Asymmetries in rare radiative leptonic and semileptonic decays of <Emphasis Type="Italic">B</Emphasis> mesons

The time-dependent and time-independent CP asymmetries $ A_{CP}^{B_q^0 \to f} \left( \tau \right) $ A_{CP}^{B_q^0 \to f} \left( \tau \right) and $ A_{CP}^{B_q^0 \to f} \left( {\hat s} \right) $ A_{CP}^{B_q^0 \to f} \left( {\hat s} \right) for rare semileptonic and radiative leptonic decays of B mesons are calculated by the method of helicity amplitudes. The sensitivity of CP asymmetries to various extensions of the Standard Model that have an operator basis that is identical to the operator basis of the Standard Model is investigated. It is shown that, by combining information about the form of the charge lepton asymmetry A _FB at small values of the square of the invariant dilepton mass and information about the average value of the time-dependent CP asymmetry, one can in principle determine the relative phases of the Wilson coefficients C _7γ , C _9V , and C _10A in the effective Hamiltonian for b → {d, s}ℓ⁺ℓ⁻ transitions.     

<Emphasis Type="Italic">B</Emphasis>-meson decays into charmonium states in the ATLAS experiment

The paper presents several recent ATLAS results on the analyses of B-meson decays into charmonium states. These include the measurements of B⁺ mass and the fractions of J/ψ mesons produced in b-hadron decays in pp collisions at \(\sqrt s\) = 13 TeV in the center of mass system. The measured partial widths and polarizations in B _c ⁺ → J/ψD _s ^(*)+ decays and CP-violation parameters in B _s ⁰ → J/ψ? decays in pp collisions at 7 and 8 TeV in the center of mass system are also presented.     

<Emphasis Type="Italic">B</Emphasis><Subscript><Emphasis Type="Italic">c</Emphasis></Subscript> meson rare decays in the light-cone quark model

We investigate the rare decays \(B_{c} \rightarrow D_{s}(1968)\ell \overline{\ell}\) and \(B_{c}\rightarrow D_{s}^{*}(2317) \ell \overline{\ell}\) in the framework of the light-cone quark model (LCQM). The transition form factors are calculated in the space-like region and then analytically continued to the time-like region via exponential parametrization. The branching ratios and longitudinal lepton polarization asymmetries (LPAs) for the two decays are given and compared with each other. The results are helpful for investigating the structure of B _c meson and for testing the unitarity of CKM quark mixing matrix. All these results can be tested in the future experiments at the LHC.     

<Emphasis Type="Italic">B</Emphasis>-meson physics: <Emphasis Type="Italic">CP</Emphasis> violation and semileptonic decays

The paper represents a review of our present knowledge on the phenomenology of weak decays of quarks and their role in the determination of the parameters of the Standard Model. Specifically, we focus on CP violation in B decays and the determination of the Cabibbo-Kobayashi-Maskawa matrix element V_cb from exclusive and inclusive semileptonic B decays. We also briefly discuss phenomeno-logical applications concerning the electron energy spectra in inclusive semileptonic B and B_c decays.     

On the role of the final-state interactions in rare <Emphasis Type="Italic">B</Emphasis> decays

The effects of final-state interactions (FSI) in hadronic B decays are investigated. The model for FSI, based on Regge phenomenology of high-energy hadronic interactions, is proposed. It is shown that this model explains the pattern of phases in matrix elements of B → ππ and B → ρρ decays. These phases play an important role for CP violation in B decays. The most precise determination of the unitarity triangle angle α from B _d → ρπ decays is performed. The relation between CP asymmetries in B → Kπ decays is discussed. It is emphasized that the large-distance FSI can explain the structure of polarizations of the vector mesons in B decays and other puzzles like a very large branching ratio of the B decay to $ \bar \Xi $ \bar \Xi _c Λ _c .     

Isospin analysis of charmless <Emphasis Type="Italic">B</Emphasis>-meson decays

We discuss the determination of the CKM angle \(\alpha \) using the non-leptonic two-body decays \(B\rightarrow \pi \pi \), \(B\rightarrow \rho \rho \) and \(B\rightarrow \rho \pi \) using the latest data available. We illustrate the methods used in each case and extract the corresponding value of \(\alpha \). Combining all these elements, we obtain the determination \(\alpha _\mathrm{dir}={({86.2}_{-4.0}^{+4.4} \cup {178.4}_{-5.1}^{+3.9})}^{\circ }\). We assess the uncertainties associated to the breakdown of the isospin hypothesis and the choice of the statistical framework in detail. We also determine the hadronic amplitudes (tree and penguin) describing the QCD dynamics involved in these decays, briefly comparing our results with theoretical expectations. For each observable of interest in the \(B\rightarrow \pi \pi \), \(B\rightarrow \rho \rho \) and \(B\rightarrow \rho \pi \) systems, we perform an indirect determination based on the constraints from all the other observables available and we discuss the compatibility between indirect and direct determinations. Finally, we review the impact of future improved measurements on the determination of \(\alpha \).     

