constrain CP, T and CPT violations in a decay process. Combining with some relevant data compiled by the Particle Data Group, we find Re(e_2-e_0) = (0.85 +- 3.11)*10^{-4} and Im(e_2-e_0) = (3.2 +- 0.7)*10^{-4}, where Re(e_I) and Im(e_I) represent respectively CP/CPT and CP/T violations in decay of K^0 and \bar{K^0} into a 2πstate with isospin I.
A phenomenological analysis of the general two Higgs doublet model is presented. Possible constraints of the Yukawa couplings are obtained from the $K^0-\bar{K}^0, B^0-\bar{B}^0$ and $D^0-\bar{D}^0$ mixings. A much larger $D^0-\bar{D}^0$ mixing than the standard model prediction is possible. It is shown that the emerging of various new sources of CP violation in the model could strongly affect the determination of the unitarity triangle. It can be helpful to look for a signal of new physics by comparing the extracted angle $β$ from two different ways, such as from the process $B\to J/ψK_{S}$ a…
This work considers $K^0, \bar K^0$ meson mixings and oscillations via $K^0_1, K^0_2$ meson states at strangeness violation by weak interactions in two cases - without and with taking into account $K^0_1, K^0_2$ meson decays. In the first case the oscillation theory correctly describes $K^o, \bar K^o \to K^o, \bar K^o$ transition processes. In the second case, when we take into account meson decays, the oscillation theory cannot correctly describe this process at long distances since mainly $K^o_2$ mesons remain at long distances therefore the condition for oscillations is absent. So, at long …
We demonstrate that time-dependent studies of angular distributions for $B_s$ decays caused by $\bar b\to\bar cu\bar s$ quark-level transitions extract cleanly and model-independently the CKM angle $γ$. This CKM angle could be cleanly determined from untagged $B_s$ decays alone, if the lifetime difference between the $B_s$ mass eigenstates $B_s^L$ and $B_s^H$ is sizable. The time-dependences for the relevant tagged and untagged observables are given both in a general notation and in terms of linear polarization states and should exhibit large CP-violating effects. These observables may further…
We demonstrate how one may identify or constrain possible violation of $CP$, $T$ and $CPT$ symmetries in the $K^0$-$\bar{K^0}$ system in a way as phenomenological and comprehensive as possibie. For this purpose, we first introduce parameters which represent violation of these symmetries in mixing parameters and decay amplitudes in a well-defined way. After discussing some characteristics of these parameters, we derive formulae which relate them to the experimentally measured quantities. We then carry out a numerical analysis with the help of the Bell-Steinberger relation to derive constraints …
We discuss the correlation between the CP violating Dirac phase of the lepton mixing matrix and the cosmological baryon asymmetry based on the leptogenesis in the minimal seesaw model with two right-handed Majorana neutrinos and the trimaximal mixing for neutrino flavors. The sign of the CP violating Dirac phase at low energy is fixed by the observed cosmological baryon asymmetry since there is only one phase parameter in the model. According to the recent T2K and NO$ν$A data of the CP violation, the Dirac neutrino mass matrix of our model is fixed only for the normal hierarchy of neutrino mas…
We study the CP violation in two-body nonleptonic decays of $B_c$ meson. We concentrate on the decay channels which contain at least one excited heavy meson in the final states. Specifically, the following channels are considered: $B_c\to c\bar c(2S, 2P)+\bar cq(1S, 1P)$, $B_c\to c\bar c(1S)+\bar cq(2S, 2P)$, $B_c\to c\bar c(1P)+\bar cq(2S)$, $B_c\to c\bar c(1D)+\bar cq(1S, 1P)$, and $B_c\to c\bar c(3S)+\bar cq(1S)$. The improved Bethe-Salpeter method is applied to calculate the hadronic transition matrix element. Our results show that some decay modes have large branching ratios, which is of …
We present an estimate of the partial width of X(3872) into p p-bar under the assumption that it is a weakly-bound hadronic molecule whose constituents are a superposition of the charm mesons D^{*0} D-bar^0 and D^{0} D-bar^{*0}. The p p-bar partial width of X is therefore related to the cross section for p p-bar to D^{*0} D-bar^0 near the threshold. That cross section at an energy well above the threshold is estimated by scaling the measured cross section for p p-bar to K^{*-} K^+. It is extrapolated to the D^{*0} D-bar^0 threshold by taking into account the threshold resonance in the 1^{++} c…
There exist experimental hints from the B sector for CP violation beyond the Standard Model (SM) CKM paradigm. An anomalous dimuon asymmetry was reported by the D0 collaboration, while tension exists between $B \to τν$ and $S_{ψK}$. These measurements, disfavoring the SM at the ~3$σ$ level, can be explained by new physics in both $B_d$-$\bar{B}_d$ and $B_s$- $\bar{B}_s$ mixing, arising from (1) new bosonic degrees of freedom at or near the electroweak scale, and (2) new, large CP-violating phases. These two new physics ingredients are precisely what is required for electroweak baryogenesis to …
The process of top-quark pair production at future high-energy $e^+ e^-$ linear colliders has been investigated as a possible test of physics beyond the Standard Model. Non-standard interactions have been assumed both for the production and for the subsequent decay of the top quarks. The energy spectrum of the single lepton $l^\pm$ and the energy correlation of $l^+$ and $l^-$ emerging from the process $e^+e^-\to t\bar{t}\to l^\pm X/l^+l^-X$ are calculated. The energy- spectrum asymmetry of $l^+$ and $l^-$ is considered as a measure of CP violation. An optimal method to determine whether CP vi…
We studied the process $γγ\to t\bar{c}+c\bar{t}$ in a $R_{p}$ violating supersymmetric Model with the effects from both B- and L-violating interactions. The calculation shows that it is possible to detect a $R_{p}$ violating signal at the Next Linear Collider. Information about the B-violating interaction in this model could be obtained under very clean background, if we take the present upper bounds for the parameters in the supersymmetric $\rlap/ R_{p}$ interactions. Even if we can not detect a signal of $\rlap/R_{p}$ in the experiment, we may get more stringent constraints on the heavy-flav…
