Wed·Oct 5, 2005Wednesday·October 5, 2005

1. 01*

   Pionic couplings (g^ and g~) in the static heavy quark limit

   D.Becirevic🇫🇷 · B.Blossier🇫🇷 · Ph.Boucaud🇫🇷 · J.P.Leroy🇫🇷 · A.LeYaouanc🇫🇷 · O.Pene🇫🇷

   The couplings between the soft pion and the doublet of heavy-light mesons are basic parameters of the ChPT approach to the heavy-light systems. We compute the unquenched (Nf=2) values of two such couplings in the static heavy quark limit: (1) g^, coupling to the lowest doublet of heavy-light mesons, and (2) g~, coupling to the first orbital excitations. A brief description of the calculation together with a short discussion of the results is presented.

   hep-lathep-phPoS(2006)·15 citations
2. 02*

   K_l3 form factor with two-flavors of dynamical domain-wall quarks

   C.Dawson🇺🇸 · T.Izubuchi🇺🇸 · T.Kaneko🇯🇵 · S.Sasaki🇯🇵 · A.Soni🇺🇸

   We report on our calculation of K \to \pi vector form factor by numerical simulations of two-flavor QCD on a 16^3x32x12 lattice at a \simeq 0.12 fm using domain-wall quarks and DBW2 glue. Our preliminary result at a single sea quark mass correponding to m_PS/m_V \simeq 0.53 shows a good agreement with previous estimate in quenched QCD and that from a phenomenological model.

   hep-latPoS(2006)·28 citations
3. 03*

   $K\to \pi \pi$ from electroweak penguins in $N_f=2$ domain-wall QCD

   Jun Noaki🇬🇧

   We present the calculation of $K\to \pi \pi$ matrix elements of electroweak penguin operators {\it i.e.} $Q_7$ and $Q_8$. In the numerical simulation, we use the gauge configurations generated by the combination of $N_f=2$ domain-wall fermions and DBW2 gauge action. From $K\to \pi$ and $K\to 0$ matrix elements on the lattice, we construct $K\to \pi \pi$ matrix elements at next-to-leading order in the chiral expansion by using recent analytic results. Renormalization factor of these matrix elements are obtained by the non-perturbative renormalization technique in RI/MOM scheme. Brief discussion based on our results are made as well as a comparison with previous works.

   hep-latPoS(2006)·6 citations
4. 04*

   Geometry of three dimensional vacuum domains in four dimensional SU(2) gluodynamics

   A.V. Kovalenko🇷🇺 · M.I. Polikarpov🇷🇺 · S.N. Syritsyn🇷🇺 · V.I.Zakharov🇩🇪

   We review briefly recent results of lattice simulations on 3d domains in the vacuum state of SU(2) gluodynamics. The defects are defined as unification of all the negative links in central projection under condition that the total number of negative links is minimized. In the continuum limit, negative links correspond, generally speaking to singular fields. The data indicate that total volume of the defects scales in physical units. We consider also correlator of negative links. The correlator scales in physical units as well, within the error bars. A new observation reported here is a strong anisotropy of the correlator.

   hep-latPoS(2006)·1 citation
5. 05*

   Heavy Quark Diffusion and Lattice Correlators

   P. Petreczky🇺🇸 · K. Petrov🇺🇸 · D. Teaney🇺🇸 · A. Velytsky🇺🇸

   We study charmonia correlators at finite temperature. We analyze to what extent heavy quarkonia correlators are sensitive to the effect of heavy quark transport and whether it is possible to constrain the heavy quark diffusion constant by lattice calculations. Preliminary lattice calculations of quarkonia correlators performed on anisotropic lattices show that they are sensitive to the effect of heavy quark transport, but much detailed calculations are required to constrain the value of the heavy quark diffusion constant.

