Hadron spin and external fields

The interactions of hadron spin with gravity and electromagnetic field and their implication for hadron spin structure are considered. The extension of equivalence principle naturally leads to the closeness of vector meson magnetic moment to that of electroweak boson. This similarity is confirmed in the lattice QCD. The effective gravity in AdS/QCD allows to connect the [Formula: see text]-dependence of GPDs (and therefore electromagnetic and gravitational form factors) with [Formula: see text]-dependemce of TMDs. The possible cosmological implications of equivalence principle extension are discussed.

Download Full-text

Pseudoscalar and vector meson form factors from lattice QCD

Physical Review D ◽

10.1103/physrevd.75.094504 ◽

2007 ◽

Vol 75 (9) ◽

Cited By ~ 57

Author(s):

J. N. Hedditch ◽

W. Kamleh ◽

B. G. Lasscock ◽

D. B. Leinweber ◽

A. G. Williams ◽

...

Keyword(s):

Vector Meson ◽

Lattice Qcd ◽

Form Factors

Download Full-text

Nucleon Electromagnetic Structure from Lattice QCD

HNPS Proceedings ◽

10.12681/hnps.2617 ◽

2020 ◽

Vol 15 ◽

pp. 31

Author(s):

C. Alexandrou ◽

G. Koutsou ◽

H. Neff ◽

J. W. Negele ◽

W. Schroers ◽

...

Keyword(s):

Lattice Qcd ◽

Momentum Transfer ◽

Magnetic Moment ◽

Qualitative Agreement ◽

Pion Mass ◽

Form Factors ◽

Effective Theory ◽

Electromagnetic Form Factors ◽

Electromagnetic Structure ◽

Nucleon Magnetic Moment

We present an evaluation of nucleon to Δ electromagnetic form factors within Lattice QCD. The EMR and CMR ratios are calculated both in the quenched theory and using two degenerate flavors of dynamical Wilson fermions. We obtain values in qualitative agreement to experiment. In addition, we evaluate the isovector Sachs electromagnetic form factors of the nucleon both in the quenched and unquenched theory for momentum transfer squared in the range between 0.1 and 2 GeV2. The nucleon magnetic moment and r.m.s. radii are obtained using chiral effective theory to extrapolate to the physical pion mass.

Download Full-text

The Electromagnetic Interactions

10.1093/oso/9780192844200.003.0016 ◽

2021 ◽

pp. 329-334

Author(s):

J. Iliopoulos ◽

T.N. Tomaras

Keyword(s):

Electromagnetic Field ◽

Magnetic Moment ◽

Anomalous Magnetic Moment ◽

Quantum Electrodynamics ◽

Form Factors ◽

External Electromagnetic Field ◽

Explicit Calculation ◽

Loop Order ◽

Electromagnetic Interactions ◽

Infrared Divergences

We briefly review the birth of renormalisation theory at the 1947 Shelter Island conference. We study the particular case of quantum electrodynamics in the example of an electron scattered by an external electromagnetic field. We give the general form of the amplitude in terms of form factors. At one loop the amplitude has both ultraviolet and infrared divergences. We show how to absorb the ultraviolet divergences by means of counterterms whose values are determined by the renormalisation conditions. We also show that at one loop order the electron anomalous magnetic moment is free of divergences, ultraviolet as well as infrared, and present its explicit calculation.

Download Full-text

Light-cone sum rules for proton decay

Journal of High Energy Physics ◽

10.1007/jhep05(2021)258 ◽

2021 ◽

Vol 2021 (5) ◽

Author(s):

Ulrich Haisch ◽

Amando Hala

Keyword(s):

Lattice Qcd ◽

Light Cone ◽

Sum Rules ◽

State Of The Art ◽

Form Factors ◽

Baryon Number ◽

Proton Decay ◽

Matrix Elements ◽

Decay Channels ◽

Systematic Uncertainties

Abstract We estimate the form factors that parametrise the hadronic matrix elements of proton-to-pion transitions with the help of light-cone sum rules. These form factors are relevant for semi-leptonic proton decay channels induced by baryon-number violating dimension-six operators, as typically studied in the context of grand unified theories. We calculate the form factors in a kinematical regime where the momentum transfer from the proton to the pion is space-like and extrapolate our final results to the regime that is relevant for proton decay. In this way, we obtain estimates for the form factors that show agreement with the state-of-the-art calculations in lattice QCD, if systematic uncertainties are taken into account. Our work is a first step towards calculating more involved proton decay channels where lattice QCD results are not available at present.

Download Full-text