Thu·Aug 14, 2003Thursday·August 14, 2003

1. 01*

   Confining strings in representations with common $n$-ality

   Luigi Del Debbio🇮🇹 · Haralambos Panagopoulos🇨🇾 · Ettore Vicari🇮🇹

   We study the spectrum of confining strings in SU(3) pure gauge theory, by means of lattice Monte Carlo simulations, using torelon operators in different representations of the gauge group. Our results provide direct evidence that the string spectrum is according to predictions based on $n$-ality. Torelon correlations in the rank-2 symmetric channel appear to be well reproduced by a two-exponential picture, in which the lowest state is given by the fundamental string ${\sigma }_1=\sigma$, the heavier string state is such that the ratio ${\sigma }_2/{\sigma }_1$ is approximately given by the Casimir ratio $C_{\mathrm{sym}}/C_{\mathrm{f}}=5/2$, and the torelon has a much smaller overlap with the lighter fundamental string state.

   hep-latJHEP(2003)·29 citations
2. 02*

   Gluodynamics in External Field: A Test of the Dual Superconductor Picture

   M. N. Chernodub🇷🇺

   We study gluodynamics in an external Abelian electromagnetic field within the dual superconductor approach. We show that the SU(2) gluodynamics should possess a deconfining phase transition at zero temperature at certain value of the external field. A dual superconductor model for the SU(3) gauge theory in external field predicts a rich phase structure containing confinement, asymmetric confinement and deconfinement phases. These results can be used to check the validity of the dual superconductor description of gluodynamics in external fields. We also discuss the gauge-independence of the obtained results.

   hep-lathep-phhep-th0 citations
3. 03*

   Finite-Volume Partially-Quenched Two-Pion Amplitudes in the I=0 Channel

   C.-J.D. Lin🇬🇧 · G. Martinelli🇮🇹 · E. Pallante🇮🇹 · C.T. Sachrajda🇬🇧 · G. Villadoro🇮🇹

   We present a study of the finite-volume two-pion matrix elements and correlation functions of the I=0 scalar operator, in full and partially quenched QCD, at one-loop order in chiral perturbation theory. In partially quenched QCD, when the sea and valence light quark masses are not equal, the lack of unitarity leads to the same inconsistencies as in quenched QCD and the matrix elements cannot be determined. It is possible, however, to overcome this problem by requiring the masses of the valence and sea quarks to be equal for the u and d quarks while keeping the strange quark (s) quenched (or partially quenched), but only in the kinematic region where the two-pion energy is below the two-kaon threshold. Although our results are obtained at NLO in chiral perturbation theory, they are more general and are also valid for non-leptonic kaon decays (we also study the matrix elements of (8,1) operators, such as the QCD penguin operator Q6). We point out that even in full QCD, where any problems caused by the lack of unitarity are clearly absent, there are practical difficulties in general, caused by the fact that finite-volume energy eigenstates are linear combination of two-pion, two-kaon and two-eta states. Our work implies that extracting Delta I=1/2, K-->pipi decay amplitudes from simulations with m_s=m_{d,u} is not possible in partially quenched QCD (and is very difficult in full QCD).

   hep-lathep-phPLB(2004)·26 citations
4. 04*

   Lattice calculations of hadron properties

   Gunnar S. Bali🇬🇧

   Recent lattice studies of hadron properties, in particular of exotic states and charmonia are reviewed. Sea quark and quark mass effects are discussed as well as decays and mixing.

   hep-lathep-phnucl-thEPJA(2004)·35 citations
5. 05*

   Color superconductivity, Z_N flux tubes and monopole confinement in deformed N=2* super Yang-Mills theories

   Marco A. C. Kneipp🇧🇷

   We study the Z_N flux tubes and monopole confinement in deformed N=2* super Yang-Mills theories. In order to do that we consider an N=4 super Yang-Mills theory with an arbitrary gauge group G and add some N=2, N=1 and N=0 deformation terms. We analyze some possible vacuum solutions and phases of the theory, depending on the deformation terms which are added. In the Coulomb phase for the N=2* theory, G is broken to U(1)^r and the theory has monopole solutions. Then, by adding some deformation terms, the theory passes to the Higgs or color superconducting phase, in which G is broken to its center C_G. In this phase we construct the Z_N flux tubes ansatz and obtain the BPS string tension. We show that the monopole magnetic fluxes are linear integer combinations of the string fluxes and therefore the monopoles can become confined. Then, we obtain a bound for the threshold length of the string-breaking. We also show the possible formation of a confining system with 3 different monopoles for the SU(3) gauge group. Finally we show that the BPS string tensions of the theory satisfy the Casimir scaling law.

   ↳ hep-thhep-lathep-phPRD(2004)·48 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.