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     

<Emphasis Type="Italic">V</Emphasis>-<Emphasis Type="Italic">A</Emphasis> sum rules with <Emphasis Type="Italic">D</Emphasis> = 10 operators

The difference of vector and axial-vector charged current correlators is analyzed by means of QCD sum rules. The contribution of 10-dimensional 4-quark condensates is calculated and its value is estimated within the framework of the factorization hypothesis. It is compared to the result obtained from an operator fit of Borel sum rules in the complex q ²-plane, calculated from experimental data on hadronic -decays. This fit gives accurate values of the light quark condensate and the quark-gluon mixed condensate. The size of the high-order operators and the convergence of the operator series are discussed.Received: 10 May 2004, Revised: 7 September 2004, Published online: 18 November 2004     

<Emphasis Type="Italic">B</Emphasis><Subscript><Emphasis Type="Italic">K</Emphasis></Subscript> from the lattice with Wilson quarks

We report our results for the bag parameter B _K obtained from the quenched simulations on the lattice with Wilson fermions for three values of the lattice spacing. We implemented the method by which no subtraction of the mixing with other four-fermion operators is needed. Our final result, in terms of the renormalization group invariant bag parameter, is .Received: 9 July 2004, Revised: 27 July 2004, Published online: 21 September 2004     

<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.     

<Emphasis Type="Italic">K</Emphasis><Subscript><Emphasis Type="Italic">e</Emphasis>3</Subscript> decays and CKM unitarity

We present a detailed numerical study of the K_e3 decays to in chiral perturbation theory with virtual photons and leptons. We describe the extraction of the CKM matrix element |V_us| from the experimental K_e3 decay parameters. We propose a consistency check of the K ⁺ _e3 and K⁰_e3 data that is largely insensitive to the dominating theoretical uncertainties, in particular the contributions of . Our analysis is highly relevant in view of the recent high statistics measurement of the K ⁺ _e3 branching ratio by E865 at Brookhaven which does not indicate any significant deviation from CKM unitarity but rather a discrepancy with the present K⁰_e3 data.Received: 22 January 2004, Published online: 30 April 2004Work supported in part by IHP-RTN, Contract No. HPRN-CT2002-00311 (EURIDICE) and by Acciones Integradas, Project No. 19/2003 (Austria), HU2002-0044 (MCYT, Spain)     

Electronic structure of crystal-forming fulborenes B<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript>N<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript>

A general approach is formulated to the design of crystal-forming fullerene-like clusters X _n Y _n from which zeolite-like covalent crystals based on IV-IV, III-V, and II-VI binary semiconductor compounds with diamond-like sp ³ bonds can be constructed and synthesized by means of copolymerization through faces. A number of the smallest sized crystal-forming boron nitride clusters are constructed, such as the B₁₂N₁₂, B₁₆N1₆, B₁₈N₁₈, B₂₄N₂₄, B₃₆N₃₆, and B ₆₀N₆₀ fulborenes. The optimized configurations, electronic structures, charge transfers, band gaps, total energies, cohesive energies, and electron density maps of the clusters are calculated using the spin-restricted Hartree-Fock method in the 6–31G basis set. Comparative calculations of the B₆₀N₆₀ fulborene with the use of the density functional theory method have demonstrated that the spin-restricted Hartree-Fock method in the 6–31G basis set is optimum from the standpoint of the accuracy and efficiency.     

Jet production in <Emphasis Type="Italic">pA</Emphasis> and <Emphasis Type="Italic">AA</Emphasis> collisions in the perturbative QCD pomeron model

Inclusive cross-sections for gluon jet production are studied numerically in the perturbative QCD pomeron model for pA and central AA collisions at high energies. Two forms for the inclusive cross-sections, with and without emission from the triple pomeron vertex, are compared. The difference was found to reduce to a numerical factor for momenta below the saturation momentum Q _s. Above Q _s no difference was found at all. For pA collisions the gluon spectrum was found to be at momenta k below Q _s and above it. For central AA collisions it was found to be at momenta k below Q _s and above it. At large k the spectrum goes like , flattening with energy. The multiplicities turned out to be proportional to A ^0.7 for pA collisions and A for central AA collisions with a good precision. In the latter case they are becoming more peaked at the center with the growth of energy. Their absolute values are high and grow rapidly with energy in accordance with the high value of the BFKL intercept.Received: 12 October 2004, Revised: 22 November 2004, Published online: 21 January 2005     

Inclusive measure of |<Emphasis Type="Italic">V</Emphasis><Subscript><Emphasis Type="Italic">ub</Emphasis></Subscript>| with the analytic coupling model

By analyzing B→X _u ℓ ν _ℓ spectra with a model based on soft-gluon resummation and an analytic time-like QCD coupling, we obtain

<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.     

