Results for "S. Prelovsek"
total 163664took 0.12s
Quenched scalar meson correlator with Domain Wall FermionsSep 18 2002We study the singlet and non-singlet scalar-meson masses using domain wall fermions and the quenched approximation. The singlet mass is found to be smaller than the non-singlet mass and indicates that the lowest singlet meson state could be lighter than ... More $c\to uγ$ in the minimal supersymmetric standard modelDec 11 2000The minimal supersymmetric standard model (MSSM) with universal soft breaking terms has a negligible effect on the rare $c\to u\gamma$ decay rate. We therefore study a general model with non-universal soft breaking terms constrained by vacuum stability ... More Probing $c\to uγ$ in $B_c\to B_u^*γ$ decayMay 11 1999Flavour changing neutral current (FCNC) transitions $c\to u\gamma$ and $c\to ul^+l^-$ are very rare in the standard model and present an interesting probe for the physics beyond it. We study long distance contamination to these short distance processes ... More FCNC transition $c\to uγ$ in $B_c\to B_u^*γ$ decayNov 17 1999We propose the $B_c\to B_u^*\gamma$ decay as the most suitable probe for the flavour changing neutral transition $c\to u\gamma$. We estimate the short and long distance contributions to this decay within the standard model and we find them to be comparable; ... More Long distance contributions in $D \to V γ$ decaysJan 13 1998Oct 21 1998Using the factorization scheme for the nonleptonic $D \to V V_0$ weak amplitudes, we classify all diagrams which arise in $D \to V \gamma$ decays and calculate them with the help of the hybrid model which combines the heavy quark effective theory and ... More Operators for scattering of particles with spinOct 04 2016Operators for simulating the scattering of two particles with spin are constructed. Three methods are shown to give the consistent lattice operators for PN, PV, VN and NN scattering, where P, V and N denote pseudoscalar meson, vector meson and nucleon. ... More Lattice operators for scattering of particles with spinJul 22 2016Jan 30 2017We construct operators for simulating the scattering of two hadrons with spin on the lattice. Three methods are shown to give the consistent operators for PN, PV, VN and NN scattering, where P, V and N denote pseudoscalar, vector and nucleon. Explicit ... More Radiative decays of D mesonsAug 20 1998Oct 16 1998The short-distance contribution due to the $c\to u\gamma$ penguin as well as long-distance contributions are considered in an analysis of $D\to V\gamma$ decays, the latter being dominant. The matrix elements for nine $D\to V\gamma$ transitions are calculated ... More $B_sπ^+$ scattering and search for X(5568) with lattice QCDJul 11 2016We investigate $B_s\pi^+$ scattering in s-wave using lattice QCD in order to search for an exotic resonance X(5568) with flavor $\bar b s \bar d u$; such a state was recently reported by D0 but was not seen by LHCb. If X(5568) with $J^P=0^+$ exists, it ... More $B_sπ^+$ scattering and search for X(5568) with lattice QCDJul 11 2016Oct 11 2016We investigate $B_s\pi^+$ scattering in s-wave using lattice QCD in order to search for an exotic resonance X(5568) with flavor $\bar b s \bar d u$; such a state was recently reported by D0 but was not seen by LHCb. If X(5568) with $J^P=0^+$ exists, it ... More Vanishing Hall Constant in the Stripe Phase of CupratesFeb 22 2001The Hall constant R_H is considered for the stripe structures. In order to explain the vanishing of R_H in LNSCO at x = 1/8, we use the relation of R_H to the Drude weight D as well as direct numerical calculation, to obtain results within the t-J model, ... More Lattice operators for scattering of particles with spinJul 22 2016We construct operators for simulating the scattering of two hadrons with spin on the lattice. Three methods are shown to give the consistent operators for PN, PV, VN and NN scattering, where P, V and N denote pseudoscalar, vector and nucleon. Explicit ... More The rare decays of D mesonsAug 22 2002The flavor changing transitions in the c->u gamma, c->u gamma gamma and c->u l+ l- offer the possibility to search for new physics in the charm sector. We investigate dominant decay mechanisms in the radiative decays D->V gamma, D->P(V) l+ l-, D->gamma ... More Pion-nucleon scattering in the Roper channel from lattice QCDOct 05 2016Jan 31 2017We present a lattice QCD study of $N\pi$ scattering in the positive-parity nucleon channel, where the puzzling Roper resonance $N^*(1440)$ resides in experiment. The study is based on the PACS-CS ensemble of gauge configurations with $N_f=2+1$ Wilson-clover ... More Effective Field Theories