Exact Results for Topological Strings on Resolved <Emphasis Type="Italic">Y</Emphasis><Superscript><Emphasis Type="Italic"> p</Emphasis>,<Emphasis Type="Italic">q</Emphasis></Superscript> Singularities

We obtain exact results in α′ for open and closed A-model topological string amplitudes on a large class of toric Calabi-Yau threefolds by using their correspondence with five dimensional gauge theories. The toric Calabi-Yaus that we analyze are obtained as minimal resolution of cones over Y ^p,q manifolds and give rise via M-theory compactification to SU(p) gauge theories on . As an application we present a detailed study of the local case and compute open and closed genus zero Gromov-Witten invariants of the orbifold. We also display the modular structure of the topological wave function and give predictions for higher genus amplitudes. The mirror curve in this case is the spectral curve of the relativistic A ₁ Toda chain. Our results also indicate the existence of a wider class of relativistic integrable systems associated to generic Y ^p,q geometries.     

<Emphasis Type="Italic">EPJdirect</Emphasis>

Quark mass effects are analyzed at high Q² in the current fragmentation region of DIS. It is found that the linear combination F ₂ -2.75F ^c ₂ scales at large Q² and small x. We obtained a lower bound for the ratio F ^c ₂/F ₂ which lies very close to the data from HERA. Received: 14 January 2002 / Revised version: 9 October 2002 Published online: 9 December 2002 RID="a" ID="a" e-mail: ryutin@th1.ihep.su     

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

Analysis of the <Emphasis Type="Italic">Y</Emphasis>(4140) with QCD sum rules

In this article, we assume that there exists a scalar D_s^*[`(D)]<sub>s</sub><sup>*</sup>D_{s}^{\ast}{\bar{D}}_{s}^{\ast} molecular state in the J/ψ φ invariant mass distribution, and we study its mass using the QCD sum rules. The predictions depend heavily on the two criteria (pole dominance and convergence of the operator product expansion) of the QCD sum rules. The value of the mass is about M<sub>Ds<sup>*</sup>[`(D)]s^*</sub>=(4.43±0.16)M_{D_{s}^{\ast}{\bar{D}}_{s}^{\ast}}=(4.43\pm0.16)  GeV, which is inconsistent with the experimental data. The D_s^*[`(D)]_s^*D_{s}^{\ast}{\bar{D}}_{s}^{\ast} is probably a virtual state and is not related to the meson Y(4140). Another possibility, such as a hybrid charmonium, is not excluded.     

Effects of <Emphasis Type="Italic">d</Emphasis>-wave pairing in <Emphasis Type="Italic">n</Emphasis>-type high-temperature superconductors with anisotropic impurity scattering

The temperature dependences of the resistivity of single-crystal films of the Nd_{2 − x} Ce _x CuO_{4 + δ} n-type superconductors with x = 0.14 (underdoped region) and x = 0.15 (optimal doping region) and different degrees of disorder δ have been investigated in various magnetic fields (B ‖ c, J ‖ ab) in the temperature range 0.4–300 K. It has been demonstrated that there are differences in the behavior of the dependences of the slope of the upper critical field $ (dB_{c2} /dT)_{T \to T_c } $ (dB_{c2} /dT)_{T \to T_c } on the disorder parameter for the underdoped samples (x = 0.14) and the samples with the optimal doping (x = 0.15). The study of the dependence of the slope of the upper critical field on the degree of disorder has made it possible to discriminate experimentally between the superconductors with the d pairing and anisotropic s pairing. It has been revealed that the relative stability of the n-type superconductor with the optimal doping with respect to disordering is possibly due to the strong anisotropy of impurity scattering with symmetry of the d type.     

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     

Dynamical Differential Equations Compatible with Rational <Emphasis Type="Italic">qKZ</Emphasis> Equations

For the Lie algebra _N we introduce a system of differential operators called the dynamical operators. We prove that the dynamical differential operators commute with the _N rational quantized Knizhnik–Zamolodchikov difference operators. We describe the transformations of the dynamical operators under the natural action of the _N Weyl group.Mathematics Subject Classifications (2000). 17B37, 17B80, 81R10.     

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.     

Trace anomaly and quasi-particles in finite temperature <Emphasis Type="Italic">SU</Emphasis>(<Emphasis Type="Italic">N</Emphasis>) gauge theory

We consider deconfined matter in SU(N) gauge theory as an ideal gas of transversely polarized quasi-particle modes having a temperature-dependent mass m(T). Just above the transition temperature, the mass is assumed to be determined by the critical behavior of the energy density and the screening length in the medium. At high temperature, it becomes proportional to T as the only remaining scale. The resulting (trace anomaly based) interaction measure Δ=(ϵ−3P)/T ⁴ and energy density are found to agree well with finite temperature SU(3) lattice calculations.     

<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.     

