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Title: Strong one-pion decay of {sigma}c, {sigma}{sub c}{sup *} and {xi}{sub c}{sup *}

Abstract

Working in the framework of a nonrelativistic quark model we evaluate the widths for the strong one-pion decays {sigma}c {yields} {lambda}c {pi}, {sigma}{sub c}{sup *} {yields} {lambda}{sub c} {pi} and {xi}{sub c}{sup *} {yields} {xi}{sub c} {pi}. We take advantage of the constraints imposed by heavy quark symmetry to solve the three-body problem by means of a simple variational ansatz. We use partial conservation of the axial current hypothesis to get the strong vertices from weak axial current matrix elements. Our results are in good agreement with experimental data.

Authors:
;  [1]; ;  [2]
  1. Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada (Spain)
  2. Grupo de Fisica Nuclear, Departamento de Fisica Fundamental e IUFFyM, Facultad de Ciencias, E-37008 Salamanca (Spain)
Publication Date:
OSTI Identifier:
21056857
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 892; Journal Issue: 1; Conference: QCHS7: 7. conference on quark confinement and the hadron spectrum, Ponta Delgada, Acores (Portugal), 2-7 Sep 2006; Other Information: DOI: 10.1063/1.2714419; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; B QUARKS; C QUARKS; HADRONIC PARTICLE DECAY; LAMBDA C-2625 BARYONS; MATRIX ELEMENTS; PARTICLE PRODUCTION; PARTICLE WIDTHS; PIONS; QUARK MODEL; SIGMA BARYONS; SIGMA C-2455 BARYONS; SYMMETRY; T QUARKS; THREE-BODY PROBLEM; VARIATIONAL METHODS; XI C NEUTRAL BARYONS