Final-state polarization in <Emphasis Type="Italic">B</Emphasis><Stack><Subscript><Emphasis Type="Italic">s</Emphasis></Subscript><Superscript>0</Superscript></Stack> decays

Certain B _s ⁰→V ₁ V ₂ decays (V _i is a vector meson) can be related by flavor SU(3) symmetry to corresponding B _d ⁰→V ₃ V ₄ decays. In this paper, we show that the final-state polarization can be predicted in the B _s ⁰ decay, assuming polarization measurements of the B _d ⁰ decay. This can be done within the scenario of penguin annihilation (PA), which has been suggested as an explanation of the unexpectedly large transverse polarization in B→φ K ^*. PA is used to estimate the breaking of flavor SU(3) symmetry in pairs of decays. Two of these for which PA makes a reasonably precise prediction of the size of SU(3) breaking are (B _s ⁰→φ φ,B _d ⁰→φ K ^0*) and ( ). The polarization measurement in the B _d ⁰ decay can be used to predict the transverse polarization in the B _s ⁰ decay and will allow for testing of PA as well as the other assumptions in the analysis.     

Radiative <Emphasis Type="Italic">K</Emphasis><Subscript><Emphasis Type="Italic">e</Emphasis>3</Subscript> decays revisited

Motivated by recent experimental results and ongoing measurements, we review the chiral perturbation theory prediction for decays. Special emphasis is given to the stability of the inner bremsstrahlung-dominated relative branching ratio versus the K _e3 form factors, and on the separation of the structure-dependent amplitude in differential distributions over the phase space. For the structure-dependent terms, an assessment of the order p ⁶ corrections is given, in particular, a full next-to-leading order calculation of the axial component is performed. The experimental analysis of the photon energy spectrum is discussed, and other potentially useful distributions are introduced.Received: 9 December 2004, Published online: 21 February 2005PACS: 13.20.Eb, 11.30.Rd, 12.39.Fe     

Measurement of dijet production at low <Emphasis Type="Italic">Q</Emphasis><Superscript>2</Superscript> at HERA

Triple differential dijet cross sections in interactions are presented in the region of photon virtualities 2 < Q ² < 80 GeV², inelasticities 0.1 < y < 0.85, jet transverse energies E ^* _{T 1} > 7 GeV, E ^* _{T 2} > 5 GeV, and pseudorapidities . The measurements are made in the centre-of-mass frame, using an integrated luminosity of 57 pb^-1. The data are compared with NLO QCD calculations and LO Monte Carlo programs with and without a resolved virtual photon contribution. NLO QCD calculations fail to describe the region of low Q ² and low jet transverse energies, in contrast to a LO Monte Carlo generator which includes direct and resolved photon interactions with both transversely and longitudinally polarised photons. Initial and final state parton showers are tested as a mechanism for including higher order QCD effects in low E _T jet production.Received: 13 January 2004, Revised: 21 July 2004, Published online: 18 August 2004     

The difference between <Emphasis Type="Italic">n</Emphasis>-dimensional regularization and <Emphasis Type="Italic">n</Emphasis>-dimensional reduction in QCD

We discuss the difference between n-dimensional regularization and n-dimensional reduction for processes in QCD which have an additional mass scale. Examples are heavy flavor production in hadron-hadron collisions or on-shell photon-hadron collisions where the scale is represented by the mass m. Another example is electroproduction of heavy flavors where we have two mass scales given by m and the virtuality of the photon . Finally we study the Drell-Yan process where the additional scale is represented by the virtuality of the vector boson ( ). The difference between the two schemes is not accounted for by the usual oversubtractions. There are extra counter terms which multiply the mass scale dependent parts of the Born cross sections. In the case of the Drell-Yan process it turns out that the off-shell mass regularization agrees with n-dimensional regularization.Received: 12 January 2005, Published online: 21 February 2005PACS: 11.15.Bt, 12.38.Bx, 13.85.NiJ. Smith: Partially supported by the National Science Foundation grant PHY-0354776.     

