DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Kaon Photoproduction and the Λ Decay Parameter α

Abstract

The weak decay parameter $$\alpha_-$$ of the $$\Lambda$$ is an important quantity for the extraction of polarization observables in various experiments. Moreover, in combination with $$\alpha_+$$ from $$\bar\Lambda$$ decay it provides a measure for matter-antimatter asymmetry. The weak decay parameter also affects the decay parameters of the $$\Xi$$ and $$\Omega$$ baryons and, in general, any quantity in which the polarization of the $$\Lambda$$ is relevant. The recently reported value by the BESIII collaboration of $0.750(9)(4)$ is significantly larger than the previous PDG value of $0.642(13)$ that had been accepted and used for over 40 years. In this work we make an independent estimate of $$\alpha_-$$, using an extensive set of polarization data measured in kaon photoproduction in the baryon resonance region and constraints set by spin algebra. The obtained value is 0.721(6)(5). The result is corroborated by multiple statistical tests as well as a modern phenomenological model, showing that our new value yields the best description of the data in question. Furthermore, our analysis supports the new BESIII finding that $$\alpha_-$$ is significantly larger than the previous PDG value. Any experimental quantity relying on the value of $$\alpha_-$$ should therefore be re-considered.

Authors:
ORCiD logo [1];  [2];  [1];  [3];  [4];  [1];  [5]
  1. Univ. of Glasgow, Glasgow (United Kingdom)
  2. The George Washington Univ., Washington, D.C. (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
  3. Forschungszentrum Jülich, Julich (Germany)
  4. The George Washington Univ., Washington, D.C. (United States)
  5. Univ. Bonn, Bonn (Germany)
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP)
OSTI Identifier:
1572152
Report Number(s):
JLAB-THY-19-3019; DOE/OR/23177-4767; arXiv:1904.07616
Journal ID: ISSN 0031-9007; PRLTAO; TRN: US2100205
Grant/Contract Number:  
ST/P004458/1; PHY-1452055; AC05-06OR23177; SC0016582; TRR110; 11621131001; EP/M01326X/1; EP/R018634/1
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 123; Journal Issue: 18; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Ireland, David G., Döring, M., Glazier, Derek I., Haidenbauer, J., Mai, M., Murray-Smith, Roderick, and Rönchen, D. Kaon Photoproduction and the Λ Decay Parameter α–. United States: N. p., 2019. Web. doi:10.1103/PhysRevLett.123.182301.
Ireland, David G., Döring, M., Glazier, Derek I., Haidenbauer, J., Mai, M., Murray-Smith, Roderick, & Rönchen, D. Kaon Photoproduction and the Λ Decay Parameter α–. United States. https://doi.org/10.1103/PhysRevLett.123.182301
Ireland, David G., Döring, M., Glazier, Derek I., Haidenbauer, J., Mai, M., Murray-Smith, Roderick, and Rönchen, D. Mon . "Kaon Photoproduction and the Λ Decay Parameter α–". United States. https://doi.org/10.1103/PhysRevLett.123.182301. https://www.osti.gov/servlets/purl/1572152.
@article{osti_1572152,
title = {Kaon Photoproduction and the Λ Decay Parameter α–},
author = {Ireland, David G. and Döring, M. and Glazier, Derek I. and Haidenbauer, J. and Mai, M. and Murray-Smith, Roderick and Rönchen, D.},
abstractNote = {The weak decay parameter $\alpha_-$ of the $\Lambda$ is an important quantity for the extraction of polarization observables in various experiments. Moreover, in combination with $\alpha_+$ from $\bar\Lambda$ decay it provides a measure for matter-antimatter asymmetry. The weak decay parameter also affects the decay parameters of the $\Xi$ and $\Omega$ baryons and, in general, any quantity in which the polarization of the $\Lambda$ is relevant. The recently reported value by the BESIII collaboration of $0.750(9)(4)$ is significantly larger than the previous PDG value of $0.642(13)$ that had been accepted and used for over 40 years. In this work we make an independent estimate of $\alpha_-$, using an extensive set of polarization data measured in kaon photoproduction in the baryon resonance region and constraints set by spin algebra. The obtained value is 0.721(6)(5). The result is corroborated by multiple statistical tests as well as a modern phenomenological model, showing that our new value yields the best description of the data in question. Furthermore, our analysis supports the new BESIII finding that $\alpha_-$ is significantly larger than the previous PDG value. Any experimental quantity relying on the value of $\alpha_-$ should therefore be re-considered.},
doi = {10.1103/PhysRevLett.123.182301},
journal = {Physical Review Letters},
number = 18,
volume = 123,
place = {United States},
year = {Mon Oct 28 00:00:00 EDT 2019},
month = {Mon Oct 28 00:00:00 EDT 2019}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 25 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Partial-wave analysis of γ p K + Λ using a multichannel framework
journal, May 2019


JURECA: Modular supercomputer at Jülich Supercomputing Centre
journal, January 2018

  • Krause, Dorian; Thörnig, Philipp
  • Journal of large-scale research facilities JLSRF, Vol. 4
  • DOI: 10.17815/jlsrf-4-121-1