Citation Formats

Albertus, C., Nieves, J., Hernandez, E., and Verde-Velasco, J. M. Strong one-pion decay of {sigma}c, {sigma}{sub c}{sup *} and {xi}{sub c}{sup *}. United States: N. p., 2007. Web. doi:10.1063/1.2714419.
Albertus, C., Nieves, J., Hernandez, E., & Verde-Velasco, J. M. Strong one-pion decay of {sigma}c, {sigma}{sub c}{sup *} and {xi}{sub c}{sup *}. United States. doi:10.1063/1.2714419.
Albertus, C., Nieves, J., Hernandez, E., and Verde-Velasco, J. M. Tue . "Strong one-pion decay of {sigma}c, {sigma}{sub c}{sup *} and {xi}{sub c}{sup *}". United States. doi:10.1063/1.2714419.
@article{osti_21056857,
title = {Strong one-pion decay of {sigma}c, {sigma}{sub c}{sup *} and {xi}{sub c}{sup *}},
author = {Albertus, C. and Nieves, J. and Hernandez, E. and Verde-Velasco, J. M.},
abstractNote = {Working in the framework of a nonrelativistic quark model we evaluate the widths for the strong one-pion decays {sigma}c {yields} {lambda}c {pi}, {sigma}{sub c}{sup *} {yields} {lambda}{sub c} {pi} and {xi}{sub c}{sup *} {yields} {xi}{sub c} {pi}. We take advantage of the constraints imposed by heavy quark symmetry to solve the three-body problem by means of a simple variational ansatz. We use partial conservation of the axial current hypothesis to get the strong vertices from weak axial current matrix elements. Our results are in good agreement with experimental data.},
doi = {10.1063/1.2714419},
journal = {AIP Conference Proceedings},
number = 1,
volume = 892,
place = {United States},
year = {Tue Feb 27 00:00:00 EST 2007},
month = {Tue Feb 27 00:00:00 EST 2007}
}
  • We present results for the strong widths corresponding to the {sigma}{sub c}{yields}{lambda}{sub c}{pi}, {sigma}{sub c}*{yields}{lambda}{sub c}{pi} and {xi}{sub c}*{yields}{xi}{sub c}{pi} decays. The calculations have been done in a nonrelativistic constituent quark model with wave functions that take advantage of the constraints imposed by heavy quark symmetry. Partial conservation of axial current hypothesis allows us to determine the strong vertices from an analysis of the axial current matrix elements. Our results {gamma}({sigma}{sub c}{sup ++}{yields}{lambda}{sub c}{sup +}{pi}{sup +})=2.41{+-}0.07{+-}0.02 MeV, {gamma}({sigma}{sub c}{sup +}{yields}{lambda}{sub c}{sup +}{pi}{sup 0})=2.79{+-}0.08{+-}0.02 MeV, {gamma}({sigma}{sub c}{sup 0}{yields}{lambda}{sub c}{sup +}{pi}{sup -})=2.37{+-}0.07{+-}0.02 MeV, {gamma}({sigma}{sub c}*{sup ++}{yields}{lambda}{sub c}{sup +}{pi}{sup +})=17.52{+-}0.74{+-}0.12 MeV, {gamma}({sigma}{sub c}*{supmore » +}{yields}{lambda}{sub c}{sup +}{pi}{sup 0})=17.31{+-}0.73{+-}0.12 MeV, {gamma}({sigma}{sub c}*{sup 0}{yields}{lambda}{sub c}{sup +}{pi}{sup -})=16.90{+-}0.71{+-}0.12 MeV, {gamma}({xi}{sub c}*{sup +}{yields}{xi}{sub c}{sup 0}{pi}{sup +}+{xi}{sub c}{sup +}{pi}{sup 0})=3.18{+-}0.10{+-}0.01 MeV, and {gamma}({xi}{sub c}*{sup 0}{yields}{xi}{sub c}{sup +}{pi}{sup -}+{xi}{sub c}{sup 0}{pi}{sup 0})=3.03{+-}0.10{+-}0.01 MeV are in good agreement with experimental determinations.« less
  • Using the CLEO II detector at the Cornell Electron Storage Ring we have observed the decay modes {Xi}{sup +}{sub {ital c}}{r_arrow}{Xi}{sup 0}{ital e}{sup +}{nu}{sub {ital e}} and {Xi}{sup 0}{sub {ital c}}{r_arrow}{Xi}{sup {minus}}{ital e}{sup +}{nu}{sub {ital e}} by the detection of a {Xi}-positron pair of appropriate invariant mass. We find {ital B} ({Xi}{sup +}{sub {ital c}}{r_arrow}{Xi}{sup 0}{ital e}{sup +}{nu}{sub {ital e}}){sigma}({ital e}{sup +}{ital e}{sup {minus}}{r_arrow} {Xi}{sup +}{sub {ital cX}})=1.55{plus_minus}0.33{plus_minus}0.25 pb, {ital B} ({Xi}{sup 0}{sub {ital c}}{r_arrow}{Xi}{sup {minus}}{ital e}{sup +}{nu}{sub {ital e}}){sigma}({ital e}{sup +}{ital e}{sup {minus}}{r_arrow} {Xi}{sup 0}{sub {ital cX}})=0.63{plus_minus}0.12{plus_minus}0.10 pb, {ital B} ({Xi}{sup +}{sub {ital c}}{r_arrow}{Xi}{sup {minus}}{pi}{sup +}{pi}{sup +})/ {ital B}more » ({Xi}{sup +}{sub {ital c}}{r_arrow}{Xi}{sup 0}{ital e}{sup +}{nu}{sub {ital e}})= 0.44{plus_minus}0.11{sub {minus}0.06}{sup +0.11}, and {ital B} ({Xi}{sup 0}{sub {ital c}}{r_arrow}{Xi}{sup {minus}}{pi}{sup +})/{ital B} ({Xi}{sup 0}{sub {ital c}}{r_arrow}{Xi}{sup {minus}}{ital e}{sup +}{nu}{sub {ital e}})= 0.32{plus_minus}0.10{sub {minus}0.03}{sup +0.05}. Assuming the {Xi}{sup +}{sub {ital c}} and {Xi}{sup 0}{sub {ital c}} are equally produced in {ital e}{sup +}{ital e}{sup {minus}} annihilation events at 10 GeV, the lifetime ratio of {Xi}{sup +}{sub {ital c}}/{Xi}{sup 0}{sub {ital c}} is measured to be 2.46{plus_minus}0.70{sub {minus}0.23}{sup +0.33}.« less
  • We report the measurement of new modes of the charmed baryon [Lambda][sub [ital c]][sup +] using data recorded by the CLEO II detector at the Cornell Electron Storage Ring. We find branching ratios, relative to [Lambda][sub [ital c]][sup +][r arrow][ital pK][sup [minus]][pi][sup +], of 0.070[plus minus]0.011[plus minus]0.011 for [Lambda][sub [ital c]][sup +][r arrow][Sigma][sup +][ital K+][ital K[minus]], 0.069[plus minus]0.023[plus minus]0.016 for [Lambda][sub [ital c]][sup +][r arrow][Sigma][phi], 0.078[plus minus]0.013[plus minus]0.013 for [Lambda][sub [ital c]][sup +][r arrow][Xi][sup 0][ital K+], and 0.053[plus minus]0.016[plus minus]0.010 for [Lambda][sub [ital c]][sup +][r arrow][Xi][sup *0][ital K+]. These measurements indicate that [ital W]-exchange diagrams contribute to [Lambda][sub [ital c]][supmore » +] decay. We have also made a new measurement of the previously found mode [Lambda][sub [ital c]][sup +][r arrow][Xi][sup [minus]][ital K+][pi][sup +].« less
  • In the Brookhaven National Laboratory 20.8-GeV/c negative-hyperon beam, we have measured the production ratios ..sigma../sup -//..pi../sup -/, ..xi../sup -//..pi../sup -/, and ..sigma../sup -//..xi../sup -/ by 29.4-GeV/c protons incident on A1 and A1/sub 2/O/sub 3/ targets. We have also measured the asymmetry parameter in the decay ..xi../sup -/ ..-->.. ..lambda pi../sup -/ and find ..cap alpha../sub ..xi../-=-0.49 +- 0.04.
  • The authors present evidence for the new decay modes {Xi}{sub c}{sup 0}{r_arrow}{Xi}{sup {minus}}{pi}{sup +}{pi}{sup 0}, {Xi}{sub c}{sup 0}{r_arrow}{Xi}{sup 0}{pi}{sup +}{pi}{sup {minus}}, {Xi}{sub c}{sup +}{r_arrow}{Xi}{sup 0}{pi}{sup +} and {Xi}{sub c}{sup +}{r_arrow}{Xi}{sup 0}{pi}{sup +}{pi}{sup 0} observed by the CLEO-II detector at CESR. The {Xi}{sup 0} has been reconstructed through the decay mode of {Xi}{sup 0}{r_arrow}{Lambda}{pi}{sup 0}, where {Lambda}{r_arrow} p {pi}{sup {minus}} and {pi}{sup 0}{r_arrow}{gamma}{gamma}, while the {Xi}{sup {minus}} has been reconstructed through the decay mode of {Xi}{sup {minus}}{r_arrow}{Lambda}{pi}{sup {minus}}.