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Related papers: Dynamical QCD simulation with theta terms

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One of the yet unsolved questions of QCD in the context of the Standard Model is to explain the strong CP problem. A way to look for a better understanding of it is to investigate the theory in the presence of a non-zero topological theta…

High Energy Physics - Lattice · Physics 2014-11-05 Lorenzo Bongiovanni , Gert Aarts , Erhard Seiler , Denes Sexty

We discuss a possibility that the Neutron Electric Dipole Moment (NEDM) can be calculated in lattice QCD simulations in the presence of the CP violating $\theta$ term. In this paper we measure the energy difference between spin-up and…

High Energy Physics - Lattice · Physics 2008-11-26 E. Shintani , S. Aoki , N. Ishizuka , K. Kanaya , Y. Kikukawa , Y. Kuramashi , M. Okawa , A. Ukawa , T. Yoshié

We reexamine the estimate of the neutron Electric Dipole Moment (NEDM) from chiral and QCD spectral sum rules (QSSR) approaches. In the former, we evaluate the pion mass corrections which are about 5% of the leading Log. results. However,…

High Energy Physics - Phenomenology · Physics 2008-11-26 Stephan Narison

In this chapter we introduce the $\theta$-dependence and the topological properties of QCD, features of the strongly interacting sector which give rise to the strong CP problem in the more general context of the Standard Model of particle…

High Energy Physics - Lattice · Physics 2026-03-27 Claudio Bonanno , Claudio Bonati , Massimo D'Elia

These lectures discuss the $\theta$ parameter of QCD. After an introduction to anomalies in four and two dimensions, the parameter is introduced. That such topological parameters can have physical effects is illustrated with two dimensional…

High Energy Physics - Phenomenology · Physics 2007-05-23 Michael Dine

We discuss our study of QCD in the presence of CP-odd electromagnetic (e.m.) background fields. We investigate the propagation of the CP-odd term from the e.m. sector to the strong sector, inducing an effective $\theta$ term. We discuss the…

High Energy Physics - Lattice · Physics 2013-12-11 Claudio Bonati , Guido Cossu , Massimo D'Elia , Marco Mariti , Francesco Negro

A new approach to perform numerical simulations of systems with a theta-vacuum term is proposed, tested, and applied to CP3 The main new ingredient of this approach is the method used to compute the probability distribution function of the…

High Energy Physics - Lattice · Physics 2015-06-25 Vicente Azcoiti , Giuseppe Di Carlo , Angelo Galante , Victor Laliena

We calculate the neutron electric dipole form factor induced by the CP violating theta-term of QCD, within a perturbative chiral quark model which includes pion and kaon clouds. On this basis we derive the neutron electric dipole moment and…

High Energy Physics - Phenomenology · Physics 2015-06-25 J. Kuckei , Claudio Dib , Amand Faessler , Th. Gutsche , Sergey Kovalenko , V. E. Lyubovitskij , K. Pumsa-ard

We present an update on our calculations of the matrix elements of the CP violating quark and gluon chromo-EDM operators, as well as the operators these mix with, such as the QCD Theta-term. Their contribution to the neutron EDM is obtained…

High Energy Physics - Lattice · Physics 2018-12-18 Tanmoy Bhattacharya , Boram Yoon , Rajan Gupta , Vincenzo Cirigliano

Effective field theory arguments suggest that if BSM sectors contain new sources of CP-violation that couple to QCD, these sources will renormalize the $\theta$ term and frustrate ultraviolet solutions to the strong CP problem.…

High Energy Physics - Phenomenology · Physics 2021-10-04 Jordy de Vries , Patrick Draper , Kaori Fuyuto , Jonathan Kozaczuk , Benjamin Lillard

We have calculated the neutron electric dipole moment (NEDM) in the presence of the CP violating $\theta$ term in lattice QCD with 2-flavor dynamical clover quarks, using the external electric field method. Accumulating a large number of…

High Energy Physics - Lattice · Physics 2008-12-18 E. Shintani , S. Aoki , Y. Kuramashi

Recent experiments and simulations have shown that two-dimensional systems can form tetratic phases with four-fold rotational symmetry, even if they are composed of particles with only two-fold symmetry. To understand this effect, we…

Soft Condensed Matter · Physics 2009-11-10 Jun Geng , Jonathan V. Selinger

We reanalyze in the first part of this paper the old question of P and CT realization in QCD. The second part is devoted to establish general results on the phase structure of this model in the presence of a $\theta$-vacuum term.

High Energy Physics - Lattice · Physics 2017-08-23 V. Azcoiti , A. Galante , V. Laliena

We present preliminary results for nucleon dipole moments computed with domain wall fermions. Our main target is the electric dipole moment of the neutron arising from the theta term in the gauge part of the QCD lagrangian. The calculated…

High Energy Physics - Lattice · Physics 2009-11-10 F. Berruto , T. Blum , K. Orginos , A. Soni

We compute the electric dipole moment d_n of the neutron from a fully dynamical simulation of lattice QCD with 2+1 flavors of clover fermions and nonvanishing theta term. The latter is rotated into the pseudoscalar density in the fermionic…

High Energy Physics - Lattice · Physics 2015-08-12 F. -K. Guo , R. Horsley , U. -G. Meissner , Y. Nakamura , H. Perlt , P. E. L. Rakow , G. Schierholz , A. Schiller , J. M. Zanotti

In the QCD vacuum, the nucleon form factors receive contributions from the underlying ensemble of topological pseudoparticles, which are sensitive to a finite vacuum angle $\theta$. We use this observation to derive a novel relationship…

High Energy Physics - Phenomenology · Physics 2025-11-11 Wei-Yang Liu , Ismail Zahed

We apply to the $CP^9$ model two recently proposed numerical techniques for simulation of systems with a theta term. The algorithms, successfully tested in the strong coupling limit, are applied to the weak coupling region. The results…

High Energy Physics - Lattice · Physics 2009-11-10 V. Azcoiti , G. Di Carlo , A. Galante , V. Laliena

Electric dipole moments (EDMs) of nucleons and nuclei, which are sought as evidence of CP violation, require lattice calculations to connect constraints from experiments to limits on the strong CP violation within QCD or CP violation…

High Energy Physics - Lattice · Physics 2019-01-18 S. Syritsyn , T. Izubuchi , H. Ohki

We present a complete analysis of the electric dipole moment (EDM) of the \rho-meson induced by CP violating operators of dimension 4 and 5 within the QCD sum rules approach. The set of CP-odd operators includes the theta term and the…

High Energy Physics - Phenomenology · Physics 2009-10-31 Maxim Pospelov , Adam Ritz

We present a calculation of the contribution of the $\Theta$-term to the neutron and proton electric dipole moments using seven 2+1+1-flavor HISQ ensembles. We also estimate the topological susceptibility for the 2+1+1 theory to be $\chi_Q…

High Energy Physics - Lattice · Physics 2021-06-16 Tanmoy Bhattacharya , Vincenzo Cirigliano , Rajan Gupta , Emanuele Mereghetti , Boram Yoon