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Related papers: Rationale for UV-filtered clover fermions

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We describe a way to optimize the chiral behavior of Wilson-type lattice fermion actions by studying the low energy real eigenmodes of the Dirac operator. We find a candidate action, the clover action with fat links with a tuned clover…

High Energy Physics - Lattice · Physics 2007-05-23 Thomas DeGrand , Anna Hasenfratz , Tamás G. Kovács

We extend to the clover improved lattice formulation of QCD the resummation of cactus diagrams, i.e. a certain class of tadpole-like gauge invariant diagrams. Cactus resummation yields an improved perturbative expansion. We apply it to the…

High Energy Physics - Lattice · Physics 2009-10-31 H. Panagopoulos , E. Vicari

One-loop corrections to the fermion rest mass M_1, wave function renormalization Z_2 and speed of light renormalization C_0 are presented for lattice actions that combine improved glue with clover or D234 quark actions and keep the temporal…

High Energy Physics - Lattice · Physics 2009-10-31 Stefan Groote , Junko Shigemitsu

Using non-perturbative techniques we have found the renormalisation factor, Z, in the RI-MOM scheme for quark bilinear operators in quenched QCD. We worked with overlap fermions using the Luescher-Weisz gauge action. Our calculation was…

High Energy Physics - Lattice · Physics 2016-09-01 M. Gürtler , R. Horsley , P. E. L. Rakow , C. J. Roberts , G. Schierholz , T. Streuer

We study exceptional modes of both the Wilson and the clover action in order to understand why quenched clover spectroscopy suffers so severely from exceptional configurations. We show that, in contrast to the case of the Wilson action, a…

High Energy Physics - Lattice · Physics 2015-06-25 T. DeGrand , A. Hasenfratz , T. G. Kovacs

We calculate the perturbative value of the free energy in QCD on the lattice. This quantity is directly related to the average plaquette. Our calculation is done to 3 loops using the clover action for fermions; the results are presented for…

High Energy Physics - Lattice · Physics 2009-11-10 A. Athenodorou , H. Panagopoulos , A. Tsapalis

We study the finite supersymmetric loop corrections to fermion masses and mixing matrices in the generic MSSM. In this context the effects of non-decoupling chirally-enhanced self-energies are studied beyond leading order in perturbation…

High Energy Physics - Phenomenology · Physics 2015-03-13 Andreas Crivellin , Jennifer Girrbach

In this work we calculate the corrections to the amputated Green's functions of 4-fermion operators, in 1-loop Lattice Perturbation theory. One of the novel aspects of our calculations is that they are carried out to O(a^2) (a: lattice…

We present a lattice-QCD based analysis of the nucleon sigma terms using gauge ensembles with $N_f = 2 + 1$ flavors of ${\cal O}(a)$-improved Wilson fermions, with a complete error budget concerning excited-state contaminations, the chiral…

High Energy Physics - Lattice · Physics 2024-01-17 Andria Agadjanov , Dalibor Djukanovic , Georg von Hippel , Harvey B. Meyer , Konstantin Ottnad , Hartmut Wittig

Minimally doubled fermions have been proposed as a cost-effective realization of chiral symmetry at non-zero lattice spacing. Using lattice perturbation theory at one loop, we study their renormalization properties. Specifically, we…

High Energy Physics - Lattice · Physics 2015-05-13 Stefano Capitani , Johannes Weber , Hartmut Wittig

We present results of quenched $SU(3)$ hadron spectroscopy comparing $\order(a)$ improved Wilson (Clover) fermions with conventional Wilson fermions. The configurations were generated using an $\order(a^2)$ improved 6-link $SU(3)$ pure…

High Energy Physics - Lattice · Physics 2010-01-18 Sara Collins , Robert G. Edwards , Urs M. Heller , John Sloan

For Wilson and clover fermions traditional formulations of the axial vector current do not respect the continuum Ward identity which relates the divergence of that current to the pseudoscalar density. Here we propose to use a point-split or…

High Energy Physics - Lattice · Physics 2015-11-18 R. Horsley , Y. Nakamura , H. Perlt , P. E. L. Rakow , G. Schierholz , A. Schiller , J. M. Zanotti

We systematically examine various proposals which aim at increasing the accuracy in the determination of the renormalization of two-fermion lattice operators. We concentrate on three finite quantities which are particularly suitable for our…

High Energy Physics - Lattice · Physics 2011-09-13 M. Crisafulli , V. Lubicz , A. Vladikas

We present results for the renormalization of gauge invariant nonlocal fermion operators which contain a Wilson line, to one loop level in lattice perturbation theory. Our calculations have been performed for Wilson/clover fermions and a…

High Energy Physics - Lattice · Physics 2018-04-18 M. Constantinou , H. Panagopoulos

We present the light-flavor quark masses and low energy constants using the 2+1 flavor full-QCD ensembles with stout smeared clover fermion action and Symanzik gauge actions. Both the fermion and gauge actions are tadpole improved…

High Energy Physics - Lattice · Physics 2024-01-09 Zhi-Cheng Hu , Bo-Lun Hu , Ji-Hao Wang , Ming Gong , Liuming Liu , Peng Sun , Wei Sun , Wei Wang , Yi-Bo Yang , Dian-Jun Zhao

We calculate corrections to the fermion propagator and to the Green's functions of all fermion bilinear operators of the form $\bar\Psi \Gamma \Psi$, to one-loop in perturbation theory. We employ the Wilson/clover action for fermions and a…

High Energy Physics - Lattice · Physics 2010-08-11 M. Constantinou , V. Lubicz , H. Panagopoulos , F. Stylianou

We compute the O(g^2) contribution to the thermodynamic pressure for Wilson fermions in the standard, the twisted mass, and clover improved formulation in lattice perturbation theory, including finite mass effects. We compare the continuum…

High Energy Physics - Lattice · Physics 2010-05-28 Owe Philipsen , Lars Zeidlewicz

A compact general integral formula is derived from which the fermionic contribution to the one-loop coefficient in the perturbative expansion of the MSbar coupling in powers of the bare lattice coupling can be extracted. It is seen to…

High Energy Physics - Lattice · Physics 2008-11-26 David H. Adams

We present the non-forward quark matrix elements of operators with one and two covariant derivatives needed for the renormalisation of the first and second moments of generalised parton distributions in one-loop lattice perturbation theory…

High Energy Physics - Lattice · Physics 2008-11-26 M. Gockeler , R. Horsley , H. Perlt , P. E. L. Rakow , A. Schaefer , G. Schierholz , A. Schiller

While the standard model is the most successfully theory to describe all interactions and constituents in elementary particle physics, it has been constantly examined for over four decades. Weak decays of charm quarks can measure the…

High Energy Physics - Lattice · Physics 2022-01-26 Qi-An Zhang , Jun Hua , Fei Huang , Renbo Li , Yuanyuan Li , Cai-Dian Lu , Peng Sun , Wei Sun , Wei Wang , Yi-Bo Yang