in a Finite VolumeMay 10 2018In this talk I present the formalism we have used to analyze Lattice data on two meson systems by means of effective field theories. In particular I present the results obtained from a reanalysis of the lattice data on the $KD^{(*)}$ systems, where the ... More Taste breaking effects in scalar meson correlatorsOct 03 2006As a consistency check of the staggered-fermion fourth-root approximation, we analyze the a_0 and f_0 correlators, including the effects of two-meson taste-multiplet intermediate states. Rooted staggered chiral perturbation theory describes the contributions ... More Decay of rho and a1 mesons on the lattice using distillationNov 02 2011We extract the P-wave pi-pi phase shift for five values of pion relative momenta, which gives information on the rho resonance. The Breit-Wigner formula describes the pi-pi phase shift dependence nicely and we extract m(rho)=792(7)(8) MeV and the coupling ... More Anomalous scaling of conductivity in integrable fermion systemsMar 12 2004Jun 23 2004We analyze the high-temperature conductivity in one-dimensional integrable models of interacting fermions: the t-V model (anisotropic Heisenberg spin chain) and the Hubbard model, at half-filling in the regime corresponding to insulating ground state. ... More Top Quark Production at TeV Energies as a Potential SUSY DetectorApr 24 2001We consider the process of top-antitop production from electron-positron annihilation, for c. m. energies in the few TeV regime, in the MSSM theoretical framework. We show that, at the one loop level, the \underline{slopes} of a number of observable quantities ... More Pion-nucleon scattering in the Roper channel from lattice QCDOct 05 2016We present a lattice QCD study of $N\pi$ scattering in the positive-parity nucleon channel, where the puzzling Roper resonance $N^*(1440)$ resides in experiment. The study is based on the PACS-CS ensemble of gauge configurations with $N_f=2+1$ Wilson-clover ... More Lattice studies of charmonia and exoticsAug 28 2015The lattice QCD simulations of charmonia and exotic charmonium-like states are reviewed. I report on the first exploratory simulation of charmonium resonances above open charm threshold which takes into account the strong decay. The puzzles related to ... More Scalar mesons on the LatticeNov 09 2005The simulations of the light scalar mesons on the lattice are presented at the introductory level. The methods for determining the scalar meson masses are described. The problems related to some of these methods are presented and their solutions discussed. ... More Hadron SpectroscopyNov 03 2014Recent results on the hadron spectroscopy from lattice QCD are reviewed with emphasis on the meson sector and in particular on quarkonium-like $XYZ$ states. I report on the first rigorous treatment of the near-threshold states $X(3872)$ and $D_s^0(2317)$, ... More Electron Green's Function in the Planar t-J ModelNov 29 1996The electron Green's functions $G({\bf k},\omega)$ within the t-J model and in the regime of intermediate doping is studied analytically using equations of motion for projected fermionic operators and the decoupling of the self energy into the single-particle ... More Hall effect of charge carriers in a correlated systemSep 30 1996The dynamical Hall response in a correlated electronic system is analysed within the linear response theory for tight binding models. At $T=0$ the d.c. Hall constant for a single quasiparticle is expressed explicitly via the charge stiffness, and a semiclassical ... More Probing new physics in rare charm processesApr 17 2001We explore the sensitivity of the flavour changing neutral currents among c and u quarks in the context of the Minimal Supersymmetric Standard Model. The standard model rate for c->u gamma can be enhanced by up to two orders of magnitudes in general MSSM, ... More Exotic and conventional mesons from latticeSep 28 2014Recent results on meson spectroscopy from lattice QCD are reviewed. The emphasis is on interesting states near thresholds like $Z_c^+(3900)$, $X(3872)$ and $D_{s0}^*(2317)$. Another focus is on the meson resonances in light, strange and charm sector, ... More Weak decays of Heavy mesonsOct 11 2000I explore the possibility of using heavy meson decays as probes for flavour changing neutral transitions (FCNC) $c\to u\gamma$ and $c\to ul^+l^-$. In the standard model, these are the most frequent FCN transitions among the quarks with charge $2/3e_0$. ... More Normal State Properties of Cuprates: t-J Model vs. ExperimentJul 03 2000We discuss some recent results for the properties of doped antiferromagnets, obtained