Global Bayesian analysis of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mi mathvariant="normal">J</mml:mi> <mml:mo>/</mml:mo> <mml:mi>ψ</mml:mi> </mml:mrow> </mml:math> photoproduction on proton and lead targets
Heikki Mäntysaari, Hendrik Roch, Farid Salazar, Björn Schenke, Chun Shen, Wenbin Zhao
Abstract
We perform a global Bayesian analysis of diffractive <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi mathvariant="normal">J</a:mi> <a:mo>/</a:mo> <a:mi>ψ</a:mi> </a:math> production in <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"> <d:mi>γ</d:mi> <d:mo>+</d:mo> <d:mi>p</d:mi> </d:math> and <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"> <f:mi>γ</f:mi> <f:mo>+</f:mo> <f:mi>Pb</f:mi> </f:math> collisions using a color glass condensate (CGC) based calculation framework. As past calculations have shown that CGC-based models typically overpredict the <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"> <h:mi mathvariant="normal">J</h:mi> <h:mo>/</h:mo> <h:mi>ψ</h:mi> </h:math> production in <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:mi>γ</k:mi> <k:mo>+</k:mo> <k:mi>Pb</k:mi> </k:math> collisions at high center of mass energy, we address the question of whether it is possible to describe coherent and incoherent diffractive <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:mi mathvariant="normal">J</m:mi> <m:mo>/</m:mo> <m:mi>ψ</m:mi> </m:math> data from <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"> <p:mi>γ</p:mi> <p:mo>+</p:mo> <p:mi>p</p:mi> </p:math> collisions at Hadron–Electron Ring Accelerator (HERA) and the LHC, and from <r:math xmlns:r="http://www.w3.org/1998/Math/MathML" display="inline"> <r:mi>γ</r:mi> <r:mo>+</r:mo> <r:mi>Pb</r:mi> </r:math> collisions at the LHC simultaneously. Our results indicate that a simultaneous description of <t:math xmlns:t="http://www.w3.org/1998/Math/MathML" display="inline"> <t:mi>γ</t:mi> <t:mo>+</t:mo> <t:mi>p</t:mi> </t:math> and <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline"> <v:mi>γ</v:mi> <v:mo>+</v:mo> <v:mi>Pb</v:mi> </v:math> data is challenging, with results improving when an overall <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"> <x:mi>K</x:mi> </x:math> -factor—scaling <z:math xmlns:z="http://www.w3.org/1998/Math/MathML" display="inline"> <z:mi>γ</z:mi> <z:mo>+</z:mo> <z:mi>p</z:mi> </z:math> and <bb:math xmlns:bb="http://www.w3.org/1998/Math/MathML" display="inline"> <bb:mi>γ</bb:mi> <bb:mo>+</bb:mo> <bb:mi>Pb</bb:mi> </bb:math> cross sections to absorb model uncertainties—is introduced.