Strong Evidence for Nucleon Resonances near 1900 MeV
journal, August 2017


The impact of $K^{+}\Lambda$ K + Λ photoproduction on the resonance spectrum
journal, June 2018


Coupled-channel analysis of K Σ production on the nucleon up to 2.0 GeV
journal, November 2013


Antinucleon–nucleon interaction at low energy: scattering and protonium
journal, September 2002


Isospin decomposition of γ N N * transitions within a dynamical coupled-channels model
journal, July 2016


Erratum to: Photocouplings at the pole from pion photoproduction
journal, May 2015


Production and Decay of Cascade Hyperons
journal, March 1969

  • Dauber, Philip M.; Berge, J. Peter; Hubbard, J. Richard
  • Physical Review, Vol. 179, Issue 5
  • DOI: 10.1103/PhysRev.179.1262

Completeness rules for spin observables in pseudoscalar meson photoproduction
journal, April 1997


First measurement of Ξ− polarization in photoproduction
journal, August 2018


Violation of CP in variance, C asymmetry, and baryon asymmetry of the universe
journal, May 1991


Bayesian Inference of the Resonance Content of p ( γ , K + ) Λ
journal, May 2012


Photocouplings at the pole from pion photoproduction
journal, June 2014


First measurement of beam-recoil observables C x and C z in hyperon photoproduction
journal, March 2007


Differential cross section and recoil polarization measurements for the γ p K + Λ reaction using CLAS at Jefferson Lab
journal, February 2010


Measurement of matter–antimatter differences in beauty baryon decays
journal, January 2017

  • LHCb Collaboration,
  • Nature Physics, Vol. 13, Issue 4, p. 391-396
  • DOI: 10.1038/nphys4021

Photoproduction of Λ and Σ 0 hyperons using linearly polarized photons
journal, June 2016


On the validity of chiral perturbation theory for weak hyperon decays
journal, January 1985


Partial-Wave Analysis of K p Ξ K + at 2   GeV c
journal, June 1967


Global Λ hyperon polarization in nuclear collisions
journal, August 2017


emcee : The MCMC Hammer
journal, March 2013

  • Foreman-Mackey, Daniel; Hogg, David W.; Lang, Dustin
  • Publications of the Astronomical Society of the Pacific, Vol. 125, Issue 925
  • DOI: 10.1086/670067

Eta photoproduction in a combined analysis of pion- and photon-induced reactions
journal, June 2015


A measurement of the β-parameter in the charged nonleptonic decay of the Λ0 hyperon
journal, January 1972


Polarization and entanglement in baryon–antibaryon pair production in electron–positron annihilation
journal, May 2019


Review of Particle Physics
journal, August 2018


Gaussian Processes for Machine Learning
book, January 2005


Fitting parton distribution data with multiplicative normalization uncertainties
journal, May 2010

  • Ball, Richard D.; Del Debbio, Luigi; Forte, Stefano
  • Journal of High Energy Physics, Vol. 2010, Issue 5
  • DOI: 10.1007/JHEP05(2010)075

Electromagnetic production of kaons from protons, and baryon electromagnetic form factors
journal, March 2012


Weak and Electromagnetic Interactions of Hyperons: a Chiral Approach
journal, October 2000


Determining pseudoscalar meson photoproduction amplitudes from complete experiments
journal, April 2011

  • Sandorfi, A. M.; Hoblit, S.; Kamano, H.
  • Journal of Physics G: Nuclear and Particle Physics, Vol. 38, Issue 5
  • DOI: 10.1088/0954-3899/38/5/053001

On the use of the covariance matrix to fit correlated data
journal, July 1994

  • D'Agostini, G.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 346, Issue 1-2
  • DOI: 10.1016/0168-9002(94)90719-6

First Measurement of Transferred Polarization in the Exclusive e p e K + Λ Reaction
journal, April 2003


Final state interactions in nonleptonic hyperon decays
journal, June 2003


Coupled-channel dynamics in the reactions πN → πN, ηN, KΛ, KΣ
journal, April 2013


Review of Particle Physics
text, January 2008


Bayesian inference of the resonance content of p ( γ , K + ) Λ
journal, January 2012


Review of Particle Physics
text, January 2018


Measurement of the transverse polarization of Λ and Λ ¯ hyperons produced in proton-proton collisions at √s=7 TeV using the ATLAS detector
text, January 2015

  • Atlas, Collaboration; Agustoni, Marco; Beck, Hans Peter
  • American Physical Society
  • DOI: 10.7892/boris.87673

Review of Particle Physics
text, January 2012

  • Beringer, J.; Arguin, J.; Barnett, R.
  • Deutsches Elektronen-Synchrotron, DESY, Hamburg
  • DOI: 10.3204/phppubdb-24149

Measurement of matter-antimatter differences in beauty baryon decays
text, January 2017


Photocouplings at the Pole from Pion Photoproduction
text, January 2014


Eta photoproduction in a combined analysis of pion- and photon-induced reactions
text, January 2015


Strong evidence for nucleon resonances near 1900\,MeV
text, January 2017


Final state interactions in nonleptonic hyperon decays
text, January 2003