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Related papers: Pion Weak Decay in a Magnetic Field

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Two-photon decays probe the structure of mesons and represent an important contribution to hadronic light-by-light scattering. For the neutral pion, the decay amplitude tests the effects of the chiral anomaly; for a heavy quarkonium state,…

High Energy Physics - Lattice · Physics 2015-06-15 Harvey B. Meyer

In this work, dispersion relations of $\pi^0$ and $\pi^{\pm}$ have been studied in vacuum in the limit of weak external magnetic field using a phenomenological pion-nucleon $(\pi N)$ Lagrangian. For our purpose, we have calculated the…

Nuclear Theory · Physics 2016-05-04 Souvik Priyam Adhya , Mahatsab Mandal , Subhrajyoti Biswas , Pradip K. Roy

We have developed a field theory formalism to calculate $in$-$medium$ properties of hadrons within a unified approach that exploits a single Lagrangian to describe simultaneously both matter background and meson fluctuations. In this paper…

High Energy Physics - Phenomenology · Physics 2008-11-26 Hee-Jung Lee , Byung-Yoon Park , Mannque Rho , Vicente Vento

The two photon decay width of the neutral pion is analyzed within the combined framework of Chiral Perturbation Theory and the 1/Nc expansion up to order p^6 and p^4 times 1/Nc in the decay amplitude. The eta' is explicitly included in the…

High Energy Physics - Phenomenology · Physics 2014-11-17 J. L. Goity , A. M. Bernstein , B. R. Holstein

The physics of pions within a finite volume is explored using lattice regularized chiral perturbation theory. This regularization scheme permits a straightforward computational approach to be used in place of analytical continuum…

High Energy Physics - Lattice · Physics 2009-11-10 B. Borasoy , R. Lewis

The relevance of the pion mass, provenient from a term which explicitely breaks chiral symmetry in the Lagrangian, for nucleon magnetic moment in the frame of the Skyrmion model in two different versions: the usual Skyrme model and a…

High Energy Physics - Lattice · Physics 2007-05-23 Fabio L. Braghin

The presence of axions introduces new diagrams at one-loop order to the two-photon decays of the neutral pion through axion-pion mixing. In this work, we calculate this correction, missing in all current calculations, in the framework of…

High Energy Physics - Phenomenology · Physics 2025-03-17 Zhen-Yan Lu , Yang Huang , Ji-Gui Cheng , Qi Lu , Shu-Peng Wang

We present simulation results for lattice QCD with light pions. For the quark fields we apply chirally symmetric lattice Dirac operators, in particular the overlap hypercube operator, along with the standard overlap operator for comparison.…

High Energy Physics - Lattice · Physics 2007-05-23 W. Bietenholz , S. Shcheredin

The introduction of axions gives rise to additional one-loop diagrams for the two-photon decays of neutral pions via axion-pion mixing. We compute this correction that has been overlooked in existing calculations, within the framework of…

High Energy Physics - Phenomenology · Physics 2025-07-25 Zhen-Yan Lu , Shu-Peng Wang , Qi Lu

The pion masses and the pion decay constant are calculated to 1-loop order in twisted mass Wilson chiral perturbation theory, assuming a large pion mass splitting and tuning to maximal twist. Taking the large mass splitting at leading order…

High Energy Physics - Lattice · Physics 2010-12-13 Oliver Bar

The dimensionless parameter $\xi' = M^2/(16 \pi^2 F^2)$, where $F$ is the pion decay constant in the chiral limit and $M$ is the pion mass at leading order in the quark mass, is expected to control the convergence of chiral perturbation…

High Energy Physics - Lattice · Physics 2009-02-11 D. J. Cecile , Shailesh Chandrasekharan

In this talk, we report our recent work on the pion weak decay constant (F_pi) and pion mass (m_pi) using the nonlocal chiral quark model with the finite quark-number chemical potential (mu) taken into account. Considering the breakdown of…

High Energy Physics - Phenomenology · Physics 2009-12-04 Seung-il Nam , Hyun-Chul Kim

We review two manifestations of chiral symmetry breaking in the pion sector. First, we examine the $\pi\pi$ scattering amplitude at threshold, which is completely determined by the chiral symmetry breaking part of the strong interaction,…

High Energy Physics - Phenomenology · Physics 2007-05-23 Dinko Pocanic

We present a lattice QCD study of the chiral properties of $(2\!+\!1)$-flavor QCD in background magnetic fields at zero temperature with physical pion masses. Simulations are performed using the highly improved staggered quark action across…

High Energy Physics - Lattice · Physics 2026-05-21 Heng-Tong Ding , Dan Zhang

We explore the chiral aspects of extrapolation of observables calculated within lattice QCD, using the nucleon magnetic moments as an example. Our analysis shows that the biggest effects of chiral dynamics occur for quark masses…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. W. Thomas , D. B. Leinweber , D. H. Lu

Recent attempts to determine the pion polarizability by dispersion relations yield values that disagree with the predictions of chiral perturbation theory. These dispersion relations are based on specific forms for the absorptive part of…

High Energy Physics - Phenomenology · Physics 2014-11-20 B. Pasquini , D. Drechsel , S. Scherer

Pionic beta decay \pi^+ to \pi^0 e^+ \nu_e is analyzed in chiral perturbation theory with virtual photons and leptons. All electromagnetic corrections up to order e^2 p^2 are taken into account. Theoretical results are confronted with…

High Energy Physics - Phenomenology · Physics 2010-11-23 Hannes Pichl

We investigate the real-time dynamics of the chiral magnetic effect in quantum electrodynamics (QED) and quantum chromodynamics (QCD). We consider a field configuration of parallel (chromo)electric and (chromo)magnetic fields with a weak…

High Energy Physics - Theory · Physics 2015-03-20 Harmen J. Warringa

Hyperon non-leptonic weak decay amplitudes are studied in the chiral perturbation theory. We employ the low energy effective weak Hamiltonian which contains the perturbative QCD correction. To include the non-perturbative QCD effect, quark…

High Energy Physics - Phenomenology · Physics 2007-05-23 K. Takayama , M. Oka

We investigate the modification of the pion self-energy at finite temperature due to its interaction with a low-density, isospin-symmetric nuclear medium embedded in a constant magnetic background. To one loop, for fixed temperature and…

Nuclear Theory · Physics 2013-12-10 Giuseppe Colucci , Eduardo S. Fraga , Armen Sedrakian