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The quantum fluctuations of the quark condensate are studied in a Nambu Jona-Lasinio model. Two Lorenz invariant regularizations are considered: a sharp 4-momentum cut-off and a soft gaussian regulator. The quantum fluctuations of the quark…

High Energy Physics - Phenomenology · Physics 2011-07-19 G. Ripka

The MILC collaboration's simulations with improved staggered quarks are being extended with runs at a lattice spacing of 0.06 fm with quark masses down to one tenth the strange quark mass. We give a brief introduction to these new…

High Energy Physics - Lattice · Physics 2010-11-15 C. Bernard , C. Davies , C. DeTar , Steven Gottlieb , U. M. Heller , J. E. Hetrick , L. Levkova , J. Osborn , D. B. Renner , R. Sugar , D. Toussaint

A summary of some recent results from lattice simulations is presented. These include first calculations of the strangeness magnetic moment of the nucleon, three new studies of the gluon propagator, flux tube attraction in U(1) gauge…

High Energy Physics - Phenomenology · Physics 2007-05-23 C. Morningstar

The scalar heavy quark content of the nucleon, ${\cal M}_q = \bra{N} m_q \bar q q \ket{N},$ is relevant for computing the interaction of dark matter candidates with ordinary matter, while ${\cal M}_s$ is important for predicting the…

High Energy Physics - Phenomenology · Physics 2009-11-10 Andrei Kryjevski

By combining the constraints of charge symmetry with new chiral extrapolation techniques and recent low mass lattice QCD simulations of the individual quark contributions to the magnetic moments of the nucleon octet, we obtain a precise…

High Energy Physics - Lattice · Physics 2008-11-26 D. B. Leinweber , S. Boinepalli , I. C. Cloet , A. W. Thomas , A. G. Williams , R. D. Young , J. M. Zanotti , J. B. Zhang

We report on our ongoing study of nucleon properties, the nucleon mass and the strange quark content (<N|ss|N>) in particular. These calculations are done on (2+1)-flavor Domain Wall Fermion (DWF) ensembles with Iwasaki gauge action with 2…

High Energy Physics - Lattice · Physics 2019-08-13 Chulwoo Jung

We compute the strangeness and light-quark contributions Delta s, Delta u and Delta d to the proton spin in nf=2 lattice QCD at a pion mass of about 285 MeV and at a lattice spacing a approx 0.073 fm, using the non-perturbatively improved…

The electromagnetic form factors provide important hints for the internal structure of the nucleon and continue to be of major interest for experimentalists. For an intermediate range of momentum transfers the form factors can be calculated…

The form factors of the nucleon provide key information on nucleon properties. When confronted with precisely measured observables from experiments, they serve as benchmark quantities for lattice calculations. On the other hand lattice…

High Energy Physics - Lattice · Physics 2021-12-03 Dalibor Djukanovic

A model combining vector meson dominance, $\omega - \phi$ mixing and a kaon cloud contribution is used to estimate the strangeness vector form factors of the nucleon in the momentum range of the planned measurements at MIT-Bates and CEBAF.…

High Energy Physics - Phenomenology · Physics 2009-09-25 Hilmar Forkel , Marina Nielsen , Xuemin Jin , Thomas D. Cohen

The charmed-strange meson masses are calculated on a quenched lattice QCD. The charm and strange quark propagators are calculated on the same lattice with the overlap fermion. $16^3\times 72$ lattice with Wilson gauge action at…

High Energy Physics - Lattice · Physics 2012-08-27 chi QCD Collaboration , S. J. Dong , K. F. Liu

We will discuss here an indirect lattice evaluation of the baryon axial singlet current matrix element. This quantity may be related to the fraction of nucleon spin carried by the quarks. The appropriate structure function has recently been…

High Energy Physics - Lattice · Physics 2011-04-15 R. Altmeyer , M. Goeckeler , R. Horsley , E. Laermann , G. Schierholz

We present the nucleon strange electromagnetic form factors using four lattice QCD ensembles with $N_f=2+1+1$ twisted mass clover-improved fermions and quark masses tuned to approximately their physical values. The four ensembles have…

We calculate several diagonal and non-diagonal fluctuations of conserved charges in a system of 2+1+1 quark flavors with physical masses, on a lattice with size $48^3\times12$. Higher order fluctuations at $\mu_B=0$ are obtained as…

The simplest models might describe the nucleon as 3 light quarks, but this description would be incomplete without inclusion of the sea of glue and q-qbar pairs which binds it. Early indications of a particularly large contribution from…

Nuclear Experiment · Physics 2011-10-18 Kent Paschke , Anthony Thomas , Robert Michaels , David Armstrong

We present results on the quark unpolarized, helicity and transversity parton distributions functions of the nucleon. We use the quasi-parton distribution approach within the lattice QCD framework and perform the computation using an…

High Energy Physics - Lattice · Physics 2021-09-22 Constantia Alexandrou , Martha Constantinou , Kyriakos Hadjiyiannakou , Karl Jansen , Floriano Manigrasso

By using lattice QCD computations we determine the sigma terms and strangeness content of all octet baryons by means of an application of the Hellmann-Feynman theorem. In addition to polynomial and rational expressions for the quark mass…

High Energy Physics - Lattice · Physics 2016-03-01 S. Durr , Z. Fodor , T. Hemmert , C. Hoelbling , J. Frison , S. D. Katz , S. Krieg , T. Kurth , L. Lellouch , T. Lippert , A. Portelli , A. Ramos , A. Schafer , K. K. Szabo

Motivated by the need for a solid state strange quark matter to better explain some observational phenomena, we discussed possibility of color singlet cluster formation in cold strange quark matter by a rough calculation following the…

Solar and Stellar Astrophysics · Physics 2009-12-11 Xuesen Na

The contribution of strange sea quarks to the proton mass and spin, as well as the related pion-nucleon sigma term, are briefly revisited, in the light of new experimental and lattice results. Also the predictions of chiral perturbation…

High Energy Physics - Phenomenology · Physics 2007-05-23 Michael D. Scadron , Frieder Kleefeld , George Rupp

I review recent studies of strangeness content in the nucleon pertaining to the flavor-singlet $g_A^0$, the $\bar{s}s$ matrix element and the strangeness electric and magnetic form factors $G_E^s(q^2)$ and $G_M^s(q^2)$, based on lattice QCD…

High Energy Physics - Phenomenology · Physics 2008-11-26 K. F. Liu
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