$\chi_{c1}$ and $\chi_{c2}$ polarization as a probe of color octet channel

We analyze joint LHC data on the production of $\chi _{c1}$ and $\chi _{c2}$ mesons together with the polarization data obtained very recently by the CMS Collaboration at $\sqrt{s} = 8$ TeV. Our consideration is based on the $k_T$-factorization approach and nonrelativistic QCD formalism for the form...

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Detalles Bibliográficos
Autores principales: Baranov, S.P., Lipatov, A.V.
Lenguaje:eng
Publicado: 2020
Materias:
hep-ph
Particle Physics - Phenomenology
Acceso en línea:https://dx.doi.org/10.1140/epjc/s10052-020-08617-0
http://cds.cern.ch/record/2717114
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author Baranov, S.P.
Lipatov, A.V.
author_facet Baranov, S.P.
Lipatov, A.V.
author_sort Baranov, S.P.
collection CERN
description We analyze joint LHC data on the production of $\chi _{c1}$ and $\chi _{c2}$ mesons together with the polarization data obtained very recently by the CMS Collaboration at $\sqrt{s} = 8$ TeV. Our consideration is based on the $k_T$-factorization approach and nonrelativistic QCD formalism for the formation of bound states. The observed polar anisotropy of $\chi _{c1}$ and $\chi _{c2}$ decays can be described as a combined effect of the color-singlet and color-octet contributions. We extract the corresponding long-distance matrix elements from the fits. Our fits point to unequal color singlet wave functions for $\chi _{c1}$ and $\chi _{c2}$ states.
id cern-2717114
institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2020
record_format invenio
spelling cern-27171142021-11-12T07:29:44Zdoi:10.1140/epjc/s10052-020-08617-0http://cds.cern.ch/record/2717114engBaranov, S.P.Lipatov, A.V.$\chi_{c1}$ and $\chi_{c2}$ polarization as a probe of color octet channelhep-phParticle Physics - PhenomenologyWe analyze joint LHC data on the production of $\chi _{c1}$ and $\chi _{c2}$ mesons together with the polarization data obtained very recently by the CMS Collaboration at $\sqrt{s} = 8$ TeV. Our consideration is based on the $k_T$-factorization approach and nonrelativistic QCD formalism for the formation of bound states. The observed polar anisotropy of $\chi _{c1}$ and $\chi _{c2}$ decays can be described as a combined effect of the color-singlet and color-octet contributions. We extract the corresponding long-distance matrix elements from the fits. Our fits point to unequal color singlet wave functions for $\chi _{c1}$ and $\chi _{c2}$ states.We analyze the first LHC data on $\chi_{c1}$ and $\chi_{c2}$ polarization obtained very recently by the CMS Collaboration at $\sqrt s = 8$~TeV. We describe the perturbative production of $c\bar c$ pair with $k_T$-factorization approach and use nonrelativistic QCD formalism for the formation of bound states. We demonstrate that the polar anisotropy of $\chi_{c1}$ and $\chi_{c2}$ mesons is strongly sensitive to the color octet contributions. We extract the long-distance matrix elements for $\chi_{c1}$ and $\chi_{c2}$ mesons from the first CMS polarization measurement %on the polarization parameters $\lambda_{\theta}^{\chi_{c1}}$ and $\lambda_{\theta}^{\chi_{c2}}$ obtained at $\sqrt s = 8$~TeV together with available LHC data on the $\chi_{c1}$ and $\chi_{c2}$ transverse momentum distributions (and their ratios) collected at $\sqrt s = 7$~TeV. Our fit points to unequal color singlet wave functions of $\chi_{c1}$ and $\chi_{c2}$ states.arXiv:2004.03220oai:cds.cern.ch:27171142020-04-07
spellingShingle hep-ph
Particle Physics - Phenomenology
Baranov, S.P.
Lipatov, A.V.
$\chi_{c1}$ and $\chi_{c2}$ polarization as a probe of color octet channel
title $\chi_{c1}$ and $\chi_{c2}$ polarization as a probe of color octet channel
title_full $\chi_{c1}$ and $\chi_{c2}$ polarization as a probe of color octet channel
title_fullStr $\chi_{c1}$ and $\chi_{c2}$ polarization as a probe of color octet channel
title_full_unstemmed $\chi_{c1}$ and $\chi_{c2}$ polarization as a probe of color octet channel
title_short $\chi_{c1}$ and $\chi_{c2}$ polarization as a probe of color octet channel
title_sort $\chi_{c1}$ and $\chi_{c2}$ polarization as a probe of color octet channel
topic hep-ph
Particle Physics - Phenomenology
url https://dx.doi.org/10.1140/epjc/s10052-020-08617-0
http://cds.cern.ch/record/2717114
work_keys_str_mv AT baranovsp chic1andchic2polarizationasaprobeofcoloroctetchannel
AT lipatovav chic1andchic2polarizationasaprobeofcoloroctetchannel

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