scholarly journals N-to-ΔElectromagnetic-Transition Form Factors from Lattice QCD

2005 ◽  
Vol 94 (2) ◽  
Author(s):  
C. Alexandrou ◽  
Ph. de Forcrand ◽  
H. Neff ◽  
J. W. Negele ◽  
W. Schroers ◽  
...  
2020 ◽  
Vol 80 (11) ◽  
Author(s):  
June-Young Kim ◽  
Hyun-Chul Kim

AbstractWe investigate the electromagnetic transition form factors of the baryon decuplet to the baryon octet, based on the self-consistent SU(3) chiral quark-soliton model, taking into account the effects of explicit breaking of flavor SU(3) symmetry. We emphasize the $$Q^2$$ Q 2 dependence of the electromagnetic $$N\rightarrow \Delta $$ N → Δ transition form factors and the ratios of E2/M1 and C2/M1 in comparison with the experimental and empirical data. In order to compare the present results of the electromagnetic transition form factors of the $$N\rightarrow \Delta $$ N → Δ with those from lattice QCD, we evaluate the form factors with the pion mass deviated from its physical value. The results of the E2/M1 and C2/M1 ratios are in good agreement with the lattice data. We also present the results of the electromagnetic transition form factors for the decuplet to the octet transitions.


2008 ◽  
Vol 77 (8) ◽  
Author(s):  
C. Alexandrou ◽  
G. Koutsou ◽  
H. Neff ◽  
J. W. Negele ◽  
W. Schroers ◽  
...  

2004 ◽  
Vol 69 (11) ◽  
Author(s):  
C. Alexandrou ◽  
Ph. de Forcrand ◽  
Th. Lippert ◽  
H. Neff ◽  
J.W. Negele ◽  
...  

2006 ◽  
Vol 21 (04) ◽  
pp. 720-725 ◽  
Author(s):  
◽  
J. W. Negele ◽  
B. Bistrovic ◽  
R. G. Edwards ◽  
G. Fleming ◽  
...  

The structure of neutrons, protons, and other strongly interacting particles is now being calculated in full, unquenched lattice QCD with quark masses entering the chiral regime. This talk describes selected examples, including the nucleon axial charge, structure functions, electromagnetic form factors, the origin of the nucleon spin, the transverse structure of the nucleon, and the nucleon to Delta transition form factor.


2021 ◽  
Vol 36 (23) ◽  
pp. 2130013
Author(s):  
K. U. Can

Composite nature of a particle can be probed by electromagnetic interactions and information about their structure is embedded in form factors. Most of the experimental and theoretical efforts on baryon electromagnetic form factors have been focused on nucleon while the data on charmed sector are limited to spectroscopy, and weak and strong decays. Forthcoming experiments with a heavy-hadron physics program at major experimental facilities are expected to provide a wealth of information on charmed baryons, which calls for a better understanding of the heavy-sector dynamics from theoretical grounds. We review the progress in calculating the elastic and transition form factors of charmed baryons in lattice QCD. A collection of static observables, e.g. charge radii, multipole moments, are presented along with the elastic form factors up to [Formula: see text]. As one would expect the charmed baryons are compact in comparison to nucleon and this is due to the presence of valence charm quark(s). The elastic and transition magnetic moments are both suppressed. The lattice results provide predictions for the transition magnetic moments, transition and helicity amplitudes and consequentially the decay widths of some singly and doubly charmed baryons. In general, lattice results are consonant with the qualitative expectations of quark model and heavy-quark symmetry, although there are apparent quantitative differences up to two orders of magnitude in some cases. There are, however, indications that the lattice results can be utilized to improve the model predictions. Nevertheless, discrepancies between the lattice and nonlattice calculations need to be understood better to have a solid insight into the dynamics of the heavy sector. Furthermore, reliably determined charmed baryon observables would be invaluable input to investigate the nature of exotic states, which further emphasizes the importance of rigorous, first-principles calculations to advance our understanding of the dynamics of the heavy quarks and strong interactions.


2018 ◽  
Vol 175 ◽  
pp. 01016 ◽  
Author(s):  
Raúl A. Briceño

The spectrum of hadron is mainly composed as shortly-lived states (resonance) that decay onto two or more hadrons. These resonances play an important role in a variety of phenomenologically significant processes. In this talk, I give an overview on the present status of a rigorous program for studying of resonances and their properties using lattice QCD. I explain the formalism needed for extracting resonant amplitudes from the finite-volume spectra. From these one can extract the masses and widths of resonances. I present some recent examples that illustrate the power of these ideas. I then explain similar formalism that allows for the determination of resonant electroweak amplitudes from finite-volume matrix elements. I use the recent calculation of the πγ* → ππ amplitude as an example illustrating the power of this formalism. From such amplitudes one can determine transition form factors of resonances. I close by reviewing on-going efforts to generalize these ideas to increasingly complex reactions and I then give a outlook of the field.


2007 ◽  
Vol 98 (5) ◽  
Author(s):  
C. Alexandrou ◽  
Th. Leontiou ◽  
J. W. Negele ◽  
A. Tsapalis

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Ulrich Haisch ◽  
Amando Hala

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.


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