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      

Measurement of high-<Emphasis Type="Italic">Q</Emphasis><Superscript>2</Superscript> charged current cross sections in <Emphasis Type="Italic">e</Emphasis><Superscript> + </Superscript><Emphasis Type="Italic">p</Emphasis> deep inelastic scattering at HERA

Cross sections for e ⁺ p charged current deep inelastic scattering at a centre-of-mass energy of have been determined with an integrated luminosity of collected with the ZEUS detector at HERA. The differential cross sections , and for are presented. In addition, has been measured in the kinematic range and . The predictions of the Standard Model agree well with the measured cross sections. The mass of the W boson propagator is determined to be from a fit to . The chiral structure of the Standard Model is also investigated in terms of the (1-y)² dependence of the double-differential cross section. The structure-function has been extracted by combining the measurements presented here with previous ZEUS results from e ^- p scattering, extending the measurement obtained in a neutrino-nucleus scattering experiment to a significantly higher Q ² region.Received: 17 July 2003, Published online: 12 November 2003 ^a supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) ^b supported by the German Federal Ministry for Education and Research (BMBF), under contract numbers HZ1GUA 2, HZ1GUB 0, HZ1PDA 5, HZ1VFA 5 ^c supported by the MINERVA Gesellschaft für Forschung GmbH, the Israel Science Foundation, the U.S.-Israel Binational Science Foundation and the Benozyio Center for High Energy Physics ^d supported by the German-Israeli Foundation and the Israel Science Foundation ^e supported by the Italian National Institute for Nuclear Physics (INFN) ^f supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and its grants for Scientific Research ^g supported by the Korean Ministry of Education and Korea Science and Engineering Foundation ^h supported by the Netherlands Foundation for Research on Matter (FOM) ⁱ supported by the Polish State Committee for Scientific Research, grant no. 620/E-77/SPUB-M/DESY/P-03/DZ 247/2000-2002 ^j partially supported by the German Federal Ministry for Education and Research (BMBF) ^k supported by the Fund for Fundamental Research of Russian Ministry for Science and Education and by the German Federal Ministry for Education and Research (BMBF) ^l supported by the Spanish Ministry of Education and Science through funds provided by CICYT ^m supported by the Particle Physics and Astronomy Research Council, UK ⁿ supported by the US Department of Energy ^o supported by the US National Science Foundation ^p supported by the Polish State Committee for Scientific Research, grant no. 112/E-356/SPUB-M/DESY/P-03/DZ 301/2000-2002, 2 P03B 13922 ^q supported by the Polish State Committee for Scientific Research, grant no. 115/E-343/SPUB-M/DESY/P-03/DZ 121/2001-2002, 2 P03B 07022     

Physical states and BRST operators for higher-spin <Emphasis Type="Italic">W</Emphasis> strings

In this paper, we mainly investigate the W _2,s ^M ⊗ W _2,s ^L system, in which the matter and the Liouville subsystems generate the W _2,s ^M and W _2,s ^L algebras, respectively. We first give a brief discussion of the physical states for the corresponding W strings. The lower states are given by freezing the spin-2 and spin-s currents. Then, introducing two pairs of ghost-like fields, we give the realizations of the W _1,2,s algebras. Based on these linear realizations, the BRST operators for the W _2,s algebras are obtained. Finally, we construct new BRST charges of the Liouville system for the W _2,s ^L strings at the specific values of the central charges c: for the W _2,3^L algebra, c=−24 for the W _2,4^L algebra and for the W _2,6^L algebra, at which the corresponding W _2,s ^L algebras are singular.     

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     

<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.     

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.     

A Generalized Hypergeometric Function II. Asymptotics and <Emphasis Type="Italic">D</Emphasis><Subscript><Emphasis Type="Italic">4</Emphasis></Subscript> Symmetry

In previous work we introduced and studied a function that generalizes the hypergeometric function. In this paper we focus on a similarity-transformed function , with parameters ⁴ related to the couplings c⁴ by a shift depending on a ₊ , a _– . We show that the -function is invariant under all maps w(), with w in the Weyl group of type D ₄ . Choosing a ₊ , a _– positive and real, we obtain detailed information on the |Re v| asymptotics of the -function. In particular, we explicitly determine the leading asymptotics in terms of plane waves and the c-function that implements the similarity R.     

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.     

1/<Emphasis Type="Italic">N</Emphasis><Subscript><Emphasis Type="Italic">c</Emphasis></Subscript> countings in baryons

The 1/N _c -power countings for baryon decays and configuration mixings are determined by means of a nonrelativistic quark picture. Such countings are expected to be robust under changes in the quark masses and, therefore, valid as these become light. It is shown that excited baryons have natural widths of \(\mathcal{O}(N_c^0 )\). These dominant widths are due to the decays that proceed directly to the ground-state baryons, with cascade decays being suppressed to \(\mathcal{O}(1/N_c )\). Configuration mixings, defined as mixings between states belonging to different O(3) × SU(2N _f ) multiplets, are shown to be subleading in an expansion in \(1/\sqrt {N_c }\) when they involve the ground-state baryons, while the mixings between excited states can be \(\mathcal{O}(N_c^0 )\).