Contribution to a conference proceedings/Internal Report

PUBDB-2015-05833

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Helicity Amplitudes and Angular Decay Distributions

Körner, J. G. (Corresponding author)

2014
Deutsches Elektronen-Synchrotron, DESY Hamburg

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Please use a persistent id in citations: doi:10.3204/DESY-PROC-2013-03/Koerner

Report No.: MITP-14-004; arXiv:1402.2787

Abstract: I discuss how to obtain angular decay distributions for sequentialcascade decays using helicity methods. The angular decay distributionsfollow from a reasonably simple master formula involving bilinearforms of helicity amplitudes and Wigner's $d$ functions. I discussin some detail the issue of gauge invariance for off-shell gauge bosons.As a technical exercise I calculate the linear relation between thehelicity amplitudes and the invariant amplitudes of semileptonic andrare baryon decays. I discuss two explicit examples of angular decaydistributions for (i) the decay $t\to b+W^+(\to \ell^+\nu_\ell)$ (whichleads to the notion of the helicity fractions of the $W^+$), and (ii)the sequential decay $\Lambda_b\to\Lambda(\to p\pi^-)+J/\psi(\to \ell^+\ell^-)$.T = Helicity Amplitudes and Angular Decay Distributions

Keyword(s): helicity: amplitude analysis ; baryon: decay ; gauge boson: off-shell ; invariance: gauge ; cascade decay

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Contributing Institute(s):

1. Bibliothek und Dokumentation (L)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

Experiment(s):

1. Facility (machine) HERA

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Linked articles:

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Proceedings/Internal Report Ali, A. (Editor)DESY* ; Bystritskiy, Y. (Editor) ; Ivanov, M. (Editor)
Proceedings, Helmholtz International School on Physics of Heavy Quarks and Hadrons (HQ2013)
2014Helmholtz International School on Physics of Heavy Quarks and Hadrons , HQ2013, DubnaDubna, Russia, 15 Jul 2013 - 28 Jul 20132013-07-152013-07-28 Hamburg : Deutsches Elektronen-Synchrotron, DESY (2014) [10.3204/DESY-PROC-2013-03]2014     Files BibTeX | EndNote: XML, Text | RIS

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