   hep-lathep-phPoS(2006)·9 citations
6. 06*

   Finite-volume effects in moving frames

   Changhoan Kim🇬🇧 · Chris T. Sachrajda🇬🇧 · Stephen R. Sharpe🇺🇸

   We determine the quantization condition for the energy levels of two interacting particles in a finite box in a ``moving frame'', i.e. one in which the total momentum of pions is non-zero. This condition is valid up to corrections which fall exponentially withe the box size, and holds only below the inelastic threshold. It is derived using field theoretic methods, using a generalization of previous summation formulae relating sums and integrals over momenta. The result agrees with that obtained earlier by Rummakainen and Gottlieb using a relativistic quantum mechanical approach. Technically, we expand the finite-volume four-point Green function in terms of the infinite-volume Bethe-Salpeter kernel, and determine the position of the poles. The final result is written in terms of the two-pion scattering phase shift. Our result can be used to facilitate the determination of the scattering phase shift, and can be used to generalize the Lellouch-Lüscher formula relating finite-volume two-particle matrix elements to those in infinite volume.

   hep-latPoS(2006)·14 citations
7. 07*

   3-point functions from twisted mass lattice QCD at small quark masses

   S. Capitani🇦🇹 · K. Jansen🇩🇪 · M. Papinutto🇩🇪 · A. Shindler🇩🇪 · I. Wetzorke🇩🇪 · C. Urbach🇩🇪

   We show at the example of the matrix element between pion states of a twist-2, non-singlet operator that Wilson twisted mass fermions allow to compute this phenomenologically relevant quantitiy at small pseudo scalar masses of O(270 MeV). In the quenched approximation, we investigate the scaling behaviour of this observable that is derived from a 3-point function by applying two definitions of the critical mass and find a scaling compatible with the expected O(a^2) behaviour in both cases. A combined continuum extrapolations allows to obtain reliable results at small pion masses, which previously could not be explored by lattice QCD simulations.

   hep-latPoS(2006)·1 citation
8. 08*

   Ginsparg-Wilson Pions Scattering in a Sea of Staggered Quarks

   Jiunn-Wei Chen🇹🇼 · Donal O'Connell🇺🇸 · Ruth S. Van de Water🇺🇸 · Andre Walker-Loud🇺🇸

   We calculate isospin 2 pion-pion scattering in chiral perturbation theory for a partially quenched, mixed action theory with Ginsparg-Wilson valence quarks and staggered sea quarks. We point out that for some scattering channels, the power-law volume dependence of two pion states in nonunitary theories such as partially quenched or mixed action QCD is identical to that of QCD. Thus one can extract infinite volume scattering parameters from mixed action simulations. We then determine the scattering length for both 2 and 2+1 sea quarks in the isospin limit. The scattering length, when expressed in terms of the pion mass and the decay constant measured on the lattice, has no contributions from mixed valence-sea mesons, thus it does not depend upon the parameter, C_Mix, that appears in the chiral Lagrangian of the mixed theory. In addition, the contributions which nominally arise from operators appearing in the mixed action O(a^2 m_q) Lagrangian exactly cancel when the scattering length is written in this form. This is in contrast to the scattering length expressed in terms of the bare parameters of the chiral Lagrangian, which explicitly exhibits all the sicknesses and lattice spacing dependence allowed by a partially quenched mixed action theory. These results hold for both 2 and 2+1 flavors of sea quarks.

   hep-lathep-phnucl-thPRD(2006)·68 citations
9. 09*

   Pseudo-epsilon expansion and the two-dimensional Ising model

   A.I. Sokolov🇷🇺

   Starting from the five-loop renormalization-group expansions for the two-dimensional Euclidean scalar \phi^4 field theory (field-theoretical version of two-dimensional Ising model), pseudo-\epsilon expansions for the Wilson fixed point coordinate g*, critical exponents, and the sextic effective coupling constant g_6 are obtained. Pseudo-\epsilon expansions for g*, inverse susceptibility exponent \gamma, and g_6 are found to possess a remarkable property - higher-order terms in these expansions turn out to be so small that accurate enough numerical estimates can be obtained using simple Pade approximants, i. e. without addressing resummation procedures based upon the Borel transformation.

   ↳ cond-mat.stat-mechhep-lathep-phhep-thFiz.Tverd.Tela(2005)·12 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.