<Emphasis Type="Italic">B</Emphasis> to light meson transition form factors calculated in perturbative QCD approach

We calculate the , (P is the light pseudoscalar meson, V the light vector meson) form factors in the large-recoil limit in the perturbative QCD approach, including both the vector (axial vector) and tensor operators. In general there are two leading components and for the B meson wave functions. We consider both contributions of them. Sudakov effects ( and threshold resummation) are included to regulate the soft end-point singularity. By choosing the hard scale as the maximum virtualities of the internal particles in the hard b quark decay amplitudes, Sudakov factors can effectively suppress the long-distance soft contribution. The hard contribution can be dominant in these approaches. Received: 27 December 2002 / Published online: 5 May 2003 RID="a" ID="a" e-mail: lucd@mail.ihep.ac.cn RID="b" ID="b" e-mail: yangmz@mail.ihep.ac.cn     

<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.     

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     

The <Emphasis Type="Italic">N</Emphasis> = <Emphasis Type="Italic">Z</Emphasis><Emphasis Type="Italic">f</Emphasis><Subscript>7/2</Subscript>-shell nuclei: Experimental highlights

During the last decade, as the experimental and computing means and techniques have rapidly evolved, the experimental investigation of the f_7/2-shell nuclei has gained renewed interest. TheN = Z nuclei studied with the GASP array range from ⁴⁴Ti to ⁵²Fe. The results extended the knowledge of their structure up to high spins and excitation energies, above band terminations, where the competition with the charged-particles emission was initially thought to obscure the possibility of gamma-ray spectroscopy investigation. The paper highlights some of the most outstanding properties of these nuclei such as the nuclear rotation and backbending effects, band termination states, yrast traps, non-natural parity bands, competition between T = 0 and T = 1 pn pairing modes.Received: 30 October 2002, Published online: 16 March 2004PACS: 21.10.-k Properties of nuclei; nuclear energy levels - 21.60.Cs Shell model - 23.20.Lv transitions and level energies - 27.40. + z C.A. Ur: On leave from NIPNE Bucharest, Romania     

Discrete breathers in biatomic crystals of <Emphasis Type="Italic">AB</Emphasis> and <Emphasis Type="Italic">A</Emphasis><Subscript>3</Subscript><Emphasis Type="Italic">B</Emphasis> composition

The conditions for the existence of discrete breathers (DBs) in biatomic crystals of AB and A ₃ B composition are established, and their properties are studied by means of molecular mechanics using the examples of CuAu and Pt₃Al, respectively. The phonon spectra of the crystals are analyzed, and a gap in the phonon spectrum of CuAu is obtained via considerable homogeneous elastic strain. There is a gap in the phonon spectrum of the Pt₃Al crystal at zero strain, due to the considerable difference between the atomic weights of its components. The frequencies at which discrete breathers can exist in the considered crystals are determined. The energy localized on different types of DBs is estimated. The propagation of a current pulse through Pt₃Al resulting in the excitation of DBs with mild nonlinearity is simulated.     

Study of <Emphasis Type="Italic">N</Emphasis> = <Emphasis Type="Italic">Z</Emphasis> nuclei in variation-after-projection framework

Variation-after-projection (VAP) calculations in conjunction with the Hartree- Bogoliubov (HB) ansatz have been carried out for A = 68-88, N = Z nuclei. In this framework, the yrast spectra with , B(E2) transition probabilities and deformation parameter ( ) have been obtained. A pairing interaction for like particles as well as protons and neutrons has been included in the model for a two-body interaction.Received: 28 April 2003, Revised: 20 March 2004, Published online: 14 September 2004PACS: 21.10.-k Properties of nuclei; nuclear energy levels - 21.60.-n Nuclear structure models and methods - 27.50. + e