within the planar t-J model mainly by the finite-temperature Lanczos method, with the emphasis on the comparison with experimental results in cuprates. Among the thermodynamic ... More Hadron spectroscopy and interactions from lattice QCDSep 10 2016Sep 23 2016Lattice QCD approach to study the hadronic resonances and exotic hadrons is described at an introductory level. The main challenge is that these states decay strongly via one or more decay channels, and they often lie near thersholds. Specific results ... More Lattice QCD review of charmonium and open-charm spectroscopyOct 16 2013Oct 18 2013Lattice QCD results on the spectroscopy of charmonium(like) states and open charm mesons are reviewed. Near-threshold states X(3872) and D_{s0}^*(2317) were treated rigorously for the first time and the searches for Z_c^+(3900), X(4140) and $cc\bar u\bar ... More Charmonium resonances on the latticeJun 07 2018The nature of resonances and excited states near decay thresholds is encoded in scattering amplitudes, which can be extracted from single-particle and multiparticle correlators in finite volumes. Lattice calculations have only recently reached the precision ... More Charmonia in moving framesOct 17 2017Lattice simulation of charmonium resonances with non-zero momentum provides additional information on the two-meson scattering matrices. However, the reduced rotational symmetry in a moving frame renders a number of states with different $J^P$ in the ... More Searching for tetraquarks on the latticeFeb 01 2010We address the question whether the lightest scalar mesons sigma and kappa are tetraquarks. We present a search for possible light tetraquark states with J^PC=0^++ and I=0, 1/2, 3/2, 2 in the dynamical and the quenched lattice simulations using tetraquark ... More Spectroscopy of light tetraquark statesOct 15 2009We address the question whether the lightest scalar mesons sigma and kappa are tetraquarks, as is strongly supported by many phenomenological studies. We present a search for possible light tetraquark states with J^PC=0^++ and I=0, 1/2, 3/2, 2 on the ... More Hadronic Resonances in Lattice QCDApr 08 2013I discuss how masses and widths of hadron resonances are extracted from lattice QCD. Recent lattice results on the light, strange and charm meson resonances are reviewed. Their properties are revealed by simulating the corresponding scattering channels ... More Ground State and Finite Temperature Lanczos MethodsNov 25 2011The present review will focus on recent development of exact-diagonali- zation (ED) methods that use Lanczos algorithm to transform large sparse matrices onto the tridiagonal form. We begin with a review of basic principles of the Lanczos method for computing ... More Effects of Littlest Higgs model in rare D meson decaysNov 04 2005Feb 23 2006A tree-level flavor changing neutral current in the up-like quark sector appears in one of the variations of the Littlest Higgs model. We investigate the effects of this coupling in the D+ -> pi+ l+ l- and D0 -> rho0 l+ l- decays, which are the most appropriate ... More Pseudogap and the Fermi surface in the t-J modelSep 12 2001We calculate spectral functions within the t-J model as relevant to cuprates in the regime from low to optimum doping. On the basis of equations of motion for projected operators an effective spin-fermion coupling is derived. The self energy due to short-wavelength ... More Spectral functions and pseudogap in the t-J modelNov 06 2000Feb 28 2001We calculate spectral functions within the t-J model as relevant to cuprates in the regime from low to optimum doping. On the basis of equations of motion for projected operators an effective spin-fermion coupling is derived. The self energy due to short-wavelength ... More Search for Z_c^+(3900) in the 1^+- channel on the latticeAug 09 2013Oct 16 2013Recently three experiments reported a discovery of manifestly exotic Z_c^+(3900) in the decay to J/psi pi+, while J and P are experimentally unknown. We search for this state on the lattice by simulating the channel with J^PC=1^+- and I=1, and we do not ... More Symmetries of spatial meson correlators in high temperature QCDFeb 08 2019Jun 12 2019Based on a complete set of $J = 0$ and $J=1$ spatial isovector correlation functions calculated with $N_F = 2$ domain wall fermions we identify an intermediate temperature regime of $T \sim 220 - 500$ MeV ($1.2T_c$--$2.8T_c$), where chiral symmetry is ... More Search for New Physics in Rare D DecaysOct 03 2006In many extensions of the standard model an additional up-like heavy quark appears. Its appearance induces flavour changing neutral current transition in the