Polarization effects in rare <Emphasis Type="Italic">K</Emphasis> decays

We review some aspects of rare kaon decays with the polarization of outgoing muons that allows one to study a number of interesting CP-odd or T-odd observables.     

Non-leptonic <Emphasis Type="Italic">B</Emphasis> decays into a charmed tensor meson

In the framework of factorization and the heavy quark effective theory, modes are analyzed. We adopt the result from the QCD sum rule calculation for the hadronic matrix elements at leading order of and . The QCD sum rule results are well compatible with the current data, with the prediction for the branching ratios and for . We give constraints on the interception and the slope parameter of the leading Isgur-Wise function from the experimental bounds. It is argued that the observation of non-zero directly measures the non-factorizable effects. Received: 18 July 2002 / Revised version: 21 October 2002 / Published online: 14 March 2003 RID="a" ID="a" e-mail: jplee@phya.yonsei.ac.kr     

Quark diagram analysis of <Emphasis Type="Italic">B</Emphasis>-meson emitting vector (<Emphasis Type="Italic">V</Emphasis>) and vector (<Emphasis Type="Italic">V</Emphasis>) mesons

This paper presents the two body weak nonleptonic decays of B-mesons emitting vector (V) and vector (V) mesons within the framework of the diagrammatic approaches at flavor SU(3) symmetry. We have investigated exclusive two body decays of B-meson using model independent quark diagram scheme. We have shown that the recent measurement of the two body exclusive decays of B-mesons can allow us to determine the magnitude and even sign of the QD amplitude for B → VV decays. Therefore, we become able to make few predictions for their branching fractions.     

<Emphasis Type="Italic">B</Emphasis> decays into light scalar particles and glueball

The recent observations of f ₀(980) in charmless B decays motivate further studies of scalar particle and glueball production in these processes. Amplitudes for charmless two-body B decays involving the members of the scalar nonet are presented based on the symmetries of the dominant penguin contribution. Different scenarios for the lightest scalar nonet are investigated in view of the presently available data. We describe the evidence from B decays for f ₀(1500) with a flavor octet like mixing and the hints towards the members of the nonet of lowest mass. There is further support for the hypothesis of a broad 0 ^{+ +} glueball acting as coherent background especially in . The estimated B decay rates into gluonic mesons represent a sizable fraction of the theoretically derived decay rate for .Received: 23 April 2004, Revised: 27 October 2004, Published online: 21 December 2004Work supported in part by the Schweizerischer Nationalfonds.     

Spectroscopy and Regge trajectories of heavy quarkonia and <Emphasis Type="Italic">B</Emphasis><Subscript><Emphasis Type="Italic">c</Emphasis></Subscript> mesons

The mass spectra of charmonia, bottomonia and B _c mesons are calculated in the framework of the QCD-motivated relativistic quark model based on the quasipotential approach. The dynamics of heavy quarks and antiquarks is treated fully relativistically without application of the nonrelativistic v ²/c ² expansion. The known one-loop radiative corrections to the heavy quark potential are taken into account perturbatively. The heavy quarkonium masses are calculated up to rather high orbital and radial excitations (L=5, n _r =5). On this basis the Regge trajectories are constructed both in the total angular momentum J and radial quantum number n _r . It is found that the daughter trajectories are almost linear and parallel, while parent trajectories exhibit some nonlinearity in the low mass region. Such nonlinearity is most pronounced for bottomonia and is only marginal for charmonia. The obtained results are compared with the available experimental data, and a possible interpretation of the new charmonium-like states above open charm production threshold is discussed.     

Two-photon decays of neutral <Emphasis Type="Italic">B</Emphasis> mesons within a model featuring one universal extra dimension

Contributions to the B _s(d) → γγ decay amplitude beyond the Standard Model are estimated within a model featuring one universal extra dimension. It is found that these additional contributions may amount to 6 or 7% of the branching ratios evaluated within the Standard Model.     

