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Spin alignment of vector mesons in heavy ion and proton - proton collisions

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 نشر من قبل Alejandro Ayala
 تاريخ النشر 2009
  مجال البحث
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 تأليف Alejandro Ayala




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The spin alignment matrix element rho_{00} for the vector mesons K^{*0} and phi(1020) has been measured in RHIC at central rapidities. These measurements are consistent with the absence of polarization with respect to the reaction plane in mid-central Au + Au collisions whereas, when measured with respect to the production plane in the same reactions and in p + p collisions, a non-vanishing and p_perp-dependent rho_{00} is found. We show that this behavior can be understood in a simple model of vector meson production where the spin of their constituent quarks is oriented during hadronization as the result of Thomas precession.



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