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Moments of the quark density, helicity, and transversity distributions are calculated in unquenched lattice QCD. Calculations of proton matrix elements of operators corresponding to these moments through the operator product expansion have…

We report a first principle lattice calculation of the pion electric polarizability $\alpha_\pi$ at the physical pion mass. First, we derive the master formula, which relates the pion polarizabilities with the position space hadronic…

High Energy Physics - Lattice · Physics 2022-01-06 Xu Feng , Taku Izubuchi , Luchang Jin , Maarten Golterman

Radiative processes, where a photon/neutrino is emitted as a result of a collision or decay of a particle, play a central role in atomic, nuclear and particle physics. Their rate is determined by certain off-diagonal matrix elements with…

Nuclear Theory · Physics 2022-09-22 Paulo F. Bedaque , Ratna Khadka , Gautam Rupak , Muhammad Yusf

A scheme to calculate the electric spin polarizability of the neutron, based on a four-point function approach to the background field method, is presented. The connected contributions to this spin polarizability are evaluated within a…

High Energy Physics - Lattice · Physics 2011-11-17 Michael Engelhardt

A recently developed numerical method for the calculation of derivatives of functions of general complex matrices, which can also be combined with implicit matrix function approximations such as Krylov-Ritz type algorithms, is presented. An…

High Energy Physics - Lattice · Physics 2016-11-02 M. Puhr , P. V. Buividovich

We combine constraints from analyticity with experimental electron-proton scattering data to determine the proton magnetic radius without model-dependent assumptions on the shape of the form factor. We also study the impact of including…

High Energy Physics - Phenomenology · Physics 2014-10-29 Zachary Epstein , Gil Paz , Joydeep Roy

We present an update on the status of the calculations of isovector and flavor-diagonal charges of the nucleon. The calculations of the isovector charges are being done using ten $2+1+1$-flavor HISQ ensembles generated by the MILC…

High Energy Physics - Lattice · Physics 2018-04-18 Rajan Gupta , Tanmoy Bhattacharya , Yong-Chull Jang , Huey-Wen Lin , Boram Yoon

We study thermodynamic properties and the electrical conductivity of dense hydrogen and deuterium using three methods: classical reactive Monte Carlo (REMC), direct path integral Monte Carlo (PIMC) and a quantum dynamics method in the…

Plasma Physics · Physics 2015-05-13 V. S. Filinov , P. R. Levashov , A. V. Boţan , M. Bonitz , V. E. Fortov

We calculate the electric dipole moment of the nucleon induced by the QCD theta term. We use the gradient flow to define the topological charge and use $N_f = 2+1$ flavors of dynamical quarks corresponding to pion masses of $700$, $570$,…

High Energy Physics - Lattice · Physics 2021-01-27 Jack Dragos , Thomas Luu , Andrea Shindler , Jordy de Vries , Ahmed Yousif

A calculational scheme for obtaining the electric polarizability of the neutron in lattice QCD with dynamical quarks is developed, using the background field approach. The scheme differs substantially from methods previously used in the…

High Energy Physics - Lattice · Physics 2008-11-26 Michael Engelhardt

Calculations of form factors in different forms of relativistic kinematics are presented. They involve the instant, front and point forms. In the two first cases, different kinematical conditions are considered while in the latter case,…

Nuclear Theory · Physics 2009-11-10 Bertrand Desplanques

Electromagnetic polarizabilities are important parameters for understanding the interaction between photons and hadrons. For pions these quantities are poorly constrained experimentally since they can only be measured indirectly. New…

High Energy Physics - Lattice · Physics 2016-02-17 Andrei Alexandru , Michael Lujan , Walter Freeman , Frank Lee

We present a model-independent calculation of hadron matrix elements for all dimension-six operators associated with baryon number violating processes using lattice QCD. The calculation is performed with the Wilson quark action in the…

In most simulations of nonrelativistic nuclear systems, the wave functions found solving the many-body Schr\"odinger equations describe the quantum-mechanical amplitudes of the nucleonic degrees of freedom. In those simulations the pionic…

Nuclear Theory · Physics 2018-10-01 Lucas Madeira , Alessandro Lovato , Francesco Pederiva , Kevin E. Schmidt

We determine within lattice QCD, the nucleon spin carried by valence and sea quarks, and gluons. The calculation is performed using an ensemble of gauge configurations with two degenerate light quarks with mass fixed to approximately…

High Energy Physics - Lattice · Physics 2017-11-21 C. Alexandrou , M. Constantinou , K. Hadjiyiannakou , K. Jansen , C. Kallidonis , G. Koutsou , A. Vaquero Avilés-Casco , C. Wiese

We present calculations of the magnetic moment and magnetic polarisability of the neutron from the background field method. The calculations are performed on $32^3\times64$ dynamical lattices generated by the PACS-CS collaboration and made…

High Energy Physics - Lattice · Physics 2012-12-11 Thomas Primer , Waseem Kamleh , Derek Leinweber , Matthias Burkardt

The magnetic polarisability is a fundamental property of hadrons, which provides insight into their structure in the low-energy regime. The pion magnetic polarisability is calculated using lattice QCD in the presence of background magnetic…

High Energy Physics - Lattice · Physics 2020-11-09 Ryan Bignell , Waseem Kamleh , Derek Leinweber

Neutrinoless double-beta ($0\nu\beta\beta$) decays provide an excellent probe for determining whether neutrinos are Dirac or Majorana fermions. The short-range matrix elements associated with the $\pi^- \to \pi^+ ee$ process contribute at…

The magnetic moment and magnetic polarisability of the neutron and proton are investigated using the uniform background-field method and lattice QCD. The results are calculated using 32^3 x 64 dynamical QCD lattices provided by the PACS-CS…

High Energy Physics - Lattice · Physics 2017-04-28 Ryan Bignell , Derek Leinweber , Waseem Kamleh , Matthias Burkardt

We extract the neutron electric dipole moment $\vert \vec{d}_N\vert$ within the lattice QCD formalism. We analyse one ensemble of $N_f=2+1+1$ twisted mass clover-improved fermions with lattice spacing of $a \simeq 0.08 \ {\rm fm}$ and…

High Energy Physics - Lattice · Physics 2021-03-17 C. Alexandrou , A. Athenodorou , K. Hadjiyiannakou , A. Todaro
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