<Emphasis Type="Italic">B</Emphasis> and <Emphasis Type="Italic">B</Emphasis><Subscript><Emphasis Type="Italic">s</Emphasis></Subscript> decay constants from moments of finite energy sum rules in QCD

We use an appropriate combination of moments of finite energy sum rules in QCD in order to compute the B _q -meson decay constants f _B and . We perform the calculation using a two-loop computation of the imaginary part of the pseudoscalar two point function in terms of the running bottom quark mass. The results are stable against the so-called QCD duality threshold, and they are in agreement with the estimates obtained from Borel transform QCD sum rules and lattice computations.Received: 28 July 2004, Revised: 10 September 2004, Published online: 23 November 2004PACS: 12.38.Bx, 12.38.LgSupported by MCYT-FEDER under contract FPA2002-00612.     

Wave functions and decay constants of <Emphasis Type="Italic">B</Emphasis> and <Emphasis Type="Italic">D</Emphasis> mesons in the relativistic potential model

With the decay constants of D and D _s mesons measured in experiment recently, we revisit the study of the bound states of quark and antiquark in B and D mesons in the relativistic potential model. The relativistic bound state wave equation is solved numerically. The masses, decay constants and wave functions of B and D mesons are obtained. Both the masses and decay constants obtained here can be seen as consistent with the experimental data. The wave functions can be used in the study of B and D meson decays.     

Measurement of polarization angular coefficients in <Emphasis Type="Italic">Z</Emphasis> boson leptonic decays with ATLAS at the LHC

This paper presents the complete set of polarization angular coefficients A _0?7 describing lepton angular distributions in Z boson decay, which were measured at the ATLAS experiment in proton–proton collisions with the energy √s = 8 TeV. Theoretical values for the difference A ₀ ? A ₂ calculated in the fixed-order QCD perturbation theory O(α _s ² ), demonstrate significant deviation from the measured data, which indicates the necessity of taking into account higher order corrections. The evidence of nonzero coefficients A _5,6,7 was obtained for the first time, in accordance with theoretical calculations in O(α _s ² ) approximation. Measurement of the polarization angular coefficients A _i is important for subsequent precision measurement of parameters of the electroweak model at the LHC, such as the sine of Weinberg electroweak mixing angle sin² θ _W and the W boson mass.     

New measurements on physics of <Emphasis Type="Italic">B</Emphasis>-hadrons in ATLAS experiment

Recent results on B-hadron physics in ATLAS are reviewed. A new measurement of CP-violating parameters in B _s → J/ψφ decay is performed on full Run 1 statistics. Branching fraction BR(B _s → μ⁺μ^?) = (0.9 _?0.8 ^+1.1 )×10^?9 is measured, below the Standard Model (SM) prediction.     

Uncertainties in estimating <Emphasis Type="Italic">B</Emphasis><Subscript><Emphasis Type="Italic">c</Emphasis></Subscript> hadronic productionand comparisons of the production at TEVATRON and LHC

The uncertainties in estimating the hadronic production of the B _c meson are studied in the framework of the complete approach of perturbative QCD and the gluon-gluon fusion mechanism. Quantitative comparisons of the production at TEVATRON and LHC are made. Considering the detectors at TEVATRON and LHC, we have also estimated the production with proper kinematic cuts. Based on the results, we conclude that the experimental studies of the B _c meson at the two colliders will be complementary and mutually stimulative. We find that as the CM energy is increasing from RUN-I to RUN-II at TEVATRON, the production cross section increases by about .Received: 21 July 2004, Published online: 18 November 2004PACS: 12.38.Bx, 13.85.Ni, 14.40.Nd, 14.40.Lb     

Annihilation semileptonic decays of <Emphasis Type="Italic">B</Emphasis> mesons and the model dependence on the choice of the distribution amplitude

The rare semileptonic B-meson decay B → ??⁺?^? is considered. The partial decay rate integrated over the 1–8 GeV² interval of the dilepton invariant mass squared is computed with a 10% systematic uncertainty arising from the model dependence of the distribution amplitude. The purely perturbative contribution to the decay probability amounts to ? ～ 10^?12, which suggests that the LHC experiments could observe the B → ??⁺?^? decay in a few years of data taking.     

Bound on dissipative effects from semileptonic neutral <Emphasis Type="Italic">B</Emphasis>-meson decays

The semileptonic decay asymmetry \(\mathcal {A}_{{\Delta }m}\) is studied within the open quantum systems approach to the physics of the neutral meson \(B^0\)–\(\overline{B^0}\) system: this extended treatment takes into account possible non-standard, dissipative effects induced by the presence of an external environment. A bound on these effects is provided through the analysis of available experimental data from the Belle Collaboration.