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It has been proposed that partially quenched chiral perturbation theory can be used together with partially quenched lattice QCD to determine the low-energy constants of real QCD. We point out a complication of this approach and show how it…

High Energy Physics - Lattice · Physics 2009-11-10 Stephen R. Sharpe , Ruth S. Van de Water

We study the properties of the B-->pi and B-->K transition form factors in partially quenched QCD by using the approach of partially quenched chiral perturbation theory combined with the static heavy quark limit. We show that the form…

High Energy Physics - Lattice · Physics 2014-11-17 Damir Becirevic , Sasa Prelovsek , Jure Zupan

We develop quenched chiral perturbation theory for vector mesons made of light quarks, in the limit where the vector meson masses are much larger than the pion mass. We use this theory to extract the leading nonanalytic dependence of the…

High Energy Physics - Phenomenology · Physics 2009-10-30 Michael Booth , George Chiladze , Adam F. Falk

In the calculation of non-leptonic weak decay rates, a "mismatch" arises when the QCD evolution of the relevant weak hamiltonian down to hadronic scales is performed in unquenched QCD, but the hadronic matrix elements are then computed in…

High Energy Physics - Lattice · Physics 2010-02-03 Maarten Golterman , Elisabetta Pallante

We discuss the importance of using partially quenched theories with three degenerate quarks for extrapolating to QCD, and present some relevant results from chiral perturbation theory.

High Energy Physics - Lattice · Physics 2015-06-25 S. Sharpe , N. Shoresh

In this talk, I first motivate the use of Chiral Perturbation Theory in the context of Lattice QCD. In particular, I explain how partially quenched QCD, which has, in general, unequal valence- and sea-quark masses, can be used to obtain…

High Energy Physics - Phenomenology · Physics 2017-08-23 Maarten Golterman

It has been widely assumed that partially quenched chiral perturbation theory is the correct low-energy effective theory for partially quenched QCD. Here we present arguments supporting this assumption. First, we show that, for partially…

High Energy Physics - Lattice · Physics 2015-06-15 Claude Bernard , Maarten Golterman

We study meson loop corrections to the baryon magnetic moments starting from a QCD-based quark model derived earlier in a quenched approximation to QCD. The model reproduces the standard quark model with extra corrections for the binding of…

High Energy Physics - Phenomenology · Physics 2009-10-31 Phuoc Ha , Loyal Durand

A summary of recent progress in Chiral Perturbation Theory (ChPT) at the two-loop level is given. A short introduction to ChPT is included, along with an explanation of the usefulness of developing ChPT for partially quenched QCD. Further,…

High Energy Physics - Phenomenology · Physics 2008-11-26 Johan Bijnens , Niclas Danielsson , Timo A. Lahde

We use one-loop chiral perturbation theory (ChPT) to compare lattice results for the K+ to pi+ pi0 decay amplitude with the experimental value. Three systematic effects: quenching, finite-volume effects, and the use of unphysical values of…

High Energy Physics - Lattice · Physics 2009-10-30 Maarten Golterman , Ka Chun Leung

We review recent progress in the understanding of low-energy baryon structure by means of chiral perturbation theory. In particular, we discuss the application of this formalism to the description of the quark mass dependence of recent…

High Energy Physics - Lattice · Physics 2010-11-15 J. Martin Camalich , L. S. Geng , M. J. Vicente Vacas

We formulate quenched chiral perturbation theory for heavy-light mesons coupled to pions, and calculate the one-loop chiral logarithmic corrections to $f_B$, $f_{B_{s}}$, $B_B$ and $B_{B_{s}}$. We also calculate these corrections for…

High Energy Physics - Lattice · Physics 2009-10-28 Stephen R. Sharpe , Yan Zhang

Heavy-baryon chiral perturbation theory (ChPT) at one loop fails in relating the pion-nucleon amplitude in the physical region and for subthreshold kinematics due to loop effects enhanced by large low-energy constants. Studying the chiral…

Nuclear Theory · Physics 2017-05-01 D. Siemens , J. Ruiz de Elvira , E. Epelbaum , M. Hoferichter , H. Krebs , B. Kubis , U. -G. Meißner

The chiral limit of finite-volume QCD is the $\epsilon$-regime of the theory. We discuss how this regime can be used for determining low-energy observables of QCD by means of comparisons between lattice simulations and quenched and…

High Energy Physics - Lattice · Physics 2016-09-01 P. H. Damgaard

We extend the chiral Lagrangian with heavy quark-diquark symmetry to quenched and partially quenched theories. These theories are used to derive formulae for the chiral extrapolation of masses and hyperfine splittings of doubly heavy…

High Energy Physics - Lattice · Physics 2014-11-17 Thomas Mehen , Brian C. Tiburzi

We extend to quenched QCD an earlier investigation of the chiral structure of the masses of the nucleon and the delta in lattice simulations of full QCD. Even after including the meson-loop self-energies which give rise to the leading and…

High Energy Physics - Lattice · Physics 2010-02-17 R. D. Young , D. B. Leinweber , A. W. Thomas , S. V. Wright

The quark mass dependence of meson masses and decay constants in N_f=2 QCD is studied at a fixed gauge coupling with different dynamical quark masses. Partially Quenched Wilson Chiral Perturbation Theory (PQWchiPT) is applied to obtain the…

High Energy Physics - Lattice · Physics 2009-11-10 q Collaboration , F. Farchioni , I. Montvay , E. Scholz

We analyze the chiral behavior of the hadron spectrum obtained with quenched Wilson fermions on 170 $32^3 \times 64$ lattices at $\beta = 6.0$. We calculate masses of hadrons composed of both degenerate and non-degenerate quarks. We reduce…

High Energy Physics - Lattice · Physics 2007-05-23 Tanmoy Bhattacharya , Rajan Gupta , Stephen Sharpe

We extend a technique for the chiral extrapolation of hadron masses calculated with dynamical fermions to those generated by quenched simulations. The method ensures the correct leading and next-to-leading non-analytic behaviour for either…

High Energy Physics - Lattice · Physics 2007-05-23 R. D. Young , D. B. Leinweber , A. W. Thomas , S. V. Wright

Heavy quark effective theory can be used to calculate the values of the semileptonic B^(*) -> D^(*) decays in the limit that the heavy quark masses are infinite. We calculate the lowest order chiral corrections, which are of O(1/M^2), from…

High Energy Physics - Lattice · Physics 2009-11-07 Daniel Arndt