up-quark region at the tree level. We investigate possible effects of these models in the c->u ... More Luttinger sum rule for finite systems of correlated electronsSep 12 2006Nov 28 2006The validity of the Luttinger sum rule is considered for finite systems of interacting electrons, where the Fermi volume is determined by location of zeroes of Green's function. It is shown that the sum rule in the paramagnetic state is evidently violated ... More Pseudo gap in the density of states in cupratesJan 21 2000In the framework of the t-J model for cuprates we analyze the development of a pseudo gap in the density of states (DOS), which at low doping starts to emerge for temperatures T<J and persists up to the optimum doping. The analysis is based on numerical ... More A lattice study of light scalar tetraquarksOct 09 2008The observed mass pattern of scalar resonances below 1 GeV gives preference to the tetraquark assignment over the conventional $\bar qq$ assignment for these states. We present a search for tetraquarks with isospins 0, 1/2, 1 in lattice QCD, where the ... More Freezing of spin dynamics in underdoped cupratesFeb 03 2009The Mori's memory function approach to spin dynamics in doped antiferromagnetic insulator combined with the assumption of temperature independent static spin correlations and constant collective mode damping leads to w/T scaling in a broad range. The ... More Transport of Strongly Correlated ElectronsMar 14 2002Lectures deal with the theory of electronic transport, in particular with the electrical conductivity, in systems dominated by strong electron-electron repulsion. The concept of charge stiffness is introduced to distinguish conductors and insulators at ... More Spin-fluctuation mechanism of superconductivityJun 28 2005Normal and superconducting state spectral properties of cuprates are theoretically described within the extended t-J model. The method is based on the equations of motion for projected fermionic operators and the mode-coupling approximation for the self-energy ... More Anomalous Spin Dynamics in Doped Quantum AntiferromagnetsOct 24 1994Finite-temperature spin dynamics in planar t-J model is studied using the method based on the Lanczos diagonalization of small systems. Dynamical spin structure factor at moderate dopings shows the coexistence of free-fermion-like and spin-fluctuation ... More Reactive Hall constant of Strongly Correlated ElectronsJul 12 2001The zero-temperature Hall response within tight-binding models of correlated electrons is studied. Using the linear response theory and a linearization in the magnetic field B, a general relation for the reactive (zero frequency) Hall constant in the ... More Charge Dynamics in the Planar t-J ModelDec 28 1994The finite-temperature optical conductivity $\sigma(\omega)$ in the planar $t-J$ model is analysed using recently introduced numerical method based on the Lanczos diagonalization of small systems (up to 20 sites), as well as by analytical approaches, ... More Spectral properties of the planar t-J modelJul 19 1996The single-particle spectral functions $A({\bf k},\omega)$ and self-energies $\Sigma({\bf k},\omega)$ are calculated within the $t-J$ model using the finite-temperature Lanczos method for small systems. A remarkable asymmetry between the electron and ... More Symmetries of spatial meson correlators in high temperature QCDFeb 08 2019Based on a complete set of $J = 0$ and $J=1$ spatial isovector correlation functions calculated with $N_F = 2$ domain wall fermions we identify an intermediate temperature regime of $T \sim 250 - 550$ MeV where chiral symmetry is restored but the correlators ... More Transport in one dimensional quantum systemsApr 28 2003May 05 2003In this Chapter, we present recent theoretical developments on the finite temperature transport of one dimensional electronic and magnetic quantum systems as described by a variety of prototype models. In particular, we discuss the unconventional transport ... More Finite-temperature properties of doped antiferromagnetsMar 26 1998We review recent results for the properties of doped antiferromagnets, obtained by the numerical analysis of the planar t-J model using the novel finite-temperature Lanczos method for small correlated systems. First we shortly summarize our present understanding ... More Raman Response in Doped AntiferromagnetsJan 29 1996Mar 07 1996The resonant part of the $B_{1g}$ electronic Raman scattering response is calculated within the $t-J$ model on a planar lattice as a function of temperature and hole doping, using a finite-temperature diagonalization method for small systems. Results, ... More